JPH10265643A - Flame-retardant thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition excellent in flame retardancy, impact resistance, rigidity, heat resistance and moldability with good balance among them, excellent particularly in the flame retardancy and falling ball impact strength of its thin-wall molding, and suitable for thin-wall moldings by blending a rubber-toughened styrene resin with an organophosphorus compound, and an inorganic phosphorus compound selected from ammonium polyphosphate and red phosphorus each in a specified amount. SOLUTION: A rubber-toughened styrene resin (A) in an amount of 100 pts.wt. is blended with an organophosphorus compound (B) represented by the formula [X is arylene; and R<1> to R<4> are each a (substituted) phenyl], and an inorganic phosphorus compound (C) selected from ammonium polyphosphate and red phosphorus in such a manner that the weight ratio of component B to component C is (95:5) to (50:50) and that the total content of phosphorus atoms of component B and component C is 1.2-8.0 pts.wt. based on the component A. The component A contains both a graft copolymer obtained by grafting a (co)polymer containing styrene monomer with a rubbery polymer, and a (co)polymer containing styrene monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent flame retardancy, impact resistance, rigidity, heat resistance, and moldability, and is particularly excellent in flame retardancy and impact of falling weight in thin-wall molding. The present invention relates to a thermoplastic resin composition suitable for a product.

[0002]

2. Description of the Related Art Plastics have excellent mechanical properties,
Due to its moldability and electrical insulation, it is used in a wide range of fields including home electric appliances, OA appliances, automobiles and other parts. However, in recent years, most of plastics used in such fields are flammable, and there is an increasing demand for flame retardancy due to safety issues, and various flame retardant technologies have been devised.

[0003] Generally, a method is employed in which a halogen-based flame retardant such as a bromine compound having a high flame-retardant efficiency and antimony oxide are blended with a resin to make the resin flame-retardant. However, the use of flame retardants that do not contain chlorine and bromine has become highly desirable due to environmental impact.

Heretofore, as a method of making a thermoplastic resin flame-retardant without using a chlorine or bromine-based flame retardant, a method of blending red phosphorus and a metal oxide with a styrene resin (Japanese Patent Laid-Open No.
No. 106140) and a method of blending red phosphorus and an organic phosphorus compound (Japanese Patent Laid-Open No. 4-106142), a polyhydroxy compound such as ammonium polyphosphate and pentaerythritol and a silane coupling agent in a rubber-reinforced polystyrene resin. (Japanese Patent Laid-Open No. 5-140)
412), a method in which melamine-coated ammonium polyphosphate and a specific nitrogen-containing organic compound are blended in a thermoplastic resin (JP-A-6-340815), and a method in which a small amount of a phenol resin and a flame retardant are blended in a thermoplastic resin. (JP-A-7-53879) and the like have been proposed.

[0005]

However, in the method using a halogen-based flame retardant, the flame retardant is added in an increased amount in order to prevent the drip of a fire during combustion, so that the mechanical properties and heat resistance of the resin composition are reduced. However, there is a problem that gas is generated by decomposition of the halogen compound during molding or combustion.

Further, the composition disclosed in JP-A-4-106140 has poor impact resistance and molding processability.
The composition described in JP-B-142 is not satisfactory because of its poor heat resistance.

The composition described in Japanese Patent Application Laid-Open No. 5-140412 has poor impact resistance and molding processability, and the use of a polyvalent alcohol compound causes mold contamination during molding and stickiness due to moisture absorption of molded products. However, the compositions described in JP-A-6-340815 and JP-A-7-53879 have a poor balance between impact resistance, moldability and flame retardancy in styrene resins. Thus, these did not satisfy various properties.

The present invention is a resin which is excellent in flame retardancy, impact resistance, rigidity, heat resistance and molding processability, and is particularly excellent in flame retardancy and falling weight impact with a thin wall and suitable for a thin wall molded article. It is intended to provide a composition.

[0009]

The present invention has been made as a result of intensive studies to solve the above-mentioned problems, and as a result, an organic phosphorus compound specific to rubber-reinforced styrene resin and ammonium polyphosphate and / or
Or, by blending a specific amount of a mixture obtained by mixing red phosphorus in a specific ratio, the present inventors have found that the flame retardancy and heat resistance with excellent drip properties, the moldability, and the thin falling weight impact are remarkably excellent. . That is, the present invention provides "(A) 100 parts by weight of a rubber-reinforced styrene resin, (B) an organic phosphorus compound represented by the general formula (I), (C) ammonium polyphosphate, or red phosphorus. The ratio of the at least one inorganic phosphorus compound is 95: 5 to 50:50 (weight ratio), and the total phosphorus atom content of the component (B) and the component (C) is 100 parts by weight of the component (A). In contrast, 1.2 to 8.0
Parts by weight of a flame-retardant thermoplastic resin composition ".

[0010]

Embedded image (In the formula, X is an arylene group, and R ¹ , R ² , R ³ , and R ⁴ are a substituted or unsubstituted phenyl group.)

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below. The weight in the present invention means mass.

The rubber-reinforced styrenic resin (A) in the present invention has a structure in which a (co) polymer containing a styrene monomer is grafted to a rubbery polymer, and a resin containing a styrene monomer. It also includes those having a structure in which the (co) polymer is not grafted to the rubbery polymer.

More specifically, 95 to 20 parts by weight of a monomer or monomer mixture containing (a1) an aromatic vinyl monomer in an amount of 20% by weight or more per 5 to 80 parts by weight of a rubbery polymer (b) (A1) 5 to 100% by weight of a graft (co) polymer obtained by graft polymerization and (a2) a monomer or monomer mixture containing at least 20% by weight of an aromatic vinyl monomer. (A2) vinyl-based (co) polymer 0 to 95
% By weight is preferred.

As the rubbery polymer (b), those having a glass transition temperature of 0 ° C. or less are preferred, and diene rubbers are preferably used. Specifically, diene rubbers such as polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene block copolymer, butyl acrylate-butadiene copolymer, and acrylics such as polybutyl acrylate Rubber, polyisoprene, ethylene-propylene-diene terpolymer and the like. Among them, polybutadiene or butadiene copolymer is preferred.

Although the rubber particle diameter of the rubbery polymer is not particularly limited, the weight average particle diameter of the rubber particles is 0.15 to 0.6.
Those having a thickness of 0 μm, particularly 0.2 to 0.55 μm, are preferable because of excellent impact resistance. Among them, (b1) 0.20 to 0.25μ
m and (b2) the weight ratio of 0.50 to 0.65 μm is 9
Those having a ratio of 0:10 to 60:40 are preferable because the impact resistance and the falling weight impact of a thin molded product are remarkably excellent.

The weight average particle diameter of the rubber particles of the rubbery polymer can be determined by a sodium alginate creaming method (Rubber Age Vol. 88).
p. 484-490 (1960) by E.E. Schm
idt, P .; H. Bidison).

As the aromatic vinyl monomer, styrene,
Examples include α-methylstyrene, vinyltoluene, o-ethylstyrene, pt-butylstyrene, etc., with styrene being particularly preferred.

As the monomer other than the aromatic vinyl monomer, a vinyl cyanide monomer is used for the purpose of further improving impact resistance, and a (meth) acrylic monomer is used for the purpose of improving toughness and color tone. Acid ester monomers are preferably used. Examples of the vinyl cyanide-based monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, and acrylonitrile is particularly preferable. Examples of the (meth) acrylate-based monomer include methyl and ethyl esters of acrylic acid and methacrylic acid with ethyl, propyl, n-butyl and i-butyl. Particularly, methyl methacrylate is preferred.

If necessary, other vinyl monomers,
For example, maleimide monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide can be used.

(A1) The monomer or monomer mixture used in the graft copolymer is an aromatic vinyl monomer 2
It is at least 0% by weight, preferably at least 50% by weight. When the proportion of the aromatic vinyl monomer is less than 20% by weight, the impact resistance of the resin composition is poor, which is not preferable. When a vinyl cyanide monomer is mixed, the amount is preferably 60% by weight or less, and more preferably 50% by weight or less, from the viewpoint of moldability of the resin composition. When a (meth) acrylate-based monomer is mixed, the amount is preferably 80% by weight or less, more preferably 75% by weight or less from the viewpoint of toughness and impact resistance. The total amount of the aromatic vinyl-based monomer, vinyl cyanide-based monomer and (meth) acrylate-based monomer in the monomer or the monomer mixture is 95 to 20% by weight, more preferably 90-3
0% by weight.

(A1) The ratio of the rubbery polymer to the monomer mixture in obtaining the graft copolymer is 5 parts by weight or more, preferably 10 parts by weight, of the rubbery polymer based on 100 parts by weight of the total graft copolymer. Not less than 80 parts by weight, preferably not more than 70 parts by weight, is used. The monomer or monomer mixture is 95 parts by weight or less, preferably 90 parts by weight or less,
Also, it is at least 20 parts by weight, preferably at least 30 parts by weight. If the proportion of the rubbery polymer is less than 5 parts by weight, the impact resistance of the resin composition is inferior, and if it exceeds 80 parts by weight, the impact resistance of the resin composition and the appearance of a molded product are undesirably impaired.

(A1) The graft copolymer can be obtained by a known polymerization method. For example, it can be obtained by a method in which a mixture of a monomer and a chain transfer agent and a solution of a radical generator dissolved in an emulsifier are continuously supplied to a polymerization vessel in the presence of a rubbery polymer latex to carry out emulsion polymerization.

(A1) The graft copolymer contains a non-grafted copolymer in addition to a material having a structure in which a monomer or a monomer mixture is grafted on a rubbery polymer. . (A) The graft ratio of the graft copolymer is not particularly limited, but is preferably 20 to 80% by weight, particularly 25 to obtain a resin composition excellent in impact resistance and gloss.
~ 50% by weight is preferred. Here, the graft ratio is calculated by the following equation.

Graft ratio (%) = <amount of vinyl copolymer graft-polymerized on rubbery polymer> / <rubber content of graft copolymer> × 100

The properties of the ungrafted copolymer are not particularly limited, but the intrinsic viscosity [η] (measured at 30 ° C.) of the methyl ethyl ketone-soluble component is 0.25 to 0.60.
dl / g, especially in the range of 0.25 to 0.50 dl / g,
Since a resin composition having excellent impact resistance can be obtained, it is preferably used.

(A2) The vinyl (co) polymer is a copolymer essentially containing an aromatic vinyl monomer. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene, vinyltoluene, o-ethylstyrene, and the like, with styrene being particularly preferred. One or more of these can be used.

As a monomer other than the aromatic vinyl monomer, a vinyl cyanide monomer is preferably used for the purpose of further improving impact resistance. For the purpose of improving toughness and color tone, (meth) acrylate monomers are preferably used. Examples of the vinyl cyanide-based monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, and acrylonitrile is particularly preferable.
(Meth) acrylic ester monomers include acrylic acid and methacrylic acid methyl, ethyl, propyl, n
Examples thereof include an esterified product with -butyl and i-butyl, and methyl methacrylate is particularly preferable.

Other vinyl monomers which can be copolymerized with these, if necessary, include maleimide monomers such as maleimide, N-methylmaleimide and N-phenylmaleimide, acrylic acid, methacrylic acid and maleic acid. Carboxyl group-containing vinyl monomers such as acid, maleic anhydride, phthalic acid and itaconic acid; amino group-containing vinyl monomers such as acrylamide and methacrylamide; acrylic acid 2
-A hydroxyl group-containing vinyl monomer such as -hydroxyethyl and 2-hydroxyethyl methacrylate, and an epoxy group-containing vinyl monomer such as glycidyl acrylate and glycidyl methacrylate can also be used.

(A2) The ratio of the aromatic vinyl monomer which is a constituent component of the vinyl (co) polymer is 2 to the total monomer.
It is at least 0% by weight, preferably at least 50% by weight. When the proportion of the aromatic vinyl monomer is less than 20% by weight, the impact resistance of the resin composition is poor, which is not preferable. When a vinyl cyanide monomer is mixed, the content is preferably 60% by weight or less, more preferably 50% by weight or less, from the viewpoint of impact resistance and fluidity. When a (meth) acrylate monomer is mixed, the amount is preferably 80% by weight or less, more preferably 75% by weight or less from the viewpoint of toughness and impact resistance. When other vinyl monomers copolymerizable therewith are mixed, the content is preferably 60% by weight or less, more preferably 50% by weight or less.

The properties of the vinyl (co) polymer are not limited, but the intrinsic viscosity [η] (methyl ethyl ketone solvent, 30 ° C.
Measurement) is 0.40 to 0.65 dl / g, especially 0.45
０．５0.55 dl / g, N, N-dimethylformamide solvent, and 0.30 when measured at 30 ° C.
5 to 0.85 dl / g, especially 0.45 to 0.70 dl / g
Those having a range of g are preferable because a resin composition having excellent impact resistance and moldability can be obtained.

The method for producing the vinyl (co) polymer is not particularly limited, and includes a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method.
Conventional methods such as a suspension polymerization method and a solution-bulk polymerization method can be used.

The organic phosphorus compound (B) used in the present invention is a phosphoric ester represented by the following general formula (I).

[0033]

Embedded image In the formula (I), X represents an arylene group, and R ¹ , R ² , R ³ , and R ^{4 each} represent a substituted or unsubstituted phenyl group.

Examples of the arylene group include an o-phenylene group, an m-phenylene group, a p-phenylene group, a biphenylene group and a phenyleneoxyphenylene group.
Among them, an m-phenylene group and a p-phenylene group are preferably used.

R ¹ , R ² , R ³ , and R ⁴ are substituted or unsubstituted phenyl groups, provided that at least one of R ¹ , R ² , R ³ , and R ⁴ has 1 to 4 carbon atoms. Alkyl-substituted phenyl group "and" R ¹ , R ² , R ³ , and R ⁴ have 1 to 1 carbon atoms.
4 alkyl-substituted phenyl group ", and those having the structure of" R ¹ , R ² , R ³ , and R ⁴ are alkyl group di-substituted phenyl groups having 1 to ⁴ carbon atoms " The alkyl group having 1 to 3 carbon atoms is preferably used.

Specifically, resorcinol-bis (di-
2,6-dimethylphenyl phosphate), resorcinol-bis (di-3,5-dimethylphenyl phosphate), resorcinol-bis (di-2,6-diethylphenyl phosphate), resorcinol-bis (di-
3,5-diethylphenyl phosphate), resorcinol-bis (di-2,6-dipropylphenylphosphate), resorcinol bis (di-3,5-dipropylphenylphosphate), hydroquinone-bis (di-2,6 -Dimethylphenyl phosphate), hydroquinone-bis (di-3,5-dimethylphenyl phosphate), hydroquinone-bis (di-2,6-diethylphenyl phosphate), resorcinol-bis (di-
3,5-diethylphenylphosphate), hydroquinone-bis (di-2,6-dipropylphenylphosphate), hydroquinone-bis (di-3,5-dipropylphenylphosphate), 4,4'-biphenylene-
Bis (di-2,6-dimethylphenyl phosphate),
4,4'-biphenylene-bis (di-3,5-dimethylphenyl phosphate), 4,4'-biphenylene-bis (di-2,6-diethylphenyl phosphate),
4,4'-biphenylene-bis (di-3,5-diethylphenyl phosphate), 4,4'-biphenylene-bis (di-2,6-dipropylphenyl phosphate),
4,4'-biphenylin-bis (di-3,5-dipropylphenylphosphate), resorcinol-bis (di-2-methylphenylphosphate), resorcinol-bis (di-3-methylphenylphosphate), resorcinol-bis (Di-4-methylphenyl phosphate), resorcinol-bis (di-5-methylphenyl phosphate), resorcinol-bis (di-6-methylphenyl phosphate), hydroquinone-bis (di-2-methylphenyl phosphate), Hydroquinone-bis (di-3-methylphenyl phosphate),
Hydroquinone-bis (di-4-methylphenyl phosphate), hydroquinone-bis (di-5-methylphenyl phosphate), hydroquinone-bis (di-6
Methylphenyl phosphate), 4,4′-biphenylene-bis (di-2-methylphenyl phosphate),
4,4'-biphenylene-bis (di-3-methylphenyl phosphate), 4,4'-biphenylene-bis (di-4-methylphenyl phosphate), 4,4'-biphenylene-bis (di-5-methyl) Phenyl phosphate), 4,4'-biphenylene-bis (di-5-methylphenyl phosphate), resorcinol-bis (diphenyl phosphate), hydroquinone-bis (diphenyl phosphate), 4,4'-biphenylene-bis (diphenyl phosphate) And resorcinol-bis (di-2,6-dimethylphenyl phosphate), hydroquinone-bis (di-2,6-dimethylphenyl phosphate), and 4,4′-biphenylene-bis (di-2,6). -Dimethylphenyl phosphate), resorcinol-bis ( 4-methyl-phenyl phosphate), hydroquinone - bis (di-4-methylphenyl phosphate), resorcinol - bis (diphenyl phosphate) is rigid, molded article surface gloss, preferably excellent in flame retardancy.

(B) The method for producing the organic phosphorus compound is not particularly limited. For example, after reacting phosphorus oxychloride and hydroquinone in a solvent at a substantially 2: 1 molar ratio, 2,6-
Hydroquinone-bis (2,6-dimethylphenyl) phosphate can be obtained by adding an appropriate amount of dimethylphenol and reacting.

The (C) ammonium polyphosphate used in the present invention is a compound represented by the general formula (II), and may be a branched compound or a compound whose terminal is partially substituted by another group. it can. More preferably, the compound has a phosphorus content of about 25 to 32% by weight. For example, "Hostaflam AP42" manufactured by Hoechst Japan KK
2 "or" Sumisafe P "manufactured by Sumitomo Chemical Co., Ltd. can be used.

[0039]

Embedded image In the general formula (II), n represents the degree of polymerization of ammonium polyphosphate, and its value is usually 1 to 5,000, preferably 3
2,000, particularly preferably 5-1,000.

The present invention also relates to a modified ammonium polyphosphate obtained by subjecting the above-mentioned ammonium polyphosphate to a surface treatment with a triazine derivative such as a melamine or benzoguanamine compound, for example, “Hostaf manufactured by Hoechst Japan KK”
lam AP462 "or a modified ammonium polyphosphate chemically bonded to a polymer, for example," Te
rraju C60 "and the like can also be included. The average particle size of ammonium polyphosphate is not particularly limited, but is 50 μm or less, particularly 20 μm.
The following are preferable because they exhibit high flame retardancy.

Red phosphorus, which is another inorganic phosphorus compound (C) used in the present invention, includes, in addition to very common red phosphorus, red phosphorus such as magnesium hydroxide, aluminum hydroxide,
Surface-coated with metal hydroxide such as zinc hydroxide and titanium hydroxide, metal hydroxide such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide and titanium hydroxide, and thermosetting resins such as phenolic resin Surface-coated with magnesium hydroxide, aluminum hydroxide,
Examples include multi-layer surface-coated products which are surface-coated with a metal hydroxide such as zinc hydroxide or titanium hydroxide and then surface-coated with a thermosetting resin such as a phenol resin. In particular, those that have been surface-coated with a metal hydroxide or a thermosetting resin have handling properties, and physical properties of the resin composition,
Excellent flame retardancy and suitable.

The particle size of red phosphorus is not particularly limited, but an average particle size of 30 μm or less, preferably 20 μm or less is excellent in physical properties and flame retardancy and can be suitably used.

In order to exhibit the effect of the present invention, the ratio of the organic phosphorus compound (B) to the inorganic phosphorus compound (C) is 95: 5 to 5
0:50 is required, preferably 85: 15-60:
40 (weight ratio). If the ratio of the component (B) and the component (C) is out of the range, the flame extinction due to the drip property deteriorates in a combustion test based on the UL94 standard, which is not preferable.

The present invention further requires that the total phosphorus atom content of component (B) and component (C) be 1.2 to 8.0 parts by weight based on 100 parts by weight of component (A). , Preferably 1.5 to 6.0 parts by weight. If the phosphorus atom content is out of the range, the flame retardancy of the resin composition or the falling weight impact of a thin-walled molded product deteriorates, which is not preferable.

In the present invention, a higher fatty acid amide may be added for the purpose of further increasing the drip property and the falling weight impact of the thin molded article.

Examples of higher fatty acid amides include stearic acid monoamide, stearic acid bisamide, lauric acid bisamide, lauric acid ethylene bisamide, stearic acid ethylene bisamide, hydroxystearic acid bisamide, hydroxystearic acid ethylene bisamide, and particularly stearic acid. Ethylene bisamide, hydroxystearic acid ethylene bisamide, and lauric acid ethylene bisamide have excellent flame retardancy and impact resistance, and can be suitably used.

The method for producing the resin composition of the present invention is not particularly limited. For example, (A) a rubber-reinforced styrene resin, (B) an organic phosphorus compound, (C) ammonium polyphosphate, and / or red phosphorus are mixed. It is then commercialized by melt-kneading with a Banbury mixer, roll, extruder, kneader or the like.

The thermoplastic resin of the present invention can be blended with this and another thermoplastic resin. For example, polyphenylene ether, polycarbonate, polyglutarimide,
The impact resistance and heat resistance can be improved by mixing polycyclohexane dimethylene terephthalate and the like, and the chemical resistance can be improved by mixing polyolefin, polybutylene terephthalate, polyethylene terephthalate and polyamide. Furthermore, if necessary, fillers such as glass fiber, talc, and potassium whisker, antioxidants such as phenylisodecyl phosphate, various stabilizers such as ultraviolet absorbers, lubricants such as pigments and dyes, and plasticizers are required. It can be added in an amount.

The thermoplastic resin composition of the present invention is melt molded and used as a resin molded product. This resin molded product has excellent drip properties at a molded product thickness of 0.5 to 3 mm, especially 2 mm or less, exhibits V-2 flame retardancy according to UL94 standard, and has excellent falling weight impact of a thin molded product. Printers, personal computers, displays, CRT displays, faxes,
It is useful for members of DVD drives, PD drives, floppy disk drives, storage devices such as DVD drives, PD drives, and floppy disk drives, as well as copy, word processors, and notebook computers.

[0050]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples. In the examples, the number of parts and% indicate parts by weight and% by weight, respectively, and the unit "" means inches (1 inch = 2.54 cm).

Reference Example 1 (A) Preparation of Rubber Reinforced Styrenic Resin A method for preparing a rubber reinforced styrene resin is described below. The graft ratio was determined by the following method. Acetone was added to a predetermined amount (m) of the graft copolymer and refluxed for 4 hours. This solution is cooled to 8000 rpm (480 × 10 ³ s ⁻¹ ).
(Acceleration 10,000G (about 100 × 10 ³ m / s ² ))
After centrifugation for 30 minutes, insoluble matter was filtered. This insoluble content is 7
It dried under reduced pressure at 0 degreeC for 5 hours, and measured the weight (n).

Graft ratio = [(n)-(m) × L] /
[(M) × L] × 100 Here, L means the rubber content of the graft copolymer.

<A1-1> A monomer mixture 40 composed of 70% styrene and 30% acrylonitrile in the presence of 60 parts (in terms of solid content) of 60 parts of polybutadiene latex (average rubber particle diameter 0.3 μm, gel content 85%) And then emulsion polymerization was carried out. The obtained graft copolymer is coagulated with sulfuric acid,
The mixture was neutralized with caustic soda, washed, filtered and dried to prepare a powdery graft copolymer <A1-1>. The obtained graft copolymer had a graft ratio of 35%. This graft copolymer contained 18.2% of a non-graft copolymer composed of 70% of styrene structural units and 30% of acrylonitrile. The intrinsic viscosity of the soluble portion of methyl ethyl ketone was 0.31 dl / g.

<A1-2> 35 parts (in terms of solids) of polybutadiene (average rubber particle diameter 0.23 μm, gel content 80%), styrene-butadiene copolymer rubber copolymerized with 25% styrene (average rubber particles) Styrene 7 in the presence of 10 parts (in terms of solids)
Monomer mixture 5 consisting of 4% and 26% acrylonitrile
Emulsion polymerization was conducted by adding 5 parts. The obtained graft copolymer was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to prepare a powdery graft copolymer <A1-2>. The obtained graft copolymer has a graft ratio of 39%.
Met. This graft copolymer contained 37% of a non-graft copolymer composed of 74% of styrene structural units and 26% of acrylonitrile. The intrinsic viscosity of the soluble portion of methyl ethyl ketone is 0.41 dl / g.
Met.

Reference Example 2 (A2) Preparation of Vinyl Copolymer A monomer mixture consisting of 72% of styrene and 28% of acrylonitrile was subjected to suspension polymerization to prepare a vinyl copolymer.
The resulting vinyl copolymer had a limiting viscosity of 0.51 of the methyl ethyl ketone-soluble component.

Reference Example 3 (B) Organophosphorus Compound <B-1> PX200 (manufactured by Daihachi Chemical Co., Ltd.) which is resorcinol-bis (di-2,6-dimethylphenyl phosphate) was used.

<B-2> Hydroquinone-bis (di-
PX2 which is 2,6-dimethylphenyl phosphate)
01 (manufactured by Daihachi Chemical Co., Ltd.) was used.

<B-3> CR733S (manufactured by Daihachi Chemical Co., Ltd.), which is resorcinol-bis (diphenyl phosphate), was used.

<B-4> Triphenyl phosphate was used.

Reference Example 4 (D) Ammonium Polyphosphate and Red Phosphorus <C-1> TERRAJUC60 (manufactured by Chisso Corporation) which is an ammonium polyphosphate modified with a polymer was used.

<C-2> Nova Red 280A (manufactured by Rin Kagaku Kogyo KK) having a red phosphorus content of 48% or more was used.

<C-3> Nova Red 120 (manufactured by Rin Kagaku Kogyo KK) having a red phosphorus content of 85% or more was used.

Examples 1 to 14 (A) Rubber-modified styrene resin prepared in Reference Example,
(B) An organic phosphorus compound and (C) an inorganic phosphorus compound were mixed at the compounding ratios shown in Table 1, and 2 parts of ethylene bisamide hydroxystearate was further added to 100 parts by weight of the rubber-modified styrene resin (A). 30mm with vent
A pellet-shaped polymer was produced by melt-kneading and extruding at a resin temperature of 200 ° C. with a φ2 screw extruder. Then, a test piece was molded by an injection molding machine at a cylinder temperature of 210 ° C. and a mold temperature of 60 ° C., and the physical properties were measured under the following conditions.

1/2 "Izod impact strength: ASTM
D256-56A Drop weight impact strength: 5R for disc molded product (40φ × 2mmt)
The weight having the tip is dropped, and the height at which the test piece breaks by 50% and the weight of the weight at that time are determined.

MFR: JIS K7210 (220 ° C.,
(Load: 10 kgf (about 98.07 N)) A larger value means that the fluidity during molding is better.

Flame retardancy: A vertical combustion test was performed according to UL94 standard. The thickness of the test piece is 3, 1.5, 0.5 m
m.

[0067]

[Table 1]

[Table 2] Comparative Examples 1 to 6 (A) Rubber-modified styrenic resin prepared in Reference Example,
(B) The organic phosphorus compound and (C) the inorganic phosphorus compound were mixed at the compounding ratio shown in Table 1, and the respective physical properties were measured in the same manner as in the examples. Table 2 shows the measurement results.

The following is clear from the results in Table 2.
The resin compositions of the present invention (Examples 1 to 15) are all excellent in impact resistance, fluidity, and flame retardancy, particularly in terms of thin-walled flame retardancy and falling weight impact.

On the other hand, when the ratio of (B) the organic phosphorus compound: (C) the inorganic phosphorus compound is out of the range of 95: 5 to 50:50 (weight ratio) (comparative examples 1 to 3), flame retardancy is obtained. It is not preferable because the flame retardancy of thinner wall is inferior.

Further, when an organic phosphorus compound (B) other than the general formula (I) is used (Comparative Example 4), the impact resistance is deteriorated, which is not preferable.

(A) When the phosphorus atom content exceeds 8 parts by weight based on 100 parts by weight of the rubber-reinforced styrene resin (Comparative Example 5), the impact resistance is deteriorated, which is not preferable.

(A) When the phosphorus atom content is less than 1.2 parts by weight based on 100 parts by weight of the rubber-reinforced styrene resin (Comparative Example 6), the flame retardancy becomes poor, which is not preferable.

[0073]

The thermoplastic resin composition of the present invention does not necessarily require a bromine or chlorine compound, and exhibits excellent flame retardancy, especially flame retardancy of thin-walled molded articles, falling weight impact strength and moldability. Show.

Claims (6)

[Claims] 1. An organic phosphorus compound (B) represented by the general formula (I) and at least one selected from (C) ammonium polyphosphate and red phosphorus based on 100 parts by weight of a rubber-reinforced styrene resin (A). 95: 5 to 5 with one kind of inorganic phosphorus compound
0:50 (weight ratio), and the total phosphorus atom content of the component (B) and the component (C) is 1.2 to 8.0 parts by weight based on 100 parts by weight of the component (A). A flame-retardant thermoplastic resin composition characterized by the following. Embedded image (In the formula, X is an arylene group, and R ¹ , R ² , R ³ , and R ⁴ are a substituted or unsubstituted phenyl group.) 2. The method according to claim 1, wherein (A) the rubber-reinforced styrenic resin comprises (a)
1) 95 to 20 parts by weight of a monomer or monomer mixture containing 20% by weight or more of an aromatic vinyl monomer is graft-polymerized to (b) 5 to 80 parts by weight of a rubbery polymer ( A
1) 5 to 100% by weight of a graft (co) polymer;
2) (A2) A resin composition comprising 0 to 95% by weight of a vinyl (co) polymer obtained by polymerizing a monomer or a monomer mixture containing 20% by weight or more of an aromatic vinyl type monomer. The flame-retardant thermoplastic resin composition according to claim 1, which is excellent in drip properties. 3. The thermoplastic resin composition according to claim 1, wherein the flame retardancy based on UL94 standard is V-2 when the test piece has a thickness of 0.5 to 3.0 mm.
2. The flame-retardant thermoplastic resin composition according to any one of 2. 4. The rubbery polymer giving (A1) a graft copolymer has a weight average particle size (b1) of 0.20 to 0.25 μm.
The flame-retardant thermoplastic resin composition according to any one of claims 1 to 3, wherein two types of m and (b2) are used in the range of 0.50 to 0.70 µm. 5. The rubbery polymer (A1) which gives the graft copolymer has a ratio of (b1) to (b2) of from 90:10 to 6
The flame-retardant thermoplastic resin composition according to claim 4, wherein the ratio is 0:40 (weight ratio). 6. An injection-molded article comprising the flame-retardant thermoplastic resin composition according to claim 1 and having a minimum thickness of 2 mm or less.