JP3048448B2 - Acrylonitrile filament bundle - Google Patents

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]

2. Description of the Related Art Acrylonitrile fibers have a long history,
Those having various characteristics and forms according to applications and purposes have been developed. Among them, further functionalization and higher 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 materials are required to be inexpensive except for very limited specialty fibers, and it is indispensable to improve production technology for filaments in order to reduce production costs.

Conventionally, filaments are generally manufactured by a dry spinning method or a dry-wet spinning method in order to prevent single fiber breakage and fluff from being mixed into the fiber bundle. However, compared to the wet spinning method, these spinning methods make it more difficult to increase the density of nozzle holes due to the spinning method and increase the initial investment in manufacturing equipment. Is difficult to reduce.

In general, wet spinning is adopted as a spinning method for the production of low-cost acrylonitrile-based fibers, because it is advantageous in increasing the density of nozzle holes and requires relatively little investment in production equipment. Have been.
However, the obtained fiber bundle generally has many single fiber breaks and fluff, and is not treated as a filament. As a special example, a bundle of filaments formed by a wet spinning method is also known. Examples of these are filament bundles obtained by reducing the fiber bundle passing through the process, or the vicinity of the spinning nozzle, for the purpose of rapid deformation (drawing) during the spinning process and for suppressing the resistance of the running fiber bundle in the liquid. In order to maintain a uniform coagulation bath state, there are those obtained by lowering the hole density of the nozzle. However, at the same time, all of these are accompanied by a decrease in spinning productivity, and are still insufficient from the viewpoint of low cost filament bundles.

[0005] Despite a great deal of research, a filament bundle with single fiber breakage and fluff is suppressed to a satisfactory quality, and at the same time, supplied at high productivity and at low cost. At present, what can be done has not been found yet.

[0006]

SUMMARY OF THE INVENTION The present inventors have intensively studied, with respect to such a conventional technique, the elimination of broken single fibers and fluff of acrylonitrile-based fibers by wet spinning and the improvement of the 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 which has high productivity, low cost, and high quality.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an acrylonitrile-based filament obtained by wet spinning an acrylonitrile-based polymer and setting the tensile modulus of the coagulated fiber to about 2.0 to 3.0 g / d. A bunch.

In the present invention, the acrylonitrile-based polymer comprises acrylonitrile or one or more kinds of acrylonitrile and another 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-hydroxymethylacrylamide, itaconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, methacryloyl Examples thereof include nitrile, styrene, and α-methylstyrene. Among them, hydrophilic and water-soluble comonomers are preferred. The polymerization degree of such an acrylonitrile-based polymer is the 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 modulus of the coagulated fiber, which is a process yarn in wet spinning, and the quality of the final fiber bundle obtained by post-processing this fiber as a filament bundle such as a single fiber cut or a fluff. I found a relationship with the phenomenon. That is, the tensile modulus of the coagulated fiber is about 2.0
When it is ｇ3.0 g / d (d = denier is based on the weight of the polymer component in the coagulated fiber), the fiber bundle obtained by further post-treatment such as drawing, washing and drying of the coagulated fiber is ,
It has very few single fiber breakage and fluff, and has stable high quality despite being obtained by wet spinning.

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 a coagulating liquid, and the fineness of the obtained fiber bundle is extremely uneven. Become. Furthermore, the fluctuation of the stretchability in each spinning step becomes remarkable, which causes breakage of a single fiber and makes continuous spinning of a stable filament bundle difficult. On the other hand, the tensile modulus is about 3.
If it exceeds 0 g / d, the single fiber breakage in the coagulation bath and the drawability in the subsequent step are caused, and a fiber bundle satisfying all mechanical properties, quality and production stability 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 if added, and also the spinning stock solution concentration, coagulation conditions (coagulation solution composition, temperature, coagulation draft, etc.) and coagulated fiber. It is determined by factors such as fineness.

A production example of the acrylonitrile filament bundle of the present invention will be described. The polymerization method of 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 in 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 performed directly on the coagulated fiber, or may be performed after the coagulated fiber is drawn in advance in the air. Stretching in the bath is usually performed in a stretching bath at 50 to 98 ° C. once or twice or more in multiple stages, and washing may be performed before, after, or in the middle, but the present invention is not limited thereto. By these operations, it is preferable that the coagulated fiber is stretched about three times or more by the time when the stretching in the bath is completed.

The fiber after drawing and washing in a bath can be treated with an oil agent and dried by any known method. For example, drying can be performed by using a heating roller (or hot drum) having multiple stages 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, facility of the facility, and the like. If necessary, before or after drying, the fiber may be further stretched by a hot roller or pressurized steam.

[0014]

The present invention will be described in detail with reference to the following examples. "%" Represents% by weight. (A) "Tensile elasticity of coagulated fiber": After collecting coagulated fiber bundle, immediately pulling by Tensilon at a sample length (gripping 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 modulus of elasticity is expressed by the following formula: denier (d; coagulated fiber bundle 900) of the coagulated fiber bundle.
The weight occupied by the polymer per 0 m) was obtained and shown in g / d. d = 9000 × f × Qp / V f: number of filaments, Qp: discharge amount of polymer per one nozzle hole (g / min), V: coagulated fiber take-off speed (m
/ Min) (b) "Intrinsic viscosity of polymer [η]": Measured with a dimethylformamide solution at 25 ° C.

Example 1 and Comparative Example 1 93% of acrylonitrile, diacetone acrylamide 7
% Of a 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 hole diameter of 0.08 mmφ and a 12,000 hole. Coagulation draft 0.8 (coagulation draft =
Wet spinning was carried out at a coagulated fiber take-off speed / spun stock solution discharge linear speed). Table 1 shows the tensile modulus of the obtained coagulated fiber bundle. This coagulated fiber is washed and desolvated while being stretched 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 of 2.0.
d, a fiber bundle of 12,000 filaments was obtained. At the time of spinning, the 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 fiber bundle was shown in Table 1 as the fluff frequency.

[0016]

[Table 1]

Comparative Example 2 A copolymer consisting of 93% of acrylonitrile and 7% of methyl acrylate and having an intrinsic viscosity [η] of 1.8 was prepared at a copolymer concentration of 2
Dissolve in dimethylacetamide at 0% to make a spinning stock solution,
The coagulation bath conditions were 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 the measurement of single fiber breakage and fluff was performed in the same manner as in the example, the fluff frequency was 8.4.

Example 2 A mixture of 90% acrylonitrile and 10% methacrylic acid 2-hydroxyethyl ester has an intrinsic viscosity [η] of 1.8.
Was dissolved in dimethylacetamide at a copolymer concentration of 20% to prepare a spinning dope, and the pore size was 0.075 mmφ,
Using a 2000-hole nozzle, the mixture was discharged into a coagulation bath having a dimethylacetamide concentration of 65% and a temperature of 35 ° C. to perform wet spinning. At this time, the solidification draft was changed by increasing or decreasing the discharge amount of the undiluted solution, and thereafter spinning was performed in the same manner as in the example. The tensile modulus of the coagulated fiber bundle and the fuzz frequency immediately before the winder under the respective coagulation draft conditions were measured, and the results are shown in Table 2.

[0019]

[Table 2]

Claims (1)

(57) [Claims] 1. An acrylonitrile-based filament bundle obtained by wet spinning an acrylonitrile-based polymer and setting the tensile modulus of the coagulated fiber to about 2.0 to 3.0 g / d.