JPS6018332B2 - Manufacturing method of acrylic hollow fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing acrylic hollow fibers from a copolymer containing acrylonitrile as a main component.

An object of the present invention is to provide a method for producing acrylic hollow fibers with high hollowness, heat retention, and feathery feel with good ironability. Conventionally, the following two methods are known as representative methods for manufacturing hollow fibers. Namely, 1) using a spinneret with a special structure, introducing an inert gas into the center of the fibers to form hollow fibers, and 2) introducing volatile substances, blowing agents, etc. into the bran stock solution to coagulate it. This is a method in which hollow fibers are formed by foaming in the process or drawing process. However, in the former method (2), the structure of the spinneret is complicated, making it difficult to stably obtain hollow fibers.

In addition, in the latter method (2), the volatile substance and foaming agent expand, and when deaerated, cracks or scratches occur along the surface, making the surface uneven, and the resulting fibers are extremely weak and have poor spinnability. It was bad. The inventors of the present invention have conducted intensive research to improve the drawbacks of the conventional methods as described above, and as a result, they have arrived at the present invention and have achieved the intended purpose.

That is, in the present invention, when spinning a spinning stock solution of an acrylic copolymer containing 85 mol% or more of acrylonitrile into sheath-core paper yarn, the copolymer concentration in the stock solution supplied to the core section is combined with the sheath section. 15 to 80 of the copolymer concentration in the yarn stock solution
%, and the combined ratio of the spinning dope to the warp dope to be combined with the sheath part is 20 to 80% by volume.

According to the method of the present invention, the spinnability is good, the obtained hollow fiber has a dense structure on the surface layer, the inside is formed by a group of micro pores, has a high hollow ratio, and has excellent heat retention and feather It is a hollow fiber with a rich texture and good texture and dyeability. The configuration, embodiments, and effects of the present invention will be explained in more detail below.

The acrylic copolymer used in the present invention is 85 mol%
The above acrylonitrile and other copolymerizable pinyl copolymers are copolymerized by a conventional method.

The polymerization method for these polymers may be any commonly known polymerization method for vinyl monomers. Usually, aqueous suspension polymerization, emulsion polymerization, solution polymerization, etc. using a redox catalyst are employed, but there are no limitations depending on the polymerization method and polymerization conditions. Other copolymerizable monomers used in the present invention include acrylamide, N-methylacrylamide, maleimide, methallyl alcohol,
-Hydroxyethyl methacrylate, acrylic acid, methyl acrylate, vinyl chloride, vinylidene chloride, etc.

However, the monomers that can be used are not limited to these. The above-defined copolymers include inorganic acids such as nitric acid and sulfuric acid, which are conventionally known as solvents for acrylic copolymers, inorganic salts such as zinc chloride and rhodan soda, dimethylformamide, dimethylacetamide, It is dissolved in an organic compound such as dimethyl sulfoxide, ethylene carbonate, etc., or a mixture of one or more of these to form a stock solution.

Note that a solution of a solution polymer polymerized in a solvent in which the copolymer of the present invention can be dissolved may be used as it is as a spinning dope.

The paper yarn stock solution obtained as described above is supplied to the sheath, while
A portion is diluted with the same solvent to lower the copolymer concentration and supplied to the core.

These two types of continuous thread stock solutions are green-spun or dry-spun into a sheath-core shape through a normal sheath-core thread nozzle to form a coagulated thread body, and then washed with water, stretched, dried, and heat-relaxed. give As a result, a hollow fiber having a dense surface layer and a large number of micropores inside can be obtained. The sheath of the acrylic hollow fiber obtained by the method of the present invention has the same degree of density, strength and elongation, dyeability, and other suitable physical properties as the so-called regular acrylic fiber obtained by the ordinary yarn spinning method. It has no cracks or scratches and has good spinnability.

On the other hand, the core becomes an aggregate of micropores protected by a dense surface layer and has a high hollowness ratio. In the present invention, it is not clear what mechanism causes the hollow part to form, but the sheath part, which has a high copolymer concentration, coagulates first and forms a strong outer shell, while the core part has a large amount of solvent. It is presumed that a sponge-like hollow part is formed by coagulation and solvent removal, and this becomes a hollow fiber protected from external forces by a sheath.

Therefore, if the ratio of the neck is small, the protective effect of the sheath is small, and thread breakage and collapse of the sheath occur during stretching.
Moreover, if the ratio of the sheath part is large, the characteristics as a hollow fiber will be reduced, which is not preferable.

Similarly, if the copolymer concentration in the core is not much different from that in the sheath, it is difficult to form hollow fibers, and if the concentration is too low, yarn breakage occurs frequently during drawing.

Therefore, the concentration of the copolymer in the bulk yarn stock solution fed to the core is in the range of 15% to 80%, particularly preferably 20% to 65%, of the copolymer concentration in the sheath.

Further, the supply ratio of the spinning dope to the core is in the range of 20% to 80%, preferably 25% to 75%, in terms of volume ratio of the spinning dope to the saddle. In other words, hollow fibers can be obtained by changing the supply ratio of the shark thread stock solution that is combined with both parts of the sheath and core and the difference in the polymer concentration between the two stock solutions, but if you want to obtain hollow fibers more stably, the above supply ratio of the core stock solution. When the ratio of the core stock solution is small, it is preferable to lower the copolymer concentration in the core stock solution, and when the supply ratio of the core stock solution is large, it is preferable to increase the copolymer concentration in the core stock solution. Note that the hollowness ratio defined in the present invention means that the hollow fiber is made of Cevron Green B (E.I.
．． 2% o. w. f. The dyed fiber is cut into rings, and the ratio of the area of the hollow part (the dyed part) to the area of the outer periphery of the fiber.

The area is measured by projecting a cross-sectional photograph of the sliced fiber onto a sheet of paper of uniform thickness, and calculating the weight ratio of the space according to the following formula. V=[W,/(W, upper W2)]×10
0 W,: Weight of space W2: Weight of non-space Next, embodiments of the present invention will be described.

Example 1 Using a combination of ammonium persulfate and acidic sodium sulfite as a polymerization catalyst, polymerization was carried out at 55° C. for 5 hours in water adjusted to pH 2.5 with sulfuric acid to obtain the following polymer.

A: Acrylonitrile, (hereinafter referred to as AN)/methyl acrylate (hereinafter referred to as MA)/sodium methacrylsulfonate (hereinafter referred to as M) = 89/10.5 no 0.58: AN/acrylamide (hereinafter referred to as AA)/MA/MB/=84 /9.0/6.
5/0.5C: AN/3-hydroxyethyl methacrylate (hereinafter referred to as 8H)/vinyl chloride (hereinafter referred to as VC) = 90/7
/4D:AN/maleimide (hereinafter referred to as MI)/MS=94/
6.5/0.5 These four types of copolymers were dissolved in a 65% by weight aqueous nitric acid solution at 0° C. to the concentrations shown in Table 1 to prepare a shark silk stock solution.

Next, these paper yarn stock solutions were combined as shown in Table 1, and the warp stock solutions of each composition were mixed at -2°C using a sheath-core paper thread cap with 50 holes and a pore diameter of 0.08. It was discharged into a nitric acid aqueous solution at a discharge ratio of 1:1 and solidified, and after washing with water, it was poured into boiling water for 8 hours.
After stretching it twice and then drying it in hot air at 130℃,
A heat relaxation treatment was carried out in 11 piston steam to obtain a fiber of about 3 denier.

In Inventions 1, 2, and 3, hollow fibers having a suitable hollowness ratio of about 30% were obtained.

In addition, this hollow fiber had suitable strength and elongation for practical use in clothing and other applications, and had good mating and dyeability.
In the comparative example, only a material with a significantly low hollowness ratio was obtained, and the effect as a hollow fiber was poor. Table 1 Example 2 Acrylic copolymers A, B, C, D polymerized in Example 1
was dissolved in a 65% by weight aqueous nitric acid solution at 0°C to a concentration shown in Table 2 to prepare the yarn stock solution.

Next, these stock solutions were combined as shown in Table 2, and the spinning stock solution consisting of each combination was placed in a nitric acid aqueous solution containing % fibers at -2°C using a sheath-core spinneret with a pore size of 0.08 and 50 holes. It was discharged and solidified at the discharge ratio shown in the table, and after washing with water, it was stretched 8 times in boiling water, dried in a hot air dryer at 130°C, and then 110q
The fibers were heat-relaxed in a steam bath of about 3 denier to obtain hollow fibers of about 3 deniers.

In the example of the present invention, a hollow fiber with a hollow ratio of 32% and good texture and dyeability was obtained, but in Comparative Examples 3 and 6, which had a large amount of stock solution supplied to the core, thread breakage was severe during the drawing process. However, no fibers with commercial value were obtained.

Moreover, in Comparative Examples 4 and 5, in which the amount of the V-supplied stock solution supplied to the core was small, the hollowness ratio became small, and the performance and effect as hollow fibers were poor. Table 2 Example 3 80q of acrylic copolymers A and B polymerized in Example 1
A stock solution of bush yarn was prepared by dissolving it in an aqueous solution of dimethylformamide with a diameter of 0.
．． 08 side, 50% through a sheath-core spinneret with 300 holes
Extruded into dimethylformamide aqueous solution and coagulated,
Washed with water.

Next, it was stretched 8 times in boiling water, dried with hot air at 130 oo, and then heat-relaxed with steam at 12,000 oo, giving a shape of about 3
Denier hollow fibers were obtained. The obtained hollow fibers had a dense surface layer, a hollowness ratio of 24 to 25%, and good dyeability.

Claims (1)

[Claims] 1 A copolymer in the spinning stock solution that supplies the copolymer concentration in the spinning stock solution supplied to the core to the sheath part when sheath-core spinning a spinning stock solution of an acrylic copolymer containing 85 mol% or more of acrylonitrile. A method for producing acrylic hollow fibers, characterized in that the concentration of the spinning dope is 15 to 80% and the supply volume ratio of the spinning dope to the spinning dope supplied to the sheath is 20 to 80%.