JPS6011124B2 - Method for producing porous acrylic synthetic fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing porous acrylic synthetic fibers.

More specifically, the present invention relates to a method for producing porous acrylic synthetic fibers containing giant pores and suppressing the presence of micropods. Natural fibers such as wire, wool, and silk account for 20-40%
Synthetic fibers are comfortable to wear because they absorb enough sweat from the human body, but synthetic fibers lack antistatic and moisture absorption properties, and are not suitable for use as products. In terms of value, it is inferior to natural fibers. Especially when it comes to underwear, socks, blankets, and other sleeping bag odors, and sportswear, etc., if they do not have water- or sweat-absorbing properties, sweat emitted from outside the body will condense and adhere to the fiber surface, causing problems such as stickiness, a feeling of underclothing, and a decrease in body temperature regulation function. The discomfort of time cannot be avoided. Various improvements have been made in the past in order to solve the problem of the lack of water and sweat absorption in synthetic fibers.

Most of the improvement methods involve forming micropores in the fibers or forming irregularities on the fiber surface. For example, Tokukan Sho 47-25418 Publication, Mochiko Sho 47-159
01, Japanese Patent Publication No. 48-6649, and Japanese Patent Publication No. 48-665, mild drying conditions are selected so as to leave minute voids or microvoids in the swollen gel tow during the manufacturing process of acrylic fibers. A method for producing porous acrylic fibers is described. Also, Tokkoku Sho 47-25416 Publication, Tokkoku Sho 48-828
No. 5 Publication and Samurai Publication No. 48-8286 disclose that a water-soluble compound is filled into the swollen gel toe during the manufacturing process of acrylic fibers, and the filler is eluted after drying and post-treatment to regenerate voids. Are listed. What the above methods have in common is that they aim to produce porous acrylic fibers in which microvoids originally contained in the swollen gel toe during the production process of acrylic fibers remain in the final product.

The microvoids contained in this swollen gel tow are extremely thermally unstable. For this reason, high-temperature treatment cannot be carried out in the fiber manufacturing process, especially in the drying, shrinking, and crimp-setting steps, resulting in poor heat resistance, shape retention, and crimp stability of the final product, which significantly reduces the commercial value of the product. The voids in the obtained product are extremely small, with a void radius of 10 to 1000 A. Because the fibers contain countless microscopic voids uniformly throughout the fibers, the fibers have many drawbacks, such as a strong elongation of 4.0, poor gloss, and a dull color after dyeing. In addition, due to the uniform presence of countless microscopic voids, the heat resistance of the fibers is poor, making them difficult to use during high-temperature dyeing, steaming, ironing, etc.
Voids disappear, and serious quality deterioration is observed, such as a decrease in water absorption, a change in color, and a decrease in shape retention. Furthermore, attempts to develop water absorbency using such microvoids are not effective because the microvoids tend to exist independently of each other and are difficult to act as channels for absorbing water into the fibers.

That is, a considerable amount of micropoid content is required in order to have a certain degree of water absorption by micropoid, which has the disadvantage of further reducing fiber performance and commercial value. Attempts have been made to improve the texture and dyeability of yarns made of cellulose acetate-acrylic polymers or cellulose acetate-modacrylic copolymers. For example, Japanese Patent Publication No. 31-1989 and Japanese Patent Publication No. 33-12317 describe a method for producing fibers with improved dyeability and texture from a grade yarn stock solution in which cellulose acetate is mixed with a modacrylic copolymer. Are listed. The fibers obtained by this method are sufficiently dense, and no water-absorbing fibers having capillary-like macrovoids inside the fibers have been obtained. In addition, special public service 39-140
No. 2 Publication discloses that an acrylonitrile copolymer containing 85 mol% or more of acrylonitrile and 0.2 mol% or more of a sulfonic acid group or an ethylenically unsaturated monomer having a sulfonic acid group and cellulose acetate are mixed with dimethylformamide or A method is disclosed in which paper yarn liquid containing dimethyl sulfoxide is fed into an aqueous spinning process to produce fibers that are delicate and have dyeability.

As a comparative example, Japanese Patent Publication No. 1402/1983 describes a fiber made of polyacrylonitrile, that is, a homopolymer of acrylonitrile, and cellulose acetate. There is no mention of acroboid formation of dense and dyeable fibers from acrylonitrile copolymers containing acid groups or sulfonic acid groups. A research report with almost the same contents as the above-mentioned invention described in Japanese Patent Publication No. 39-1402y was also published in Industrial Chemistry Magazine 72 Lid No. 5, pp. 1186-11 (1969).

Furthermore, Japanese Patent Publication No. 39-1403 describes a procedure for adding cellulose acetate during polymerization of an Acrylic polymer as a method for mixing cellulose acetate.
If cellulose acetate is added during the polymerization of acrylic polymers, the heat resistance of the woven yarn will decrease due to the denaturation of cellulose acetate, causing trouble during the fiber manufacturing process, and the quality of the product will be insufficient. I can't get anything like that. On the other hand, Hakama Publication No. 44-1196y and Samurai Seki No. 50-1180
No. 27 and Tokusekki No. 50-118026 disclose that cellulose acetate is finely dispersed or cellulose acetate and titanium oxide are finely dispersed in an acrylic polymer or a modacrylic polymer to create an animal hair-like material. However, porous fibers with water absorbing properties such as those obtained in the present invention have not been obtained. Furthermore, the specification of Washigan No. 53-4473 (Special Seki Sho 54-101920), which corresponds to the so-called earlier application of the present application, states that at least 9% by weight of an acrylonitrile-based polymer and a heat-resistant and void-stable material such as cellulose acetate are used. Microporous acrylic fibers are described that have a microporous structure consisting of less than 1% by weight of a curing agent and have improved water absorption. However, Tokubuta Showa 5
No. 3-14473 merely describes a microporous acrylic fiber having a large number of micropores.

There is no description of a fiber that suppresses the presence of microvoids and contains large pores, and a method for producing the same. As mentioned above, conventional methods can only yield microporous acrylic synthetic fibers that have a large number of microvoids. Synthetic fibers cannot be manufactured. The present inventors completed the present invention as a result of intensive research in order to improve these drawbacks. An object of the present invention is to provide a method for producing porous acrylic synthetic fibers having excellent water absorbency and good thread quality.

That is, the present invention provides the following method: 1'small a - Copolymerized with 0.3 to 1.2% by weight of a copolymerizable monomer containing at least 8% by weight of acrylonitrile units and having a sulfonic acid group or a sulfonic acid group. Acrylonitrile copolymer 70-9% by weight and 'b' cellulose acetate 3
An organic solvent solution containing 15 to 35% by weight of such a polymer is prepared, and the organic solvent solution is embossed into a coagulation bath at a temperature of at most 30°C. The fibers in a water-swollen state are first stretched 2.5 to 8 times, and the resulting water-swollen fibers are
The fibers are dried to a moisture content of 1.0% by weight or less at a temperature of 0 to 180°C, and then the satisfactory dried fibers are secondarily stretched to 3 times or less using green heat and wet heat. A is 15〆/ta or less, porosity V is 0.05 to 0.75 〆/ta, and V/A is 1/30 or more, and [21. A method for producing porous acrylic fibers, which comprises forming porous acrylic synthetic fibers containing pores.

According to the present invention, porous acrylic synthetic fibers having the properties described in N above are prepared by combining 2 to 3 parts by weight of cellulose acetate and an acrylonitrile copolymer (hereinafter referred to as
An organic solvent solution containing 15 to 35% by weight of a polymer consisting of 70 to 9 parts by weight (referred to as an acrylic copolymer) is prepared, and in a step t-row, this is poured into a coagulation chamber, and in the process 2 The fibers, which are first stretched 5 to 8 times and are in a water-swollen state due to the process, are heated to a temperature of 100 to 18,000 to a moisture content of 1. It can be produced by drying the film to a weight percent of 100% or less, and then performing secondary stretching of 3 times or less using wet heat according to the process.

The acrylic synthetic fiber according to the present invention is cellulose acetate 2~
3% by weight, preferably 3-2% by weight and 70-9% by weight of the acrylic copolymer, preferably 80-97% by weight.
It becomes more. Although the cellulose acetate used in the present invention is not particularly limited, it usually has an acetylation degree of 48 to 63% and an average polymerization degree of 50 to 300.

The acrylic polymer used in the present invention also contains at least 8% by weight, preferably 85 to 93% by weight, of acrylonitrile units, and 0.3 to 1. It is a product obtained by copolymerizing copolymerizable monomers having a sulfonic acid group or a sulfonic acid group in a weight percent of sulfonic acid groups.

Copolymerizable monomers having sulfonic acid or sulfonic acid groups include, for example, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, and salts thereof, with allyl sulfonic acid or methallyl sulfonic acid and salts thereof being particularly preferred. .

By copolymerizing 0.3 to 1.2% by weight of these, it not only improves the dyeability but also suppresses the deterioration of heat resistance by suppressing the generation of countless microscopic voids, and also suppresses the decrease in heat resistance. Porous fibers with excellent water absorption properties can be obtained. Examples of copolymerizable monomers other than sulfonic acid or sulfonic acid group-containing monomers include alkyl esters of acrylic acid or methacrylic acid such as methyl acrylate, methyl methacrylate, and ethyl acrylate; amides such as acrylamide and methacrylamide; , their N-monosubstituted or NN-disubstituted amides, and vinyl acetate. According to the present invention, the acrylic synthetic fiber is preferably 2 to 30 parts by weight of cellulose acetate.
15 to 35 parts by weight of a polymer consisting of 20 parts by weight and 70 to 9 parts by weight of an acrylic polymer, preferably 80 to 90 parts by weight.
3000 or less, preferably 2500 or less, for example, an organic solvent solution containing 17 to 3% by weight, preferably 17 to 3% by weight,
More preferably, the paper is produced by putting it into a coagulation bath of 20 oo or less.

The spun yarn is then first drawn, dried, and second drawn as described below. If the amounts of cellulose acetate and acrylic polymer are out of the above range, acrylic synthetic fibers with excellent water absorbency and thread strength cannot be obtained.

Furthermore, if the concentration of the polymer is less than 15% by weight, not only the production cost becomes relatively high, but also voids occur and strength and elongation decrease. On the other hand, if it exceeds 35% by weight, the workability and spinnability will decrease due to an increase in viscosity, and the yarn quality will also decrease, so it must be avoided. As the organic solvent for dissolving the polymer, common solvents for cellulose acetate and acrylic polymers can be used, but organic solvents such as dimerthylformamide, dimethylacetamide, dimethyl sulfoxide, and ethylene carbonate are usually used as the solvent. preferred in terms of recovery and purification.

In addition, as the coagulation bath, aqueous solutions of organic solvents such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and ethylene carbonate, and organic solvents such as propyl alcohol and kerosene can be used, but in particular, polymer solvents can be used. An aqueous solution of an organic solvent used for is preferred. Water may be added to the spinning stock solution in an amount that does not cause the spinning stock solution to gel.

This addition of water is effective in adjusting the viscosity of the paper yarn stock solution and suppressing the generation of microvoids in the threads that have been made into threads. Another very interesting point is that the striation-like dispersion form of cellulose acetate in the graded fibers differs depending on the moisture content of the graded yarn stock solution. That is, when the water content in the paper yarn stock solution is increased, the streak-like dispersed form of cellulose acetate becomes more elongated, and when the water content is decreased, it becomes more spherical. Similar results are obtained depending on the viscosity of the paper yarn stock solution. Spinning may be carried out under the same conditions as for ordinary acrylic synthetic fibers, and the fibers are sequentially stretched and washed through several baths. The spinning draft may be set under normal conditions, but a lower one is preferable in order to suppress the generation of microvoids.
Further, the coagulation temperature is preferably lower, for example, 30:00 or less as mentioned above. When the temperature exceeds 30° C., there is a greater tendency for a large number of microvoids to occur, and the yarn quality and quality of the obtained fibers are significantly reduced.

The primary stretching ratio is 2.5 to 8 times, preferably 3 to 6 times. The stretching ratio is 2. If it is less than the needle sound, the strength will be low due to insufficient stretching and orientation of the fibers, and cracks will appear in the fibers, so this should be avoided. On the other hand, if it exceeds 8 times, densification progresses too much and sufficient water absorbency cannot be obtained, resulting in a decrease in operability and must be avoided. In yarns that have been subjected to primary stretching, the pores generated by the linear dispersion of cellulose acetate and the phase separation from the acrylic polymer are usually more clearly defined.

Furthermore, this fiber also contains a large number of microvoids that are originally contained in normal swollen gel toe. These micropoid generally have a small contribution to the water absorbency of the fibers, and are undesirable because they reduce the heat resistance, dyeability, gloss, etc. of the fibers. For this purpose, fibers with a mixture of microvoids and large voids (macropoid, giant pores) are dried to eliminate the micropoid, but the drying conditions in this case are 100 to 180q.
The moisture content is 1 at a temperature of o. (2) By drying to less than % by weight, it is possible to eliminate only microvoids and leave large voids due to phase separation. Drying temperature is 100℃
If it is less than that, the microvoids present in large numbers on the acrylic polymer side will not be completely burned out, resulting in a decrease in the strength and elongation of the yarn, and a decrease in gloss dyeability and heat resistance. Also, 180℃
Exceeding this should be avoided as it will cause hardening and coloring of the fibers. For drying, it is preferable to use a hot roller dryer in which the fibers come into contact with a hot metal surface. or,
If additional drying by blowing hot air at a temperature of 100 to 150 qo is also used, it will be more preferable from the point of view of improving the uniformity of drying. The moisture content of the dried fibers must be kept below 1.0%. If the moisture content exceeds 1.0%, uneven drying of the fibers will occur and a large number of microvoids will be present in some areas, which should be avoided as it will reduce the uniformity of quality such as uneven dyeing, uneven gloss, and uneven strength. Must be. In this drying process, it is also possible to use a torque motor as a drive unit to shrink the material by 5 to 15% at the same time as drying. After drying, the fibers are dried under moist heat to make the phase separation between the acrylic polymer and cellulose acetate more clear, improve water absorption, and provide appropriate fiber physical properties. ~2
It is necessary to perform secondary stretching twice as much.

If the stretching ratio exceeds 3 times, thread breakage will occur, and if the temperature is raised to avoid this, the fibers will stick and fuse together, resulting in a significant drop in water absorption. After secondary stretching, good spinnability is achieved by wet heat shrinkage, oiling, crimp application, crimp setting, etc.
After passing through a post-processing process that imparts performance, it becomes the final product.

As described above, the porous acrylic synthetic fiber produced according to the present invention (hereinafter referred to as the acrylic synthetic fiber of the present invention) contains 70 to 9% by weight of the acrylic copolymer and 30 to 2% by weight of cellulose acetate. Furthermore, the presence of microvoids is suppressed and giant pores are contained.

If the amount of cellulose acetate dispersed in the fiber is less than 2% by weight, the amount of phase separation from the acrylic polymer will be insufficient and the imparting of water absorption will not be sufficient, whereas if it exceeds 3% by weight, phase separation will occur. If the shape is large, the strength and elongation of the fiber, dyeability, gloss, etc. will be reduced, so it must be avoided.

In the acrylic synthetic fiber of the present invention, cellulose acetate is dispersed in the form of streaks in the fiber axis direction, and the ratio of the length of the streaks to the diameter is usually 10 or more.

Further, as described above, the acrylic synthetic fiber of the present invention suppresses the presence of microvoids and contains giant pores.

Therefore, the acrylic synthetic fiber of the present invention mainly contains giant pores, and if we take the ratio (volume ratio) of micro pores to the porosity (V) of the fiber as an example, for example, this ratio is at most 30%.
, preferably 25% or less, more preferably 20% or less,
Particularly preferably, it is 15% or less. Here, micropores refer to pores with a diameter of 2000A or less. Therefore, the water absorbency of the acrylic synthetic fiber of the present invention is substantially achieved by the giant pores.

In other words, it is thought that the reason why the acrylic synthetic fiber of the present invention exhibits excellent water absorption performance is that the pores opened on the surface communicate with the giant pores inside. This means that when the acrylic synthetic fiber of the present invention is observed under a microscope, cellulose acetate is not only dispersed inside the cross section of the fiber;
This is supported by the fact that they are also dispersed in the fiber walls, and the giant pores seen around the dispersed particles are also seen on the fiber surfaces. Furthermore, the acrylic synthetic fiber of the present invention has a pore surface area A of 15 pores/unit or less, preferably 0.02 to 10 pores, and a porosity V of 0.05 to 0.75 pores/unit. , preferably 0.05 to 0.60/V/A, and V/A is 1/30 or more, preferably 1/20 or more.

The surface area of the pores in the fibers was determined by adsorbing nitrogen gas onto the fibers at liquid nitrogen temperature, determining the total surface area of the fibers using the BET equation, and subtracting the surface area of the fiber sheath from that value. The amount of fibers used for measurement was adjusted so that the total surface area measured was 1 or more.

In addition, the porosity V (ground/ground) is determined by measuring the density p (porosity/ground) of a sufficiently dense film having the same composition as the fiber.
And, let the average cross-sectional area including the pores of the entire weave determined by the photographic method be S (ground), and the average cross-sectional area of the page that does not include the fiber pores, determined from the formula ■, be So (ground). This is required by S.

=9. Continued Xp ■However, De is denier.

V = Precious

First, the fibers are woven, weighed, and filled into the cell of a mercury porosimeter, and while pressurizing mercury at room temperature, the pressure and amount of mercury introduced are recorded.

The gap between the hole diameter D (French) and the rib P (PSi) required to fill the hole with mercury is calculated by measuring the Sakaki arm of the hole D = hole 5 and the amount of mercury injected. The diameter D (Buddha) and volume (Earth/Yu) are determined. This draws a pore distribution curve,
The amount of pores with D of 0.2 or less was determined and defined as the fine pore content (clump) per fiber. If the porosity V is less than 0.05/ta, the water absorption of the fiber will not be sufficient, while if it exceeds 0.7/ta, the strength and elongation of the fiber will not only decrease, but also the gloss and dyeability will deteriorate. should be avoided as it also has a negative effect.

In addition, if the surface area A of the pores exceeds 15 mm/h, the number of micro pores increases within the fiber, which not only causes a decrease in strength and elongation.
It must be avoided as it reduces dyeability and heat resistance.

Furthermore, if V/A is less than 1/30, water absorption becomes insufficient, or not only strength and elongation* but also heat resistance, dyeability, etc. decrease. Combining the experimental results of the present inventors, it is found that V/A is 1/
If it is less than 3 degrees, the pores in the fiber become small, and the size of the pores becomes, for example, a radius of less than 1000 A when converted into a sphere, making it impossible to obtain excellent water absorbency and also decreasing strength and elongation.

Examples Hereinafter, the present invention will be explained in detail by showing examples.
Parts and percentages used in the examples are by weight unless otherwise specified.

The water absorption rate was also measured according to DIN-53814.

Example 1 A dimethylformamide (hereinafter abbreviated as DMF) solution with a polymer concentration of 21% in which the ratio of acrylic polymer and cellulose acetate was varied was used as a spinning stock solution and DM was used.
F: water = 65:35 (%), spun in a coagulation bath at 20 o'clock.

The composition of the acrylic polymer is acrylonitrile (hereinafter referred to as A
The ratio is 90.5:9.0:0.5 (%). After the paper yarn, the paper yarn was first stretched 5 times, dried in a 120 oo hot roller dryer until the moisture content became 0.5%, and
Secondary stretching was performed by 1.1 times under moist heat at 0°C. After applying the crimp and setting the crimp, a red fiber was obtained. The results are shown in Table 1. Table 1 shows that huge pores (diameter 200A) account for porosity (V).
(above) is the ratio of Exp-No. 4 fiber is 88.7
Volume %, Exp-No. For fiber No. 5, it was 85.4% by volume.

Example 2 The acrylic polymer used in Example 1 was used as the acrylic polymer to obtain the illusory e fibers* shown in Table 2 by changing various production conditions.

Table 2 Example 3 AN: MA: 8 parts of an acrylic polymer having the composition of sodium allylsulfonate (hereinafter abbreviated as SAS) = 90.2:9.0:0.8 and 2 parts of cellulose acetate Spinning was carried out using the grade yarn stock solution under the conditions shown in the table, and under the paper yarn post-treatment conditions of Example 1, a phantom e fiber was obtained.

However, only for the spinning thread, an aqueous solution of the same solvent as that of the spinning dope was used. The results are shown in Table 3.

The viscosity in the table is the viscosity at 50:00 when measured with a B-type viscometer, and the stability is the gelation resistance at 50:00, the acrylic polymer in the dope, and the acetic acid. This is an evaluation of the dispersion stability of cellulose. Table 3 Example 4 AN:MA:SMAS=90.5:9.0:0.5(%
) 9 parts of acrylic polymer with the composition and 10 parts of cellulose acetate were dissolved so that the DMN polymer concentration was 25%.
The paper was put out into a coagulation bath at 0.degree. C. and subjected to primary stretching at various magnifications.

After the first stretching, drying and post-treatment were performed under the conditions of Example 1 to obtain a fiber of phantom e.

The results are shown in Table 4. Table 4 Example 5 AN:MA:SMAS=92.5:7.0:0.5(%
) A paper yarn stock solution prepared by dissolving 9 parts of a polymer having the composition and 1 part of cellulose acetate in DMF to give a polymer concentration of 25% was mixed with DMF: water = 60:40 (%) at 30%. ℃
A bush is exposed on the skin of
Dry to a moisture content of 0.5% or less using a hot roller dryer with the drying temperature shown in the table, and then perform secondary stretching at 110°C.
After applying the crimp and setting the crimp, red-colored fibers were obtained.

The results are shown in Table 5. Table 5 Example 6 85 parts of a polymer with a composition of AN:MA:SAS=89:10.4:0.6 (%) and 15 parts of cellulose acetate were dissolved in DMF to a polymer concentration of 27%. The prepared yarn stock solution was spun into a coagulation bath at 30° C. with DMF:water 70:30, and the first stretching was performed 5 times.

After the primary stretching, the fibers were dried in a roller dryer at 125° C. to various residual moisture contents, and then 2de fibers were obtained under the post-treatment conditions of Example 2.

The results are shown in Table 6. Table 6 In addition, the proportion of giant pores in the porosity (V) is Exp
-No. 67 fibers, it is 84.7% by volume, and Exp
-No. 85 for 69 fibers. group volume%.

Example 7 The grade yarn stock solution of Example 6 was DM': water 65:35.
The twill yarn was woven into a 2yC coagulation chamber and subjected to 4 times the primary stretching.* After that, it was dried in a 125OO roller dryer with a moisture content of 0.
Dry to 7% or less.

After drying, secondary stretching was performed under the secondary stretching conditions shown in Example 5 to obtain crimped and crimp-set Beni e fibers. The results are shown in Table 7. Table 7 Example 8 AN:MA:SAS=90.5:9.0:0.5(%)
8 parts of an acrylic polymer having the composition and 2 parts of cellulose acetate were dissolved in DMF to give a polymer concentration of 20%, and 2 parts of water was added to the total amount of polymer and DMF of 10 parts. DMF: water = 50:50 (%
), washed with water, stretched 4 times in hot water, dried to a moisture content of 1.0% or less in a roller dryer at 135 pm, and then dried under moist heat at 115 qo. After performing 2-fold secondary stretching, crimping and crimp setting, a fiber of phantom e was obtained.

The fibers are slightly dull and have a porosity of VO. 3rd stream/evening, surface area of pores AI. It is a porous acrylic fiber containing voids with a V/A of 1/3.43 at 03W/N.

The yarn quality has a denier of e, a dry strength of 2.9 mm/de, and a dry elongation of 3.
It was 0.5%. In addition, the wet strength was 2.87 m/de, the green elongation was 31.3%, and there was no decrease in yarn quality even when wet. The features of the porous acrylic synthetic fiber obtained by the present invention are that it has a high water absorption rate and water absorption rate, has excellent wet strength and elongation when water is absorbed, has good gloss, and has a clear color when dyed. There are many things that can be mentioned.

Natural fibers lose their bulkiness and stiffness when wet, but the porous acrylic synthetic fibers of the present invention have a physical water absorption mechanism that sucks water into the pores in the fibers. It does not reduce the bulkiness of the fibers or lower back feel, and has excellent water absorption, water permeability, and moisture permeability. Furthermore, the fibers according to the present invention have excellent anti-pilling properties. Generally, in order to impart anti-pilling properties, reduction of the amount of plastic components in the acrylic polymer, reduction of the polymer molecular weight,
Alternatively, changes in post-processing conditions such as modification of the grade yarn stock solution and stretching/shrinking conditions, such as mixing of low molecular weight polymers, can cause fibers to deteriorate, such as a decrease in strength and elongation, a decrease in heat resistance, and a decrease in spinnability. Although some of the performance and workability are sacrificed, the porous acrylic synthetic fiber according to the present invention has excellent anti-pilling properties without any deterioration in fiber performance or workability. Further, the porous acrylic synthetic fiber according to the present invention has a porosity of 0.05 pores to 0.75 lumens, and is extremely lightweight and heat retaining.

The porous acrylic synthetic fiber of the present invention, which has many excellent properties not found in conventional products, can be used not only for general clothing as inner and outer clothing, but also for sportswear, futon cotton,
Ideal for bedding such as curtains, interior decoration, etc.

Claims (1)

[Scope of Claims] 1 (a) (a) 0.3 to 1.2% by weight of a copolymerizable monomer containing at least 80% by weight of acrylonitrile units and having a sulfonic acid group or a sulfonic acid group; Polymerized acrylonitrile copolymer 70-98% by weight
and (b) preparing an organic solvent solution containing 15 to 35% by weight of a polymer consisting of 30 to 2% by weight of cellulose acetate, (b) spinning the organic solvent solution into a coagulation bath at a temperature of at most 30°C; c) The resulting spun yarn is primarily stretched 2.5 to 8 times, and (d) the resulting water-swollen fiber is 1
It is dried to a moisture content of 1.0% by weight or less at a temperature of 00 to 180°C, and then (e) the obtained dry fiber is secondarily stretched to 3 times or less with moist heat, and (f) the following properties (1) voids are obtained. has a surface area A of 15 m^2/g or less, a porosity V of 0.05 to 0.75 cm^3/g, and a V/A of 1/(30) or more, and (2) microscopic 1. A method for producing porous acrylic synthetic fibers, which comprises forming porous acrylic synthetic fibers in which the presence of voids is suppressed and giant pores are contained. 2. A fiber in which the formation of microvoids is suppressed by spinning an organic solvent solution into a coagulation bath at a temperature of at most 30°C, followed by primary stretching, resulting in a fiber in a water-swollen state and containing distributed giant pores. 2. The method according to claim 1, wherein the microvoids are substantially eliminated by drying, and then secondary stretching is performed to promote a macropore structure. 3. The method according to claim 1, wherein the copolymerizable monomer of the acrylonitrile-based copolymer is sodium methallylsulfonate or sodium allylsulfonate. 4. The method according to claim 1, wherein the primary stretching is 3 to 6 times. 5. The method according to claim 1, wherein the drying is carried out at 105 to 140°C. 6. The method according to claim 1 or 5, wherein the drying is carried out using a hot roller dryer. 7 Dry with a hot roller at 105-140°C and 100-140°C.
The method according to claim 1, which is carried out in combination with hot air at 150°C. 8. The method according to claim 1, wherein the secondary stretching is 1.05 to 2 times.