JPS61160416A - Production of acrylonitrile fiber - Google Patents

Abstract

PURPOSE:To produce the titled fiber at a high speed, without using water as a plasticizer of polymer, saving the labor of the adjustment of the spinning dope and the recovery of solvent, by melting an acrylonitrile polymer having a reduced viscosity of lower than a specific level at a specific temperature, and extruding and drawing the molten polymer. CONSTITUTION:An acrylonitrile polymer having a reduced viscosity of <=1.0, preferably 0.2-0.6 and composed of 80(wt)% acrylonitrile and <=20% copolymerizable unsaturated monomer [e.g. methyl (meth)acrylate] is melted at 150-300 deg.C, extruded through a nozzle, and drawn to obtain the objective fiber having a crystallinity of preferably >=30%. The spinning speed is preferably >=500m/min.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for melt-spinning acrylonitrile-based polymers, particularly a method for melt-spinning at high speed without using water as a compensating agent for the polymer. It is.

[Conventional technology]

Acrylonitrile fibers have been used as wool-like fibers for a long time, and the manufacturing method is to use acrylonitrile polymers, dimethylformamide, and dimethylacetamide.

A method of dissolving in an organic solvent such as dimethyl sulfoxide or γ-butyrolactone or an inorganic solvent such as an aqueous solution of nitric acid, an aqueous rhodan salt solution, or an aqueous solution of zinc chloride and wet spinning using an aqueous coagulation bath, or using dimethylformamide or nitric acid as the solvent. , a dry spinning method, and an invention in which water is used as a plasticizer for an acrylonitrile polymer and melt-spun to form fibers is described in JP-A-59-163413 or JP-B-59-38243. .

[Problem to be Solved by the Invention 3] The method for producing acrylonitrile fibers using the wet spinning method or dry spinning method described above requires long steps such as preparation of the spinning stock solution, coagulation, solvent removal, washing and stretching, and requires many operations. It is complicated, requires energy costs, and above all, has the disadvantage that high-speed spinning cannot be performed. For this reason, at present there is not much difference in economic efficiency and operability between the dry spinning method and the wet spinning method. As a new spinning method, JP-A-59-
163413, acrylonitrile polymer 1
00 parts by weight, 5 to 40 parts by weight of water and 0.1 parts by weight of hydrophilic polymer.
Transparent acrylonitrile fibers are obtained by mixing ~30 parts by weight, melting the fibers without volatilizing water, and ejecting them from a spinneret and drawing them in water. It is necessary to devise an extruder to prevent this, and it is difficult to control the water in the melt, and it is necessary to draw the spun fibers in hot water. It evaporates and turns white. In addition, about 10% by weight of polyethylene glycol contained in the spun fibers needs to be washed away with water to avoid any inconvenience to the fibers, so the technique is still insufficient as a melt-spinning method for acrylonitrile fibers.

A major feature of the melt spinning method is the ability to perform high-speed spinning, but the spinning speed in the production of acrylonitrile fibers by wet spinning is usually in the range of 30 to 150 m7. The spinning speed in the method of melt spinning by coordinating water to the coalescence is at most 50%.
The spinning speed is limited to 0 m/min, and it is said that it is impossible to increase the spinning speed to 500 m/min or more, which is the speed in melt spinning of polyester, nylon, etc., for example.

[Means for solving problems]

Therefore, the present inventors did not use water as a plasticizer.
As a result of intensive research into a method for producing acrylonitrile fibers by melt-spinning acrylonitrile polymers, we found that
Reduced viscosity is 1. By using an acrylonitrile polymer having Q or less, the inventors have found that the object can be achieved and completed the present invention.

That is, the gist of the present invention is to prepare an acrylonitrile-based polymer comprising 90% by weight or more of acrylonitrile and 20% by weight or less of an unsaturated monomer copolymerizable with the reduced viscosity of 1.0 or less. , melted at 150 to 300°C, discharged from a nozzle and stretched, and produced acrylonitrile fiber by a melt spinning method.

The acrylonitrile polymer used in carrying out the present invention must contain 80% by weight or more of acrylonitrile. If this amount is less than 80% by weight, the amount of copolymerized components will increase and the fiber will not be able to exhibit its full potential.

Other unsaturated monomers that can be copolymerized with acrylonitrile include acrylic acid and methacrylic acid.

Unsaturated carboxylic acids such as itaconic acid and their salts, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate.

Acrylic acid esters such as methoxyethyl acrylate, phenyl acrylate, and cyclohexyl acrylate, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, methoxyethyl methacrylate, phenyl methacrylate, and cyclohexyl methacrylate. Acid esters, methyl vinyl ketones, vinyl acetate, vinyl propionate.

Vinyl esters such as vinyl butyrate and vinyl benzoate; vinyl sulfonic acids and their salts such as methyl vinyl ether, vinyl sulfonic acid and p-styrene sulfonic acid; vinyl halides or halides such as vinyl chloride, vinylidene chloride, and vinyl bromide. Vinylidenes, vinylpyridine.

Examples include basic vinyl compounds such as vinyl imidazole and dimethylaminoethyl methacrylate, and vinyl compounds such as acrolein and methacrolein.

It is essential that the acrylonitrile polymer used in the present invention has a reduced viscosity of 1.0 or less, and it is particularly preferable to use one having a reduced viscosity of 0.2 to 0.6.

It has a reduced viscosity of 1.5 to 2.5, which is significantly lower than that of acrylonitrile polymers used in the production of conventional acrylonitrile fibers, and exhibits extremely good melt fluidity at temperatures of 150"C or higher. The acrylonitrile polymer used in the present invention exhibits good crystallinity, and can be easily discharged from a nozzle with a small hole diameter.
If the fiber is oriented by applying draft and drawing, it can be made into a fiber having a strength of 3 P/d or more.

Acrylonitrile polymers with such properties are
Although it can be produced by solution polymerization, suspension polymerization, emulsion polymerization, etc., acrylonitrile polymers obtained by emulsion polymerization have excellent handling properties. Emulsifiers used in the emulsion polymerization method include anionic surfactants such as aliphatic soaps, alkyl sulfates, dialkyl sulfosuccinates, sulfonated esters, and sulfonated amides;
Fatty acid esters of polyols such as polyethylene glycol and polypropylene glycol, nonionic surfactants such as nlupitan aliphatic esters, and the like can be used. Molecular weight modifiers include propyl mercaptan, butyl mercaptan, isopropyl mercaptan,
Mercaptans such as butyl mercaptan, benzyl mercaptan, octyl mercaptan, and lauryl mercaptan are used.

These molecular weight regulators may be used alone or in combination of two or more as necessary. As the polymerization initiator, any initiator used in normal radical polymerization can be used, including inorganic initiators such as potassium persulfate, and azobisisobutyronitrile.

Examples thereof include azo initiators such as 2.2'-azobis+2.4-dimethylvaleronitrile] and peroxides such as cumene peroxide and benzoyl peroxide.

The acrylonitrile polymer produced by the emulsion polymerization method as described above contains almost no unpolymerized acrylonitrile, has good melt formability, has extremely low thermal decomposition during heating and melting, and has a long lifespan. Even during melt spinning for hours, almost no thermal coloring occurs.

Various methods can be used to heat and melt the acrylonitrile polymer having the above-mentioned reduced viscosity and form it into fibers, but a method in which the acrylonitrile polymer is heated and melted using a screw extruder and then discharged from a spinning nozzle is preferred. The heating and melting of acrylonitrile polymers depends on the composition of the polymer used.
The temperature is 0°C to 300°C. If the heating temperature of the polymer is too low, fluidity during melting will be poor and spinnability will be reduced, which is not desirable. On the other hand, heating to a temperature higher than 300° C. causes decomposition of the polymer and tends to cause foaming, which is not preferable. The spinning speed should be 500 m/min or more to obtain crystalline fibers.

It is preferable because it is good in terms of fiber performance such as degree of orientation.

Stretching is performed to improve the orientation degree 2 strength of the fibers obtained by the melt spinning method, and the methods include the hot bottle stretching method, hot roller stretching method, or hot pin stretching method such as diving, which is used in the usual melt spinning method. Various methods can be adopted.

The fibers obtained by the above method can have a wide range of fineness such as 0.1 to 50 denier, strength of 3 to 30 //d, and Young's modulus of 10 to 100 y/d.
, The elongation can be 10 to 50%.

The fibers obtained by the present invention have extremely excellent transparency because they do not contain the voids found in acrylonitrile fibers obtained by conventional methods, and there is little devitrification phenomenon during dyeing, resulting in vivid dyed products. be able to. It is also possible to form composite fibers with other melt-formable polymers, such as polyester and polyamide.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that the reduced viscosity ηred and the crystallinity of the obtained fibers were measured by the following method.

-Reduced viscosity: 0.5 mm of acrylonitrile-based polymer was dissolved in dimethylformamide to make the total amount 100 m, and the viscosity value measured at 25°C with an Ostwald viscometer was defined as the reduced viscosity.

・Crystallinity of fiber; CuKα (1,54X) as X-ray
scattering angle 2θ using characteristic X-rays and a rotating sample stage.
Act is the sum of the peak areas due to crystal parts observed near 20=17° and 30′ in the X-ray diffraction diagram measured in the range of =100 to 35°.

Let the total area of the halo due to the amorphous part be AA, and Ac/
A simple method was used in which (AA+AO) x 100 (%) was defined as the degree of crystallinity.

Example 1, Comparative Example 1 In a polymerization tank equipped with a nitrogen introduction tube, a cooling tube, and a dropping funnel, 100 parts of deionized water and anionic surfactant dioctyl sodium sulfosuccinate (trade name, Perex 0TP) were added.
), 1 part of potassium persulfate, 0.05 part of potassium persulfate, 17 parts of a polymerizable unsaturated monomer with the weight ratio of acrylonitrile/methyl acrylate shown in Table 1, and lauryl mercaptan in the amount shown in Table 1. was charged and heated to 55"C to start polymerization. After 30 minutes, a mixture containing 33 parts by weight of a polymerizable unsaturated monomer mixture having the same composition as the charge and the amount of lauryl mercaptan shown in Table 1 was added. It was added dropwise over about 1.5 hours, and after completion, the polymerization temperature was raised to 80°C, and the polymerization was completed by heating for 1 hour.The resulting polymer slurry was coagulated and solidified according to a conventional method, washed, and heated at 60°C Dry and turn white,
A powdered polymer was obtained. Table 1 shows the polymerization rate and reduced viscosity of the polymer.

The acrylonitrile polymer obtained in the manner described above was heated and melted using a screw extruder, then extruded at a nozzle temperature of 230°C, and wound up at a speed of 1000 ml per minute. The properties are shown in Table 1.

A significant improvement in sexual performance can be expected. Furthermore, in terms of performance, it is significantly superior to conventional acrylonitrile fibers in terms of yarn density and strength, and is expected to be used not only as a clothing fiber but also as a wide range of industrial materials.

Procedural amendment May 21st, 1985

Claims (1)

[Claims] 1. Consists of 80% by weight or more of acrylonitrile and 20% by weight or less of an unsaturated monomer copolymerizable, and has a reduced viscosity of 1.0.
The following acrylonitrile polymer is used at 150 to 30
A method for producing acrylonitrile fiber using a melt spinning method, which comprises melting the fiber at 0° C., discharging it from a nozzle, and stretching it. 2. The manufacturing method according to claim 1, wherein the crystallinity of the obtained fiber is 30% or more. 3. The manufacturing method according to claim 1 or 2, wherein the spinning speed is 500 m/min or more. 4. The manufacturing method according to claim 1, 2, or 3, characterized in that the film is stretched and oriented by a factor of 2 or more by a hot pin stretching method, a hot roller stretching method, or a hot water stretching method.