JPH1160854A - Styrene resin composition and electrical or electronic appliance housing made therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in the appearance of a molding and in heat stability during molding by mixing a styrene resin with an organic fiber having a specified fiber diameter and a specified fiber length and a dispersant in a specified ratio. SOLUTION: One hundred pts.wt. styrene resin is mixed with 0.1-2 pts.wt. organic fiber having a fiber diameter of 5-100 μm and a fiber length of 0.01-2 mm and 0.1-3 pts.wt. dispersant. The styrene resin is obtained for example by dissolving a rubbery polymer (e.g. polybutadiene) in a vinylaromatic monomer (e.g. styrene) in the presence of a comonomer (e.g. acrylonitrile), subjecting the solution to bulk polymerization or the like to deposit the rubbery polymer on the matrix. The organic fiber used is desirably for example rayon, polyester and nylon fibers. The dispersant is exemplified by a higher fatty acid, its metal salt or an fatty acid ester. The flame retardant used is exemplified by a bromine-containing flame retardant (e.g. brominated bisphenol epoxy polymer).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel styrenic resin composition and a molded article using the same.
More specifically, the present invention relates to a styrenic resin composition having excellent molding appearance and thermal stability at the time of molding, and a housing for electric or electronic equipment products using the same as a molding material.

[0002]

2. Description of the Related Art Hitherto, styrene resins such as polystyrene and ABS resin have been used in many fields because of their excellent moldability, mechanical strength and electrical properties. Surface coating is usually performed on electric or electronic equipment housings such as those described above to compensate for poor appearance during molding and improve light resistance.

[0003] However, surface coating results in an increase in the number of working steps, and the presence of a coating film makes recycling difficult when recycling products for environmental protection. Therefore, in recent years, there has been an increasing demand for unpainted electrical or electronic equipment housings in order to recycle products and reduce costs. However, since the problems of poor appearance of the weld portion and poor thermal stability at the time of molding (specifically, generation of silver) have not been solved, it is practically difficult to remove the coating.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in a styrenic resin composition molded article, and provides a styrenic resin composition having improved weld appearance and heat stability at the time of molding. It is an object of the present invention to provide an electric or electronic equipment housing that can be made unpainted by using an electronic component.

[0005]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found that this problem can be solved by using a specific organic fiber and a dispersant, and furthermore, a flame retardant and a flame retardant auxiliary agent. By adding a specific amount of, it is found that the composition is also excellent in flame retardancy and various physical properties,
Based on this knowledge, the present invention having the following contents has been completed.

(1) 100 parts by weight of (A) styrene resin, (B) 0.1 to 2 parts by weight of organic fibers having a fiber diameter of 5 to 100 microns and a fiber length of 0.01 to 2 mm,
(C) A styrenic resin composition containing 0.1 to 3 parts by weight of a dispersant. (2) The styrene resin composition according to (1), wherein the (B) organic fiber is a rayon-based, polyester-based or nylon-based fiber. (3) The styrene resin composition according to (1) or (2), wherein (C) the dispersant is a higher fatty acid or a metal salt thereof. (4) 100 parts by weight of styrene resin, (D) 3 to 30 parts by weight of flame retardant and (E) 2 to 3 parts by weight of flame retardant
The styrenic resin composition according to any one of (1) to (3), wherein 10 parts by weight are blended. (5) The styrene according to (4), wherein (D) the flame retardant is at least one of a brominated bisphenol-type epoxy polymer, a polyhalogenated diphenylalkane, a brominated triazine, and a polymethylphenylindene flame retardant. -Based resin composition. (6) A housing for an electric or electronic device product obtained by molding the styrene resin composition according to any one of (1) to (5).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The styrenic resin (A) used in the present invention is not particularly limited, and is a known method, for example, a method in which a vinyl aromatic monomer is polymerized alone or in the presence of a comonomer, or various rubbery polymers are dissolved therein. By performing bulk polymerization, bulk suspension polymerization, suspension polymerization, etc., to obtain a polymer obtained by precipitating a rubber-like polymer in a vinyl aromatic polymer alone or in a matrix,
Obtained by forming particles. As the vinyl aromatic monomer used here, styrene, o-methylstyrene,
α-alkyl-substituted styrenes such as p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, nucleated alkyl-substituted styrenes such as p-tert-butylstyrene, α-methylstyrene and α-methyl-p-methylstyrene And the like. Among them, styrene can be suitably used.

[0008] As comonomer, acrylonitrile,
And maleic anhydride. Examples of the rubbery polymer include various conjugated diene compounds such as polybutadiene, styrene / butadiene copolymer, polyisoprene, and natural rubber. Among them, polybutadiene and styrene / butadiene copolymer can be preferably used. Specifically, the styrene-based resin is homopolystyrene, polyparamethylstyrene, rubber-modified polystyrene, ABS resin, AS resin, MBS resin, AES resin, etc., and rubber-modified polystyrene can be particularly preferably used. When rubber-modified polystyrene is used, the weight average molecular weight of the matrix component is 80,000 to 35.
It is preferable from the viewpoint of the physical properties of the product that the content of the rubber is adjusted to 0000 and the amount of the rubber added to 5 to 20% by weight.

(B) Any organic fiber having a predetermined fiber diameter and fiber length can be used without any particular limitation. Specifically, cotton, silk, kabok, wool, flax, hemp, lami , Jute, natural fiber such as coconut, polyester, nylon, polyacetal, polyurethane, polyethylene, polyvinyl chloride, acrylic, aramid, etc., semi-synthetic fiber such as acetate, rayon, vinylon, etc. And recycled fibers can be used alone or in combination.

Of these, rayon-based, polyester-based, and nylon-based fibers are preferred because they are easily available for general use and easily obtain required characteristics. In addition,
Fibers such as yong, vinylon, polyester, acetate and the like exhibit a silky coloring by stretching, and can be used to give a pearl-like color tone.
Further, by dyeing a yarn such as jute or using a matting yarn, a matte color tone can be obtained on a molded product.

In the present invention, such an organic fiber needs to have a fiber diameter of 5 to 100 microns and a fiber length of 0.01 to 2 mm. Here, the fiber diameter refers to the maximum diameter in the fiber cross section. A fiber having a fiber diameter or a shorter fiber length smaller than this range is not preferable because the molded article is easily damaged, and a fiber having a fiber diameter or a longer fiber length larger than this range has a good appearance of the molded article and a good appearance. I can't. The addition amount is 0.1 to 2 parts by weight based on 100 parts by weight of the styrene resin. If the amount is less than 0.1 part by weight, the effect of improving the appearance of the weld cannot be obtained.

(C) The dispersant is not particularly limited as long as it is an additive which generally has an effect of improving the dispersibility of other additives (organic fibers and the like) in the styrene resin. Salt, fatty acid ester, fatty acid amide, higher alcohol, mineral oil, polyethylene wax,
Polyethylene glycol and the like. Preferred are higher fatty acids and / or metal salts thereof, and more preferable are zinc, magnesium, calcium and barium metal salts of higher fatty acids.

These dispersants can be used alone or in combination of two or more, and the amount added is in the range of 0.1 to 3 parts by weight based on 100 parts by weight of the styrene resin. If the amount of such a dispersant is less than 0.1 part by weight, it becomes difficult to prevent entanglement of the fibers, and a good appearance cannot be obtained. If the amount exceeds 3 parts by weight, poor appearance due to silver tends to occur due to poor thermal stability during molding. In the present invention, particularly when flame retardancy is required, (D) a flame retardant and (E) a flame retardant auxiliary are further blended. As the flame retardant (D), a halogen-based flame retardant is preferably used for the purpose of satisfying the flame retardant regulations such as UL standards. Representative examples of the halogen-based flame retardant include a chlorine-based flame retardant, a bromine-based flame retardant, and a fluorine-based flame retardant. Among them, the chlorine-based flame retardant and the brominated flame retardant are more preferred, and the brominated flame retardant is most preferred. Used for

Usually, brominated flame retardants include brominated bisphenol type epoxy polymer, polyhalogenated diphenylalkane, brominated triazine flame retardant, polymethylphenylindene flame retardant, tetrabromobisphenol A
Etc. can be given. Examples of the chlorine-based flame retardant include perchlorocyclopentadecane, chlorinated paraffin and the like. In the present invention, brominated bisphenol-type epoxy polymers, polyhalogenated diphenylalkanes, and brominated triazines as specific halogen-based flame retardants are used. At least one kind of flame retardant selected from a series flame retardant and a polymethylphenylindene flame retardant is preferably used.

The compounding amount is 3 to 30 parts by weight, preferably 10 to 25 parts by weight, per 100 parts by weight of the styrene resin.
Parts by weight. If the compounding amount of the flame retardant is less than 3 parts by weight, the intended effect of improving the flame retardant becomes insufficient.
If the amount exceeds the weight part, the light resistance and impact resistance of the molded product are reduced, and the appearance is deteriorated.

(E) The flame retardant aid is used for improving the flame retardant effect of the flame retardant. Specifically, antimony trioxide,
In addition to antimony-based flame retardants such as antimony tetroxide, antimony pentoxide, sodium antimonate, metal antimony, antimony trichloride, and antimony pentachloride, barium metaborate, zirconium oxide, zinc borate, zinc stannate, etc. be able to. These flame retardant aids can be used alone or in combination of two or more. Among these, antimony trioxide can be particularly preferably used.

The compounding amount is 2 to 10 parts by weight based on 100 parts by weight of the styrene resin. If the amount is outside the above range, the effect of improving the flame retardancy of the flame retardant auxiliary is not observed. In the flame-retardant resin composition of the present invention, other additives within a range that does not impair the purpose of the present invention, for example, a lubricant, a plasticizer, an antistatic agent, an antioxidant, an ultraviolet absorber, a filler, a reinforcing agent, Pigments, colorants and the like can be added.

The pellets of the resin composition of the present invention are:
The above components can be melt-kneaded using a Henschel mixer, a twin-screw extruder, or the like, and can be manufactured by a pelletizer. TV, video player, stereo recorder / player, radio, car-mounted navigator, telephone, mobile phone, refrigerator, air conditioner, vacuum cleaner, lighting fixture, computer Thus, a housing for an electric or electronic device product is obtained.

[0019]

Next, the present invention will be described with reference to Examples and Comparative Examples. [Examples 1 to 10, Comparative Examples 1 to 6] The components shown in Tables 1 and 3 were mixed in a Henschel mixer, melt-kneaded in a twin-screw extruder, pelletized, and injection-molded. Various test pieces were prepared. The evaluation results of these test pieces are shown in Table 2 and 4.

The following were used as components of the composition. (1) Resin (a) Rubber-modified styrenic polymer (hereinafter “PS”) (high impact polystyrene, molecular weight 200,000, rubber content 8% by weight, rubber particle size 2 μm) , IDEMITSU PS HT52) (2) Fiber filler (a) Rayon fiber (fiber diameter 50 μm, dyed with Nippon Kayaku Bull-RS, 1 mm length, manufactured by Daiwa Spinning) (hereinafter “Fiber Filler-1”) ( b) Rayon fiber (fiber diameter 50 μm, dyed with Nippon Kayaku Bull-RS, 0.05 mm length, manufactured by Daiwa Spinning) (hereinafter “fiber filler-2”) (c) rayon fiber (fiber diameter 50 μm) Dyed with Nippon Kayaku Bull-RS, 3 mm length, manufactured by Daiwa Spinning Co., Ltd. (hereinafter, “Fiber Filler-3”) (d) Rayon fiber (fiber diameter: 1 μm, dyed with Nippon Kayaku Blue-RS, 1 mm length, Daiwa Spinning) Weifiller-4 ") (e) Rayon fiber (fiber diameter 150 µm, dyed with Nippon Kayaku Blue-RS, 1 mm long, manufactured by Daiwa Spinning) (hereinafter" fiber filler-5 ") (f) Polyester fiber ( Fiber diameter 50 μm, dyed with Nippon Kayaku Bull-RS, 1 mm length, made by Unitika Ltd. (hereinafter “fiber filler-6”) (g) Polyester fiber (fiber diameter 50 μm, dyed with Nippon Kayaku Blue-RS, 3 mm (Hereinafter, "Fiber Filler-7") (3) Dispersant (a) Zinc stearate: Nippon Oil & Fat (hereinafter "St-Zn") (4) Flame retardant (a) Brominated bisphenol Type epoxy polymer (hereinafter "flame retardant P") (EC-14 manufactured by Dainippon Ink and Chemicals, Inc.) (b) polyhalogenated diphenylalkane (hereinafter "flame retardant Q") (Saytex 8010 manufactured by Albemarle) (c) ) Bromination Triazine-based flame retardant (hereinafter “flame retardant R”) (Daiichi Kogyo Seiyaku Co., Ltd. SR-245) (d) Polymethylphenylindene-based flame retardant (hereinafter “flame retardant S”) (DSB FR-1808) ( 5) Flame retardant aid (a) Antimony trioxide (hereinafter "Sb203") Evaluation of flame retardancy and the like was performed by the following method. (1) Flame retardancy The obtained test piece (dimension 127 mm x 13 mm x 2.5 m
m) was evaluated in accordance with the UL-94 standard. (2) General physical properties The obtained test pieces were measured for flexural modulus, Izod impact value and heat deformation temperature according to JIS K7203 and K
It was measured according to 7110 and K7207. (3) Weld Appearance The compositions shown in Tables 1 and 3 were manufactured by injection molding into box-shaped multipoint gates, and the merging weld portion of the resin was evaluated in two levels of good and bad.

(〇: good, ×: not good) (4) Evaluation of Thermal Stability A pellet of the melt-kneaded resin composition was placed in an injection molding machine for 220 minutes.
After holding at 20 ° C. for 20 minutes, a plate-like molded product of 40 × 110 mm was molded, and the degree of silver generation was visually evaluated in two stages of good and bad.

(〇: good, ×: bad)

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

The resin composition of the present invention is excellent in appearance and heat stability at the time of molding by using a specific organic fiber and a dispersant. Suitable for painting. Further, by using a specific amount of the flame retardant and the flame retardant auxiliary, a molded article having a good balance between flame retardancy and other physical properties (impact strength, heat resistance, etc.) can be obtained.

Claims (6)

[Claims] 1. A fiber having a fiber diameter of 5 to 100 microns and a fiber length of 0.1 to 100 parts by weight of a styrene resin (A).
0.1 to 2 parts by weight of organic fiber of 01 to 2 mm, and (C)
A styrenic resin composition containing 0.1 to 3 parts by weight of a dispersant. 2. The styrenic resin composition according to claim 1, wherein (B) the organic fiber is a rayon-based, polyester-based or nylon-based fiber. 3. The styrenic resin composition according to claim 1, wherein (C) the dispersant is a higher fatty acid or a metal salt thereof. 4. The composition according to claim 1, further comprising (D) 3 to 30 parts by weight of a flame retardant and (E) 2 to 10 parts by weight of a flame retardant aid per 100 parts by weight of the styrene resin. The styrenic resin composition according to any one of the above. 5. The flame retardant of claim 4, wherein the flame retardant is at least one of a brominated bisphenol type epoxy polymer, a polyhalogenated diphenylalkane, a brominated triazine, and a polymethylphenylindene flame retardant. Styrene resin composition. 6. A housing for an electric or electronic device product obtained by molding the styrene resin composition according to claim 1.