JPH03227404A - Superfine acrylic multifilament having high tenacity - Google Patents

Abstract

PURPOSE:To obtain the subject superfine and high-tenacity filament for clothing or interior decoration goods, etc., having a specific single fiber fineness, improved tensile strength and resistance to repeated washing. CONSTITUTION:For instance, (A) an acrylonitrile-based polymer having >=20X10<4> weight-average molecular weight composed of >=80wt.% acrylonitrile and other copolymerizable components is dissolved in a solvent (e.g. dimethylformamide) and filtered through a filter having <=10mu mesh, then extruded from a spinning nozzle having <=50mu capillary diameter to afford the aimed filament having <=0.05d single fiber fineness and >=5g/d tensile strength measured with multifilament.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel high-strength ultra-fine acrylic multifilament having a single fiber fineness of 0.05 d or less.

(Prior art) Acrylic fiber is known for its excellent physical properties such as color development, clarity, fastness, dyeability, and light resistance, and is widely used mainly in clothing and interior decoration products. . By the way, conventionally commercially available acrylic fibers are manufactured using wet, dry-wet, or dry spinning methods, all of which involve a very complicated process of dissolving the polymer in a solvent, shaping it into fibers, and then removing the solvent. In need of. In general, fibers are made thinner (thinner fibers tend to get wrapped around rollers, guides, etc. during the spinning process, causing fuzzing, etc., so composite spinning technology is applied, for example, by post-processing, fibers that have been spun can be divided into sea-island fibers, etc.). After that, the sea component is eluted, leaving only the island component.

With melt spinning of nylon, polyester, etc., the process is simple and it is possible to obtain ultrafine fibers using this method, but in the case of acrylic fibers, the spinning process is complex, so ultrafine fibers are produced by composite spinning. That was difficult.

Therefore, as an extension of the conventional acrylic fiber manufacturing technology for clothing, the nozzle hole diameter is reduced and the drawing ratio is increased (by which the fineness is reduced), but with this method, the limit is 0.1 d. be.

Conventional production of ultra-fine acrylic fiber (Japanese Patent Application Laid-Open No. 54-23726
(Japanese Patent Application Laid-open No. 61-167012) and the production of multifilaments (Japanese Patent Application Laid-open No. 61-215712), however, it has not been possible to produce the high-strength ultra-fine acrylic multifilament that is the object of the present invention. It wasn't very satisfying.

(Problems to be Solved by the Invention) The object of the present invention is to provide an ultra-fine and highly strong acrylic multifilament that is extremely difficult to manufacture using conventional methods.

(Means for Solving the Problems) The gist of the present invention is to consist of an acrylonitrile polymer having a weight average molecular weight of 200,000 or more, a single fiber fineness of 0.05d or less, and a tensile strength measured with a multifilament. High strength ultra-fine acrylic multifilament of 5g/d or more.

The acrylonitrile polymer used for producing the high-strength ultra-fine acrylic multifilament of the present invention needs to have a weight average molecular weight of 200,000 or more. In order to produce high-strength ultra-fine acrylic multifilament, it is necessary to lower the acrylonitrile polymer concentration in the spinning dope and to minimize the ratio of the linear velocity of the spinning dope from the spinning nozzle to the speed of undrawn yarn (spinning draft). High (need to)

Therefore, it is preferable to set the concentration of the acrylonitrile polymer in the spinning stock solution to 10 wt% or less, but if the weight average molecular weight of the polymer used is less than 200,000, the spinning stock solution with such a low concentration may be adjusted. However, the viscosity of the yarn decreases, and the spinnability decreases, making it difficult to continue spinning stably.

The acrylonitrile polymer used in the present invention must contain 80 wt % or more of acrylonitrile in view of the physical properties of the resulting fiber. Components copolymerized with acrylonitrile include methacrylic acid, methyl acrylate or methacrylate, ethyl acrylate or methacrylate, n-iso- or t-butyl acrylate or methacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, hydroxyalkyl acrylate or methacrylate. , vinyl chloride,
Examples include unsaturated monomers such as vinylidene chloride, vinylidene bromide, vinyl acetate, sodium salt of p-sulfophenyl methallyl ether, sodium methallyl sulfonate, but any monomer that copolymerizes with acrylonitrile may be used. , two or more types of monomers can also be used in combination.

Such an acrylonitrile polymer is dissolved in a solvent such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, a rhodan salt aqueous solution, or a zinc chloride aqueous solution. Subsequently, such a spinning stock solution is filtered through a filter medium with an opening of 10 μm or less, and is discharged from a spinning nozzle. The smaller the hole diameter of the spinning nozzle is, the more preferable it is, and the diameter of the spinning nozzle is preferably 50 μm or less, preferably 4 μm or less.
It is 0μ or less. The number of holes in the spinning nozzle cannot be determined unambiguously from the relationship between single fiber fineness and filament fineness, but it is more than 500 holes and 100. High-strength ultra-fine acrylic multifilaments of 500 to 0,000 filaments can be easily produced as long as the filaments are in the range of 0,000 holes or less.

Wet spinning is preferred as the spinning method.

The coagulation bath uses a mixture of an acrylonitrile polymer solvent and water.

The coagulated thread thus obtained is then stretched while washing and removing the remaining solvent. The stretching method is preferably carried out by setting a high stretching ratio and using a combination of water-conducting stretching and a hot roll, hot plate, hot tube, etc. in order to make the tensile strength of the multifilament 5 g/d or more.

Generally, when the single fiber fineness is made thinner, thread breakage occurs frequently in the coagulation bath and winding around spinning rollers, thread guides, etc., resulting in poor process passability, but surprisingly, the high-strength ultra-fine acrylic multifilament of the present invention Because there are many entanglements between single fibers, its shrinkability is very good, so there is almost no single fiber breakage due to splitting of the spun yarn on the spinning roller or yarn guide, and the processability is very high. In good condition.

The high-strength, ultra-fine acrylic multifilament of the present invention produced in this way has gloss, flexibility, lightness, and water retention that cannot be obtained with conventional acrylic fibers, and has a surface area per fiber weight that cannot be obtained with conventional acrylic fibers. The wiper function is also greatly improved when non-woven fabrics and woven fabrics are made, as the wiper function is significantly increased in comparison. Furthermore, since the high-strength ultra-fine acrylic multifilament of the present invention has improved tensile strength, the durability of nonwoven fabrics and textiles is also greatly improved and can be used repeatedly by washing.

(Example) The present invention will be specifically explained below using Examples.

The weight average molecular weight (M w ) was calculated from the following formula by measuring the intrinsic viscosity of the polymer at 25° C. using dimethylformamide as a solvent.

[η ko = 3. 35xlO-' [Mw Ko 07
4 Example 1, Comparative Example 1 An acrylonitrile-based polymer of acrylonitrile/acrylic acid (94/6 weight ratio) was produced by suspension polymerization, and the spinning stock solution dissolved in dimethylacetamide was passed through a nozzle front filter with an opening of 100 μm to a pore size of 0. When wet spinning was performed in a coagulation bath of dimethylacetamide/water (55/45 weight ratio) at 40° C. from a spinning nozzle with a diameter of 0.03 mm and 4000 or 8000 holes, the results shown in Table 1 were obtained.

Example 2. Comparative Example 2 Example 2. Knitted fabrics were made from the multifilaments obtained in Comparative Example 2 Nos. 2 and 4, and washed in a washing machine for 20 minutes.

The knitted fabric from No. 2 had significant fuzz, but the knitted fabric from No. 4 had almost no fuzz.

Claims (1)

[Claims] 1 High strength ultra-fine acrylic multifilament made of an acrylonitrile polymer with a weight average molecular weight of 200,000 or more, with a single fiber fineness of 0.05d or less and a tensile strength of 5g/d or more when measured with a multifilament.