TECHNICAL FIELD
[0001] The present invention relates to a polyester monofilament suitable for high-mesh
woven fabrics for screen mesh cloth applications. More specifically, the present invention
relates to a polyester monofilament for a screen mesh cloth suitable for direct digital
platemaking, which is a novel high-definition printing technique which performs direct
platemaking and printing by digital processing using a computer and in which a positive
film is not used and a dyeing process is not required.
BACKGROUND ART
[0002] Conventionally, as a fabric for screen printing, a woven mesh fabric made of natural
fibers or inorganic fibers has been widely used. However, in recent years, synthetic
meshes which are excellent in flexibility, durability, and cost performance, particularly
woven mesh fabrics made of polyester among those are widely used, and are used in
a wide range of applications, such as textile printing, identification printing, high
accuracy printing of graphic designs such as label printing of compact discs, electronic
substrate circuit printing, and the like. With improvements of functionality and compactness
of electronic devices accelerated in recent years, the substrate circuit have also
become more precise and compact, and it is strongly required that the screen mesh
cloth has high printing accuracy.
[0003] In order to satisfy the required characteristics such as the improvement in printing
accuracy, the strength and the modulus of the monofilament as the constituent elements
have been increased. On the other hand, the technical revolution is advanced also
in the platemaking process. In a common screen printing, a gray fabric obtained by
warping and weaving is dyed in yellow to inhibit halation, and a processed cloth is
produced by heat setting. This processed cloth is applied to a plate frame with high
tension, and a photosensitive emulsion mainly composed of diazo-based compounds is
applied, and then the positive film and the plate are pressed to be bonded in an exposure
process, and the photosensitive emulsion is solidified by ultraviolet irradiation.
After that, an unsolidified portion of the photosensitive emulsion is removed and
a negative is prepared, and the plate frame is filled with the coating material and
then the coating agent is applied to the object by squeezing to perform printing.
In the platemaking/printing process, the most important process from the viewpoint
of printing accuracy is an alignment process of the positive film and the printing
plate. While the alignment of the positive film and the printing plate directly influences
the printing accuracy, the alignment operation is largely dependent on the experience,
knowledge, and sensation of the operator, and a large number of artificial factors
tend to cause variations.
[0004] In order to solve this problem, a new platemaking and printing technique called direct
digital platemaking has been developed. Direct digital platemaking is a platemaking/printing
technique in which a printing pattern is digitized by a computer, a photosensitive
emulsion on a platemaking surface is treated with a laser based on optical output,
and a pattern is formed on a printing plate by direct exposure. Since the printing
pattern is directly formed by the computer, a positive film is not necessary and thus
the cost of the positive film can be reduced, and the alignment with the positive
film is eliminated so that the printing accuracy is improved as compared with the
conventional screen printing method.
[0005] In addition, in a common screen printing method, since halation occurs in the exposure
process and the photosensitive emulsion curing process so that the printing accuracy
is lowered, a treatment for preventing halation has been indispensable. For example,
in Patent Literatures 1 and 2, which disclose typical monofilaments for a screen mesh
cloth, titanium oxide, which is also known as a matting agent, is contained, and the
screen mesh cloth is dyed in yellow in the dyeing process to prevent halation. On
the other hand, in addition to titanium oxide, there are cases in which a chemical
substance for preventing halation is contained in the polymer itself. In Patent Literature
3, a spun-dyed monofilament in which an organic compound-based yellow pigment is contained
in a polymer has been proposed, and in addition to the effect of preventing halation,
a dyeing process is not required, so that the environmental load can be reduced. In
addition, in Patent Literature 4, an ultraviolet absorbent is contained in the polymer,
the screen mesh cloth is dyed in yellow, and the exposure and the photosensitive emulsion
curing are performed to improve the effect of preventing halation.
[0006] In this manner, in the common screen printing method, it is necessary to contain
titanium oxide and to make the screen mesh cloth yellow in order to prevent halation.
On the other hand, this is not the case with a multifilament for clothing. As disclosed
in Patent Literature 5, for example, a woven fabric for clothing having high transparency
and excellent esthetics by reducing the content of titanium oxide has been proposed.
CITATION LIST
PATENT LITERATURE
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0008] As described above, in the common screen printing, a treatment for preventing halation
during exposure and photosensitive emulsion curing is indispensable. On the other
hand, in direct digital platemaking, there is no restriction on the content of titanium
oxide and the color of the screen mesh cloth since the influence of halation is small.
As a result, the curing time of the photosensitive emulsion can be significantly shortened
by using the transparent raw yarn excellent in transparency for a laser to be used
during exposure for the screen mesh cloth. By shortening the curing time of the photosensitive
emulsion, the platemaking process can be made more efficient, and high accuracy printing
can be performed in a short time. From this viewpoint, as a monofilament for a screen
mesh cloth used in direct digital platemaking, a transparent bright monofilament having
excellent laser transparency is preferable.
[0009] In the monofilaments described in Patent Literatures 1 and 2, titanium oxide is contained
as described above, and the screen mesh cloth is dyed in yellow in the dyeing process.
In this case, since titanium oxide and the dye hinder the laser transmission, it is
difficult to say that the monofilaments are suitable for direct digital platemaking.
In Patent Literature 3, in addition to titanium oxide, an organic compound-based pigment
is contained, but it is difficult to say that it is suitable for direct digital platemaking
from the viewpoint of inhibiting the laser transmission. In Patent Literature 4, in
addition to the fact that the yellow dye hinders the laser transmission, the strength
and modulus of the screen mesh cloth are reduced due to shrinkage during dyeing, so
that the dimensional stability and the printing accuracy of the screen mesh cloth
are reduced. Therefore, it is also difficult to say that it is suitable for the direct
digital platemaking, in which there is no restriction on the color of the screen mesh
cloth.
[0010] Although the multifilament for clothing disclosed in Patent Literature 5 has a reduced
titanium oxide content in order to improve transparency and esthetics, a screen mesh
cloth has a higher quality requirement than a woven fabric for clothing, and even
if the technique described in Patent Literature 5 is applied to a monofilament for
a screen mesh cloth, the monofilament cannot withstand the abrasion resistance with
the reed in weaving. That is, since the content of metal particles to form fine unevenness
on the surface of the fiber, such as titanium oxide, is small, the friction coefficient
between the raw yarn and the metal is high, and it is obvious that printing defects
such as fluffing, scum or the like are caused in weaving. In addition, since a multifilament
has poor uniformity of the fiber diameter compared with a monofilament, it is not
preferable as a raw yarn for the screen mesh cloth.
[0011] In order to obtain a bright monofilament which is suitable for direct digital platemaking,
it is important to impart excellent transparency to the raw yarn and at the same time
to reduce fluffing and scum defects in the weaving.
[0012] Therefore, an object of the present invention is to provide a monofilament which
is suitable for direct digital platemaking, in which a positive film is not used and
direct platemaking is performed without a dyeing process, excellent in laser transparency
so that an emulsion curing time can be shortened, and also excellent in higher order
passability in a weaving process.
SOLUTION TO PROBLEM
[0013] In order to achieve the above object, the present invention includes any one of the
following configurations (1) to (3).
- (1) A polyester monofilament for a screen mesh cloth, the polyester monofilament having:
a transmittance of 30% or more when the polyester monofilament is irradiated with
a wavelength of 405 nm; a breaking strength of 4.3 cN/dtex to 9.0 cN/dtex; a breaking
elongation of 11.0% to 50.0%; and a 10% modulus of 2.5 cN/dtex to 9.0 cN/dtex.
- (2) The polyester monofilament for a screen mesh cloth according to (1), in which
a coefficient of dynamic friction between a raw yarn and a satin metal is 0.100 to
0.170.
- (3) A woven mesh fabric for direct digital platemaking, in which the polyester monofilament
according to (1) or (2) is disposed on at least a part of at least one of a warp and
a weft.
ADVANTAGEOUS EFFECTS OF INVENTION
[0014] According to the present invention, the monofilaments of the present invention having
excellent transparency at a wavelength of 405 nm used for exposure can be suitably
used for direct digital platemaking, and the emulsion curing time can be shortened,
high-definition screen printing can be performed in a short time, and printing defects
such as fluffing and scum occurring during weaving can be reduced.
BRIEF DESCRIPTION OF DRAWINGS
[0015]
[FIG. 1] FIG. 1 is a schematic view for illustrating a sample preparation method when
measuring a transmittance of the polyester monofilament for a screen mesh cloth of
the present invention.
[FIG. 2] FIG. 2 is a schematic view for illustrating a method of measuring the dynamic
friction coefficient between a raw yarn and a satin metal in the polyester monofilament
for a screen mesh cloth of the present invention.
[FIG. 3] FIG. 3 is a schematic view showing an example of a spinning device in a two-step
method used in the present invention.
[FIG. 4] FIG. 4 is a schematic view showing an example of a drawing device in the
two-step method used in the present invention.
[FIG. 5] FIG. 5 is a schematic view showing an example of a yarn production device
in a one-step method (direct spinning drawing method) used in the present invention.
DESCRIPTION OF EMBODIMENTS
[0016] The polyester monofilament for a screen mesh cloth of the present invention is a
polyester monofilament containing polyethylene terephthalate as a main component.
Here, the term "main component" refers to a component that occupies 60 wt% or more
of all components, and "containing polyethylene terephthalate as a main component"
indicates that polyethylene terephthalate is contained at 60 wt% or more with respect
to the resin components constituting the monofilament.
[0017] The polyester monofilament for a screen mesh cloth of the present invention has a
transmittance of 30% or more when irradiated with a wavelength of 405 nm for a monofilament
wound uniformly in a certain direction at a density of 0.018 g/cm
2 on a transparent acrylic plate having a thickness of 2 mm.
[0018] FIG. 1 is a schematic view for illustrating a sample preparation method when measuring
a transmittance of the polyester monofilament for a screen mesh cloth of the present
invention.
[0019] As shown in FIG. 1, a transparent acrylic plate 1 having a thickness of 2 mm is placed
in an aligned winding evaluation device 2, and the transparent acrylic plate 1 is
rotated while being traversed. The monofilament Y that has been unwound and run through
a nip roll 4, a tensor 5, a direction change roll 6, and a yarn path regulation guide
7 are wound around the transparent acrylic plate 1 uniformly in a certain direction
at a density of 0.018 g/cm
2 via an unwinding guide 3, thereby producing a plate-wound sample 8. Thereafter, after
the plate-wound sample 8 is placed on the spectrophotometer, the transmittance T1
of the plate-wound sample 8 for a wavelength of 405 nm of the laser used for emulsion
curing is measured. On the other hand, since the transparent acrylic plate 1 alone
exhibits constant absorption for the wavelength of 405 nm, the transmittance (T0 =
10%) of the transparent acrylic plate 1 alone at 405 nm is measured, and the transmittance
(T2) of the polyester monofilament for a screen mesh cloth at 405 nm is calculated
according to the following formula (1).

[0020] As a result of intensive studies by the present inventors, it has been found that
it is important for the polyester monofilament for a screen mesh cloth used in direct
digital platemaking to have a transmittance of 30% or more for a wavelength of 405
nm. By using a monofilament having a transmittance of 30% or more, the emulsion curing
time can be shortened when irradiated with the laser required for emulsion curing,
and screen printing with high accuracy can be performed in a short time. When the
transmittance is lower than 30%, emulsion curing is insufficient in a short time,
and printing cannot be performed in a designed pattern in some cases. A more preferable
transmittance of the monofilament when irradiated with a wavelength of 405 nm is 35%
or more. The upper limit of the transmittance is not particularly limited, but the
transmittance is preferably 80% or less, and more preferably 70% or less, from the
viewpoint of higher order passability in the weaving process.
[0021] In order to obtain such a monofilament having a high transmittance at a wavelength
of 405 nm, for example, it is preferable to use a bright polyester in which the content
of titanium oxide contained in the polyester is reduced. Although bright monofilaments
having high transmittance can be obtained by other methods, it is preferable to minimize
the content of titanium oxide commonly known as a matting agent, and the content of
titanium oxide is preferably 0.030 wt% or less, more preferably 0.027 wt% or less.
[0022] The polyester monofilament for a screen mesh cloth of the present invention is formed
of a polyethylene terephthalate which contains terephthalic acid as a main acid component
and ethylene glycol as a main glycol component and 90 mol% or more of which is composed
of a repeating unit of ethylene terephthalate. However, the polyester monofilament
may include a copolymerization component capable of forming another ester bond at
a ratio of less than 10 mol%, as long as the transmittance at a wavelength of 405
nm, which is a feature of the present invention, is not inhibited. In addition, a
metal catalyst, an inorganic particle, a lubricant, an antioxidant, a flame retardant,
an antistatic agent, or the like can be added to the polyethylene terephthalate as
necessary within a range that does not impair the transmittance which is a feature
of the present invention.
[0023] The intrinsic viscosity of the yarn in the polyester monofilament for a screen mesh
cloth of the present invention is preferably 0.60 to 0.90, and more preferably 0.60
to 0.82, from a viewpoint of the strength and the yarn production stability of the
obtained monofilaments.
[0024] The cross-sectional form of the yarn in the polyester monofilament for a screen mesh
cloth of the present invention can be either a single component or a core-sheath composite.
However, since the laser may be reflected and scattered at the interface of the core
sheath in the case of the core-sheath composite yarn, the monofilament is preferably
a single component yarn.
[0025] The polyester monofilament for a screen mesh cloth of the present invention has a
breaking strength of 4.3 cN/dtex to 9.0 cN/dtex and a breaking elongation of 11.0%
to 50.0%. In the case where the strength is too high and the elongation is too low,
the process passability in yarn production and weaving is lowered and yarn breakage
occurs frequently, so that the breaking strength is 9.0 cN/dtex or less and the breaking
elongation is 11.0% or more, preferably the breaking strength is 6.2 cN/dtex or less
and breaking elongation is 25.0% or more. Further, in the case where the strength
is too low and the elongation is too high, when the monofilament is processed into
a screen mesh cloth, a cloth stretch occurs and excellent dimensional stability may
not be obtained and the printing accuracy may be lowered. Therefore, the breaking
strength is set to 4.3 cN/dtex or more and the breaking elongation of 50.0% or less.
[0026] The polyester monofilament for a screen mesh cloth of the present invention has a
10% modulus of 2.5 cN/dtex to 9.0 cN/dtex. In the case where the 10% modulus is too
low, the cloth stability may not be obtained, and the printing accuracy may be lowered.
On the other hand, in the case where the 10% modulus is too high, the surface of the
fiber becomes highly oriented, and it may be difficult to inhibit fluffing defects
and scum defects that occur during weaving. Therefore, the 10% modulus is from 2.5
cN/dtex to 9.0 cN/dtex and the preferred 10% modulus is from 2.8 cN/dtex to 5.0 cN/dtex.
[0027] The single fiber fineness of the polyester monofilament for a screen mesh cloth of
the present invention is preferably 65.0 dtex or less from the needs for screen mesh
cloth use, and preferably 4.0 dtex or more from a standpoint of the yarn production
property. More preferably, the single fiber fineness thereof is from 8.0 dtex to 62.0
dtex.
[0028] The boiling water shrinkage rate of the polyester monofilament for a screen mesh
cloth of the present invention is preferably 5.0% to 12.0%. In the case where the
crystallization of the monofilament excessively proceeds, although the boiling water
shrinkage rate decreases, the yarn may be whitened due to the proceeding of excessive
crystallization. In this case, since the transmittance with respect to the wavelength
of 405 nm which is a feature of the present invention may be inhibited, the boiling
water shrinkage rate is preferably 5.0% or more. Further, when the boiling water shrinkage
rate is within 12.0%, dimensional stability during heat setting can be obtained, and
therefore the boiling water shrinkage rate is preferably within 12.0%. More preferably,
the boiling water shrinkage rate is 6.0% to 10.0%.
[0029] The dynamic friction coefficient between the raw yarn and the satin metal (hereinafter,
also referred to as the dynamic friction coefficient between the raw yarn and the
satin metal) in the polyester monofilament for a screen mesh cloth of the present
invention is preferably 0.100 to 0.170. The satin metal is a metal having fine unevenness
on the surface, and in the present invention, the dynamic friction coefficient between
the original yarn and the satin metal having a surface roughness of 6S is measured.
By setting the dynamic friction coefficient between the raw yarn and the satin metal
to 0.170 or less, it is possible to reduce the abrasion of the surface of the yarn
due to the abrasion resistance with the reed in the weaving, to reduce the printing
defects due to the fluffing defects on the shavings and the powdery scum defects,
and to improve the printing accuracy of the screen mesh cloth. For example, in a bright
monofilament in which the content of inorganic particles such as titanium oxide having
a function as a lubricant is minimized, it is important to reduce the dynamic friction
coefficient between the raw yarn and the satin metal and to improve the process passability
in weaving, and the dynamic friction coefficient between the raw yarn and the satin
metal is preferably 0.170 or less. On the other hand, in the case where the dynamic
friction coefficient between the raw yarn and the satin metal is 0.100 or more, it
is possible to inhibit a decrease in the process passability due to insufficient tension
in the yarn production process and the weaving process. Therefore, the dynamic friction
coefficient between the raw yarn and the satin metal is preferably 0.100 or more.
More preferably, the dynamic friction coefficient between the raw yarn and the satin
metal is 0.130 or more.
[0030] In addition, an oil adhesion amount of the drawn yarn in the polyester monofilament
for a screen mesh cloth of the present invention is preferably 0.10 wt% to 0.70 wt%.
By setting the oil adhesion amount to 0.10 wt% or more, it is possible to inhibit
an increase in the dynamic friction coefficient between the raw yarn and the satin
metal, and to reduce the fluffing defects and scum defects caused by insufficient
formation of an oil film. On the other hand, by setting the oil adhesion amount to
0.70 wt% or less, it is possible to inhibit the oil from falling off due to abrasion
with the reed in the weaving process, thereby reducing the scum defects. Therefore,
the oil adhesion amount is preferably 0.10 wt% to 0.70 wt%, and more preferably 0.10
wt% to 0.50 wt%.
[0031] Next, a method for producing the polyester monofilament for a screen mesh cloth of
the present invention will be described. The spinning method of the polyester monofilament
of the present invention is not particularly limited, and common techniques can be
used. For example, after the polyethylene terephthalate is subjected to melt extrusion
and the polyethylene terephthalate is filtered in a predetermined spinning pack, the
yarn discharged from a spinneret is solidified by cooling air, and after an oil agent
is applied by an oil feed roll, the yarn is taken up via a godet roll to obtain an
undrawn yarn. The undrawn yarn may be processed in a two-step method in which the
undrawn yarn is wound once and then drawn by a drawing machine, or may be processed
in a one-step method (direct spinning drawing method) in which the undrawn yarn is
continuously drawn without once winding. For the purpose of inhibiting the orientation
of the fiber surface, the fiber discharged from the spinneret may be passed through
a heat-insulating cylinder that has been actively heated.
[0032] In the oil agent applied to the polyester monofilament for a screen mesh cloth of
the present invention, as an oil component concentration excluding water in the emulsion,
a fatty acid alkyl ester-based smoothing agent is preferably contained in an amount
of 45 wt% to 65 wt%, more preferably 50 wt% to 60 wt% from the viewpoint of higher
order passability. For example, in a bright polyester monofilament in which the content
of inorganic particles such as titanium oxide having a function as a lubricant is
minimized, compared to a typical polyester monofilament for a screen mesh cloth, it
is difficult to form fine unevenness on the fiber surface. Therefore, the dynamic
friction coefficient between the raw yarn and the satin metal increases, and it is
difficult to inhibit fluffing defects and scum defects caused by abrasion resistance
with the reed in weaving only by adding the fatty acid alkyl ester-based smoothing
agent.
[0033] Then, in the case where a modified silicone product, which is a smoothing agent,
is contained in the emulsion in an amount of 6 wt% to 8 wt% in terms of the oil component
concentration excluding moisture, the dynamic friction coefficient between the raw
yarn and the satin metal can be reduced. In the case where 6 wt% or more of the modified
silicone product is contained, it is possible to reduce the dynamic friction coefficient
between the raw yarn and the satin metal in the bright polyester monofilament such
that the bright polyester monofilament can withstand the abrasion resistance with
the reed in the weaving. On the other hand, if the content of the modified silicone
product exceeds 8 wt%, the dynamic friction coefficient between the raw yarn and the
satin metal may not be reduced further, and the effect of reducing the dynamic friction
coefficient between the raw yarn and the satin metal may not be obtained anymore.
In the case where the content of the modified silicone product is 8 wt% or less, it
is possible to inhibit destabilization of an oil film on an oil feed roller due to
a decrease in surface tension and a decrease in uniform adhesion of an oil agent,
and thus fluffing and scum defects can be prevented. Therefore, in the bright polyester
monofilament, the content of the modified silicone product contained in the emulsion
is preferably 6 wt% to 8 wt%, more preferably 7 wt% to 8 wt%, in terms of the oil
component concentration excluding moisture.
[0034] Antistatic agents such as alkyl sulfonate, extreme pressure agents such as alkyl
phosphate, oil film reinforcing agents, emulsifiers, pH adjusters, preservatives or
the like may be added to the oil agent applied to the polyester monofilament of the
present invention as long as the smoothness is not impaired.
[0035] The emulsion concentration of the oil agent applied to the polyester monofilament
of the present invention is preferably 2 wt% to 12 wt%, more preferably 2 wt% to 10
wt%, from the viewpoint of the scattering of the oil and the stability of the oil
film on the oil feed roller.
[0036] The spinning speed of the polyester monofilament of the present invention, that is,
the speed of the godet roll used to obtain the undrawn yarn, is preferably 500 m/min
to 1,300 m/min. In the case where the speed of the godet roll is 500 m/min or more,
it is possible to stabilize the runnability of the yarn, and in the case where the
speed of the godet roll is 1,300 m/min or less, it is possible to inhibit the fiber
surface orientation before drawing from being promoted and reduce fluffing and scum
defects caused as a result thereof. A more preferred spinning speed is 700 m/min to
1,200 m/min.
[0037] The method of drawing the polyester monofilament of the present invention is not
particularly limited, and may be based on a common technique, for example, after one-stage
heating drawing between a first hot roll and a second hot roll, the yarn is wound
through a cold godet roll to obtain a drawn yarn. In addition, instead of the one-stage
heating drawing, a two-stage heating drawing method may be employed in which the first-stage
heating drawing is performed between the first hot roll and the second hot roll, and
the second-stage heating drawing is performed between the second hot roll and a third
hot roll.
[0038] As for the temperature in drawing of the polyester monofilament of the present invention,
the temperature of the first hot roll is preferably within a range of from the glass
transition temperature +10°C to the glass transition temperature +30°C of the polyester
as the core component, and the temperature of the second hot roll is preferably within
a range of 130°C to 200°C in a case of the first-stage heating drawing. In the case
where the temperature of the second hot roll is 130°C or higher, the fiber orientation
can be controlled to promote crystallization of the fiber, thereby increasing the
strength of the yarn. On the other hand, in the case where the temperature of the
second hot roll is 200°C or lower, not only the yarn production property is good but
also whitening of the yarn due to the promotion of excessive crystallization can be
inhibited. A more preferred temperature of the second hot roll is 130°C to 150°C.
[0039] The draw ratio of the polyester monofilament of the present invention is preferably
3.0 times or more in total in order to obtain a target yarn having a high strength
and a high modulus. In addition, in order to inhibit a decrease in the process passability
in the yarn production process and the weaving process, it is necessary to keep room
for elongation of the yarn, and to inhibit the fluffing and scum defects in the weaving.
Therefore, the draw ratio is preferably 6.0 times or less in total. A more preferable
total draw ratio is 3.5 to 5.0 times. Further, in the case of drawing the polyester
monofilament for a screen mesh cloth of the present invention, the filament can be
wound at the same speed between the final hot roll and the cold godet roll, or a relaxing
treatment for setting a speed difference between the two rolls can be performed for
the purpose of preventing orientation of an amorphous portion.
[0040] The woven mesh fabric produced using the polyester monofilament of the present invention
can be suitably used for direct digital platemaking. The polyester monofilament of
the present invention is preferably disposed in at least a part of at least one of
a warp and a weft of the woven mesh fabric, and it is more preferable that at least
one of the warp and the weft of the woven mesh fabric is formed of the polyester monofilament
of the present invention, and it is particularly preferable that both the warp and
the weft be formed by the polyester monofilament of the present invention.
EXAMPLES
[0041] Next, a polyester monofilament for a screen mesh cloth of the present invention will
be described in detail with reference to Examples. The evaluation in Examples was
performed in accordance with the following method.
(1) Transmittance of Monofilament and Woven Mesh Fabric
[0042] As shown in FIG. 1, a transparent acrylic plate 1 having a thickness of 2 mm (manufactured
by MISUMI Group Inc.: Model ACSH series) was placed in an aligned winding evaluation
device 2 manufactured by EIKO Industrial Co., Ltd. The transparent acrylic plate 1
was rotated at 550 rpm while being traversed, and a monofilament Y that had been run
through a nip roll 4, a tensor 5, direction change rolls 6, and a yarn path regulation
guide 7 by applying a tension of 10 g was wound around the transparent acrylic plate
1 for four rounds (eight layers) uniformly in a certain direction at a density of
0.018 g/cm
2 via an unwinding guide 3 to obtain a plate-wound sample 8. The number of rounds in
winding a yarn on the traverse-moved transparent acrylic plate 1 was determined by
the fineness (fiber diameter) of the yarn, and was four rounds (eight layers) in the
case of 32 dtex (54 µm). In the case where a yarn having a different fineness (fiber
diameter) was wound, the number of rounds (number of layers) was adjusted such that
the density of the wound sample was the same. For example, the number of rounds is
eight (16 layers) for 8 dtex (27 µm), five (10 layers) for 20 dtex (43 µm), and nine
(18 layers) for 6 dtex (24 µm).
[0043] Subsequently, the plate-wound sample 8 of the monofilament was placed in a spectrophotometer
(Model SPECTROPHOTOMETER CM-3700d) manufactured by Konica Minolta Co., Ltd., and then
the transmittance T1 of the plate-wound sample 8 at 405 nm, which is the wavelength
of the laser used for emulsion curing, was measured. On the other hand, since the
transparent acrylic plate 1 alone exhibits a certain absorption at a wavelength of
405 nm, the transmittance (T0 = 10%) at 405 nm was similarly measured with the transparent
acrylic plate 1 alone. Using the obtained T0 and T1, the transmittance (T2) of a monofilament
alone at 405 nm was calculated according to the following formula (1).

[0044] On the other hand, for the transmittance of the woven mesh fabric, one woven mesh
fabric was placed in a spectrophotometer in the same manner as described above without
a transparent acrylic plate, and then a transmittance T3 at a wavelength of 405 nm
was measured.
[0045] The transmittance measurement in the spectrophotometer is performed in the measurement
mode: transmission mode, geometry: di = 0°, de = 0°, specular light treatment: SCI,
measurement diameter: LAV (25.4 mm), UV conditions: 100% Full.
(2) Intrinsic Viscosity (IV)
[0046] The intrinsic viscosity (IV) of the yarn in the polyester monofilament was calculated
according to the following formula (2).
[0047] The relative viscosity ηr in the formula (2) was obtained by the following formula
(3) by dissolving 0.8 g of a sample in 10 mL of o-chlorophenol (hereinafter abbreviated
as OCP) having a purity of 98% or more at 25°C and using an Ostwald viscometer at
a temperature of 25°C.

In formula (3),
η: Viscosity of sample solution
η0: Viscosity of OCP
t: Drop time of solution (seconds)
d: Solution density (g/cm3)
t0: Drop time of OCP (seconds)
d0: Solution density (g/cm3).
(3) Glass Transition Temperature (Tg)
[0048] Glass transition temperature Tg (°C) was determined as follows: 10 mg of a powder
of the polyester to be used was collected; the temperature was raised at 16 °C/min
with a differential scanning calorimeter (PerkinElmer Co., Ltd.: DSC-4 type), and
the peak associated with the glass transition developed in the temperature rise process
was processed with a data processing system manufactured by PerkinElmer Co., Ltd.
(4) Strength, Elongation, 10% Modulus
[0049] A Tensilon tensile tester manufactured by ORIENTEC Co., Ltd. was used to measure
the strength, elongation, and modulus at 10% elongation at break at an initial sample
length of 20 cm and a tensile speed of 2 cm/min were measured, and the average value
of the values measured three times was determined as the strength (cN/dtex), elongation
(%), and 10% modulus (cN/dtex), respectively.
(5) Single Fiber Fineness
[0050] The fineness of the monofilament was skeined by 500 m, and the value obtained by
multiplying the mass of the skein by 20 was taken as the fineness.
(6) Boiling Water Shrinkage Rate
[0051] A monofilament was skeined using a measuring machine having a frame circumference
of 100 cm to prepare a skein having 10 turns. A constant load was applied to the obtained
skein, and the initial skein length L0 (mm) was measured. The weight was removed,
immersed in warm water at 100°C for 15 minutes, dried for 30 minutes or more, and
then subjected to a constant load to measure a skein length L1 (mm) after shrinkage,
and the boiling water shrinkage rate (%) was calculated according to the following
formula (4).

[0052] The load (g) applied during measurement of the initial skein length and the skein
length after shrinkage was set according to the following formula (5) based on the
total fineness T (dtex) of the yarn.

(7) Dynamic Friction Coefficient between Raw Yarn and Satin Metal
[0053] By the running yarn method, the yarn was brought into contact with a fixing pin (surface
roughness: 6S (HRMS)) made of satin metal having a diameter d of 35 mm at a contact
angle of θ = 180°, and unwound and run at a yarn speed of 55 m/min. That is, as shown
in FIG. 2, when the monofilament Y unwound from a package (not shown) through an unwinding
guide (not shown) was applied the load N1 (= 10 g) by a balancer 9, then was passed
through a fixing pin 11 made of satin metal through a direction change guide 10, and
was taken up by a take-up roll 14 through a tension meter 13 after passing through
a direction change guide 12, N2 (g) measured by the tension meter 13 was measured
and calculated according to the following formula (6).

(8) Uster Unevenness U% (N)
[0054] A fineness variation chart (Diagram Mass) was obtained under the following measurement
conditions using a Uster Tester UT-4CX manufactured by Zellweger Co., Ltd. without
using a twister, and simultaneously, an average deviation rate (U%) was measured in
the normal mode.
Yarn feeding speed: 200 m/min
Measuring yarn length: 200 m
Disk tension strength: 10%
Scale: -10% to 10%
(9) Screen mesh cloth Quality
[0055] Using each of the polyester monofilaments in Examples and Comparative Examples of
the present invention for both of the warp and the weft, a screen mesh cloth having
a width of 2.2 m and a length of 300 m was woven by a loom made by Sulzer at a loom
rotation speed of 200 rotations/min.
[0056] The obtained screen mesh cloth was caused to run at a speed of 2 m/min, a skilled
inspection technician visually inspected the fluff and scum according to the inspection
rules for a screen mesh cloth, and comprehensively evaluated the fluffing and scum
based on the following four grades. The pass levels are A and B.
- A: The number of fluffing and scum defects is 0 to 1 per 30 m in length
- B: The number of fluffing and scum defects is 2 to 5 per 30 m in length
- C: The number of fluffing and scum defects is 6 to 9 per 30 m in length
- D: The number of fluffing and scum defects is 10 or more per 30 m in length
(10) Printing Accuracy
[0057] The printing evaluation was performed by direct digital platemaking using the screen
mesh cloth. That is, the photosensitive emulsion was applied to the screen mesh cloth
obtained in (9) and then was irradiated with a 405 nm laser for 40 seconds to form
a 50 µm line pattern at intervals of 50 µm. After that, the line accuracy and the
distortion of the printing pattern due to dimensional stability in printing 1000 sheets
were observed, and comprehensively evaluated based on the following four grades. The
pass levels are A, B, and C.
- A: The line accuracy and dimensional stability are extremely good
- B: The line accuracy is extremely good, and dimensional stability is good Alternatively,
the line accuracy is good, and dimensional stability is extremely good
- C: The line accuracy and dimensional stability are good
- D: The line accuracy is good, but dimensional stability is poor
[0058] Alternatively, the line boundary may be uneven, but dimensional stability is good
(Example 1)
[0059] A polyethylene terephthalate (glass transition temperature: 80°C) with a titanium
oxide content of 0.025 wt%, which had been polymerized and chipped by a common method,
was melted at a temperature of 287°C using an extruder (pressure melter), weighed
by a pump, and then flowed into a common single component spinneret. The pipe passage
time of the polymer was 30 minutes, and the pressure applied to the spinneret was
10 MPa. Thereafter, the yarn discharged from the spinneret was spun using a spinning
device equipped with the equipment as shown in FIG. 3. That is, the polyester monofilament
discharged from the spinneret 15 was cooled by applying a cooling air of 20 m/min
by a yarn cooling air blowing device 16, an oil agent having an emulsion concentration
of 4 wt% was applied by an oil feed roll 17, and then was taken up by a non-heated
godet roll 18 at a speed of 900 m/min, thereby obtaining an undrawn yarn package 19.
The oil agent applied to the undrawn yarn contains 54 wt% of a fatty acid alkyl ester
and 7 wt% of a modified silicone product as a smoothing agent, an alkyl phosphate
as an extreme pressure agent, an alkyl sulfonate as an antistatic agent, a nonionic
ester and a nonionic ether as an emulsifier.
[0060] Subsequently, the undrawn yarn package 19 was used to perform drawing using a drawing
device equipped with the equipment as shown in FIG. 4. That is, the yarn passed through
a feed roll 20 was taken over by a first hot roll 21 heated to a temperature of 91°C
at a speed of 174 m/min and by a second hot roll 22 heated to a temperature of 130°C
at a speed of 710 m/min, so that drawing at a draw ratio of 4.1 and the heat setting
were performed. Further, the drawn yarn was taken over by a cold godet roll 23 at
a speed of 710 m/min, and then wound while the spindle rotational speed was controlled
so as to obtain a drawn yarn package 24 of a polyester monofilament of 31.8 dtex (fiber
diameter 54 µm).
[0061] The obtained polyester monofilament had a breaking strength of 4.7 cN/dtex, a breaking
elongation of 44.5%, a 10% modulus of 3.0 cN/dtex, a titanium oxide amount of 0.025
wt%, and other physical properties are as shown in Table 1. When the obtained 31.8
dtex (54 µm) polyester monofilament was wound on a transparent acrylic plate for four
rounds (eight layers) and irradiated with a wavelength of 405 nm, the transmittance
was 39%.
[0062] Table 1 shows the evaluation results of the quality of the screen mesh cloth based
on fluffing and scum defects when the obtained polyester monofilament was woven with
a mesh number #120 and the printing evaluation results based on the line accuracy
and the dimensional stability when irradiated with 405 nm laser for 40 seconds. The
quality of the screen mesh cloth was very good as the fluffing and scum defects w
0 to 1 per 30 m in length. When the woven mesh fabric was irradiated with a wavelength
of 405 nm, the transmittance was 82%. As a result of the printing evaluation, the
line accuracy was extremely good, good results were obtained for dimensional stability,
and overall excellent printing accuracy was obtained.
(Example 2)
[0063] A polyester monofilament of 32.0 dtex was obtained in the same manner as in Example
1 except that the titanium oxide content was changed to 0.001 wt%.
[0064] The titanium oxide amount of the obtained polyester monofilament is 0.001 wt%, and
the other physical properties are as shown in Table 1. The transmittance when irradiated
with a wavelength of 405 nm was as high as 46%, which was higher than that of Example
1, because of the decrease in the titanium oxide content. On the other hand, since
the formation of fine unevenness on the fiber surface is prevented because of the
decrease in the titanium oxide content, the dynamic friction coefficient between the
raw yarn and the satin metal was slightly higher than that in Example 1. As for the
screen mesh cloth quality, the fluffing and scum defects were the same as those in
Example 1, and the results were extremely good. When the woven mesh fabric was irradiated
with a wavelength of 405 nm, the transmittance was 86%. As the printing evaluation
results, the line accuracy and the dimensional stability were the same as those in
Example 1, and excellent printing accuracy was obtained.
(Comparative Example 1)
[0065] A polyester monofilament of 32.5 dtex was obtained in the same manner as in Example
1 except that the transmittance when irradiated with a wavelength of 405 nm was set
to 18% by changing the titanium oxide content to 0.500 wt%.
[0066] The titanium oxide amount of the obtained polyester monofilament is 0.500 wt%, and
the other properties are as shown in Table 1. Since the titanium oxide content was
increased, the dynamic friction coefficient between the raw yarn and the satin metal
was lower than that in Example 1, but the transmittance when irradiated with a wavelength
of 405 nm was significantly reduced to 18%. As for the screen mesh cloth quality,
the result was extremely good as in Example 1. On the other hand, the transmittance
when the woven mesh fabric was irradiated with a wavelength of 405 nm was 68%. As
the printing evaluation results, since the time for emulsion curing was insufficient,
unevenness occurred at the line boundary, and the printing accuracy was significantly
inferior to that in Example 1 from the viewpoint of line accuracy.
(Example 3)
[0067] A polyester monofilament of 32.4 dtex was obtained in the same manner as in Example
1 except that the intrinsic viscosity was changed.
[0068] The obtained polyester monofilament had an intrinsic viscosity of 0.77, a breaking
strength of 5.5 cN/dtex, a breaking elongation of 32.4%, and a 10% modulus of 3.9
cN/dtex. The other physical properties were as shown in Table 1, by increasing the
IV as compared with Example 1, the stress applied to the yarn during spinning and
drawing was increased, and a yarn with the high strength, low elongation, and high
modulus was obtained. As for the screen mesh cloth quality, the result was extremely
good as in Example 1. As the printing evaluation results, the line accuracy was extremely
good, and because of the high strength and low elongation, the dimensional stability
was improved as compared with Example 1, and the printing accuracy was extremely good.
[0069] Results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.
Table 1
|
Example 1 |
Example 2 |
Comparative Example 1 |
Example 3 |
Kind of Polyester |
PET |
PET |
PET |
PET |
Yarn production Process |
Two-step Method |
Two-step Method |
Two-step Method |
Two-step Method |
Drawing Method |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
Cross-sectional Form of Yarn |
Single Component |
Single Component |
Single Component |
Single Component |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
54 |
54 |
Content of Modified silicone product |
wt% |
7 |
7 |
7 |
7 |
Emulsion Concentration |
wt% |
4 |
4 |
4 |
4 |
Spinning Godet Roll |
Speed |
m/min |
900 |
900 |
900 |
900 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
91 |
91 |
Speed |
m/min |
174 |
174 |
174 |
174 |
Second hot roll |
Temperature |
°C |
130 |
130 |
130 |
130 |
Speed |
m/min |
710 |
710 |
710 |
710 |
Drawing Cold Godet Roll |
Speed |
m/min |
710 |
710 |
710 |
710 |
Draw ratio |
Times |
4.1 |
4.1 |
4.1 |
4.1 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.001 |
0.500 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.64 |
0.64 |
0.63 |
0.77 |
Single Fiber Fineness |
dtex |
31.8 |
32.0 |
32.5 |
32.4 |
Breaking Strength |
cN/dtex |
4.7 |
4.8 |
4.7 |
5.5 |
Breaking Elongation |
% |
44.5 |
43.6 |
44.9 |
32.4 |
10% Modulus |
cN/dtex |
3.0 |
3.1 |
2.9 |
3.9 |
Boiling Water Shrinkage Rate |
% |
6.7 |
6.8 |
6.5 |
8.8 |
Dynamic Friction Coefficient between Raw yarn and Satin Metal |
- |
0.159 |
0.168 |
0.141 |
0.148 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.13 |
0.14 |
0.15 |
0.16 |
Uster Unevenness U% (N) |
% |
0.99 |
1.15 |
0.97 |
1.01 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
39 |
46 |
18 |
35 |
Screen mesh cloth |
Platemaking/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#120 |
#120 |
#120 |
#120 |
Transmittance when Woven Mesh Fabric was irradiated with Wavelength of 405 nm |
% |
82 |
86 |
68 |
- |
Screen mesh cloth Quality |
|
A |
A |
A |
A |
Printing Accuracy |
|
B |
B |
D |
A |
(Example 4)
[0070] A polyester monofilament of 31.1 dtex was obtained in the same manner as in Example
1 except that the intrinsic viscosity was changed.
[0071] The obtained polyester monofilament had an intrinsic viscosity of 0.92, a breaking
strength of 6.3 cN/dtex, a breaking elongation of 21.3%, and a 10% modulus of 5.1
cN/dtex. The other physical properties were as shown in Table 2, and as in Example
3, a yarn with a high strength, a low elongation, and a high modulus was obtained
by increasing IV as compared with Example 1. As for the screen mesh cloth quality,
the result was extremely good as in Example 1. As the printing evaluation results,
because of the increase in intrinsic viscosity, the shear stress at the spinneret
increased, resulting in the Uster unevenness U% (N) being slightly worse than in Example
1 and resulting in inferior fiber diameter uniformity, the line accuracy was slightly
inferior to that in Example 1. On the other hand, because of the high strength and
low elongation, dimensional stability was improved as compared with Example 1, and
the overall printing accuracy was the same as that in Example 1.
(Comparative Example 2)
[0072] A polyester monofilament of 33.0 dtex was obtained in the same manner as in Example
1 except that the intrinsic viscosity was changed.
[0073] The obtained polyester monofilament had an intrinsic viscosity of 0.55, a breaking
strength of 4.2 cN/dtex, a breaking elongation of 52.4%, and a 10% modulus of 2.3
cN/dtex. The other physical properties were as shown in Table 2, and a yarn having
a low strength, a high elongation, and a low modulus was obtained by lowering the
IV as compared with Example 1. As for the screen mesh cloth quality, the result was
extremely good as in Example 1. As the print evaluation results, since the modulus
was lower than that in Example 1, the cloth tensioning stability was lowered, and
the line accuracy was lowered as compared with Example 1. The dimensional stability
was also greatly lowered from the occurrence of the cloth elongation due to the low
strength and high elongation, and the printing accuracy was significantly inferior
to that in Example 1.
(Example 5)
[0074] A polyester monofilament of 33.0 dtex was obtained in the same manner as in Example
1 except that the spinning speed (the speed of the spinning godet roll) was changed.
[0075] The obtained polyester monofilament had a breaking strength of 6.0 cN/dtex, a breaking
elongation of 26.5%, a 10% modulus of 4.7 cN/dtex, and other physical properties as
shown in Table 2. In the case where the spinning speed was high, the orientation of
the fiber surface was increased, fluffing defects and scum defects in the weaving
process were slightly increased as compared with Example 1, and the screen mesh cloth
quality was slightly inferior to that in Example 1, but not problematic in practical
use. As the printing evaluation results, the line accuracy was extremely good, and
because of the high strength and low elongation, the dimensional stability was improved
as compared with Example 1, and the printing accuracy was extremely good.
(Example 6)
[0076] A polyester monofilament of 32.7 dtex was obtained in the same manner as in Example
1 except that the content of the fatty acid alkyl ester in the oil agent was changed.
[0077] The physical properties of the obtained polyester monofilament were as shown in Table
2, and the dynamic friction coefficient between the raw yarn and the satin metal was
0.190, which was higher than that in Example 1. Because of the higher friction than
in Example 1, fluffing defects and scum defects were slightly increased in the weaving
process, and the screen mesh cloth quality was slightly inferior to that in Example
1, but not problematic in practical use. As the printing evaluation results, both
the line accuracy and the dimensional stability were the same as those in Example
1, and excellent printing accuracy was obtained.
[0078] The results of Examples 4 to 6 and Comparative Example 2 are shown in Table 2.
Table 2
|
Example 4 |
Comparative Example 2 |
Example 5 |
Example 6 |
Kind of Polyester |
PET |
PET |
PET |
PET |
Yarn production Process |
Two-step Method |
Two-step Method |
Two-step Method |
Two-step Method |
Drawing Method |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
Cross-sectional Form of Yarn |
Single Component |
Single Component |
Single Component |
Single Component |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
54 |
43 |
Content of Modified silicone product |
wt% |
7 |
7 |
7 |
7 |
Emulsion Concentration |
wt% |
4 |
4 |
4 |
4 |
Spinning Godet Roll |
Speed |
m/min |
900 |
900 |
1320 |
900 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
91 |
91 |
Speed |
m/min |
174 |
174 |
174 |
174 |
Second hot roll |
Temperature |
°C |
130 |
130 |
130 |
130 |
Speed |
m/min |
710 |
710 |
710 |
710 |
Drawing Cold Godet Roll |
Speed |
m/min |
710 |
710 |
710 |
710 |
Draw ratio |
Times |
4.1 |
4.1 |
4.1 |
4.1 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.025 |
0.025 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.92 |
0.55 |
0.64 |
0.64 |
Single Fiber Fineness |
dtex |
31.1 |
33.0 |
33.0 |
32.7 |
Breaking Strength |
cN/dtex |
6.3 |
4.2 |
6.0 |
4.7 |
Breaking Elongation |
% |
21.3 |
52.4 |
26.5 |
44.3 |
10% Modulus |
cN/dtex |
5.1 |
2.3 |
4.7 |
3.0 |
Boiling Water Shrinkage Rate |
% |
11.1 |
6.1 |
9.6 |
6.6 |
Dynamic Friction Coefficient between Raw Yarn and Satin Metal |
- |
0.161 |
0.155 |
0.159 |
0.190 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.15 |
0.12 |
0.15 |
0.15 |
Uster Unevenness U% (N) |
% |
1.45 |
1.17 |
1.00 |
0.97 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
35 |
37 |
37 |
37 |
Screen mesh cloth |
Plate making/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#120 |
#120 |
#120 |
#120 |
Screen mesh cloth Quality |
|
A |
A |
B |
B |
Printing Accuracy |
|
B |
D |
A |
B |
(Example 7)
[0079] A polyester monofilament of 32.1 dtex was obtained in the same manner as in Example
1 except that the content of the modified silicone product in the oil agent was changed
to 2 wt%.
[0080] The physical properties of the obtained polyester monofilament were as shown in Table
3, and the dynamic friction coefficient between the raw yarn and the satin metal was
0.203, which was higher than that of Example 1. Because of the higher friction than
in Example 1, fluffing defects and scum defects were slightly increased in the weaving
process, and the screen mesh cloth quality was slightly inferior to that in Example
1, but not problematic in practical use. As the printing evaluation results, the line
accuracy was slightly inferior to that in Example 1 since partial fluffing and printing
defects occurred. The dimensional stability was good as in Example 1, and the overall
printing accuracy was slightly inferior to that in Example 1, but generally excellent
printing accuracy was obtained.
(Example 8)
[0081] A polyester monofilament of 33.0 dtex was obtained in the same manner as in Example
1 except that the content of the modified silicone product in the oil agent was changed
to 5 wt%.
[0082] The physical properties of the obtained polyester monofilament were as shown in Table
3, and the dynamic friction coefficient between the raw yarn and the satin metal was
0.184, which was higher than that of Example 1. Because of the higher friction than
in Example 1, fluffing defects and scum defects were slightly increased in the weaving
process, and the screen mesh cloth quality was slightly inferior to that in Example
1, but not problematic in practical use. As the printing evaluation results, both
the line accuracy and the dimensional stability were the same as those in Example
1, and excellent printing accuracy was obtained.
(Example 9)
[0083] A polyester monofilament of 33.1 dtex was obtained in the same manner as in Example
1 except that the content of the modified silicone product in the oil agent was changed
to 9 wt%.
[0084] The physical properties of the obtained polyester monofilament were as shown in Table
3, and the dynamic friction coefficient between the raw yarn and the satin metal was
0.160, which was equivalent to that in Example 1. However, the oil film cracking on
the oil feed roll occurred in the yarn production process. As a result, non-uniform
adhesion of oil to the yarn was considered to have occurred, and fluffing defects
and scum defects increased slightly during the weaving process, and the screen mesh
cloth quality was slightly inferior to that in Example 1, but not problematic in practical
use. As the printing evaluation results, both the line accuracy and the dimensional
stability were the same as those in Example 1, and excellent printing accuracy was
obtained.
(Example 10)
[0085] A polyester monofilament of 32.9 dtex was obtained in the same manner as in Example
1 except that the oil adhesion amount of the drawn yarn was changed to 0.35 wt%. The
physical properties of the obtained polyester monofilament were as shown in Table
3. As for the screen mesh cloth quality, the fluffing and scum defects were the same
as those in Example 1, and the result was extremely good. As the printing evaluation
results, the line accuracy and the dimensional stability were the same as those in
Example 1, and excellent printing accuracy was obtained.
[0086] The results of Examples 7 to 10 are shown in Table 3.
Table 3
|
Example 7 |
Example 8 |
Example 9 |
Example 10 |
Kind of Polyester |
PET |
PET |
PET |
PET |
Yarn production Process |
Two-step Method |
Two-step Method |
Two-step Method |
Two-step Method |
Drawing Method |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
Cross-sectional Form of Yarn |
Single Component |
Single Component |
Single Component |
Single Component |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
54 |
54 |
Content of Modified silicone product |
wt% |
2 |
5 |
9 |
7 |
Emulsion Concentration |
wt% |
4 |
4 |
4 |
4 |
Spinning Godet Roll |
Speed |
m/min |
900 |
900 |
900 |
900 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
91 |
91 |
Speed |
m/min |
174 |
174 |
174 |
174 |
Second hot roll |
Temperature |
°C |
130 |
130 |
130 |
130 |
Speed |
m/min |
710 |
710 |
710 |
710 |
Drawing Cold Godet Roll |
Speed |
m/min |
710 |
710 |
710 |
710 |
Draw ratio |
Times |
4.1 |
4.1 |
4.1 |
4.1 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.025 |
0.025 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.64 |
0.64 |
0.64 |
0.64 |
Single Fiber Fineness |
dtex |
32.1 |
33.0 |
33.1 |
32.9 |
Breaking Strength |
cN/dtex |
4.6 |
4.6 |
4.7 |
4.8 |
Breaking Elongation |
% |
44.8 |
45.2 |
44.8 |
43.2 |
10% Modulus |
cN/dtex |
3.0 |
2.9 |
3.0 |
3.1 |
Boiling Water Shrinkage Rate |
% |
6.5 |
6.3 |
6.4 |
6.9 |
Dynamic Friction Coefficient between Raw Yarn and Satin Metal |
- |
0.203 |
0.184 |
0.160 |
0.145 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.14 |
0.14 |
0.13 |
0.35 |
Uster Unevenness U% (N) |
% |
0.99 |
0.99 |
0.96 |
1.04 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
38 |
38 |
35 |
37 |
Screen mesh cloth |
Platemaking/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#120 |
#120 |
#120 |
#120 |
Screen mesh cloth Quality |
|
B |
B |
B |
A |
Printing Accuracy |
|
C |
B |
B |
B |
(Example 11)
[0087] A polyester monofilament of 33.1 dtex was obtained in the same manner as in Example
1 except that the oil adhesion amount of the drawn yarn was changed to 0.07 wt%.
[0088] The physical properties of the obtained polyester monofilament were as shown in Table
4, and the dynamic friction coefficient between the raw yarn and the satin metal was
0.191, which was higher than that in Example 1. Because of the higher friction than
in Example 1, fluffing defects and scum defects were slightly increased in the weaving
process, and the screen mesh cloth quality was slightly inferior to that in Example
1, but not problematic in practical use. As the printing evaluation results, the line
accuracy was slightly inferior to that in Example 1 since partial fluffing and printing
defects occurred. The dimensional stability was good as in Example 1, and the overall
printing accuracy was slightly inferior to that in Example 1, but generally excellent
printing accuracy was obtained.
(Example 12)
[0089] A polyester monofilament of 32.1 dtex was obtained in the same manner as in Example
1 except that the oil adhesion amount of the drawn yarn was changed to 0.75 wt%.
[0090] The physical properties of the obtained polyester monofilament were as shown in Table
4, by increasing the oil adhesion amount of the drawn yarn as compared with Example
1, the oil was dropped in the weaving process and scum defects were generated, and
the screen mesh cloth quality was slightly inferior to that in Example 1, but not
problematic in practical use. As the printing evaluation results, the line accuracy
was slightly inferior to that in Example 1 since scum was partially mixed in the woven
fabric and printing defects were generated. The dimensional stability was good as
in Example 1, and the overall printing accuracy was slightly inferior to that in Example
1, but generally excellent printing accuracy was obtained.
(Example 13)
[0091] A polyester monofilament of 32.1 dtex was obtained in the same manner as in Example
1 except that the temperature of the first hot roll was changed in the drawing step.
[0092] The physical properties of the obtained polyester monofilament were as shown in Table
4. As for the screen mesh cloth quality, the result was extremely good as in Example
1. As the printing evaluation results, since the preheating for drawing was insufficient,
the Uster unevenness U% (N) was slightly worse as compared with Example 1, resulting
in inferior fiber diameter uniformity, so that the line accuracy was slightly inferior
to that in Example 1. The dimensional stability was as good as in Example 1, and the
overall printing accuracy was slightly inferior to that in Example 1, but generally
excellent printing accuracy was obtained.
(Example 14)
[0093] A polyester monofilament of 31.8 dtex was obtained in the same manner as in Example
1 except that the speed of the first hot roll was changed and the draw ratio was changed
to 4.7 times in the drawing process.
[0094] The obtained polyester monofilament had a breaking strength of 5.5 cN/dtex, a breaking
elongation of 30.0%, a 10% modulus of 4.3 cN/dtex, and other physical properties as
shown in Table 4. Compared to Example 1, the fiber surface orientation was increased
due to a high draw ratio, and the number of fluffing defects and the number of scum
defects were slightly increased in the weaving process. As a result, the screen mesh
cloth quality was slightly inferior to that in Example 1, but not problematic in practical
use. As the printing evaluation results, the line accuracy and the dimensional stability
were the same as those in Example 1, and excellent printing accuracy was obtained.
[0095] The results of Examples 11 to 14 are shown in Table 4.
Table 4
|
Example 11 |
Example 12 |
Example 13 |
Example 14 |
Kind of Polyester |
PET |
PET |
PET |
PET |
Yarn production Process |
Two-step Method |
Two-step Method |
Two-step Method |
Two-step Method |
Drawing Method |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
One-stage Drawing |
Cross-sectional Form of Yarn |
Single Component |
Single Component |
Single Component |
Single Component |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
54 |
54 |
Content of Modified silicone product |
wt% |
7 |
7 |
7 |
7 |
Emulsion Concentration |
wt% |
4 |
4 |
4 |
4 |
Spinning Godet Roll |
Speed |
m/min |
900 |
900 |
900 |
900 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
75 |
91 |
Speed |
m/min |
174 |
174 |
174 |
150 |
Second hot roll |
Temperature |
°C |
130 |
130 |
130 |
130 |
Speed |
m/min |
710 |
710 |
710 |
710 |
Drawing Cold Godet Roll |
Speed |
m/min |
710 |
710 |
710 |
710 |
Draw ratio |
Times |
4.1 |
4.1 |
4.1 |
4.7 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.025 |
0.025 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.64 |
0.64 |
0.64 |
0.64 |
Single Fiber Fineness |
dtex |
33.1 |
32.1 |
32.1 |
31.8 |
Breaking Strength |
cN/dtex |
4.7 |
4.7 |
4.7 |
5.5 |
Breaking Elongation |
% |
46.1 |
44.1 |
44.0 |
30.0 |
10% Modulus |
cN/dtex |
2.9 |
3.0 |
3.0 |
4.3 |
Boiling Water Shrinkage Rate |
% |
6.5 |
6.3 |
6.7 |
8.7 |
Dynamic Friction Coefficient between Raw Yarn and Satin Metal |
- |
0.191 |
0.152 |
0.164 |
0.159 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.07 |
0.75 |
0.15 |
0.13 |
Uster Unevenness U% (N) |
% |
1.31 |
1.00 |
1.71 |
0.93 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
36 |
40 |
35 |
39 |
Screen mesh cloth |
Platemaking/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#120 |
#120 |
#120 |
#120 |
Screen mesh cloth Quality |
|
B |
B |
A |
B |
Printing Accuracy |
|
C |
C |
C |
B |
(Example 15)
[0096] A polyester monofilament of 20.0 dtex (fiber diameter of 43 µm) was obtained in the
same manner as in Example 1 except that the draw ratio was changed to 4.3 times by
changing the first hot roll speed and the target fineness was changed by changing
the discharge amount.
[0097] The obtained polyester monofilament had a breaking strength of 5.6 cN/dtex, a breaking
elongation of 32.5%, a 10% modulus of 4.1 cN/dtex, and other physical properties as
shown in Table 5. The polyester monofilament of 20.0 dtex (43 µm) was wound around
a transparent acrylic plate for five rounds (10 layers) so as to have a density equivalent
to that of a plate-wound sample obtained by winding a filament of 32 dtex (54 µm)
for four rounds (8 layers), and the transmittance when irradiated with a wavelength
of 405 nm was 37%.
[0098] In order to make the strength of the screen mesh cloth equal to that in Example 1,
the obtained polyester monofilament was woven with a mesh number #220, and the cloth
quality and the printing accuracy were evaluated. As for the screen mesh cloth quality,
the result was extremely good as in Example 1. As the printing evaluation results,
the line accuracy was extremely good, and in addition, the dimensional stability was
improved due to the high strength and high modulus as compared with Example 1, and
the printing accuracy was extremely good.
(Example 16)
[0099] A polyester monofilament of 8.0 dtex (fiber diameter of 27 µm) was obtained in the
same manner as in Example 1 except that the draw ratio was changed to 4.3 times by
changing the first hot roll speed and the target fineness was changed by changing
the discharge amount.
[0100] The obtained polyester monofilament had a breaking strength of 5.4 cN/dtex, a breaking
elongation of 37.0%, a 10% modulus of 3.8 cN/dtex, and other physical properties as
shown in Table 5. A polyester monofilament of 8.0 dtex (27 µm) was wound around a
transparent acrylic plate for eight rounds (16 layers) so as to have a density equivalent
to that of a plate-wound sample obtained by winding a filament of 32 dtex (54 µm)
for four rounds (8 layers), and the transmittance when irradiated with a wavelength
of 405 nm was 38%.
[0101] In order to make the strength of the screen mesh cloth equal to that in Example 1,
the obtained polyester monofilament was woven with a mesh number #380, and the cloth
quality and the printing accuracy were evaluated. As for the screen mesh cloth quality,
the result was extremely good as in Example 1. As the printing evaluation results,
the line accuracy was extremely good, and in addition, the dimensional stability was
improved because of the high strength and high modulus as compared with Example 1,
and the printing accuracy was extremely good.
[0102] The results of Examples 15 to 16 are shown in Table 5.
Table 5
|
Example 15 |
Example 16 |
Kind of Polyester |
PET |
PET |
Yarn production Process |
Two-step Method |
Two-step Method |
Drawing Method |
One-stage Drawing |
One-stage Drawing |
Cross-sectional Form of Yarn |
Single Component |
Single Component |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
Content of Modified silicone product |
wt% |
7 |
7 |
Emulsion Concentration |
wt% |
4 |
4 |
Spinning Godet Roll |
Speed |
m/min |
900 |
900 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
Speed |
m/min |
165 |
165 |
Second hot roll |
Temperature |
°C |
130 |
130 |
Speed |
m/min |
710 |
710 |
Drawing Cold Godet Roll |
Speed |
m/min |
710 |
710 |
Draw ratio |
Times |
4.3 |
4.3 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.72 |
0.71 |
Single Fiber Fineness |
dtex |
20.0 |
8.0 |
Breaking Strength |
cN/dtex |
5.6 |
5.4 |
Breaking Elongation |
% |
32.5 |
37.0 |
10% Modulus |
cN/dtex |
4.1 |
3.8 |
Boiling Water Shrinkage Rate |
% |
8.2 |
8.0 |
Dynamic Friction Coefficient between Raw yarn and Satin Metal |
- |
0.162 |
0.157 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.16 |
0.20 |
Uster Unevenness U% (N) |
% |
0.81 |
0.62 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
37 |
38 |
Screen mesh cloth |
Platemaking/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#220 |
#380 |
Screen mesh cloth Quality |
|
A |
A |
Printing Accuracy |
|
A |
A |
(Example 17)
[0103] A core-sheath composite polyester monofilament was produced by a one-step method
(direct spinning and drawing method) using a yarn production device equipped with
the equipment shown in FIG. 5. That is, polyethylene terephthalate (glass transition
temperature: 80°C) having a titanium oxide content of 0.025 wt% and an intrinsic viscosity
of 1.00 as a high-viscosity polymer, and polyethylene terephthalate (glass transition
temperature 80°C) having a titanium oxide content of 0.025 wt% and an intrinsic viscosity
of 0.51 as a low-viscosity polymer were polymerized by a common method to form a chip.
The obtained two kinds of polyethylene terephthalate were melted at a temperature
of 298°C using an extruder, weighed by a pump at a polymer temperature of 295°C, and
flowed into a common composite spinneret 25 so that the high-viscosity polymer was
arranged in the core component and the low-viscosity polymer was arranged in the sheath
component at a core-sheath ratio of 80:20. The pressure applied to the spinneret was
18 MPa for the core component, and the pipe passage time of the core component polymer
was 10 minutes. Thereafter, the polyester monofilament discharged from the composite
spinneret 25 was actively heated and maintained warm by a heat-insulating cylinder
26 at 380°C, and then was cooled by applying cool air at a speed of 10 m/min by a
yarn cooling blowing device 27. After applying an oil agent having an emulsion concentration
of 10 wt% by an oil feed roll 28, the yarn was taken up by an non-heated spinning
godet roll 29 at a speed of 500 m/min, and was, without being wound up once, taken
up by a first hot roll 30 heated to a temperature of 91 °C at a speed of 505 m/min,
a second hot roll 31 heated to a temperature of 91 °C at a speed of 2,092 m/min and
a third hot roll 32 heated to a temperature of 200°C at a speed of 2,929 m/min, so
that two-stage drawing at a draw ratio of 5.8 times and heat setting were performed.
Further, after taken up by the cold godet rolls 33, 34 at a speed of 2,929 m/min,
the drawn yarn was wound while the spindle rotational speed was controlled such that
the winding tension was 0.3 cN/dtex by a yarn winding device 35, thereby obtaining
a drawn yarn package 36 of a core-sheath composite polyester monofilament of 6.0 dtex
(fiber diameter of 24 µm). The oil agent applied to the polyester monofilament contains
54 wt% of a fatty acid alkyl ester and 7 wt% of silicone modified product as a smoothing
agent, an alkyl phosphate as an extreme pressure agent, an alkyl sulfonate as an antistatic
agent, a nonionic ester and a nonionic ether as an emulsifier.
[0104] The obtained polyester monofilament had a breaking strength of 8.5 cN/dtex, a breaking
elongation of 13.7%, a 10% modulus of 8.1 cN/dtex, a titanium oxide amount of 0.025
wt%, an intrinsic viscosity of 0.81, and other physical properties as shown in Table
6. When a polyester monofilament of 6.0 dtex (24 µm) was wound around a transparent
acrylic plate for nine rounds (18 layers) such that the density was equivalent to
that of a plate-wound sample in which a filament of 32 dtex (54 µm) was wound four
rounds (eight layers), and was irradiated with the wavelength of 405 nm, the transmittance
was 31%. It was considered that since the cross-sectional shape of the yarn was a
core-sheath composite, light rays with a wavelength of 405 nm were slightly reflected
and scattered at the interface between the core and the sheath, and the transmittance
was slightly lower than that in Example 1.
[0105] Table 6 shows the evaluation results of the screen mesh cloth quality due to fluffing
and scum defects when the obtained polyester monofilament was woven with a mesh number
#420 and the printing evaluation results based on the line accuracy and the dimensional
stability. As the screen mesh cloth quality, a low-viscosity polymer was arranged
in the sheath component, but due to the high modulus, the fluffing and scum defects
was 2 to 5 per 30 m in length, which was slightly inferior to that in Example 1, but
there was no problem in practical use. As the printing evaluation results, although
the transmittance of the yarn was slightly lower than that in Example 1, the line
accuracy was not affected and the cloth stability was improved, extremely good line
accuracy was obtained as in Example 1. With respect to dimensional stability, extremely
excellent dimensional stability was obtained due to the high strength and the low
elongation, and overall excellent printing accuracy was obtained as compared with
Example 1.
(Comparative Example 3)
[0106] Similarly to Example 17, a core-sheath composite polyester monofilament was produced
by a one-step method (direct spinning drawing method). At this time, the speed of
the spinning godet roll was changed to 475 m/min, the speed of the first hot roll
was changed to 480 m/min, and the draw ratio was changed to 6.2. In addition, the
temperature of the third hot roll was changed to 220°C, and the other manufacturing
conditions were similar to Example 17, a core-sheath composite polyester monofilament
of 6.0 dtex (fiber diameter of 24 µm) was obtained.
[0107] The physical properties of the polyester monofilament obtained were as follows: a
breaking strength of 9.2 cN/dtex, a breaking elongation of 10.2%, a 10% modulus of
9.1 cN/dtex, a boiling water shrinkage rate of 4.8%, and a titanium oxide content
of 0.025 wt%, and the other physical properties were as shown in Table 6. When a polyester
monofilament of 6.0 dtex (24 µm) was wound around a transparent acrylic plate for
nine rounds (18 layers) such that the density was equivalent to that of a plate-wound
sample in which a filament of 32 dtex (54 µm) was wound four rounds (eight layers),
and was irradiated with the wavelength of 405 nm, the transmittance was 26%. In addition
to the reflection and scattering of light rays of 405 nm due to a core-sheath composite
cross section, the yarn was slightly whitened because of the proceeding of excessive
crystallization. As a result, the transmittance was inferior to that in Example 1.
[0108] Table 6 shows the evaluation results of the screen mesh cloth quality based on fluffing
and scum defects when the obtained polyester monofilament was woven with a mesh number
#420 and the printing evaluation results based on the line accuracy and the dimensional
stability. In the weaving process, the drawing margin of the cloth was reduced by
decreasing the low elongation, and the yarn breakage was increased. As for the screen
mesh cloth quality, the number of fluffing and scum defects were 6 to 9 per 30 m in
length because of the higher draw ratio and the higher modulus as compared with Example
17. The result was significantly inferior to that in Example 1. As the printing evaluation
results, since the transmittance of the yarn was lower than that in Example 1, the
emulsion curing was more or less insufficient, though it was better than Comparative
Example 1, and the line boundary was uneven, so that the printing accuracy was far
inferior to Example 1 from the viewpoint of line accuracy.
[0109] The results of Example 17 and Comparative Example 3 are shown in Table 6.
[Table 6]
|
Example 17 |
Comparative Example 3 |
Kind of Polyester |
PET |
PET |
Yarn production Process |
One-step Method |
One-step Method |
Drawing Method |
Two-stage Drawing |
Two-stage Drawing |
Cross-sectional Form of Yarn |
Core-sheath Composite |
Core-sheath Composite |
Oil Emulsion |
Content of Fatty Acid Alkyl Ester |
wt% |
54 |
54 |
Content of Modified silicone product |
wt% |
7 |
7 |
Emulsion Concentration |
wt% |
10 |
10 |
Spinning Godet Roll |
Speed |
m/min |
500 |
475 |
First Hot Roll |
Temperature |
°C |
91 |
91 |
Speed |
m/min |
505 |
480 |
Second hot roll |
Temperature |
°C |
91 |
91 |
Speed |
m/min |
2092 |
2092 |
Third hot roll |
Temperature |
°C |
200 |
220 |
Speed |
m/min |
2929 |
2929 |
Drawing Cold Godet Roll |
Speed |
m/min |
2929 |
2929 |
Draw ratio |
Times |
5.8 |
6.2 |
Titanium Oxide Content of Yarn |
wt% |
0.025 |
0.025 |
Intrinsic Viscosity of Yarn |
- |
0.81 |
0.81 |
Single Fiber Fineness |
dtex |
6.0 |
6.0 |
Breaking Strength |
cN/dtex |
8.5 |
9.2 |
Breaking Elongation |
% |
13.7 |
10.2 |
10% Modulus |
cN/dtex |
8.1 |
9.1 |
Boiling Water Shrinkage Rate |
% |
6.2 |
4.8 |
Dynamic Friction Coefficient between Raw yarn and Satin Metal |
- |
0.166 |
0.166 |
Oil Adhesion Amount of Drawn Yarn |
wt% |
0.48 |
0.48 |
Uster Unevenness U% (N) |
% |
0.74 |
0.77 |
Transmittance when Monofilament was irradiated with Wavelength of 405 nm |
% |
31 |
26 |
Screen mesh cloth |
Platemaking/Printing Method |
|
Direct Digital Platemaking |
Direct Digital Platemaking |
Mesh Number |
|
#420 |
#120 |
Screen mesh cloth Quality |
|
B |
C |
Printing Accuracy |
|
A |
D |
[0110] Although the present invention has been described in detail with reference to specific
embodiments, it will be apparent to those skilled in the art that various changes
and modifications can be made without departing from the spirit and scope of the present
invention. This application is based on
Japanese Patent Application No. 2018-182614 filed on September 27, 2018, the contents of which are incorporated herein by reference.
REFERENCE SIGNS LIST
[0111]
Y: Monofilament
d: Diameter of satin metal roll
1: Transparent acrylic plate
2: Aligned winding evaluation device
3: Unwinding guide
4: Nip roll
5: Tensor
6: Direction change roll
7: Yarn path regulation guide
8: Plate-wound sample
9: Balancer
10: Direction change guide
11: Fixing pin made of satin metal
12: Direction change guide
13: Tension meter
14: Take-up roll
15: Spinneret
16: Yarn cooling air blowing device
17: Oil feed roll
18: Godet roll
19: Undrawn yarn package
20: Feed roll
21: First hot roll
22: Second hot roll
23: Cold godet roll
24: Drawn yarn package 25: Composite spinneret
26: Heat-insulating cylinder
27: Yarn cooling air blowing device
28: Oil feed roll
29: Spinning godet roll
30: First hot roll
31: Second hot roll
32: Third hot roll
33: Cold godet roll
34: Cold godet roll
35: Yarn winding device
36: Drawn yarn package