JPH05132814A - Acrylonitrile-based filament bundle - Google Patents

Abstract

PURPOSE:To produce the subject filament bundle having high quality in high productivity at a low cost by wet-spinning an acrylonitrile-based polymer and setting the tensile modulus of the coagulated fiber within a specific range. CONSTITUTION:The objective acrylonitrile-based filament bundle is produced by wet-spinning an acrylonitrile-based polymer under a condition to get a coagulated fiber having a tensile modulus adjusted to about 2.0-3.0g/d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low cost acrylonitrile filament bundle.

[0002]

BACKGROUND OF THE INVENTION Acrylonitrile fiber has a long history,
A variety of materials having various characteristics and forms depending on the use and purpose have been developed. Among them, further functionalization and high added value are desired not only for clothing but also for industrial materials, and the importance of filaments (long fibers) as fiber bundles is increasing. .. On the other hand, acrylonitrile-based fibers as raw materials are required to be low in price except for a very limited number of special ones, and it is indispensable to improve production technology for filaments in order to reduce manufacturing cost.

Conventionally, filaments are generally produced by a dry spinning method or a dry-wet spinning method in order to avoid the breakage of single fibers, fluff and the like from being mixed in the fiber bundle. However, these spinning methods are more difficult than the wet spinning method because it is difficult to increase the density of nozzle holes due to the spinning method and the initial investment in manufacturing equipment is large. Is difficult to reduce.

In general, in the production of low-cost acrylonitrile fiber, the wet spinning method is adopted as the spinning method because it is advantageous in increasing the density of nozzle holes and requires relatively little investment in manufacturing equipment. Has been done.
However, the obtained fiber bundle generally has many single fiber breaks and fluffs, and is not treated as a filament. Although a special example, a filament bundle produced by a wet spinning method is also known. Examples of these include filament bundles obtained by reducing the process passing speed of fiber bundles, or the periphery of spinning nozzles, for the purpose of suppressing rapid deformation (stretching) during spinning process and resistance of running fiber bundles in liquid. In order to maintain a uniform coagulation bath state, the hole density of the nozzle may be lowered to obtain the same. However, at the same time, all of these are accompanied by a decrease in spinning productivity, and it can be said that they are still insufficient from the viewpoint of low-cost filament bundles.

Despite a lot of research being carried out in the past, the filament bundle has a satisfactory quality with suppressed filament breaks and fluffs, and at the same time is highly productive and supplied at low cost. The current situation is that nothing that can be done has been found.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention diligently studied such conventional techniques for eliminating single fiber breakage / fluffing of acrylonitrile fiber by wet spinning and improving stability of fiber production. As a result, the present invention has been completed. That is, an object of the present invention is to provide an acrylonitrile-based filament bundle that has high productivity, low cost, and high quality.

[0007]

The gist of the present invention is to obtain an acrylonitrile-based filament obtained by wet spinning an acrylonitrile-based polymer so that the coagulated fiber has a tensile elastic modulus of about 2.0 to 3.0 g / d. It's a bunch.

In the present invention, the acrylonitrile polymer comprises acrylonitrile, or acrylonitrile and at least one other monomer (comonomer) copolymerizable therewith. Here, as the comonomer, for example,
(Meth) acrylic acid and its esters, vinyl acetate, vinyl propionate, (meth) acrylamide, diacetone acrylamide, N-hydroxymethyl acrylamide, itaconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, methacryloyl Examples thereof include nitrile, styrene and α-methylstyrene. Of these, hydrophilic and water-soluble comonomers are preferable. The degree of polymerization of such an acrylonitrile-based polymer has an intrinsic viscosity [η]
Is preferably 0.8 or more.

The filament bundle of the present invention is obtained by a wet spinning method. Here, the present inventors impair the tensile elastic modulus of the coagulated fiber, which is a process yarn in wet spinning, and the quality of the final fiber bundle obtained by post-treating this fiber as a filament bundle such as single fiber breaks and fluffs. I found a relationship with the phenomenon. That is, the tensile modulus of the coagulated fiber is about 2.0.
In the case of 3.0 g / d (d = denier is based on the weight of the polymer content in the coagulated fiber), the fiber bundle obtained by further post-treating the coagulated fiber by stretching, washing, drying and the like is ,
It has very few single fiber breaks and fluffs, and has stable high quality even though it is obtained by a wet spinning method.

When the tensile modulus of the coagulated fiber is less than about 2.0 g / d, uneven elongation is caused in the initial stage of the spinning process such as in the coagulating liquid, and the fineness of the obtained fiber bundle is extremely uneven. Become. Further, the change in drawability in each spinning step becomes remarkable, and breakage of single fiber is induced, which makes stable continuous filament bundle spinning difficult. On the other hand, the tensile elastic modulus is about 3.
If it exceeds 0 g / d, fiber breakage in the coagulation bath and deterioration of the drawability in the subsequent step are caused, and a fiber bundle satisfying all of the mechanical properties, quality and stability of production cannot be obtained. The tensile modulus of the coagulated fiber depends on the degree of polymerization of the raw material polymer and the type and content of the comonomer when added, and further the concentration of the spinning solution, coagulation conditions (coagulation liquid composition, temperature, coagulation draft, etc.) and coagulated fiber. Determined by factors such as fineness.

A production example of the acrylonitrile-based filament bundle of the present invention will be described. The method for polymerizing the acrylonitrile polymer of the present invention is not limited to any known method such as solution polymerization and slurry polymerization. As the solvent used for spinning, known organic and inorganic solvents can be used.

In the present invention, an acrylonitrile polymer solution is spun by a wet spinning method according to a known method,
Coagulation, stretching (in bath or in air and bath) and dry densification. The drawing in the bath may be carried out directly on the coagulated fiber, or may be carried out after drawing the coagulated fiber in the air in advance. Stretching in the bath is usually performed in a stretching bath at 50 to 98 ° C. once or twice in multiple stages, and water washing may be performed before, after, or in the middle, but the present invention is not limited thereto. By these operations, the coagulated fiber is preferably stretched about 3 times or more by the time the stretching in the bath is completed.

The fiber after the drawing in the bath and the washing can be treated with an oil agent and dried by any known method. For example, the drying can be carried out by a plurality of heating rollers (or heating drums) or hot air. Although it is good, a method using a heating roller at about 100 to 200 ° C. is preferable in consideration of the drying speed, the facility simplicity, and the like. If necessary, before or after drying, the fibers may be stretched with a heating roller or pressure steam at a higher temperature.

[0014]

The present invention will be specifically described with reference to the following examples. "%" Represents% by weight. (A) "Tensile elastic modulus of coagulated fiber": After the coagulated fiber bundle is collected, it is immediately pulled by tensilon at a sample length (grabbing interval) of 10 cm and a pulling speed of 10 cm / min in an atmosphere of a temperature of 23 ° C and a humidity of 50%. Perform the test. The elastic modulus is expressed by the following formula: denier (d; coagulated fiber bundle 900 of coagulated fiber bundle)
The weight occupied by the polymer per 0 m) was calculated and shown in g / d. d = 9000 × f × Qp / V f: number of filaments, Qp: discharge amount of polymer per nozzle hole (g / min), V: solidified fiber take-up speed (m
/ Min) (b) “Intrinsic viscosity of polymer [η]”: measured with a dimethylformamide solution at 25 ° C.

Example 1 and Comparative Example 1 Acrylonitrile 93%, diacetone acrylamide 7
% Of the copolymer having an intrinsic viscosity [η] of 1.3 was dissolved in dimethylacetamide at a copolymer concentration of 23% to prepare a spinning dope, and the results are shown in Table 1 using a nozzle having a pore diameter of 0.08 mmφ and 12000 holes. Coagulation draft 0.8 (coagulation draft =
Wet spinning was performed at a coagulated fiber take-up speed / spinning solution discharge linear velocity). Table 1 shows the tensile modulus of elasticity of the obtained coagulated fiber bundle. The coagulated fiber was washed and desolvated while being drawn 5 times in boiling water, immersed in an oil solution, and dried and densified with a heating roller at about 130 ° C. to obtain a single fiber denier 2.0.
A fiber bundle of 12,000 filaments was obtained. During spinning, single fiber breakage and fluff generated in the dried fiber bundle running immediately before the winder were visually measured, and the number of fluff generated per 100 m of the fiber bundle is shown in Table 1 as the fluff frequency.

[0016]

[Table 1]

Comparative Example 2 A copolymer containing 93% acrylonitrile and 7% methyl acrylate and having an intrinsic viscosity [η] of 1.8 was used as a copolymer concentration 2
It is dissolved in dimethylacetamide at 0% to prepare a spinning stock solution,
Coagulation bath conditions are dimethylacetamide concentration 65%, temperature 3
Spinning was performed in the same manner as in Example 1 except that the temperature was 5 ° C. At this time, the tensile elastic modulus of the coagulated fiber bundle was 4.3 g / d. When single fiber breakage and fluff were measured in the same manner as in the example, the fluff frequency was 8.4.

Example 2 90% acrylonitrile and 10% methacrylic acid 2-hydroxyethyl ester and having an intrinsic viscosity [η] of 1.8.
The copolymer of Example 1 was dissolved in dimethylacetamide at a copolymer concentration of 20% to prepare a spinning stock solution, and the pore size was 0.075 mmφ, 1
Wet spinning was performed using a 2000-hole nozzle and discharging into a coagulation bath having a dimethylacetamide concentration of 65% and a temperature of 35 ° C. At this time, the coagulation draft was changed by increasing / decreasing the stock solution discharge amount, and then spinning was performed in the same manner as in the examples. The tensile modulus of the coagulated fiber bundle and the fluff frequency immediately before the winder were measured under each coagulation draft condition, and the results are shown in Table 2.

[0019]

[Table 2]

Claims (1)

[Claims] 1. An acrylonitrile-based filament bundle obtained by subjecting an acrylonitrile-based polymer to wet spinning to obtain a coagulated fiber having a tensile elastic modulus of about 2.0 to 3.0 g / d.