JPS62162011A - Production of modacryl fiber of high flame retardancy - Google Patents

Abstract

PURPOSE:A modacrylic polymer containing vinyl chloride and vinylidene chloride is dissolved in an organic solvent, a specific dispersion is admixed thereto, and the resulting dope is subjected to extrusion into fiber whereby the titled modacrylic fiber which is brightly dyeable is obtained. CONSTITUTION:A modacrylic polymer containing vinyl chloride and/or vinylidene chloride is dissolved in an organic solvent such as DMF. The solution is combined with a dispersion which is prepared by dispersing antimony pentoxide in a solution of an acrylic polymer containing anionic monomers as copolymerization components in an organic solvent to prepare a spinning dope. The spinning dope is extruded into a coagulation bath of an aqueous solution of organic solvent, then drawn and dried to give the objective modacrylic fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing highly flame-retardant modacrylic fibers.

(Prior Art) Acrylic fibers have many excellent chemical and physical properties such as dyeability, texture, and light resistance.

However, in recent years, our living environment has become increasingly exposed to the risk of disasters such as fire, and as people's living standards have improved, the demand for flame-retardant textile products has rapidly increased. The flammability of synthetic fibers, especially acrylic fibers, has become a major problem. Since acrylic fibers inherently lack flame retardancy, it is not preferable to use them in interior products such as curtains and carpets that require disaster prevention properties, or in clothing such as sleeping clothes for infants and the elderly.

In order to improve these drawbacks, a method has been proposed in which flame-retardant monomers such as vinyl chloride, vinylidene chloride, and vinyl bromide are copolymerized with acrylonitrile (hereinafter abbreviated as AN), and various modacrylic fibers have already been used as fabrics. has been done.

On the other hand, there is a demand for blending these modacrylic fibers with 10 to 80 natural fibers to improve texture and moisture absorption, and for high-density curtains that require high flame retardancy. In order to meet these demands, there is a method of increasing the ratio of flame-retardant monomers, but the quality is lower than that of the modacrylic fibers, such as a marked decrease in heat resistance, a large degree of coloration, and a decrease in dyeability. Significantly decreased. Therefore, flame retardant additives mainly consisting of metal compounds such as antimony trioxide, antimony pentoxide, tin oxide, barium borate, zinc borate, and zirconium oxide are added to the modacrylic fiber to improve heat resistance and stability. A method has been proposed to obtain highly flame-retardant fibers without deteriorating quality such as colorability and dyeability. This will impair card passing properties, spun yarn breakability, spinning properties such as knitting and weaving properties, bright color tone, etc.
A fiber that satisfies high flammability, workability, spinnability, and quality has not yet been obtained. For example, Japanese Patent Publication No. 54-278848 discloses that an acetone- or acetonitrile-insoluble flame retardant additive (for example, a metal compound such as antimony trioxide or barium borate) is pulverized in an acetone or acetonitrile solution containing a dispersing polymer. It is proposed that troubles such as filtration and nozzle clogging can be avoided by pulverizing the flame retardant additive into an ultra-fine powder, which involves dispersion and dispersion at the same time, and then adding it to the spinning stock solution and spinning. are doing. However, it is difficult and impractical to carry out the grinding and dispersion continuously and in an industrially advantageous manner. Furthermore, Japanese Patent Publication No. 58-15170 discloses A copolymerized with a halogen-containing unsaturated monomer.
A spinning dope in which antimony oxide having a particle size of 100 mμ or less is dispersed in a solvent solution of an N-based polymer composition is wet-spun, and the internal moisture content of the gel-like fiber is adjusted to 50 to 180% by weight, and then dried. A method for producing a flame-retardant acrylic fiber that has excellent transparency and gloss due to its densification is described. However, as in this method, antimony oxide, especially 1
Particulate antimony oxide having a particle size of 00 mμ or less tends to cause secondary aggregation in a solvent solution, and secondary aggregation is particularly large when the solvent is an organic solvent such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, or acetone. There is a significant decrease in operability due to increased filtration pressure and nozzle clogging. In addition, in the case of wet spinning using the above-mentioned organic solvent, the internal moisture content of the gel-like fiber is generally 180 to 170% by weight), and it is almost difficult to increase the internal moisture content to 50 to 180% by weight like inorganic solvents. It's fine.

(Problems to be Solved by the Invention) An object of the present invention is to provide a highly flame-retardant modacrylic fiber with good brightness after dyeing. Another object of the present invention is to provide a method for producing highly flame-retardant modacrylic fibers that does not cause an increase in filtration pressure due to secondary agglomeration of antimony pentoxide, allows stable spinning for a long period of time, and has less yarn breakage during spinning.

(Means and effects for solving the problems) According to the present invention, the above objects and advantages of the present invention are achieved by
Alternatively, a spinning stock solution containing vinylidene chloride dissolved in a modacrylic polymerization termination organic solvent is spun into a coagulation bath consisting of an aqueous solution of the organic solvent to form modacrylic l#1. ia, is achieved by adding and mixing into the spinning stock solution a dispersion in which antimony pentoxide is dispersed in an organic solvent solution of an acrylic polymer containing an anionic monomer as a copolymerization component.

The modacrylic polymer used in the method of the present invention is a polymer consisting of vinyl chloride and/or vinylidene chloride, AN and sulfonic acid monomer, and the appropriate proportion can be determined depending on the application, but AN4 Ox voluminous or higher, vinyl chloride and/or vinylidene chloride 20-60% by weight, and sulfonic acid-containing monomer 5 irises J! : A polymer consisting of 96 or less is preferred.

The concentration of modacrylic polymer in the spinning stock solution is usually 20 to 8
5% by weight, preferably #-1-28 to 80% by weight. In addition, there is no problem even if the spinning dope contains 10% by weight or less of water in addition to the modacrylic polymer and the solvent. In particular, when 2 to 6% of water is present, dense fibers with few voids can be obtained. This is preferable because it also reduces the burden of solvent recovery. The solvent of the spinning dope is not particularly limited as long as it dissolves the modacrylic polymer, but preferably dimethylformamide, dimethylacetamide, acetone or dimethylsulfoxide.
Further, there is no problem even if the water content is 10% by weight or less.

The organic solvent concentration in the coagulation bath is generally 40 to 70% by weight, preferably 50 to 66% by weight. The temperature I/'i of the coagulation bath is generally 10 to 60°C, preferably 1
The temperature is 5 to 50°C.

The anionic monomers of the acrylic polymer used in the dispersion include acrylic acid, methacrylic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-
There are acrylamide 2-methylpropanesulfonic acid and salts thereof. Preferably, 2-acrylamide 2-methylpropanesulfonic acid (hereinafter referred to as AMPS) or sodium 2-acrylamide 2-methylpropanesulfonic acid (hereinafter referred to as SAMJ'S) is preferred.

Acrylic polymer rIi usually acrylonitrile 80-9
5% by weight, 20 to 5% by weight of anionic monomer, and 0 to 20% by weight of other copolymer components.

The dispersion used in the present invention consists of an organic solvent, an acrylic polymer, and antimony pentoxide. (The acrylic polymer in the dispersion is antimony pentoxide) It is better to first dissolve it in an organic solvent and stir it, and then add the antimony pentoxide. By doing so, a film of the acrylic polymer is formed on the surface of the antimony pentoxide dispersed in the organic solvent, and secondary aggregation of the antimony pentoxide can be prevented. Conversely, when producing a dispersion, adding an organic I@ solution of an acrylic polymer to a solution of antimony pentoxide in an organic solvent may cause secondary aggregation of antimony pentoxide. Of course,
Antimony pentoxide alone is stable in an organic solvent solution and does not cause secondary aggregation, but when added as is to a modacrylic polymer spinning stock solution, it causes secondary aggregation, resulting in an increase in lacrimal overpressure.
This is undesirable because it causes nozzle clogging.

The concentration of the acrylic polymer in the inferior liquid is usually 10 μm or less, preferably 2 to 8 μm.

The concentration of antimony pentoxide in the dispersion is usually 5 to 40 g, preferably 10 to 20 g.

The particle size of the antimony pentoxide used is not particularly limited, but in applications requiring transparency and gloss, it should be 100 mμ or less, preferably 10 to 80 mμ. In general, as the particle size of antimony pentoxide becomes smaller, secondary aggregation is more likely to occur.In particular, when antimony pentoxide with a particle size of 10 to 80 mμ is used, an acrylic polymer is added to the dispersion as in the present invention. It is important to form a film on the surface of antimony pentoxide and prevent secondary agglomeration.

Antimony pentoxide may be in powder form if the particle size is 800 mμ or more, but if it is smaller than that, especially 100 mμ
Colloids of organic solvents are preferred for particles having the following particle sizes. Not limited to antimony pentoxide, metal compounds in general, even if they are in powder form, are dispersed in an organic solvent.
It is well known that secondary aggregation occurs. Therefore, the dispersion is preferably a mixture of an organic solvent solution of the acrylic polymer and the specific solvent colloid of antimony pentoxide. Further, the concentration of antimony pentoxide in the organic solvent colloid is not particularly limited, but generally, the lower the concentration, the better the dispersion stability. The preferred antimony pentoxide concentration is aio to 60% by weight. The dispersion is added to and mixed with the modacrylic polymer spinning stock solution, but in general, antimony pentoxide is added in an amount of 1 to 1 per the total amount of modacrylic polymer.
0% by weight, preferably 1 to 5% by weight. When the dispersion liquid is added to the modacrylic polymer spinning dope, the addition location may be anywhere after the unreacted monomers have been collected after the completion of polymerization, but it is preferably added immediately before spinning.

Note that the equipment for addition and mixing is not particularly limited, but a homomixer is preferable because homogenization can be achieved in a short time. After spinning, water washing, stretching, pre-oil application, drying, stretching, post-oil application,
Not only processes such as crimper, crimp setting, and drying, but also normal processes for modacrylic fibers can be applied as they are.

(Effect of the invention) By adding and mixing the thus obtained dispersion into the organic solvent spinning dope of modacrylic polymer, secondary aggregation of antimony pentoxide can be prevented, so there is no need to increase the filtration pressure or clog the nozzle, and the process can be carried out for a long time. An acrylic polymer that can be spun stably over time and does not cause yarn breakage during spinning, and which contains antimony pentoxide of 100 mμ or less and an anionic monomer used in the dispersion as a copolymer component, can be reused after dyeing. Highly flame-retardant modacrylic fibers with good pliability and no devitrification can be easily produced.

The highly flame-retardant modacrylic fiber of the present invention may be applied to high-density curtains, and flame-retardant fibers such as natural fibers may be used in
Clothes made from a blend of 80% by weight still have sufficient flame retardancy. In addition, when antimony pentoxide with a particle size of 100 mμ or less is used, fibers with good brightness can be obtained, which is very useful because the bright coloring properties of cationic dyes can be utilized as they are.

(Examples) The present invention will be explained in detail below using examples. It should be noted that all parts and parts shown in the examples are based on weight unless otherwise specified. In addition, the method for measuring characteristic values in Book M of this specification will be described first.

8. Transparency of fibers (BA value) Straighten the fibers with a hand card, cut them to a length of fJtx, measure them at 0.04 f/cut, put them in a 201 m lath cell with benzyl alcohol, and expose them to light at 562 mμ. Measure the transmittance using a spectrophotometer. Note that the comparison was made with the transmittance of benzyl alcohol as 100.

B Flame retardancy of fibers was determined by the limit acid index method (LOI). That is, 8 denier highly flame-retardant modacrylic fiber was cut into 5 cm pieces, and 0.8
We measured 5g and made 12 pieces.

This was placed upright in the holder of an oxygen index tester, and the minimum oxygen concentration required for this sample to continue burning for 5 cm was measured, and this was taken as the LOI value.

C filtration test The spinning solution was heated to 60°C and the filtration amount was 15. Oml, 7hd was filtered, and the filtration pressure increase over 60 minutes was measured. Note that Gosamine was used as the furnace material.

D Water swelling degree The gel-like modacrylic fibers (through the spinning, stretching, and water washing processes) and before the drying process were put into a centrifugal dehydrator and heated at 8000 r.
, p, m for 2 minutes, and then the moisture content (chi) remaining in the gelled modacrylic fibers was measured by the loss on drying method. From the measured moisture content, a constant [1(
The value obtained by subtracting 1 (excess moisture content not related to the internal moisture content) was adopted as the water swelling degree.

Example 1 4 parts of an acrylic polymer of AN/SAMPS=80/20 (weight ratio) was dissolved in 46 parts of dimethylformamide (hereinafter abbreviated as DMF) solvent, and the average particle size was determined while stirring and mixing the solution. 80 of antimony pentoxide of 40mμ
%DMF colloid was gradually added thereto to obtain a dispersion.

Next, 20 parts to 100 parts of a DMF solution containing 25% of the modacrylic polymer having the above composition and 6 parts of water were added and mixed with a homomixer while stirring to obtain a spinning stock solution.

This spinning dope was passed through a spinning rod with a pore size of 0.06 tl-X8000), and the spinning bath DMF/water = 60/40 (weight ratio)
Spun at 22°C. In addition, after spinning for 1 hour, there was no increase in candle pressure or nozzle pressure, and there was no single yarn breakage.
After various steps such as drying, a single filament of 8 denier was obtained. The degree of water swelling of the yarn washed with water after stretching at a spinning ratio of 4 times is 1.
It was 65%. In addition, the strength and elongation of the obtained fiber was 8.4.
9/d, 42%, oxygen index LOI was 84, transparency BA value was 88%, and BA value was 75 after seawater treatment.

Comparative Example 1 51 except that 4 parts of modacrylic polymer in the dispersion was not added.
! A spinning stock solution was obtained in the same manner as in Example 1, and spinning was performed in the same manner as in Example 1. Single yarn breakage situation at that time and results of nine filtration tests using the above spinning stock solution Table 1 Filtration pressure/single yarn breakage Example 2 The same procedure as Example 1 was carried out except that 140 parts of the same dispersion as in Example 1 was added. A spinning stock solution was obtained. The spinning stock solution was mixed with a pore size of o.
Spinning bath D is passed through the osg-1 hole number 8000H
It was spun at 18° C. with a MF/water content of 5 5/4 5 (weight ratio).

In addition, during spinning for 1 hour, there was no increase in candle pressure or nozzle pressure.
In addition, it was possible to spin the yarn without any breakage. The degree of water swelling of the washed yarn after spinning and stretching 8.5 times was 175%. Further, drying, crimping, and crimp setting were performed for 150 times to obtain a filament with a single yarn denier of 8 denier. The obtained fiber had a strength and elongation of 8.2 g/d, 85 inches, an oxygen index LOIH of 85, a transparency BAitFi of 85 inches, and 72% after seawater treatment. The amount of antimony pentoxide determined by fluorescence X1lAK was 4.1φ.

Example 8 2 parts of the same modacrylic polymer as in Example 1 was dissolved in 48 parts of DMF, and while the solution was stirred and mixed, 8 parts of DMF colloidal antimony pentoxide with an average particle size of 40 mμ was dissolved.
26 parts of the os solution was gradually added to obtain a dispersion.

Next, 25% of the same modacrylic polymer as in Example 1 and 61% of water were added.
160 parts of a DMF solution containing 0% were added and mixed with stirring using a homomixer to obtain a spinning stock solution. This spinning stock solution was passed through a pore size of 0.06 m (
, spun at 20°C. Although spinning was carried out for 1 hour, the spinning was completed without any increase in candle pressure or spindle pressure or single yarn breakage.
After various steps such as drying, a single filament of 8 d was obtained.

The degree of water swelling of the washed yarn after stretching at a spinning ratio of 4.5 times was 155%. The strength and elongation of the obtained fiber was 8.1 g/
d, 87chi, oxygen index LOI is 84, transparency BA value is 8
7 inches, and 75 inches after seawater treatment.

Claims (12)

[Claims] (1) When producing modacrylic fiber by spinning a spinning dope in which a modacrylic polymer containing vinyl chloride and/or vinylidene chloride is dissolved in an organic solvent into a coagulation bath consisting of an aqueous solution of the organic solvent, anionic monomers are used. A method for producing a highly flame-retardant modacrylic fiber, which comprises adding and mixing into the spinning stock solution a dispersion in which antimony pentoxide is dispersed in an organic solvent solution of an acrylic polymer containing as a copolymerization component. (2) Modacrylic polymer is 40% by weight of acrylonitrile
Above and vinyl chloride and/or vinylidene chloride 20-60
% by weight of a sulfonic acid-containing monomer and 5% by weight or less of a sulfonic acid-containing monomer. (3) The manufacturing method according to claim 1, wherein the solvent of the spinning stock solution is dimethylformamide, dimethylacetamide, acetone, or dimethylsulfoxide. (4) The anionic monomer is sodium allylsulfonate,
The manufacturing method according to claim 1, which is at least one selected from sodium methallylsulfonate, sodium 2-acrylamido-2-methylpropanesulfonic acid, and sodium 2-acrylamido-2-methylpropanesulfonate. (5) The production method according to claim 1, wherein the anionic monomer is 2-acrylamide 2-methylpropanesulfonic acid or sodium 2-acrylamide 2-methylpropanesulfonate. (6) Acrylic polymer is acrylonitrile 80-95
% by weight, 20-5% by weight of anionic monomer and 0-20% by weight of other copolymer components. (7) Acrylic polymer is acrylonitrile 40-90
20-5% by weight of anionic monomer and 40-5% by weight of vinyl chloride and/or vinylidene chloride. (8) The manufacturing method according to claim 1, wherein the average particle size of the antimony pentoxide is 10 to 80 millimicrons. (9) Acrylic polymer concentration in the dispersion is 2 to 8% by weight
The manufacturing method according to claim 1. (10) Antimony pentoxide concentration in the dispersion is 10 to 20
% by weight. (11) The manufacturing method according to claim 1, wherein the dispersion liquid is a mixture of an organic solvent solution of an acrylic polymer and the organic solvent colloid of antimony pentoxide. (12) The production method according to claim 11, wherein the concentration of antimony pentoxide in the organic solvent colloid is 10 to 50% by weight.