JPH05148709A - Acrylic modified cross section fiber and its production - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having good water absorption, crispiness and coloring property by subjecting a mixture of acrylonitrile, a vinyl monomer and a sulfo group containing monomer to solution polyierizatmon and subiecting the resultant polymer solution to wet spinning in a coagulation liquid of a specific concentration using a spinning inlet having triangular hole shape. CONSTITUTION:An acrylic copolymer prepared by subjecting a monomer mixture consisting of 80-96wt.% acrylonitrile, <=20wt.% vinyl monomer (e.g. methyl acrylate) and a small amount of sulfo group-containing monomer (e.g. sodium 2-acrylamide-2-methylpropanesulfonate) to solution polymerization is dissolved in dimethylformamide as 23wt.% concentration to give a spinning dope, which is then wet-spun in a solidifying medium having 50-55% solvent concentration using a spinning inlet having triangular hole shape and taken up in 0.8-1.5 ratio of winding rate/discharge line rate to provide the objective modified cross section fiber having openings with 0.2-2mum width and 1-10mum length in the direction of fiber axis on the fiber surface, forming pores toward the central part and having >=3.0g/d single fiber dry strength and >=1.5g/d knotting strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic modified cross-section fiber having streak-shaped openings on the fiber surface.

[0002]

2. Description of the Related Art Acrylic fibers have hitherto been widely used as materials for bedding products, carpets, mats, knit products and the like because they have a wool-like texture and are excellent in bulkiness and color development. However, due to lack of water absorbency and lack of dry texture (sharpness), its use for spring and summer materials has been considerably delayed. In order to make the acrylic fiber absorb water suitable for spring and summer materials, methods such as forming a porous or hollow inside of the fiber have been tried. These techniques include blending different kinds of polymers in the spinning dope and phase separation. Macro voids caused by the phenomenon are left, or C-type, U-type, sheath-core type and further JP-A-57-1
Spinning can be performed using a spinneret having irregularities as disclosed in Japanese Patent No. 67409. However, although the fibers obtained by these methods have satisfactory water absorbency, it cannot be said that the coloring property and the sharpness are sufficiently improved. Especially for modified cross-section fibers, the hole becomes complicated and
It is difficult to obtain fibers below denier.

[0003]

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. An object of the present invention is to provide an acrylic modified cross-section fiber having a streak-shaped opening portion on the surface of the fiber, which is suitable for a material for spring and summer and has excellent water absorbency, sharpness and color development. The crispness referred to here is due to the high friction between fibers. Another object of the present invention is to provide a method for industrially easily producing the above-mentioned acrylic modified cross-section fiber.

[0004]

According to the present invention, a fiber surface is provided with an opening portion having a width of 0.2 to 2 µ and a length of 1 to 10 µ in the axial direction of the fiber, and the opening portion is provided at the center of the fiber. The acrylic-based modified cross-section fiber is characterized in that pores are formed in the opposite direction, and the single fiber dry strength of the fiber is 3.0 g / d or more and the knot strength is 1.5 g / d or more. Further, the production method is a solution polymerization of 80 wt% or more and 96 wt% or less of acrylonitrile and 20 wt% or less of a vinyl-based monomer and a sulfonic acid group-containing monomer, and using a die having a regular triangular shape as a solvent. It is characterized in that wet spinning is carried out in a coagulation bath having a concentration of 50 to 55%, and winding is carried out at a winding speed / discharge linear velocity ratio of 0.8 to 1.5.

The constituent features of the present invention will be described in detail below. The opening portion of the fiber surface of the present invention has a width of 0.2 to 2
The water absorption and water retention are advantageous in the pores having a length of .mu. and a length of 1 to 10 .mu. The reason for this is not clear, but it is considered that the streak-shaped openings are more stable in the water state on the fiber surface and inside the fibers than in ordinary round to elliptical macrovoids. The acrylic modified cross-section fiber of the present invention has a single fiber strength of 3.0 g / d or more and a knot strength of 1.5 g / d or more. Go down.

Next, a method for producing the acrylic modified cross-section fiber of the present invention will be described. In the present invention, 80% by weight
The copolymer of 96% by weight or less of acrylonitrile and 20% by weight or less of a vinyl monomer and a sulfonic acid group-containing monomer is used. Vinyl-based monomers include acrylic acid, methacrylic acid, or their alkyl esters, vinyl acetate, vinyl chloride, vinylidene chloride, sodium allyl sulfonate, sodium methallyl sulfonate, sodium vinyl sulfonate, sodium styrene sulfonate, 2- Examples thereof include sodium acrylamido-2-methylpropane sulfonate. If the content of acrylonitrile is less than 80% by weight, normal physical properties cannot be obtained, and if it exceeds 96% by weight, the color developability is poor. The sulfonic acid group-containing monomer is preferably copolymerized in an amount of 0.3 to 5% by weight. Next, the polymerization method of the copolymer may be any conventionally known polymerization method of vinyl-based monomers, and solution polymerization is a quality,
Cost effective. The solvent used in the present invention,
Examples include dimethylformamide, dimethylacetamide, dimethylsulfoxide, and other inorganic solvents, but organic solvents are preferred to give open areas on the fiber surface.
Prepare the spinning dope at a concentration of ~ 30%.

Next, wet spinning is performed using a spinneret having an equilateral triangular cross section defined in the present invention. The pore area is appropriately selected according to the denier of the fiber. The coagulation bath concentration of the present invention is such that the solvent is 50 to 55% and the coagulant such as water or alcohol is 50 to 45%. If the solvent concentration is less than 50% or more than 55%, the spinnability is poor and the surface of the obtained fiber does not have the openings as in the present invention.

It is taken up when the ratio of winding speed / ejection linear velocity (hereinafter referred to as i value) is 0.8 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 0.8 have a cross-sectional shape close to a circle, and sufficient inter-fiber friction 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 treatments such as drawing with water or washing with water, drawing after drawing, washing with water, or drawing after washing with water, followed by drying and densification, and further mechanical crimping for various higher-order processing. Apply.

[0009]

[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. The water absorption of the present invention is DI
With N-53814, the sharpness (friction between fibers) was measured using an F meter of Rochelled Co. (manufactured by). The coloring property was evaluated by categorizing it with a cationic dye at a bath ratio of 1:50 at 100 ° C. for 60 minutes, and the result was evaluated by the naked eye in five grades (ordinary acrylic fiber was grade 3).

Examples 1 to 3 and Comparative Examples 1 to 3 acrylonitrile / methyl acrylate / 2-acrylamido-2-methylpropanesulfonic acid soda = 92/7
Acrylic copolymer of composition / 1/23 in DMF
A solution dissolved at a concentration of wt% was used as a spinning dope. This was spun into a coagulation bath having an i-value shown in Table 1 through a spinneret having a hole shape of 0.14 mm on a side of 35000 holes and then stretched 5 times in a second bath. Then, it was further washed with water, pre-oiled, pre-dried, post-oiled, crimped, set and post-dried to obtain a 3-denier acrylic modified cross-section fiber.
Table 1 also shows measured values of water absorption, inter-fiber friction, and color development of each fiber.

[0011]

[Table 1]

Further, FIGS. 1 and 2 show photographs showing a cross section and a side surface of the fiber obtained in Example 1, and FIG. 3 shows a photograph showing a cross section of the fiber obtained in Comparative Example 1. In Comparative Example 2, adhesion between fibers was observed. Incidentally, Comparative Example 3 was spun using a spinneret having an ordinary circular hole shape.

[0013]

INDUSTRIAL APPLICABILITY The acrylic modified cross-section fiber of the present invention has streak-like macrovoids on the fiber surface, has excellent water absorption, sharpness, and color developability and is suitable for spring-summer material. ..
Further, the single fiber dry strength is 3.0 g / d or more, and the knot strength is 1.
Since it is 5 g / d or more and has the fiber performance of ordinary acrylic synthetic fibers as it is, the operability in high-order processing is not significantly deteriorated, and it is excellent in high-order processing such as spinning, and easily manufactured industrially. I can.

[0014]

[Brief description of drawings]

FIG. 1 is a photograph showing a cross section of a fiber obtained in Example 1 of the present invention.

FIG. 2 is a photograph showing a side surface of the fiber obtained in Example 1 of the present invention.

FIG. 3 is a photograph showing a cross section of the fiber obtained in Comparative Example 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location D01F 6/40 7199-3B

Claims (2)

[Claims] 1. A fiber surface having a width of 0.2 to 2 μ and a length of 1 to
10 μm has an opening in the axial direction of the fiber, the opening forms a hole toward the center of the fiber, and the single fiber dry strength of the fiber is 3.0 g / d or more; Strength is 1.5g /
Acrylic-based modified cross-section fiber characterized by being d or more. 2. A solution of acrylonitrile in an amount of 80% by weight or more and 96% by weight or less and a vinyl monomer or a sulfonic acid group-containing monomer in an amount of 20% by weight or less is solution-polymerized, and a solvent concentration of 50 is obtained by using a die having an equilateral triangle shape. Wet spinning in a coagulation bath of ~ 55% and the ratio of winding speed / discharge linear speed is 0.8 ~.
A method for producing an acrylic modified cross-section fiber, characterized in that the fiber is collected at 1.5.