U.S. patent application number 10/792889 was filed with the patent office on 2004-09-02 for acrylic composite fiber and method for production thereof, and fiber composite using the same.
This patent application is currently assigned to Mitsubishi Rayon co., Ltd.. Invention is credited to Akasaka, Masanori, Hoshino, Masakazu, Kasabou, Yukio, Ochi, Ryo, Sakurai, Eizou, Takeuchi, Satoru.
Application Number | 20040170835 10/792889 |
Document ID | / |
Family ID | 26618504 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040170835 |
Kind Code |
A1 |
Takeuchi, Satoru ; et
al. |
September 2, 2004 |
Acrylic composite fiber and method for production thereof, and
fiber composite using the same
Abstract
An object of this invention is to provide an acrylonitrile based
composite fiber having a new feeling different from that of an
ordinary cellulose acetate fiber, cellulose fiber and acrylic
fiber, excellent spinability, fiber properties and process ability
of yarn spinning, and excellent functions, in particular, a
deodorizing function and a moisture absorbing and retaining
property. The composite fiber is comprised of 10 to 40% by weight
of cellulose acetate and/or cellulose and 60 to 90% by weight of an
acrylonitrile based polymer, and has a structure with the cellulose
acetate and/or cellulose forming an island component in a cross
section perpendicular to a fiber axis and the acrylonitrile based
polymer forming a sea component. Preferably, the cellulose acetate
and/or cellulose as the island component communicate with another
island component in the fiber axis direction, a vacant hole is
provided inside the fiber, or a ratio of the longest diameter and
the shortest diameter of the fiber cross section is 2 or less, and
5 or more recess parts of 0.3 .mu.m or more and 3 .mu.m or less
width and 0.3 .mu.m or more and 3 .mu.m or less depth are provided
in a fiber cross section outer circumferential part. Further
preferably, by applying a heat treatment under alkali in a
production stage, the moisture absorbing and retaining property can
be improved.
Inventors: |
Takeuchi, Satoru;
(Hiroshima, JP) ; Hoshino, Masakazu; (Hiroshima,
JP) ; Ochi, Ryo; (Hiroshima, JP) ; Kasabou,
Yukio; (Osaka, JP) ; Sakurai, Eizou; (Aichi,
JP) ; Akasaka, Masanori; (Osaka, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Mitsubishi Rayon co., Ltd.
Tokyo
JP
|
Family ID: |
26618504 |
Appl. No.: |
10/792889 |
Filed: |
March 5, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10792889 |
Mar 5, 2004 |
|
|
|
10482416 |
Jan 12, 2004 |
|
|
|
10482416 |
Jan 12, 2004 |
|
|
|
PCT/JP02/02603 |
Mar 19, 2002 |
|
|
|
Current U.S.
Class: |
428/393 |
Current CPC
Class: |
Y10T 428/2931 20150115;
Y10T 428/2924 20150115; D01F 6/54 20130101; Y10T 428/2975 20150115;
Y10T 428/2965 20150115; Y10T 428/2929 20150115 |
Class at
Publication: |
428/393 |
International
Class: |
D02G 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2001 |
JP |
2001-210366 |
Mar 14, 2002 |
JP |
2002-70368 |
Claims
1. An acrylic based composite fiber characterized by being composed
of 10 to 40% by weight of cellulose acetate and/or cellulose and 60
to 90% by weight of an acrylonitrile based polymer, comprising a
structure with the cellulose acetate and/or cellulose forming an
island component in a cross section perpendicular to a fiber axis,
and the acrylonitrile based polymer forming a sea component.
2. The acrylic based composite fiber according to claim 1,
characterized by comprising a structure with the cellulose acetate
and/or cellulose as the island component communicating with another
island component in a cross section along the fiber axis
direction.
3. The acrylic based composite fiber according to claim 1 or 2,
characterized by comprising a vacant hole inside the fiber.
4. The acrylic based composite fiber according to any of claims 1
to 3, characterized in that a ratio of the longest diameter and the
shortest diameter of a fiber cross section is 2 or less, and 5 or
more recess parts of 0.3 un or more and 3 .mu.m or less width and
0.3 .mu.m or more and 3 .mu.m or less depth are provided in a fiber
cross section outer circumferential part.
5. The acrylic based composite fiber according to any of claims 1
to 4, characterized in that single fiber strength is 1.8 CN/dTex or
more, dry elongation is 30% or more, knot strength is 1.8 CN/dTex
or more, and knot elongation is 30% or more.
6. The acrylic based composite fiber according to any of claims 1
to 5, characterized in that a deodorizing ratio with respect to a
carboxylic acid is 90% or more.
7. The acrylic based composite fiber according to any of claims 1
to 6, characterized in that the deodorizing ratio with respect to
an acetic acid is 95% or more.
8. The acrylic based composite fiber according to any of claims 1
to 7, characterized in that the deodorizing ratio with respect to a
nonanal is 90% or more.
9. The acrylic based composite fiber according to any of claims 1
to 8, characterized in that a moisture absorbing ratio Aa under a
40.degree. C. temperature and 90% RH humidity environment is 15.0%
or less, a moisture absorbing ratio Ab under a 20.degree. C.
temperature and 65% RH humidity environment is more than 2%, and a
moisture absorbing ratio difference .DELTA.A (=Aa-Ab) at the time
of transfer from the 40.degree. C. temperature and 90% RH humidity
environment to the 20.degree. C. temperature and 65% RH humidity
environment is less than 1.5.
10. The acrylic based composite fiber according to claim 9,
characterized in that the moisture absorbing ratio Aa under the
40.degree. C. temperature and 90% RH humidity environment is 3.0%
or more and 8.0% or less, and the moisture absorbing ratio Ab under
the 20.degree. C. temperature and 65% RH humidity environment is
more than 2% and less than 6.5%.
11. A method for producing an acrylic based composite fiber,
characterized by executing a wet spinning process using a spinning
solution obtained by mixing the below-mentioned components (A), (B)
and (C): (A) cellulose acetate, (B) an acrylonitrile based polymer,
and (C) a solvent capable of dissolving both the cellulose acetate
and the acrylonitrile based polymer.
12. A method for producing an acrylic based composite fiber,
characterized by spinning by using a spinning solution obtained by
mixing a solution with the component (A) dissolved in the component
(C) and a solution with the component (B) dissolved in the
component (C), each component (A), (B) and (C) being recited in
claim 11.
13. A method for producing an acrylic based synthetic fiber,
characterized by comprising a step of applying a heat treatment
under alkali to an acrylic based synthetic fiber composed of 10 to
40% by weight of cellulose acetate and 60 to 90% by weight of an
acrylonitrile based polymer, the acrylic based synthetic fiber
having a structure with the cellulose acetate forming an island
component in a cross section perpendicular to a fiber axis and the
acrylonitrile based polymer forming a sea component.
14. The method for producing an acrylic based composite fiber
according to claim 13, characterized in that a weight reduction
ratio of the cellulose acetate is 5 to 40%.
15. A fiber composite characterized by using the acrylic based
composite fiber according to any of claims 1 to 10.
Description
TECHNICAL FIELD
[0001] This invention relates to an acrylic based composite fiber
comprising cellulose acetate and/or cellulose, and an acrylonitrile
based polymer, a method for producing the same, and a fiber
composite using the same and another fiber, such as a knitted woven
fabric and a non-woven fabric.
BACKGROUND ART
[0002] An acrylic fiber having an excellent color developing
property, bulkiness, heat retaining property and soft feeling is a
material used widely in a clothes field, accessory field, interior
field, material field or the like, and it is developed mainly by
staple. In contrast, cellulose acetate having an excellent
glossiness, color developing property and dry feeling is regarded
as a high quality clothes material, and it is developed mainly by
tow and filament. However, since it does not have a fiber physical
property durable for yarn spinning, it is not developed by
staple.
[0003] Recently, development of a new material having a new feeling
and functions, such as one having a deodorizing function and a
moisture absorbing and retaining function in particular, is highly
demanded, and as a method for developing techniques, there is
polymer compositing. Complexing of a polymer is an effective method
for reciprocating material characteristics of each other. Several
reports have been provided on the polymer compositing technique of
cellulose acetate and an acrylonitrile based polymer. As to the
feeling, for example, a technique for compositing cellulose acetate
and an acrylonitrile based polymer is disclosed in Japanese Patent
Application Laid-Open (JP-A) Nos. 2-154713, and 3-234808. JP-A No.
2-154713 is for one having a feeling inherent to a conventional
acetate fiber, and JP-A No. 3-234808 is for one having a feeling
inherent to a conventional dry acrylic based fiber.
[0004] As to the deodorizing function, for example, JP-A No.
1-259867 discloses a technique for orienting a metal ion to an
amide oximated fiber. However, according to the technique, since
the fiber is colored by a hue inherent to the metal, a problem is
involved in that an end use is limited. Furthermore, a technique
for adding a silicate metal salt or an aminomo silicate metal salt
to an acrylic based copolymer (JP-A Nos. 9-1769175 and 9-291416)
has been proposed. Since the technique requires a copolymer having
acrylonitrile as a principal constituent unit and a non compatible
polymer having miscibility in addition to an additive, a production
process is complicated. Additionally, although a technique for
containing a titanium oxide having a photo catalyst function in a
fiber (JP-A No. 10-8327) has been proposed, it does not function
effectively at a place whereat ultraviolet rays are weak.
[0005] Moreover, as to the moisture absorbing function, which is
often applied by a post-process, washing resistance is poor.
Therefore, a binder such as acrylic resin, an urethane resin and an
epoxy resin is needed for improving durability, which deteriorates
the feeling of the fiber itself, and thus it is problematic.
Furthermore, a technique for compositing a moisture absorbing and
discharging component in a synthetic fiber has been proposed.
Although the technique (JP-A No. 11-279842) has both a moisture
absorbing function and a moisture discharging function, no
description is disclosed for a moisture retaining function
thereof.
[0006] In order to solve the above-mentioned conventional problems,
an object of the invention is to provide an acrylic based composite
fiber having a new feeling different from that of a conventional
cellulose acetate fiber, cellulose fiber and acrylic fiber,
excellent fiber physical properties and process ability of yarn
spinning, and excellent function properties, in particular, a
deodorizing function and moisture absorbing and retaining
function.
DISCLOSURE OF THE INVENTION
[0007] As a result of elaborate discussions by inventors of this
invention for solving the above-mentioned problems, the following
invention has been attained. The object of the invention is an
acrylic based composite fiber composed of 10 to 40% by weight of
cellulose acetate and/or cellulose and 60 to 90% by weight of an
acrylonitrile based polymer, characterized by comprising a
structure with the cellulose acetate and/or cellulose forming an
island component in a cross section perpendicular to a fiber axis
(fiber lateral cross section), and the acrylonitrile based polymer
forming an sea component, a method for producing the same, and a
fiber composite using the above-mentioned composite fiber.
[0008] As mentioned above, as a method for developing a new
material having a new feeling, compositing of a polymer is
effective. The inventors surprisingly found out, while promoting
discussions for a polymer compositing technique concerning the
cellulose acetate and/or cellulose and an acrylonitrile based
polymer, that the cellulose acetate and/or cellulose have/has a
high deodorizing function with respect to a carboxylic acid, in
particular to an acetic acid. Accordingly, it was suggested that by
using the cellulose acetate and/or the cellulose as a constituent
component of a fiber product, the deodorizing function can be
realized by an ability of a fiber substrate itself without using a
common deodorizing agent.
[0009] Furthermore, it was confirmed that an excellent moisture
absorbing and retaining property, which was not provided in
conventional acrylic based synthetic fibers, was obtained by using
the cellulose acetate and/or cellulose and the acrylonitrile based
polymer since high standard moisture regain of a fiber made of the
cellulose, such as the cellulose acetate and cotton, could be
effectively utilized. Therefore, it was also confirmed that by
using the cellulose acetate and/or the cellulose as a constituent
component of a fiber product, moisture absorbing and retaining
performance could be realized by an ability of a fiber substrate
itself without relying on a post process.
[0010] In the invention, cellulose diacetate and cellulose
triacetate can be presented as the cellulose acetate. The cellulose
diacetate in the invention has an average acetylation degree of
48.8% or more and less than 56.2%, and the cellulose triacetate has
an average acetylation degree of 56.2% or more and less than 62.5%.
The cellulose in the invention may be a polymer containing a
cellulose molecular structure C.sub.6H.sub.7O.sub.2(OH).sub.3, and
it may be a cellulose derivative with a chemical modification added
to a part of a hydroxyl group, such as alkyl cellulose, nitro
cellulose, cellulose xanthate, and ion exchange cellulose as
well.
[0011] In the invention, the acrylonitrile based polymer is made of
acrylonitrile and an unsaturated monomer polymerizable therewith.
As the unsaturated monomer, an acrylic acid, a methacrylic acid,
alkyl esters thereof, vinyl acetate, acrylic amide, vinyl chloride,
vinylidene chloride, and furthermore, depending on a purpose, an
ionic unsaturated monomer such as sodium vinyl benzene sulfonate,
sodium methacrylic sulfonate, sodium allyl sulfonate, sodium
acrylic amide methyl propane sulfonate, and sodium parasulfophenol
methacrylic ether may be used as well.
[0012] According to the composite fiber of the invention, the
cellulose acetate and/or cellulose need to be 10 to 40% by weight,
preferably 20 to 30% by weight. In the case where they are less
than 10%, a feeling of a fiber becomes similar to that of the
acrylic fiber and a dry feeling is lost. In addition, as to a
deodorizing ratio of a deodorizing evaluation to be described
later, a carboxylic acid is less than 90% and an acetic acid is
less than 95%, and thus a high deodorizing ability cannot be
obtained. In the case where they are more than 40%, spinability
becomes poor, for example fiber breaks are generated at the time of
production, and a fiber property is lowered, so that a process
ability of yarn spinning becomes poor. Moreover, a soft feeling
derived from the acrylic fiber is lost.
[0013] According to the invention, the acrylonitrile based polymer
needs to be 60 to 90%, preferably 70 to 80% by weight. In the case
where it is less than 60% by weight, the spinability becomes poor,
and the fiber physical property is lowered, so that the spinning
process passing property becomes poor. Moreover, the soft feeling
derived form the acrylic fiber is lost. In the case where it is
more than 90% by weight, a feeling of a fiber to be obtained
becomes similar to the feeling of the acrylic fiber so that the dry
feeling is lost.
[0014] According to the invention, it is important that, in a fiber
cross section, the cellulose acetate and/or cellulose form an
island component, and the acrylonitrile based polymer forms a sea
component for obtaining the fiber physical property defined in the
invention. By adopting the structure with the cellulose acetate
and/or cellulose being the island component and the acrylonitrile
based polymer being the sea component in the fiber cross section,
circumference of the cellulose acetate and/or cellulose, which have
vulnerable fiber properties, is covered with the acrylonitrile
based polymer, and consequently the fiber is reinforced so as to
obtain the fiber physical property equivalent to the ordinary
acrylic fiber. Moreover, in order to obtain the fiber physical
property equivalent to the ordinary acrylic fiber, a smaller island
size is considered to be advantageous, however, as long as the
fiber physical property defined in the invention is satisfied, the
island size is not at all limited.
[0015] It is preferable that the sea island structure in the cross
section in the direction perpendicular to the fiber axis (fiber
lateral cross section) has the cellulose acetate and/or cellulose
as the island component in the cross section in a fiber axis
direction (fiber longitudinal cross section) communicating with
another island component totally or partially for improving the
deodorizing function.
[0016] In the invention, a vacant hole denotes a gap formed inside
the fiber. A part of the vacant hole may be opened to a fiber
surface, and moreover, the vacant hole may interlock the islands
with each other. A form and a size of the vacant hole are not
limited at all. Since it is preferable to maintain a fiber strength
at 1.8 CN/dTex or more, those of about less than 2 to 5 .mu.m are
preferable though it depends on the form of the vacant hole.
Furthermore, according to the invention, although a dense structure
without a vacant hole inside the fiber is considered to be
advantageous for maintaining the fiber physical property, existence
or absence of the vacant hole is not at all limited as long as the
fiber physical property defined in the invention is satisfied. In
the case of an application for the purpose of retaining temperature
and light weight, it is rather advantageous to provide the vacant
hole.
[0017] As to the feeling of the fiber to be obtained, by satisfying
a ratio of the longest diameter and the shortest diameter of the
fiber cross section and a number of recess parts in a fiber cross
section outer circumferential part, dry, tense, and soft feelings
can be provided, which is different from conventional fibers, for
example, cellulose acetate fiber, fibers made of cellulose such as
cotton, rayon, cupra, or the like, and an acrylic fiber. In
addition, it is also effective for the deodorizing.
[0018] That is, it is preferable that the ratio of the longest
diameter and the shortest diameter of the fiber cross section is 2
or less, and 5 or more recess parts of 0.3 .mu.m or more and 3
.mu.m or less width and 0.3 .mu.m or more and 3 .mu.m or less depth
are provided in the fiber cross section outer circumferential part
for the new feelings and improving the deodorizing effect. The
longest diameter in the invention is a diameter of a circumscribing
circle in contact with the fiber cross section outer
circumferential part, and the shortest diameter is a diameter of a
inscribed circle in contact with the fiber cross section outer
circumferential part. The recess part in the fiber cross section
outer circumferential part in the invention is a recess part
recognizable visually with an optical microscope, having width and
depth of 0.3 .mu.m or more, which is the lowest limit of a
wavelength area of visible light.
[0019] Moreover, the width and the depth of the recess part are 3
.mu.m or less. If the recess part is in this range, since it is
much smaller than a rain droplet diameter (100 .mu.m to 3,000
.mu.m), and it is much larger than water vapor (0.0004 .mu.m)
("Special Functional Fiber" published by CMC, p182, 1983), only the
water vapor can pass through the recess part and the water vapor
can easily be diffused to the outside, and thus the dry feeling
tends to be generated. Furthermore, depending on a number of
existing recess parts, color effect which has not been
conventionally provided can be expected.
[0020] Since the ratio of the longest diameter and the shortest
diameter of the fiber cross section is 2 or less, bending rigidity
is increased so as to provide an appropriate tense feeling, and
since 5 or more recess parts of 0.3 .mu.m or more and 3 .mu.m or
less width and 0.3 .mu.m or more and 3 .mu.m or less depth are
provided in the fiber cross section outer circumferential part, the
dry feeling is generated, and friction resistance between the
fibers is reduced, so that the soft feeling can be provided. In the
case where the ratio of the longest diameter and the shortest
diameter of the fiber cross section is more than 2, the tense
feeling is lost, and in the case where the recessed parts of 0.3
.mu.m or more and 3 .mu.m or less width and 0.3 .mu.m or more and 3
.mu.m or less depth are provided in the fiber cross section outer
circumferential part are provided by less than 5, the dry feeling
and the soft feeling tend to be lost.
[0021] According to the invention, it is preferable that single
fiber strength is 1.8 CN/dTex or more, dry elongation is 30% or
more, knot strength is 1.8 CN/dTex or more, and knot elongation is
30% or more. Within these ranges, in general, process ability of
yarn spinning equivalent to that of ordinary acrylic fiber can be
obtained. In the case where the defined fiber physical properties
are not satisfied, that is, if the single fiber strength is less
than 1.8 CN/dTex, the dry elongation is less than 30%, the knot
strength is less than 1.8 CN/dTex, or the knot elongation is less
than 30%, the process ability of yarn spinning becomes poor.
[0022] The carboxylic acid in the invention, any one having a
carbonyl group in a molecule, and capable of being present in the
air can be used. Moreover, the carboxylic acid may be any of a
monocarboxylic acid, a dicarboxylic acid, and polycarboxylic acid,
and it may be saturated or unsaturated. Furthermore, a structure
having a functional group other than the carbonyl group may be used
as well. Carboxylic acid species are not particularly limited as
long as the above-mentioned conditions are satisfied. For example,
those having an unpleasant strange odor or stimulus odor in a daily
life, such as a formic acid, an acetic acid, a propionic acid, a
lactic acid, an isolactic acid, a valeric acid, an isovaleric acid,
a capronic acid, a 2-ethyl lactic acid, a capric acid, a 2-ethyl
hexanic acid and an oleic acid, can be presented.
[0023] As to adsorption performance, it is important that a
adsorption ratio of the carboxylic acid is 90% or more in the air
including 100 ppm or less carboxylic acid by a measurement method
to be described later. Carboxylic acid concentration in the air is
set at 100 ppm as a practical evaluation density based on a daily
life. In the case where the carboxylic acid adsorption ratio in the
air including 100 ppm or less carboxylic acid is less than 90%, the
adsorption ability is insufficient. Furthermore, in the case where
the carboxylic acid adsorption ratio in the air including 100 ppm
or less carboxylic acid is less than 90%, tolerant concentration of
the acetic acid as a representative example of the stimulus odor of
the carboxylic acid species, which is 10 ppm, (Principal Chemical
Products 1,000 Kinds Toxicity Data Special Research Report, p19,
Kaigai Gijutsu Shiryo Kenkyusho, 1973) cannot be satisfied.
According to the invention, since the deodorizing ratio with
respect to the acetic acid is 95% or more, the tolerance
concentration can be satisfied sufficiently. In the case where the
deodorizing ratio of the acetic acid is less than 90%, an
adsorption ability tends to be insufficient.
[0024] In the invention, the air including the carboxylic acid is
not at all limited as to inclusion of another gas component species
as long as a single or composite carboxylic acid species is/are
provided as a part of constituent components in the air, and the
carboxylic acid is 100 ppm or less. A mechanism of the excellent
deodorizing property of the cellulose acetate and/or cellulose is
not clear yet at the present, however, the inventors assume that a
hydrophilic group of the cellulose acetate and/or cellulose and an
acetyl group of a cellulose acetate side chain are related thereto.
That is, a carboxylic group has a hydrophobic part and a
hydrophilic part in a molecule, and it is assumed that the
hydrophobic part thereof is adsorbed to the acetyl group of the
cellulose acetate side chain, and on the other hand, the
hydrophilic part is adsorbed to the cellulose acetate and/or
cellulose via an affinity with a water molecule so as to realize an
excellent deodorizing ability.
[0025] Then, according to the invention, the cellulose acetate
and/or cellulose have/has a particularly high deodorizing ability
with respect to the acetic acid. The reason thereof is presumed
that the acetyl group in the acetic acid and the acetyl group of
the cellulose acetate side chain have stronger affinities. Since
the invention has the deodorizing property for a nonenal as an
aldehyde compound, with a premise that the above-mentioned
mechanism is correct, it is easily presumed that the same
deodorizing ability can be also realized with respect to a
substance in the air having a hydrophobic part and a hydrophilic
part in a molecule. In the case where the deodorizing ratio of the
nonanal is less than 90%, the adsorption ability tends to be
insufficient. Preferably, the deodorizing ratio is 95% and more
[0026] According to the invention, it is important that a moisture
absorbing ratio Aa under a 40.degree. C. temperature and 90% RH
humidity environment is 15.0% or less, and a moisture absorbing
ratio Ab under the 20.degree. C. temperature and 65% RH humidity
environment is more than 2% in terms of appropriate supply of a
moisture absorbing property. That is, as to the moisture absorbing
ratio of the invention, Ab under an average temperature and
humidity environment is more than 2%, and Aa under a high
temperature and high humidity environment is 15.0% or less
equivalent to the standard moisture regain of wool as a natural
fiber, which is 15%, ("Fiber handbook 2001", edited by Nihon Kagaku
Senni Kyokai, published in December 2000), and thus the moisture
absorbing property with little sticky feeling can be obtained.
[0027] Although a desired moisture absorbing property can be
obtained by optionally setting a mixing ratio of the acrylic based
composite fiber according to the invention in a fiber product to be
obtained, preferably the moisture absorbing ratio Aa is 3.0% or
more and 8.0% or less (less than 8.5%, which is the standard
moisture regain of cotton as a representative of a natural fiber).
In the case where it is less than 3.0%, a sufficient moisture
absorbing property tends not to be obtained. Moreover, the moisture
absorbing ratio Ab is preferably more than 2.0% and less than 6.5%.
In the case where Ab is 2.0% or less, the sufficient moisture
absorbing property tends to be hardly obtained. In the case of
realizing the moisture absorbing property of 6.5% or more, content
of the cellulose acetate and/or cellulose needs to be increased, so
that the physical properties such as the fiber strength tend to be
lowered.
[0028] According to the invention, it is important that a moisture
absorbing ratio difference .DELTA.A (=Ab-Aa) at the time of
transfer from the temperature 40% and 90% RH humidity environment
to the 20.degree. C. and 65% RH humidity environment is 1.5 or less
in terms of the supply of a moisture retaining property. That is,
it is important that the moisture absorbing ratio difference
.DELTA.A at the time of transfer from the high temperature and
humidity environment to the average temperature and humidity
environment satisfies 1.5 or less in terms of keeping the moisture
retaining property uninfluenced by environment conditions. In the
case where .DELTA.A is more than 1.5, the moisture retaining
property becomes poor. Therefore, since an appropriate moisture
absorbing property and a moisture retaining property are provided
under the different environment conditions in the invention, the
moisture absorbing and retaining properties uninfluenced by the
environment conditions can be obtained. This means that the
moisture retaining property with little sticky feeling can be
obtained stably even in the case of an external environment change
in the summer or winter, or a high temperature and high humidity
environment in clothes immediately after physical exercises.
[0029] Furthermore, surprisingly, depending on a ratio of the
cellulose acetate and/or cellulose and the acrylonitrile based
polymer, the acrylic based composite fiber of the invention can
obtain the moisture absorbing ratio of 3.5% or more, which is the
standard moisture regain of a triacetate fiber, or the ratio
equivalent to the standard moisture regain of a diacetate fiber,
which is 6.5%, and of wool, which is 15.0% ("Fiberhandbook2001",
edited by Nihon Kagaku Senni Kyokai, published in December 2000).
This means that in the case where the ratio of the cellulose
acetate and/or cellulose and the acrylonitrile based polymer is
same, it tends to be higher than the moisture absorbing ratio
obtained from a mixture of a fiber of the cellulose acetate and/or
the cellulose and a fiber of the acrylonitrile based polymer (for
example, a cloth using a blended fiber, a knitted or woven product
obtained by cross knitting or cross weaving fibers spun
independently, or a pile product obtained directly by tufting from
a sliver without forming a spun yarn, such as a blanket, or the
like). Although a mechanism is not clear at the present, it is
presumed that an increase of interfaces between the cellulose
acetate and/or cellulose and the acrylonitrile based polymer
obtained by the sea island structure is related.
[0030] A fiber composite using the acrylic based composite fiber of
the invention, such as a woven or knitted product and a non-woven
fabric, has a novel feeling, the deodorizing property and the
moisture absorbing and retaining property, which have not been
provided conventionally and it may be a fiber composite including
20% by weight or more of the acrylic based composite fiber of the
invention, preferably 30% or more. Not only being processed in a
spun yarn made of only the acrylic based composite fiber of the
invention, it may be also mixed with a synthetic fiber or a semi
synthetic fiber such as an ordinary acrylic fiber, a polyester
fiber, polyamide fiber and rayon short fiber, and/or cotton, ram
wool, or the like. Moreover, it may be cross knit or cross woven
with a long fiber such as the above-mentioned synthetic fiber or
the semi synthetic fiber and silk. In particular, cloth obtained by
mixing, cross knitting or cross weaving with rayon or ram wool is
provided with a unique feeling, and it is effective in deodorizing
not only an acetic acid odor but also an ammonium odor.
[0031] The fiber composite such as the woven or knitted product or
the non-woven fabric using the acrylic composite fiber according to
the invention has a novel feeling and moisture absorbing and
retaining property, which have not been provided conventionally. It
may be provided as a fiber composite including 20% by weight or
more of the acrylic based composite fiber of the invention,
preferably 30% by weight or more, and further preferably 50% by
weight or more in view of obtainment of a mixing homogeneity.
Moreover, the fiber composite using the fiber of the invention is
not limited to the woven or knitted product and the non-woven
fabric, and it is needless to say that it can be also applied to a
fiber composite such as a pile.
[0032] As end use of the fiber composite using the acrylic based
composite fiber of the invention, clothing applications such as a
sweater, an inner, a shirt, socks, a jersey, and a skirt, bedding
applications such as a blanket and a sheet, interior applications
such as a carpet, a mat, a chair covering and a curtain,
miscellaneous applications such as toiletry goods, an artificial
fur, and a stuffed animal, and an application for handicraft
thread, or the like can be presented.
[0033] The fiber of the invention can be produced for example as
follows. First, an acrylic based composite fiber of the invention
comprising the cellulose acetate and the acrylonitrile based
polymer is obtained, and next, an acrylic based composite fiber of
the invention comprising the cellulose acetate, the cellulose and
the acrylonitrile based polymer is obtained, and furthermore, an
acrylic based composite fiber of the invention comprising the
cellulose and the acrylonitrile based polymer is obtained.
Hereinafter, it will be explained successively.
[0034] A spinning solution made of cellulose acetate, an
acrylonitrile based polymer and a solvent is prepared. The solvent
is not particularly limited as long as it is a solvent capable of
dissolving both the cellulose acetate and the acrylonitrile based
polymer. And any of an inorganic acid based one, an inorganic base
aqueous solution based one, and an organic solvent can be used. As
the solvent, for example, a nitric acid (aqueous solution), a zinc
chloride aqueous solution, a rhodanide aqueous solution, dimethyl
formamide, dimethyl acetamide, dimethyl sulfoxide, ethylene
carbonate, propylene carbonate, .gamma.-butylolactone, acetone, or
the like can be presented.
[0035] As to a method for preparing the spinning solution, it may
be adjusted by agitating and mixing the cellulose acetate, the
acrylonitrile based polymer and the solvent at the same time at a
room temperature, or by heating or cooling as needed, however, it
is also possible to dissolve the cellulose acetate and the
acrylonitrile based polymer independently in the solvent and mix
them.
[0036] In order to obtain the acrylic based composite fiber made of
the cellulose acetate and the acrylonitrile based polymer, having a
fiber structure with the cellulose acetate as the island component
and the acrylonitrile based polymer as the sea component in the
cross section in the direction perpendicular to the fiber axis
according to the invention, a wet spinning method is used, which
provides easy controllability of a coagulation speed of the
spinning solution for forming the recess parts in the fiber cross
section outer circumferential part. Since the coagulation speed by
a dry jet wet spinning method and a dry spinning method other than
the wet spinning method is slow, the recess part formation in the
fiber cross section outer circumferential part becomes
difficult.
[0037] The spinning solution is made into a coagulated filament
using an ordinary spinnerette, and it is drawn to 3 to 7 times
drawing ratio. In the case where the drawing ratio is less than 3
times, mechanical strength of the fiber is lowered, so that
spinability and product durability are lowered. In the case where
the drawing ratio is more than 7 times, process troubles such as+++
a thread break can be easily generated. An oiling process and a
drying process are applied to a drawn thread by an ordinary method.
In this production method of the invention, functional materials,
for example, a fluorine based compound including a pollution
preventive substance, an amine based compound or natural based
substances such as a chitin and a chitosan having an antibacterial
activity, can be applied to a thread before drying and collapsing
processes (a coagulated thread, a washed thread and a drawn
thread).
[0038] The composite fiber made of the cellulose acetate and the
acrylonitrile based polymer of the invention accordingly obtained
becomes an acrylonitrile based composite fiber with a totally novel
feeling, which has not been provided in a conventional cellulose
acetate fiber, a cellulose fiber or an acrylic fiber, and an
excellent spinability, fiber physical property, process ability of
the (yarn) spinning, deodorizing property and moisture retaining
property by having the composite ratio, the ratio of the longest
diameter and the shortest diameter in the fiber cross section, the
size and the number of the recess parts in the fiber cross section
outer circumferential part each at a desired value by changing a
mixing ratio of the components cellulose acetate (A) and
acrylonitrile based polymer (B), a ratio of the longest diameter
and the shortest diameter of a spinnerette hole and a coagulation
condition in spinning.
[0039] Furthermore, by further processing the composite fiber of
the cellulose acetate and the acrylonitrile based polymer of the
invention obtained as mentioned above by a heating process under
alkali, for example, a process with a sodium hydroxide of 12%
concentration at 60.degree. C. for about 30 minutes with a cotton
dyeing machine, a cheese dyeing machine, a hank dyeing machine, or
the like, the cellulose acetate becomes cellulose, so that the
acrylonitrile based composite fiber made of the cellulose acetate,
the cellulose and the acrylonitrile based polymer of the invention,
having the excellent moisture absorbing property, can be obtained.
Moreover, depending on the concentration of the sodium hydroxide or
the processing condition, the acrylonitrile based composite fiber
made of the cellulose and the acrylonitrile based polymer of the
invention can be obtained. Although an alkaline agent to be used is
not particularly limited, it is preferable to use a strong alkaline
such as the sodium hydroxide.
[0040] Moreover, since the moisture absorbing and retaining
performance is improved by the cellulose process, the mixing ratio
of the fiber of invention in an end use product can be lowered, and
the mixing ratio of another functional fiber can be increased.
Therefore a product application for end use can be widened.
Furthermore, it is also effective in terms of widening of the
product application for end use to apply a chemical modification to
a part of the hydroxyl group after the cellulose process so as to
have a cellulose derivative, such as alkyl cellulose, nitro
cellulose, cellulose xanthane, and ion exchange cellulose.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a set of electron microscope photographs of
lateral cross sectional views of each fiber of Examples 1 and 3
according to the invention and Comparative examples 2 and 4.
[0042] FIG. 2 is a set of longitudinal cross sectional views of the
same.
[0043] FIG. 3 is a graph showing evaluation results of moisture
absorbing properties of fibers of Example 9 and Comparative example
7.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] Hereinafter, embodiments of the invention will be explained
further specifically based on representative examples.
[0045] In the examples below, the phrase "% by weight" is indicated
simply as "%".
[0046] (Ratio of the Longest Diameter and the Shortest Diameter in
a Fiber Cross Section and a Number of Recess Parts in a Fiber Cross
Section Outer Circumferential Part)
[0047] After wrapping a fiber bundle in a paraffin resin, and
cutting to a 5 .mu.m thin layer with a microtome, a cut surface was
observed with a transmission type optical microscope (produced by
Nikon Corp., biological microscope E-800), so that a number of the
recess parts of 0.3 .mu.m or more and 3 .mu.m or less width and 0.3
.mu.m or more and 3 .mu.m or less depth in a fiber cross section
outer circumferential part was counted by visual observation.
[0048] (Observation Method for a Sea Island Structure)
[0049] After wrapping a fiber bundle in a two-liquid-type urethane
resin, and cutting to 2 mm length with a safety razor, an ion
plasma etching process was applied to a cut surface with a plasma
reactor (produced by Yamato Kagaku Corp., PR-302). After applying
metal sputtering to a processed surface by an ordinary method, it
was observed with a scanning type electron microscope (produced by
Nihon Denshi Corp., JSM-T20).
[0050] (Single Fiber Strength, Dry Elongation, Knot Strength and
Knot Elongation)
[0051] Methods of 8.7 (tensile strength and a stretching ratio) and
8.8 (knot strength) of JIS L 1015 were used to test a chemical
fiber staple.
[0052] (Feeling Evaluation)
[0053] Dry, tense and soft feelings were evaluated by a sensory
test by touching with hands.
[0054] (Deodorizing Ratio)
[0055] As odor components for a deodorizing evaluation, an
isovaleric acid and an acetic acid as representative odors of a
carboxylic acid, and a nonenal (C.sub.6H.sub.19O) as an aldehyde
compound were selected.
[0056] 1 g of a specimen left still under a 20.degree. C.
temperature and 65% RH humidity environment for 24 hours was sealed
in a 370 mL triangular flask adjusted so as to have a 50 ppm gas
concentration of the isovaleric acid or the acetic acid. After
leaving for 1 hour, the gas concentration in the flask was measured
with a detector tube (Kitagawa type gas detector). For a
comparison, measurement was made in the same manner except that the
specimen was not sealed for obtaining the gas concentration in the
flask after leaving for 1 hour.
[0057] A deodorizing ratio was calculated as a ratio of the gas
concentration with the specimen sealed with respect to the gas
concentration of the comparison.
[0058] In the case of an ammonium as the odor component of the
deodorizing evaluation, it was evaluated in the same manner except
that ammonium gas concentration was adjusted to 110 ppm in the
above-mentioned evaluation method.
[0059] In the case of the nonenal as the odor component of the
deodorizing evaluation, 1 g of a specimen left still under a
20.degree. C. temperature and 65% RH humidity environment for 24
hours was sealed in a 125 mL glass Bayer bottle adjusted so as to
have a 30 ppm gas concentration of the nonenal. After leaving for 2
hours, a nonenal gas concentration was measured with a gas
chromatograph. For a comparison, measurement was made in the same
manner except that the specimen was not sealed for obtaining a
relative deodorizing ratio from a peak area of a gas
chromatography.
[0060] (Moisture Absorbing Ratio)
[0061] After leaving 5 g of a specimen under a 40.degree. C.
temperature and 90% RH humidity environment for 24 hours, it was
collected for measuring a mass and an absolute dry mass thereof. By
the following formula, a moisture absorbing ratio Aa (%) was
calculated. In the same manner, a moisture absorbing ratio Ab of
the same evaluation method except that it is under a 20.degree. C.
temperature and a 65% humidity environment was also calculated by
the following formula.
Moisture absorbing ratio(Aa or Ab)=(mass at the time of
collection-absolute dry mass)/absolute dry mass.times.100
[0062] (Cellulose Acetate Weight Reduction Ratio)
[0063] After soaking a specimen in an acetone and applying a heat
treatment at 70.degree. C. for 20 minutes, it was washed and dried
absolutely for measuring its weight. In the case where cellulose
acetate is included in the specimen, since the cellulose acetate is
extracted by the acetone, the weight is reduced. However, in the
case where the cellulose acetate is changed into cellulose, weight
change does not take place. The weight change before and after the
acetone extracting process was provided as a cellulose acetate
weight reduction ratio.
[0064] Hereinafter, with reference to Examples and Comparative
examples of the invention, characteristics will be compared.
"Spinability, feeling and deodorizing property of Examples 1 to 5
and Comparative examples 1 to 5"
[0065] Spinning solutions were obtained by mixing and dissolving a
cellulose diacetate (A) having a 55.2% average acetylation degree
and an acrylonitrile based polymer (B) (acrylonitrile/vinyl
acetate=93/7 by weight ratio) having a 1.98 reduction viscosity of
a 0.5% dimethyl formamide measurement obtained by aqueous
dispersion polymerization method with solid component ratios shown
in Table 1 in a dimethyl acetamide so as to have a 22% solid
component concentration. The spinning solutions were discharged
into a spinning bath consisting of 56% dimethylacetamide aqueous
solution at 35.degree. C. using a round shape spinarette and drawn
to 6 times while washing with boiling water to prepare drawn
filaments. After that, the filaments were dried and annealed to
prepare fiber with a monofilament fineness of 2.2 dTex.
[0066] Evaluation on the fibers with different solid component
ratios of (A)/(B) in terms of spinability, existence or absence of
a sea island structure, a ratio of the longest diameter and the
shortest diameter of a fiber cross section, a number of recess
parts of 0.3 .mu.m or more and 3 .mu.m or less width and 0.3 .mu.m
or more and 3 .mu.m or less depth generated in a fiber cross
section outer circumferential part, feeling, and a deodorizing
property for a isovaleric acid and an acetic acid, is shown in
Table 1. Moreover, a spinnerette with round shape holes was used
except a case of Example 4 using a spinnerette with elliptical
shape holes that has a 2.0 ratio of a longer axis and a shorter
axis. The deodorizing property with respect to a nonenal was
evaluated for a composite fiber obtained in Example 3 (single fiber
fineness 2.2 dTex) and an acrylic fiber (single fiber fineness 2.2
dTex). Deodorizing ratios were 95% and 38% respectively. Moreover,
moisture absorbing and retaining property evaluation for fibers
used in Examples 1, 3, 5 and Comparative examples 1, 2 is shown in
Table 2.
1 TABLE 1 Ratio of (A)/(B) Existence/ longest solid absence of
diameter and Number of Feeling Deodorizing ratio component sea
island shortest recess Dry Tense Soft Isovaleric Acetic ratio
Spinability structure diameter parts feeling feeling feeling acid
acid Comparative 0/100 Good Absent 2.0 1 Poor Good Good 54 54
example 1 Comparative 5/95 Good Exist 1.5 4 Poor Good Good 73 74
example 2 Example 1 10/90 Good Exist 1.4 5 Slightly Good Good 90 95
good Example 2 15/85 Good Exist 1.4 6 Good Good Good 91 96 Example
3 30/70 Good Exist 1.3 9 Good Good Good 93 98 Example 4 30/70 Good
Exist 2.0 8 Good Good Good 92 97 Comparative 30/70 Good Exist 2.5
10 Good Poor Good 92 97 example 3 Example 5 40/60 Good Exist 1.2 7
Good Good Good 94 98 Comparative 50/50 Poor -- -- -- -- -- -- -- --
example 4 Comparative 100/0 Good Absent 2.0 5 Good Slightly
Slightly 95 98 example 5 good poor
[0067]
2 TABLE 2 (A)/(B) solid Moisture Moisture component absorbing
absorbing ratio ratio Aa (%) ratio Ab (%) .DELTA.A Comparative
0/100 2.4 1.2 1.2 example 1 Comparative 5/95 3.1 1.9 1.2 example 2
Example 1 10/90 4.2 2.8 1.4 Example 3 30/70 6.3 5.0 1.3 Example 5
40/60 7.7 6.3 1.4
[0068] FIG. 1(a) to 1(d) show a lateral cross section of each fiber
obtained by Example 1 and 3, and Comparative examples 2 and 4 by
scanning electron microscope photographs successively. Moreover,
FIG. 2(a) to 2(d) show a vertical cross section of each fiber
corresponding to the same examples by scanning type electron
photographs successively. These fibers were soaked in an acetone at
70.degree. C. for 30 minutes for extracting cellulose diacetate
components in the fibers, and an ion plasma etching process was
applied thereto for 90 seconds for executing a metal spattering on
processed surfaces thereof.
[0069] From these figures, it is understood that a fiber component
of the cellulose diacetate (A) and the acrylonitrile based polymer
(B) constitute a composite fiber having a sea island structure with
the acrylonitrile based polymer (B) providing a sea component and
the cellulose diacetate (A) providing an island component, and the
cellulose diacetate (A) elongates in a fiber direction, partially
communicating with another island component. Furthermore, the
cellulose diacetate (A) component existing on a surface is
extracted into the spinning bath, and it forms recess parts in the
fiber surface according to a difference of coagulation speed
between the cellulose diacetate (A) and the acrylonitrile based
polymer (B).
[0070] Therefore, by changing the solid component ratio (A)/(B) of
the cellulose diacetate (A) and the acrylonitrile based polymer
(B), a volume of the cellulose diacetate (A) existing in the
acrylonitrile based polymer (B), and a size and a number of the
recess parts in the surface of the composite fiber can be
controlled.
[0071] For Example 4 and Comparative examples 1, 3 and 5 in Table
1, evaluation was executed for the fibers obtained in the same
conditions as those of another examples and the comparative
examples except that a hole shape of the spinnelette was changed
from a round type to an elliptical type to prepare the fiber with a
ratio of the longest diameter and the shortest diameter as shown in
Table 1.
[0072] In the case of Comparative example 4 with the (A)/(B) solid
component ratio of 50/50, the fiber cannot be obtained stably
because filament breaks were generated frequently at the spinning
process. Therefore, execution of the evaluation thereof was
impossible as well.
[0073] As it is understood from Table 1, even in the case where the
ratio of the longest diameter and the shortest diameter of the
composite fiber is 2, if the number of the recess parts appearing
on the fiber surface is 4 or less, a dry feeling is poor, and
deodorizing performance with respect to the isovaleric acid and the
acetic acid is low.
[0074] Moreover, as to a feeling evaluation for a commercially
available cellulose diacetate 100% fiber as Comparative example 5
(produced by Mitsubishi Rayon Corp. "Linda" 3.3 dTex), although the
dry feeling and the tense feeling were equivalent to those of the
acrylic based composite fiber of the invention, the soft feeling
was poor compared with the acrylic based composite fiber of the
invention.
[0075] "Process Ability of Yarn Spinning of Examples 1, 3, 5 and
Comparative Example 6"
[0076] Next, for the composite fibers of the above-mentioned
Examples 1, 3, and 5 and Comparative example 6, strength, dry
elongation, knot strength, knot elongation and process ability of
yarn spinning of each single fiber were evaluated. Results are
shown in Table 3. Here, the composite fiber of Comparative example
6 was produced in the same conditions as the Comparative example 4
except that the drawing ratio was changed to 3 times.
[0077] As to the evaluation of the process ability of yarn
spinning, spun yarn of a 2/32 yarn number count were produced by
cutting the composite fibers of Example 1, 3, and 5 and the new
comparative example 6 having the different (A)/(B) solid component
ratios to 51 mm, and mixing with an ordinary acrylic fiber of 2.2
dTex and a 51 mm fiber length at 30/70 mixing ratio.
3TABLE 3 Solid com- ponent Process mixing Single Dry Knot ability
of ratio of fiber elon- Knot elon- yarn A/B strength gation
strength gation Spinning Example 1 10/90 2.3 41.5 2.2 41.0 Good
Example 3 30/70 2.2 41.0 2.0 38.0 Good Example 5 40/60 1.9 32.5 1.8
31.0 Good Comparative 50/50 1.3 26.0 1.4 24.5 Poor example 6
[0078] As it is apparent from Table 3, there is no problem in the
process ability of yarn spinning for Examples 1 and 3. As to the
process ability of yarn spinning with the (A)/(B) solid component
ratio of 40/60 (Example 5), although fly is generated slightly, it
was at a level substantially without a problem. In contrast, in the
case of Comparative example 6 with the (A)/(B) solid component
ratio of 50/50, the spinability is poor (for example the filament
breaks were generated frequently at the spinning process).
Moreover, the process ability of yarn spinning was poor. (Fly is
generated.)
[0079] From this, it was learned that the process ability of yarn
spinning equal to that of an ordinary acrylic fiber spinning
process can be obtained as long as the single fiber strength of the
above-mentioned composite fiber is 1.8 CN/dTex or more, the dry
elongation is 30% or more, the knot strength is 1.8 CN/dTex or more
and the knot elongation is 30% or more. In the case where these
values are not satisfied as in the case of the composite fiber of
Comparative example 6, the process ability of yarn spinning becomes
poor.
[0080] "Deodorizing Property of Each Kind of Spun Yarn with Respect
to an Acetic Acid, an Ammonia and a Nonenal"
[0081] Knitted fabric of a plain stitch organization was knitted
after cutting the composite fiber obtained in Example 3 (single
fiber fineness 2.2 dTex), the acrylic fiber (single fiber fineness
2.2 dTex), rayon (single fiber fineness 1.3 dTex), and ram wool
(64S) each by 51 mm, and mixing by the mixing ratio shown in Table
4, and producing spun yarns of a 1/52 yarn number. On the other
hand, a dyeing liquid was prepared by adding 0.25 g of a dye
(Hodoya Kagaku Corp., Kachiron Blue KGLH), 1 g of an acetic acid,
and 0.25 g of a sodium acetate to 1,000 g of pure water. The dyeing
liquid was heated to 100.degree. C. 50 g of the above-mentioned
knitted fabric was soaked in the dyeing liquid and maintained at
100.degree. C. for 30 minutes. After that, the dyed fabric was
washed with water, dehydrated and dried, and a cation dyeing was
executed. The deodorizing property of these fabrics with respect to
an acetic acid and ammonia were evaluated. Results are shown in
Table 4. The deodorizing property of the knitted fabrics of Example
6 and Comparative example 7 with respect to a nonenal was
evaluated. The deodorizing ratios were 90% and 38%
respectively.
4 TABLE 4 Mixing ratio Fiber Deodorizing obtained ratio (%) in
Acrylic Acetic Example 3 fiber Rayon Wool acid Ammonia Comparative
0 100 0 0 54 54 example 7 Example 6 30 70 0 0 95 79 Example 7 30 40
30 0 97 94 Example 8 30 40 0 30 96 97
[0082] As it is apparent from Table 4, the deodorizing property of
the knitted fabric made of an ordinary acrylic fiber (Comparative
example 7) was not at all satisfactory. In contrast, in the case
that the mixed knitted fabric of the composite fiber of Example 3
and the acrylic fiber, although the deodorizing property of the
fabric has slightly low evaluation in the deodorizing property with
respect to the ammonia, it is no problem in a practical use.
Besides, since it has high deodorizing property evaluation with
respect to the acetic acid, it is easily understandable that the
composite fiber of the invention has the excellent deodorizing
property as well.
[0083] "Moisture Absorbing and Retaining Property of Each Kind of
Spun Yarn"
[0084] Knitted fabric of a plain stitch organization was knitted
after cutting the composite fiber obtained in Example 3 (single
fiber fineness 2.2 dTex) and the acrylic fiber (single fiber
fineness 2.2 dTex) each by 51 mm, and mixing them by a 50/50 mixing
ratio, and producing spun yarns of a 1/52 yarn number. Thereafter,
a knitted fabric with the above-mentioned cation dyeing was
obtained (Example 9). After leaving the knitted fabric and a
knitted fabric made of an ordinary acrylic fiber (Comparative
example 7) in a 20.degree. C. temperature and 65% RH humidity
environment for 4 hours, they were left in a 40.degree. C.
temperature and 90% Rh humidity environment for 24 hours and
successively left in a 20.degree. C. temperature and 65% RH
humidity environment for 24 hours, then, the moisture absorbing and
retaining property of each knitted fabric was evaluated. Results
are shown in FIG. 3.
[0085] Example 9 was superior to the acrylic fiber knitted fabric
(Comparative example 7), and it has a sufficient moisture absorbing
and retaining property in the different environment conditions. The
moisture absorbing property was evaluated for a mixed spun yarn of
a tow of the cellulose diacetate (single fiber fineness 2.2 dTex)
and a tow of the acrylic fiber (single fiber fineness 2.2 dTex) at
15/85 ratio, paralleled by a sliver after leaving it in a
20.degree. C. temperature and 65% RH humidity environment for 24
hours. The moisture absorbing property was 1.8%, which is poorer
than that of Example 9.
[0086] (Moisture Absorbing Property of Examples 10 to 11 and
Comparative Examples 8 to 10)
[0087] To prepare samples of Examples 10 and 11, the fibers
obtained in Examples 3 and 4 were treated with different
concentration of NaOH respectively for 30 minutes at 60.degree. C.
In the case of Comparative examples 8 and 9, the fiber obtained in
Comparative example 1 was treated with different concentration of
NaOH for 30 minutes at 600. In the case of Comparative example 10,
the fiber obtained in Comparative example 2 was treated with NaOH
which using amount is 12 wt % per fiber weight under the same
temperature. Evaluation on the moisture absorbing property, the
weight reduction ratio of the obtained fibers is shown in Table 5.
In the acrylic based composite fibers of Examples 10 and 11, the
cellulose acetate, the cellulose and the acrylic based polymer were
present. Although the cellulose acetate, the cellulose and the
acrylonitrile based polymer were similarly present in the acrylic
based composite fiber in Comparative example 10, satisfactory
performance was not obtained because the cellulose diacetate is
5%.
[0088] (Moisture Absorbing Property of Example 12)
[0089] To prepare the sample of Example 12, the fiber obtained in
Examples 5 was treated with NaOH of which using amount is 14 wt %
per fiber weight for 30 minutes at 80.degree. C. The cellulose
acetate was changed to be the cellulose by an alkaline process so
that the cellulose and the acrylonitrile based polymer were present
in the acrylic based composite fiber. Evaluation on the moisture
absorbing property and the weight reduction ratio of the obtained
fiber is shown in Table 5.
5TABLE 5 Solid Using amount of Cellulose Specimen No. component
NaOH (% with Moisture Moisture acetate weight supplied for mixing
ratio respect to absorbing absorbing reduction NaOH use of A/B
fiber weight) ratio Aa (%) ratio Ab (%) .DELTA.A ratio (%) Example
10 Example 3 30/70 12 8.1 6.8 1.2 30 Example 11 Example 3 30/70 3
4.8 3.2 1.2 11 Example 12 Example 5 40/60 14 13.0 11.6 1.4 40
Comparative Comparative 0/100 3 1.5 1.2 0.3 0 example 8 example 1
Comparative Comparative 0/100 0 1.5 1.2 0.3 0 example 9 example 1
Comparative Comparative 5/95 12 2.5 1.8 0.7 30 example 10 example
2
* * * * *