JP3370395B2 - Highly flame-retardant acrylic composite fiber - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a high flame retardancy,
The present invention also relates to an acrylic composite fiber having good mechanical properties such as good spinnability and processability. [0002] As a method for flame retarding acrylic fibers, flame retardant monomers such as vinyl chloride, vinylidene chloride and vinyl bromide are copolymerized with acrylonitrile to render the polymer itself flame retardant. Methods are known, and various flame-retardant acrylic fibers and modacrylic fibers have already been put on the market. Further, for applications requiring high flame retardancy such as curtains, metal oxides such as antimony trioxide and antimony pentoxide are further added as a flame retardant to the polymer constituting the acrylic fiber. Methods are known. However, Japanese Patent Application Laid-Open No. 63-126913
As disclosed in Japanese Unexamined Patent Publication, when antimony pentoxide is further added to a fiber made of a copolymer of acrylonitrile and vinylidene chloride to impart flame retardancy, the amount of addition is 4.0% or more. , The flame retardancy is saturated, and the effect of adding antimony pentoxide cannot be recognized. Further, Japanese Patent Publication No. 4-18050 discloses that
Acrylonitrile, vinyl chloride, vinylidene chloride, antimony trioxide is added to a fiber composed of a copolymer of sodium methallyl sulfonate from 8% by weight to 70% by weight, and a fiber composite with various fibers is produced. A comparison has been made between the flame retardancy of the fiber composite and the flame retardancy of the acrylic flame-retardant fiber alone, and when the content of antimony trioxide is set to a specific range and combined with cotton, the flame retardancy is reduced. No gender loss is disclosed. Further, Japanese Patent Laid-Open No. 5-78936 discloses that
If a large amount of antimony trioxide is added to the fiber to improve the flame retardancy, the spinnability and the mechanical properties of the fiber will be reduced. It is disclosed that a flame-retardant acrylic fiber that satisfies both performances of the mechanical properties cannot be obtained. That is, according to the publication, when the amount of the antimony compound added is in the range of 6% or more and less than 12%, the spinnability and the mechanical properties of the fiber are favorable, but the flame retardancy is low. On the other hand, it is disclosed that when the added amount of the antimony compound is in the range of 12 to 40%, the fiber has poor mechanical properties (yarn-forming properties) but can obtain a high degree of flame retardancy. [0008] JP-A-61-89339, JP-A-5-89339
The fiber composite described in -78936 is only when a fiber comprising a polymer containing halogen and cotton are composited,
This is an effective method. Therefore, development of a new flame-retardant acrylic fiber having high flame retardancy using acrylic fiber alone is desired. The present invention has been made in response to such a demand. SUMMARY OF THE INVENTION An object of the present invention is to provide an acrylic fiber having high flame retardancy and excellent mechanical properties such as good spinnability and processability. To be. The present invention relates to an acrylonitrile polymer (A) containing 30 to 50% by weight of vinyl chloride and / or vinylidene chloride, and a pentoxide having an average particle diameter of 200 nm or less in fiber. Antimony (B) and a monomer having at least one hydroxyl group in the monomer unit
It consists of three compounds of polymer (C) containing at a ratio of 0% by weight or more, and each of the three compounds is (A) 40 to 90
Parts by weight, (B) 1 to 30 parts by weight, and (C) 1 to 30 parts by weight, the total of which is 100 parts by weight, and the flame retardancy is measured according to JIS K7201A-1. A highly flame-retardant acrylic composite fiber characterized by having (LOI) of 34 or more. The acrylonitrile polymer (A) used in the present invention is a copolymer with acrylonitrile containing 30 to 50% by weight of vinyl chloride and / or vinylidene chloride. If the copolymerization amount of vinyl chloride and / or vinylidene chloride is less than 30% by weight, flame retardancy is undesirably reduced. On the other hand, when the content exceeds 50% by weight, the heat resistance and the clarity of dyeing of the obtained fiber are lowered, and further, the stiffness becomes weak, which is not preferable. The acrylonitrile-based polymer (A) may contain other copolymer components without departing from the object of the present invention. The other copolymerization component is not particularly limited and can be selected arbitrarily according to the purpose.For example, in order to improve dyeability, a sulfonic acid group-containing monomer is preferable. No. This copolymer component has a high effect of suppressing problems such as uneven dyeing in the dyeing step, and is preferably contained in the copolymer in an amount of 0.5 to 5% by weight. Specific examples of the sulfonic acid group-containing vinyl monomer include, for example, methallyl sulfonic acid, acrylic sulfonic acid, styrene sulfonic acid, vinyl benzene sulfonic acid, and salts thereof. Further, in order to improve the properties of the fiber, (meth)
It is possible to use unsaturated monomers copolymerizable with acrylonitrile such as unsaturated carboxylic acids such as acrylic acid, (meth) acrylic esters, (meth) acrylic amides, and vinyl esters such as vinyl acetate. is there. The spinning solvent for the acrylonitrile copolymer used for obtaining the highly flame-retardant conjugate fiber of the present invention is not particularly limited as long as it dissolves the polymer.
It can be arbitrarily selected according to the spinning technique and includes, for example, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like. In the present invention, 100 parts by weight of the acrylic composite fiber contains 1 to 30 parts by weight of antimony pentoxide (B) having an average particle diameter of 200 nm or less in the fiber and at least one hydroxyl group in the monomer unit. 50% by weight of monomer
It is necessary to contain 1 to 30 parts by weight of the polymer (C) contained in the above ratio. When antimony pentoxide is used as the antimony compound used in the present invention, higher flame retardancy can be obtained. Antimony pentoxide having an average particle diameter such that the average particle diameter in the fiber is 200 nm or less is used. 3 Constituting the Acrylic Composite Fiber of the Present Invention
If the content of antimony pentoxide (B) is less than 1 part by weight in the total of 100 parts by weight of the compound, sufficient flame retardancy cannot be obtained. The mechanical properties of Furthermore, nozzle clogging during spinning,
It may cause thread breakage. The polymer (C) containing at least 50% by weight of a monomer having at least one hydroxyl group in a monomer unit includes polyvinyl alcohol obtained by saponifying polyvinyl acetate. It is necessary that the polymer (C) contains 1 to 30 parts by weight based on 100 parts by weight of the acrylic composite fiber. When the content of the polymer (C) is less than 1 part by weight, the effect of improving the flame retardancy cannot be obtained. On the contrary, when the content exceeds 30 parts by weight, the mechanical properties of the obtained fiber and the dyeing inherent to the acrylic fiber The sharpness deteriorates. In the present invention, the reason that the flame retardancy is improved by containing the polymer (C) is that antimony trichloride formed in the combustion process from the contained antimony compound (antimony pentate) as described later. And the polymer (C) react with each other, and the polymer (C) is chlorinated. Therefore, the polymer (C) needs to react with antimony trichloride, and needs to have at least one hydroxyl group in a monomer unit. In the present invention, antimony pentoxide added to the fiber must be uniformly dispersed in the fiber. The average particle size of antimony pentoxide in the added fiber is determined by observing the fiber with a transmission electron microscope.
It is desirable that the thickness be not more than 00 nm. If the average particle size of antimony pentoxide in the fiber exceeds 200 nm, the mechanical properties of the fiber will be significantly reduced, possibly because the antimony pentoxide in the obtained fiber will be a defect point. Further, when the average particle diameter of antimony pentoxide in the fiber exceeds 200 nm, the flame retardancy is also reduced. As described above, in the present invention, it is extremely important that the very fine antimony compound is uniformly dispersed in the fiber. This can be achieved by the following method. . First, a colloidal dispersion of antimony pentoxide having an average particle diameter of 80 nm or less, which is obtained using the same organic solvent as the acrylonitrile-based polymer spinning solvent used in the present invention, is prepared. ), 100 parts by weight of a mixture comprising antimony pentoxide (B) and polymer (C), and a spinning solvent of 250 to 50
After mixing and diluting the colloid solution dispersion with the spinning solvent so as to be 0 parts by weight, the pH of the solution is adjusted to 5 to 6. The method of adjusting the pH is not particularly limited, and it can be appropriately selected from well-known ones such as a commercially available ordinary buffer according to the purpose. If the pH of the solution is lower than 5, antimony pentoxide is easily aggregated in the preparation process of the stock solution for spinning. Becomes Next, an acrylonitrile-based polymer (A) and a polymer (C) are added to the prepared solution and dissolved by heating to prepare a stock solution for spinning. In addition, heat dissolution is 60 ° C.
It is preferable to carry out at the following temperature. When the temperature is higher than 60 ° C., the polymer is liable to be thermally degraded, and the whiteness of the fiber is easily reduced. The target acrylic fiber is obtained by spinning the acrylic fiber by the known spinning method using the spinning stock solution prepared as described above. The spinning method is not particularly limited, and any one of dry spinning, wet spinning, and dry-wet spinning is selected according to the purpose. The acrylic fiber of the present invention has a single fiber fineness of 1.5 g / d, particularly preferably 2.5 g / d or more, even though it contains a large amount of antimony pentoxide as a flame retardant. It has excellent mechanical properties such as a fiber elongation of 25% or more, and even when it is compounded with other synthetic fibers or natural fibers, it is possible to obtain a fiber composite having high flame retardancy. . As described above, in the present invention, the highest flame retardancy is exhibited by using antimony pentoxide as the antimony compound. The reason is considered as follows. In the process of burning the polymer, OH radicals generated by the reaction between oxygen in the air and the polymer cause a chain reaction, and the burning of the polymer continues. However, if chlorine atoms are present in the polymer, the polymer itself generates hydrochloric acid by thermal decomposition, and this hydrochloric acid traps OH radicals, and exhibits a flame retardant effect, and the generated water enhances the flame retardant effect. . Also, if antimony pentoxide is present, antimony pentoxide forms a cycle consisting of antimony oxychloride and antimony trichloride,
In addition to enhancing the flame retardant effect, carbon dioxide generated by the reaction of antimony pentoxide with the polymer further improves the flame retardancy. Further, when a polymer (C) containing at least 50% by weight of a monomer having at least one hydroxyl group in a monomer unit coexists, antimony trichloride and the polymer (C) react, and a driving force is applied to this cycle. become. The flame retardant effect of the compound formed in this process can be classified as follows. The effect of diluting oxygen by producing water and carbon dioxide. Antimony trichloride gas of high specific gravity stays around combustibles, thereby suppressing the continuous reaction of combustion.
Hydrochloric acid and antimony trichloride trap OH radicals, thereby suppressing the chain reaction of combustion. Chlorination of polymer (C) by reaction of antimony trichloride with polymer (C). In this flame-retardant mechanism, it is necessary to efficiently convert antimony pentoxide to oxyantimony and antimony trichloride in order to improve the flame retardancy. In order to increase the reaction rate of antimony pentoxide, it is necessary to increase the contact area with the chlorine atom-containing polymer. To achieve this, the average particle size of antimony pentoxide in the fiber should be 2
Setting it to 00 nm is an effective means. The present invention will be specifically described below with reference to examples. The flame retardancy (LOI) was evaluated using a spun yarn obtained from the highly flame-retardant acrylic fiber of the present invention.
A knitted fabric of 00 g / m ² was created and JIS K7201A-
Measured according to No. 1. The reduced viscosity (ηred) of the polymer is
It was measured with a 0.5% dimethylformamide solution at 25 ° C. using a Cannon-Fenske viscometer. In the description, "parts" and "%" mean parts by weight and% by weight, respectively. Reference Examples 1 to 7 and Comparative Examples 1 to 5 Colloidal dispersion of dimethylacetamide (abbreviated as DMAc; the same applies hereinafter) having a pH of 5.2 and containing 40% of antimony pentoxide having an average particle diameter of 40 nm. DMAc
Was added and stirred and mixed for 1 hour to obtain a diluted colloidal dispersion having a pH of 5.6. To this colloidal dispersion, 70 parts of an acrylonitrile copolymer (ηred = 1.98) consisting of 57.5% of acrylonitrile, 40% of vinylidene chloride and 2.5% of sodium methallylsulfonate, cellulose diacetate ( (Acetylation degree 55%)) 15 parts were added and stirred and mixed. Next, the mixed solution was heated to 50 ° C.
The above polymer was dissolved to obtain a spinning dope. This spinning stock solution was prepared using a nozzle having a hole diameter of 100 μm and a number of holes of 3000,
DMAc / water = 40/60%, spun into a coagulation bath at 30 ° C., subjected to a desolvation treatment in hot water, stretched 6 times in boiling water, applied an oil agent, dried, and moistened with heat. A 2 denier acrylic fiber was obtained. Thereafter, similarly, as shown in Table 1, 11 kinds of acrylic fibers having different contents of acrylonitrile copolymer, antimony pentoxide and cellulose diacetate were obtained. Next, a knitted fabric was prepared from the spun yarn obtained using each of the above fibers, and the flame retardancy was evaluated. The results are shown in Table 1. The average particle size of antimony pentoxide in the fiber was measured by observing the fiber with a transmission electron microscope. [Table 1] As is clear from Table 1, high flame retardancy is obtained when an acrylonitrile copolymer, antimony pentoxide and cellulose diacetate coexist. In addition, it can be seen that even when the amount of antimony pentoxide added is increased to a considerable level, the resulting fibers have excellent mechanical properties. Comparative Example 6 The same procedure as in Example 1 was carried out except that an antimony trioxide dispersion having an average particle diameter of 300 nm was used, and the amount of antimony trioxide in 100 parts of the fiber constituting compound was 15 parts. Acrylic fiber was manufactured, and the flame retardancy was evaluated. The results obtained are shown in Table 1. [Reference Example 8], [Example 1], [Comparative Example 7] Triacetate instead of cellulose diacetate, a polymer containing at least 50% of a monomer having at least one hydroxyl group in a monomer unit ( An acrylic fiber was produced in the same manner as in Reference Example 1 except that C) and polymethyl methacrylate were used for comparison, and the flame retardancy was evaluated. Table 2 shows the obtained results. [Table 2] The fiber of the present invention has high flame retardancy,
In addition, it has good mechanical properties such as spinnability and processability. The flame-retardant fiber composite obtained by blending the acrylic fiber itself or other fibers has extremely high flame-retardant performance, so it can be used in a wide range of applications from the interior to the clothing field, and its significance. Is big.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadao Kobayashi 20-1 Miyukicho, Otake City, Hiroshima Prefecture Inside Mitsubishi Rayon Co., Ltd. Otake Works (72) Inventor Seimizo Oishi 20-1 Miyukicho, Otake City, Hiroshima Prefecture (56) References JP-A-56-309 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D01F 6/54

Claims (1)

(57) Claims 1. An acrylonitrile-based polymer (A) containing 30 to 50% by weight of vinyl chloride and / or vinylidene chloride, and antimony pentoxide having an average particle diameter of 200 nm or less in fiber ( B) and three types of polymer (C) containing at least 50% by weight of a monomer having at least one hydroxyl group in the monomer unit, wherein each of the three types of compounds is (A) 40 to 90 parts by weight. , (B) 1
30 parts by weight, and (C) coexisting in a range of 1 to 30 parts by weight so that the total amount becomes 100 parts by weight.
A highly flame-retardant acrylic composite fiber having a flame retardancy (LOI) of 34 or more measured according to No. 201A-1.