JPH11350341A - Treating method for forming communicating pore of hollow fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a functionally excellent fiber by carrying out a communicating pore-forming treatment to suppress reduction of physical strengths, reduce dyeing specks and form communicating pores in a hollow fiber having a specific percentage of hollowness under a specific condition with a dyeing processing at the same time. SOLUTION: In treating a hollow fiber having >=20% percentage of hollowness and formed in fabric such as knitted products or the like in a buffer solution having a temperature equal or higher than the glass transition temperature of the hollow fiber and less than either one of the thermal decomposition- initiating temperature or the thermosoftening temperature, communicating pores are formed from the surface to the hollow part by using the buffer solution having 9.5-11.5 pH and applying repetition of stress within the elastic limit of the hollow fiber along the direction crossing to the longitudinal direction of the hollow fiber, and carrying out a dyeing processing at the same time The size of the communicating pores is preferably 0.2-5 μm wide and 1-50 μm long.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a communicating hole in a hollow fiber, and more particularly, to a method for forming a communicating hole from a surface of a hollow fiber to a hollow portion.

[0002]

2. Description of the Related Art Several methods for forming a communication hole from a fiber surface to a hollow portion have been conventionally known. For example, in the case of a polyester fiber, a method in which a polyester obtained by copolymerizing an organic sulfonic acid compound is melt-spun into a hollow fiber and then subjected to alkali reduction treatment to form a large number of communicating portions (micropores) (Japanese Unexamined Patent Publication No. No. 20319) and a method of forming a large number of communicating portions (micropores) from the fiber surface to the hollow portion by subjecting a polyester hollow fiber to which an organic sulfonate metal salt is added and blended to an alkali reduction treatment (Japanese Patent Publication No. Nos. 61-60188 and JP-B-61-31231) are also known.

However, these methods require alkali reduction in order to form communication holes by removing the organic sulfonic acid compound, and the hollow fibers themselves after the formation of the communication holes are also reduced in alkali. There were problems such as a decrease in strength and tear resistance, causing problems in practical use, and a problem that physical properties such as strength were not constant for each treatment.

Furthermore, if a hollow fiber having a hollow ratio of 20% or more is subjected to alkali treatment, a low-oriented portion along the longitudinal direction of the fiber and / or without the use of the organic sulfonate as described above, and / or A large number of communication holes (microgrooves) can be formed as removal marks of the deformation strain concentration portion (Japanese Patent Application Laid-Open No. 7-26466).

However, in this method, since a strong alkali weight reduction treatment is performed, the fiber strength degradation due to hydrolysis of the polyester is considerably large, and if this is to be suppressed, formation of communication holes becomes insufficient. Further, if the fabric is to be dyed, one more step is required, and it is difficult to carry out stable dyeing with less spots, leading to an increase in cost.

Also, a method of subjecting a core-sheath type composite fiber to an alkali weight reduction treatment to decompose and remove a core polymer to obtain a hollow fiber having a communicating portion (split groove) extending from the fiber surface to the hollow portion in the longitudinal direction of the fiber. (Japanese Unexamined Patent Publication (Kokai) No. 6-173167) is also known, but in this method, the problem of deterioration of fiber strength or insufficient formation of communication holes arises as described above.

Further, when the dyeing step is performed in combination with the step of forming communication holes, it is known that a chemical reaction such as hydrolysis occurs in the dye molecules and the dye is decomposed when a treatment solution for performing the alkali reduction treatment is used. The dyeing of the fabric cannot be performed satisfactorily. As described above, it is extremely difficult to simultaneously perform the formation of the communication hole and the dyeing treatment.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a hollow fiber in which a communication hole having a size and a number sufficient to introduce a liquid having a viscosity of 5 centipoise or more is formed in the hollow fiber. An object of the present invention is to propose a fiber treatment method in which a communication hole is formed while suppressing a decrease in the color density significantly compared with the conventional technology, and the dyeing is simultaneously performed to reduce the occurrence of stain spots.

[0009]

The present inventors have proposed a method described in the specification of Japanese Patent Application No. 10-59650, filed earlier, for solving the above-mentioned problems. That is, according to this method, at the time of forming a communication hole extending from the fiber surface to the hollow portion along the longitudinal direction of the hollow fiber having a hollow ratio of at least 20%, at least the glass transition temperature of the fiber, and A method of repeatedly applying stress within the elastic limit of the fiber in a direction intersecting with the longitudinal direction of the fiber under a temperature equal to or lower than the lower temperature of the thermal decomposition starting temperature or the thermal softening temperature. .

According to the present invention, in this method, even if the processing solution used has a pH in the range of 9.5 to 11.5, if the processing solution is particularly a buffer solution with a weak alkaline agent, Fiber degradation can be suppressed to a practically acceptable range, and the number of times of application of stress within the elastic limit of the fiber applied along the direction intersecting the longitudinal direction of the hollow fiber is significantly reduced, that is, the treatment It has been found that the time can be significantly reduced, and furthermore, the dyeing spots can be greatly reduced without using a leveling agent by simultaneously performing the dyeing during the treatment, and the present invention has been completed. .

That is, according to the present invention, at least 20
% Of the hollow fiber having a hollow ratio of not less than the glass transition temperature of the hollow fiber, and the thermal decomposition start temperature or the heat softening temperature in a buffer solution at a temperature of the lower temperature, whichever is lower, By using a buffer solution having a pH in the range of 9.5 to 11.5, a stress within the elastic limit of the hollow fiber is repeatedly applied along a direction intersecting the longitudinal direction of the hollow fiber to obtain a fiber surface. A method of forming a communicating hole for a hollow fiber, characterized in that a communicating hole from the fiber to the hollow portion is formed, and a dyeing process is performed simultaneously.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
Examples of the hollow fibers used in the present invention include chemical fibers such as rayon and acetate, and synthetic fibers such as polyester and polyamide. In particular, polyester fibers are particularly suitable because there is no need for alkali weight reduction treatment, and therefore, there is no reduction in physical properties such as strength and there is no need for waste liquid treatment after alkali weight reduction treatment.

The polyester as used herein means terephthalic acid as a main dicarboxylic acid component and at least one glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol and the like. Polyester, etc. to the extent that the effects of the present invention are not impaired,
It may be a copolymer obtained by copolymerizing a third component such as isophthalic acid, adipic acid, cyclohexane dimethanol, or a polyester obtained by mixing other kinds of polymers.

Further, these fibers may contain a stabilizer, an antioxidant, a flame retardant, an antistatic agent, a fluorescent whitening agent, a catalyst, a coloring inhibitor, a heat-resistant agent, a coloring agent, inorganic particles, etc., if necessary. It may be.

The hollow fiber can be produced by a conventionally known method.
The method described in Japanese Patent Publication No. 9 can be arbitrarily adopted.

The hollow ratio of the hollow fiber must be at least 20% in order to form a communication hole by the treatment of the present invention and to maintain the necessary physical properties as a fiber, and is preferably 20% or more. It is to use the one in the range of 20 to 60%, and more preferably in the range of 25 to 50%. When the hollow ratio is less than 20%, cracks generated on the surface of the hollow fiber do not grow to the communication hole even if the treatment is performed by applying a temperature and a stress in the above range, or a crack may not be formed at all. Many. Conversely, when the hollow ratio exceeds 60%, on the contrary, the crack may grow too much and the hollow portion of the hollow fiber may be crushed or split, so that the hollow ratio is in the above range. Some are more preferred.

In the present invention, the temperature of the hollow fiber is not less than the glass transition temperature of the hollow fiber and not more than the lower of the thermal decomposition starting temperature or the thermal softening temperature. The treatment is performed by repeatedly applying a stress within the elastic limit of the fiber in a direction intersecting the longitudinal direction of the hollow fiber.

When the treatment temperature is lower than the glass transition temperature of the hollow fiber, the hollow fiber is in a so-called glassy state, so that elastic deformation is unlikely to occur, and even if stress within the elastic limit of the fiber is repeatedly applied. In addition, no cracks are formed on the surface of the fiber, or even if cracks are formed, they hardly grow, and no communication hole is formed. The processing temperature when applying stress to the hollow fiber is
The higher the temperature, the more convenient the cracks occur in a short time, but if the temperature exceeds the thermal decomposition starting temperature of the constituent polymer of the hollow fiber, the hollow fiber itself will deteriorate and the physical properties of the fiber will decrease, and practically, It is not suitable because it may cause inconvenience. Further, when the heat softening temperature of the hollow fiber is lower than the heat decomposition start temperature, even if the treatment temperature is lower than the heat decomposition start temperature, if the heat softening temperature is exceeded, plastic deformation occurs, which is not suitable.

As described above, the appropriate range of the treatment temperature can be determined by the glass transition temperature, the thermal decomposition onset temperature, and the thermal softening temperature of the hollow fiber. For example, in the case of polyethylene terephthalate, the temperature is in the range of about 70 to 170 ° C under the conditions of the wet heat treatment and the aqueous solution treatment, and is in the range of 70 to 240 ° C under the conditions of the dry heat treatment. 140 ° C. range.

Next, the pH of the processing solution in the heat treatment is as follows:
It is preferably in the range of 9.5 to 11.5, more preferably in a buffer of 9.5 to 11.0. If a buffer having the above pH is used, the fiber deterioration can be suppressed to a practically acceptable range. In this case, as the alkaline agent used in the buffer solution, for example, a weak alkali such as sodium carbonate is used, so that the hydrolysis reaction proceeds very gently and fiber deterioration does not occur much. If a strong alkali agent is used as in the conventional alkali weight reduction treatment, the reaction rapidly proceeds, and even if it is partial, fiber deterioration (strength reduction) is not preferred.

In the present invention, since the treatment for repeatedly applying tension is performed in a weakly alkaline treatment solution having a pH in the above-mentioned range, deterioration tends to concentrate on the place where tension is applied, and the hollow portion is crushed. Further, it is possible to avoid problems associated with the conventional alkali treatment, such as a problem that a portion having a very low strength is formed. Further, since the reaction is carried out with a buffer, it is possible to prevent the pH from dropping below an appropriate range due to the progress of the hydrolysis reaction during the treatment.

Further, in the case of a buffer having a pH in the above-mentioned range, a very mild hydrolysis reaction is involved, so that the number of repetitions for applying a stress is greatly reduced, and the processing time can be greatly reduced. . In other words, the treatment can be performed in 1/3 the processing time as compared with the case where the pH is not adjusted.

On the other hand, when the pH of the treatment liquid is higher than this range, for example, as described in JP-A-7-26466, the hydrolysis reaction is so strong that it is not limited to the reaction of the surface layer of the fiber. The fibers reach the inside of the fiber, and as a result, the fiber deteriorates in strength so that it cannot withstand use, and the hollow part may be crushed during the alkali treatment or during the subsequent drying process, heat setting, etc. Yes, and
When the dyeing process is performed simultaneously, the decomposition of the dye is large,
It is difficult to stably perform the dyeing treatment at the same time. On the other hand, if the pH of the treatment liquid is lower than this range, the number of repetitions of applying stress cannot be reduced significantly because no hydrolysis reaction accompanies the fiber surface layer.

The stress repeatedly applied in a direction intersecting the longitudinal direction of the hollow fiber must be within the elastic limit of the fiber. It is not suitable because damage occurs, the hollow portion is crushed, and physical properties such as strength are reduced. Further, the magnitude of the stress required to form the communication hole varies depending on the type of the polymer constituting the hollow fiber, the hollow ratio, the treatment temperature, and the like, and may be appropriately selected according to those conditions.

As a method of applying such a stress,
Any method can be used as long as stress can be repeatedly applied along a direction intersecting with the longitudinal direction of the fiber. For example, a method of repeatedly pressing between nip rollers, a method of repeated calendering, a method called a so-called stone wash method in which a fabric and a stone-like solid material are stirred together in a liquid, and a high-pressure liquid (circular) dyeing machine And a method in which the fibers constituting the fabric are pulled or pushed by a pulling tension when the fabric passes through an ejector portion for circulating the liquid to apply stress by contact with adjacent fibers.

When the stress is repeatedly applied to the hollow fibers, the hollow fibers can be used in any form such as yarn, spun yarn, woven fabric, knitted fabric, and non-woven fabric. What is processed by is suitable.

[0027] By such a repeated stress application process, a communication hole is formed in the hollow fiber from the outer surface of the fiber to the inner surface of the hollow portion. In introducing a liquid of centipoise or more into the hollow portion of the hollow fiber, a width of 0.2 to 5 μm and a length of 1 to 50 μm
Those in the range of m are preferred.

Further, in the method of the present invention, a dye, a dyeing assistant and the like are added to the above-mentioned buffer solution to simultaneously carry out the dyeing treatment. In the case of the polyester fiber, the dye used in the present invention is usually a disperse dye, but in the case of a cationic dyeable polyester fiber, it can be dyed with a cationic dye in addition to the disperse dye. . Among these dyes, dyes having a pH in the range of 9.5 to 11.5 are preferably used. That is, when the pH of the treatment liquid exceeds 11.5, the decomposition of the dye is remarkable, and when the pH is less than 9.5, the hydrolysis reaction does not occur on the fiber surface as described above.

Examples of dyes used in the present invention include Ka
yalon PolyesterBlue BR-S
F, Kayalon Polyester Red H
D-SF, Kayalon Polyester Li
gh Scarlet GS 200, Kayal
on Polyester Yellow BRL-
S, Kayalon Polyester Yellow
w HD-SF, Kayacelon Blue E-
BR, Kayacelon Yellow E-HG
L, Dianix Red RE, Resolin
Violet RL can be exemplified.

[0030]

As described above, in the present invention, the forming process of the communicating hole and the dyeing process are performed simultaneously in the same can body, but the dyeing is performed in a relatively low temperature range of 80 to 9 which is higher than the glass transition temperature.
In contrast to the case where the temperature starts around 0 ° C., the formation of communication holes is caused by the hydrolysis reaction of the fiber surface layer by weak alkali and the repetitive application of stress within the elastic limit. Is formed remarkably.

As described above, when the hydrolysis reaction proceeds, it is considered that the secondary transfer of the dye is progressing in the fiber in the dyeing treatment. Is hydrolyzed to form a porous structure on the fiber surface, so that the transfer of the dye proceeds faster than under acidic conditions, and it is possible to perform stable dyeing with less spots and less staining in a short time without using a leveling agent. Further, in the present invention, since hollow fibers are used, dye transfer proceeds simultaneously from the outer surface of the fibers and the inner surface of the hollow fibers, so that stable dyeing can be performed in this regard.

[0032]

According to the present invention, when forming communication holes having a size and a number sufficient to introduce a liquid of 5 centipoise or more into hollow fibers, the treatment time is significantly longer than when pH is not adjusted. And the communication hole could be formed in a short time. In addition, the dyeing treatment was performed at the same time, and a fabric with less spots could be obtained.

According to the hollow fiber treated by the method of the present invention, a substance having a medicinal effect, a plant fragrance (plant extract, plant protein), a bacterium culture, a wound treatment, etc. Medical and physiological function-imparting substances (animal proteins), electric function-imparting substances (ceramic fine particles) for conductors and magnetic substances, compounds with antibacterial and deodorant properties, compounds with aromatic properties, water absorption A liquid containing a function-imparting substance, such as a compound having moisture absorption properties and a compound having water repellency, in particular, a liquid having a viscosity of 5 centipoise or more can be introduced into the hollow portion of the hollow fiber.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In addition, the measuring method of each characteristic value used in the example and the comparative example is as follows.

(1) Preparation of hollow fiber filaments: Polyethylene terephthalate (polyester) having an intrinsic viscosity of 0.61 is melted, and a hollow fiber undrawn yarn having a hollow ratio of 40% obtained by using a known hollow spinneret. Is stretched to obtain a polyester filament yarn having a hollow cross section (50 denier / 2
0 filament, titanium oxide amount: 0.3% by weight). A cross section was taken with an electron microscope, and the outer radius and the inner radius of the hollow fiber were measured.
It was 15 μm. Further, the glass transition temperature of the hollow fiber was about 70 ° C, the thermal decomposition onset temperature was about 260 ° C (about 170 ° C under wet heat), and the thermal softening temperature was about 230 ° C. The elastic limit stress in the direction perpendicular to the longitudinal direction of one single yarn of this hollow fiber was measured with a micro-compression tester.
g, 1 g at 130 ° C. (the tip of the compressor was circular and the diameter: 26 μm).

(2) Confirmation of presence / absence of communication hole and shape of hollow fiber (Evaluation 1): A cross section of the hollow fiber is photographed with an electron microscope, and the presence or absence of the communication hole is confirmed by an image.

(3) Confirmation of Strength Retention (Evaluation 2): Tensile strength was measured for filaments, and tear strength (pendulum method) was measured for fabrics under the same conditions before and after the stress application treatment. , A strong retention rate was calculated. A case where the retention rate of the strength after the treatment is 90% or more is regarded as a pass.

(4) Whether a liquid having a viscosity of 5 centipoise or more can be introduced from the communication hole (Evaluation 3); dimethacrylate of polyethylene glycol having a polymerization degree of 9, water and potassium persulfate are mixed in a ratio of 30: 69.9995: 0. The yarn or fabric to be evaluated was immersed in a liquid (viscosity at a temperature of 20 ° C .: 10 centipoise) mixed at a temperature of 20 ° C. for 5 days at a temperature of 20 ° C., taken out, and treated with steam at 100 ° C. for 10 minutes. The liquid solidifies. Three places near the communication hole (5 mm intervals) are cut with a cutter knife, and the cross section is observed with an electron microscope. A sample in which the presence of a solid substance in the hollow fiber was confirmed at two or more locations was judged to be acceptable.

(5) Dyeing spots of dyed cloth (Evaluation 4): Dyeing spots were evaluated on the cloth after dyeing by visual judgment. A sample in which no spots were visually observed was judged as acceptable.

Example 1 Hollow multifilament yarn prepared as described above (50 denier / 20 filament)
Used, width: 150 cm, basis weight: 100 g / m, 55
Using a knitted fabric (circular knitted fabric) knitted at the number of courses / inch and 60 wales / inch, scouring and presetting were performed. Subsequently, a buffer solution (pH: 10.5: aqueous solution of sodium carbonate: 0.5 g / liter) and Kay were added using a high-pressure liquid jet dyeing machine.
alon Polyester Blue BR-S
F: treated in a dye bath consisting of 2% owf at a temperature of 130 ° C. for 30 minutes. At this time, the dough is pulled in by the nozzle of the high-pressure liquid jet dyeing machine, and the maximum tension is 3.6 kg.
(1.0 g / loop) at 2-3 second intervals. Observation of an electron microscopic image of the obtained knitted fabric by the method of Evaluation 1 confirmed the presence of a communication hole having a width of 1 μm and a length of 20 μm. Measuring the tear strength of the knit,
The strength retention rate after the treatment according to the method of Evaluation 2 was 92%. In addition, it was confirmed in all three places that solid matter was present in the hollow fiber according to the method of Evaluation 3, and no staining spot was observed by the method of Evaluation 4.

[Comparative Example 1] In Example 1, the pH of the processing solution was set to 7 without adding any additives other than the dye to the solution in the high-pressure jet dyeing machine, and the other conditions were the same as in Example 1. The process was performed. As a result, the average width of the obtained treated cloth was observed by electron microscopic image observation according to the method of Evaluation 1.
The presence of a communication hole having a size of 1 μm and a length of 10 μm was recognized, and the strength retention rate after the treatment according to the method of Evaluation 2 was 94%.
However, the presence of solid matter in the hollow fiber according to the method of Evaluation 3 could not be confirmed at all three places, and the dyed spots were visually observed on the cloth dyed by the method of Evaluation 4.

Comparative Example 2 Processing was performed in the same manner as in Example 1 except that the temperature of the processing solution in the high-pressure dyeing machine was set at 180 ° C. (a temperature exceeding the thermal decomposition starting temperature under wet heat). Was. The obtained treated cloth had an average width of 1 μm and a length of 3 in observation of an electron microscope image by the method of Evaluation 1.
Although the presence of a communication hole having a size of 2 μm was recognized, the hollow portion was partially crushed, and the strength retention rate of the treated fabric was as low as 72%.

[Comparative Example 3] In Example 1, the pull-in tension when the cloth passed through the nozzle of the high-pressure liquid jet dyeing machine was 4.3 kg (1.2 g / loop, stress exceeding the elastic limit stress). The processing was performed in the same manner as in Example 1 except that the processing was repeated at intervals of 2 to 3 seconds. In the obtained treated cloth, the presence of a communication hole having an average width of 1 μm and a length of 30 μm was recognized, but a part of the hollow part was crushed was recognized, and after treatment, The strength retention of the fabric was as low as 76%.

Comparative Example 4 Processing was performed in the same manner as in Example 1 except that an aqueous solution containing caustic soda (pH: 12) was used instead of the buffer solution. As a result, the obtained treated cloth had an average width of 1 μm and a length of:
Although the existence of a communication hole having a size of 40 μm was recognized, the hollow portion was partially crushed, and the strength retention rate of the treated fabric was as low as 64%. Dyeing spots were visually observed on the fabric dyed by the method of Evaluation 4.

Claims (4)

[Claims] 1. A method of buffering a hollow fiber having a hollow ratio of at least 20% at a temperature equal to or higher than the glass transition temperature of the hollow fiber and equal to or lower than a lower temperature of a thermal decomposition initiation temperature or a thermal softening temperature. When processing in a liquid, the p
H is used in the range of 9.5 to 11.5, and a stress within the elastic limit of the hollow fiber is repeatedly applied along a direction intersecting with the longitudinal direction of the hollow fiber to apply a stress from the fiber surface to the hollow portion. The method of forming a communicating hole for a hollow fiber, wherein the communicating hole is formed and the dyeing process is performed simultaneously. 2. The method according to claim 1, wherein the hollow fibers are formed in a fabric form. 3. The method according to claim 2, wherein the fabric is a knitted fabric. 4. The size of the communication hole is 0.2 to 5 μm in width.
The method for forming a communicating hole of a hollow fiber according to any one of claims 1 to 3, wherein m and the length are in the range of 1 to 50 µm.