JP2001181937A - Method for producing acrylic synthetic fiber with excellent crimp removability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plush fabric with good feel of touch and appearance by using such acrylic synthetic fibers that crimps given thereto are easily removable at a polisher treatment temperature lower than ordinary ones, and to provide a method for producing such a plush fabric. SOLUTION: This plush fabric is obtained by using acrylic synthetic fibers which are produced by giving <6 crimps/25 mm fiber length in the spinning process followed by undergoing a relaxation heat treatment, alternatively by combining the above synthetic fibers with shrinkable acrylic synthetic fibers >=15% in percent heat shrinkage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acrylic synthetic fiber having a good crimp-removing property, and to a napped fabric obtained by compounding a synthetic fiber comprising the same.

[0002]

2. Description of the Related Art Animal hair has a two-layer structure consisting of a guard hair (upper hair) portion and a down hair (lower hair) portion, and has excellent characteristics in texture, appearance, and functionality. Used in clothing. The guard hair has a characteristic that it has a straight hair shape without crimping, gives a good hair texture, gives a soft texture, and gives a refreshing glossy appearance. On the other hand, down hair is originally crimped to improve the heat retention and to give a sense of volume. A pile product made of synthetic fiber (hereinafter, referred to as a nap-cloth fabric) that imitates such animal hair as it is is usually guard hair (non-shrinkable fiber).
And down hair (contractile fiber)
The crimps at the tips of the guard hairs are removed by a polisher process (crimping and elongation of the fibers) after forming the nappied fabric, giving an animal hair-like appearance and texture. It is important to leave most of the crimp of the down hair without removing it to give a sense of volume.

[0003] In particular, acrylic synthetic fibers are widely used in the high pile field assuming natural fibers as fibers having animal hair-like feel and luster. However, the general method for producing acrylic synthetic fibers is to perform a heat treatment after crimping, so that the crimped shape given to the fiber is firmly fixed at the time of heat treatment, and a further high-temperature heat history is used in the subsequent dyeing process. Therefore, it was very difficult to remove the crimp in the polishing step. In order to solve these problems, a method of increasing the number of times of polishing or increasing the polishing temperature in the polishing step has been generally used.However, the number of times of polishing is increased more than necessary or the temperature is increased. The removal leads to the removal of down-hair crimps that do not require removal of crimps, and tends to result in products without voluminous feel and luxury. Further, in the case of formation (undyed cotton) or light-color dyeing, there are also appearance problems such as yellowing and deterioration of color development.

[0004] In order to solve these problems, for example, a method disclosed in Japanese Unexamined Patent Application Publication No. Hei 8-260289, which uses undiluted colored fibers as raw cotton for piles, or Japanese Unexamined Patent Application Publication No. 9-78.
As disclosed in Japanese Patent Publication No. 375, 375, efforts to improve the crimp removability, such as a method using flat fibers, have been made, but there are major problems such as limitations on the hue and cross-sectional shape of the fibers. At present, it has not yet reached a sufficient resolution.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned problems of the prior art, and to provide an acrylic resin in which the crimp applied to the fiber is easily removed at a lower polishing temperature than usual. An object of the present invention is to provide a napped fabric having an excellent texture and appearance by using synthetic fibers, and a method for producing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and as a result, after producing a certain number of crimps, The inventors have found that the fibers obtained through the relaxation heat treatment step are extremely excellent in the crimp removability, and have reached the present invention. That is, the present invention relates to a method for producing an acrylic synthetic fiber containing 50% by weight or more of acrylonitrile, when the fiber length is 25 m.
This is a method for producing an acrylic synthetic fiber having excellent crimp-removability, which is obtained through a relaxation heat treatment step after imparting less than 6 crimps per m.

The heat treatment temperature is preferably from 90 to 170 ° C., and the relaxation rate is preferably from 0.6 to 0.95. The heat treatment method is preferably dry heat, saturated steam, pressurized steam or superheated steam.

Further, the present invention is a napped fabric obtained by combining the acrylic synthetic fiber (A) produced by the above method and the shrinkable acrylic synthetic fiber (B) having a boiling water shrinkage of 15% or more. Further, it is preferable that the weight ratio of (A) and (B) in the napped fabric is in the range of (A) / (B) = 5/95 to 95/5.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic synthetic fiber referred to in the present invention is a fiber composed of a copolymer containing acrylonitrile as a main component and containing 50% by weight or more of acrylonitrile. From the viewpoint of sliver strength in the carding step, acrylonitrile is preferably at least 60% by weight, more preferably at least 70% by weight. When the content of acrylonitrile is less than 50% by weight, the texture is away from the animal hair touch, and there is stickiness and lacks volume.

Examples of monomers copolymerizable with acrylonitrile include acrylates, methacrylates, acrylamides, methacrylamides and mono- and dialkyl-substituted products thereof, acrylic acid, methacrylic acid, itaconic acid, and chloride. Vinyl, vinylidene chloride,
Vinyl esters such as vinyl acetate, vinylpyrrolidone, vinylpyridine and alkyl-substituted products thereof, styrenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, methacryloyloxypropylsulfonic acid, and metal salts and amine salts thereof. But,
It is not limited to these. Further, in the present invention, those composed of acrylonitrile, vinyl chloride and / or vinylidene chloride and other polymerizable vinyl monomers are more preferable. In this case, the other polymerizable vinyl monomers include acrylic acid ester and methacrylic acid. Acid esters, acrylamides, methacrylamides and their mono- and dialkyl-substituted products; styrene and α, β-substituted styrenes; vinyl acetate, vinylpyrrolidone, vinylpyridine and their alkyl-substituted products; acrylic acid, methacrylic acid, itaconic acid; Para-styrenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, paramethacryloyloxybenzenesulfonic acid, methacryloyloxypropylsulfonic acid, or metal salts and amine salts thereof can be used.

The above acrylic copolymer can be obtained by a conventional vinyl polymerization method using a compound known as a polymerization initiator, for example, a peroxide compound, an azo compound or various redox compounds.

As a method for spinning these acrylic copolymers, there are spinning methods using a solvent in a spinning solution, such as wet spinning, dry spinning, and semi-dry semi-wet spinning. In general, wet spinning is used. Used. Examples of the solvent used for the spinning dope include organic solvents such as acetone, acetonitrile, dimethylformamide, dimethylacetamide, and dimethylsulfoxide, and rodan salts such as rhodan soda, rhodan potassium, and rhodan ammonium, and inorganic salts such as zinc chloride and lithium chloride. A concentrated solution, sulfuric acid, nitric acid aqueous solution and the like can be mentioned. The spinning solution may be dissolved in an organic solvent having high solubility for the above-mentioned copolymer in consideration of spinnability and process stability, and a known general dissolution method can be used. The spinning solution is preferably spun at a copolymer concentration of 20% by weight or more.

The spinning solution is spun from a spinneret, stretched, dried and heat-treated. As the coagulation bath for wet spinning, water or an aqueous solution in which water and the same solvent used for the spinning dope are mixed can be used.

Hereinafter, the method for producing the acrylic synthetic fiber of the present invention will be described. The stretching method is not particularly limited, and may be stretching in a bath after the coagulation bath (for example, stretching in a warm water bath) or hot stretching in a heating atmosphere of other medium (for example, in a hot air dryer or in a steam box). Stretching, etc.)
For example, a known stretching device can be used, but the stretching ratio is preferably 4 times or more. If the stretching ratio is less than 4 times, the relaxation heat treatment is not sufficiently applied, and furthermore, the physical properties such as strength and elastic modulus are inferior.

[0015] Usually, drying and densification is carried out after the spinning oil is applied, if necessary. The drying temperature is not particularly limited, but is preferably from 100 ° C to 160 ° C, and more preferably from 120 ° C to 150 ° C. If the temperature exceeds 160 ° C., the yellowing of the fiber becomes severe, and if the temperature is lower than 100 ° C., the densification does not proceed sufficiently, and the appearance such as gloss, the physical properties of the fiber, and the crimp removability are inferior.

The term “crimp” as used in the present invention means a crimp obtained by a known method such as a gear crimp method or a stuffing box method, and is not particularly limited. Shrinkage 4-15%, preferably 5
10%. The degree of crimp is obtained by a measuring method represented by JIS-L1074. The number of crimps is calculated by applying a certain load to the fiber and counting the number of peaks and valleys of the crimp.
And is measured according to JIS-L1015. The number of crimps is 6 per 25 mm fiber length
It is good to be less than pieces. If the number is 7 or more, the crimp removability is poor, which is not preferable.

In the present invention, the relaxation heat treatment is performed after crimping is performed by the above method. Examples of the relaxation heat treatment method include dry heat, saturated steam, pressurized steam, and superheated steam. If so, any method may be used.

The relaxation rate is 0.60 times (40%) to 0.95.
It is preferably twice (5%). If it exceeds 0.95 times (less than 5%), the crimp removability is poor, and if it is less than 0.6 times (more than 40%), the fiber properties such as strength and elastic modulus are poor, which is not preferable. Although the relaxation heat treatment temperature depends on the acrylonitrile content of the copolymer and the heat treatment method, it is generally preferably 90 ° C to 170 ° C, more preferably 1 ° C to 170 ° C.
00-160 ° C. If the temperature is lower than 90 ° C., relaxation of 0.9 times or less (10% or more) cannot be obtained, and if the temperature exceeds 170 ° C., problems such as yellowing and sticking of fibers are liable to occur, which is not preferable.

The above-mentioned relaxation heat treatment step is mainly intended to maintain the dimensional stability of the fiber and to maintain the crimped shape. However, in the same relaxation heat treatment method, the higher the acrylonitrile content, the higher the heat resistance. It is necessary to set the heat treatment temperature high in order to improve the properties. For example, the heat treatment temperature in the case of the pressurized steam method is 110 ° C. or more when the acrylonitrile content is 70% or more, 120 ° C. or more when the acrylonitrile content is 80% or more, and when the acrylonitrile content is 90% or more. 125 ° C. or higher is preferred.

The fibers after the relaxation heat treatment can be appropriately subjected to necessary treatments and operations such as oil application and cutting by a known method.

The fineness of the acrylic synthetic fiber used in the present invention is preferably 2 to 40 dtex, and particularly preferably in the range of 5 to 30 dtex, since the characteristics can be easily exhibited. If it is less than 2 dtex, the fibers are too thin, and there is no stiffness to obtain an upright napped fabric. If it exceeds 40 dtex, the fibers are too thick and the texture becomes hard and napped. The fiber cross section is a round cross section, a flat cross section, T type, U type,
V-type, Y-type, C-type, X-type, W-type, dog-bone type, angular cross-section, leaf cross-section, hollow cross-section and the like are not limited, and multi-component fibers such as composite fibers may be used. If necessary, a stabilizer or the like having an effect on rust prevention, coloring prevention, weather resistance and the like may be added to these fibers.

Next, the shrinkable fiber (B) used in the napped fabric of the present invention will be described. (B) has a boiling water shrinkage of 1
Acrylic fibers having 5% or more, preferably 20% or more are good. In this case (B), when the raised fabric is finished using shrinkable fibers having a boiling water shrinkage ratio of less than 15%, it is constituted by a guard hair portion composed of non-shrinkable fibers and the shrinkable fibers. It is not preferable because the pile height of the down hair portion approaches and the step pile effect tends to decrease.

The number of crimps of the shrinkable fiber (B) is 25 m in fiber length
The range is 6 to 17, preferably 8 to 15 per m. The fiber length is in the range of 15 to 64 mm, and more preferably in the range of 18 to 51 mm. If it exceeds 64 mm, the pile heights of the guard hair portion and the down hair portion are close to each other, so that the step pile effect is reduced, and the fiber loss at the time of processing the napped fabric increases. On the other hand, when the length is shorter than 15 mm, sliver breakage in the card process is likely to occur.

The fineness of the shrinkable fiber is preferably from 1 to 12 dtex, more preferably from 2 to 8 dtex. If the ratio is outside this range, sliver breakage occurs in the carding process, and it tends to be difficult to produce practical fibers.

The term “boiling water shrinkage ratio” as used in the present invention refers to the ratio of the shrinkage displacement length to the pre-shrinkage fiber length by comparing the length of shrinked fiber treated under boiling water for 30 minutes with the fiber length before shrinkage. Is shown as a percentage (%).

The weight ratio of the acrylic synthetic fiber (A) obtained by the production method of the present invention to the shrinkable acrylic synthetic fiber (B) having a boiling water shrinkage of 15% or more is (A) /
(B) = 5/95 to 95/5, preferably 20/95
It is in the range of 80 to 80/20. Weight ratio (A) / (B)
= 95/5, the sliver entanglement after passing through the carding process in the process of making the napping fabric is extremely reduced and the sliver strength is reduced, and the sliver is broken at the time of sliver production and in the subsequent knitting process. A problem arises that productivity and operability are remarkably reduced due to the occurrence of the heat generation. On the other hand, when the weight ratio (A) / (B) is less than 5/95, it is not preferable because the animal hair-like texture and appearance are inferior.

After mixing the above (A) and (B), a card sliver is prepared through a card. Next, sliver knitting is performed using a high pile knitting machine. Here, in order to obtain a color effect due to the two-layer structure and a structure similar to natural fur, pre-polishing and pre-shearing are particularly important steps. After uniforming the nap length by shirring, the back of the nap cloth is coated with an acrylate adhesive or the like. At that time, steam is sprayed on the back surface of the nap cloth to shrink the shrinkable fibers in the nap section and complete the shrinking process. Then, at high temperature (14
0-170 ° C) polishing and brushing,
Finishing into a napped fabric by combining medium-temperature (110 to 140 ° C) and low-temperature (80 to 120 ° C) polishing and shearing. The obtained raised fabric is used as the fiber of the raised portion.
20 to 90% by weight of the shrinkable fiber, preferably 25 to 70%
% By weight.

In the present invention, the polishing at a high temperature is 1
70 ° C. or lower is preferred. If the temperature is higher than 170 ° C., the fabric becomes coarse and hard, and hair removal becomes poor, and further down-hair crimps are removed.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. Prior to the description of the examples, a method of preparing and evaluating a napped fabric will be described.

(Preparation Method of Napped Fabric) The fiber obtained in the example is cut into 51 mm to prepare raw cotton, and then dyed at 98 ° C. for 60 minutes at a dye concentration of 2% by weight using an Overmeyer dyeing machine. Was done. 70% by weight of this non-shrinkable fiber and Kanecaron AHD (manufactured by Kaneka Corporation: 4.4 decitex, fiber length 32 mm, 2 mm) as shrinkable fiber
30% by weight (9 crimps per 5 mm) were mixed and knitted with a sliver knitting machine. Next, at 120 ° C., a pre-polishing process (preliminary polishing to remove the directional distortion of the pile) and a pre-shearing process (preliminary cutting of the pile) are performed, and the pile length is adjusted to 17 mm. Back coating was performed on the back surface of the pile with an acrylic ester-based adhesive. afterwards,
Polishing was performed at 155 ° C., followed by brushing, and further, polishing and shearing were combined at 140 ° C., 120 ° C., and 100 ° C. to remove crimps on the nap surface layer to prepare a nap cloth having a pile length of 20 mm.

(Evaluation of crimp-removing property and pile performance) The napped fabric prepared from a visual and sensory viewpoint was subjected to a sensory evaluation by eight judges, and evaluated according to the following criteria. [Crimp removability] ：: The crimp is completely removed. C: The crimp removability was slightly inferior. ×: Inferior crimp removability. [Hand] ：: Soft and animal hair-like. ：: Soft and animal hair-like texture. Δ: Soft feeling, slightly inferior to animal hair-like texture. ▽: Slightly rough feeling, inferior in animal hair-like texture. ×: There is a feeling of roughness, which is considerably inferior to animal hair-like texture. [Yellowness] ：: Same as undyed cotton color. X: The color has changed to yellow as compared with undyed cotton.

Example 1 Acrylonitrile (hereinafter referred to as AN)
2.5 parts by weight of titanium oxide are added to 100 parts by weight of an acrylic copolymer composed of 93% by weight of 93% by weight and 7% by weight of methyl acrylate (hereinafter abbreviated as MA), and dimethylformamide (hereinafter, referred to as DMF) The spinning solution (solid content: 28% by weight) was dissolved in
After passing through a spinneret having a flat orifice of 0 to a coagulation bath with an aqueous solution having a DMF concentration of 65% by weight, followed by water-washing and 6-fold drawing in a water-washing bath, and applying an oil agent to the obtained fiber. Drying was performed at 150 ° C. Next, preheating was performed at 82 ° C. for 2 seconds, four crimps were applied per 25 mm of fiber length by the stuffing box method, and then 0.92 times (8 times) in a pressurized steam atmosphere at 135 ° C.
%) To obtain flat fibers having a single fiber fineness of 16 dtex. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

Example 2 Oxidation was carried out with respect to 100 parts by weight of an acrylic copolymer composed of 80.5% by weight of acrylonitrile, 19% by weight of vinyl chloride and 0.5% by weight of sodium styrenesulfonate (hereinafter abbreviated as 3S). A solution obtained by adding 1 part by weight of titanium and 3 parts by weight of aluminum hydroxide and further dissolving the same in dimethylacetamide (hereinafter referred to as DMAC) was used as a spinning dope (solid concentration: 30% by weight), and a spinneret having a flat orifice having 4000 holes was prepared. Through a coagulation bath with an aqueous solution having a DMAC concentration of 70% by weight,
The fiber was stretched 6 times in a washing bath and a washing bath, and an oil agent was applied to the obtained fiber, followed by drying at 145 ° C. Next, preheating was performed at 82 ° C. for 2 seconds, and four crimps per 25 mm were applied by a stuffing box method.
Under a pressurized steam atmosphere of 0.87 times (13%) to obtain flat fibers having a single fiber fineness of 16 dtex. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

Example 3 1 part by weight of titanium oxide and 3 parts by weight of aluminum hydroxide were added to 100 parts by weight of an acrylic copolymer comprising 70.5% by weight of acrylonitrile, 29% by weight of vinyl chloride and 0.5% by weight of 3S. Parts by weight and further dissolved in DMAC to give a spinning dope (solids concentration 32
% By weight), passed through a spinneret having a flat orifice with 4000 holes, spun into a coagulation bath with an aqueous solution having a DMAC concentration of 70% by weight, and then washed with water and stretched 6 times in a washing bath to obtain After applying oil agent to fiber 1
Drying was performed at 45 ° C. Next, preheating is performed at 82 ° C. for 2 seconds, and after applying 5 crimps per 25 mm by a stuffing box method, a relaxation heat treatment of 0.85 times (15%) is performed in a pressurized steam atmosphere at 120 ° C. Thus, flat fibers having a single fiber fineness of 16 dtex were obtained. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

Example 4 1 part by weight of titanium oxide and 3 parts by weight of aluminum hydroxide were used for 100 parts by weight of an acrylic copolymer composed of 62% by weight of acrylonitrile, 37% by weight of vinyl chloride and 1.0% by weight of 3S. Was further dissolved in DMAC to obtain a spinning dope (solid content: 32% by weight), which was passed through a spinneret having a flat orifice having 4,000 holes, and then spun into a coagulation bath with an aqueous solution having a DMAC concentration of 69% by weight. Then, wash with water and wash tub 6
Draw twice and apply an oil agent to the obtained fiber.
Drying was performed at 0 ° C. Next, preheating was performed at 82 ° C. for 2 seconds, and five crimps per 25 mm were applied by a stuffing box method. Subsequently, a relaxation heat treatment of 0.83 times (17%) was performed in a pressurized steam atmosphere at 120 ° C. Thus, flat fibers having a single fiber fineness of 16 dtex were obtained. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

Example 5 A flat fiber having a single fiber fineness of 16 dtex was produced in the same manner as in Example 4 except that a relaxation heat treatment of 0.80 times (20%) was performed in a superheated steam atmosphere at 180 ° C. Obtained. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

Example 6 1% by weight of titanium oxide was added to an acrylic copolymer comprising 50% by weight of acrylonitrile, 48.5% by weight of vinyl chloride and 1.5% by weight of 3S.
And 3% by weight of aluminum hydroxide, and DMAC
The solution dissolved in the above solution was used as a spinning solution (solid content: 33% by weight), which was spun through a spinneret having a flat orifice having 4,000 holes into a coagulation bath with an aqueous solution having a DMAC concentration of 70% by weight, and then washed with water and washed with water. The fiber was stretched 6 times in a bath, an oil agent was applied to the obtained fiber, and the fiber was dried at 130 ° C. Next, preheating was performed at 82 ° C. for 2 seconds. After applying 5 crimps per 25 mm by a stuffing box method, a relaxation heat treatment of 0.90 times (10%) was performed in a dry heat atmosphere at 150 ° C. Thus, flat fibers having a single fiber fineness of 16 dtex were obtained. Crimping according to the above conditions,
Dyeing and preparation of a napped fabric were performed, and the napped fabric was evaluated.

Example 7 Flat fibers having a single fiber fineness of 16 dtex were obtained in the same manner as in Example 6, except that a relaxation heat treatment of 0.85 times (15%) was performed in a saturated steam atmosphere at 97 ° C. Was. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

(Comparative Example 1) The number of crimps per 25 mm is 7
Single fiber fineness 16
Decitex flat fibers were obtained. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

(Comparative Example 2) The number of crimps per 25 mm was 7
Single fiber fineness 16 in the same manner as in Example 2 except that
Decitex flat fibers were obtained. Dyeing and preparation of a napped fabric were performed according to the above conditions, and the napped fabric was evaluated.

(Comparative Example 3) The number of crimps per 25 mm is 8
Single fiber fineness 16 in the same manner as in Example 3 except that
Decitex flat fibers were obtained. Dyeing and napping fabrics were prepared and evaluated according to the above conditions.

(Comparative Example 4) The number of crimps per 25 mm is 6
Single fiber fineness 16
Decitex flat fibers were obtained. Dyeing and napping fabrics were prepared and evaluated according to the above conditions.

(Comparative Example 5) The number of crimps per 25 mm was 8
Single fiber fineness 16
Decitex flat fibers were obtained. Dyeing and napping fabrics were prepared and evaluated according to the above conditions.

Example 8 The flat fibers obtained in Example 3 were not dyed, and Kanecaron AHP (produced, 4.4 decitex, fiber length 32 mm, crimp number 9 per 25 mm) was used as a contractile fiber. A standing fabric was prepared according to the conditions described above and evaluated.

(Comparative Example 6) The flat fibers obtained in Comparative Example 3 were not dyed, and Kanecaron AHP (produced: 4.4 decitex, fiber length: 32 mm, number of crimps per 25 mm: 9) was used as a contractile fiber. Using the above conditions, a napped fabric was prepared and evaluated.

(Comparative Example 7) Polishing at 180 ° C followed by brushing was performed, and further, at 160 ° C, 140 ° C,
A raised fabric was prepared and evaluated in the same manner as in Comparative Example 6, except that polishing and shearing were combined at 120 ° C. Table 1 shows the results of evaluation of the napped fabric of the examples and the comparative examples.

[0047]

[Table 1] From the results of Examples 1 to 8 and Comparative Examples 1 to 7, it can be seen that when the number of crimps is within the range of the present invention, the crimp removability is good, and the texture of the obtained napped fabric is also good. In addition, as shown in Example 8 and Comparative Examples 6 and 7, when the number of crimps is out of the range of the present invention, the removal of the crimp can be improved by increasing the polisher temperature. (Yellowness) is inferior.

[0048]

EFFECT OF THE INVENTION By using the acrylic synthetic fiber of the present invention, crimp can be easily removed by a polisher treatment at a temperature lower than usual, and a napped fabric having an excellent texture and appearance can be obtained. It can be widely used for toys (stuffed toys), interior goods, etc.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4L036 MA04 PA18 PA19 RA04 4L048 AA16 AA37 AA46 AA47 AA50 AA55 AA56 BA23 BA30 DA00 DA01 DA15 DA19

Claims (5)

[Claims] 1. A method for producing an acrylic synthetic fiber containing 50% by weight or more of acrylonitrile, wherein the fiber length is 25%.
A method for producing an acrylic synthetic fiber having excellent crimp-removing properties, comprising applying a relaxation heat treatment after applying less than 6 crimps per mm. 2. The method according to claim 1, wherein the relaxation heat treatment is performed at a temperature of 90 to 170 ° C. and a relaxation rate of 0.6 to 0.95. 3. The acrylic having excellent crimp-removability according to claim 1, wherein the relaxation heat treatment uses at least one method selected from the group consisting of dry heat, saturated steam, pressurized steam and superheated steam. Method for producing synthetic fibers. 4. An acrylic synthetic fiber (A) obtained by the method according to any one of claims 1 to 3, having a boiling water shrinkage of 15%.
% Napped fabric which is composited (knitted) with at least 30% of shrinkable acrylic synthetic fiber (B). 5. The weight ratio of (A) and (B) is (A) /
The raised fabric according to claim 4, wherein (B) is in the range of 5/95 to 95/5.