JP2000297208A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition having excellent flame retardance fluidity and impact resistance. SOLUTION: This composition comprises a polycarbonate (A-1) having 3,000 to 20,000 weight-average molecular weight, a flame-retardant (B) and polytetrafluoroethylene-containing mixed powder (C). Or, the composition comprises the polycarbonate (A-1) having 3,000 to 20,000 weight-average molecular weight and an aromatic vinyl polymer (A-2), the flame-retardant (B) and the polytetrafluoroethylene-containing mixed powder (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having excellent flame retardancy.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for flame retardancy of resin materials. For example, in the case of housing materials for OA equipment such as computers and printers, and home electric appliances such as televisions and audio equipment, there is a strong demand for flame retardancy to reduce fire damage. Further, as the weight and thickness of the device become thinner and the shape becomes more complicated, higher flame retardancy is required for the resin material. In addition, it is important that the resin does not drip (drip) particularly during combustion, in order to prevent the spread of fire in a fire.

[0003] As a method for improving the drip-preventing property of a thermoplastic resin, the addition of polytetrafluoroethylene is effective. However, since polytetrafluoroethylene is fibrillated in the thermoplastic resin, the flowability of the thermoplastic resin is reduced. It is well known that it involves a decrease.

As a method of improving the fluidity of a thermoplastic resin, it is effective to reduce the molecular weight of the resin itself, but it is well known that the resin is accompanied by a decrease in impact resistance and the like.

Although the addition of polytetrafluoroethylene improves the flame retardancy of a thermoplastic resin, the price of polytetrafluoroethylene is much higher than that of a thermoplastic resin. Even so, the price of the thermoplastic resin composition is greatly increased. In addition, polytetrafluoroethylene has poor compatibility with most thermoplastic resins, and thus easily forms aggregates in the resin composition. Agglomerates of polytetrafluoroethylene have problems that they impair the appearance of the molded product, increase the amount of addition required for the expression of flame retardancy, increase the price, and easily impair mechanical properties such as impact strength.

As described above, there is a strong demand for a technique for uniformly dispersing polytetrafluoroethylene in a resin and improving the flame retardancy of the thermoplastic resin at least in an added amount.

[0007] Thus, the following attempts have been made to improve the flame retardancy of a thermoplastic resin composition by adding a mixture of polytetrafluoroethylene and an organic polymer.

Japanese Unexamined Patent Publication No. 60-258263 discloses that the flame retardancy is improved by adding a powder obtained by mixing and coagulating a polytetrafluoroethylene dispersion and an aromatic vinyl polymer dispersion. It is stated to improve. JP-A-9-95
No. 583 describes that a powder obtained by polymerizing an organic monomer in the presence of a polytetrafluoroethylene dispersion is excellent in handleability. JP-A-10-310707 discloses that a thermoplastic resin composition comprising a polycarbonate, an acrylonitrile-styrene-butadiene copolymer and a polyorganosiloxane-containing composite rubber-based graft copolymer has excellent flame retardancy and impact resistance. It is described.

[0009] However, these methods have a drawback that the flowability is further reduced in order to promote the fibrillation of polytetrafluoroethylene.

As described above, a method for obtaining a thermoplastic resin composition having excellent flame retardancy, fluidity and impact resistance by suppressing the amount of polytetrafluoroethylene to be added has not yet been found. Was.

[0011]

An object of the present invention is to provide a thermoplastic resin composition having excellent flame retardancy, fluidity and impact resistance.

[0012]

The inventors of the present invention have conducted intensive studies and have found that by adding a mixture of polytetrafluoroethylene and an organic polymer to a polycarbonate resin having a low molecular weight, flame retardancy, fluidity, and the like can be improved. The present inventors have found that a thermoplastic resin composition having excellent impact resistance can be obtained, and have reached the present invention.

The gist of the present invention is that the weight average molecular weight is 300
A thermoplastic resin composition comprising a polycarbonate (A-1) having a molecular weight of 0 to 20,000, a flame retardant (B) and a mixed powder containing polytetrafluoroethylene (C); and a polycarbonate having a weight average molecular weight of 3000 to 20,000 ( A-
1) A thermoplastic resin composition comprising an aromatic vinyl polymer (A-2), a flame retardant (B) and a mixed powder containing polytetrafluoroethylene (C).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarbonate (A-1) according to the present invention has the general formula

Embedded image And a bifunctional phenol (HO-Ar-OH)
Are linked by a carbonate bond.

Examples of difunctional phenols include hydroquinone, 4,4'-dihydroxydiphenyl, 1,1
-Bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [abbreviated as bisphenol A], 1,1-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) Examples thereof include sulfone and 4,4′-dihydroxydiphenyl ether, and one or more of these can be used.

The weight average molecular weight of the polycarbonate is from 3,000 to 20,000, preferably from 10,000 to 20,000. When the molecular weight is high, the fluidity of the obtained thermoplastic resin composition decreases, and when the molecular weight is low, the impact resistance decreases.

Considering the mechanical properties and cost of the thermoplastic resin obtained, bisphenol A is preferred.

The aromatic vinyl polymer (A-
2) is a polymer obtained by polymerizing a monomer containing an aromatic vinyl monomer as a component. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, and p-methylstyrene. Examples of the aromatic vinyl polymer, aromatic vinyl homopolymer,
Butadiene rubber, styrene-butadiene copolymer, ethylene-propylene copolymer, aromatic vinyl polymer containing various rubbery polymers such as ethylene-propylene-diene copolymer, styrene-maleic anhydride copolymer, Examples thereof include a styrene-methyl methacrylate copolymer, a styrene-acrylonitrile copolymer, a styrene-acrylonitrile-butadiene copolymer, and a styrene-acrylonitrile-acrylate copolymer.

The polycarbonate (A-1) or the polycarbonate (A-1) and the aromatic vinyl polymer (A-2) of the present invention include polyphenylene ether, polyolefin, polyester, polyamide, polyvinyl chloride, PMMA, and various elastomers. And other thermoplastic resins such as polyoxymethylene can be used in an amount of 50% by weight or less of the whole.

The flame retardant (B) according to the present invention is a conventionally known flame retardant or a flame retardant auxiliary agent which is used in combination with a flame retardant to promote a flame retarding action. Examples include phosphorus-containing compounds, halogen-containing compounds, metal oxides, metal hydroxides, triazine compounds, red phosphorus, zirconium compounds, polyphosphate compounds, sulfamic acid compounds, and the like.

Examples of the phosphorus-containing compound include red phosphorus and a phosphoric ester compound. Phosphoric acid ester compounds have the general formula

Embedded image (However, R1, R2, R3, and R4 are a hydrogen atom or an organic group, except when R1 = R2 = R3 = R4 = H. X is a divalent or higher valent organic group. P is 0 or 1.) Q is an integer of 1 to 30. r is an integer of 0 or more.)

Examples of the organic group include an alkyl group, a cycloalkyl group and an aryl group, and various substituents can be introduced. Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, a halogen,
Examples include an aryl group, an aryloxy group, an arylthio group, and a halogenated aryl group. One or more of these can be used, and an example of such an organic group is an arylalkoxyalkyl group. These substituents can be bonded via an oxygen atom, a sulfur atom, a nitrogen atom and the like, and an example of such an organic group is an arylsulfonylaryl group.

The divalent or higher valent organic group is defined as
A group formed by removing one or more hydrogen atoms bonded to a carbon atom, and examples thereof include an alkylene group, a phenylene group, and a derivative of a polynuclear phenol such as bisphenol. The relative positions of two or more free valences are not particularly limited. Examples of the divalent or higher valent organic group include hydroquinone, resorcinol, diphenylolmethane, diphenyloldimethylmethane, dihydroxydiphenyl, p, p'-dihydroxydiphenylsulfone, and dihydroxynaphthalene.

Examples of such phosphate ester compounds include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate. ,
Diisopropylphenyl phosphate, tris (chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (chloropropyl) phosphate,
Bis (2,3-dibromopropyl) -2,3-dichloropropyl phosphate, tris (2,3-dibromopropyl) phosphate, bis (chloropropyl) monooctyl phosphate, bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate And polyphosphates such as trioxybenzene triphosphate. Red phosphorus, triphenyl phosphate, and various polyphosphates are preferable in consideration of the flame retardancy of the obtained thermoplastic resin composition.

Examples of the halogen-containing compound include tetrabromobisphenol A, decabromodiphenyl oxide, hexabromocyclododecane, octabromodiphenyl ether, bistribromophenoxyethane, ethylenebistetrabromophytylimide, tribromophenol, and halogenated bisphenol. Examples include various halogenated epoxy oligomers obtained by the reaction of A with epihalohydrin, carbonate oligomers containing halogenated bisphenol A as a constituent, halogenated polystyrene, chlorinated polyolefin, polyvinyl chloride, and the like.

Examples of metal oxides include antimony oxide such as antimony pentoxide and antimony trioxide.

Examples of the triazine compound include melamine, ethylene dimelamine, triguanamine, benzoguanamine, succinoguanamine, adiboguanamine, methylglutalogamine, melam, melon, melamine phosphate,
Melamine resin, BT resin, melamine cyanurate, ethylene dimelamine cyanurate, triguanamine cyanurate, succinoguanamine cyanurate, benzoguanamine cyanurate and the like can be mentioned.

One or more flame retardants (B) according to the present invention can be used.

The polytetrafluoroethylene-containing mixed powder (C) according to the present invention comprises polytetrafluoroethylene particles having a particle diameter of 10 μm or less and an organic polymer, and polytetrafluoroethylene has a particle diameter of 10 μm.
It is necessary that it does not form an aggregate. Furthermore, from the viewpoint of dispersibility when blended into a thermoplastic resin, the content of the polytetrafluoroethylene component needs to be 1 to 30% by weight, and the content of the organic polymer component needs to be 70 to 99% by weight. If the content of the polytetrafluoroethylene component is less than 1% by weight, the effect of improving the flame retardancy becomes insufficient, and if it exceeds 30% by weight, the surface appearance may be adversely affected.

The polytetrafluoroethylene-containing mixed powder (C) is prepared by mixing an aqueous dispersion of polytetrafluoroethylene particles having a particle diameter of 0.05 to 1.0 μm and an aqueous dispersion of organic polymer particles. To solidify or powder by spray drying, or 0.05 to 1.0 particle size
After polymerizing the monomers constituting the organic polymer in the presence of an aqueous dispersion of polytetrafluoroethylene particles having a particle diameter of 0.05 μm, the mixture is powdered by coagulation or spray drying, or a polymer having a particle diameter of 0.05 to 1.0 μm. In a dispersion obtained by mixing an aqueous dispersion of tetrafluoroethylene particles and an aqueous dispersion of organic polymer particles, it can be obtained by emulsion polymerization of a vinyl monomer, followed by coagulation or pulverization by spray drying. .

[0031] The polytetrafluoroethylene-containing mixed powder (C) according to the present invention is used to obtain a mixed powder (C) having a particle size of 0.1.
The aqueous dispersion of polytetrafluoroethylene particles having a particle size of from 0.5 to 1.0 μm is obtained by polymerizing a tetrafluoroethylene monomer by emulsion polymerization using a fluorinated surfactant.

In the emulsion polymerization of polytetrafluoroethylene particles, copolymer components such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, and perfluoroalkylvinyl ether are contained as long as the properties of polytetrafluoroethylene are not impaired. Fluorinated olefins and fluorinated alkyl (meth) acrylates such as perfluoroalkyl (meth) acrylate can be used. The content of the copolymer component is preferably 10% by weight or less based on tetrafluoroethylene.

Commercially available raw materials for the polytetrafluoroethylene particle dispersion include Fluon AD-1, AD-936 manufactured by Asahi Glass Fluoropolymer Co., Ltd., and Polyflon D-1, D-2 manufactured by Daikin Industries, Ltd .; Teflon 30J manufactured by the company can be cited as a representative example.

The organic polymer constituting the polytetrafluoroethylene-containing mixed powder used in the present invention is not particularly limited, but from the viewpoint of dispersibility, (A-1)
Or it is preferable that it has high affinity with (A-2).

Specific examples of the monomer for forming the organic polymer include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene, o-ethylstyrene, p-methylstyrene and p-methylstyrene. Aromatic vinyl monomers such as chlorostyrene, o-chlorostyrene, 2,4-dichlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene; methyl acrylate,
Methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate,
Octadecyl acrylate, octadecyl methacrylate,
(Meth) acrylate monomers such as cyclohexyl acrylate and cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as maleic anhydride;
-Maleimide monomers such as -phenylmaleimide, N-methylmaleimide, N-cyclohexylmaleimide; epoxy group-containing monomers such as glycidyl methacrylate; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl acetate; Vinyl carboxylate monomers such as vinyl butyrate; olefin monomers such as ethylene, propylene and isobutylene; and diene monomers such as butadiene, isoprene and dimethylbutadiene.
These monomers can be used alone or in combination of two or more.

Among these monomers, preferred from the viewpoint of affinity with (A-1) or (A-2) are:
Monomers containing at least 30% by weight of one or more monomers selected from the group consisting of aromatic vinyl monomers and vinyl cyanide monomers can be mentioned. Particularly preferred are monomers containing at least 30% by weight of one or more monomers selected from the group consisting of styrene and acrylonitrile.

The polytetrafluoroethylene-containing mixed powder (C) used in the present invention was subjected to salting-out and coagulation by throwing the aqueous dispersion into hot water in which metal salts such as calcium chloride and magnesium sulfate were dissolved. It can be dried later or powdered by spray drying.

[0038] Ordinary polytetrafluoroethylene fine powder becomes an aggregate of 100 µm or more in the step of recovering as a powder from the state of a particle dispersion, and thus it is difficult to uniformly disperse it in a thermoplastic resin. On the other hand, the polytetrafluoroethylene-containing mixed powder used in the present invention has extremely dispersibility in the thermoplastic resin (A) because polytetrafluoroethylene alone does not form a domain having a particle diameter of more than 10 μm. Are better. As a result, in the thermoplastic resin composition of the present invention, polytetrafluoroethylene is efficiently made into fine fibers in the thermoplastic resin, and has excellent flame retardancy and excellent surface properties.

The thermoplastic resin composition according to the present invention comprises (A)
-1) or (A-1) + (A-2), flame retardant (B)
And polytetrafluoroethylene-containing mixed powder (C)
Can be obtained by mixing.

The mixing ratio is not particularly limited, but is preferably (A-1) or (A-1) + in consideration of the flame retardancy, mechanical properties and cost of the thermoplastic resin composition obtained.
(A-2) For 100 parts by weight, (B) 0.1 to 70 parts by weight.
Parts by weight, (C) 0.001 to 50 parts by weight, more preferably (B) 2 to 30 parts by weight, (C) 0.01 to 10 parts by weight.
Parts by weight.

Further, by increasing the ratio of the polytetrafluoroethylene-containing mixed powder (C), a master batch mixed with (A-1) or (A-1) + (A-2) is prepared in advance. Then, the masterbatch, (A-1) or (A-1) + (A-2), and the flame retardant (B) can be mixed in a desired composition.

The method of mixing is not particularly limited, but may be a generally known method using a single screw extruder, a twin screw extruder, a batch kneader, a roll, or the like.

The thermoplastic resin composition according to the present invention may contain various additives such as fillers such as glass fiber, talc and mica, dyes, pigments, stabilizers and reinforcing agents.

The thermoplastic resin composition according to the present invention comprises OA
It can be used in fields where flame retardancy is required, such as housing materials for devices and home appliances.

Hereinafter, the present invention will be described with reference to examples. In Reference Examples, Examples and Comparative Examples, "parts" and "%" are "parts by weight" and "% by weight" unless otherwise specified.
Means

[0046]

EXAMPLES Various physical properties in Examples and Comparative Examples were measured by the following methods.

(1) Solids: The particle dispersion was heated at 170 ° C. for 3 hours.
It was obtained by drying for 0 minutes.

(2) Particle size distribution, weight average particle size: A particle dispersion diluted with water was used as a sample solution, and a dynamic light scattering method (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature: 25 ° C., scattering angle: 90) Degree).

(3) Zeta potential: 0.0
An electrophoresis method (ELS800, manufactured by Otsuka Electronics Co., Ltd.)
At a temperature of 25 ° C. and a scattering angle of 10 °).

(4) Combustion test: A combustion test was performed with a test piece thickness of 0.8 mm in accordance with the UL94-V standard set by Underwriters Laboratories Corporation to make a judgment. A test piece was obtained by injection molding the obtained resin composition.

(5) Melt flow rate (MFR) A temperature of 250 ° C. and a load of 5 k according to ASTM D1238.
g.

(6) Izod Impact Strength (Izd) A temperature of 23 ° C. and a humidity of 50% R according to ASTM D256.
H, notched, measured at 3.2 mm test specimen thickness.

A test piece was obtained by injection-molding the obtained resin composition.

Reference Example 1 Production of polytetrafluoroethylene-containing mixed powder (C-1) 300 parts of distilled water and 2 parts of sodium dodecylbenzenesulfonate were placed in a flask equipped with a stirrer, a cooler, a thermocouple, a nitrogen inlet, and a reagent dropping device. It was charged and heated to 70 ° C. in a water bath under a nitrogen stream. After dissolving 0.0004 parts of ferrous sulfate, 0.0012 parts of disodium ethylenediaminetetraacetate, and 0.8 parts of sodium formaldehyde sulfoxylate in 5 parts of distilled water and adding to the contents, 30 parts of acrylonitrile and 70 parts of styrene were added. , A mixture of 0.5 parts of cumenehydroxyperoxide was added dropwise over 3 hours, and then the mixture was heated and stirred for 1 hour to obtain an acrylonitrile-styrene copolymer particle dispersion (P-1). The solid content of P-1 is 25.1%, the weight average particle diameter is 100 μm, and the surface potential is -3.
It was 0 mV.

As a polytetrafluoroethylene particle dispersion, Fluon AD936 manufactured by Asahi Glass Fluoropolymers Co., Ltd.
Was used. AD936 contains 5 parts of polyoxyethylene alkylphenyl ether per 100 parts of polytetrafluoroethylene, has a solid content of 63.0%, shows a single particle size distribution, a weight average particle size of 290 nm, and has a surface potential − 20 mV. To 833 parts of AD936, 1167 parts of distilled water was added to obtain a polytetrafluoroethylene particle dispersion (F-1) having a solid content of 26.2%.

239.0 parts of P-1 (acrylonitrile-styrene copolymer 60 parts) and 80 parts of F-1 (polytetrafluoroethylene 20 parts) were mixed with a stirrer, a condenser,
The flask was equipped with a thermocouple, a nitrogen inlet, and a reagent dropping device, and stirred at room temperature for 1 hour under a nitrogen stream. Thereafter, the mixture was heated to 80 ° C. in a water bath and stirred for 1 hour. Ferrous sulfate 0.00
04 parts, disodium ethylenediaminetetraacetate 0.00
12 parts and 0.8 parts of sodium formaldehyde sulfoxylate are dissolved in 5 parts of distilled water and added to the contents.
A mixture of 6 parts of acrylonitrile, 14 parts of styrene, and 0.1 part of cumene hydroxy peroxide was added dropwise over 30 minutes, and the mixture was heated and stirred for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion was 28.6%, and the weight average particle size was 220 nm.

The particle dispersion was poured into an aqueous calcium chloride solution, the solid was separated, filtered and dried to obtain a polytetrafluoroethylene-containing mixed powder (C-1). The dried C-1 was molded using a press molding machine, an ultrathin section was collected from the molded product using a microtome, and observed with a transmission electron microscope without staining. Polytetrafluoroethylene was observed as a dark part, and no aggregate exceeding 10 μm was observed.

Reference Example 2 Production of polytetrafluoroethylene-containing mixed powder (C-2) 298.8 parts of acrylonitrile-styrene copolymer particle dispersion (P-1) used in Reference Example 1 (75 parts of acrylonitrile-styrene copolymer) And 100 parts of the polytetrafluoroethylene particle dispersion (F-1) used in Reference Example 1 (25 parts of polytetrafluoroethylene) were charged into a flask equipped with a stirrer, a cooler, and a thermocouple, and placed under a nitrogen stream. The mixture was stirred at room temperature for 1 hour, and then heated to 70 ° C. in a water bath and stirred for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion was 24.9%, and the weight average particle size was 220 nm.

The particle dispersion was poured into an aqueous calcium chloride solution, the solid was separated, filtered and dried to obtain a polytetrafluoroethylene-containing mixed powder (C-2). When observation with a transmission electron microscope was performed in the same manner as in Reference Example 1, 10
No polytetrafluoroethylene aggregates larger than μm were observed.

Reference Example 3 Production of polytetrafluoroethylene-containing mixed powder (C-3) 160 parts of polytetrafluoroethylene particle dispersion (F-1) used in Reference Example 1 (polytetrafluoroethylene 4
0 parts), 1.0 part of dodecylbenzenesulfonic acid, and 70 parts of distilled water were charged into a flask equipped with a stirrer, a condenser, a thermocouple, a nitrogen inlet, and a reagent dropping device, and heated to 70 ° C. in a water bath under a nitrogen stream. Heated. After dissolving 0.0004 parts of ferrous sulfate, 0.0012 parts of disodium ethylenediaminetetraacetate, and 0.8 parts of sodium formaldehyde sulfoxylate in 5 parts of distilled water and adding to the contents, 18 parts of acrylonitrile and 42 parts of styrene were added. And a mixed solution of 0.3 parts of cumene hydroxyperoxide was added dropwise over 90 minutes, and then the mixture was heated and stirred for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion is 33.2%,
The weight average particle size was 220 nm.

The particle dispersion was poured into an aqueous calcium chloride solution, the solid was separated, filtered and dried to obtain a polytetrafluoroethylene-containing mixed powder (C-3). When observation with a transmission electron microscope was performed in the same manner as in Reference Example 1, 10
No polytetrafluoroethylene aggregates larger than μm were observed.

Examples 1 to 3 and Comparative Examples 1 to 4 The thermoplastic resins and flame retardants shown in Table 1 and C-1 to C-3 obtained in Reference Examples 1 to 3 were mixed with a twin screw extruder (WERNER & PFLEI).
Barrel temperature of 240 using DESKER ZSK30)
The mixture was melt-kneaded at ℃. The obtained pellets were formed into UL94-V test pieces at a cylinder temperature of 240 ° C. using an injection molding machine (IS-100 manufactured by Toshiba Machine Co., Ltd.). Various tests were performed using the obtained test pieces.

[0063]

[Table 1] The following is clear from the examples and the comparative examples.

(1) As in Examples 1 to 3, the thermoplastic resin composition obtained by the present invention is excellent in flame retardancy, fluidity and impact resistance.

(2) As in Comparative Examples 1 to 3, when the mixed powder containing polytetrafluoroethylene is not used, the obtained thermoplastic resin composition is inferior in flame retardancy and impact resistance.

(3) As in Comparative Examples 4 to 6, when a polycarbonate having a high molecular weight is used, the obtained thermoplastic resin composition is inferior in fluidity.

[0067]

According to the present invention, it is possible to obtain a thermoplastic resin composition having excellent flame retardancy, fluidity and impact resistance.

The present invention makes it possible to apply the thermoplastic resin composition to fields such as housing materials for large home appliances, OA equipment, etc., and its industrial utility value is enormous.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 27/18 C08L 27/18 F term (reference) 4J002 BB243 BC041 BC051 BC061 BC071 BC081 BC091 BC113 BD043 BD152 BH011 BN061 BN141 CC183 CD123 CG011 CG021 CG033 DA056 DE126 EJ056 EU026 EU186 EU196 EW046 EW056 FB262 FD010 FD133 FD136 GQ00

Claims (2)

[Claims] 1. A thermoplastic resin composition comprising a polycarbonate (A-1) having a weight average molecular weight of 3,000 to 20,000, a flame retardant (B) and a mixed powder containing polytetrafluoroethylene (C). 2. A polycarbonate (A-1) having a weight average molecular weight of 3,000 to 20,000, an aromatic vinyl polymer (A
-2), a thermoplastic resin composition comprising a flame retardant (B) and a mixed powder containing polytetrafluoroethylene (C).