JPH0734321A - Acrylic flat yarn and its production - Google Patents

Abstract

PURPOSE:To obtain acrylic flat yarn having an animal hair-like handle suitable for carpet and mat as well as bore and high pile and to attain its industrial and ready production. CONSTITUTION:This acrylic yarn is the one obtained by subjecting a copolymer having 40,000-50,000 molecular weight comprising 84-95wt.% of acrylonitrile, 0.7-3.0wt.% of a sulfonic group-containing vinyl-based monomer and 5-15wt.% of another vinyl-based monomer, to wet spinning and has >=4.5 long diameter/ short diameter ratio in cross section of the yarn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic flat fiber and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, acrylic synthetic fibers are recognized as fibers having the most animal-like texture and luster, and are widely used in the field of imitation fur such as bores and seals assuming natural fur and the field of high pile. .

In recent years, various improvements such as post-processing and addition of various additives to the stock solution for spinning have been carried out in order to bring the texture and luster closer to that of natural animal hair. However, from the viewpoint of spinnability, it is not preferable to add a large amount of the processing agent, and the effect is temporary without temporary durability due to washing and dry cleaning. In order to overcome these drawbacks, some kind of device at the spinning dope stage is preferable. For example, JP-B-56-44163 and JP-B-56-44164 disclose a production method in which a metal compound and a cellulose derivative are added to a spinning dope prepared by dissolving a copolymer of acrylonitrile (hereinafter abbreviated as AN) in an organic solvent. Is listed.
This is to make the texture and luster closer to that of natural animal hair by the synergistic effect of the shielding effect of the metal compound and the phase separation effect of the cellulose derivative with the AN copolymer. Although it is superior in washing resistance and dry cleaning resistance to post-processing, it is necessary to add a large amount of a metal compound, especially a metal compound among cellulose compounds and cellulose derivatives, in order to make gloss equal to that of natural animal hair. However, such a fiber has a drawback that a large amount of a metal compound is exposed on the surface of the fiber, resulting in a marked decrease in spinnability and spinnability.
Acrylic fibers are also widely accepted as materials for bedding, carpets, mats, and knits, in addition to bores and high piles. Recently, animal hair-like texture (flat cross section) is desired for this product as well. Has become. However, the fibers described in JP-B-56-44163 and JP-B-56-44164 are inferior in heat resistance, and various problems occur in the post-processing stage.

Japanese Unexamined Patent Publication Nos. 2-169711 and 2
Japanese Unexamined Patent Publication No. 169712 discloses flat fibers using a copolymer containing 85% by weight or more of acrylonitrile, both of which are inventions relating to dry spinning, and fibers obtained in comparison with the long side / short side ratio of a spinneret. The long axis / short axis ratio of the cross section becomes very small.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have arrived at the present invention as a result of intensive studies in view of the present situation. It is an object of the present invention to provide an acrylic flat fiber having animal hair-like texture for use in not only bores and high piles but also carpets and mats, and a method for easily producing the same.

[0006]

That is, the acrylic flat fiber of the present invention comprises 84 to 95% by weight of acrylonitrile and 0.7 to 3.0 of a sulfonic acid group-containing vinyl monomer.
An acrylic fiber obtained by wet-spinning a copolymer having a molecular weight of 40,000 and 5 to 15% by weight and another vinyl monomer of 5 to 15% by weight, and having a long axis / short axis ratio of a fiber cross section. Is 4.5 or more.

Further, according to the production method of the present invention, 84 to 95% by weight of acrylonitrile and a sulfonic acid group-containing monomer of 0.1.
A copolymer comprising 7 to 3.0% by weight and 5 to 15% by weight of another vinyl-based monomer and having a molecular weight of 40 to 50,000 is polymerized, and then the polymer and dimethylformamide / water = 9.
Polymer concentration of 25% from 6/4 to 94/6 (weight ratio)
A 32% spinning stock solution is prepared and is then spun in a coagulation bath consisting of a dimethylformamide / water system at a spinning draft ratio of 0.6 to 1.5 using a spinneret having a rectangular pore shape.

The acrylonitrile copolymer used in the present invention is copolymerized with 84 to 95% by weight of acrylonitrile and 5 to 15% by weight of another vinyl monomer not containing a sulfonic acid group. If it exceeds 95% by weight, operability such as gelation is deteriorated. If the amount of acrylonitrile is less than 84% by weight, ordinary physical properties and heat resistance of the acrylic fiber cannot be obtained. Further, unless another vinyl monomer containing no sulfonic acid group is copolymerized in an amount of 5% by weight or more, gelation is likely to occur and the operability is deteriorated. On the other hand, if it exceeds 15% by weight, the physical properties and heat resistance of the fiber are deteriorated, and it becomes extremely difficult to industrially manufacture it. This point is well known to those skilled in the art. Vinyl monomers include acrylic acid, methacrylic acid, or their alkyl esters, vinyl acetate,
Vinyl chloride and vinylidene chloride are preferred.

Particularly important in the present invention is 0.7 to 3.0% by weight (preferably 1.
0 to 2.0% by weight) and the concentration of the copolymer in a dimethylformamide (DMF) / water solution, that is, the spinning solution is adjusted to 25 to 32% by weight.
Examples of the sulfonic acid group-containing monomer include methallylsulfonic acid, allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and salts thereof. Among them, the soda salt of methallyl sulfonic acid is introduced in a block manner at the initial stage of the polymerization, so that the copolymer can be made more hydrophilic side, and as a result, the fiber cross section is arranged and good gloss is obtained, which is preferable. Regarding this technical idea, the present inventors have previously proposed Japanese Patent Publication No. 53-9299 and Japanese Patent Publication No. 5-9.
It is based on the inventions described in JP-A-3-9300 and JP-B-53-29734. When the amount of the sulfonic acid group-containing monomer is less than 0.7% by weight, not only the hydrophilicity of the copolymer is insufficient and the fiber has a broken cross section, but also devitrification and dyeability are insufficient. On the other hand, if it exceeds 3.0% by weight, sticking tends to occur in the coagulation process, and it becomes difficult to dye a light color.

The molecular weight (weight average) of the copolymer is 4-5.
It needs to be ten thousand. When it is less than 40,000, the physical properties such as the strength and elongation of the fiber are inferior, while when it exceeds 50,000, the viscosity of the spinning dope becomes high and the concentration cannot be increased, and the flattened shape tends to collapse due to the increase in the amount of desolvation.

The concentration of the copolymer used in the present invention in the spinning dope is adjusted to 25 to 32%. If this concentration is less than 25%, the amount of desolvation when discharged from the die is large, and it becomes difficult to obtain a flattened flat section. On the other hand, if it exceeds 32%, the viscosity becomes high and the spinning dope easily gels, but the number of single yarn breaks during spinning also increases, depending on the molecular weight of the copolymer. The solvent of the spinning dope is DMF / water = 9.
It is necessary to be 6/4 to 94/6 (weight ratio).
When the amount of hydrogenation is less than 4%, macrovoids frequently occur in the solidification step, devitrification occurs, and the shape also collapses. On the other hand, if it exceeds 6%, gelation occurs and spinning becomes difficult.

The above-mentioned copolymer may be polymerized by any of the known vinyl monomer-based polymerization methods, but solution polymerization is preferred in terms of quality and cost.

The die used in the present invention has a rectangular hole shape, and the hole area is appropriately selected according to the denier of the fiber. Under such conditions, if a rectangular die having a long side / short side ratio (A) of 4.5 or more is used, a flat fiber having a long axis / short axis ratio (B) of a fiber cross section satisfying the following formula: Can be produced by wet spinning. 0.8A ≦ B ≦ A If more preferable conditions are selected, flat fibers satisfying the following formula can be manufactured. 0.9A ≦ B ≦ A

In the present invention, a spinning draft (ratio of winding speed / discharge linear velocity, hereinafter referred to as i value) is taken at 0.6 to 1.5. The i-value is an important factor in obtaining the fiber of the present invention. The fibers obtained with an i value of less than 0.6 have a round cross-sectional shape and a good animal hair-like feel cannot be obtained. On the other hand, if it exceeds 1.5, breakage occurs frequently in the coagulation bath, making operation difficult. The coagulated yarn drawn out from the coagulation bath is subjected to various treatments such as washing with water or drawing at the same time as washing with water, or treatment after drawing with water, followed by drying and densification, and further mechanical crimping.

The acrylic fiber produced by the method of the present invention has a flat shape that faithfully reproduces the shape of the die,
The major axis / minor axis ratio (B) is usually about 4.5 to 15. If this ratio is 4.5 or more, preferably 6 to 15,
Good texture of animal hair can be obtained when it is made into textile products such as woven and knitted fabrics and yarns.

[0016]

EXAMPLES Examples of the present invention will be specifically described below, and Comparative Examples will be given to clarify that the fibers of the present invention have excellent properties.

Examples 1 to 4, Comparative Examples 1 to 4 Acrylonitrile (AN) / methyl acrylate (M
A) / sodium methallyl sulfonate (SMAS) = 87.
DMF / water (== 40,000 (number average) acrylic copolymer having a monomer composition of 3 / 11.5 / 0.8 (=
95.5 / 4.5) solution was prepared to the concentration shown in Table 1 to prepare a spinning dope. 0.056 x 0.336 m of each stock solution
m, through a rectangular die with 25,002 holes, 20 ° C, 60
% DMF solution was spun at the i-value shown in Table 1. After spinning, desolvation and primary stretching of 4.0 times were performed in three baths where the DMF concentration decreased sequentially to 30%, 20%, and 15%, and then a 60 ° C washing tank was sufficient. After cleaning, the oil agent was attached in the previous oil tank, and then dried and densified with a 140 ° C. hot roller. After drying, a secondary stretch of 1.3 times is performed by steaming at 117 ° C, and a tension shrinkage of 0.9 times is performed under steaming at 120 ° C, after which oil is attached, crimp is applied, and then dried.
d An acrylic flat fiber having a fiber length of 102 mm was obtained.

The acrylic synthetic fiber thus obtained was passed through a card to obtain a cotton open. A sensory test was performed by 5 judges using open cotton, and those with a texture and gloss similar to those of natural animal hair were marked with "◎", and those with a slight similarity were marked with "○". , And different ones were evaluated as “x” in three stages. In addition, the operability was judged in four stages of "◎", "○", "△", and "×" in consideration of single yarn breakage and roller winding when manufactured under the conditions described in the examples.

[0019]

[Table 1]

Examples 5-6, Comparative Examples 5-8 An acrylic copolymer having the composition ratio AN / MA / SMAS shown in Table 2 and having a molecular weight of 45,000 was added to 28% DMF /
A water (= 95.5 / 4.5) solution was prepared to prepare a spinning dope. 0.056 × 0.336m / m, 10 for each stock solution
Through a 00-hole rectangular die with an i value of 1.0 at 20 ° C, 58
% DMF solution. After spinning, desolvation and stretching were performed, and sufficient washing was performed to apply an oil agent, dry and crimp to finally obtain an acrylic flat fiber of 10d. The acrylic flat fiber thus obtained was passed through a card and opened to evaluate the texture and flatness ratio.

[0021]

[Table 2]

Comparative Examples 9 and 10 Acrylic flat fibers were produced in the same manner as in Example 3 except that the acrylic copolymer had a molecular weight of 34,000.
It was inferior in strength and elongation (Comparative Example 9). An acrylic flat fiber was produced in the same manner as in Example 3 except that the acrylic copolymer had a molecular weight of 55,000 and a polymer concentration of 25%. However, spinning was unstable because the viscosity of the spinning dope was high. In addition, since the amount of desolvation is large, the flat shape is likely to collapse (Comparative Example 1
0).

Example 7 An acrylic flat fiber was produced in the same manner as in Example 3 except that a rectangular die having 0.038 × 0.456 mm and 25,002 holes was used. The cross section of the obtained fiber was uniform with a major axis / minor axis (flatness ratio) of 11.5, and had a better animal hair texture.

[0024]

INDUSTRIAL APPLICABILITY The acrylonitrile copolymer having a specific composition is used according to the production method of the present invention, and DM of the polymer at the time of spinning is used.
The F concentration is adjusted to 25 to 32% and the spinning draft is 0.6 to
By spinning at 1.5, it is possible to industrially easily manufacture an acrylic flat fiber having an animal hair-like texture suitable for high pile, bore, carpet and mat applications.

Claims (3)

[Claims] 1. Acrylonitrile 84 to 95% by weight, sulfonic acid group-containing vinyl monomer 0.7 to 3.0% by weight
And an acrylic fiber obtained by wet-spinning a copolymer having 5 to 15% by weight of another vinyl-based monomer and having a molecular weight of 40 to 50,000, and having a long axis / short axis ratio of 4 in the cross section of the fiber. An acrylic flat fiber characterized by having a value of 0.5 or more. 2. A copolymer comprising 84 to 95% by weight of acrylonitrile, 0.7 to 3.0% by weight of a sulfonic acid group-containing monomer, and 5 to 15% by weight of another vinyl monomer and having a molecular weight of 40 to 50,000. A polymer is polymerized, and then a spinning stock solution having a polymer concentration of 25 to 32% is prepared, which comprises the polymer and dimethylformamide / water = 96/4 to 94/6 (polymerization ratio), and a spinneret having a rectangular hole shape. In a coagulation bath consisting of dimethylformamide / water system, a spinning draft ratio of 0.6
A method for producing an acrylic flat fiber, which comprises spinning at 1.5. 3. A flattened fiber having a long axis / short axis ratio (B) of a fiber cross section of the following formula is obtained by using a rectangular die having a long side / short side ratio (A) of 4.5 or more. The method according to claim 1, which is manufactured. 0.8A ≦ B ≦ A