FIELD OF THE INVENTION
[0001] The present invention relates to an image-recording material, in particular, to a
photothermographic or thermographic material excellent in silver tone.
BACKGROUND OF THE INVENTION
[0002] A photothermographic or thermographic material has been proposed for long and described,
for example, in U.S. Patents 3,152,904 and 3,457,075, D. Klosterboer,
Thermally Processed Silver System, "Imaging Processes and Materials", compiled by Sturge, V. Walworth, A. Shepp, 8th
Ed., Neblette, p. 279 (1989). A photothermographic material generally has a photosensitive
layer comprising a catalytically active amount of photocatalyst (e.g., silver halide),
a reducing agent, a reducible silver salt (e.g., organic silver salt), and a toning
agent which controls the tone of silver according to necessity dispersed in a binder
matrix. A photothermographic material forms a silver image of black color by heating
at high temperature (e.g., 80°C or more) after image exposure to cause an oxidation
reduction reaction between silver halide or a reducible silver salt (functioning as
an oxidizing agent) with a reducing agent. The oxidation reduction reaction is accelerated
by the catalytic action of the latent image of the silver halide generated by exposure.
Therefore, the silver image of black color is formed in the exposure region.
[0003] A photothermographic material is generally stored as a bulk product after coating
until processed and shipped. The storage stability of a coated bulk product during
that time is not good and the improvement of the storage stability is desired. Further,
it is desired that the tint of a silver image is not varied by the photothermographic
temperature.
SUMMARY OF THE INVENTION
[0004] An object of the present invention is to improve the storage stability of a coated
bulk product and silver tone in a (photo)thermographic material, in particular, a
photothermographic material.
[0005] The above object of the present invention has been achieved by the following means.
(1) An image-recording material which has at least on one surface side of a support
a thermosensitive recording element containing a scaly organic acid silver salt, a
reducing agent for a silver ion, and a binder, or a photosensitive recording element
containing a scaly organic acid silver salt, a reducing agent for a silver ion, photosensitive
silver halide, and a binder, wherein the NH4+ content of all the layers on the surface side of the support which has the thermosensitive
or photosensitive recording element is from 0.06 to 3.4 mmol as the coating amount
per m2 of the support.
(2) The material as described in the above item (1), wherein the NH4+ content is from 0.55 to 2.8 mmol as the coating amount per m2 of the support.
(3) The material as described in the above item (1) or (2), wherein the alkali metal
ion content of all the layers on the surface side of the support which has the thermosensitive
or photosensitive recording element is from 0.05 to 3.6 mmol as the coating amount
per m2 of the support.
(4) The material as described in the above item (3), wherein the alkali metal ion
content is from 0.59 to 3.0 mmol as the coating amount per m2 of the support.
(5) The material as described in any of the above item (3) or (4), wherein the alkali
metal ion is Li+, Na+, or K+.
(6) The material as described in any of the above items (3) to (5), wherein the ratio
of the contents of the alkali metal ion and NH4+, i.e., (NH4+)/(alkali metal ion), is from 0.01 to 30 in molar ratio.
(7) The material as described in any of the above items (3) to (5), wherein the ratio
of (NH4+)/(alkali metal ion) is from 0.1 to 20.
(8) The material as described in any of the above items (3) to (5), wherein the ratio
of (NH4+)/(alkali metal ion) is from 0.5 to 5.
(9) The material as described in any of the above items (1) to (8), wherein the layer
containing a scaly organic acid silver salt further contains a phthalic acid compound
represented by formula (I):
wherein R1, R2, R3 and R4 each represents a hydrogen atom or a monovalent substituent; L1 and L2 each represents a linking group; n1 and n2 each represents 0 or 1; M represents a hydrogen atom or a counter ion; and k represents
a valency of M, and when M represents a hydrogen atom, k represents 1, provided that
when M represents a hydrogen atom and n1 and n2 each represents 0, not all R1, R2, R3 and R4 represent a hydrogen atom.
(10) The material as described in the above item (9), wherein M in formula (I) represents
an ammonium ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion,
a zinc ion, an ionic polymer, an organic compound having reverse charge, or a metal
complex ion.
(11) The material as described in any of the above items (1) to (10), wherein the
silver behenate content of the organic acid silver salt is 92 mol% or more.
(12) The material as described in any of the above items (1) to (11), wherein the
layer containing the scaly organic acid silver salt is formed by coating a coating
solution in which 30% by weight or more of the solvent is occupied by water, and then
drying, and the main binder of this layer is a polymer having an equilibrium moisture
content at 25°C 60% RH of 2% by weight or less.
(13) The material as described in any of the above items (1) to (12), wherein the
material contains a photosensitive recording element.
(14) The material as described in the above item (13), wherein the material has two
or more constitutional layers including the photosensitive recording element on the
same surface side of the support on which the photosensitive recording element is
provided and these two or more constitutional layers are simultaneously coated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Fig. 1 is a schematic cross-sectional view showing one example of a heat developing
unit in a plate heater system for use in the present invention.
[0007] Fig. 2 is a schematic cross-sectional view showing another example of a heat developing
unit in a plate heater system for use in the present invention.
Key to the Symbols
[0008]
- 18:
- Heat developing unit
- 120:
- Plate heater
- 122:
- Pressing roller
- 130:
- Driving roller
DETAILED DESCRIPTION OF THE INVENTION
[0009] The present invention will be described in detail below.
[0010] The photothermographic material according to the present invention contains at least
on one surface side of the support a scaly organic acid silver salt, a reducing agent
for a silver ion, and a binder, and contains NH
4+ in total of all the layers on the surface side of the support which contains the
above components of from 0.06 to 3.4 mmol as the coating amount per m
2 of the support, or contains an alkali metal ion in total of all the layers on the
surface side of the support which contains the above components of from 0.05 to 3.6
mmol as the coating amount per m
2 of the support. By using such a scaly organic acid silver salt and a prescribed amount
of NH
4+ or an alkali metal ion, less silver tone difference is generated due to heat development
conditions, as a result good silver tone can be obtained by any heat development condition,
thus a photothermographic material showing less photographic characteristic fluctuation
due to the storage of a coated bulk product can be obtained. Contrary to this, when
an acicular organic acid silver salt is used, not only the storage stability lowers
but also the silver tone is deteriorated. On the other hand, if the amounts of NH
4+ or an alkali metal ion are less than the above range, neither the silver tone is
improved nor the storage stability is sufficient. While when the amounts of NH
4+ or an alkali metal ion are larger than the above range, the storage stability decreases.
[0011] Further, it is also preferred to contain both NH
4+ and an alkali metal ion for obtaining preferred silver tone and storage stability,
and the ratio of (NH
4+)/(alkali metal ion) is from 0.1 to 20.
[0012] Li
+, Na
+, or K
+ is preferred as the alkali metal ion for use in the present invention.
[0013] In the present invention, NH
4+ and an alkali metal ion may be added as an alkali solution such as NH
4OH, alkali hydroxide metal ion (e.g., LiOH, NaOH, KOH) or they may be added in the
form of a salt formed with an acid, alternatively they may be added as a salt formed
with other photographically useful substances.
[0014] These compounds are added to the coating solution of the layer coated on the same
surface side of the support as the layer containing an organic acid silver. When they
are added as an alkali solution, a solution of from 0.1 to 40% by weight is preferably
used, and when added in the form of a salt, any of a solution, a powder and a solid
fine particle dispersion may be used.
[0015] The addition amount of NH
4+ is from 0.06 to 3.4 mmol/ m
2, preferably from 0.55 to 2.8 mmol/m
2, and the addition amount of an alkali metal ion is from 0.05 to 3.6 mmol/m
2, preferably from 0.59 to 3.0 mmol/m
2. They may be used NH
4+ alone or an alkali metal ion alone but they are preferably used in combination, and
the addition amount in this case is from 0.11 to 7.0 mmol/m
2, preferably from 1.14 to 6.4 mmol/ m
2. The ratio of (NH
4+)/(alkali metal ion) in this case is from 0.01 to 30, preferably from 0.1 to 20, and
more preferably from 0.5 to 5.
[0016] NH
4+ and an alkali metal ion may be added to any of an organic acid silver-containing
layer, a photosensitive layer, an interlayer, or a protective layer, and they may
be added to two or more layers.
[0017] It is also preferred that they are added to a photosensitive layer by being added
to the main binder of a photosensitive layer, which will be described later, or added
as a dicarboxylic acid salt used as a tone adjustor, which will be also described
later.
[0018] The layer containing an organic acid silver salt (an image-recording layer) of the
photothermographic material according to the present invention can be formed by water
system coating with an environment-friendly coating solution in which 30% by weight
or more of the solvent is occupied by water, and it is preferred to use a polymer
having an equilibrium moisture content at 25°C 60% RH of 2% by weight or less, which
is preferred for obtaining good photographic performances, as the main binder of this
layer. The photothermographic material according to the present invention preferably
has a photosensitive layer containing photosensitive silver halide provided on the
same surface side of the support as the layer containing an organic acid silver salt.
It is particularly preferred for the organic acid silver salt-containing layer to
contain photosensitive silver halide. It is also preferred from the viewpoint of the
production to use a hydrophilic binder as the main binder of the constituting layers
such as interlayer and the protective layer which are provided on the same surface
side as the organic acid silver salt-containing layer (preferably the photosensitive
layer) and the organic acid silver salt-containing layer is coated simultaneously
with these layers.
[0019] Photo-insensitive organic acid silver salts for use in the present invention are
scaly and they are preferably contained in a photosensitive layer or a photo-insensitive
layer. Organic acids for forming silver salts are preferably long chain fatty acids
preferably having from 10 to 30 carbon atoms, and more preferably from 15 to 25 carbon
atoms. Organic silver salt complexes may also be used. The ligands of complexes preferably
have the total stability constant against silver ions of from 4.0 to 10.0. Organic
silver salts are described in
Research Disclosure, No. 17029 and
ibid., No. 29963.
[0020] Examples of organic silver salts include silver salts of fatty acids (e.g., gallic
acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid), silver
salts of carboxyalkylthioureas (e.g., 1-(3-carboxypropyl)thiourea, 1-(3-carboxypropyl)-3,3-dimethylthiourea),
silver complexes of the polymerization reaction products of aldehydes (e.g., formaldehyde,
acetaldehyde, butyraldehyde) with hydroxysubstituted aromatic carboxylic acids, silver
salts of aromatic carboxylic acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic
acid, 5,5-thiodisalicylic acid), silver salts or silver complexes of thioenes (e.g.,
3-(2-carboxyethyl)-4-hydroxymethyl-4-thiazoline-2-thioene, 3-carboxymethyl-4-thiazoline-2-thioene),
silver salts or silver complexes of nitrogen acids (e.g., imidazole, pyrazole, urazol,
1,2,4-thiazole, 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole, benzotriazole),
silver salts of saccharin, silver salt of 5-chlorosalicylaldoxime, and silver salts
of mercaptides.
[0021] In the present invention, scaly organic acid silver salts are selected from among
these compounds. It is preferred to use scaly organic acid silver salts alone as organic
silver salts, but the above organic silver salts may also be used in combination with
organic acid silver salts if the amount is within the range of 30 wt% or less of the
entire amount. Fatty acid silver is preferred as an organic acid silver salt, in particular,
organic acid silver salts containing 92 mol% or more of silver behenate are preferred,
and silver behenate is most preferred. Organic acid silver salts are preferably used
in an amount of from 0.05 to 3 g/m
2, more preferably from 0.3 to 2 g/m
2, as a silver amount.
[0022] As scaly organic acid silver salts are used in the present invention, "scaly" is
judged as follows: An organic acid silver salt is observed with an electron microscope,
the shape of the organic acid silver salt particle is approximated to a rectangular
parallelopiped, and when the sides of the rectangular parallelopiped are taken as
a, b and c from the shortest (c may be equal to b), x is calculated from the shorter
numeric values a and b as follows:
x is obtained about 200 particles by the above equation, and when the average
value is taken as x (average), those satisfy the relationship x (average) > 1.5 are
regarded as scaly particles, preferably 30 > x (average) > 1.5, more preferably 20
> x (average) > 2.0. In this connection, acicular is 1 < x (average) < 1.5.
[0023] In a scaly particle, a can be regarded as a thickness of a tubular particle having
a plane making b and c the sides as a main plane. The average of a is preferably from
0.01 to 0.23 µm, and more preferably from 0.1 to 0.20 µm. The average of c/b is preferably
from 1 to 6, more preferably from 1.05 to 4, still more preferably from 1.1 to 3,
and particularly preferably from 1.1 to 2.
[0024] When an aqueous solution containing a water-soluble silver salt and an aqueous tertiary
alcohol solution containing an organic acid alkali metal salt are reacted in a reaction
vessel (including the step of adding the aqueous tertiary alcohol solution containing
an organic acid alkali metal salt to the solution in the reaction vessel), scaly organic
acid silver salt is preferably formed in a manner so as to make the temperature difference
between the solution in the reaction vessel (preferably the aqueous solution containing
a water-soluble silver salt added to the reaction vessel in advance, or in the case
when the aqueous solution containing a water-soluble silver salt is not previously
added but added simultaneously with the aqueous tertiary alcohol solution containing
an organic acid alkali metal salt from the first, the solution in the reaction vessel
is water or a mixed solvent of water and a tertiary alcohol as later described, further
also in the case when the aqueous solution containing a water-soluble silver salt
is added to the reaction vessel in advance, water or a mixed solvent of water and
a tertiary alcohol may previously be added to the vessel) and the aqueous tertiary
alcohol solution containing an organic acid alkali metal salt to be added to the reaction
vessel from 20°C to 85°C. By maintaining the temperature difference during the addition
of the aqueous tertiary alcohol solution containing an organic acid alkali metal salt,
the crystal form of the organic acid silver salt is advantageously controlled.
[0025] As this water-soluble silver salt, silver nitrate is preferred, and as the concentration
of the water-soluble silver salt in the aqueous solution is preferably from 0.03 to
6.5 mol/liter, more preferably from 0.1 to 5 mol/liter, and the pH of the aqueous
solution is preferably from 2 to 6, more preferably from 3.5 to 6.
[0026] A tertiary alcohol having from 4 to 6 carbon atoms may be contained in the aqueous
solution containing a water-soluble silver salt, and in such a case the content of
the tertiary alcohol is 70% by volume or less, preferably 50% by volume or less, based
on the total volume of the aqueous solution containing a water-soluble silver salt.
The temperature of the solution is preferably from 0°C to 50°C, more preferably from
5°C to 30°C. When the aqueous solution containing a water-soluble silver salt is added
simultaneously with the aqueous tertiary alcohol solution containing an organic acid
alkali metal salt, the temperature is preferably from 5°C to 15°C as is described
later.
[0027] The alkali metal of the organic acid alkali metal salt is specifically Na or K. Organic
acid alkali metal salt is produced by adding NaOH or KOH to an organic acid. It is
preferred to make the weight of the alkali equivalent or less of the weight of the
organic acid at that time to leave an unreacted organic acid. The residual organic
acid amount at this time is from 3 to 50 mol%, preferably from 3 to 30 mol%, per mol
of the entire organic acid. Further, alkali of the amount larger than the prescribed
amount is added and the excess amount of alkali may be neutralized afterward by adding
an acid such as a nitric acid or a sulfuric acid.
[0028] Further, pH can be adjusted by the required characteristics of the organic acid silver
salt. For pH adjustment, arbitrary acids and alkalis can be used.
[0029] There may be added to the aqueous solution containing a water-soluble silver salt,
the aqueous tertiary alcohol solution containing an organic acid alkali metal salt,
or the solution in the reaction vessel, for example, a compound represented by formula
(1) as disclosed in JP-A-62-65035 (the term "JP-A" as used herein means an "unexamined
published Japanese patent application"), an N heterocyclic compound having a water-soluble
group as disclosed in JP-A-62-150240, an inorganic peroxide as disclosed in JP-A-50-101019,
a sulfur compound as disclosed in JP-A-51-78319, a disulfide compound as disclosed
in JP-A-57-643, or a hydrogen peroxide.
[0030] The aqueous tertiary alcohol solution containing an organic acid alkali metal salt
according to the present invention is preferably a mixed solvent of a tertiary alcohol
having from 4 to 6 carbon atoms and water for obtaining the homogeneity of the solution.
If the carbon atom number exceeds this range, the compatibility with water is deteriorated,
which is not advantageous. Of tertiary alcohols having from 4 to 6 carbon atoms, tert-butanol
which is most compatible with water is most preferred. Since alcohols other than tertiary
alcohols have reducibility, harmful influences are disadvantageously caused in the
organic acid metal salt formation as described above. The content of the tertiary
alcohols contained in the aqueous tertiary alcohol solution containing an organic
acid alkali metal salt is from 3 to 70%, preferably from 5 to 50%, by volume of the
solvent based on the volume of the water content in the aqueous tertiary alcohol solution.
[0031] The concentration of the organic acid alkali metal salt in the aqueous tertiary alcohol
solution containing an organic acid alkali metal salt for use in the present invention
is from 7 to 50 wt%, preferably from 7 to 45 wt%, and more preferably from 10 to 40
wt%, by weight ratio.
[0032] The temperature of the aqueous tertiary alcohol solution containing an organic acid
alkali metal salt added to the reaction vessel is preferably from 50 to 90°C, more
preferably from 60 to 85°C, and most preferably from 65 to 85°C, for the purpose of
maintaining the necessary temperature to prevent phenomena such as crystallization
and solidification of the organic acid alkali metal salt. The temperature is preferably
controlled at a certain temperature selected from the above range throughout the reaction.
[0033] The organic acid silver salt according to the present invention is produced by i)
the method in which the total amount of the aqueous solution containing a water-soluble
silver salt is added to the reaction vessel in advance and then the aqueous tertiary
alcohol solution containing an organic acid alkali metal salt is added thereto (a
single addition method), or ii) the method in which the aqueous solution containing
a water-soluble silver salt and the aqueous tertiary alcohol solution containing an
organic acid alkali metal salt are added simultaneously at least for some period of
time (a simultaneous addition method). The latter simultaneous addition method is
preferably used in the present invention for controlling the average particle size
of the organic acid silver salt and making the particle size distribution narrow.
In such a case, preferably 30 vol% or more, more preferably from 50 to 75 vol%, of
the total addition amount is added simultaneously. When either one is added beforehand,
the aqueous solution containing a water-soluble silver salt is preferably added first.
[0034] In any case, the temperature of the solution in the reaction vessel (the aqueous
solution containing a water-soluble silver salt added in advance, or when the aqueous
solution containing a water-soluble silver salt is not added precedently, the solvent
previously added in the reaction vessel) is preferably from 5°C to 75°C, more preferably
from 5°C to 60°C, and most preferably from 10°C to 50°C. The temperature is preferably
controlled at a certain temperature selected from the above range throughout the reaction,
but it is also preferred to control the temperature in some patterns within the above
range.
[0035] In the present invention, the temperature difference between the aqueous tertiary
alcohol solution containing an organic acid alkali metal salt and the solution in
the reaction vessel is preferably from 20°C to 85°C, more preferably from 30°C to
80°C. In this case, it is preferred that the temperature of the aqueous tertiary alcohol
solution containing an organic acid alkali metal salt is higher than that of the solution
in the reaction vessel.
[0036] Thus, the rate of crystallite-like precipitation of the aqueous tertiary alcohol
solution containing an organic acid alkali metal salt of high temperature as a result
of sudden quenching in the reaction vessel and the rate of coming into an organic
acid silver salt by the reaction with the water-soluble silver salt are preferably
controlled. As a result, the crystal shape and the crystal size of the organic acid
silver salt and the crystal size distribution can be preferably controlled. At the
same time, the characteristics of the photothermographic material, in particular,
the photothermographic photosensitive material, can be further improved.
[0037] A solvent may be put in a reaction vessel in advance, e.g., water is preferably used
as a solvent previously added and a mixed solvent of a tertiary alcohol with water
is also preferably used.
[0038] An dispersing aid which is soluble in an aqueous medium can be added to the aqueous
tertiary alcohol solution containing an organic acid alkali metal and the aqueous
solution containing a water-soluble silver salt according to the present invention,
or the reaction solution. Any compound can be used as the dispersing aid so long as
it can disperse the organic acid silver salt formed. Specific examples correspond
to the dispersing aids of organic acid silver salts described later.
[0039] In the preparing method of the organic acid silver salt according to the present
invention, it is preferred to perform desalting/dehydrating process after silver salt
formation. Methods of desalting/dehydrating are not particularly restricted and well-known
conventional means can be utilized. For example, well-known filtration methods such
as centrifugal filtration, suction filtration, ultrafiltration, and washing of floc
formed by agglomeration can be preferably used. The removal of a supernatant by centrifugal
separation precipitation is also preferably used. Desalting/dehydrating may be performed
only one time or may be repeated a plurality of times. Addition and removal of water
may be performed continuously or separately. Desalting/dehydrating is performed until
the conductivity of the dehydrated water finally reaches preferably 300 µS/cm or less,
more preferably 100 µS/cm or less, and most preferably 60 µS/cm or less. The lower
limit of the conductivity in this case is not particularly limited but is generally
about 5 µS/cm.
[0040] Further, for improving the coating surface condition of a photothermographic material,
in particular, a photothermographic photosensitive material, it is preferred to prepare
a water dispersion of an organic acid silver salt, convert the obtained dispersion
to high pressure and high flow rate, and redisperse by pressure drop to obtain a fine
water dispersion. The dispersion medium at this time is preferably water alone, but
an organic solvent may be contained if the amount is 20 wt% or less.
[0041] An organic acid silver salt can be mechanically finely dispersed in the presence
of a dispersing aid using well-known dispersing means (e.g., a high speed mixer, a
homogenizer, a high speed impacting mill, a banbury mixer, a homomixer, a kneader,
a ball mill, a vibrating ball mill, a planetary ball mill, an attritor, a sand mill,
a beads mill, a colloid mill, a jet mill, a roller mill, a trommel and a high speed
stone mill).
[0042] For obtaining fine particles of an organic acid silver salt having a small particle
size and without agglomeration which can be used in the present invention, a method
of obtaining a solid fine particle dispersion with a dispersant is used in the present
invention. After the water dispersion of an organic acid silver salt obtained by the
method of the present invention is converted to high pressure/high flow rate, a method
of redispersing the dispersion by pressure drop is preferably used.
[0043] Further, if a photosensitive silver salt is present with the organic acid silver
salt during dispersion, fog increases and sensitivity extremely lowers. Thus, it is
more preferred not to substantially contain a photosensitive silver salt in the water
dispersion solution. The content of a photosensitive silver salt in the water dispersion
solution to be dispersed is 0.1 mol% or less per mol of the organic acid silver salt
in the solution, where the addition of a photosensitive silver salt is not performed
positively.
[0044] Solid dispersing apparatuses and techniques for performing the foregoing dispersion
are described in detail, for example, in Toshio Kajiuchi, Hiroshi Usui,
Rheology of Dispersion System and Techniques of Dispersion, pp. 357 to 403, Shinoyama Publishing Co., Ltd. (1991),
Advancement of Chemical Engineering, the 24th Series, pp. 184 and 185, compiled by the Tokai Branch of the Chemical Engineering Society,
published by Maki Shoten (1990), JP-A-59-49832, U.S. Patent 4,533,254, JP-A-8-137044,
JP-A-8-238848, JP-A-2-261525, JP-A-1-94933, etc. The redispersing method according
to the present invention is a method in which a water dispersion solution containing
at least an organic acid silver salt is fed to piping by high pressure using a high
pressure pump and the like, passed through a fine slit in the piping, and then the
pressure applied to the dispersion solution is suddenly reduced to thereby effect
fine dispersion.
[0045] The reason why the dispersion to fine particles can be brought about by using a high
pressure homogenizer is thought to be due to dispersion forces such as (a) "shear
force" generated when a dispersoid passes through a narrow gap at high pressure and
a high flow rate, and (b) "cavitation force" generated when the dispersoid is released
from high pressure to atmospheric pressure. As a dispersing apparatus of this type,
a Gaulin homogenizer has so far been used, wherein a dispersoid fed at high pressure
is converted to high flow rate in a narrow gap on cylindrical plane, the dispersoid
is impinged against the surrounding walls by that force, and emulsification and dispersion
are effected by that impact force. The applied pressure is in general within the range
of from 100 to 600 kg/cm
2 and a flow rate is from several meters to 30 meters/second, and some means have been
elaborated to heighten a dispersion efficiency, such as to provide sawtooth blades
at high flow rate zone to increase the number of times of impinging. On the other
hand, apparatuses which make it possible to realize dispersion at higher pressure
and a higher flow rate have been developed. By way of representative examples, a micro-fluidizer
(manufactured by Micro Fluidex International Corp.) and a nanomizer (manufactured
by Tokushu Kika Kogyo Co., Ltd.) are exemplified.
[0046] In the present invention, it is possible to achieve the dispersion of the organic
acid silver salt of the desired particle size by adjusting flow rate, differential
pressure at the time of pressure drop, and the number of times of processing. From
the viewpoint of the photographic characteristics and the particle size, the flow
rate is preferably from 200 to 600 m/second, more preferably from 300 to 600 m/ second,
and differential pressure at pressure drop is preferably from 900 to 3,000 kg/cm
2, more preferably from 1,500 to 3,000 kg/cm
2. The number of times of dispersion processing can be selected according to necessity
and, in general, from 1 to 10 times, but in view of productivity, preferably from
1 to 3 or so. It is not preferred in the light of dispersion properties and photographic
characteristics to maintain the temperature of a water dispersion solution high under
high pressure, and when the temperature exceeds 90°C, the particle size is liable
to increase and fog is also liable to increase. Accordingly, it is preferred in the
present invention to include a cooling process in steps prior to conversion to high
pressure/high flow rate, after pressure drop, or in both steps, to thereby maintain
the temperature of the water dispersion preferably from 5 to 90°C, more preferably
from 5 to 80°C, and particularly preferably from 5 to 65°C. In particular, it is effective
to provide such a cooling process during high pressure dispersion of from 1,500 to
3,000 kg/cm
2. A cooler can be arbitrarily selected from, e.g., a double pipe and a triple pipe
using a static mixer, a multitubuler heat exchanger, and a coiled heat exchanger,
according to the required heat exchange amount. Further, for increasing heat exchange
efficiency, it is necessary to select appropriate diameter, thickness and material
of the pipe with taking the pressure used into consideration. As a cooling medium
in a cooler, well water of 20°C, chilled water of from 5 to 10°C treated with a refrigerator,
or, if necessary, a cooling medium such as ethylene glycol/water of -30°C can be used
according to heat exchange amount.
[0047] When a solid fine particle atomization of an organic acid silver salt is carried
out using a dispersant, the following dispersants can be arbitrarily selected, e.g.,
synthetic anion polymers such as polyacrylic acid, acrylic acid copolymers, maleic
acid copolymers, maleic acid monoester copolymers, and acryloylmethylpropane sulfonic
acid copolymers, semi-synthetic anion polymers such as carboxymethyl starch and carboxymethyl
cellulose, anionic polymers such as alginic acid and pectic acid, anionic surfactants
disclosed in JP-A-52-92716 and WO 88/04794, compounds disclosed in JP-A-7-350753,
well-known anionic, nonionic and cationic surfactants, other well-known polymers such
as polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, hydroxypropyl
cellulose, and hydroxypropylmethyl cellulose, and natural high molecular compounds
such as gelatin.
[0048] A dispersing aid is in general mixed with the powder of an organic acid silver salt
or an organic acid silver salt in a wet cake-like state before dispersion and fed
to a dispersing apparatus as a slurry. Alternatively, a dispersing aid may be previously
mixed with an organic acid silver salt and Subjected to heat treatment or treatment
with a solvent and then made into an organic acid silver salt powder or wet cake.
pH adjustment may be performed before, after or during dispersion with an appropriate
pH adjustor.
[0049] In addition to mechanical dispersion, organic acid silver salt may be coarsely dispersed
in a solvent by pH controlling, and then atomized by changing pH in the presence of
a dispersing aid. At this time, an organic solvent may be used for coarse dispersion
and the organic solvent is in general removed after completion of the atomization.
[0050] The prepared dispersion can be preserved with stirring or in a highly viscous state
with hydrophilic colloid (for example, in a jelly-like state using gelatin) for the
purpose of preventing the precipitation of fine particles during preservation. Further,
it is preferred to add preservatives for inhibiting the proliferation of various bacteria.
[0051] The organic acid silver salt prepared according to the producing method of the organic
acid silver salt of the present invention is preferably dispersed in a water solvent,
mixed with an aqueous photosensitive silver salt solution, and supplied as a coating
solution for a photosensitive image-forming medium.
[0052] Examples of reducing agents preferably used in the present invention include phenidone,
hydroquinones, catechol and hindered phenol. With respect to reducing agents, U.S.
Patents 3,770,448, 3,773,512, 3,593,863, 4,460,681, and
Research Disclosure, No. 17029 and
ibid., No. 29963 can be referred to.
[0053] Specific examples of reducing agents include an aminohydroxycycloalkenone compound
(e.g., 2-hydroxy-piperidino-2-cyclohexenone), an N-hydroxyurea derivative (e.g., N-p-methylphenyl-N-hydroxyurea),
hydrazones of aldehyde or ketone (e.g., anthracenealdehydephenylhydrazone), phosphor
amidophenols, phosphor amidoanilines, polyhydroxybenzenes (e.g., hydroquinone, t-butylhydroquinone,
isopropylhydroquinone, 2,5-dihydroxyphenylmethylsulfone), sulfohydroxamic acids (e.g.,
benzenesulfohydroxamic acid), sulfonamidoanilines (e.g., 4-(N-methanesulfonamido)aniline),
2-tetrazolylthiohydroquinones (e.g., 2-methyl-5-(1-phenyl-5-tetrazolylthio)hydroquinone),
tetrahydroquinoxalines (e.g., 1,2,3,4-tetrahydroquinoxaline), amidoxines, combinations
of azines (e.g., aliphatic carboxylic acid arylhydrazides) with ascorbic acid, combinations
of polyhydroxybenzene hydroxylamine, reductone, hydrazine, hydroxamic acids, combinations
of azines with sulfonamidophenols, an α-cyanophenylacetic acid derivative, combinations
of bis-β-naphthol with a 1,3-dihydroxybenzene derivative, 5-pyrazolones, sulfonamidophenols,
2-phenylindane-1,3-dione, chroman, 1,4-dihydropyridines (e.g., 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine),
bisphenols (e.g., bis (2-hydroxy-3-t-butyl-5-methylphenyl)methane, bis(6-hydroxy-m-tri)mesitol,
2,4-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis (2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane,
4,4-ethylidene-bis(2-t-butyl-6-methyl)phenol), UV-sensitive ascorbic acid derivatives,
and 3-pyrazolidones.
[0054] Esters of amino reductones which function as a reducing agent precursor (e.g., piperidinohexose
reductone monoacetate) may be used as a reducing agent.
[0055] A particularly preferred reducing agent is hindered phenol.
[0056] The addition amount of a reducing agent is preferably from 0.01 to 5.0 g/m
2, more preferably from 0.1 to 3.0 g/m
2.
[0057] The photothermographic material according to the present invention comprises a support
having provided thereon a layer containing a scaly organic acid silver salt (i.e.,
an image-recording layer); and contains a reducing agent for a silver ion and a binder,
and preferably a phthalic acid compound represented by formula (I) on the same surface
side of the support as the layer containing an organic acid silver salt. The photothermographic
material according to the present invention is preferably a photothermographic photosensitive
material which contains a photosensitive silver halide on the same surface side of
the support as the layer containing an organic acid silver salt. Particularly preferably
the organic acid silver salt containing-layer contains a photosensitive silver halide.
Still more preferably a reducing agent for a silver ion is also contained in the same
layer. In this photothermographic photosensitive material, by using a scaly organic
acid silver salt as an organic acid silver salt and a phthalic acid compound represented
by formula (I), less silver tone difference is generated due to heat development conditions,
as a result good silver tone can be obtained by any heat development condition, thus
a photothermographic material showing less photographic characteristic fluctuation
due to the storage can be obtained. Contrary to this, when an acicular organic acid
silver salt is used, not only the storage stability lowers but also the silver tone
is deteriorated. On the other hand, when a compound such as a phthalic acid which
is different from the phthalic acid compound represented by formula (I) alone is used,
the silver tone is in particular deteriorated.
[0058] For improving the storage stability, organic acid silver salts containing 92 mol%
or more of a silver behenate are preferably used. Further, the organic acid silver
salt-containing layer can be formed by water system coating with an environment-friendly
coating solution in which 30% by weight or more of the solvent is occupied by water,
and it is preferred to use a polymer having an equilibrium moisture content at 25°C
60% RH of 2% by weight or less, which is preferred for obtaining good photographic
performances, as the main binder of this layer. It is also preferred from the viewpoint
of the production to use a hydrophilic binder as the main binder of the interlayer
and the protective layer which are provided on the same surface side as the organic
acid silver salt-containing layer and the organic acid silver salt-containing layer
is coated simultaneously with these constituting layers.
[0059] A phthalic acid compound represented by formula (I) will be described in detail below.
wherein R
1, R
2, R
3 and R
4 each represents a hydrogen atom or a monovalent substituent; n
1 and n
2 each represents 0 or 1; M represents a hydrogen atom or a counter ion, provided that
when M represents a hydrogen atom and n
1 and n
2 each represents 0, not all R
1, R
2, R
3 and R
4 represent a hydrogen atom. Examples of monovalent substituents represented by R
1, R
2, R
3 and R
4 include an alkyl group (preferably an alkyl group having from 1 to 20, more preferably
from 1 to 12, and particularly preferably from 1 to 8, carbon atoms, e.g., methyl,
ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl,
cyclopropyl, cyclopentyl, cyclohexyl), an alkenyl group (preferably an alkenyl group
having from 2 to 20, more preferably from 2 to 12, and particularly preferably from
2 to 8, carbon atoms, e.g., vinyl, allyl, 2-butenyl, 3-pentenyl), an alkynyl group
(preferably an alkynyl group having from 2 to 20, more preferably from 2 to 12, and
particularly preferably from 2 to 8, carbon atoms, e.g., propargyl, 3-pentynyl), an
aryl group (preferably an aryl group having from 6 to 30, more preferably from 6 to
20, and particularly preferably from 6 to 12, carbon atoms, e.g., phenyl, p-methylphenyl,
naphthyl), an amino group (preferably an amino group having from 0 to 20, more preferably
from 0 to 10, and particularly preferably from 0 to 6, carbon atoms, e.g., amino,
methylamino, dimethylamino, diethylamino, dibenzylamino), an alkoxyl group (preferably
an alkoxyl group having from 1 to 20, more preferably from 1 to 12, and particularly
preferably from 1 to 8, carbon atoms, e.g., methoxy, ethoxy, butoxy, benzyloxy), an
aryloxy group (preferably an aryloxy group having from 6 to 20, more preferably from
6 to 16, and particularly preferably from 6 to 12, carbon atoms, e.g., phenyloxy,
2-naphthyloxy), an acyl group (preferably an acyl group having from 1 to 20, more
preferably from 1 to 16, and particularly preferably from 1 to 12, carbon atoms, e.g.,
acetyl, benzoyl, formyl, pivaloyl), an alkoxycarbonyl group (preferably an alkoxycarbonyl
group having from 2 to 20, more preferably from 2 to 16, and particularly preferably
from 2 to 12, carbon atoms, e.g., methoxycarbonyl, ethoxycarbonyl, tetradecyloxycarbonyl),
an aryloxycarbonyl group (preferably an aryloxycarbonyl group having from 7 to 20,
more preferably from 7 to 16, and particularly preferably from 7 to 10, carbon atoms,
e.g., phenyloxycarbonyl), an acyloxy group (preferably an acyloxy group having from
2 to 20, more preferably from 2 to 16, and particularly preferably from 2 to 10, carbon
atoms, e.g., acetoxy, benzoyloxy), an acylamino group (preferably an acylamino group
having from 2 to 20, more preferably from 2 to 16, and particularly preferably from
2 to 10, carbon atoms, e.g., acetylamino, propionylamino, benzoylamino), an alkoxycarbonylamino
group (preferably an alkoxycarbonylamino group having from 2 to 20, more preferably
from 2 to 16, and particularly preferably from 2 to 12, carbon atoms, e.g., methoxycarbonylamino),
an aryloxycarbonylamino group (preferably an aryloxycarbonylamino group having from
7 to 20, more preferably from 7 to 16, and particularly preferably from 7 to 12, carbon
atoms, e.g., phenyloxycarbonylamino), a sulfonylamino group (preferably a sulfonylamino
group having from 1 to 20, more preferably from 1 to 16, and particularly preferably
from 1 to 12, carbon atoms, e.g., methanesulfonylamino, octanesulfonylamino, benzenesulfonylamino),
a sulfamoyl group (preferably a sulfamoyl group having from 0 to 20, more preferably
from 0 to 16, and particularly preferably from 0 to 12, carbon atoms, e.g., sulfamoyl,
methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl), a carbamoyl group (preferably
a carbamoyl group having from 1 to 20, more preferably from 1 to 16, and particularly
preferably from 1 to 12, carbon atoms, e.g., carbamoyl, methylcarbamoyl, diethylcarbamoyl,
phenylcarbamoyl), an alkylthio group (preferably an alkylthio group having from 1
to 20, more preferably from 1 to 16, and particularly preferably from 1 to 12, carbon
atoms, e.g., methylthio, ethylthio), an arylthio group (preferably an arylthio group
having from 6 to 20, more preferably from 6 to 16, and particularly preferably from
6 to 12, carbon atoms, e.g., phenylthio), a sulfonyl group (preferably a sulfonyl
group having from 1 to 20, more preferably from 1 to 16, and particularly preferably
from 1 to 12, carbon atoms, e.g., mesyl, tosyl), a sulfinyl group (preferably a sulfinyl
group having from 1 to 20, more preferably from 1 to 16, and particularly preferably
from 1 to 12, carbon atoms, e.g., methanesulfinyl, benzenesulfinyl), a ureido group
(preferably a ureido group having from 1 to 20, more preferably from 1 to 16, and
particularly preferably from 1 to 12, carbon atoms, e.g., ureido, methylureido, phenylureido),
a phosphoric acid amide group (preferably a phosphoric acid amide group having from
1 to 20, more preferably from 1 to 16, and particularly preferably from 1 to 12, carbon
atoms, e.g., diethylphosphoric acid amide, phenylphosphoric acid amide), a hydroxyl
group, a carboxyl group, a sulfo group, a sulfino group (a sulfinic acid group), a
mercapto group, a halogen atom (e.g., fluorine, chlorine, bromine, iodine), a cyano
group, a nitro group, a hydroxamic acid group, a hydrazino group, and a heterocyclic
group (e.g., imidazolyl, pyridyl, furyl, piperidyl, morpholino). A substituent which
can form a salt with, e.g., an alkali metal, may form a salt. These substituents may
further be substituted. When there are two or more substituents, they may be the same
or different.
[0060] Preferred examples of the substituents represented by R
1, R
2, R
3 and R
4 include an alkyl group, an alkenyl group, an aryl group, an alkoxyl group, an aryloxy
group, an acyl group, an acyloxy group, an alkoxycarbonyl group, an acylamino group,
an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group,
a sulfamoyl group, a carbamoyl group, a ureido group, a phosphoric acid amide group,
a hydroxyl group, a carboxyl group, a sulfo group, a sulfino group, a sulfonyl group,
a halogen atom, a cyano group, a nitro group, and a heterocyclic group. More preferred
groups include an alkyl group, an aryl group, an alkoxyl group, an aryloxy group,
an acyl group, an acylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl
group, a hydroxyl group, a sulfonyl group, a halogen atom, and a cyano group, and
particularly preferred groups include an alkyl group, an aryl group, an alkoxyl group,
and a halogen atom.
[0061] R
1, R
2, R
3 and R
4 each particularly preferably represents a hydrogen atom or the above-exemplified
particularly preferred substituent.
[0062] L
1 and L
2 each represents a linking group. Linking groups represented by L
1 and L
2 are preferably divalent linking groups having from 1 to 6 carbon atoms. Preferred
examples include an alkylene group having from 1 to 6 carbon atoms (e.g., -CH
2-, -CH
2CH
2-), -C=O-, -CONH-, -SO
2NH-, -COO-, -O-, and combinations of them. More preferred are alkylene groups having
from 1 to 3 carbon atoms, and they may further have a substituent.
[0063] n
1 and n
2 each represents 0 or 1, preferably n
1 and n
2 each represents 0. When n
1 and n
2 each represents 1, L
1 and L
2 may be the same or different.
[0064] M represents a hydrogen atom or a counter ion, and k represents a valency of M, and
when M represents a hydrogen atom, k represents 1. Examples of counter ions include
an inorganic or organic ammonium ion (e.g., an ammonium ion, a triethylammonium ion,
a pyridinium ion), an alkali metal ion (e.g., a lithium ion, a sodium ion, a potassium
ion), an alkaline earth metal ion (e.g., a calcium ion, a barium ion, a magnesium
ion) , and other ions (e.g., an aluminum ion, a zinc ion). As counter ions, ionic
polymers, other organic compounds having reverse charge, or a metal complex ion (e.g.,
a hydroxopentaaqua aluminum(III) ion, a tris(2,2'-bipyridine) iron(II) ion) are also
applicable. M may form an inner salt with other substituent in the molecule. Preferred
examples include a sodium ion, a potassium ion, an ammonium ion, a triethylammonium
ion, and a pyridinium ion, and more preferred are a sodium ion, a potassium ion and
an ammonium ion. In the present invention, M preferably represents a counter ion.
When there are two M's, they are in general the same but may be different in certain
cases.
[0066] The compound represented by formula (I) in the present invention can be synthesized
according to the methods described in
Tetrahedron, Vol. 31 (20), pp. 2607 to 2619,
Angewante Chem., Vol. 86(9), p. 349 (1974), and the methods in the literature cited therein. Commercially
available products are also applicable. The addition amount of the compound represented
by formula (I) is preferably from 10
-3 to 10 mol, more preferably from 10
-2 to 1 mol per mol of Ag. The compound represented by formula (I) may be used alone
or in combination of two or more.
[0067] The compound represented by formula (I) may be added to any layer provided on the
same side of the support as the layer containing an organic acid silver salt, e.g.,
an organic acid silver salt-containing layer (an image-recording layer), a photosensitive
layer, an interlayer, and a protective layer, preferably added to an interlayer or
a protective layer.
[0068] The compound represented by formula (I) according to the present invention may be
added in any form, e.g., a solution, a powder, or a solid fine grain dispersion. A
solid fine particle dispersion is prepared using well-known atomizing means, e.g.,
a ball mill, a vibrating ball mill, a sand mill, a colloid mill, a jet mill, a roller
mill, etc. Dispersing aids may be used for solid fine particle dispersion.
[0069] A photothermographic photosensitive material according to the present invention preferably
comprises a photosensitive layer containing a photosensitive silver halide (a catalytically
active amount of a photocatalyst) and a photo-insensitive layer. The photosensitive
layer preferably contains a binder (in general, a synthetic polymer) and a scaly organic
acid silver salt of the present invention. Further, the photosensitive layer preferably
contains a hydrazine compound (a super high contrasting agent) and a tone adjustor
(for controlling silver tone). The photosensitive layer may comprise a plurality of
layers. For example, the photothermographic photosensitive material may be provided
with a high speed-photosensitive layer and a low speed-photosensitive layer with a
view to adjusting gradation. The order of the arrangement of the high speed-photosensitive
layer and the low speed-photosensitive layer is such that the low speed-photosensitive
layer may be arranged at the lower side (nearer to the support) or the high speed-photosensitive
layer may be arranged at the lower side.
[0070] In addition to a layer containing a dye, i.e., a filter layer, and an antihalation
layer, the photo-insensitive layer may be provided with other functional layer such
as a surface protective layer.
[0071] As a support for the photothermographic photosensitive material according to the
present invention, paper, polyethylene-coated paper, polypropylene-coated paper, parchment,
cloth, a sheet or a thin film of a metal (e.g., aluminum, copper, magnesium, zinc),
glass, and glass or plastic films coated with a metal (e.g., a chromium alloy, steel,
silver, gold, platinum) can be used. Transparent plastic films are preferably used
as a support, and examples of preferred plastics include polyalkyl methacrylate (e.g.,
polymethyl methacrylate), polyester (e.g., polyethylene terephthalate (PET)), polyvinyl
acetal, polyamide (e.g., nylon), and cellulose ester (e.g., cellulose nitrate, cellulose
acetate, cellulose acetate propionate, cellulose acetate butyrate). A support preferably
has a thickness of from 90 to 190 µm, more preferably from 150 to 185 µm.
[0072] A support may be covered with a polymer. Examples of polymers which can be used include
polyvinylidene chloride, acrylic acid polymers (e.g., polyacrylonitrile, methyl acrylate),
polymers of unsaturated dicarboxylic acid (e.g., itaconic acid, acrylic acid), carboxymethyl
cellulose and polyacrylamide. Copolymers may also be used. An undercoating layer containing
a polymer may be provided in place of being covered with a polymer.
[0073] The silver halide for use in the present invention is not limited in particular and
any of silver bromide, silver iodide, silver chloride, silver chlorobromide, silver
iodobromide, and silver chloroiodobromide can be used in the present invention. The
distribution of the halogen composition in the grain may be uniform, the halogen composition
may be changed stepwise or may be continuously changed. Silver halide grains having
a core/shell structure can be preferably used. Grain structures are preferably from
a double structure to a quintuple structure. Core/shell grains having a double structure
to a quadruple structure can be more preferably used. Techniques of localizing silver
bromide on the surface of silver chloride or silver chlorobromide grains can preferably
be used.
[0074] The grain size of the silver halide grain is from 0.001 to 0.04 µm, preferably from
0.005 to 0.04 µm. The equivalent-circle diameters obtained with an electron microscope
from the projected areas of the grains are averaged, which is taken as the grain diameter
of the silver halide grain in the present invention.
[0075] The addition amount of the silver halide is preferably from 0.03 to 0.6 g/m
2, more preferably from 0.05 to 0.4 g/m
2, and most preferably from 0.1 to 0.4 g/m
2, as the coating amount per m
2 of the photothermographic material.
[0076] The photosensitive silver halide for use in the present invention can be produced
using the methods well-known in this industry, for example, the methods disclosed
in
Research Disclosure, No. 17029 (June, 1978) and U.S. Patent 3,700,458 can be used. Specifically, silver
halide is produced as a silver halide emulsion by the reaction of silver nitrate and
a soluble halide. Silver halide may be produced by reacting a silver soap with a halogen
ion, and converting the soap part of the silver soap to halogen. Alternatively, a
halogen ion may be added during a silver soap-forming step.
[0077] Silver halide is generally spectrally sensitized before use. Spectral sensitizing
dyes are disclosed in JP-A-60-140335, JP-A-63-159841, JP-A-63-231437, JP-A-63-259651,
JP-A-63-304242, JP-A-63-15245, U.S. Patents 4,639,414, 4,740,455, 4,741,966, 4,751,175,
and 4,835,096.
[0078] The photosensitive layer and the photo-insensitive layer preferably contain a binder.
In general, a colorless and transparent or translucent polymer is used as a binder.
[0079] The effect of the present invention increases when the photosensitive layer is formed
by coating a coating solution in which 30% by weight or more of the solvent is occupied
by water, and then drying, further, when a polymer latex, which is soluble or dispersible
in a water system solvent (water solvent), in particular, having an equilibrium moisture
content at 25°C 60% RH of 2% by weight or less, is used as the main binder of the
photosensitive layer (70% by weight or more, preferably 80% by weight or more of the
total binder of the photosensitive layer). The most preferred polymer of the present
invention is a polymer so prepared that ionic conductivity becomes 2.5 mS/cm or less.
Such a polymer can be produced by a method of subjecting the polymer synthesized to
purifying treatment using a separating function film.
[0080] "A water system solvent" in which the main binder (hereinafter referred to as "the
polymer according to the present invention") of the photosensitive layer of the present
invention is soluble or dispersible as used herein is water or water mixed with a
water-miscible organic solvent in concentration of 70 wt% or less. As water-miscible
organic solvents, alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol,
cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, ethyl
acetate and dimethylformamide can be exemplified.
[0081] The system of a so-called dispersing state in which a polymer is not dissolved thermodynamically
is also called a water system solvent in the present invention.
[0082] "An equilibrium moisture content at 25°C 60% RH" used in the present invention can
be represented as follows with the weight of the polymer in humidity condition equilibrium
at 25°C 60% RH being W1 and the weight of the polymer at 25°C dry state being W0:
[0083] As for the definition and the measuring method of a moisture content, e.g.,
Polymer Engineering, Lecture 14, "Test Method of Polymeric Materials", compiled by Kobunshi-Gakkai, published by
Chijin Shokan Co. Ltd. can be referred to.
[0084] The equilibrium moisture content at 25°C 60% RH of the polymer according to the present
invention is preferably 2 wt% or less, more preferably from 0.01 to 1.5 wt%, and still
more preferably from 0.02 to 1 wt%.
[0085] The polymers according to the present invention are not particularly restricted so
long as they are soluble or dispersible in the above-described water system solvent
and have equilibrium moisture content at 25°C 60% RH of 2 wt% or less. Of these polymers,
polymers which are dispersible in a water system solvent are particularly preferred.
[0086] As examples of dispersion conditions, there are latexes in which fine particles of
solid polymers are dispersed and dispersions in which polymer molecules are dispersed
in a molecular state or with forming micells, and any of these can be preferably used.
[0087] Hydrophobic polymers such as an acrylic resin, a polyester resin, a rubber-based
resin (e.g., an SBR resin), a polyurethane resin, a vinyl chloride resin, a vinyl
acetate resin, a vinylidene chloride resin, and a polyolefin resin can be preferably
used. Polymers may be straight chain, branched or crosslinked polymers. As polymers,
any of homopolymers in which single monomers are polymerized and copolymers in which
two or more monomers are copolymerized can be used. When copolymers are used, any
of random copolymers and block copolymers can be used. The molecular weight of polymers
is from 5,000 to 1,000,000, preferably from 10,000 to 200,000, in number average molecular
weight. If the molecular weight is too small, the mechanical strength of the emulsion
layer is insufficient, while when it is too large, the film-forming property is disadvantageously
deteriorated.
[0088] The polymers according to the present invention comprise the foregoing polymers dispersed
in a water system dispersion medium. "Water system dispersion medium" used herein
means a dispersion medium in which 30 wt% or more of the composition is occupied by
water. As dispersion conditions, any of emulsified dispersion, micell dispersion,
dispersion in which polymers having hydrophilic parts in the molecule are dispersed
in a molecular state can be used but latexes are particularly preferably used.
[0089] Specific examples of preferred polymers are shown below. Inthe following, polymers
are indicated as raw material monomers, the numerical values in parentheses are wt%
and the molecular weights are number average molecular weights.
- P-1:
- Latex comprising MMA (70)-EA (27)-MAA (3) (molecular weight: 37,000)
- P-2:
- Latex comprising MMA (70)-2EHA (20)-St (5)-AA (5) (molecular weight: 40,000)
- P-3:
- Latex comprising St (50)-Bu (47)-MAA (3) (molecular weight: 45,000)
- P-4:
- Latex comprising St (68)-Bu (29)-AA (3) (molecular weight: 60,000)
- P-5:
- Latex comprising St (70)-Bu (27)-IA (3) (molecular weight: 120,000)
- P-6:
- Latex comprising St (75)-Bu (24)-AA (1) (molecular weight: 108,000)
- P-7:
- Latex comprising St (60)-Bu (35)-DVB (3)-MAA (2) (molecular weight: 150,000)
- P-8:
- Latex comprising St (70)-Bu (25)-DVB (2)-AA (3) (molecular weight: 280,000)
- P-9:
- Latex comprising VC (50)-MMA (20)-EA (20)-AN (5)-AA (5) (molecular weight: 80,000)
- P-10:
- Latex comprising VDC (85)-MMA (5)-EA (5)-MAA (5) (molecular weight: 67,000)
- P-11:
- Latex comprising Et (90)-MAA (10) (molecular weight: 12,000)
- P-12:
- Latex comprising St (70)-2EHA (27)-AA (3) (molecular weight: 130,000)
- P-13:
- Latex comprising MMA (63)-EA (35)-AA (2) (molecular weight: 33,000)
[0090] Abbreviations in the above show the following monomers. MMA: methyl methacrylate,
EA: ethyl acrylate, MAA: methacrylic acid, 2EHA: 2-ethylhexyl acrylate, St: styrene,
Bu: butadiene, AA: acrylic acid, DVB: divinylbenzene, VC: vinyl chloride, AN: acrylonitrile,
VDC: vinylidene chloride, Et: ethylene, and IA: itaconic acid.
[0091] The above-described polymers are commercially available and the following polymers
can be used. As examples of acrylic resins, Sebian A-4635, 46583, and 4601 (manufactured
by Daicel Chemical Industries Ltd.), Nipol Lx811, 814, 821, 820, and 857 (manufactured
by Nippon Zeon Co., Ltd.), as examples of polyester resins, FINETEX ES650, 611, 675,
and 850 (manufactured by Dainippon Chemicals and Ink Co., Ltd.), WD-size and WMS (manufactured
by Eastman Chemical Co.), as examples of polyurethane resins, HYDRAN AP10, 20, 30,
and 40 (manufactured by Dainippon Chemicals and Ink Co., Ltd.), as examples of rubber-based
resins, LACSTAR 7310K, 3307B, 4700H, and 7132C (manufactured by Dainippon Chemicals
and Ink Co., Ltd.), Nipol Lx416, 410, 438C, and 2507 (manufactured by Nippon Zeon
Co., Ltd.), as examples of vinyl chloride resins, G351 and G576 (manufactured by Nippon
Zeon Co., Ltd.), as examples of vinylidene chloride resins, L502 and L513 (manufactured
by Asahi Chemical Industry Co., Ltd.), and as examples of olefin resins, Chemipearl
S120 and SA100 (manufactured by Mitsui Petrochemical Industries, Ltd.) can be exemplified.
[0092] These polymers may be used alone as polymer latexes or two or more polymers may be
blended, if necessary.
[0093] Styrene/butadiene copolymer latexes are particularly preferably used in the present
invention. The weight ratio of the styrene monomer unit and the butadiene monomer
unit in styrene/butadiene copolymers is preferably from 40/60 to 95/5. The ratio occupied
by the styrene monomer unit and the butadiene monomer unit in the copolymer is preferably
from 60 to 99 wt%. The preferred molecular weight is the same as described above.
[0094] Preferred styrene/butadiene copolymer latexes which can be used in the present invention
are the foregoing P-3 and P-8 and commercially available products LACSTAR-3307B, 7132C,
and Nipol Lx416.
[0095] Hydrophilic polymers such as gelatin, polyvinyl alcohol, methyl cellulose, and hydroxypropyl
cellulose may be added to the photosensitive layer of the photosensitive material
of the present invention, according to necessity. The addition amount of these hydrophilic
polymers is preferably 30 wt% or less, more preferably 20 wt% or less, based on the
total amount of the binder of the photosensitive layer.
[0096] The photosensitive layer according to the present invention is preferably formed
of polymer latexes. The weight ratio of the total binder/the organic silver salt in
the photosensitive layer is preferably from 1/10 to 10/1, more preferably from 1/5
to 4/1.
[0097] The weight ratio of the total binder/silver halide is preferably from 400 to 5, more
preferably from 200 to 10.
[0098] The total amount of the binder in the photosensitive layer of the present invention
is preferably from 0.2 to 30 g/m
2, more preferably from 1 to 15 g/m
2. The photosensitive layer of the present invention may contain a crosslinking agent
for crosslinking and a surfactant for improving coating property.
[0099] The solvent for the coating solution of the photosensitive layer of the photosensitive
material of the present invention (solvent and dispersion medium are briefly expressed
as solvent collectively) is a water system solvent containing 30 wt% or more of water.
As components other than water, water-miscible organic solvents such as methyl alcohol,
ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide
and ethyl acetate may be arbitrarily used in the coating solution. The water content
in the solvent of the coating solution is preferably 50% by weight or more, more preferably
70% by weight or more. Preferred examples of the compositions of the solvent include,
in addition to water, water/methyl alcohol = 90/10 (wt%), water/methyl alcohol = 70/30,
water/methyl alcohol/ dimethylformamide = 80/15/5, water/methyl alcohol/ethyl cellosolve
= 85/10/5, water/methyl alcohol/isopropyl alcohol = 85/10/5, etc.
[0100] It is preferred for the photosensitive layer or the photo-insensitive layer to further
contain a super high contrasting agent. When the photothermographic (photosensitive)
material is used in the field of a photograph for printing, the reproduction of a
continuous gradation image by dots and a line image is important. The reproduction
of a dot image and a line image can be removed by using a super high contrast-increasing
agent. As a super high contrast-increasing agent, hydrazine compounds, quaternary
ammonium compounds or acrylonitrile compounds (e.g., disclosed in U.S. Patent 5,545,515)
can be used. Hydrazine compounds are particularly preferably used.
[0101] Hydrazine compounds include a compound in which hydrazine (H
2N-NH
2) and at least one of hydrogen atoms are substituted. As the substituent, an aliphatic,
aromatic or heterocyclic group is directly bonded to the nitrogen atom of the hydrazine,
or an aliphatic, aromatic or heterocyclic group is bonded to the nitrogen atom of
the hydrazine via a linking group. Examples of the linking groups include -CO-, -CS-,
-SO
2-, -POR- (R represents an aliphatic, aromatic or heterocyclic group), -CNH- and combinations
of these.
[0102] Hydrazine compounds are disclosed in U.S. Patents 5,464,738, 5,496,695, 5,512,411,
5,536,622, JP-B-6-77138 (the term "JP-B" as used herein means an "examined Japanese
patent publication"), JP-B-6-93082, JP-A-6-230497, JP-A-6-289520, JP-A-6-313951, JP-A-7-5610,
JP-A-7-77783, and JP-A-7-104426.
[0103] A hydrazine compound can be dissolved in an appropriate organic solvent and then
added to a coating solution for a photosensitive layer. Examples of organic solvents
include alcohols (e.g., methanol, ethanol, propanol, fluorinated alcohol), ketones
(e.g., acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, and methyl
cellosolve. A hydrazine compound may be dissolved in an oily (auxiliary) solvent and
the solution may be emulsified in a coating solution. Examples of oily (auxiliary)
solvents include dibutyl phthalate, tricresyl phosphate, glyceryl triacetate, diethyl
phthalate, ethyl acetate and cyclohexanone. Further, a solid dispersion of a hydrazine
compound may be added to a coating solution. Dispersion of a hydrazine compound can
be performed using well-known dispersing machines such as a ball mill, a colloid mill,
Manton Gauling, microfluidizer, or an ultrasonic disperser.
[0104] The addition amount of a super high contrasting agent is preferably from 1×10
-6 to 1×10
-2 mol, more preferably from 1×10
-5 to 5×10
-3 mol, and most preferably from 2×10
-5 to 5×10
-3 mol, per mol of the silver halide.
[0105] In addition to a super high contrast-increasing agent, a high contrast accelerating
agent may be used in the present invention. Examples of high contrast accelerating
agents include an amine compound (e.g., disclosed in U.S. Patent 5,545,506), a hydroxamic
acid (e.g., disclosed in U.S. Patent 5,545,507), acrylonitriles (e.g., disclosed in
U.S. Patent 5,545,507), and a hydrazine compound (e.g., disclosed in U.S. Patent 5,558,983).
[0106] It is preferred for a photosensitive layer or a photo-insensitive layer to contain
a tone adjusting agent (a toner). A tone adjusting agent is described in
Research Disclosure, No. 17029.
[0107] Examples of tone adjusting agents include imides (e.g., phthalimide); cyclic imides
(e.g., succinimide); pyrazolin-5-ones (e.g., 3-phenyl-2-pyrazolin-5-one, 1-phenylurazol);
quinazolinone (e.g., quinazolinone, 2,4-thiazolidinedione); naphthalimides (e.g.,
N-hydroxy-1,8-naphthalimide); cobalt complexes (e.g., cobalt hexaminetrifluoroacetate);
mercaptans (e.g., 3-mercapto-1,2,4-triazole); N-(aminomethyl)aryldicarboxyimides (e.g.,
N-(dimethylaminomethyl)phthalimide); blocked pyrazoles (e.g., N,N'-hexamethylene-1-carbamoyl-3,5-dimethylpyrazole);
combinations of isothiuronium derivatives (e.g., 1,8-(3,6-dioxaoctane)bis(isothiuroniumtrifluoroacetate)
with photo-bleaching agent (e.g., 2-tribromomethylsulfonyl)benzothiazole); merocyanine
dyes (e.g., 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene)-1-methylethylidene]-2-thio-2,4-oxazolidinedione);
phthalazinone compounds and metal salts thereof (e.g., phthalazinone, 4-(1-naphthyl)phthalazinone,
6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, 2,3-dihydro-1,4-phthalazinedione,
8-methylphthalzine); combinations of phthalazinone compounds and sulfinic acid derivatives
(e.g., sodium benzenesulfinate); combinations of phthalazinone compounds and sulfonic
acid derivatives (e.g., sodium p-toluenesulfonate); phthalazine and derivatives thereof
(e.g., phthalazine, 6-isopropylphthalazine, 6-methylphthalazine); combinations of
phthalazines and phthalic acids; combinations of phthalazines or phthalazine adducts
with dicarboxylic acids (e.g., preferablyo-phenylenicacid) or anhydrides thereof (e.g.,
maleic anhydride, phthalic acid, 2,3-naphthalenedicarboxylic acid, phthalic anhydride,
4-methylphthalic acid, 4-nitrophthalic acid, tetrachlorophthalic anhydride); quinazolinediones;
benzoxazine; naphthooxazine derivatives; benzoxazine-2,4-diones (e.g., 1,3-benzoxazine-2,4-dione);
pyrimidines, asymmetric triazines (e.g., 2,4-dihydroxypyrimidine); tetraazapentalene
derivatives (e.g., 3,6-dimercapto-1,4-diphenyl-1H,4H-2,3a,5,6a-tetraazapentalene).
Of these compounds, phthalazines are particularly preferred.
[0108] Tone adjusting agents are preferably contained in the surface of a photosensitive
layer in an amount of from 0.1 to 50 mol%, more preferably from 0.5 to 20 mol%, per
mol of the silver.
[0109] An antifoggant may be added to a photosensitive layer or a photo-insensitive layer
(preferably a photosensitive layer). As antifoggants, non-mercury compounds (e.g.,
those disclosed in U.S. Patents 3,874,946, 4,546,075, 4,452,885, 4,756,999, 5,028,523,
British Patent Application Nos. 92,221,383.4, 9,300,147.7, 9,311,790.1, and JP-A-59-57234)
are preferably used in the present invention rather than mercury compounds (e.g.,
disclosed in U.S. Patent 3,589,903).
[0110] Particularly preferred antifoggants are heterocyclic compounds having a halogen (e.g.,
F. Cl. Br, I)-substituted methyl group.
[0111] It is preferred to use polyvinyl alcohol (PVA) in the photothermographic material,
in particular, the protective layer of photothermographic (photosensitive) material,
according to the present invention. Examples of PVA which can be used in the present
invention are shown below.
Examples of Completely Saponified Products
[0112]
PVA-105 [polyvinyl alcohol (PVA) content: 94.0 wt% or more, saponification degree:
98.5 ± 0.5 mol%, sodium acetate content: 1.5 wt% or less, volatile content: 5.0 wt%
or less, viscosity (4 wt%, 20°C): 5.6 ± 0.4 CPS].
PVA-110 [PVA content: 94.0 wt%, saponification degree: 98.5 ± 0.5 mol%, sodium acetate
content: 1.5 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 11.0 ± 0.8 CPS].
PVA-117 [PVA content: 94.0 wt%, saponification degree: 98.5 ± 0.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 28.0 ± 3.0 CPS].
PVA-117H [PVA content: 93.5 wt%, saponification degree: 99.6 ± 0.3 mol%, sodium acetate
content: 1.85 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 29.0 ± 3.0
CPS].
PVA-120 [PVA content: 94.0 wt%, saponification degree: 98.5 ± 0.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 39.5 ± 4.5 CPS].
PVA-124 [PVA content: 94.0 wt%, saponification degree: 98.5 ± 0.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 60.0 ± 6.0 CPS].
PVA-124H [PVA content: 93.5 wt%, saponification degree: 99.6 ± 0.3 mol%, sodium acetate
content: 1.85 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 61.0 ± 6.0
CPS].
PVA-CS [PVA content: 94.0 wt%, saponification degree: 97.5 ± 0.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 27.5 ± 3.0 CPS].
PVA-CST [PVA content: 94.0 wt%, saponification degree: 96.0 ± 0.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 27.0 ± 3.0 CPS].
PVA-HC [PVA content: 90.0 wt%, saponification degree: 99.85 mol% or more, sodium acetate
content: 2.5 wt%, volatile content: 8.5 wt%, viscosity (4 wt%, 20°C): 25.0 ± 3.5 CPS],
etc. (All of the above products are manufactured by Kuraray Co., Ltd.)
Examples of Partially Saponified Products
[0113]
PVA-203 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 3.4 ± 0.2 CPS].
PVA-204 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 3.9 ± 0.3 CPS].
PVA-205 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 5.0 ± 0.4 CPS].
PVA-210 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 9.0 ± 1.0 CPS].
PVA-217 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 22.5 ± 2.0 CPS].
PVA-220 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 30.0 ± 3.0 CPS].
PVA-224 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 44.0 ± 4.0 CPS].
PVA-228 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 65.0 ± 5.0 CPS].
PVA-235 [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 95.0 ± 15.0
CPS].
PVA-217EE [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 23.0 ± 3.0 CPS].
PVA-217E [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 23.0 ± 3.0 CPS].
PVA-220E [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 31.0 ± 4.0 CPS].
PVA-224E [PVA content: 94.0 wt%, saponification degree: 88.0 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 45.0 ± 5.0 CPS].
PVA-403 [PVA content: 94.0 wt%, saponification degree: 80.0 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 3.1 ± 0.3 CPS].
PVA-405 [PVA content: 94.0 wt%, saponification degree: 81.5 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 4.8 ± 0.4 CPS].
PVA-420 [PVA content: 94.0 wt%, saponification degree: 79.5 ± 1.5 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%].
PVA-613 [PVA content: 94.0 wt%, saponification degree: 93.5 ± 1.0 mol%, sodium acetate
content: 1.0 wt%, volatile content: 5.0 wt%, viscosity (4 wt%, 20°C): 16.5 ± 2.0 CPS].
L-8 [PVA content: 96.0 wt%, saponification degree: 71.0 ± 1.5mol%, sodium acetate
content: 1.0 wt% (ash content), volatile content:
3.0 wt%, viscosity (4 wt%, 20°C): 5.4 ± 0.4 CPS], etc. (All of the above products
are manufactured by Kuraray Co., Ltd.)
[0114] The above measured values are obtained according to JIS K-6726-1977.
[0115] Modified polyvinyl alcohols described in Koichi Nagano et al.,
Poval, published by Kobunshi-kankoKai can be used in the present invention. Those modified
with a cation, an anion, an -SH compound, an alkylthio compound and a silanol compound
can be used.
[0116] There can be exemplified as modified polyvinyl alcohol (modified PVA), as C polymer,
C-118, C-318, C-318-2A, and C-506 (manufactured by Kuraray Co., Ltd.).
As HL polymer, HL-12E, HL-1203 (manufactured by Kuraray Co., Ltd.).
As HM polymer, HM-03 and HM-N-03 (manufactured by Kuraray Co., Ltd.).
As K polymer, KL-118, KL-318, KL-506, KM-118T and KM-618 (manufactured by Kuraray
Co., Ltd.).
As M polymer, M-115 (manufactured by Kuraray Co., Ltd.).
As MPpolymer, MP-102, MP-202, and MP-203 (manufactured by Kuraray Co., Ltd.).
As R polymer, R-1130, R-2105 and R-2130 (manufactured by Kuraray Co., Ltd.).
As V polymer, V-2250 (manufactured by Kuraray Co., Ltd.).
[0117] The coating amount of polyvinyl alcohol of the protective layer (per one layer) is
preferably from 0.3 to 4.0 g/m
2, more preferably from 0.3 to 2.0 g/m
2 per m
2 of the support.
[0118] The photothermographic material, in particular, the protective layer of the photothermographic
(photosensitive) material, according to the present invention preferably contains
a matting agent. Matting agents in general comprise fine particles of water-insoluble
organic or inorganic compounds. Optional matting agents can be used in the present
invention. Organic matting agents disclosed in U.S. Patents 1,939,213, 2,701,245,
2,322,037, 3,262,782, 3,539,344, and 3,767,448, and inorganic matting agents disclosed
in U.S. Patents 1,260,772, 2,192,241, 3,257,206, 3,370,951, 3,523,022 and 3,769,020
are well-known in this industry and can be used in the present invention. As specific
examples of organic compounds which can be used as matting agents, examples of water-dispersible
vinyl polymers include polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile,
acrylonitrile-α-methylstyrene copolymers, polystyrene, styrene-divinylbenzene copolymers,
polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples
of cellulose derivatives include methyl cellulose, cellulose acetate, cellulose acetate
propionate, etc., examples of starch derivatives include carboxyl starch, carboxynitrophenyl
starch, urea-formaldehyde-starch reaction products, etc., hardened gelatin treated
with well-known hardening agents and hardened gelatin as microencapsulated hollow
particles by coacervation hardening can be preferably used. As examples of inorganic
compounds, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium
sulfate, calcium carbonate, silver chloride and silver bromide desensitized by a well-known
method, glass, and diatomaceous earth can be preferably used. These matting agents
can be mixed with different kinds of substances, if necessary.
[0119] In the present invention, matting agents having a particle size of from 2 to 6 µm
can be preferably used. The particle size distribution of the matting agent may be
broad or narrow. On the other hand, as matting agents largely affect the haze of the
photosensitive material and the surface gloss, it is desired to adjust particle size,
particle shape and particle size distribution to a necessary condition when matting
agents are prepared or by mixing a plurality of matting agents.
[0120] The equivalent-circle diameters obtained with an electron microscope from the projected
areas of the particles are averaged, which is taken as the particle diameter of the
matting agent in the present invention.
[0121] The coating amount of the matting agent is from 1 to 400 mg/m
2, more preferably from 5 to 300 mg/m
2, and it is particularly preferred that the coating amount of the matting agent having
a particle size of 4 µm or more is from 5 to 150 mg/m
2.
[0122] When a matting agent is contained in the layer on the surface side of an image-recording
layer or a photosensitive layer, a protective layer is optimal. A protective layer
may comprise two layers, if necessary. By selecting the layers to contain an additive,
a film pH adjusting agent, an electrostatic charge adjusting agent, an ultraviolet
absorber, a sliding agent and a surfactant which participate in development, it is
possible to design so as to reconcile a coating property and production suitability
with image performance. It is preferred for the outermost protective layer to contain
a fluorine-based surfactant together with a matting agent. As fluorine-based surfactants,
fluorine-based high molecular surfactants disclosed in JP-A-62-170950 and U.S. Patent
5,380,644, fluorine-based surfactants disclosed in JP-A-60-244945 and JP-A-63-188135
can be exemplified.
[0123] In the present invention, it is preferred that a matting agent is contained in the
outermost protective layer.
[0124] A matting agent may be contained in a backing layer, and in this case the layer to
contain a matting agent is preferably not the outermost layer on the back surface
side.
[0125] A hardening agent may be used in each of an image-recording layer (preferably a photosensitive
layer), a protective layer, and a backing layer. Examples of hardening agents are
described in T.H. James,
The Theory of the Photographic Process, the 4th Ed., pp. 77 to 87, Macmillan Publishing Co., Inc. (1977), and polyvalent
metal ions described on p. 78 of the above literature, polyisocyanates disclosed in
U.S. Patent 4,281,060 and JP-A-6-208193, epoxy compounds disclosed in U.S. Patent
4,791,042, and vinyl sulfone compounds disclosed in JP-A-62-89048 are preferably used
in the present invention.
[0126] Any adhesion preventing material may be used as the surface protective layer according
to the present invention. Examples of adhesion preventing materials include waxes,
silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-styrene,
styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose
propionate, and mixtures of these. Further, the surface protective layer of the present
invention may contain a crosslinking agent for crosslinking and a surfactant for improving
a coating property.
[0127] The image-recording layer or the protective layer of the image-recording layer according
to the present invention can contain light absorbing substances or filter dyes as
disclosed in U.S. Patents 3,253,921, 2,274,782, 2,527,583 and 2,956,879. Further,
dyes can be mordanted as disclosed in U.S. Patent 3,282,699.
[0128] The image-recording layer or the protective layer of the image-recording layer according
to the present invention can contain a matting agent, e.g., starch, titanium dioxide,
zinc oxide, silica, or polymer beads containing beads disclosed in U.S. Patents 2,992,101
and 2,701,245. The matting degree of the emulsion surface is not particularly limited
so long as white-spot unevenness does not occur, but Beck's smoothness is preferably
from 200 to 10,000 seconds, particularly preferably from 300 to 10,000 seconds.
[0129] The photothermographic (photosensitive) material according to the present invention
is preferably a mono-sheet type material (a type capable of forming an image on the
photothermographic (photosensitive) material not using other sheet, e.g., an image-receiving
material).
[0130] The photothermographic (photosensitive) material according to the present invention
may further contain a surfactant, an antioxidant, a stabilizer, a plasticizer, an
ultraviolet absorber, or a coating aid. Various additives are added to either a photosensitive
layer or a photo-insensitive layer. With respect to the addition of these additives,
WO 98/36322, EP-A-803764, JP-A-10-186567 and JP-A-10-18568 can be referred to.
[0131] The photosensitive layer of the present invention can contain, as a plasticizer and
a lubricant, polyhydric alcohols (e.g., glycerins and diols disclosed in U.S. Patent
2,960,404), fatty acids or fatty acid esters disclosed in U.S. Patents 2,588,765 and
3,121,060, and silicone resins disclosed in British Patent 955,061.
[0132] It is preferred in the photothermographic (photosensitive) material of the present
invention that the photo-insensitive layer contains a decoloring dye and a base precursor
to function as a filter layer or an antihalation layer. A photothermographic (photosensitive)
material generally has photo-insensitive layers in addition to photosensitive layers.
Photo-insensitive layers can be classified from the arrangement to (1) a protective
layer provided on a photosensitive layer (farther from a support), (2) an interlayer
provided between a plurality of photosensitive layers or between a photosensitive
layer and a protective layer, (3) an undercoating layer provided between a photosensitive
layer and a support, and (4) a backing layer provided on the opposite side to a photosensitive
layer. A filter layer is provided in a photosensitive material as a layer of (1) or
(2). An antihalation layer is provided in a photosensitive material as a layer of
(3) or (4).
[0133] A decoloring dye and a base precursor are preferably added to the same photo-insensitive
layer. They may be added to two adjacent photo-insensitive layers separately. Further,
a barrier layer may be provided between two photo-insensitive layers. In the present
invention, "a layer contains a decoloring dye and a base precursor" includes the case
in which a plurality of adjacent layers contain a decoloring dye and a base precursor
separately.
[0134] A decoloring dye can be added to the coating solution of a photo-insensitive layer
as a solution, an emulsion, a solid fine particle dispersion, or a polymer impregnated
product. A dye can also be added to a photo-insensitive layer using a polymer mordant.
These addition methods are the same as the methods employed for adding dyes to general
photothermographic (photosensitive) materials. Latexes used in polymer impregnated
products are disclosed in U.S. Patent 4,199,363, German Patent Publication Nos. 2,541,274
and 2,541,230, EP 029104, and JP-B-53-41091. With respect to the emulsifying method
for adding a dye to a solution containing a dissolved polymer is disclosed in 88/00723.
[0135] The addition amount of a decoloring dye is determined by the purpose of the dye.
In general, a decoloring dye is used in the amount giving optical density (absorbance)
exceeding 0.1 when measured at objective wavelength. Optical density is preferably
from 0.2 to 2. The addition amount of a dye for obtaining such optical density is
in general from about 0.001 to about 1 g/m
2, preferably from about 0.005 to about 0.8 g/m
2, and particularly preferably from about 0.01 to about 0.2 g/m
2.
[0136] Decoloration of dyes according to the present invention results in the reduction
of optical density to 0.1 or less. Two or more kinds of decoloring dyes may be used
in combination in a thermal decoloring type recording material and a photothermographic
(photosensitive) material. Two or more kinds of base precursors may also be used in
combination.
[0137] The photosensitive material according to the present invention may be provided with
an antistatic layer or an electrically conductive layer, e.g., layers containing soluble
salts (e.g., chloride, nitrate), metal deposited layers, layers containing ionic polymers
disclosed in U.S. Patents 2,861,056 and 3,206,312, and insoluble inorganic salts disclosed
in U.S. Patent 3,428,451.
[0138] The method for obtaining a color image with the photothermographic (photosensitive)
material according to the present invention is disclosed in JP-A-7-13295, from p.
10, left column, 1. 43 to p. 11, left column, 1. 40. Color dye image stabilzers are
disclosed in British Patent 1,326,889, U.S. Patents 3,432,300, 3,698,909, 3,574,627,
3,573,050, 3,764,337 and 4,042,394.
[0139] The photothermographic material, in particular photothermographic (photosensitive)
material, according to the present invention may be coated by any method. Specifically,
extrusion coating, slide coating, curtain coating, immersion coating, knife coating,
flow coating, and various coating methods including extrusion coating using hoppers
disclosed in U.S. Patent 2,681,294 can be used. Extrusion coating and slide coating
described in Stephen F. Kistler, Peter M. Schweizer,
Liquid Film Coating, pp. 399 to 536, Chapman & Hall Co. (1997) are preferably used, particularly preferably
slide coating is used. Examples of the shapes of slide coaters for use in slide coating
are described in
ibid., p. 427, Figure 11b.1. Two or more layers can be coated simultaneously by the methods
described in
ibid., pp. 399 to 536, U.S. Patent 2,761,791 and British Patent 837,095, if desired. Simultaneous
coating methods are preferably used.
[0140] Surfactants may be used in the present invention for the purpose of improving coating
property and electric charge. Any surfactant can be used arbitrarily, e.g., nonionic,
anionic, cationic and fluorine-based surfactants. Specifically, fluorine-based high
molecular surfactants disclosed in JP-A-62-170950 and U.S. Patent 5,380,644, fluorine-based
surfactants disclosed in JP-A-60-244945 and JP-A-63-188135, polysiloxane-based surfactants
disclosed in U.S. Patent 3,885,965, and polyalkylene oxide and anionic surfactants
disclosed in JP-A-6-301140 can be exemplified.
[0141] In a photothermographic (photosensitive) material, an image is formed by heating
after image exposure. A black tone silver image is formed by this heat development.
Image exposure is preferably performed with a laser. The heating temperature of the
heat development is preferably from 80 to 250°C, more preferably from 100 to 200°C.
Heating period of time is generally from 1 second to 2 minutes.
[0142] A plate heater system is preferably used as the heat developing method. Plate heater
systems disclosed in JP-A-11-133572 and Japanese Patent Application No. 10-177610
are preferred, which are methods using a heat developing apparatus to obtain a visible
image by making a photothermographic (photosensitive) material, in which a latent
image has been formed, contact with a heating means at a heat development part. The
foregoing heating means comprises a plate heater, and a plurality of pressing rollers
are arranged along one surface of the plate heater vis-a-vis with the plate heater.
Heat development is performed by passing the foregoing photothermographic (photosensitive)
material between the above pressing rollers and the plate heater.
[0143] As a heating method in heat development process, embodiments shown in Figs. 1 and
2 can be exemplified.
[0144] A photothermographic (photosensitive) material transported to an image exposure part
is scanning-exposed by laser beams etc. and transported to heat developing part 18
by means of transporting rollers etc. after a latent image has been formed on the
photothermographic (photosensitive) material. During transportation, dusts on the
back and front surfaces of the material are removed by a dust removing roller.
[0145] As shown in Fig. 1, heat developing part 18 is a part to make a latent image a visible
image by heat development by heating the photothermographic (photosensitive) material.
The present invention is characterized in that heat developing part 18 comprises plate
heater 120 and a plurality of pressing rollers 122 arranged vis-a-vis with plate heater
120.
[0146] Plate heater 120 is a plate-like heating member encasing a heating unit such as nichrome
wire laid down in a planar state, which is maintained at developing temperature of
the photothermographic (photosensitive) material. The surface of plate heater 120
is preferably coated with fluororesins or stuck with a fluororesin sheet for the purpose
of lessening a friction coefficient or giving abrasion resistance.
[0147] The volatile content of the photothermographic (photosensitive) material is evaporated
by heating during heat development, as a result, the photothermographic photosensitive
material rises from plate heater 120, and the contact of the photothermographic (photosensitive)
material with plate heater 120 sometimes becomes uneven. Therefore, it is also preferred
to form minute concavities and convexities on the surface of plate heater 120 to dissipate
this vapor.
[0148] It is also preferred to provide temperature gradient so as to make the temperature
of both ends of plate heater 120 higher than the temperature of other parts for compensating
for the temperature reduction due to heat dissipation at both ends.
[0149] Pressing rollers 122 are arranged with a prescribed pitch being in contact with one
surface of plate heater 120 with a distance smaller than the thickness of the photothermographic
(photosensitive) material along the entire length of the transporting direction of
plate heater 120, and these pressing rollers 122 and plate heater 120 constitute the
path of the photothermographic (photosensitive) material. Making the distance of the
path of the photothermographic (photosensitive) material smaller than the thickness
of the photothermographic (photosensitive) material can prevent the photothermographic
(photosensitive) material from buckling. Feeding rollers 126 for feeding the photothermographic
(photosensitive) material to heat developing part 18 from the direction of the indicated
arrow and discharging rollers 128 for discharging the photothermographic (photosensitive)
material to the direction of the indicated arrow after heat development are arranged
at both ends of the path of the photothermographic (photosensitive) material.
[0150] Further, it is preferred to provide heat insulating cover 125 for heat insulation
on the surface side of pressing rollers 122 opposite to plate heater 120.
[0151] When the photothermographic (photosensitive) material is transported, if the tip
of the photothermographic (photosensitive) material strikes against pressing roller
122, the photothermographic (photosensitive) material stops a moment. At that time,
if pressing rollers 122 are arranged with the same pitch, the same part of the photothermographic
(photosensitive) material stops at every pressing roller 122 and that part of the
photothermographic (photosensitive) material is pressed against plate heater 120 for
longer time, which sometimes results in generation of streaky uneven development stretching
in the width direction. Therefore, it is preferred to make pitch of each pressing
roller 122 uneven.
[0152] As shown in Fig. 2, the constitution of heat developing part 18 may also be such
that driving roller 130 is arranged in contact with each pressing roller 122 with
making the enveloping surface of each pressing roller 122 the circumferential surface
and each pressing roller 122 is rotated by the rotation of driving roller 130.
[0153] In the above explanation, plate heater 120 may also comprise a plate member comprising
a heat conductor and a heat source arranged on the side of the plate member opposite
to the heating side of the photothermographic (photosensitive) material.
[0154] When a photothermographic material does not contain a photosensitive silver halide,
heat development is performed according to an ordinary method.
[0155] The present invention is described in detail with reference to the examples, but
the present invention should not be construed as being limited thereto.
EXAMPLE I-1
Preparation of Silver Halide Grain Emulsion 1
[0156] To 1,421 ml of distilled water were added 6.7 ml of a 1 wt% potassium bromide solution,
8.2 ml of 1 N nitric acid and 21.8 g of phthalated gelatin. This mixed solution was
stirred in a titanium-coated stainless reaction vessel with maintaining the temperature
at 25°C. Solution al (37.04 g of silver nitrate was diluted with distilled water to
make 159 ml) and solution b1 (32.6 g of potassium bromide was diluted with distilled
water to make 200 ml) were prepared. The entire amount of solution al was added to
the reaction vessel at a constant flow rate by a controlled double jet method with
maintaining pAg at 8.1 over 1 minute (solution b1 was added by a controlled double
jet method) . Then, 30 ml of a 3.5 wt% hydrogen peroxide aqueous solution was added,
further, 33.6 ml of a 3 wt% aqueous solution of benzimidazole was added thereto. Solution
a2 (solution al was again diluted with distilled water to make 317.5 ml) and solution
b2 (dipotassium hexachloroiridate was dissolved in solution b1 so as to make the concentration
1 × 10
-4 mol per mol of the silver, diluted with distilled water to reach the final volume
of 2 times of solution b1, i.e., 400 ml) were prepared. The entire amount of solution
a2 was added to the reaction vessel at a constant flow rate by a controlled double
jet method with maintaining pAg at 8.1 over 10 minutes (solution b2 was added by a
controlled double jet method). Then, 50 ml of a 0.5 wt% methanol solution of 2-mercapto-5-methylbenzimidazole
was added, further, pAg was lowered to 7.5 with silver nitrate, pH was adjusted with
1 N sulfuric acid to 3.8, and stirring was stopped. The reaction solution was subjected
to precipitation, desalting and washing processes, 3.5 g of deionized gelatin was
added, and then 1 N sodium hydroxide was added to adjust pH to 6.0 and pAg to 8.2,
thereby a silver halide dispersion was obtained.
[0157] The grains in the thus-prepared silver halide emulsion were pure silver bromide grains
having an average equivalent-sphere diameter of 0.031 µm and equivalent-sphere diameter
variation coefficient of 11%. Grain size was the average of 1,000 grains obtained
by electron microscope. {100} face ratio of this grain was 85% according to the Kubelka-Munk
method.
[0158] The temperature of the above emulsion was raised to 45°C with stirring, then 5 ml
of a 0.5 wt% methanol solution of N,N'-dihydroxy-N",N"-diethylmelamine and 5 ml of
a 3.5 wt% methanol solution of phenoxyethanol were added thereto, and 1 minute after,
3×10
-5 mol per mol of the silver of sodium benzenethiosulfonate was added. Further 2 minutes
after, a solid dispersion of spectral sensitizing dye 1 (an aqueous gelatin solution)
was added in an amount of 5×10
-3 mol per mol of the silver, and further 2 minutes after, 5×10
-5 mol per mol of the silver of a tellurium compound was added and the reaction solution
was subjected to ripening for 50 minutes. Immediately before completion of ripening,
2-mercapto-5-methylbenzimidazole in an amount of 1×10
-3 mol, and mercapto compound 1 in an amount of 1.1×10
-3 mol, each per mol of the silver, were added to the reaction solution. The temperature
was lowered to 32°C. Thus, silver halide grain emulsion 1 were prepared.
Preparation of Silver Halide Grain Emulsion 2
[0159] Phthalated gelatin (22 g) and 30 mg of potassium bromide were dissolved in 700 ml
of water, pH was adjusted to 5.0 at 35°C. An aqueous solution (159 ml) containing
18.6 g of silver nitrate and 0.9 g of ammonium nitrate and an aqueous solution containing
potassium bromide and potassium iodide in molar ratio of 92/8 were added to the foregoing
solution by a controlled double jet method over 10 minutes with maintaining pAg at
7.7. Subsequently, 476 ml of an aqueous solution containing 55.4 g of silver nitrate
and 2 g of ammonium nitrate and an aqueous solution containing 1×10
-5 mol/liter of dipotassium hexachloroiridate and 1 mo/liter of potassium bromide were
added to the foregoing solution by a controlled double jet method over 30 minutes
with maintaining pAg at 7.7. Subsequently, 1 g of 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene
was added thereto, pH was lowered and the reaction solution was subjected to coagulative
precipitation, and desalted. Then, 0.1 g of phenoxyethanol was added to adjust pH
to 5.9 and pAg to 8.2, thereby the formation of silver iodobromide grains was terminated.
The thus-obtained silver halide grains were cubic grains having an iodine content
at core part: 8 mol%, average: 2 mol%, an average grain size of 0.005 µm, a variation
coefficient of the projected area diameter of 8%, and {100} face ratio of 88%.
[0160] The temperature of the thus-obtained silver halide grains was raised to 60°C. Sodium
thiosulfate (85 µmol), 1.1×10
-5 mol of 2,3,4,5,6-pentafluorophenyldiphenylphosphineselenide, 1.5×10
-5 mol of a tellurium compound, 3.5×10
-8 mol of chloroauric acid, and 2.7×10
-4 mol of thiocyanic acid, each per mol of the silver, were added to the above silver
halide grains and ripened for 120 minutes, then quenched to 40°C. Spectral sensitizing
dye 1 in an amount of 1×10
-4 mol and 2-mercapto-5-methylbenzimidazole in an amount of 5×10
-4 mol were added thereto, and then the solution was quenched to 30°C, thereby silver
halide grain emulsion 2 was obtained.
Preparation of Scaly Fatty Acid Silver Salt
[0161] Behenic acid (87.6 g) (manufactured by Henkel Co., trade name: Edenor C22-85R), 423
ml of distilled water, 49.2 ml of an aqueous solution containing 5 N NaOH, and 120
ml of tert-butanol were mixed, and the mixture was subjected to reaction for 1 hour
at 75°C, thereby a sodium behenate solution was obtained. Apart from the sodium behenate
solution, 206.2 ml of an aqueous solution containing 40.4 g of silver nitrate (pH
4.0) was prepared and maintained at 10°C. A reaction vessel containing 635 ml of distilled
water and 30 ml of tert-butanol was maintained at 30°C, with stirring the content
in the reaction vessel, the entire amount of the above sodium behenate solution and
the entire amount of the aqueous silver nitrate solution were added to the reaction
vessel at a constant flow rate over 62 minutes and 10 seconds and 60 minutes, respectively,
in such a manner that only the aqueous silver nitrate solution was added from the
start of the addition, 7 minutes and 20 seconds after the start of the addition of
the aqueous silver nitrate solution, the addition of the sodium behenate solution
was started, and only the sodium behenate solution was added for 9 minutes and 30
seconds after the termination of the addition of the aqueous silver nitrate solution.
The temperature in the reaction vessel was maintained at 30°C and the outer temperature
was controlled so as not to increase the temperature. The piping of the addition system
of the sodium behenate solution was warmed by a steamed jacket method, and steam aperture
was adjusted so that the solution temperature at the outlet of the addition nozzle
tip became 75°C. The piping of the addition system of the aqueous silver nitrate solution
was warmed by circulating chilled water in the outer pipe of the double pipe. The
positions where the sodium behenate solution and the aqueous silver nitrate solution
were added were arranged symmetrically with the stirring axle between, and the height
of the position was adjusted so as not to touch the reaction solution.
[0162] After the addition of the sodium behenate solution was finished, the reaction solution
was stirred at the same temperature for 20 minutes and allowed to stand to lower the
temperature to 25°C. The solid content was then filtered by suction. The solid content
was washed with water until the conductivity of the filtrate reached 30 µS/cm. Thus,
a fatty acid silver salt was obtained. The solid content obtained was not dried and
stored as a wet cake.
[0163] The shape of the obtained silver behenate particles was evaluated with an electron
microscope. The obtained silver behenate particles were scaly crystals having a =
0.14 µm, b = 0.4 µm, and c = 0.6 µm, on average, and variation coefficient of the
average equivalent-sphere diameter of 15%.
[0164] Polyvinyl alcohol (trade name: PVA-217) (7.4 g) and water were added to the wet cake
of the amount corresponding to 100 g of dried solid content to make the entire amount
385 g, and then preliminarily dispersed in a homomixer.
[0165] The preliminarily dispersed starting solution was treated three times using a disperser
(trade name: Micro-fluidizer M-110S-EH equipped with G10Z interaction chamber, manufactured
by Micro Fluidex International Corp.). Pressure of the disperser was adjusted to 1,750
kg/cm
2. Thus, silver behenate dispersion was obtained. Cooling operation was performed by
installing coiled heat exchangers respectively before and after the interaction chamber
and setting the desired temperature of dispersion by adjusting the temperature of
the cooling medium.
Preparation of Acicular Fatty Acid Silver Salt (comparison)
[0166] While stirring 43.8 g of behenic acid (manufactured by Henkel Co., trade name: Edenor
C22-85R), 730 ml of distilled water, and 60 ml of tert-butanol at 79°C, 117 ml of
an aqueous solution containing 1 N NaOH was added thereto over 55 minutes and the
mixture was subjected to reaction for 240 minutes. Then, 112.5 ml of an aqueous solution
containing 19.2 g of silver nitrate was added thereto over 45 seconds and the solution
was allowed to stand for 20 minutes to lower the temperature to 30°C. The solid content
was then filtered by suction. The solid content was washed with water until the conductivity
of the filtrate reached 30 pS/cm. The thus-obtained solid content was not dried and
treated as a wet cake. Polyvinyl alcohol (trade name: PVA-205) (7.4 g) and water were
added to the wet cake of the amount corresponding to 100 g of dried solid content
to make the entire amount 385 g, and then preliminarily dispersed in a homomixer.
[0167] The preliminarily dispersed starting solution was treated three times using a disperser
(trade name: Micro-fluidizer M-110S-EH equipped with G10Z interaction chamber, manufactured
by Micro Fluidex International Corp.). Pressure of the disperser was adjusted to 1,750
kg/cm
2. Thus, silver behenate dispersion B was obtained. Silver behenate particles contained
in the thus-obtained silver behenate dispersion were acicular particles having a =
0.04 µm, b = 0.04 µm, and c = 0.8 µm, on average, and variation coefficient of 30%.
Particle size was measured by Master Sizer X (manufactured by Malvern Instruments
Ltd.). Cooling operation was performed by installing coiled heat exchangers respectively
before and after the interaction chamber and setting the desired temperature of dispersion
by adjusting the temperature of the cooling medium.
Preparation of 25 wt% Dispersion of Reducing Agent
[0168] Water (176 g) was added to 80 g of 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane
and 64 g of a 20 wt% aqueous solution of modified polyvinyl alcohol Poval MP203 (manufactured
by Kuraray Co., Ltd.), and thoroughly mixed to make a slurry. Zirconia beads (800
g) having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 5 hours, thereby the dispersion of the reducing agent was obtained.
The particles of the reducing agent contained in the thus-obtained reducing agent
dispersion had an average particle diameter of 0.72 µm.
Preparation of 10 wt% Methanol Solution of Mercapto Compound
[0169] Ten (10) grams of 3-mercapto-4-phenyl-5-heptyl-1,2,4-triazole was dissolved in 90
g of methanol.
Preparation of 20 wt% Dispersion of Mercapto Compound
[0170] Water (224 g) was added to 60 g of 3-mercapto-4-phenyl-5-heptyl-1,2,4-triazole and
32 g of a 20 wt% aqueous solution of modified polyvinyl alcohol Poval MP203 (manufactured
by Kuraray Co., Ltd.), and thoroughly mixed to make a slurry. Zirconia beads (800
g) having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 10 hours, thereby the dispersion of the mercapto compound was obtained.
The particles of the mercapto compound contained in the thus-obtained mercapto compound
dispersion had an average particle diameter of 0.67 µm.
Preparation of 30 wt% Dispersion of Organic Polyhalogen Compound
[0171] Water (224 g) was added to 44 g of tribromomethylphenylsulfone, 44 g of 3-tribromomethylsulfonyl-4-phenyl-5-tridecyl-1,2,4-triazole,
8 g of tribromomethyl-4-(2,4,6-trimethylphenylsulfonyl)phenylsulfone, 0.8 g of sodium
triisopropyl-a-naphthalenesulfonate, and 48 g of a 20 wt% aqueous solution of modified
polyvinyl alcohol Poval MP203 (manufactured by Kuraray Co., Ltd.), and thoroughly
mixed to make a slurry. Zirconia beads (800 g) having an average diameter of 0.5 mm
were added to a vessel with the above-obtained slurry and dispersed with a disperser
(1/4 G sand grinder mill, manufactured by Imex Co., Ltd.) for 5 hours, thereby a dispersion
of the organic polyhalogen compound was obtained. The particles of the organic polyhalogen
compound contained in the thus-obtained polyhalogen compound dispersion had an average
particle diameter of 0.74 µm.
Preparation of 10 wt% Methanol Solution of Phthalazine Compound
[0172] 6-Isopropylphthalazine (10 g) was dissolved in 90 g of methanol and used.
Preparation of 20 wt% Dispersion of Pigment
[0173] Water (250 g) was added to 64 g of C.I. Pigment Blue 60 and 6.4 g of Demol N (manufactured
by Kao Corporation), and thoroughly mixed to make a slurry. Zirconia beads (800 g)
having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 25 hours, thereby the dispersion of the pigment was obtained. The particles
of the pigment contained in the thus-obtained pigment dispersion had an average particle
diameter of 0.21 µm.
Preparation of 40 wt% SBR Latex
[0174] SBR Latex purified by ultrafiltration was obtained as follows.
[0175] SBR latex shown below was diluted with distilled water to 10 times, and purified
by module FS03-FC-FUY03A1 for ultrafiltration purification (Daisen Membrane System
Co., Ltd.) until the ionic conductivity became 1.5 mS/cm. The concentration of the
latex at this time was 40 wt%.
SBR Latex
[0176]
Latex of -St (68)-Bu (29)-AA (3)-
Equilibrium moisture content at 25°C 60% RH: 0.6 wt%
Average particle size: 0.1 µm
Concentration: 45 wt%
Ionic conductivity: 4.2 mS/cm
Ionic conductivity was measured using a conductometer CM-30S (manufactured by Toa
Denpa Kogyo Co., Ltd.), and starting solution of the latex (40 wt%) was measured at
25°C.
pH: 8.2
Preparation of Coating Solution for Emulsion Layer (photosensitive layer)
[0177] The above-obtained 20 wt% dispersion of pigment (1.1 g), 103 g of organic acid silver
dispersion, 5 g of the 20 wt% aqueous solution of modified polyvinyl alcohol MP-203
(manufactured by Kuraray Co., Ltd.), 25 g of the above-prepared 25 wt% reducing agent
dispersion, 11.5 g of the 30 wt% dispersion of organic polyhalogen compound, 3.1 g
of the 20 wt% dispersion of mercapto compound, 106 g of the 40 wt% SBR latex purified
by ultrafiltration, and 8 ml of the 10 wt% solution of phthalazine compound were mixed,
thereby an organic acid silver-containing solution was obtained. Silver halide grain
emulsion 1 (5 g) and silver halide emulsion 2 (5 g) had been thoroughly mixed, stirred
for 20 minutes, 10 ml of distilled water had been added thereto, and mixed with the
foregoing organic acid silver-containing solution immediately before coating, by a
static mixer to thereby prepare an emulsion layer coating solution. This coating solution
was fed to a coating die as it was in a coating silver amount of 1.4 g/m
2.
[0178] The above emulsion layer coating solution was revealed to have viscosity of 85 (mPa·s)
at 40°C (No. 1 rotor) measured by Model B viscometer (manufactured by Tokyo Keiki
Co., Ltd.).
[0179] The viscosity of the coating solution measured by RFS Fluid Spectrometer (manufactured
by Rheometrics Far East Co.) at 25°C was 1,500, 220, 70, 40, 20 (mPa·s) at shear rate
of 0.1, 1, 10, 100, 1,000 (1/sec), respectively.
Preparation of Interlayer Coating Solution of Emulsion Surface
[0180] To 772 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), an alkali
solution (a 20 wt% solution of NH
4OH as NH
4+, a 20 wt% solution of LiOH as Li
+, and a 20 wt% solution of NaOH as Na
+ were used respectively) in an addition amount shown in Tables I-1 to I-5, 0.5 g of
the 20 wt% dispersion of pigment, and 226 g of a 27.5 wt% solution of latex of methyl
methacrylate/styrene/2-ethylhexyl acrylate/ hydroxyethyl methacrylate/acrylic acid
copolymer (copolymerization weight ratio: 59/9/26/5/1) was added 2 ml of a 5 wt% aqueous
solution of Aerosol OT (manufactured by American Cyanamide Co.) to make an interlayer
coating solution, which was coated in a coating amount of 10 ml/m
2.
[0181] The viscosity of the coating solution was 21 (mPa·s) at 40°C (No. 1 rotor) measured
by Model B viscometer.
Preparation of First Protective Layer Coating Solution of Emulsion Surface
[0182] Inert gelatin (80 g) was dissolved in water, and 0.3 g of the 20 wt% dispersion of
pigment, a 10 wt% methanol solution of phthalic acid, 74 ml of a 10 wt% aqueous solution
of 4-methylphthalic acid, 28 ml of 1 N sulfuric acid, and 5 ml of a 5 wt% aqueous
solution of Aerosol OT (manufactured by American Cyanamide Co.) were added thereto.
Water was added to make the total amount 1,000 g, thereby a first protective layer
coating solution of emulsion surface was obtained, which was coated in a coating amount
of 30 ml/m
2.
[0183] The viscosity of the coating solution was 17 (mPa-s) at 40°C (No. 1 rotor) measured
by Model B viscometer. A coating solution in which polyvinyl alcohol was used in place
of gelatin was prepared.
Preparation of Second Protective Layer Coating Solution of Emulsion Surface
[0184] Inert gelatin (100 g) was dissolved in water, and 0.2 g of the 20 wt% dispersion
of pigment, 20 ml of a 5 wt% solution of potassium N-perfluorooctylsulfonyl-N-propylalanine,
16 ml of a 5 wt% solution of Aerosol OT (manufactured by American Cyanamide Co.),
25 g of polymethyl methacrylate fine particles (average particle size: 4.0 µm), 1.4
g of phthalic acid, 1.6 g of 4-methylphthalic acid, 44 ml of 1 N sulfuric acid, and
445 ml of a 4 wt% chrome alum were added thereto. Water was added to make the total
amount 2,000 g, thereby a second protective layer coating solution was obtained, which
was coated in coating amount of 20 ml/m
2.
[0185] The viscosity of the coating solution was 9 (mPa·s) at 40°C (No. 1 rotor) measured
by Model B viscometer. A coating solution in which polyvinyl alcohol was used in place
of gelatin and boric acid was used in place of chrome alum was prepared.
Preparation of PET Support
[0186] PET having an intrinsic viscosity IV = 0.66 (measured in phenol/tetrachloroethane
(6/4 by weight) at 25°C) was obtained according to ordinary method using terephthalic
acid and ethylene glycol. After the obtained PET was pelletized and dried at 130°C
for 4 hours, melted at 300°C, extruded from T-die, and suddenly cooled, thereby an
unstretched film having a film thickness after thermal fixation of 175 µm was obtained.
[0187] The film was stretched to 3.3 times in the machine direction with rollers having
different peripheral speeds, then 4.5 times in the transverse direction by means of
a tenter. The temperatures at that time were 110°C and 130°C respectively. Subsequently,
the film was subjected to thermal fixation at 240°C for 20 seconds, then relaxation
by 4% in the transverse direction at the same temperature. The chuck part of the tenter
was then slit, and both edges of the film were knurled. The film was rolled at 4 kg/cm
2, thereby a roll of film having a thickness of 175 µm was obtained.
Corona Discharge Treatment of Support Surface
[0188] Both surfaces of the support were put under room temperature and corona discharge
treatment was performed at 20 m/min with a solid state corona treating apparatus model
6KVA manufactured by Piller Co. From the reading of electric current/voltage, treatment
applied to the support at that time was revealed to be 0.375 kV·A·min/m
2. The frequency at treatment at that time was 9.6 kHz and the gap clearance between
the electrode and the dielectric roll was 1.6 mm.
Preparation of Undercoated Support
(1) Undercoating
(1-1) Undercoating Tayer Coating
[0189]
Prescription (1) (first layer) |
Butadiene/styrene copolymer latex (solid content: 43 wt%, weight ratio of butadiene/styrene:
32/68) |
13 ml |
8 wt% aqueous solution of sodium 2,4-dichloro-6-hydroxy-s-triazine |
7 ml |
1 wt% aqueous solution of sodium lauryl-benzenesulfonate |
1.6 ml |
Distilled water |
80 ml |
Prescription (2) (second layer on the photosensitive layer side) |
Gelatin |
0.9 g |
20 wt% dispersion of pigment |
1 g |
Methyl cellulose (Metolose SM15, substitution degree: 1.79 to 1.83) |
0.1 g |
Acetic acid (concentration: 99 wt%) |
0.02 ml |
Distilled water |
98 ml |
Prescription (3) (second layer on the back surface side) |
SnO2/Sb (9/1 by weight, average particle size: 0.25 µm) |
100 mg/m2 |
Gelatin |
77 mg/m2 |
Sodium dodecylbenzenesulfonate |
1 mg/m2 |
Sodium dihexyl-α-sulfosuccinato |
4 mg/m2 |
Preparation of Undercoated Support
[0190] Both surfaces of the above-prepared biaxially stretched polyethylene terephthalate
support having a film thickness of 175 µm were subjected to corona discharge treatment,
then the above undercoating solution prescription (1) was coated by means of a wire
bar in a wet coating amount of 6 ml/m
2 (per one surface side) and dried at 180°C for 5 minutes. Subsequently, one surface
(photosensitive layer side) was subjected to corona discharge treatment, then the
above undercoating solution prescription (2) was coated by means of a wire bar in
a wet coating amount of 9 ml/m
2 and dried at 180°C for 5 minutes. The back surface was coated with undercoating solution
prescription (3) by means of a wire bar in a wet coating amount of 5 ml/m
2 and dried at 180°C for 6 minutes. Thus, the undercoated support was prepared.
Preparation of Back Coating Solution
Preparation of Solid Fine Particle Dispersion Solution (a) of Base Precursor
[0191] A base precursor compound 11 shown below (64 g), 28 g of a diphenylsulfone compound
12 shown below, and 10 g of surfactant Demole N (manufactured by Kao Corporation)
were mixed with 220 ml of distilled water. The mixed solution was dispersed using
beads in a sand mill (1/4 Gallon sand grinder mill, manufactured by Imex Co., Ltd.),
thereby a solid fine particle co-dispersion solution (a) of the base precursor compound
and the diphenylsulfone compound having an average particle size of 0.2 µm was obtained.
Preparation of Solid Fine Particle Dispersion Solution of Dye
[0192] Cyanine dye compound 13 shown below (9.6 g) and 5.8 g of sodium p-alkylbenzenesulfonate
were mixed with 305 ml of distilled water. The mixed solution was dispersed using
beads in a sand mill (1/4 Gallon sand grinder mill, manufactured by Imex Co., Ltd.),
thereby a solid fine particle dispersion solution of the dye having an average particle
size of 0.2 µm was obtained.
Preparation of Antihalation Layer Coating Solution
[0193] PVA-217 (17 g), 9.6 g of polyacrylamide, 70 g of the above solid fine particle dispersion
solution (a) of the base precursor, 56 g of the above solid fine particle dispersion
solution of the dye, 1.5 g of polymethyl methacrylate fine particles (average particle
size: 6.5 µm), 2.2 g of sodium polyethylenesulfonate, 0.2 g of a coloring dye compound
14, and 844 ml of H
2O were mixed. Thus, an antihalation layer coating solution was prepared.
Preparation of Back Surface Protective Layer Coating Solution
[0194] To a reaction vessel maintained at 40°C were added and mixed 50 g of PVA-117, 0.2
g of sodium polystyrenesulfonate, 2.4 g of N,N'-ethylenebis(vinyl sulfone acetamide),
1 g of sodium t-octylphenoxyethoxyethanesulfonate, 30 mg of compound 15, 32 mg of
C
8F
17SO
3K, 64 mg of C
8F
17SO
2N(C
3H
7)(CH
2CH
2O)
4(CH
2)
4-SO
3Na, 8.8 g of acrylic acid/ethyl acrylate copolymer (copolymerization weight ratio:
5/95), and 950 ml of H
2O to prepare a back surface protective layer coating solution.
Preparation of Photothermographic Photosensitive Material
[0195] On the back side surface of the above-undercoated polyethylene terephthalate support,
antihalation layer coating solution and the back surface protective layer coating
solution were simultaneously coated and dried in such a manner that the coating amount
of the solid content of the solid fine particle dye of antihalation layer coating
solution became 0.04 g/m
2 and the PVA coating amount of the back surface protective layer coating solution
became 1 g/m
2, thereby an antihalation backing layer was prepared.
[0196] The emulsion layer, the interlayer, the first protective layer and the second protective
layer were simultaneously multilayer-coated by slide bead coating method on the opposite
side of the backing layer side in this order from the undercoating side, thereby photothermographic
(photosensitive) material Sample was prepared.
[0197] Coating speed was 160 m/min. The distance between the tip of the coating die and
the support was 0.18 mm. The pressure in the low pressure chamber was set lower than
atmospheric pressure by 392 Pa. In the subsequent chilling zone, air of dry-bulb temperature
of 18°C and wet-bulb temperature of 12°C was blown for 30 seconds. After the coating
solution was dried, dry air of dry-bulb temperature of 30°C and wet-bulb temperature
of 18°C was blown at helical floating type drying zone for 200 seconds. The sample
was then passed through drying zone at 70°C for 30 seconds, and then cooled to 25°C,
thereby the solvent in the coating solution was evaporated. In the chilling zone and
drying zone, the average wind speed was 7 m/sec.
Evaluation of Silver Tone Due to Variation of Heat Development Condition
[0198] The sample of photothermographic (photosensitive) material prepared was subjected
to stepwise gradation exposure with laser beams vertically multiplied by applying
high frequency convolution using a semiconductor laser emitting at 660 nm. Then, heat
development was performed for 20 seconds at temperatures of 117°C, 120°C and 123°C
with heat developing device 10 of a plate heater type described in Fig. 1 in JP-A-11-133572,
and the difference of silver tone due to variation of heat development condition was
evaluated visually according to the following criteria. The sample was deodorized
with metal mesh and an active carbon filter.
L: Difference of silver tone due to temperature condition is large and impracticable.
M: Difference of silver tone due to temperature condition is observed but in allowable
range.
S: Difference of silver tone due to temperature condition is not observed and good.
[0199] The silver tone obtained by heat development at 120°C for 20 seconds was visually
evaluated.
: Pure blackish silver tone, favorable.
o: Deviated a little from pure black but is good.
Δ: A trace of a tincture of magenta, or a tincture of cyan, or a tincture of yellow
is observed, allowable.
Δx: A tincture of magenta, or a tincture of cyan, or a tincture of yellow is considerably
observed, but is allowable.
x: A tincture of magenta, or a tincture of cyan, or a tincture of yellow is strong,
impracticable.
Evaluation of Storage Stability
[0200] Difference in Dmin between the sample of the prepared photothermographic (photosensitive)
material which was allowed to stand at 35°C 70% RH for 7 days as a coated bulk product
and a sample which was refrigerated for 7 days as a coated bulk product was measured.
Each sample was subjected to stepwise gradation exposure with a semiconductor laser
emitting at 660 nm not applying high frequency convolution. Then, heat development
was performed for 20 seconds at 120°C with the same heat developing device 10. Difference
in Dmin was expressed as the difference in measured V value of Macbeth densitometer.
[0201] The results obtained are shown in Tables I-1 to I-5. In Tables I-1, I-4 and I-5,
samples in which gelatin is used as the main binder in the first and second layers
are shown, and in Tables I-2 and I-3, samples in which PVA is used as the main binder
in the first and second layers are shown.
TABLE I-1
Series using gelatin in the first and second protective layers |
Sample No. |
Shape of Organic Acid Silver |
Alkali Ion (mmol/m2) |
Storage Stability of Coated Bulk Product |
Silver Tone Difference |
1 (Comparison) |
Acicular |
- |
0.47 |
L |
2 (Comparison) |
Acicular |
NH4+ (0.28) |
0.41 |
L |
3 (Comparison) |
Acicular |
NH4+ (1.11) |
0.38 |
L |
4 (Comparison) |
Acicular |
NH4+ (2.11) |
0.42 |
L |
5 (Comparison) |
Acicular |
NH4+ (3.89) |
0.51 |
L |
6 (Comparison) |
Scaly |
- |
0.14 |
L |
7 (Invention) |
Scaly |
NH4+ (0.28) |
0.08 |
M |
8 (Invention) |
Scaly |
NH4+ (1.11) |
0.07 |
S |
9 (Invention) |
Scaly |
NH4+ (2.11) |
0.08 |
S |
10 (Comparison) |
Scaly |
NH4+ (3.89) |
0.18 |
S |
TABLE I-2
Series using PVA in the first and second protective layers |
Sample No. |
Shape of Organic Acid Silver |
Alkali Ion (mmol/m2) |
Storage Stability of Coated Bulk Product |
Silver Tone Difference |
11 (Comparison) |
Acicular |
- |
0.46 |
L |
12 (Comparison) |
Acicular |
NH4+ (0.28) |
0.39 |
L |
13 (Comparison) |
Acicular |
NH4+ (1.11) |
0.38 |
L |
14 (Comparison) |
Acicular |
NH4+ (2.11) |
0.41 |
L |
15 (Comparison) |
Acicular |
NH4+ (3.89) |
0.50 |
L |
16 (Comparison) |
Scaly |
- |
0.13 |
L |
17 (Invention) |
Scaly |
NH4+ (0.28) |
0.08 |
M |
18 (Invention) |
Scaly |
NH4+ (1.11) |
0.07 |
S |
19 (Invention) |
Scaly |
NH4+ (2.11) |
0.07 |
S |
20 (Comparison) |
Scaly |
NH4+ (3.89) |
0.17 |
S |
TABLE I-3
Series using PVA in the first and second protective layers |
Sample No. |
Shape of Organic Acid Silver |
Alkali Ion (mmol/m2) |
Storage Stability of Coated Bulk Product |
Silver Tone Difference |
31 (Comparison) |
Acicular |
- |
0.47 |
L |
32 (Comparison) |
Acicular |
Li+ (0.14) |
0.42 |
L |
33 (Comparison) |
Acicular |
Li+ (0.72) |
0.39 |
L |
34 (Comparison) |
Acicular |
Li+ (2.16) |
0.44 |
L |
35 (Comparison) |
Acicular |
Li+ (4.32) |
0.54 |
L |
36 (Comparison) |
Scaly |
- |
0.14 |
L |
37 (Invention) |
Scaly |
Li+ (0.14) |
0.10 |
M |
38 (Invention) |
Scaly |
Li+ (0.72) |
0.09 |
S |
39 (Invention) |
Scaly |
Li+ (2.16) |
0.08 |
S |
40 (Comparison) |
Scaly |
Li+ (4.32) |
0.20 |
S |
TABLE I-4
Series using gelatin in the first and second protective layers |
Sample No. |
Shape of Organic Acid Silver |
Alkali Ion (mmol/m2) |
Storage Stability of Coated Bulk Product |
Silver Tone Difference |
41 (Comparison) |
Acicular |
- |
0.47 |
L |
42 (Comparison) |
Acicular |
Na+ (0.12) |
0.45 |
L |
43 (Comparison) |
Acicular |
Na+ (0.82) |
0.32 |
L |
44 (Comparison) |
Acicular |
Na+ (1.64) |
0.42 |
L |
45 (Comparison) |
Acicular |
Na+ (5.22) |
0.52 |
L |
46 (Comparison) |
Scaly |
- |
0.14 |
L |
47 (Invention) |
Scaly |
Na+ (0.12) |
0.08 |
M |
48 (Invention) |
Scaly |
Na+ (0.82) |
0.05 |
S |
49 (Invention) |
Scaly |
Na+ (1.64) |
0.09 |
S |
50 (Comparison) |
Scaly |
Na+ (5.22) |
0.18 |
S |
[0202] From the results in Tables I-1, I-2, I-3, I-4 and I-5, the effect of the present
invention is apparent. Samples according to the present invention are excellent in
photographic properties.
EXAMPLE I-2
[0203] Samples were prepared in the same manner as in Example I-1 except that SBR latex
used in emulsion layers was not purified. The same results as in Example I-1 were
obtained.
EXAMPLE I-3
[0204] Samples were prepared in the same manner as in Example I-1 except that latexes Lb1
and Lc1 (equilibrium moisture content at 25°C 60% RH was less than 2 wt% with both
Lb1 and Lc1) shown below were used in place of SBR latex used in emulsion layers.
[0205] The same results as in Example I-1 were obtained.
Synthesis of Lb1
[0206] Into a glass autoclave (TEM-V1000, manufactured by Taiatsu Glass Kogyo Co., Ltd.)
were put 140 g of styrene, 280 g of distilled water, 4.44 g of a surfactant (Sandet
BL, manufactured by Sanyo Kasei Co., Ltd.), and 6 g of acrylic acid, and the content
was stirred for 1 hour in a nitrogen atmosphere. Thereafter, 54 g of 2-ethylhexyl
acrylate was added to the reaction mixture and the temperature was raised to 70°C.
Then, 20 g of a 5 wt% aqueous ammonium persulfate solution was added thereto and stirring
was continued for 10 hours. After stirring was finished, the temperature of the reaction
vessel was lowered to room temperature, thereby a styrene-acryl latex was obtained.
1 N aqueous ammonia was added to this latex to adjust pH to 7.5.
[0207] Thus, latex Lb1 having an average particle diameter of 98 nm and concentration of
42 wt% was obtained. Equilibrium moisture content of the polymer at 25°C 60% RH was
0.7 wt%.
Synthesis of Lc1
[0208] Into a glass autoclave (TEM-V1000, manufactured by Taiatsu Glass Kogyo Co., Ltd.)
were put 126 g of methyl methacrylate, 280 g of distilled water, 8.2 g of a surfactant
(Sandet BL, manufactured by Sanyo Kasei Co., Ltd.), and 4 g of acrylic acid, and the
content was stirred for 1 hour in a nitrogen atmosphere. Thereafter, 70 g of ethyl
acrylate was added to the reaction mixture and the temperature was raised to 60°C.
Then, 20 g of a 5 wt% aqueous potassium persulfate solution was added thereto and
stirring was continued for 10 hours. After stirring was finished, the temperature
of the reaction vessel was lowered to room temperature, thereby an acryl latex was
obtained. 1 N aqueous ammonia was added to this latex to adjust pH to 7.5.
[0209] Thus, latex Lc1 having an average particle diameter of 101 nm and concentration of
44 wt% was obtained. Equilibrium moisture content of the polymer at 25°C 60% RH was
0.7 wt%.
EXAMPLE I-4
[0210] Samples were prepared in the same manner as in Examples I-1 to I-3 except that photosensitive
silver halide was excluded. The obtained samples were heated to 100°C or more with
a thermosensitive type thermal head (maximum temperature: 230°C). The same results
as in Examples I-1 to I-3 were obtained.
EXAMPLE II-1
Preparation of Silver Halide Grains 1
[0211] To 1,421 ml of distilled water were added 6.7 ml of a 1 wt% potassium bromide solution,
8.2 ml of 1 N nitric acid and 21.8 g of phthalated gelatin. This mixed solution was
stirred in a titanium-coated stainless reaction vessel with maintaining the temperature
at 25°C. Solution al (37.04 g of silver nitrate was diluted with distilled water to
make 159 ml) and solution b1 (32.6 g of potassium bromide was diluted with distilled
water to make 200 ml) were prepared. The entire amount of solution al was added to
the reaction vessel at a constant flow rate by a controlled double jet method with
maintaining pAg at 8.1 over 1 minute (solution b1 was added by a controlled double
jet method) . Then, 30 ml of a 3.5 wt% hydrogen peroxide aqueous solution was added,
further, 33.6 ml of a 3 wt% aqueous solution of benzimidazole was added thereto. Solution
a2 (solution a1 was again diluted with distilled water to make 317.5 ml) and solution
b2 (dipotassium hexachloroiridate was dissolved in solution b1 so as to make the concentration
1 × 10
-4 mol per mol of the silver, diluted with distilled water to reach the final volume
of 2 times of solution b1, i.e., 400 ml) were prepared. The entire amount of solution
a2 was added to the reaction vessel at a constant flow rate by a controlled double
jet method with maintaining pAg at 8.1 over 10 minutes (solution b2 was added by a
controlled double jet method). Then, 50 ml of a 0.5 wt% methanol solution of 2-mercapto-5-methylbenzimidazole
was added, further, pAg was lowered to 7.5 with silver nitrate, pH was adjusted with
1 N sulfuric acid to 3.8, and stirring was stopped. The reaction solution was subjected
to precipitation, desalting and washing processes, 3.5 g of deionized gelatin was
added, and then 1 N sodium hydroxide was added to adjust pH to 6.0 and pAg to 8.2,
thereby a silver halide dispersion was obtained.
[0212] The grains in the thus-prepared silver halide emulsion were pure silver bromide grains
having an average equivalent-sphere diameter of 0.031 µm and equivalent-sphere diameter
variation coefficient of 11%. Grain size was the average of 1, 000 grains obtained
by electron microscope. {100} face ratio of this grain was 85% according to the Kubelka-Munk
method.
[0213] The temperature of the above emulsion was raised to 45°C with stirring, then 5 ml
of a 0.5 wt% methanol solution of N,N'-dihydroxy-N",N"-diethylmelamine and 5 ml of
a 3.5 wt% methanol solution of phenoxyethanol were added thereto, and 1 minute after,
3×10
-5 mol per mol of the silver of sodium benzenethiosulfonate was added. Further 2 minutes
after, a solid dispersion of spectral sensitizing dye 1 (an aqueous gelatin solution)
was added in an amount of 5×10
-3 mol per mol of the silver, and further 2 minutes after, 5×10
-5 mol per mol of the silver of a tellurium compound was added and the reaction solution
was subjected to ripening for 50 minutes. Immediately before completion of ripening,
2-mercapto-5-methylbenzimidazole in an amount of 1×10
-3 mol, and mercapto compound 1 in an amount of 1.1×10
-3 mol, each per mol of the silver, were added to the reaction solution. The temperature
was lowered to 32°C. Thus, silver halide grains 1 were prepared.
Preparation of Silver Halide Grains 2
[0214] Phthalated gelatin (22 g) and 30 mg of potassium bromide were dissolved in 700 ml
of water, pH was adjusted to 5.0 at 350C. An aqueous solution (159 ml) containing
18.6 g of silver nitrate and 0.9 g of ammonium nitrate and an aqueous solution containing
potassium bromide and potassium iodide in molar ratio of 92/8 were added to the foregoing
solution by a controlled double jet method over 10 minutes with maintaining pAg at
7.7. Subsequently, 476 ml of an aqueous solution containing 55.4 g of silver nitrate
and 2 g of ammonium nitrate and an aqueous solution containing 1×10
-5 mol/liter of dipotassium hexachloroiridate and 1 mo/liter of potassium bromide were
added to the foregoing solution by a controlled double jet method over 30 minutes
with maintaining pAg at 7.7. Subsequently, 1 g of 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene
was added thereto, pH was lowered and the reaction solution was subjected to coagulation
precipitation, and desalted. Then, 0.1 g of phenoxyethanol was added to adjust pH
to 5.9 and pAg to 8.2, thereby the formation of silver iodobromide grains was terminated.
The thus-obtained silver halide grains were cubic grains having an iodine content
at core part: 8 mol%, average: 2 mol%, an average grain size of 0.005 µm, a variation
coefficient of the projected area diameter of 8%, and {100} face ratio of 88%.
[0215] The temperature of the thus-obtained silver halide grains was raised to 60°C. Sodium
thiosulfate (85 µmol), 1.1×10
-5 mol of 2,3,4,5,6-pentafluorophenyldiphenylphosphineselenide, 1.5×10
-5 mol of a tellurium compound, 3.5×10
-8 mol of chloroauric acid, and 2.7×10
-4 mol of thiocyanic acid, each per mol of the silver, were added to the above silver
halide grains and ripened for 120 minutes, then quenched to 40°C. Spectral sensitizing
dye 1 in an amount of 1×10
-4 mol and 2-mercapto-5-methylbenzimidazole in an amount of 5×10
-4 mol were added thereto, and then the solution was quenched to 30°C, thereby silver
halide emulsion 2 was obtained.
Preparation of Scaly Fatty Acid Silver Salt
[0216] Behenic acid (87.6 g) (manufactured by Henkel Co., trade name: Edenor C22-85R), 423
ml of distilled water, 49.2 ml of an aqueous solution containing 5 N NaOH, and 120
ml of tert-butanol were mixed, and the mixture was subjected to reaction for 1 hour
at 75°C, thereby a sodium behenate solution was obtained. Apart from the sodium behenate
solution, 206.2 ml of an aqueous solution containing 40.4 g of silver nitrate (pH
4.0) was prepared and maintained at 10°C. A reaction vessel containing 635 ml of distilled
water and 30 ml of tert-butanol was maintained at 30°C, with stirring the content
in the reaction vessel, the entire amount of the above sodium behenate solution and
the entire amount of the aqueous silver nitrate solution were added to the reaction
vessel at a constant flow rate over 62 minutes and 10 seconds and 60 minutes, respectively,
in such a manner that only the aqueous silver nitrate solution was added from the
start of the addition, 7 minutes and 20 seconds after the start of the addition of
the aqueous silver nitrate solution, the addition of the sodium behenate solution
was started, and only the sodium behenate solution was added for 9 minutes and 30
seconds after the termination of the addition of the aqueous silver nitrate solution.
The temperature in the reaction vessel was maintained at 30°C and the outer temperature
was controlled so as not to increase the temperature. The piping of the addition system
of the sodium behenate solution was warmed by a steamed jacket method, and steam aperture
was adjusted so that the solution temperature at the outlet of the addition nozzle
tip became 75°C. The piping of the addition system of the aqueous silver nitrate solution
was warmed by circulating chilled water in the outer pipe of the double pipe. The
positions where the sodium behenate solution and the aqueous silver nitrate solution
were added were arranged symmetrically with the stirring axle between, and the height
of the position was adjusted so as not to touch the reaction solution.
[0217] After the addition of the sodium behenate solution was finished, the reaction solution
was stirred at the same temperature for 20 minutes and allowed to stand to lower the
temperature to 25°C. The solid content was then filtered by suction. The solid content
was washed with water until the conductivity of the filtrate reached 30 µS/cm. Thus,
a fatty acid silver salt was obtained. The solid content obtained was not dried and
stored as a wet cake.
[0218] The shape of the obtained silver behenate particles was evaluated with an electron
microscope. The obtained silver behenate particles were scaly crystals having a =
0.14 µm, b = 0.4 µm, and c = 0.6 µm, on average, and variation coefficient of the
average equivalent-sphere diameter of 15%.
[0219] Polyvinyl alcohol (trade name: PVA-217) (7.4 g) and water were added to the wet cake
of the amount corresponding to 100 g of dried solid content to make the entire amount
385 g, and then preliminarily dispersed in a homomixer.
[0220] The preliminarily dispersed starting solution was treated three times using a disperser
(trade name: Micro-fluidizer M-110S-EH equipped with G10Z interaction chamber, manufactured
by Micro Fluidex International Corp.). Pressure of the disperser was adjusted to 1,750
kg/cm
2. Thus, silver behenate dispersion was obtained. Cooling. operation was performed
by installing coiled heat exchangers respectively before and after the interaction
chamber and setting the desired temperature of dispersion by adjusting the temperature
of the cooling medium.
Preparation of Acicular Fatty Acid Silver Salt (comparison)
[0221] While stirring 43.8 g of behenic acid (manufactured by Henkel Co., trade name: Edenor
C22-85R), 730 ml of distilled water, and 60 ml of tert-butanol at 79°C, 117 ml of
an aqueous solution containing 1 N NaOH was added thereto over 55 minutes and the
mixture was allowed to reaction for 240 minutes. Then, 112.5 ml of an aqueous solution
containing 19.2 g of silver nitrate was added thereto over 45 seconds and the solution
was allowed to stand for 20 minutes to lower the temperature to 30°C. The solid content
was then filtered by suction. The solid content was washed with water until the conductivity
of the filtrate reached 30 µS/cm. The thus-obtained solid content was not dried and
treated as a wet cake. Polyvinyl alcohol (trade name: PVA-205) (7.4 g) and water were
added to the wet cake of the amount corresponding to 100 g of dried solid content
to make the entire amount 385 g, and then preliminarily dispersed in a homomixer.
[0222] The preliminarily dispersed starting solution was treated three times using a disperser
(trade name: Micro-fluidizer M-110S-EH equipped with G10Z interaction chamber, manufactured
by Micro Fluidex International Corp.). Pressure of the disperser was adjusted to 1,750
kg/cm
2. Thus, silver behenate dispersion B was obtained. Silver behenate particles contained
in the thus-obtained silver behenate dispersion were acicular particles having a =
0.04 µm, b = 0.04 µm, and c = 0.8 µm, on average, and variation coefficient of 30%.
Particle size was measured by Master Sizer X (manufactured by Malvern Instruments
Ltd.). Cooling operation was performed by installing coiled heat exchangers respectively
before and after the interaction chamber and setting the desired temperature of dispersion
by adjusting the temperature of the cooling medium.
Preparation of 25 wt% Dispersion of Reducing Agent
[0223] Water (176 g) was added to 80 g of 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5,5-trimethylhexane
and 64 g of a 20 wt% aqueous solution of modified polyvinyl alcohol Poval MP203 (manufactured
by Kuraray Co., Ltd.), and thoroughly mixed to make a slurry. Zirconia beads (800
g) having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 5 hours, thereby the dispersion of the reducing agent was obtained.
The particles of the reducing agent contained in the thus-obtained reducing agent
dispersion had an average particle diameter of 0.72 µm.
Preparation of 10 wt% Methanol Solution of Mercapto Compound
[0224] Ten (10) grams of 3-mercapto-4-phenyl-5-heptyl-1,2,4-triazole was dissolved in 90
g of methanol.
Preparation of 20 wt% Dispersion of Mercapto Compound
[0225] Water (224 g) was added to 64 g of 3-mercapto-4-phenyl-5-heptyl-1,2,4-triazole and
32 g of a 20 wt% aqueous solution of modified polyvinyl alcohol Poval MP203 (manufactured
by Kuraray Co., Ltd.), and thoroughly mixed to make a slurry. Zirconia beads (800
g) having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 10 hours, thereby the dispersion of the mercapto compound was obtained.
The particles of the mercapto compound contained in the thus-obtained mercapto compound
dispersion had an average particle diameter of 0.67 µm.
Preparation of 30 wt% Dispersion of Organic Polyhalogen Compound
[0226] Water (224 g) was added to 44 g of tribromomethylphenylsulfone, 44 g tribromomethylsulfonyl-4-phenyl-5-tridecyl-1,2,4-triazole,
8 g of tribromomethyl-4-(2,4,6-trimethylphenylsulfonyl)phenylsulfone, 0.8 g of sodium
triisopropyl-α-naphthalenesulfonate, and 48 g of a 20 wt% aqueous solution of modified
polyvinyl alcohol Poval MP203 (manufactured by Kuraray Co., Ltd.), and thoroughly
mixed to make a slurry. Zirconia beads (800 g) having an average diameter of 0.5 mm
were added to a vessel with the above-obtained slurry and dispersed with a disperser
(1/4 G sand grinder mill, manufactured by Imex Co., Ltd.) for 5 hours, thereby a dispersion
of the organic polyhalogen compound was obtained. The particles of the organic polyhalogen
compound contained in the thus-obtained polyhalogen compound dispersion had an average
particle diameter of 0.74 µm.
Preparation of 10 wt% Methanol Solution of Phthalazine Compound
[0227] 6-Isopropylphthalazine (10 g) was dissolved in 90 g of methanol and used.
Preparation of 20 wt% Dispersion of Pigment
[0228] Water (250 g) was added to 64 g of C.I. Pigment Blue 60 and 6.4 g of Demole N (manufactured
by Kao Corporation), and thoroughly mixed to make a slurry. Zirconia beads (800 g)
having an average diameter of 0.5 mm were added to a vessel with the above-obtained
slurry and dispersed with a disperser (1/4 G sand grinder mill, manufactured by Imex
Co., Ltd.) for 25 hours, thereby the dispersion of the pigment was obtained. The particles
of the pigment contained in the thus-obtained pigment dispersion had an average particle
diameter of 0.21 µm.
Preparation of 40 wt% SBR Latex
[0229] SBR Latex purified by ultrafiltration was obtained as follows.
[0230] SBR latex shown below was diluted with distilled water to 10 times, and purified
by module FS03-FC-FUY03A1 for ultrafiltration purification (Daisen Membrane System
Co., Ltd.) until the ionic conductivity became 1.5 mS/cm. The concentration of the
latex at this time was 40 wt%.
SBR Latex
[0231]
Latex of -St (68)-Bu (29)-AA (3)-
Equilibrium moisture content at 25°C 60% RH: 0.6 wt%
Average particle size: 0.1 µm
Concentration: 45 wt%
Ionic conductivity: 4.2 mS/cm
Ionic conductivity was measured using a conductometer CM-30S (manufactured by Toa
Denpa Kogyo Co., Ltd.), and starting solution of the latex (40 wt%) was measured at
25°C.
pH: 8.2
Preparation of Coating Solution for Emulsion Layer (photosensitive layer)
[0232] The above-obtained 20 wt% dispersion of pigment (1.1 g), 103 g of organic acid silver
dispersion, 5 g of the 20 wt% aqueous solution of modified polyvinyl alcohol MP-203
(manufactured by Kuraray Co., Ltd.), 25 g of the above-prepared 25 wt% reducing agent
dispersion, 11.5 g of the 30 wt% dispersion of organic polyhalogen compound, 3.1 g
of the 20 wt% dispersion of mercapto compound, 106 g of the 40 wt% SBR latex purified
by ultrafiltration, and 8 ml of the 10 wt% solution of phthalazine compound were mixed,
thereby an organic acid silver-containing solution was obtained. Silver halide grain
emulsion 1 (5 g) and silver halide emulsion 2 (5 g) had been thoroughly mixed, stirred
for 20 minutes, 10 ml of distilled water had been added thereto, and mixed with the
foregoing organic acid silver-containing solution immediately before coating with
a stack mixer to thereby prepare an emulsion layer coating solution. This coating
solution was fed to a coating die as it was in a coating silver amount of 1.4 g/m
2.
[0233] The above emulsion layer coating solution was revealed to have viscosity of 85 (mPa·s)
at 40°C (No. 1 rotor) measured by Model B viscometer (manufactured by Tokyo Keiki
Co., Ltd.).
[0234] The viscosity of the coating solution measured by RFS Fluid Spectrometer (manufactured
by Rheometrics Far East Co.) at 25°C was 1,500, 220, 70, 40, 20 (mPa·s) at shear rate
of 0.1, 1, 10, 100, 1,000 (1/sec), respectively.
Preparation of Interlayer Coating Solution of Emulsion Surface
[0235] To 772 g of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 0.5 g
of the 20 wt% dispersion of pigment, and 226 g of a 27.5 wt% solution of latex of
methyl methacrylate/styrene/2-ethylhexyl acrylate/hydroxyethyl methacrylate/acrylic
acid copolymer (copolymerization weight ratio: 59/9/26/5/1) was added 2 ml of a 5
wt% aqueous solution of Aerosol OT (manufactured by American Cyanamide Co.) to make
an interlayer coating solution, which was coated in a coating amount of 10 ml/m
2.
[0236] The viscosity of the coating solution was 21 (mPa-s) at 40°C (No. 1 rotor) measured
by Model B viscometer.
Preparation of First Protective Layer Coating Solution of Emulsion Surface
[0237] Inert gelatin (80 g) was dissolved in water, and 6 g of a toning agent (shown in
Tables II-1 and II-2), 0.3 g of the 20 wt% dispersion of pigment, 28 ml of 1 N sulfuric
acid, and 5 ml of a 5 wt% aqueous solution of Aerosol OT (manufactured by American
Cyanamide Co.) were added thereto. Water was added to make the total amount 1,000
g, thereby a first protective layer coating solution of emulsion surface was obtained,
which was coated in a coating amount of 30 ml/m
2.
[0238] The viscosity of the coating solution was 17 (mPa·s) at 40°C (No. 1 rotor) measured
by Model B viscometer. A coating solution in which polyvinyl alcohol was used in place
of gelatin was prepared.
Preparation of Second Protective Layer Coating Solution of Emulsion Surface
[0239] Inert gelatin (100 g) was dissolved in water, and 0.2 g of the 20 wt% dispersion
of pigment, 20 ml of a 5 wt% solution of potassium N-perfluorooctylsulfonyl-N-propylalanine,
16 ml of a 5 wt% solution of Aerosol OT (manufactured by American Cyanamide Co.),
25 g of polymethyl methacrylate fine particles (average particle size: 4.0 µm), 44
ml of 1 N sulfuric acid, and 445 ml of a 4 wt% chrome alum were added thereto. Water
was added to make the total amount 2,000 g, thereby a second protective layer coating
solution was obtained, which was coated in coating amount of 20 ml/m
2.
[0240] The viscosity of the coating solution was 9 (mPa-s) at 40°C (No. 1 rotor) measured
by Model B viscometer. A coating solution in which polyvinyl alcohol was used in place
of gelatin and boric acid was used in place of chrome alum was prepared.
Preparation of PET Support
[0241] PET having an intrinsic viscosity IV = 0.66 (measured in phenol/tetrachloroethane
(6/4 by weight) at 25°C) was obtained according to ordinary method using terephthalic
acid and ethylene glycol. After the obtained PET was pelletized and dried at 130°C
for 4 hours, melted at 300°C, extruded from T-die, and suddenly cooled, thereby an
unstretched film having a film thickness after thermal fixation of 175 µm was obtained.
[0242] The film was stretched to 3.3 times in the machine direction with rollers having
different peripheral speeds, then 4.5 times in the transverse direction by means of
a tenter. The temperatures at that time were 110°C and 130°C respectively. Subsequently,
the film was subjected to thermal fixation at 240°C for 20 seconds, then relaxation
by 4% in the transverse direction at the same temperature. The chuck part of the tenter
was then slit, and both edges of the film were knurled. The film was rolled at 4 kg/cm
2, thereby a roll of film having a thickness of 175 µm was obtained.
Corona Discharge Treatment of Support Surface
[0243] Both surfaces of the support were put under room temperature and corona discharge
treatment was performed at 20 m/min with a solid state corona treating apparatus model
6KVA manufactured by Piller Co. From the reading of electric current/voltage, treatment
applied to the support at that time was revealed to be 0.375 kV·A·min/m
2. The frequency at treatment at that time was 9.6 kHz and the gap clearance between
the electrode and the dielectric roll was 1.6 mm.
Preparation of Undercoated Support
(1) Undercoating
(1-1) Undercoating Tayer Coating
[0244]
Prescription (1) (first layer) |
|
Butadiene/styrene copolymer latex (solid content: 43 wt%, weight ratio of butadiene/styrene:
32/68) |
13 ml |
8 wt% aqueous solution of sodium 2,4-dichloro-6-hydroxy-s-triazine |
7 ml |
1 wt% aqueous solution of sodium lauryl-benzenesulfonate |
1.6 ml |
Distilled water |
80 ml |
Prescription (2) (second layer on the photosensitive layer side) |
Gelatin |
0.9 g |
20 wt% dispersion of pigment |
1 g |
Methyl cellulose (Metolose SM15, substitution degree: 1.79 to 1.83) |
0.1 g |
Acetic acid (concentration: 99 wt%) |
0.02 ml |
Distilled water |
98 ml |
Prescription (3) (second layer on the back surface side) |
SnO2/Sb (9/1 by weight, average particle |
100 mg/m2 |
size: 0.25 µm) |
|
Gelatin |
77 mg/m2 |
Sodium dodecylbenzenesulfonate |
1 mg/m2 |
Sodium dihexyl-α-sulfosuccinato |
4 mg/m2 |
Preparation of Undercoated Support
[0245] Both surfaces of the above-prepared biaxially stretched polyethylene terephthalate
support having a film thickness of 175 µm were subjected to corona discharge treatment,
then the above undercoating solution prescription (1) was coated by means of a wire
bar in a wet coating amount of 6 ml/m
2 (per one surface side) and dried at 180°C for 5 minutes. Subsequently, one surface
(photosensitive layer side) was subjected to corona discharge treatment, then the
above undercoating solution prescription (2) was coated by means of a wire bar in
a wet coating amount of 9 ml/m
2 and dried at 180°C for 5 minutes. The back surface was coated with undercoating solution
prescription (3) by means of a wire bar in a wet coating amount of 5 ml/m
2 and dried at 180°C for 6 minutes. Thus, the undercoated support was prepared.
Preparation of Back Coating Solution
Preparation of Solid Fine Particle Dispersion Solution (a) of Base Precursor
[0246] A base precursor compound 11 shown below (64 g), 28 g of a diphenylsulfone compound
12 shown below, and 10 g of surfactant Demol N (manufactured by Kao Corporation) were
mixed with 220 ml of distilled water. The mixed solution was dispersed using beads
in a sand mill (1/4 Gallon sand grinder mill, manufactured by Imex Co., Ltd.), thereby
a solid fine particle co-dispersion solution (a) of the base precursor compound and
the diphenylsulfone compound having an average particle size of 0.2 µm was obtained.
Preparation of Solid Fine Particle Dispersion Solution of Dye
[0247] Cyanine dye compound 13 shown below (9.6 g) and 5.8 g of sodium p-alkylbenzenesulfonate
were mixed with 305 ml of distilled water. The mixed solution was dispersed using
beads in a sand mill (1/4 Gallon sand grinder mill, manufactured by Imex Co., Ltd.),
thereby a solid fine particle dispersion solution of the dye having an average particle
size of 0.2 µm was obtained.
Preparation of Antihalation Layer Coating Solution
[0248] PVA-217 (17 g), 9.6 g of polyacrylamide, 70 g of the above solid fine particle dispersion
solution (a) of the base precursor, 56 g of the above solid fine particle dispersion
solution of the dye, 1.5 g of polymethyl methacrylate fine particles (average particle
size: 6.5 µm), 2.2 g of sodium polyethylenesulfonate, 0.2 g of a coloring dye compound
14, and 844 ml of H
2O were mixed. Thus, an antihalation layer coating solution was prepared.
Preparation of Back Surface Protective Layer Coating Solution
[0249] To a reaction vessel maintained at 40°C were added and mixed 50 g of PVA-117, 0.2
g of sodium polystyrenesulfonate, 2.4 g of N,N'-ethylenebis(vinyl sulfone acetamide),
1 g of sodium t-octylphenoxyethoxyethanesulfonate, 30 mg of compound 15, 32 mg of
C
8F
17SO
3K, 64 mg of C
8F
17SO
2N(C
3H
7)(CH
2CH
2O)
4(CH
2)
4-SO
3Na, 8.8 g of acrylic acid/ethyl acrylate copolymer (copolymerization weight ratio:
5/95), and 950 ml of H
2O to prepare a back surface protective layer coating solution.
Preparation of Photothermographic (Photosensitive) Material
[0250] On the back side surface of the above-undercoated polyethylene terephthalate support,
antihalation layer coating solution and the back surface protective layer coating
solution were simultaneously coated and dried in such a manner that the coating amount
of the solid content of the solid fine particle dye of antihalation layer coating
solution became 0.04 g/m
2 and the PVA coating amount of the back surface protective layer coating solution
became 1 g/m
2, thereby an antihalation backing layer was prepared.
[0251] The emulsion layer, the interlayer, the first protective layer and the second protective
layer were simultaneously multilayer-coated by slide bead coating on the opposite
side of the backing layer side in this order from the undercoating side, thereby photothermographic
(photosensitive) material Sample was prepared.
[0252] Coating speed was 160 m/min. The distance between the tip of the coating die and
the support was 0.18 mm. The pressure in the low pressure chamber was set lower than
atmospheric pressure by 392 Pa. In the subsequent chilling zone, air of dry-bulb temperature
of 18°C and wet-bulb temperature of 12°C was blown for 30 seconds. After the coating
solution was dried, dry air of dry-bulb temperature of 30°C and wet-bulb temperature
of 18°C was blown at helical floating type drying zone for 200 seconds. The sample
was then passed through drying zone at 70°C for 30 seconds, and then cooled to 25°C,
thereby the solvent in the coating solution was evaporated. In the chilling zone and
drying zone, the average wind speed was 7 m/sec.
Evaluation of Silver Tone Due to Variation of Heat Development Condition
[0253] The sample of photothermographic photosensitive material prepared was subjected to
stepwise gradation exposure with laser beams vertically multiplied by applying high
frequency convolution using a semiconductor laser emitting at 660 nm. Then, heat development
was performed for 20 seconds at temperatures of 117°C, 120°C and 123°C with heat developing
device 10 of a plate heater type described in Fig. 1 in JP-A-11-133572, and the difference
of silver tone due to variation of heat development condition was evaluated visually
according to the following criteria. The sample was deodorized with metal mesh and
an active carbon filter.
L: Difference of silver tone due to temperature condition is large and impracticable.
M: Difference of silver tone due to temperature condition is observed but in allowable
range.
S: Difference of silver tone due to temperature condition is not observed and good.
Evaluation of Storage Stability
[0254] Difference in Dmin between the sample of the prepared photothermographic photosensitive
material which was allowed to stand at 35°C 70% RH for 7 days and a sample which was
refrigerated for 7 days was measured. Each sample was subjected to stepwise gradation
exposure with a semiconductor laser emitting at 660 nm not applying high frequency
convolution. Then, heat development was performed for 20 seconds at 120°C with the
same heat developing device 10. Difference in Dmin was expressed as the difference
in measured V value of Macbeth densitometer.
[0255] The results obtained are shown in Tables II-1 and II-2. In Table II-1, samples in
which gelatin is used as the main binder in the first and second layers are shown,
and in Table II-2, samples in which PVA is used as the main binder in the first and
second layers are shown.
TABLE II-1
Series using gelatin in the first and second protective layers |
Sample No. |
Shape of Silver Behenate |
Toning Agent |
Storage Stability |
Silver Tone Difference |
101 (Comparison) |
Acicular |
Phthalic acid |
0.44 |
L |
102 (Comparison) |
Acicular |
Ammonium phthalate |
0.41 |
L |
103 (Comparison) |
Acicular |
Sodium phthalate |
0.40 |
L |
104 (Comparison) |
Acicular |
Potassium phthalate |
0.42 |
L |
105 (Comparison) |
Acicular |
I-3 |
0.40 |
L |
106 (Comparison) |
Acicular |
I-4 |
0.41 |
L |
107 (Comparison) |
Acicular |
I-11 |
0.44 |
L |
108 (Comparison) |
Scaly |
Phthalic acid |
0.12 |
L |
109 (Invention) |
Scaly |
Ammonium phthalate |
0.07 |
S |
110 (Invention) |
Scaly |
Sodium phthalate |
0.08 |
M |
111 (Invention) |
Scaly |
Potassium phthalate |
0.08 |
M |
112 (Invention) |
Scaly |
Lithium phthalate |
0.07 |
M |
113 (Invention) |
Scaly |
I-3 |
0.07 |
S |
114 (Invention) |
Scaly |
I-4 |
0.08 |
M |
115 (Invention) |
Scaly |
I-11 |
0.08 |
M |
116 (Invention) |
Scaly |
I-6 |
0.07 |
M |
117 (Invention) |
Scaly |
I-22 |
0.07 |
S |
118 (Invention) |
Scaly |
I-13 |
0.07 |
S |
119 (Invention) |
Scaly |
II-3 |
0.07 |
M |
120 (Invention) |
Scaly |
II-30 |
0.08 |
M |
TABLE II-2
Series using PVA in the first and second protective layers |
Sample No. |
Shape of Silver Behenate |
Toning Agent |
Storage Stability |
Silver Tone Difference |
201 (Comparison) |
Acicular |
Phthalic acid |
0.39 |
L |
202 (Comparison) |
Acicular |
Ammonium phthalate |
0.36 |
L |
203 (Comparison) |
Acicular |
Sodium phthalate |
0.36 |
L |
204 (Comparison) |
Acicular |
Potassium phthalate |
0.36 |
L |
205 (Comparison) |
Acicular |
I-3 |
0.35 |
L |
206 (Comparison) |
Acicular |
I-4 |
0.36 |
L |
207 (Comparison) |
Acicular |
I-11 |
0.37 |
L |
208 (Comparison) |
Scaly |
Phthalic acid |
0.11 |
L |
209 (Invention) |
Scaly |
Ammonium phthalate |
0.06 |
S |
210 (Invention) |
Scaly |
Sodium phthalate |
0.07 |
M |
211 (Invention) |
Scaly |
Potassium phthalate |
0.07 |
M |
212 (Invention) |
Scaly |
Lithium phthalate |
0.07 |
M |
213 (Invention) |
Scaly |
I-3 |
0.06 |
S |
214 (Invention) |
Scaly |
I-4 |
0.07 |
M |
215 (Invention) |
Scaly |
I-11 |
0.07 |
M |
216 (Invention) |
Scaly |
I-6 |
0.07 |
M |
217 (Invention) |
Scaly |
I-22 |
0.06 |
S |
218 (Invention) |
Scaly |
I-13 |
0.06 |
S |
[0256] From the results in Tables II-1 and II-2, the effect of the present invention is
apparent. Samples according to the present invention are excellent in photographic
properties.
EXAMPLE II-2
[0257] Samples were prepared in the same manner as in Examples II-1 except that the content
of stearic acid was varied (shown in Table II-3) when scaly organic acid silver was
prepared, and evaluated in the same manner as in Example II-1. The results obtained
are shown in Table II-3. In any sample, PVA was used as the main binder in the first
and second protective layers.
TABLE II-3
Series using PVA in the first and second protective layers |
Sample No. |
Content of Silver Behenate (mol%) (remaining is silver stearate) |
Toning Agent |
Storage Stability |
Silver Tone Difference |
301 (Comparison) |
100 |
Phthalic acid |
0.11 |
L |
302 (Invention) |
100 |
Ammonium phthalate |
0.06 |
S |
303 (Invention) |
100 |
Sodium phthalate |
0.07 |
M |
304 (Invention) |
100 |
I-3 |
0.06 |
S |
305 (Invention) |
100 |
I-11 |
0.06 |
M |
306 (Comparison) |
95 |
Phthalic acid |
0.12 |
L |
307 (Invention) |
95 |
Ammonium phthalate |
0.07 |
S |
308 (Invention) |
95 |
Sodium phthalate |
0.08 |
M |
309 (Invention) |
95 |
I-3 |
0.07 |
S |
310 (Invention) |
95 |
I-11 |
0.07 |
M |
311 (Comparison) |
85 |
Phthalic acid |
0.26 |
S |
312 (Invention) |
85 |
Ammonium phthalate |
0.20 |
S |
313 (Invention) |
85 |
Sodium phthalate |
0.22 |
S |
314 (Invention) |
85 . |
I-3 |
0.20 |
S |
315 (Invention) |
85 |
I-11 |
0.20 |
S |
316 (Comparison) |
75 |
Phthalic acid |
0.38 |
S |
317 (Invention) |
75 |
Ammonium phthalate |
0.32 |
S |
318 (Invention) |
75 |
Sodium phthalate |
0.31 |
S |
319 (Invention) |
75 |
I-3 |
0.31 |
S |
320 (Invention) |
75 |
I-11 |
0.31 |
S |
[0258] The results in Table II-3 indicate that the storage stability is improved by increasing
the content of silver behenate.
EXAMPLE II-3
[0259] Samples were prepared in the same manner as in Examples II-1 and II-2 except that
SBR latex used in emulsion layers was not purified.
[0260] The same results as in Examples II-1 and II-2 were obtained.
EXAMPLE II-4
[0261] Samples were prepared in the same manner as in Example II-1 except that latexes Lb1
and Lc1 (equilibrium moisture content at 25°C 60% RH was less than 2 wt% with both
Lb1 and Lc1) shown below were used in place of SBR latex used in emulsion layers.
[0262] The same results as in Example II-1 were obtained.
Synthesis of Lb1
[0263] Into a glass autoclave (TEM-V1000, manufactured by Taiatsu Glass Kogyo Co., Ltd.)
were put 140 g of styrene, 280 g of distilled water, 4.44 g of a surfactant (Sandet
BL, manufactured by Sanyo Kasei Co., Ltd.), and 6 g of acrylic acid, and the content
was stirred for 1 hour in a nitrogen atmosphere. Thereafter, 54 g of 2-ethylhexyl
acrylate was added to the reaction mixture and the temperature was raised to 70°C.
Then, 20 g of a 5 wt% aqueous ammonium persulfate solution was added thereto and stirring
was continued for 10 hours. After stirring was finished, the temperature of the reaction
vessel was lowered to room temperature, thereby a styrene-acryl latex was obtained.
1 N aqueous ammonia was added to this latex to adjust pH to 7.5.
[0264] Thus, latex Lb1 having an average particle diameter of 98 nm and concentration of
42 wt% was obtained. Equilibrium moisture content of the polymer at 25°C 60% RH was
0.7 wt%.
Synthesis of Lc1
[0265] Into a glass autoclave (TEM-V1000, manufactured by Taiatsu Glass Kogyo Co., Ltd.)
were put 126 g of methyl methacrylate, 280 g of distilled water, 8.2 g of a surfactant
(Sandet BL, manufactured by Sanyo Kasei Co., Ltd.), and 4 g of acrylic acid, and the
content was stirred for 1 hour in a nitrogen atmosphere. Thereafter, 70 g of ethyl
acrylate was added to the reaction mixture and the temperature was raised to 60°C.
Then, 20 g of a 5 wt% aqueous potassium persulfate solution was added thereto and
stirring was continued for 10 hours. After stirring was finished, the temperature
of the reaction vessel was lowered to room temperature, thereby an acryl latex was
obtained. 1 N aqueous ammonia was added to this latex to adjust pH to 7.5.
[0266] Thus, latex Lc1 having an average particle diameter of 101 nm and concentration of
44 wt% was obtained. Equilibrium moisture content of the polymer at 25°C 60% RH was
0.7 wt%.
EXAMPLE II-5
[0267] Samples were prepared in the same manner as in Examples II-1 to II-4 except that
photosensitive silver halide was excluded. The obtained samples were heated to 100°C
or more with a thermosensitive type thermal head (maximum temperature: 230°C). The
same results as in Examples II-1 to II-4 were obtained.
EFFECT OF THE INVENTION
[0268] According to the method of the present invention, the storage stability of a coated
bulk product and silver tone can be improved.