JP3217924B2 - Flame retardant rubber-modified polystyrene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-modified polystyrene resin composition, and more particularly, to a styrene resin composition having excellent flame retardancy and excellent heat resistance and impact resistance.

[0002]

2. Description of the Related Art Styrene resins are used in various fields because of their excellent moldability, mechanical properties and electrical properties. However, since it is flammable, it is necessary to make the resin flame-retardant when it is used for OA equipment, housing of home electric appliances and electric and electronic parts. The flame retardancy is regulated by UL standards and the like, and various measures for flame retardancy have been studied in recent years. Among them, in the field of housing for home appliances, the above flame retardant regulations and heat resistance,
Impact resistance and fluidity are required, and a well-balanced styrene-based resin that satisfies all these required properties is required.

[0003] In general, JP-A-58-187450 discloses that a styrene-based resin is made flame-retardant by using a high-melting-point halogen-based flame retardant such as decabromodiphenyl oxide in combination with antimony trioxide. ing. However, the drawbacks of this flame retardant are that the fluidity is reduced and the light resistance of the molded article is deteriorated. Further, in recent years, the toxicity of gas generated under certain conditions of the flame retardant has been taken up as an environmental problem.

JP-A-63-72749 discloses the use of a brominated bisphenol A type epoxy resin in combination with antimony trioxide. However, as a drawback of this flame retardant, when an amount of the flame retardant that gives satisfactory flame retardancy is added, impact resistance and heat resistance are remarkably reduced, and there is a problem in cost. Japanese Patent Application Laid-Open No. HEI 6 (1994) -1994 discloses that a polyhalogenated diphenylalkane and a brominated bisphenol A type epoxy resin are used in combination.
-73268, because the brominated bisphenol A type epoxy resin has a low halogen content,
In order to obtain the required flame retardancy, it is necessary to add a considerable amount of a halide, so that the impact resistance is reduced. Also,
The use of a brominated bisphenol A type epoxy resin as a combined flame retardant has the problem of further reducing heat resistance.

On the other hand, much research has been made on the addition of halogen-containing substances and polytetrafluoroethylene to resins.
JP-A-60-13844, JP-B-62-5882
9, JP-B-64-3900, JP-A-2-3
No. 2154, Japanese Patent Application Laid-Open No. 5-27531, etc., but in each case, the basic resin is a combination of a polycarbonate oligomer and an acrylonitrile-butadiene-styrene or a modified polyphenylene ether, and a polytetrafluoroethylene. Is for the purpose of reducing the melt-dropping properties of those resins. Japanese Patent Application Laid-Open No. 50-44121 discloses polystyrene.
However, there is a problem that the effect varies greatly depending on the type of halide to be added. Furthermore, if a polyhalogenated diphenylalkane is used as a polystyrene-based resin to make it flame-retardant, a large amount of non-melting solid must be added to the resin in order to obtain the desired flame-retardant performance. There was a problem.

[0006]

SUMMARY OF THE INVENTION The present invention provides a styrenic resin composition having excellent flame retardancy and a good balance of heat resistance and impact resistance.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a specific halogen-based flame retardant, a flame-retardant auxiliary and a small amount of polytetrafluoroethylene were added to polystyrene resin. Has been found to achieve the above object by reducing the amount of the specific halogen-based flame retardant added, thereby completing the present invention. That is, the present invention relates to (B) the following formula (1) based on 100 parts by weight of (A) rubber-modified polystyrene resin.
The polyhalogenated diphenylalkane represented by
20 parts by weight, (C) 1 to 10 parts by weight of antimony trioxide, and (D) polytetrafluoroethylene 0.01 to
It is a rubber-modified polystyrene resin composition obtained by adding 0.5 part.

[0008]

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In the formula, X represents a bromine atom or a chlorine atom, l and m each represent an integer of 0 to 5 (provided that 1 and m are not 0 at the same time), and R is C _n H. _2n (n = 1
10 to 10). Hereinafter, the present invention will be described in detail. The rubber-modified polystyrene-based resin (A) used in the present invention refers to a polymer obtained by dispersing a rubber-like polymer in the form of particles in a matrix composed of a vinyl aromatic polymer, and is generally a rubber-like polymer. Is dissolved in a vinyl aromatic monomer (and a liquid to which an inert solvent is added), and bulk polymerization, bulk suspension polymerization or solution polymerization is carried out with stirring to obtain a rubbery polymer, which is obtained by precipitation and granulation. However, the present invention is not limited to the polymerization method.

The above-mentioned vinyl aromatic monomers include, in addition to styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene,
Nuclear alkyl-substituted styrenes such as ethylstyrene and p-tert-butylstyrene, and α-alkyl-substituted styrenes such as α-methylstyrene and α-methyl-p-methylstyrene can be mentioned. It is. These may be used in combination of two or more thereof.

Examples of the rubbery polymer include polybutadiene, styrene / butadiene copolymer, polyisoprene, butadiene / isoprene copolymer, natural rubber, and ethylene / propylene copolymer.
Generally, polybutadiene and styrene / butadiene copolymer are preferred. The weight-average molecular weight of the matrix portion of the rubber-modified vinyl aromatic resin constituting the resin composition of the present invention is generally adjusted to a range of 15 × 10 ⁴ or more from the relationship of strength. Decreases rapidly.

The content of the rubber-like polymer in the rubber-modified polystyrene resin is not particularly limited, but is generally 4 to 4.
It is 15% by weight, more preferably 6 to 12% by weight. Further, the average particle size of the rubber particles in the rubber-modified vinyl aromatic resin is controlled in the range of 0.5 to 6 μm. The gel content of the rubber-modified polystyrene resin (toluene-insoluble matter)
Is usually adjusted to 15 to 40% by weight, more preferably 20 to 35% by weight.

Next, the polyhalogenated diphenylalkane (B) in the present invention is represented by the above general formula (1). Specific examples of the halogen-substituted phenyl group include dibromophenyl, tribromophenyl, tetrabromophenyl,
Examples include pentabromophenyl, dichlorophenyl, trichlorophenyl, tetrachlorophenyl, pentachlorophenyl and the like.

Polyhalogenated diphenylalkane (B)
Although the method for producing is not particularly limited, for example, JP-A-2-42031 or JP-A-6-73268
Alternatively, a device manufactured by the method described in Japanese Patent Application Laid-Open No. H10-206 may be used. As the polyhalogenated diphenylalkane used in the present invention, commercially available ones can be used,
For example, Saytex 8010 of Albemarle Co. of the United States can be mentioned.

Further, antimony trioxide which is the component (C) of the present invention acts as a flame retardant aid. (A)
The mixing ratio of these to 100 parts by weight of the polystyrene resin is such that the polyhalogenated diphenylalkane is 12 to 2 parts.
0 parts by weight and polytetrafluoroethylene is 0.01 to
0.5 parts by weight and 1 to 10 parts by weight of antimony trioxide are required. More preferably, the polyhalogenated diphenylalkane is 12 to 15 parts by weight, the polytetrafluoroethylene is 0.05 to 0.1 part by weight, and the antimony trioxide is 3 to 7 parts by weight.

The flame-retardant resin composition of the present invention can be obtained by blending these components in predetermined amounts, and the blending method is not particularly limited, and includes a Henschel mixer, a tumbler mixer, a super mixer, a Banbury mixer, a kneader, A roll, a single screw extruder, a twin screw extruder, or the like can be used. In the composition of the present invention, other additives such as a chlorine compound, a bromine compound, a plasticizer, a lubricant, a stabilizer, a UV absorber, a filler, a colorant, and a reinforcing agent are provided as long as the object of the present invention is not impaired. Agents and the like can be added.

[0017]

The present invention will be described below with reference to examples and comparative examples. The measuring methods and evaluation methods used in the examples and comparative examples are shown below. (1) Izod impact strength: Measured according to ASTM-D256 at 23 ° C. using a notched specimen. (2) Flexural modulus: measured according to ASTM-D790. (3) Vicat softening point: measured by ASTM-D1525. (4) Fluidity: Melt flow rate is ASTM-D12
38. (5) Flammability: Underwriters Laboratories, Inc. (Underwriters, USA)
Laboratories Inc. , U.S. S. 94A described in 7 to 10 items of "UL94 Safety Standard: Burning Test of Plastic Materials for Equipment Parts" published by A)
-2, 94V-1, 94V-0 (hereinafter, "V-2",
Abbreviated as "V-1" or "V-0". ).

[0018]

Examples 1 to 5 A compound represented by the following formula 3 (trade name: Saytex 8) as a polyhalogenated diphenyl alkane was added to 100 parts by weight of a rubber-modified polystyrene resin.
010 Albemarle), antimony trioxide, and polytetrafluoroethylene (trade name: F104, manufactured by Daikin Industries, Ltd.) at the ratios shown in the table, and melt-kneading with a twin-screw extruder (cylinder setting). (Temperature 200 ° C)
After injection molding (cylinder temperature 200 ° C, mold temperature 60
C.) to form a molded piece. Using this test piece, Izod impact strength, flexural modulus, Vicat softening point, fluidity, and flammability were measured. Table 1 shows the results. However, the unit of the mixing ratio shown in the table is part by weight.
The resin exhibits satisfactory values of Izod impact strength, flexural modulus, Vicat softening point, and melt flow rate as a resin, and has flame retardancy rated as V-0 up to the desired thinness in terms of flammability.

[0019]

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[0020]

Comparative Examples 1-2 The physical properties were measured in the same manner as in the Examples except that polytetrafluoroethylene was not used, and the results are shown in Table 2. Unless polytetrafluoroethylene is used, even the intended thin wall does not have the flame retardancy rated as V-0. Also, increasing the addition amount of polyhalogenated diphenylalkane (trade name: Saytex 8010 manufactured by Albemarle Co.) until the desired thinness has the flame retardancy of V-0, the desired Izod impact strength can be obtained. Absent.

[0021]

Comparative Examples 3 to 5 Physical properties were measured by the same procedures as in the examples and are shown in Table 2. If the amount of polytetrafluoroethylene (trade name: F104, manufactured by Daikin Industries, Ltd.) is small, the desired thin wall does not have the flame retardancy rated as V-0. When the amount of polytetrafluoroethylene added is large, the glowing after the flame is extinguished does not stop within the specified time, and is not ranked V-0 according to the definition of UL94. Similarly, if the addition amount of the polyhalogenated diphenylalkane is small, it does not have the flame retardancy ranked as V-0.

[0022]

Comparative Examples 6 and 7 A brominated bisphenol A epoxy resin (trade name: EC20, manufactured by Dainippon Ink) and commonly available tetrabromobisphenol A were used in place of the polyhalogenated diphenylalkane in the same manner as in the examples. The physical properties were measured and are shown in Table 2. Neither bromo compound has the flame retardancy of V-0 even if polytetrafluoroethylene is added, even to the desired thin thickness.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

The resin composition of the present invention has a good balance of heat resistance, impact resistance, and fluidity while reducing the amount of a specific halogen-based flame retardant to be added and having excellent flame retardancy. Things. Therefore, the resin composition of the present invention is particularly required for flame retardant fields, specifically, home appliances, office equipment,
It is expected to be used effectively for housings of information equipment.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 51/04 C08K 3/22 C08K 5/03 C08L 27/18

Claims (1)

(57) [Claims] (A) a rubber-modified polystyrene resin 10
(B) 12 to 20 parts by weight of a polyhalogenated diphenylalkane represented by the following formula (1) based on 0 parts by weight;
A rubber-modified polystyrene resin composition comprising (C) 1 to 10 parts by weight of antimony trioxide and (D) 0.01 to 0.5 part by weight of polytetrafluoroethylene. Embedded image [Wherein, X represents a bromine atom or a chlorine atom, l and m each represent an integer of 0 to 5 (provided that 1 and m are not simultaneously 0), and R is C _n H _2n (n = 1 to 10). ]