BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to an animal fiber to which shrink proofing and pilling
resistance are given, and a method for preparation thereof. More specifically, the
present invention relates to an animal fiber to which shrink proofing and pilling
resistance are given without impairing a superior water repellent property that animal
fibers originally possess and a method for preparation thereof.
2. Description of the Prior Art
[0002] Animal fiber is peculiar natural fiber having specific hand-feeling texture depending
on sheep breeds, revealing bio-degradability, having various excellent properties
such as hygroscopicity, moisture-releasing property, heat retaining property, flame
retardancy and dyeing property, and further, water-repellency. It is special fiber
which has appropriate fiber strength and elongation permissible for wear and higher
abrasion resistance, also from the standpoint of fiber mechanical properties, and
has been esteemed for long time. However, felting property in aqueous washing and
pilling property in wear derived from a cuticle tissue structure of animal fiber are
undesirable natures as apparel wear. Therefore, studies for improving the surface
have been long effected mainly on shrink proofing, and pilling resistant work has
also been conducted along with the studies. However, any of animal fiber obtained
like this is an improving method sacrificing the water repellency which is an inherent
nature of animal fiber. A water repellent membrane of animal fiber is an organization
for exerting an influence on hygroscopicity and moisture releasing property and for
controlling heat transfer accompanied by adsorption and desorption of water, and exerts
an influence on heat retaining property and comfortability. In other words, the conventional
shrink proofing product can prevent shrink by aqueous washing, but lacks in heat retaining
property and comfortability.
[0003] As a conventional typical shrink proofing work, there is a shrink proofing method
using a chlorine agent, and specifically, what is called chlorine-Hercosett shrink
proofing method in which a cuticle tissue of animal fiber is hydrophilizated, the
tissue is made soft or removed to impart shrink proofing property, and further, the
cuticle tissue is coated with a polyamide epichlorohydrin resin (Hercosett resin,
manufactured by Dick Herculess) for enhancing the resistance to aqueous washing. Currently,
this method is spread around the world, and recognized provisionally as a complete
method as a shrink proofing method of wool.
[0004] However, from the stand point of environmental conservation spread currently around
the world, a shrink proofing work using a chlorine agent and chlorine-containing resin
has caused a problem of the discharging amount of an Adsorbable Organic Halides (AOX),
and a novel shrink proofing method of animal fiber using no chlorine agent is being
studied presently. However, a satisfactory method replacing the chlorine-Hercosett
shrink proofing method has not been developed yet.
[0005] Japanese Patent Kokai No. 126997/1975 discloses a method in which dyeing property
and shrink proofing of wool and pilling resistance of a wool-synthetic fiber blended
product are improved without deteriorating hand-feeling and fiber strength of wool
according to a procedure in which wool sliver is impregnated with an aqueous solution
of acids or acidic salts and drained by squeezing rolls, and is placed in a sealed
chamber previously filled with an ozone-containing gas having an ozone concentration
of 35.5 mL/L, and further, treated at 50°C for 10 minutes while feeding a new ozone-containing
gas. However, this method carries out only oxidation into a cystine crosslinked bond
(-S-S-) which performs main role of wool shrink proofing, and no reduction treatment
is conducted. In the case of wool, a -S-S-bond is not cleaved until this reduction
treatment and this cleavage gives satisfactory shrink proofing to wool, therefore,
sufficient shrink proofing and pilling resistance can not be obtained by the disclosed
method. Further, the above-mentioned methods is conducted in a sealed system since
the treatment should be conducted in an ozone gas atmosphere, and exposure is effected
with the aid of molecular movement of an ozone gas, therefore, when the amount of
wool treating is increased, unevenness of an ozone gas exposure can not be avoided,
and this directly produces a unevenness treatment and uniform wool shrink proofing
and dyeing are not obtained. At the same time, in the above-mentioned method, the
productivity is low due to the sealed system treatment, and when an ozone gas leaks
directly out of the treating apparatus, deterioration in working environment and environmental
charge are large, and industrialization is difficult.
[0006] Japanese Patent Kokai No. 142759/1980 discloses a method and an apparatus in which
fiber is treated with an ozone-steam mixed material. In this method, worsted knitted
fabric made of keratinous animal fiber is suspended on a belt conveyor circulating
in a special treatment apparatus equipped with an exhaust apparatus, steam is introduced
in this apparatus to increase the temperature to 79°C, a fan is started to introduce
an ozone-air mixed gas (ozone introduction amount: 3.4 g/minute) and this mixed gas
retained in the apparatus for 8.25 minutes to impart shrink proofing. Also in this
method, only ozone oxidation is conducted, and no reduction treatment is effected.
Therefore, the imparted shrink proofing is not satisfactory, and further, an ozone
gas tends to leak due to the defective construction of apparatus, inviting deterioration
in working environment.
[0007] Japanese Patent Kokai No. 19961/1991 discloses a method of shrink proofing of animal
fiber using ozone as an oxidizer. It describes that an ozone gas is passed through
a glass filter to give fine bubbles, in a water bath, and this bubbles are allowed
to contact animal fiber. But bubbles generated through a glass filter or the like
are too large to render ozone gas bubbles to reach fine portions in a fiber assembly,
and treat only the surface of the fiber assembly. It is well known from experience
that when a wool product containing about 90% of shrink-proofed wool fiber and about
10% of un-shrink-proofed wool fiber in mixture is washed in water, it is shrunk in
the same extent as a un-shrink-proofed wool product, whereas, in the above-mentioned
method, an unevenness exposure on wool by an ozone gas makes a unevenness treatment,
and sufficient shrink proofing is not obtained due to this unevenness.
[0008] Japanese Patent Kokai No. 72762/1998 discloses a method in which fiber is immersed
in the form of tow, thread, fabric, knit fabric and the like into a water-dissolved
ozone prepared by dispersing in water an ozone-containing gas composed of ozone and
oxygen or air in the form of bubbles having a diameter of 0.08 mm or less. It describes
a method in which an ozone-containing gas is introduced in water to form bubbles,
this bubbles are broken by allowing it to collide against small walls in a line mixer
when it passes through the line mixer, to give fine bubbles having a diameter of 0.08
mm or less showing enhanced solubility in water, for obtaining ozone dissolved in
water having high concentration. This is merely a method for treating rayon and other
fiber using ozone in dissolved in water.
SUMMARY OF THE INVENTION
[0009] The present invention provides an animal fiber to which high shrink proofing and
pilling resistance are simultaneously given without impairing its water repellence.
Moreover, the present invention also provides a method for preparation of the animal
fiber in which a chemical not containing toxic chlorine is used from the view point
of environmental preservation.
[0010] The present invention relates to an animal fiber which is superior in shrink proofing
and pilling resistance, and maintains a water repellent property that animal fibers
originally possess.
[0011] Specifically, the present invention relates to the animal fiber wherein the shrink
proofing is set to an area shrinkage rate of not more than 8 % in a three-hours aqueous
washing, when measured as a felting shrinkage rate in conformity with a WM TM 31 method
(Wool Mark Test Method 31).
[0012] More specifically, the present invention relates to the animal fiber which, with
respect to a value represented by a difference (µ
a - µ
w) between the coefficient of friction in the tip to root direction (µ
a) and the coefficient of friction in the root to tip direction (µ
w) with respect to a fiber direction, measured in accordance with JIS L-1015 method,
has a reduction of not less than 30 % in comparison with the difference (µ
a - µ
w) of untreated animal fiber in coefficient of static friction or in coefficient of
dynamic friction, with the value of µ
a being approximately the same as a value in the case of the untreated animal fiber
and the value of µ
w having an increase of not less than 30 % in comparison with a value in the case of
the untreated animal fiber.
[0013] The present invention also relates to the animal fiber in which the pilling resistance
is not lower than third class in JIS L-1076.6.1A method.
[0014] More specifically, the present invention relates to the animal fiber wherein, supposing
that an absorbance of an absorption band corresponding to amide I is set to 1 in a
reflection FT-IR measuring method, the degree of oxidation of a -S-S- bond (cystine
bond) in a epidermal cell of the animal fiber is represented by a relative absorbance
of not less than 0.1 in an absorption band of -SO
3H group (sulfonic acid group) and/or a relative absorbance of not less than 0.08 in
an absorption band of -S-SO
3Na group (Bunte salts).
[0015] The animal fiber of the present invention is obtainable by a method comprising:
a) a first step in which a -S-S- bond (cystine bond) in the cuticle cell of an animal
fiber is treated by primary oxidation into lower order oxidized state,
b) a second step in which the primary-oxidized -S-S-bond is treated by oxidation into
any one or more higher order oxidized states of di, tri or tetra-oxidized state, and
c) a third step in which said -S-S- bond in di, tri or tetra-oxidized state is treated
by reduction fission.
[0016] More specifically, the method comprises: a
a) a first step in which a -S-S- bond in the cuticle cell of an animal fiber is treated
by primary oxidation with an oxidizer having an ability to oxidize a cystine -S-S-bond
in animal fiber,
b) a second step in which the primary-oxidized -S-S-bond is treated by oxidation with
ozone into any one or more higher order oxidized states of di, tri or tetra-oxidized
state, and
c) a third step in which said -S-S- bond in higher oxidized state is treated by reduction
fission.
[0017] The present invention relates to animal fiber superior in shrink proofing and pilling
resistance properties obtained by any one of the methods described above.
[0018] Additionally, in the above description "supposing that an absorbance of an absorption
band corresponding to amide I is set to 1 in a reflection FT-IR measuring method,
the degree of oxidation of a -S-S- bond (cystine bond) is represented by a relative
absorbance of not less than 0.1 in an absorption band of -SO
3H group (sulfonic acid group) and/or a relative absorbance of not less than 0.08 in
an absorption band of -S-SO
3Na group (Bunte salts)", "the relative absorbance in an absorption band of -SO
3H group (sulfonic acid group)" more specifically refers to a relative absorbance of
the absorption band of 1040 cm
-1 corresponding to the -SO
3H group (sulfonic acid group) measured by the reflection FT-IR measuring method (ATR
method) in the case when the absorption band of 1650 cm
-1 corresponding to amide I is set to 1. Moreover, "the relative absorbance in an absorption
band of -S-SO
3Na group (Bunte salts)" refers to a relative absorbance of the absorption band of
1024 cm
-1 corresponding to the -S-SO
3Na group (Bunte salts) measured by the reflection FT-IR measuring method (ATR method)
in the case when the absorption band of 1650 cm
-1 corresponding to amide I is set to 1.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
Fig. 1 is a schematic longitudinal cross-sectional view that shows an animal fiber.
Fig. 2 are photographs of a scanning electronic microscope that show surfaces of untreated
wool fiber and various shrink proofing treated wool fiber.
(a) Untreated wool fiber,
(b) Chlorine-treated wool fiber,
(c) Chlorine-Hercosett-treated wool fiber
(d) Wool fiber of the present invention.
Fig. 3 is a side view that shows a processing device used for the method of the present
invention.
Fig. 4 is a drawing that explains an ozone treatment method.
Fig. 5 is a drawing that shows a state in which various wool fibers of Example 3 are
observed with respect to water repellency in a macroscopic manner.
Fig. 6 are optical microscopic photographs that show states of untreated wool fiber
and various shrink-proofing treated wool fiber under Allwörden reaction.
(a) Untreated wool fiber,
(b) Chlorine-treated wool fiber
(c) Chlorine-Hercosett-treated wool fiber
(d) Wool fiber of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The animal fiber of the present invention is characterized in that it has superior
shrink proofing and pilling resistance while maintaining a water repellent property
that animal fibers originally possess.
[0021] The shrink proofing of the animal fiber of the present invention is represented by
using the felting shrinkage rate or the difference in coefficient of friction in single
fiber as a measure.
[0022] When represented by the felting shrinkage rate, the shrink-proofing of the animal
fiber of the present invention is not more than 8 % in the area shrinkage rate in
a three-hours aqueous washing. More preferably, it is not more than 5 %.
[0023] In the case when represented by the coefficient of friction in single fiber, with
respect to a value represented by a difference (µ
a - µ
w) between the coefficient of friction in the tip to root direction (µ
a) and the coefficient of friction in the root to tip direction (µ
w) with respect to a fiber direction, it has a reduction of not less than 30 % in comparison
with that of untreated animal fiber in a static coefficient of friction or in a dynamic
coefficient of friction. More preferably, it has a reduction of not less than 40 %.
Moreover, the value of µ
a is approximately the same as a value in the case of the untreated animal fiber and
the value of µ
w has an increase of not less than 30 % in comparison with a value in the case of the
untreated animal fiber.
[0024] Here, in the present invention, the felting shrinkage rate is measured in conformity
with WM TM31 method (Wool Mark Test Method 31), and a fabric knitted into a cover-factor
C.F. 0.41 with one thread being taken from 14 gages is used as a sample. Here, "conformity
to "WM TM31 method" refers to the fact that the measurements were carried out in accordance
with the testing procedure of WM TM31 method set based upon the ISO 6330 method, while
the test washing machine was changed to a Cubex shrinkage testing machine.
[0025] In the present invention, the coefficient of friction of the single fiber is measured
in accordance with JIS L 1015, and the following conditions are used:
Test machine: Radar type test machine for coefficient of friction
Hanging line load: 200 mg
Cylinder peripheral velocity: 90 cm/min.
[0026] In this case, µ
a is a coefficient of friction in the tip to root direction with respect to a fiber
direction, and µ
w is a coefficient of friction in the root to tip direction with respect to a fiber
direction.
[0027] The pilling resistance of the animal fiber of the present invention is quantitatively
represented by a pilling test method in accordance with JIS L 1076.6. 1A, and it is
not lower than the third class in pilling resistance.
[0028] Based upon the above reference, the pilling test is carried out under the following
conditions:
Test machine: ICI-type pill box test machine
Knitted fabric: A fabric knitted by IP18G is used.
[0029] Water repellency is evaluated by putting a water droplet on a knitted fabric made
of animal fibers to be tested and observing the permeability of the water droplet
into the knitted fabric. The criteria of the evaluation are:
○: A water droplet stays on the fabric after a lapse of 30 minutes (equivalent to
natural animal fibers, etc.).
Δ: Virtually the whole of a water droplet permeates into the fabric after a lapse
of 2 to 30 minutes.
×: Virtually the whole of a water droplet permeates into the fabric in less than 2
minutes.
[0030] Here, the evaluation of water repellency may be made by putting a sample in the form
of sliver on the surface of water and measuring the time at which the sliver absorbs
water and sinks into water. In the animal fiber in accordance with the present invention,
a water droplet stays after a lapse of 30 minutes in the same manner as natural animal
fibers.
[0031] Moreover, the existence of a surface layer of epicuticle which adds a water repellent
property to the animal fiber may be confirmed by an Allwörden reaction (Wool Science
Review, Vol. 63 (1986)) in which animal fiber is dipped in a saturated chlorine water
solution or a saturated bromine water solution to find generation of bubbles on the
surface thereof.
[0032] The superior properties of the animal fiber of the present invention is achieved
by changing conformation of scale structure, and by exemplifying the surface structure
of wool, the mechanism of exertion of such superior shrink proofing and pilling resistance
that the inventors, etc., of the present invention have found is explained below.
[0033] Fig. 1 (quoted from Wool Science Review Vol. 63 (1986)) is a schematic longitudinal
cross-sectional view that shows the surface portion of a wool fiber. An epidermal
tissue (cuticle) portion, called scales, consists of an epicuticle layer (21), an
exocuticle A-layer (22), an exocuticle B-layer (23) and an endocuticle layer (24)
as an innermost layer that are stacked in this order from outside. Moreover, the outer
surface of the epicuticle layer is combined with a layer having a thickness of approximately
0.9 nm that is made from a higher fatty acid (mainly made of eicosanoic acid) which
is bonded to a -SH residue of a polypeptide chain in the epicuticle layer through
a thioester bond, and the alkyl group of this eicosanoic acid allows the animal fiber
to exert a superior water repellence property.
[0034] Further particularly, higher fatty acids possessing water repellency which constitutes
the outermost surface of the fiber, particularly, eicosanoic acid is connected with
an epicuticle layer (cystine content: 12%) via a thioester bond, and further, the
epicuticle layer and an exocuticle A layer (cystine content: 35%) adjacent to the
lower side of the epicuticle layer form an integrated structure, occupying about 20%
of the total thickness of the cuticle, and cystine bonds are distributed in this tissue
concentrically in an amount of about 70% based on the whole cystine content of the
cuticle. The remaining about 30% is known to be composed of an exocuticle B layer
(cystine content: 15%) and an endocuticle (cystine content: 3%).
[0035] Most of cuticle tissue is composed of an exocuticle A and B layers and endocuticle
layer, and the exocuticle A layer form an integrated tissue structure with epicuticle
layer, and the felting phenomenon depends, substantially, on the exocuticle B layer
and endocuticle layer.
[0036] When animal fiber is immersed in water, each layer absorbs water more or less and
swells. But, naturally, the more cystine crosslinkage develops, the less the extent
of swelling with water is. And therefore, when animal fiber is immersed in water,
endocuticle layer having lower cystine crosslinked density which is the innermost
layer, is swollen with water and extends, but on the contrary, the outer layer, exocuticle
layer, having higher cystine crosslinked density has less extent of water swelling
and therefore the extent of the expansion in the exocuticle layer is smaller. Such
difference of the expansion by difference of swelling produces the edge of uprising
of the scale and resulting the entanglement of fiber with fiber, causing felting.
[0037] More specifically, fibers are entangled with each other, and onto the entangled portions,
other fibers are entangled by an external force applied to the fabric at the time
of aqueous washing so that the entire fibers are drawn in the entangled portions,
causing shrinkage in the length of the entire fiber lump to form felt; thus, felting
results in further shrinkage.
[0038] The animal fiber of the present invention which is superior in shrink proofing and
pilling resistance is mainly realized by a chemical modification of the epidermal
tissue, and the swelling properties of the exocuticle B-layer and the endocuticle
layer are made virtually equal to each other with the water repellence property of
the eicosanoic acid on the uppermost surface being maintained so that, even when dipped
into water, the rising of the scales is virtually eliminated.
[0039] In other words, while the integral structural body of the epicuticle layer and the
exocuticle A-layer that is a hard structure in terms of the organized structure is
maintained, that is, while eicosanoic acid exerting repellency is maintained, only
the exocuticle B-layer is selectively attacked so that its cystine bond, that is,
its cross-linking structure, is broken. Only the portions of the surface of the fiber,
especially those related to swelling and shrinkage, are subjected to the modification,
with the inside of the fiber being protected; therefore, the resulting feature is
that the water repellence property of the entire fiber is maintained and the fiber
strength is also maintained.
[0040] The above-mentioned structural change by the treatment of the present invention is
confirmed by a reflection FT-IR measuring method (ATR method). The structure within
1µm from the surface is reflected by the reflection FT-IR measurements, and this is
equivalent to the thickness of the epidermal tissue of the animal fiber that is approximately
1µm. With respect to the FT-IR absorbance of the animal fiber that has been subjected
to the modifying treatment, both of relative absorbances in the absorption band of
1040 cm
-1 corresponding to the -SO
3H group (sulfonic acid group) and the absorption band of 1024 cm
-1 corresponding to the -S-SO
3Na group (Bunte salts), obtained in the case when the absorption band corresponding
to amide I (1650 cm
-1) is set to 1, have an increase in comparison with the relative absorbance of untreated
animal fibers, thereby indicating that the cross-linking bond of the exocuticle B-layer
has been cut.
[0041] In contrast, in the case of the animal fiber obtained through a chlorine treatment
method or a Chlorine-Hercosett method, etc. that is a typical conventional method,
the integral structural body of the epicuticle layer and the exocuticle A-layer is
directly attacked, and in particular, the epicuticle layer is severely damaged, with
the result that the water repellence layer is broken to lose its water repellence
property that the animal fiber originally features. In addition, since the oxidation
action is exerted to the entire fiber, resulting in degradation in the strength.
[0042] Moreover, the conventional shrink proofing animal fiber has a smoother scale surface
so that in comparison with the animal fiber of the present invention which maintains
the scales, there is a reduction in the single-fiber drawing abrasion resistance,
failing to provide sufficient pilling resistance.
[0043] Fig. 2 shows the results of surface observation under an electronic microscope of
the animal fiber of the present invention, the shrink proofing animal fiber treated
by the conventional method and a natural untreated animal fiber. In Fig. 2, (a) shows
an untreated wool fiber, (b) shows a chlorine-treated wool fiber, (c) shows a Chlorine-Hercosett
treated wool fiber and (d) shows a wool fiber of the present invention. In comparison
with the conventional shrink proofing animal fiber that has a quite smooth surface
with hardly any scales being observed, it is confirmed that the animal fiber of the
present invention maintains a surface state that is virtually the same as the natural
state.
[0044] Here, the animal fiber of the present invention includes wool, mohair, alpaca, cashmere,
llama, vicuna, camel and angora.
[0045] The animal fiber being relatively less performance in pilling property which has
the feature described above, can be produced by the method for preparation according
to the present invention described below.
[0046] Namely, the method for preparation of animal fiber of the present invention comprises
that sliver composed of animal fiber is, first, primary-oxidized with an oxidizer
having an ability to oxidize a cystine -S-S-bond of the animal fiber, and then, an
ozone-oxygen mixed gas is made into ultrafine bubbles of 5 µ or less in water by using
a line mixer and the gas in this condition is allowed to collide against the previously
primary-oxidized animal fiber for a given time to cause a gas-phase oxidation reaction
in the liquid, resulting in oxidation of the cystine bond of wool into higher order
oxidized state. Then, a reduction treatment is performed on the higher order-oxidized
animal fiber to cleave the cystine crosslinkage (-S-S-).:
[0047] And the method of the present invention also has the feature can continuously impart
the combined effect of shrink proofing and pilling resistance to the sliver of animal
fiber.
[0048] In the present invention, the primary-oxidized state of a cystine bond (-S-S-), namely,
lower order oxidized state means mono-oxidized state (-SO-S-), di-oxidized state (-SO
2-S-) or mixed state thereof. Particularly, it means the state rich in mono-oxidized
state. While, the higher order oxidized state means di-oxidized state, tri-oxidized
thereof.
[0049] It is known that though fission of a -S-S- bond by a reduc state (-SO
2-SO-), tetra-oxidized state (-SO
2-SO
2-) or mixed state ing agent is not easy and requires a longer time in the case of
mono-oxidized state, while in di, tri or tetra-oxidized state, fission is effected
relatively easily.
[0050] The present invention is characteristic in that it effects two-stage oxidation comprising
a first step in which animal fiber is subjected to primary oxidation treatment by
pad steaming with an oxidizer having an ability to oxidize a cystine -S-S- bond of
the animal fiber and a second step in which higher order oxidation is conducted by
blowing aqueous treatment liquid containing ozone in the form of ultrafine bubbles
of 5 µ or less in the aqueous treatment liquid, for cleaving a cystine bond only in
cuticle portions of animal fiber effectively, namely, in a short period of time without
unevenness treatment.
[0051] Then, a mixed gas of ozone and oxygen produced from an ozone generating apparatus
is blown in a liquid circulation pump, further, aqueous ozone treatment liquid containing
ozone in the form of ultrafine bubbles of 5 µ or less is prepared through a line mixer,
this liquid blown in water on animal fiber primary-oxidized, to ozone-oxidize quickly
and preferentially an exocuticle B layer in which a cystine -S-S- bond has been previously
oxidized to give higher order oxidized state in the B layer.
[0052] Then, a cystine (-S-S-) bond is cleaved by reduction treatment with a reducing agent,
for example, a sulfite, to lower the cystine crosslinked density of the exocuticle
B layer, as a result, swelling, fluidization and solubilization with water are promoted
and a part of protein is allowed to flow out of the fiber,
[0053] According to the present invention, the cystine crosslinked density of this exocuticle
B layer is reduced by performing pre-oxidation, ozone oxidation and reduction treatment
with a sulfite, and as a result of that, about the same level water swelling as that
of the endocuticle is obtained and bilateral function of the exocuticle B layer and
endocuticle is allowed to disappear. And therefore the edge of scale does not uprise
even when animal fiber is immersed in water, and shrinkage does not occur in aqueous
washing. Simultaneously, higher degree of shrink proofing is given without deteriorating
water repellency since an epicuticle layer and a thioester of eicosanoic acid covering
the surface thereof is still kept. And further, since scale is kept in the fiber,
withdrawing force of pulling out of a fiber in the fiber assembly is higher and fiber
movement in the fiber assembly is suppressed, resulting in correspondingly anti-pilling,
as compared with a shrink proofing method in which scale is peeled, descaled or a
shrink proofing method in which the surface of scale is coated with a resin.
[0054] The method for preparation of the animal fiber of the present invention is characteristic
in two-stage oxidation comprising a first step in which animal fiber is primary-oxidized
and a second step in which the primary-oxidized animal fiber is higher order-oxidized,
and in comprising a successive reduction step to cleave the higher order oxidized
cystine bond.
[0055] The method for preparation of the animal fiber of the present invention is described
more in detail below.
[0056] The first step in this method is a pre-treatment step for oxidation of a cystine
bond with ozone, and is a stage in which a cystine bond in cuticle tissue of the fiber
is primary-oxidized with an oxidizer having an ability to oxidize a -S-S- bond of
animal fiber to obtain substantially mono-oxidized state.
[0057] As the preferable oxidizer used for primary oxidation, persulfuric acid, peracetic
acid, performic acid, per-acids and neutral salts or acidic salts of these per-acids,
or potassium permanganate, hydrogen peroxide and the like are exemplified, and these
can be used alone or in admixture of two or more. Particularly preferable oxidizer
is potassium hydrogen persulfate.
[0058] The primary oxidation is conducted through pre-oxidation by a pad (impregnation)-steam
(reaction) method, in some occasions, by pad-store (reaction at room temperature).
Usually, when potassium hydrogen persulfate is used, an immersion method is adopted,
and in this case, a treating reagent permeates into inner portions of fiber and the
fiber or whole fiber is oxidized and hydrolyzed to cleave a cystine bond, causing
reduction in mechanical properties such as strength, elongation and the like. Nevertheless,
shrink proofing effect is not obtained. Further, in a method in which potassium hydrogen
persulfate is padded (impregnated) and stored (left at room temperature), reaction
with the fiber does not occur and cuticle is not oxidized sufficiently unless the
reaction temperature is room temperature or more (substantially, 32°C). In the present
invention, the treatment condition should be set depending on the kind of an oxidizer
used and reactivity thereof with the fiber, and in the case of use of potassium hydrogen
persulfate, the pad (impregnation)-steam (reaction with heat) method oxidizes a cystine
bond only in cuticle portions while preventing oxidation of inner portions of the
fiber, thereby, makes easy the subsequent higher order oxidation of cuticle portions
with ozone.
[0059] At this primary oxidation step, an exocuticle B layer is primarily oxidized at first
(first step). Comparing to exocuticle B layer, in the tissue of the epicuticle layer
and exocticle A layer being in contact with it, cystine -S-S- crosslinked density
is very high, and as a result, the tissue has very high hardness, and manifests chemical
resistance and abrasion resistance (this epicuticle part is tissue decomposed lastly
even by hydrolysis with 6N-hydrochloric acid. Therefore, epicuticle is treated as
a resistant membrane in histology). According to this, exocuticle B layer is more
susceptible to oxidation relatively in comparison with epicuticle layer and exocuticle
A layer.
[0060] Namely, in the first step , a wetting agent is put into a bath charged with an oxidizer
aqueous solution, the bath temperature is controlled as lower as possible than room
temperature, padding (impregnation) is effected so that liquid contact time with animal
fiber will be several seconds (about 2 to 3 seconds), the fiber is removed out of
the pad bath at a stage wherein the oxidizer aqueous solution does not reach inner
portions of the fiber and sufficiently permeates into cuticle, and immediately, squeezed
by a mangle so that add-on amount of the oxidizer aqueous solution becomes constant.
The fiber thus containing a given amount of the oxidizer aqueous solution is subsequently
treated at temperatures around 95°C in steamer, for promoting a primary oxidation
reaction while avoiding drying of the fiber.
[0061] Herein, the term "padding" does not mean impregnation of liquid into fiber by merely
putting the fiber in a bath but means impregnation so as not to cause a reaction in
the immersion bath in view of chemical reactivity of the oxidizer used with animal
fiber. It means poor reaction conditions, namely, selection of a wetting agent having
high permeability which is not decomposed with an oxidizer in a bath, control of the
temperature in a bath as low as possible to suppress a reaction with fiber, and immersion
for a short period of time such as several seconds and subsequent immediately squeezing.
[0062] The second step in the treatment method is a stage in which animal fiber primary-oxidized
with an oxidizer is higher order-oxidized with ozone. Usually, in oxidation with ozone,
a longer period of time is required, and formation of oxidation state sufficient for
cleaving of a cystine bond is difficult. That is, when animal fiber is oxidized with
ozone, it is necessary to treat the animal fiber with an ozone gas or ozone dissolved
in water of high concentration for 10 to 30 minutes, and under such conditions, continuous
treatment was impossible. However, in the present invention, higher order oxidation
with ozone in a short period of time with easiness has been made possible by conducting
primary oxidation in the first step as a pre-treatment method and rendering ozone
into specific state and simultaneously contriving contact method with fiber, and thus
continuous treatment step has become possible.
[0063] Namely, the present invention is characteristic in that ozone is dispersed in the
form of ultrafine bubbles of 5 µ or less at high concentration in water, and further,
this aqueous treatment liquid containing ozone in such state is blown to animal fiber,
to cause a gas-solid reaction with gas phase of ozone.
[0064] Development of an ultrafine bubbles scatter-preventing apparatus which collects ultrafine
bubbles of 5 µ or less discharged from a line mixer on the surface of a perforated
suction drum and the increase of the number of collision of the ultrafine bubbles
against fiber also contributed to completion of the present invention.
[0065] In oxidation treatment with ozone in the form of bubbles dispersed in water, the
presence of bubbles in water, in general, prevents wetting of fiber assembly with
liquid and exerts a reverse influence on wettability of liquid. In the present invention,
as means for solving this drawback, a means is adopted in which, first, top sliver
of animal fiber is sufficiently fiber-opened by a rotary gill to form a thin web like
belt, wound on the surface of a perforated suction drum, and an ozone-oxygen mixed
gas is made into ultrafine bubbles of 5 µ or less by using a line mixer, and the liquid
is sucked to increase the number of collision against fiber for allowing this ultrafine
bubbles to penetrate between fiber and fiber, thereby promoting ozone oxidation.
[0066] The present invention will be illustrated in detail according to a process shown
in Fig. 3. The animal fiber sliver used is, for example, a top of about 25 g/m, and
the nine ends of tops are fiber-opened using a gill to form a belt, and the draft
ratio is from about 1.4 to 4-fold, preferably 1.66-fold, though it varies depending
on fineness of wool. The feeding speed of a wool top is from 0.2 m/min to 4 m/min,
preferably from 0.5 m/min to 2 m/min.
[0067] The wool top shaped in the form of a belt is immersed in an aqueous solution containing
an oxidizer and wetting agent, and squeezed with a squeezing mangle. Examples of the
oxidizer include persulfuric acid, persulfates or acidic persulfates such as potassium
hydrogen persulfate, sodium hydrogen persulfate, ammonium persulfate, potassium persulfate
and sodium persulfate; potassium permanganate, hydrogen peroxide, performic acid or
salts thereof, peracetic acid or salts thereof, and the like. Particularly preferable
is potassium hydrogen persulfate [trade name: "Oxone" (2KHSO
5 · KHSO
4 · K
2SO
4, active composition is 42.8% as the proportion of KHSO
5) ; manufactured by E. I. du Pont de Nemours and Company] since it is in the form
of a granule, easily dissolved, and an aqueous solution containing the dissolved oxidizer
is stable for storage at a temperature of 32°C or less. As the wetting agent, "Alcopol
650" (manufactured by Chiba Specialty Chemicals K.K.) is preferable since it is stable
against an oxidizer. The concentration of the oxidizer is from 10 g/L to 50 g/L, preferably
from 20 g/L to 40 g/L when the squeezing ratio is 100% in the case of potassium hydrogen
persulfate "Oxone", though it differs depending on the kind of the oxidizer. The concentration
of the wetting agent is suitably about 2 g/L in the case of "Alcopol 650". The temperature
of the pad liquid is preferably as low as possible so as not to cause a reaction in
the liquid. Particularly preferably, it is from 15°C to 25°C. It is preferable that
pH of the liquid is on acidic side. More preferably, pH is 2.0.
[0068] After squeezing by a squeezing mangle, an oxidizer is allowed to react with animal
fiber sliver, and the treatment conditions vary depending on the kind of the oxidizer.
For example, in the case of potassium permanganate, hydrogen peroxide, performic acid
or peracetic acid, a method in which an aqueous solution of these compounds is padded,
and then, stored at room temperature is recommendable. The store time may advantageously
be about 2 to 10 minutes though it varies depending on the kind and concentration
of the oxidizer. While, in the case of potassium hydrogen persulfate, potassium persulfate,
sodium persulfate or ammonium persulfate, a primary oxidation reaction may advantageously
be conducted by steaming treatment at normal pressure, after padding of an aqueous
solution of these compounds. Regarding the steaming condition, a temperature of 95°C
and a time from 5 to 15 minutes, preferably of about 10 minutes are sufficient to
conducting primary oxidation.
[0069] One characteristic of animal fiber is that the cystine (-S-S-) content varies depending
on tissues constituting cuticle and cortex. In the present invention, particularly
modification of cuticle tissue is conducted for imparting shrink proofing and pilling
resistance . Oxidation of a cystine bond -S-S- progresses sequentially as described
below, and the -S-S- bond is cleaved after hydrolysis and reducing treatment, and
finally, sulfonic acid (-SO
3H) is obtained.
[0070] The present invention has a feature that a reaction is effected by a pad-steam method
with an oxidizer, for example, potassium hydrogen persulfate, a -S-S- bond is stopped
at substantially mono-oxidized state, and is further oxidized to higher order using
ozone in the subsequent step.
[0071] By adopting this operation, the ozone oxidation reaction rate increases remarkably
as compared with oxidation rate when ozone is solely used or potassium hydrogen persulfate
is solely used, and continuous treatment of animal fiber sliver becomes possible for
the first time, leading to success in industrialization, if a-S-S- bond is primary-oxidized
previously, and then, ozone-oxidized, as shown in the following formula:
[0072] The present invention is characteristic in that an ozone-oxygen mixed gas is allowed
to collide against animal fiber sliver by blowing the gas in the form of ultrafine
bubbles of 5 µ or less in water, to cause a higher order oxidation through a gas phase
reaction. Regarding the ozone generating apparatus, an ozonizer apparatus manifesting
a generating capacity of about 250 g/hr (for example, one manufactured by Chlorine
Engineering K.K.) can sufficiently effect continuous treatment of animal fiber sliver,
and for example, an ozone gas generated by feeding an oxygen gas at a rate of 40 L/min
into the ozonizer has a weight concentration of 6.5 wt% and a volume concentration
of 0.1 g/L in the mixed gas, and in one example, treatment with an ozone oxygen mixed
gas of 4 g/min was an optimum condition though it differs depending on the extent
of primary oxidation and other conditions. The feeding amount for imparting shrink
proofing and pilling resistance to wool fiber is 6%owf or less, preferably from 1.5%owf
to 5%owf based on the weight of wool, though it differs depending on the wool fiber
quality.
[0073] It is one feature of the present invention that, for reacting an ozone gas efficiently
with wool, the ozone gas is formed into bubbles which are as fine as possible in water,
the bubbles are allowed to collide against wool, and an oxidation is caused at the
collision site. Therefore, also since the water solubility of ozone is extremely low,
only cuticle tissue of wool is resultantly oxidized, and cortical tissue which is
inner tissue is protected, resulting in further enhancement of the effect to modify
the surface of wool. As the method for making an ozone-oxygen mixed gas into ultrafine
bubbles of 5 µ or less, a method is preferable in which the mixed gas is introduced
into a water flow pump and the mixed gas is allowed to collided against small walls
in a cylinder by raising water pressure to give ultrafine bubbles.
[0074] It is also a characteristic of the present invention that a special apparatus shown
in Fig. 4 was contrived for collecting ultrafine bubbles produced in a line mixer
and blowing the bubbles on wool sliver in the form of a belt. Wool sliver (2) in the
form of a belt which has been primary-oxidized is sandwiched between stainless mesh
belts (1) and (3) and transferred to an ozone treatment bowl (9) equipped with a suction
drum (5), where the ultrafine bubbles are blown on wool sliver in the form of a belt
through a nozzle (6) from a line mixer (13). And for collecting this ultrafine bubbles
at the wool sliver in the form of a belt, an ultrafine bubble-collecting apparatus
(4) is mounted on the periphery of a suction drum, and further, liquid containing
the ultrafine bubbles is sucked from the center portion (7) of the suction drum to
allow the ultrafine bubbles to collide against the wool sliver in the form of a belt.
An ozone-oxygen mixed gas produced from an ozonizer (11) is introduced in a water
suction pump (12) to cause gas-liquid mixing, and the mixture is fed to the line mixer
(13) by raising water pressure to produce ultrafine bubbles which are blown on wool
sliver in the form of a belt sandwiched between stainless mesh belts. Further, surface
oxidation of wool fiber is completed by using an apparatus sucking through a suction
port (7).
[0075] Though it is said that ozone is a strong oxidizer second to fluorine, the nature
is different at the acidic side and alkaline side. Namely, at the acidic side;
O
3 + 2H
+ + 2e
- = O
2 + H
2O E
o = 2.07 V
while, at the alkaline side;
O
3 + H
2O + 2e
- = O
2 + 2OH
- E
o = 1.24 V
and, standard oxidation potential is higher, and further, solubility of ozone in water
is higher and the half life is by far longer, at the acidic side.
(half life is 1 second when pH is 10.5 and 105 seconds when pH is 2.0)
[0076] The ozone oxidation is conducted at the acidic side of pH 1.5 to pH 2.5, preferably,
of pH 1.7 to pH 2.0. Ozone has higher solubility, however, lower reactivity, in cold
water. The treatment temperature has to be increased for enhancing the reactivity,
and the treatment temperature may advantageously be 30°C to 50°C, and when it is too
high, an ozone-oxygen mixed gas shows higher molecular movement, and is scattered
out of a treatment bowl. Particularly preferable temperature is 40°C. The reaction
time can control the reaction by the feeding speed of wool sliver, namely, the liquid
contact time in the ozone treatment bowl. When the feeding speed of sliver is 0.5
m/min, the contact time is 2 minutes, and when 2 m/min, the contact time is 33 seconds,
and control of shrink proofing and control of pilling resistance are possible by controlling
the reaction time.
[0077] The wool sliver ozone-oxidized in the ozone treatment bowl is treated with a reducing
agent, and therein, a -S-S-bond is cleaved for the first time as shown in the following
formula.
[0078] In this method, particularly an exocuticle B layer among cuticle tissues, is attacked,
and consequently, the cystine -S-S- crosslinked density decreases and swelling property
with water increases to the same water swelling level as that of endocuticle, and
consequently, bilateral property of scale of animal fiber disappears, preventing arising
of scale edge in water. Therefore, water repellent function which is a characteristic
of wool is not lost, and higher degree of shrink proofing and pilling resistance can
be imparted while keeping water repellency.
[0079] The reducing agent is not particularly restricted, and sulfites are suitable. Among
sulfites, sodium sulfite Na
2SO
3 (pH 9.7) is more preferable than acidic sodium sulfite NaHSO
3 (pH 5.5). Since primary oxidation and ozone oxidation are conducted at the acidic
side, reduction treatment at the alkaline side is preferable also from the standpoint
of neutralization treatment. The concentration of sodium sulfite is preferably from
10 g/L to 40 g/L, and particularly preferably around 20 g/L. The temperature is preferably
from 35°C to 45°C, and particularly preferably around 40°C.
[0080] It is preferable to conduct water rinsing in two steps while effecting over flow,
both for removing the remaining sulfite and for removing protein dissolved from the
treated wool. The temperature may advantageously be about 40°C.
[0081] After water rinsing, a softener and spinning oil agents may be added to the final
bowl in view of hand-feeling and spinning property of wool sliver. For example, treatment
can also be conducted at 40°C by adding
1 g/L of Alcamine CA New
(manufactured by Chiba Specialty Chemicals K.K.) and
1 g/L of Croslube GCL
(manufactured by CTC Textiles Ltd./Miki K.K.).
[0082] Drying is conducted preferably at relatively lower temperatures around 80°C in a
suction type drier for avoiding heat yellowing.
[0083] Various oxidation methods on animal fiber are compared and considered as follows.
A) In the case of oxidation only by ozone treatment:
1) Ozone has extremely low solubility in water, and it is 39.4 mg/L at 0°C, 13.9 mg/L
at 25°C and 0 mg/L at 60°C, and from the standpoint of continuous treatment of animal
fiber sliver, the treatment time becomes too long because of low concentration to
be suitable for the continuous treatment. 2) A large amount of an aqueous solution
containing dissolved ozone is required. 3) An apparatus generating ozone of high concentration
is necessary, increasing equipment investment. 4) when an ozone gas of high concentration
is used, a careful caution is required on an exhaust gas and working environment at
the spot.
B) In the case of comparison of an immersion method with a pad steam method, regarding
oxidation of potassium hydrogen persulfate and the like:
1) An ionic bond (-NH3+-OOC-) is one of side-chain bonds being involved in the stabilization of polymer chains
in animal fiber, and as the result that chemicals such as potassium hydrogen persulfate
is reacted at higher temperature for a longer period of time in an immersion batch
method, potassium ion(+), hydrogen ion(+) or persulfate ion(-) is attracted by -NH3+ or -OOC- and destroys the ionic bond, and further cleaves -S-S- bond. This leads to the
lowering of strength, elongation and the like of the fiber and the effect of shrink
proofing cannot be obtained.
2) On the other hand, in the method in which animal fiber is oxidized only by pad
steaming using potassium hydrogen persulfate, the step of padding operation is used
with the intention of immersing under the condition wherein animal fiber and potassium
hydrogen persulfate do not react. Therefore, the temperature of an aqueous solution
of potassium hydrogen persulfate (stabilization temperature of the aqueous solution,
20°C or lower) is lowered, immersion in this aqueous solution is effected for a short
period of time (2 to 3 seconds) using wetting agent at lower temperature, and immediately,
the animal fiber is impregnated with a certain amount of potassium hydrogen persulfate
by squeezing with a mangle. And then, this is heated by steaming, and resultantly,
a reaction can be conducted only in portions wherein the animal fiber contains the
reagent. In this method, the reagent does not invade into inner portions of the fiber
but results only in surface layer oxidation and the inner tissue is protected, contributing
to shrink proofing and pilling resistance indicating modification in the surface tissue
corresponding to the object of the present invention.
C) In the case of ozone treatment after pre-treatment with an oxidizer such as potassium
hydrogen persulfate and the like:
1) Once an animal fiber is primary-oxidized, it is easily oxidized quickly with ozone,
oxidation on animal fiber is completed in a short period of time, and continuous treatment
is made possible. 2) Due to previous primary-oxidation, an oxidation reaction is promoted
sufficiently with ozone of lower concentration, and consequently, a continuous treatment
of animal fiber sliver becomes possible sufficiently by an apparatus generating ozone
of lower concentration. 3) Due to the apparatus generating ozone of lower concentration,
working environment does not deteriorate. 4) Owing to the apparatus generating ozone
of lower concentration, equipment investment may be small.
[0084] As described above, the two-stage oxidation method used in the present invention
enables unexpected effective oxidation which has not been obtained by oxidation treatment
either with an oxidizer or ozone.
[0085] In the present invention, as described above, a cystine bond is cleaved uniformly
by higher order oxidation of animal fiber and the followed reduction treatment, and
resultantly, animal fiber endowed uniformly with shrink proofing and pilling resistance
is obtained by continuous steps. In the treated animal fiber obtained like this, the
exocuticle B layer is selectively attacked and the integrated structure of epicuticle
and exocuticle A layers which is a structurally hard tissue is preserved, and resultantly,
eicosanoic acid revealing water repellency is also kept and water repellency of the
whole fiber, and fiber strength is also maintained.
[0086] While, in a chlorination reaction of animal fiber, a cystine (-S-S-) bond is oxidized
and hydrolyzed to give sulfonic acid (-SO
3H), and since a peptide chain constituting animal fiber is cleaved in addition to
cleavage of a cystine bond, the tensile strength and elongation of fiber are lowered.
Also thioester bond tissue formed between eicosanoic acid which is the outermost film
of animal fiber and a -SH group in a polypeptide chain is broken, to convert the hydrophobicity
into the hydrophilicity. Therefore, water repellent function inherent to wool disappears.
[0087] A reaction mechanism by a chlorination reaction is shown below.
( | and - indicates a polypeptide chain.)
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[Examples]
Example 1
[0088] Wool sliver was treated continuously according to a process diagram described in
Fig. 3. The running speed of the sliver through processes, namely, a pad treatment
mangle, ozone treatment bowl, reducing treatment bowl, water rinsing treatment bowl
and drying processes was 2 m/min.
[Pad treatment process]
[0089] 9 ends of sliver (25 g/m) made of Merino wool of 20.7 from Australia were transferred
to a rotary gill, and the wool sliver was fiber-opened into a belt by drafting at
a ratio of 1.66. The belt sliver was padded in an aqueous solution having the following
composition and squeezed by a mangle.
Pad aqueous solution composition
[0090]
Potassium hydrogen persulfate KHSO5 : concentration is 40 g/L
("Oxone", manufactured by E. I. du Pont de Nemours and Company)
Wetting agent "Alcopol 650" : concentration is 2 g/L
(manufactured by Chiba Specialty Chemicals K.K.)
Treatment Condition
[0091]
Contact time: 2 seconds
Temperature: ordinary temperature
pH: 2.0
Squeezing rate: 100%
[0092] It was squeezed by a mangle, and then, transferred to a steam treatment process.
[Steam treatment process]
[0093] Wool sliver wetted in the form of a belt was subjected to steam treatment on a conveyor
net under the following conditions.
95°C, 10 min
[0094] After the steam treatment, the sliver was transferred to an ozone treatment bowl.
[Ozone treatment process]
[0095] The steam-treated sliver was transferred to a suction type ozone treatment bowl,
and ozone-oxidized under the following conditions.
[0096] Ozonizer ("OZAT CFS-3", manufactured by Chlorine Engineering K.K.) was used at 250
g/hr, and an oxygen bomb was used as an oxygen source.
Oxygen feeding speed to "Ozonizer OZAT CFS-3"; 40 L/min
Ozone generation weight concentration; 6.5 wt%
Ozone generation volume concentration; 0.1 g/L
Ozone generation amount; 4 g/min
Apparent ozone feeding amount to wool; 1.48%owf
[0097] The generated ozone gas was transferred to four line mixers through 4 pumps having
a water lifting amount of 80 L/min. The ozone blowing amount in each line mixer was
10 L/min, and the total amount was 40 L/min. The ultrafine bubbles were allowed to
collide against on the wool sliver on the suction drum by blowing the bubbles using
an ultrafine bubble-scattering-preventing apparatus as shown in Fig. 4, and further,
the treatment liquid was sucked from inside of the drum and was circulated to the
outer side of the drum for increasing the times thereof, and ozone treatment was conducted
under the following conditions.
Ozone bubbles; ultrafine bubbles of about 5 µ
Treatment temperature; 40°C
pH; 1.7 (adjusted with sulfuric acid)
Contact time; 33 seconds
[0098] After the ozone treatment, the sliver was transported to a reducing bowl.
[Reducing treatment process]
[0099] The ozone-treated sliver in the form of a belt was treated under the following conditions
in a suction type reducing bowl.
20 g/L; sodium sulfite Na2SO3
pH; 9.7
Temperature; 40°C
Contact time; 33 seconds
[0100] After the reduction treatment, the sliver was transported to a water rinsing bowl.
[Water rinsing treatment bowl]
[0101] The reduction-treated sliver in the form of a belt was treated with hot water of
40°C for 33 seconds in a suction type water rinsing bowl. After the water rinsing,
the sliver was further transported to another water rinsing treatment bowl.
[Water rinsing treatment bowl]
[0102] The sliver in the form of a belt was treated with hot water of 40°C for 33 seconds
in a suction type water rinsing treatment bowl. After the water rinsing, the sliver
was transported to the final bowl for imparting a spinning oil and softener necessary
for the subsequent processes.
[Spinning oil and softener treatment process]
[0103] The water-rinsed sliver in the form of a belt was treated with hot water of 40°C
for 33 seconds in a suction type treatment bowl charged with the following treating
agents.
Treating agent
[0104]
1 g/L of "Alcamine CA New"
(manufactured by Chiba Specialty Chemicals K.K.) and
1 g/L of "Croslube GCL"
(manufactured by CTC Textiles Ltd./Miki K.K.).
[0105] After the oiling-treatment, the sliver was transported to a drier.
[Drying process]
[0106] Drying was conducted at 80°C using a suction type hot air drier.
[0107] The treated sliver in the form of a belt was gilled and spun into hosiery yarn of
2/48Nm by twist of Z500×S300, and strength and elongation of the yarn were measured,
and knitted into a density of a cover factor C.F. of 0.41, and washed continuously
for 1 hour and 3 hours by a Cubex shrinkage testing apparatus. The fabric which had
been knitted into a C.F. of 0.41 was subjected to a pilling test for 5 hours by an
ICI pilling tester. For further investigating the property of the treated wool fiber,
the surface of the wool was observed by an electron microscope, S-3500N manufactured
by Hitachi. For measuring the water repellency of the treated wool, the sliver was
gilled to be fiber-opened, and each 1 g of the treated sliver and untreated sliver
was sampled, 800 mL of distilled water was charged into a 1-L beaker and the sample
was floated on the water surface and sedimentation condition was observed.
The results thereof are shown in Table 1.
[0108] The treated wool sliver was soft and showed white color, and shrink proofing thereof
based on WM TM31 method met the standard of area shrinkage percentage under the Wool
Mark washability requirement, and also, satisfied 4-th grade level of pilling resistance
in the ICI pilling test. The observation of the sedimentation state of 1 g of the
sample showed that both of the un-treated wool and the ozone-treated wool did not
precipitate even after left for a day and night and were floating on water surface
in the beaker, while, the wool treated by a chlorinated resin method (Chlorine Hercosett
method) sank beneath water surface in the beaker only after left for 2 to 3 minutes.
Though one of properties of animal fiber is that it has naturally water repellent
function, in the present invention, an epoch-making experiment result was obtained
that shrink proofing can be imparted without losing water repellent function owned
by natural wool. In the conventional shrink proofing method, a method in which chlorine-treated
wool surface is coated with a Hercosett resin (polyamide epichlorohydrin) is mainly
used. On the wool treated thereby, water repellent function tends to be lost and the
wool tends to be wetted and resultantly, body temperature is lowered due to high heat
conductivity of water, giving chilled feeling to wearer, though shrink proofing is
obtained. The surface of the treated wool was observed by using S-3500N low evacuated
electron-microscope manufactured by Hitachi which can observe the object in wet condition
showed that scale edge of the wool did not uprise, namely, differential frictional
effect (D.F.E) was not found, and on the contrary, in the un-treated wool, scale of
the wool uprose owing to swollen with water, which is a cause of felting. Therefore,
the present invention is a shrink proofing method which does not uprise scale edge
of wool in water.
Comparative Example 1
[0109] A sliver of 20.7 µ (25 g/m, 9 ends, draft ratio: 1.66-fold) of Merino wool from Australia
was continuously treated according to the method in Example 1 using. However, the
ozone treatment using an ultrafine bubble-scatter-preventing apparatus was omitted.
The results thereof are shown in Table 1. Though the treated wool was bleached, shrink
proofing and pilling resistance were approximately at the same level as those of the
un-treated wool, and no treatment effect was appreciated.
[0110] From comparison of Example 1 with Comparative Example 1, it became apparent that
on wool which had been treated previously with potassium hydrogen persulfate as a
pre-treatment process, oxidation progresses quickly with a small amount of ozone.
Namely, the present invention exemplified in Example 1 is an revolutionary method
in which wool fiber can be modified to impart shrink proofing and pilling resistance
with a small amount of ozone, and as the result, treatment effect is manifested sufficiently
with a small capacity of ozonizer, and consequently, equipment investment decreases
and exhaust gas treatment is reduced, and deterioration in working environment is
prevented.
Comparative Example 2
[0111] A sliver of 20.7 µ (25 g/m, 9 ends, draft ratio: 1.66-fold) of Merino wool from Australia
was continuously treated according to the method in Example 1 using. However, the
pre-treatment using potassium hydrogen persulfate was omitted. The results thereof
are shown in Table 1. Though the treated wool was somewhat bleached, shrink proofing
and pilling resistance were completely at the same level as those of the un-treated
wool.
Example 2
[0113] The treated wool sliver was gilled and spun into hosiery yarn of 2/48Nm by twist
of Z500×S300, and knitted into a density of a cover factor C.F. of 0.41, and continuous
washing tests for 1 hour and 3 hours by a Cubex shrinkage testing apparatus, and further,
a pilling test for 5 hours using an ICI pilling tester were conducted, and strength
and elongation of the knitted yarn were measured. For observing modification state
of the surface of the wool, 1 g of the treated sliver was fiber-opened by a gill,
800 mL of distilled water was charged into a 1-L beaker and the sliver was floated
on the water surface and sedimentation condition was observed.
[0114] The results of the tests are shown in Table 1. The treated wool sliver was soft and
also reveals whiteness, and further, by increasing the ozone feeding amount by about
3.6-fold of that in Example 1, shrink proofing was much superior to the Wool Mark
washability requirement, and such high degree of pilling resistance that the result
of an ICI pilling test was 5-th grade even after 5 hours was obtained. Since the reaction
amount of ozone was increased, strength and elongation of the knitted yarn somewhat
decreased, and regarding water repellent resistance, in the case of chlorine-treated
wool, completion precipitation to beneath water surface was observed, and this treated
wool revealed slight reduction as compared with natural non-treated wool.
Example 3
[0115] The same processes as Example 1 were carried out except that the contact time of
the ozone treatment was set to one minute so that a shrink proofing treatment was
carried out on Merino wool of 20.7 micron from Australia. The resulting shrink proofing
wool fiber was evaluated on its properties, and the results are listed in Table 2
in comparison with untreated wool, chlorine treated wood and Chlorine-Hercosett treated
wool. Moreover, electronic microscopic photographs of the fiber surface are shown
in Fig. 1, and the results of water repellency tests using a water droplet dripping
method onto a knitting fabric are shown in Fig. 5.
[0116] With respect to the evaluation of the properties in Table 2, as described earlier,
the felting shrinkage rate was measured in conformity with WM TM31 method and the
fabric knitted into a cover-factor C.F. 0.41 with one line being taken from 14 gages
was used as a sample. The pilling resistance was measured by a pilling test method
in accordance with JIS L 1076.6. 1A by using the fabric knitted by IP18G. Moreover,
the coefficient of friction µ
a in the tip to root direction to the scale direction of the single fiber and the coefficient
of friction µ
w in the root to tip direction to a fiber direction were measured in conformity with
JIS L 1015 under the conditions of a hanging line load of 200 mg and a cylinder peripheral
velocity of 90 cm/min.
[0117] Moreover, with respect to FT-IR, the fiber itself was measured by a reflection method
(ATR method). The figures are given as relative absorbances of the absorption bands
corresponding to the -SO
3H group and the -S-SO
3Na group in the case when the absorbance of the absorption band corresponding to amide
I is set to 1.
[0118] Table 2 shows the results of evaluation on the dying property by the use of a basic
dye that provides a measure for the existence of sulfonic acid groups.
[0119] Moreover, in order to confirm the existence of the epicuticle layer, evaluation was
carried out by using the Allwörden reaction. The results thereof are shown in Fig.
6.
[0120] As clearly indicated by these data, differently from the conventional shrink proofing
fibers, the shrink proofing wool fiber of the present invention allows scales to remain
in the same degree as the natural untreated wool (Fig. 1), thereby maintaining a better
water repellence property (Fig. 5).
[0121] Moreover, the pilling resistance is remarkably improved as compared with those conventional
treated fibers that have only little improvements.
[0122] Furthermore, the felting shrinkage rate is greatly improved, and the difference in
the coefficients of friction (static friction and dynamic friction) of the single
fiber, which provides one measure for the felting shrinkage rate, that is, the difference
"µ
a -µ
w" between the coefficients of friction in the tip to root direction and in the root
to tip direction with respect to a fiber direction, becomes smaller, thereby making
the anisotropy smaller.
[0123] The FT-IR data shows that, in comparison with the other fibers, the shrink proofing
improved fiber of the present invention has much more sulfonic acid groups (-SO
3H) and Bunte salts (-S-SO
3Na), which indicate a higher order oxidized state, generated on the surface thereof,
thereby indicating that the surface oxidation has been carried out efficiently.
[0124] As shown in Fig. 6, in the animal fiber of the present invention, the generation
of bubbles was observed through the Allwörden reaction in the same manner as the untreated
animal fiber, thereby indicating that the epicuticle layer sufficiently existed. In
contrast, in the case of "chlorine-treated wool" and "Chlorine-Hercosett-treated wool",
no bubbles were generated, indicating that the epicuticle layer had been broken.
[0125] The "chlorine-treated wool" and the "Chlorine-Hercosett-treated wool", evaluated
for comparative purposes, were prepared as described below:
Preparation of chlorine treated wool:
[0126] Wool sliver was successively dipped in a chlorine treatment bath, and this was squeezed
by a squeezing roll, and then dipped in an anti-chlorine treatment bath, and this
was squeezed by a squeezing roll, washed with water, and then dried.
[0127] Chlorine treatment: Chlorine gas was blown into water so as to set an amount of active
chlorine in the range of 1.8 % to 2.0 % owf with respect to the weight of wool, and
the treatment was performed at pH 2.0 in cold water for several tens of seconds.
[0128] Anti-chlorine treatment: Sodium sulfite (40 g/L) was adjusted to pH 0.9 by using
sodium bicarbonate, and the treatment was performed at 30°C for several tens of seconds.
[0129] Washing treatment: The resulting fibers were dipped in a washing bath at 40°C for
several tens of seconds, and then squeezed by a squeezing roll.
[0130] Drying treatment: The resulting fibers were dried by using a suction-type drier.
Preparation of Chlorine-Hercosett-treated wool:
[0131] After the above-mentioned chlorine treatment, anti-chlorine treatment and water washing
treatment, the resulting wool sliver was dipped in a processing bath in which Hercosett
resin WT-570 (made by Dick Hercules Co., Ltd.) had been dissolved, and this was squeezed,
and then dipped in a treatment bath containing a softening agent and a spinning oil,
squeezed, and then dried.
[0132] Hercosett resin treatment: The resin bath concentration was set to 2 owf with respect
to the weight of wool, the bath pH being adjusted to pH 7.5 with sodium bicarbonate,
and the treatment was performed at 35°C for several tens of seconds, and the resulting
wool was squeezed by a squeezing roll.
[0133] Softening treatment: The bath temperature was adjusted so that Alcamine CA-New (made
by Chiba Specialty Chemicals K.K.) serving as a softening agent was set to 0.5 % owf
with respect to the weight of wool and Croslube GCL (made by CTC Textiles Ltd./Miki
K.K.) serving as a spinning oil was set to 1.35 % owf with respect to the weight of
wool, and the treatment was performed at 30°C for several tens of seconds, and the
resulting wool was squeezed by a squeezing roll.
[0134] Drying treatment: The resulting wool was dried by a suction-type drier.
[Table 2]
|
|
Untreated |
Chlorine treated |
Chlorine-Hercosett treated |
Example 3 |
Felting shrinkage rate (% area) |
Cubex 1hr |
-58.2 |
4.0 |
-0.7 |
-0.4 |
Cubex 3hr |
-72.1 |
-6.2 |
-3.5 |
-3.9 |
Coefficient of static friction of single fiber |
µa |
0.335 |
0.270 |
0.232 |
0.351 |
µw |
0.132 |
0.216 |
0.174 |
0.235 |
µa-µw |
0.203 |
0.054 |
0.058 |
0.116 |
Coefficient of dynamic friction of single fiber |
µa |
0.313 |
0.249 |
0.240 |
0.320 |
µw |
0.189 |
0.211 |
0.199 |
0.273 |
µa-µw |
0.124 |
0.038 |
0.044 |
0.047 |
Scales (Observation under electronic microscope) |
○ |
× |
× |
○ |
Pilling (Class) |
1-2 |
2 |
2 |
3-4 |
Dyeing property (Astrazon Blue) |
Slightly pale color |
Highly dark color |
Intermediate dark color |
Highly dark color |
FT-IR |
-SO-S- |
0.07 |
0.05 |
0.06 |
0.06 |
-SO2-S- |
0.02 |
0.02 |
0.02 |
0.02 |
-SO3H |
0.06 |
0.12 |
0.14 |
0.16 |
-S-SO3Na |
0.03 |
0.12 |
0.08 |
0.28 |
Water repellency (Water droplet dipping method) |
○ |
× |
× |
○ |
Note: In the Table, minus (-) indicates shrinkage. |
[0135] With respect to the evaluation items of Table 2, the evaluation methods of those
items other than the already mentioned felting shrinkage rate, single fiber coefficient
of friction, pilling resistance, FT-IR measurement and water repellence property,
will be described below.
[Confirmation of existence of epicuticle layer]
[0136] Allwörden reaction: Several wool single fibers were put on a glass plate, and several
droplets of saturated bromine water were dropped thereon, and immediately after this,
the state of the surface of each fiber was observed under an optical microscope. When
any epicuticle layer existed, bubbles would be generated on the surface of the fiber.
Therefore, the existence of any epicuticle layer was confirmed depending on the generation
of bubbles.
[Existence of scales]
[0137] An electronic microscope was used to observe scales.
[Dyeing property by basic dye]
[0138] In a water solution containing 1g/L of Astrazon Blue 3RL (made by Bayer Corp.) and
1 ml/L of a nonionic wetting agent were dipped wool fibers in a bath ratio of 1:100,
at 20°C for 5 minutes, and this was then washed with water, and observed to find their
dyed state.
[0139] The darkish the dyed state, the more the sulfonates formed through oxidation.
[0140] The present invention makes it possible to provide an animal fiber having superior
shrink proofing and pilling resistance without impairing a water repellent property
that animal fibers originally possess as a superior feature, as well as without causing
degradation in the fiber mechanical properties. Moreover, the present invention also
provides a manufacturing method of the animal fiber having the above-mentioned features,
without using a toxic chemical such as chlorine, etc. In addition, the method used
in the present invention makes it possible to carry out a continuous processes, and
consequently to provide a useful method from the industrial point of view.