JPH0931745A - Acrylic continuous filament having new feeling and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain acrylic continuous filaments having a prescribed radius of curvature and new feeling of high crispness and dry touch by spinning acrylic continuous filaments having hollow cross sections by a dry jet-wet spinning in using specific spinning spinnerets and slitting by a false-twisting. SOLUTION: Acrylic continuous filaments having hollow cross sections are obtained by a dry jet-wet spinning in using spinning spinnerets having spinning holes comprising plural arc-shaped slit holes 1 arranged at suitable intervals on a concentric circle. The continuous filaments are slitted by a false-twisting to obtain the objective acrylic continuous filaments having arc-shaped bent flat cross sections having four corners and having <=1μm radius of curvature of at least one corner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic filament having a novel texture and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, acrylic long fibers have been produced at a spinning speed of 200 m / min to 1500 m / min in order to industrially improve productivity. In order to produce such acrylic long fibers at a high speed, a dry-wet spinning method and a wet spinning method using an inorganic solvent having a slow solidification rate are adopted. Therefore, the cross-sectional shape of the fiber will be a smooth curve with no corners even if it has a round cross-section or a modified cross-section. With the cross-sectional shape formed by such smooth curves without corners, slippage between single fibers is unlikely to occur, and it is difficult to obtain a crisp feeling and a dry touch texture.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an acrylic continuous fiber having a corner in the fiber cross section and a novel texture rich in sharpness and dry touch, and a method for producing the same. is there.

[0004]

A first gist of the present invention is as follows.
An acrylic filament having a flat cross-sectional shape that is bent in an arc shape having four corners, and at least one corner has a radius of curvature of 1 μm or less. The second gist is to arrange the concentric circles at intervals. Characterized in that acrylic long fibers having a hollow cross-section spun by a dry-wet spinning method using a spinneret having spinning holes consisting of a plurality of arc-shaped slit holes are split by false twisting. In the manufacturing method.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylonitrile-based polymer constituting the acrylic long fiber of the present invention may be a homopolymer of acrylonitrile, and the vinyl-based monomer copolymerized with acrylonitrile is limited to 40% by weight. It may be an acrylonitrile-based copolymer.

The copolymerizable vinyl monomer includes (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate and hexyl (meth) acrylate. Esters, vinyl chloride, vinyl bromide,
Vinyl halides such as vinylidene chloride, acids such as (meth) acrylic acid, itaconic acid, crotonic acid and salts thereof, maleic imide, phenylmaleimide, (meth) acrylamide, styrene, α-methylstyrene,
Examples thereof include vinyl acetate.

The above-mentioned acrylonitrile polymer can be polymerized by any known method such as aqueous suspension polymerization, emulsion polymerization and solution polymerization, but the amount of unreacted monomer is small and unreacted monomer is unreacted during spinning. Aqueous suspension polymerization and emulsion polymerization that do not contaminate the coagulation bath are preferable, and an aqueous suspension polymerization method that enables continuous production and has high production efficiency is more preferable.

The acrylic long fiber of the present invention has a flat cross-sectional shape bent in an arc shape having four corners, and at least one corner has a radius of curvature of 1 μm or less to obtain the novel texture of the present invention. Is necessary for. When the radius of curvature of all corners exceeds 1 μm, slippage between filaments is unlikely to occur, and it becomes difficult to obtain a crisp feeling or dry touch. In order to obtain a sharper feeling and a dry touch, it is desirable that the radius of curvature of three or more corners be 1 μm or less.

Next, a method for producing an acrylic long fiber having a novel texture of the present invention will be described. In the method for producing an acrylic continuous fiber having a novel texture of the present invention, it is necessary to first spin an acrylic continuous fiber having a hollow cross section, then perform false twisting to split the hollow cross section.

In the production method of the present invention, the spinning solution is
Known washing, dehydration of the acrylonitrile-based polymer described above,
It can be obtained by dissolving it in a solvent that dissolves it via a drying step. Examples of the solvent that dissolves the acrylonitrile-based copolymer include solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, nitric acid aqueous solution, rhodanate salt aqueous solution, and zinc chloride aqueous solution.

In order to obtain an acrylic long fiber having a hollow cross section, a spinneret having a spinning hole composed of a plurality of arcuate slit holes arranged at appropriate intervals on a concentric circle is used as shown in FIG. It is necessary to spin by a dry-wet spinning method. The space between the spinneret and the surface of the coagulating liquid is 3 to 11 mm.
By keeping it at, it becomes easy to obtain a hollow cross section. If it is less than 3 mm, the spinneret is soaked in the coagulating liquid due to the shaking of the coagulating liquid surface, and the yarn is easily broken. On the contrary, if it exceeds 11 mm, the hollow portion is liable to collapse due to the flow of the spinning dope, resulting in a round cross section.

The yarn coagulated in the spinning bath is subsequently subjected to washing, drawing, application of an oil agent, drying, and (if necessary, dry heat drawing) shrinkage relaxation process to become acrylic long fibers having a hollow cross section.

In each step, that is, in the washing step, the solvent content is 1% by weight or less in warm water of 50 to 100 ° C. The stretching step is twice or more in the wet heat state of 80 to 100 ° C., and the drying step is In the shrinkage relaxation step performed at 120 to 180 ° C, it is preferable to perform shrinkage relaxation of 3 to 15% at a temperature of 220 to 280 ° C.

The false twisting process for splitting the acrylic long fibers having a hollow cross section obtained in this way is preferably performed under the following conditions. The yarn feeding speed and the overfeed rate are not particularly limited, but the heater temperature is preferably 150 to 220 ° C. If the temperature is lower than 150 ° C, fluffing occurs during false twisting, and if the temperature is higher than 220 ° C, fusion of the yarn occurs. The twist number is preferably 1500 to 2500 T / m.
If it is 1500 T / m or less, the hollow cross section cannot be split and the desired texture cannot be obtained. Also 2500 T / m
If it is more than the above, fluffing will be severe.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples. (Example 1) A copolymer of 93% by weight of acrylonitrile, 6.5% by weight of vinyl acetate and 0.5% by weight of sodium methallyl sulfonate was dissolved in dimethylacetamide,
A spinning dope having an acrylonitrile copolymer concentration of 25% was prepared.

This spinning dope was kept at 60 ° C., the spinneret having 30 holes shown in FIG. 2 was used to keep the distance between the spinneret and the coagulating liquid surface at 7 mm, and from 70% by weight of dimethylacetamide and 30% by weight of water. After dry-wet spinning into a coagulation bath of 35 ° C., taking out from the coagulation bath at a speed of 50 m / min after forming the yarn, and washing with warm water of 60 ° C. to make residual dimethylacetamide in the filament 0.1% , Stretched 3 times in hot water at 95 ° C, and then uniformly applying an oil agent,
Dry with a heating roll at 0 ° C, and 2 with a hot pin at 200 ° C.
Double dry heat drawing was performed, and 5% shrinkage relaxation was performed with a hot plate at 260 ° C. to obtain an acrylic continuous fiber having a hollow cross section of 150 denier / 30 filaments.

This acrylic long fiber having a hollow cross section was subjected to false twisting at a heater temperature of 180 ° C., a twist number of 1800 T / m, an overfeed rate of 5%, and a winding speed of 80 m / min. Long fibers were obtained.

Observing the acrylic filaments with a micrograph, the radii of curvature of the four corners are 1, 0.
It was 7, 0.3, 0.4 μm.

When this acrylic long fiber was knitted using an 8-gauge cylinder knitting machine and the texture was evaluated, a sharp feel and a dry-touch texture were obtained.

(Comparative Example 1) 30 round holes each having a diameter of 0.1 mm were prepared.
Spinning was performed in the same manner as in Example 1 except that a spinneret having a plurality of spinnerets was used to obtain an acrylic continuous fiber having a round cross section of 150 denier / 30 filaments. This acrylic long fiber was false twisted under the same conditions as in Example 1, but was not split. When this acrylic long fiber subjected to false twisting was knitted, it had a soft and slimy feel.

[0021]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain an acrylic long fiber having a novel texture with a sharp feeling and a dry touch.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a shape of a spinning hole of a spinneret used for producing an acrylic continuous fiber of the present invention.

[Explanation of symbols]

 1 Arc-shaped slit hole

Claims (2)

[Claims] 1. A flat cross-sectional shape bent into an arc having four corners, and at least one corner has a radius of curvature of 1 μm.
Acrylic filaments having a length of m or less. 2. An acrylic long fiber having a hollow cross section, which is spun by a dry-wet spinning method, using a spinneret having a plurality of arcuate slit holes arranged at appropriate intervals on a concentric circle and false twisted. The method for producing an acrylic long fiber according to claim 1, wherein splitting is performed by processing.