JPS62263312A - Production of acrylic synthetic fiber - Google Patents

Abstract

PURPOSE:To obtain an acrylic synthetic fiber having high flame-retardance and excellent gloss, transparency and dyeability, by adding an aqueous mixture containing specific amounts of tin oxide and an acid to a spinning dope and spinning the dope. CONSTITUTION:The objective acrylic synthetic fiber can be produced by spinning a spinning dope added with an aqueous mixture containing 10-50(wt)% tin oxide and <=1/2pts., preferably 1/100-1/3pts. of an acid (preferably hydrochloric acid) based on 1pt. of the tin oxide. The acrylic fiber is preferably the one composed mainly of an acrylonitrile copolymer copolymerized with 30-70% vinyl monomer containing halogen and 0.1-10% vinyl monomer containing sulfonic acid group. The solvent of the spinning dope is preferably acetone or acetonitrile.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for producing acrylic synthetic fiber containing tin oxide, which has a high degree of flame retardancy and extremely excellent gloss and transparency.

"Prior Art and Problems" In order to obtain excellent gloss and transparency as well as flame retardant properties by incorporating tin oxide, which is known to impart a high degree of flame retardancy to acrylic fibers, It is necessary to scrape and finely grind the tin oxide so that the tin oxide is uniformly dispersed and contained in the fiber without agglomerating. However, it is extremely difficult to uniformly disperse and contain finely ground tin oxide in fibers without agglomerating them without adding or using dispersants that impair fiber quality. All flame-retardant acrylic synthetic fibers are opaque dull fibers. Therefore, there is a strong desire for an easy and inexpensive method for producing acrylic fibers that have both high flame retardancy and excellent gloss and transparency.

For example, Japanese Patent Laid-Open No. 57-89613 proposes a method using organic tin, which has excellent compatibility with acrylic polymers, as a jlP agent. However, due to its characteristics, organic tin is highly reactive to light and heat (it is inferior in light resistance and heat resistance, which are the basic qualities of fibers, and is extremely expensive, and has low tIR for odor and exhaust gas treatment). Furthermore, since it contains a flame-retardant organic group in its molecule, it has poor flame retardancy.

On the other hand, the present inventors, in JP-A-59-211616, synthesized an acrylic system that achieved both flame retardancy, gloss, and transparency by adding an inorganic tin compound, preferably tin tetrachloride, to an aqueous polymerization reaction mixture. A method for producing fibers was proposed. However, this method also requires new equipment and requires switching of types in the post-polymerization treatment process, so it is industrially disadvantageous in response to the recent trend toward small-lot, high-mix production to meet consumer demands. . Furthermore, if the aqueous polymerization method is not adopted, it is not applicable, and equipment for mixing various additives in a general spinning dope process cannot be used.

[Means for Solving the Problems] In view of the above circumstances, the present inventors added and mixed tin oxide as a flame retardant in the spinning solution process to produce fibers that are not only flame retardant but also have excellent gloss and transparency. As a result of intensive research on the method of obtaining the same, the present invention was arrived at.

That is, the present invention provides an acrylic synthetic fiber that is spun by adding and containing an aqueous mixture containing 10 to 50% by weight of tin oxide and an acid in an amount of 172 or less of the weight of the tin oxide. The content is the manufacturing method.

The acrylic synthetic fiber in the present invention is a synthetic fiber containing a polymer of acrylonitrile as a main component, and preferably contains 30 to 70% by weight of a halogen-containing vinyl monomer, such as vinyl chloride, vinylidene chloride, vinyl bromide, etc. % copolymerized acrylonitrile polymer, more preferably a sulfonic acid group-containing vinyl monomer, such as sodium methallylsulfonate, styrene sulfonic acid sorta, etc., of 0.1%.
~10% by weight and 30~10% of halogen-containing vinyl monomer
It consists of an acrylonitrile-based polymer copolymerized and containing 70% by weight.

By copolymerizing a halogen-containing vinyl monomer with an acrylonitrile polymer, flame retardancy is improved, and by copolymerizing a sulfonic acid group-containing vinyl monomer,
It is possible to add basic properties and functions that are essential for fiber processability and marketability, such as dyeability. In addition, for example, acrylic acid,
Monomers necessary for improving the quality of fibers, such as methacrylic acid and esters thereof, may be copolymerized.

As a flame retardant, tin oxide is preferably uniformly dispersed with an average particle diameter of 0.1 μm or less and contained in the acrylonitrile synthetic fiber at oJ ~ 20% by weight. If it is small and exceeds 20% by weight, basic functions as a fiber such as gloss, transparency, and strength will be impaired. By preferably containing 0.5 to 10% by weight, desired acrylic synthetic fibers can be obtained.

For this purpose, 10% of tin oxide is added to a spinning stock solution in which the acrylonitrile polymer described above is dissolved in an aqueous solvent, more preferably acetone or acetonitrile.
-50% by weight, preferably 20-45% by weight of tin oxide and an acid, preferably hydrochloric acid, as an aqueous mixture containing 1/2 amount, preferably 1/L OO to 1/3 of the weight of said tin oxide. is finely ground and dispersed to an average particle diameter of 0.1 μm or less, and added to the spinning dope.

It is preferable that the amount of acid and water added to the spinning solution be as small as possible in order not to impair the properties of the spinning solution or the fibers to be produced. In order to keep the tin oxide complexed with acid and water stable, it is necessary that the aqueous mixture contains acid in an amount of 1/2 or less, preferably 1/100 to 1/31, of the weight of tin oxide. If the amount of acid exceeds the above range, it will be difficult to wash and remove the acid components in the spinning solution and fibers.
Since it remains in the fibers, it causes rust in equipment used in the manufacturing process and post-processing process, and impairs the effectiveness of other additives contained in the spinning dope. On the other hand, if the acid concentration is too low, the tin oxide component becomes unstable in the water mixture, making it difficult to finely and uniformly disperse and contain the tin oxide in the spinning dope or fiber.

On the other hand, if the tin oxide component is less than 10% by weight, a large amount of water component will be added to the spinning dope, impairing the stability of the spinning dope and making it impossible to obtain dense fibers. On the other hand, when the tin oxide component in the aqueous mixture exceeds 50% by weight, the tin oxide-containing particles become unstable and the particles contained in the spinning dope and fibers aggregate.

The aqueous mixture containing tin oxide to be added to the spinning dope can be prepared by various methods. For example, tin tetrachloride is mixed with water and reacted to obtain an aqueous mixture containing tin oxide and hydrochloric acid, and then mixed with water. A desired composition can be obtained by removing hydrochloric acid using an ion exchange method, a dilute distillation method, or the like. A dehydrochloric acid method in which neutralization is performed using an alkali or the like causes salt or alkali to be contained in the spinning dope, making it impossible to obtain a dense fiber structure.

Replacing some or all of tin tetrachloride with metal tin, tin dichloride, or tin oxide, mixing and reacting with hydrochloric acid, chlorine, hydrogen peroxide, etc., and water, and wet-pulverizing as necessary to produce a similar product. It is also possible to obtain an aqueous mixture, and the mixing order, method, and conditions are not particularly limited, but the aqueous mixture must contain a small amount of tin oxide and acid in the above-mentioned ratio.

Although it is acceptable to contain some or all of the components constituting the spinning dope and other compounds, for example, alkalis and salts may affect the stability of the aqueous mixture and the particles it contains, and may Substances that cause problems in fiber production and impair fiber quality are not preferred.

In aqueous mixtures containing tin oxide and acid, tin oxide has various compositions such as tin hydroxide or combined with acid and water, for example, when the acid is hydrochloric acid, 5nOx (OH)y
A composition collectively referred to as tin oxychloride, represented by cIz, is considered. Thus, particles whose main component is tin oxide are
It is prepared into fine particles that are easily dispersed and contained in the above-mentioned spinning dope and fibers in an extremely fine and uniform manner.

Isolating tin oxide particles in the form of powder, etc. by separating and purifying a cough water mixture will cause the tin oxide to aggregate and become hard, and even if a dispersant is used, it will return to its original fine particles. It is difficult to contain it in a spinning dope or fiber in an extremely fine and uniform manner.

In addition to tin oxide and water, the spinning stock solution contains fiber quality improvers such as light resistance, heat resistance stabilizers, gloss, transparency modifiers, dyes, pigments, other flame retardants, dyeability modifiers, and fiber specific gravity regulators. Compounds such as agents, oligomers, polymers, etc. may be added,
As the spinning method, a known method such as a wet method or a dry method is applied, and a general fiber manufacturing method such as a fiber surface modifier, an oil agent, etc. is preferably applied.

"Action/Effect" According to the present invention, tin oxide can be contained in acrylic fibers in an extremely finely and uniformly dispersed manner. As a result, it is possible not only to impart high quality properties and extremely excellent gloss and transparency to the fibers, but also to greatly improve the dyeability and to obtain fibers of extremely high quality. Moreover, in addition to the addition of fine tin oxide in the spinning dope process, it is also possible to freely add other quality improvers, resulting in fibers with extremely high gloss, transparency, and high flammability. In addition, a wide variety of fibers can be produced industrially advantageously, and its usefulness is extremely large.

"Examples" The present invention will be explained in more detail below with reference to Examples and Comparative Examples. It is not limited.

The characteristic values in the following Examples and Comparative Examples were measured based on the following method.

The oxygen index is determined by taking 25 inches of filament with a total fineness of 5,400 denier, twisting it 75 times, combining two of them and twisting them 45 times to form a linear sample. The sample was heat-treated at 170° C. for 5 minutes and placed upright in the holder of an oxygen index sampler, and the percentage of oxygen required for the sample to continue burning for 5 cm was measured. The larger the oxygen index value, the more flame retardant. The oxygen index, its combustion state, and the sample after combustion were observed, and the flame retardancy and comprehensive evaluation of the fibers was performed according to the following criteria.

A: Very good B: Excellent C: Poor D: Poor The transparency of the fiber is determined by dissolving the fiber in dimethylformamide to form a 5% solution, and the light transmittance of the lea solution at a wavelength of 650 μm. was measured using a spectrophotometer and compared with the transmittance of dimethylformamide as 100.

The diameter of flame retardant particles in fibers containing tin oxide as the main component was observed using an electron microscope, and if the particles were agglomerated,
The average diameter of the particles was calculated.

The above-mentioned transmittance, particle size, glossiness and transparency of the fibers were observed, and the glossiness, transparency and overall evaluation of the fibers were performed according to the following criteria.

A: Very good B: Excellent C: Poor D: Poor Example 1 38 parts by weight of anhydrous tin tetrachloride was slowly mixed with 62 parts by weight of water in an acid-resistant container, and the mixture was decomposed by an ion exchange method. Hydrochloric acid was added to obtain an aqueous mixture containing 30% by weight of 5nOi and 24% by weight of HCi.

Note that the Snow concentration is expressed as the weight percent of the water-temperature hardware heated to dryness, and the HC1 concentration is expressed as the NaOH concentration obtained by further diluting the water mixture with water.
by neutralization titration.

Without drying 1 part by weight of the aqueous mixture containing tin oxide obtained as described above, 45% by weight of acrylonitrile was added.
, vinylidene chloride 34% by weight, vinyl chloride 20% by weight,
It was prepared by adding and mixing 100 parts by weight of a spinning stock solution containing 30% by weight of an acrylic copolymer consisting of 1% by weight of sodium styrene sulfonate and using acetone as a solvent.

This was discharged from a spinneret into an aqueous acetone solution, washed with water, stretched, and heat treated in a conventional manner to obtain a desired fiber. Table 1 shows various characteristic values of the obtained fibers.

The obtained fiber is! It has good flammability, gloss, and transparency, indicating that the specified tin oxide is contained in an extremely uniformly dispersed manner without agglomeration, and has excellent properties such as dyeability and dyeability, which are the basic properties of other fibers. It was also extremely good in dyeing devitrification, light resistance, and other physical properties, and maintained all quality levels except flame retardance of the fiber (Comparative Example 1) that did not contain tin oxide or the like.

Example 2 Wet grinding was carried out with 30 parts by weight of tin oxide, 671° C. parts of water, and 6 parts by weight of HCβ.

This tin oxide-containing aqueous mixture was added in an amount of 1 part by weight to 100 parts by weight of the spinning stock solution in the same manner as in Example 1 without drying.

The obtained fibers were stably produced without impairing the uniformity of the spinning dope, contained tin oxide with an average size of 0.2 μm, and had excellent gloss and flame retardancy.

Comparative Example 1 A fiber was obtained by spinning in the same manner as in Example 1, except that the aqueous mixture containing tin oxide and acid was not added. It was excellent in gloss and transparency, but inferior in flame retardancy.

Comparative Example 2 Commercially available mexuic acid was pulverized using a ball mill, and a small amount of diluted spinning stock solution was added and dispersed. This thing has an average of 0
．． It contained 30% by weight of tin oxide having a diameter of 45 μm, and as in Example 1, 1 part by weight was added to 100 parts by weight of the spinning dope.

The obtained fibers had excellent flame retardancy, but were inferior in gloss and transparency.

Table 1

Claims (1)

[Scope of Claims] 1. Spinning is carried out by adding and containing an aqueous mixture containing 10 to 50% by weight of tin oxide and an acid in an amount of 1/2 or less of the weight of the tin oxide to the spinning stock solution. A method for producing acrylic synthetic fibers. 2. The acid in the aqueous mixture is 1/100 to 1 of the weight of tin oxide
/3 amount of the manufacturing method according to claim 1: 3. Claim 1, wherein the acid in the aqueous mixture is hydrochloric acid.
Manufacturing method described in section. 4. Tin oxide with an average particle diameter of 0.1 μm or less
The manufacturing method according to claim 1, which contains 20% by weight. 5. The manufacturing method according to claim 1, wherein the acrylic synthetic fiber is mainly composed of an acrylonitrile copolymer copolymerized with 30 to 70% by weight of a halogen-containing vinyl monomer. 6. The acrylic synthetic fiber contains 30 to 70% by weight of halogen-containing vinyl monomers and 0% of sulfonic acid group-containing vinyl monomers.
．． The manufacturing method according to claim 5, wherein the main component is an acrylonitrile copolymer copolymerized in an amount of 1 to 10% by weight. 7. The manufacturing method according to claim 1, wherein the spinning dope is a spinning dope using an organic solvent as a solvent. 8. The manufacturing method according to claim 7, wherein the spinning dope is a spinning dope using acetone or acetonitrile as a solvent.