JP2000034397A - Flame retardant thermoplastic resin composition - Google Patents

Abstract

(57) [Abstract] [Problem] Highly flame-retardant without using chlorine or bromine-based compound, higher heat resistance than conventionally known composition, impact resistance, solvent resistance, molding processing A thermoplastic resin composition having excellent properties and heat stability is obtained. A resin composition comprising (A) a polycarbonate resin and (B) a thermoplastic polyester resin and having a weight ratio (A) / (B) of 100/0 to 50/50 in 100 parts by weight of a resin composition. On the other hand, (C) the melting point is 60 ° C. or more,
0.1 to 30 parts by weight of a phosphate ester flame retardant having a number average molecular weight of 400 or more, and 0.1 to 50 parts by weight of anhydrous zinc borate having an amount of (D) less than 10% by weight of crystallization water (E1) at least one compound selected from the following (E1) to (E3): (E1) 0.1 to 50 parts by weight of silicone (E2) 0.1 to 100 parts by weight of silicate compound
(E3) 0.005 to 5 parts by weight of a fluorine-based resin and (F) 0.1 to 20 parts by weight of at least one resin selected from a rubbery polymer and an olefin-based resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition flame-retarded with a compound other than chlorine or bromine, and more particularly to a thermoplastic resin composition having higher heat resistance and impact resistance than conventionally known compositions. The present invention relates to a flame-retardant thermoplastic resin composition having excellent solvent resistance, moldability, heat stability, and flame retardancy.

[0002]

2. Description of the Related Art Polycarbonate resin / thermoplastic polyester resin alloy is widely used for electric and electronic parts as a resin having excellent chemical resistance, moldability and heat resistance. In recent years, especially in the use of electric and electronic parts, in order to ensure safety against fire, the resin to be used is advanced to a level that conforms to UL-94 V-0 or 5VA (US Underwriters Laboratory Standard). In many cases, flame retardancy is required, and it is necessary to make the composition flame-retardant in order to meet these requirements. On the other hand, with increasing interest in environmental issues mainly in Europe, there is a demand for a composition which can exhibit such high flame retardancy without using chlorine or bromine. As a technique for imparting such high flame retardancy to polycarbonate-based resin / thermoplastic polyester-based resin alloy without containing chlorine or bromine, various uses of phosphorus-based flame retardants have been studied. I have. For example, Japanese Patent Application Laid-Open No. Sho 64-70555 discloses a technique of adding a graft copolymer, a monophosphate flame retardant, and a fluorinated polyolefin to a resin composition comprising a polycarbonate resin and a polyalkylene terephthalate resin. Japanese Patent Application Laid-Open Publication No. H11-163,055 discloses techniques for adding a graft copolymer, an oligomeric phosphate-based flame retardant, and a fluorinated polyolefin to a resin composition comprising a polycarbonate resin and a polyalkylene terephthalate resin. However, when a phosphate ester-based flame retardant is added to the polycarbonate-based resin / thermoplastic polyester-based resin alloy as described above, any of the heat resistance, impact resistance, solvent resistance, and wet heat resistance inherent to the alloy will be obtained. Is also greatly reduced. In particular, the heat resistance may be reduced by 30 ° C. or more as compared with a non-flame retardant composition or a flame retardant composition using a halogen-based flame retardant. Was restricted. Further, Japanese Patent Application Laid-Open No. 5-179123 discloses a technique of adding a phosphate ester-based flame retardant and zinc borate to an alloy composed of a polycarbonate-based resin and a non-polycarbonate-based resin to make it flame-retardant. I have. However, since zinc borate, which is generally used, contains water of crystallization, it releases water during the molding process of the obtained resin composition, which promotes the decomposition of polycarbonate-based resins and polyester-based resins. was there. In addition, if it is a commonly used low melting point or low molecular weight phosphate ester-based flame retardant, it is avoided that either the heat resistance or the impact strength of the resin composition is significantly reduced even when added in combination with zinc borate. I couldn't.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly flame-retardant and highly free flame-retardant hardly lowering the excellent heat resistance inherent in a polycarbonate resin / thermoplastic polyester resin alloy. An object of the present invention is to obtain a composition capable of toning to a desired color and to obtain a resin composition excellent in impact resistance, thermal stability, solvent resistance, wet heat resistance, moldability and the like.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a resin composition comprising a polycarbonate resin and a thermoplastic polyester resin has a phosphate ester resin having a specific melting point and a specific molecular weight. By adding a flame retardant, zinc borate anhydride and a specific compound, it is possible to exhibit high flame retardancy without adding bromine or chlorine compounds while maintaining excellent heat resistance And also found that the impact strength, mechanical strength, moldability, chemical resistance, etc. were good, and the present invention was achieved. That is, the present invention comprises (A) a polycarbonate-based resin and (B) a thermoplastic polyester-based resin, and the weight ratio of both (A) /
Resin composition 10 in which (B) is 100/0 to 50/50
(C) a phosphate ester-based flame retardant having a melting point of 60 ° C. or more and a number average molecular weight of 400 or more based on 0 parts by weight
0.1-30 parts by weight, the amount of water of crystallization contained (D) is 10
0.1 to 50 parts by weight of zinc borate anhydride which is less than 0.1% by weight, (E1) 0.1 to 50 parts by weight of silicone (E2) 0.1 to 100 parts by weight of silicate compound (E3) fluorinated resin. 005 to 5 parts by weight of at least one compound selected from the group consisting of a compound (E) selected from the group consisting of a rubbery polymer and an olefin resin, and 0.1 to 20 parts by weight of a resin selected from the group consisting of olefin resins. It contains a flame-retardant thermoplastic resin composition.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarbonate resin (A) used in the present invention is specifically obtained by reacting a phenol compound having a valency of 2 or more with a carbonic acid diester such as phosgene or diphenyl carbonate. Things.
There are various dihydric phenols.
2,2-bis (4-hydroxyphenyl) propane [commonly known as bisphenol A] is preferred. As the dihydric phenol other than bisphenol A, for example, bis (4-
Bis (4-hydroxyphenyl) phenylmethane; bis (4-hydroxyphenyl) naphthylmethane; bis (4-hydroxyphenyl) methane
-(4-isopropylphenyl) methane; bis (3,5
-Dimethyl-4-hydroxyphenyl) methane; 1,1
-Bis (4-hydroxyphenyl) ethane; 1-naphthyl-1,1-bis (4-hydroxyphenyl) ethane;
1-phenyl-1,1-bis (4-hydroxyphenyl) ethane; 1,2-bis (4-hydroxyphenyl)
Ethane; 2-methyl-1,1-bis (4-hydroxyphenyl) propane; 2,2-bis (3,5-dimethyl-
4-hydroxyphenyl) propane; 1-ethyl-1,
1-bis (4-hydroxyphenyl) propane; 2,2
-Bis (3-methyl-4-hydroxyphenyl) propane; 1,1-bis (4-hydroxyphenyl) butane;
2,2-bis (4-hydroxyphenyl) butane; 1,
4-bis (4-hydroxyphenyl) butane; 2,2-
Bis (4-hydroxyphenyl) pentane; 4-methyl-2,2-bis (4-hydroxyphenyl) pentane;
2,2-bis (4-hydroxyphenyl) hexane;
4,4-bis (4-hydroxyphenyl) heptane;
2,2-bis (4-hydroxyphenyl) nonane; 1,
10-bis (4-hydroxyphenyl) decane; 1,1
Dihydroxydiarylalkanes such as -bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane; 1,1-bis (4-hydroxyphenyl)
Dihydroxydiarylcycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclodecane; bis (4-hydroxyphenyl) sulfone; dihydroxydiaryl such as bis (3,5-dimethyl-4-hydroxyphenyl) sulfone; Dihydroxydiaryl ethers such as sulfones and bis (4-hydroxyphenyl) ether; bis (3,5-dimethyl-4-hydroxyphenyl) ether, 4,4 ′
-Dihydroxybenzophenone; 3,3 ', 5,5'-
Dihydroxydiaryl ketones such as tetramethyl-4,4'-dihydroxybenzophenone, bis (4-hydroxyphenyl) sulfide; bis (3-methyl-4
Dihydroxydiaryl sulfides such as bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, dihydroxy diaryl sulfoxides such as bis (4-hydroxyphenyl) sulfoxide, and 4,4′-dihydroxy diphenyl Dihydroxydiphenyls such as 9,9-bis (4-
And dihydroxyarylfluorenes such as (hydroxyphenyl) fluorene. In addition to dihydric phenols, dihydroxybenzenes such as hydroquinone, resorcinol and methylhydroquinone;
And dihydroxynaphthalenes such as 2,6-dihydroxynaphthalene. These dihydric phenols and the like may be used alone or in combination of two or more. Also,
Examples of the carbonic acid diester compound include diaryl carbonates such as diphenyl carbonate and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate. In the present invention, the polycarbonate resin as the component (A) may contain a branched polycarbonate, if necessary. Examples of the branching agent used to obtain the above-mentioned branched polycarbonate include phloroglucin, melitic acid, trimellitic acid, trimellitic chloride, trimellitic anhydride, gallic acid, n-propyl gallate, protocatechuic acid, pyromellitic acid, and pyromellitic acid Anhydride, α-resorcinic acid, β-resorcinic acid, resorcinaldehyde, isatin bis (o-cresol), benzophenonetetracarboxylic acid;
4′-trihydroxybenzophenone; 2,2 ′, 4
4'-tetrahydroxybenzophenone; 2,4,4 '
-Trihydroxyphenyl ether; 2,2 ', 4
4'-tetrahydroxyphenyl ether; 2,4
4'-trihydroxydiphenyl-2-propane; 2,
2′-bis (2,4-dihydroxyphenyl) propane; 2,2 ′, 4,4′-tetrahydroxydiphenylmethane; 2,4,4′-trihydroxydiphenylmethane; 1- [α-methyl-α- (4 '-Dihydroxyphenyl) ethyl] -3- [α', α'-bis (4 "-hydroxyphenyl) ethyl] benzene; 1- [α-methyl-α- (4'-dihydroxyphenyl) ethyl] -4-
[Α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene; α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene; 2,6-bis (2-hydroxy-5'-methylbenzyl) -4-methylphenol; 4,6-dimethyl-
2,4,6-tris (4'-hydroxyphenyl) -2
-Heptene; 4,6-dimethyl-2,4,6-tris (4'-hydroxyphenyl) -heptane; 1,3,5
-Tris (4'-hydroxyphenyl) benzene; 1,
1,1-tris (4-hydroxyphenyl) ethane;
2,2-bis [4,4-bis (4′-hydroxyphenyl) cyclohexyl] propane; 2,6-bis (2′-
(Hydroxy-5'-isopropylbenzyl) -4-isopropylphenol; bis [2-hydroxy-3-
(2'-hydroxy-5'-methylbenzyl) -5-methylphenyl] methane; bis [2-hydroxy-3-
(2'-hydroxy-5'-isopropylbenzyl)-
5-methylphenyl] methane; tetrakis (4-hydroxyphenyl) methane; tris (4-hydroxyphenyl) phenylmethane; 2 ′, 4 ′, 7-trihydroxyflavan; 2,4,4-trimethyl-2 ′, 4 ', 7-
Trihydroxyflavan; 1,3-bis (2 ′, 4′-
Dihydroxyphenylisopropyl) benzene; tris (4'-hydroxyphenyl) -amyl-s-triazine and the like. In some cases, a polycarbonate-polyorganosiloxane copolymer composed of a polycarbonate part and a polyorganosiloxane part may be used as the polycarbonate resin of the component (A). At this time, the degree of polymerization of the polyorganosiloxane portion is preferably 5 or more. In addition, as the polycarbonate resin as the component (A), for example, a linear aliphatic divalent carboxylic acid such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and the like may be used as a copolymer monomer. Copolymers can also be used. In addition, as a terminal stopper at the time of superposition | polymerization of a polycarbonate resin, various well-known things can be used. Specifically, examples of the monohydric phenol include phenol, p-cresol, pt-butylphenol, pt-octylphenol, p-cumylphenol, and nonylphenol. Furthermore, in order to enhance the flame retardancy, a copolymer with a phosphorus compound or a polymer whose terminal is blocked with a phosphorus compound can also be used. Further, in order to enhance the weather resistance, a copolymer with a dihydric phenol having a benzotriazole group can be used. The viscosity average molecular weight of the polycarbonate resin (A) used in the present invention is preferably 10,000 to 60,000, more preferably 15,000 to 45,000, and most preferably 18,000 to 35,000. When the viscosity average molecular weight is less than 10,000, the strength and heat resistance of the obtained resin composition are often insufficient. If the viscosity average molecular weight exceeds 60,000, the moldability is often insufficient. Such polycarbonate resins are used alone or in combination of two or more. 2
When used in combination of more than one kind, the combination is not limited. For example, those having different monomer units, different copolymerization molar ratios, and / or different molecular weights are arbitrarily combined. The thermoplastic polyester resin (B) used in the present invention is a thermoplastic polyester obtained by polycondensing a divalent or more carboxylic acid component, a divalent or more alcohol and / or a phenol component by a known method. It is. Specific examples of the thermoplastic polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polycyclohexane dimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Examples of the divalent or higher valent aromatic carboxylic acid component include divalent or higher valent aromatic carboxylic acids having 8 to 22 carbon atoms and ester-forming derivatives thereof. Specific examples of these include phthalic acid such as terephthalic acid and isophthalic acid, naphthalenedicarboxylic acid, bis (p
-Carboxyphenyl) methane, anthracenedicarboxylic acid, 4-4'-diphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic acid, diphenylsulfondicarboxylic acid, trimesic acid, trimellitic acid, pyro Carboxylic acids such as merit acid, and derivatives thereof having an ester-forming ability are exemplified.
These may be used alone or in combination of two or more.
Preferred are terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. This is because they are excellent in ease of handling, ease of reaction, physical properties of the obtained resin, and the like. Examples of the dihydric or higher alcohol and / or phenol component include an aliphatic compound having 2 to 15 carbon atoms, an alicyclic compound having 6 to 20 carbon atoms, and an aromatic compound having 6 to 40 carbon atoms.
Compounds having at least two hydroxyl groups, and ester-forming derivatives thereof, and the like can be given. Specific examples of such alcohol and / or phenol components include ethylene glycol, propylene glycol, butanediol, hexanediol, decanediol, neopentyl glycol, cyclohexanedimethanol, cyclohexanediol, 2,2′-bis (4- Examples thereof include compounds such as (hydroxyphenyl) propane, 2,2′-bis (4-hydroxycyclohexyl) propane, hydroquinone, glycerin, and pentaerythritol, and derivatives thereof having an ester-forming ability. Preferred alcohol and / or phenol components are ethylene glycol, butanediol, cyclohexanedimethanol. This is because the handleability, the ease of reaction, the physical properties of the obtained resin, and the like are excellent. In the thermoplastic polyester resin (B), a known copolymerizable component other than the above-mentioned acid component and alcohol and / or phenol component may be copolymerized as long as desired properties are not impaired. Examples of such a copolymerizable component include divalent or higher valent aliphatic carboxylic acids having 4 to 12 carbon atoms,
Examples thereof include carboxylic acids such as divalent or higher valent alicyclic carboxylic acids having 8 to 15 carbon atoms, and ester-forming derivatives thereof. Specific examples of these include adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, maleic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-
And dicarboxylic acids such as cyclohexanedicarboxylic acid, and derivatives thereof having an ester-forming ability. Also, oxy acids such as p-hydroxybenzoic acid and their ester-forming derivatives, cyclic esters such as ε-caprolactone, and the like can be used as the copolymerization component. Furthermore, polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) blocks and / or random copolymers, bisphenol A copolymerized polyethylene oxide addition polymers, propylene oxide addition polymers, tetrahydrofuran addition polymers, polytetraethylene A thermoplastic polyester resin in which a polyalkylene glycol unit such as methylene glycol or the like is partially copolymerized in a polymer chain can also be used. The copolymerization amount of the above components is approximately 20
% By weight, preferably 15% by weight or less, more preferably 10% by weight or less. (B) The thermoplastic polyester resin contains an alkylene terephthalate unit in an amount of preferably 80% by weight or more, more preferably 85% by weight or more.
It is a polyalkylene terephthalate having at least 90% by weight, most preferably at least 90% by weight. This is because the obtained composition has an excellent balance of physical properties (eg, moldability).
(B) 25% of a thermoplastic polyester resin in a phenol / tetrachloroethane = 1/1 (weight ratio) mixed solvent.
The logarithmic viscosity (IV) measured at 0 ° C is preferably 0.30 to 2.00 dl / g or more, preferably 0.40 to 1.80 dl / g, more preferably 0.5 to 1.80 dl / g.
0 to 1.60 dl / g. If the logarithmic viscosity is less than 0.30, the flame retardancy and mechanical strength of the molded article are often insufficient, and if it exceeds 2.00 dl / g, the molding fluidity tends to decrease. (B) The thermoplastic polyester resin can be used alone or in combination of two or more. When two or more kinds are used in combination, the combination is not limited. For example, those having different copolymer components and different molar ratios and / or those having different molecular weights are arbitrarily combined. In the present invention, the mixing ratio of the (A) polycarbonate resin and the (B) thermoplastic polyester resin is 100/0 to 50/50 by weight, preferably 95/5 to 55/45. And more preferably in the range of 90/10 to 60/40. (A)
If the weight ratio of the thermoplastic polyester resin (B) in the mixture of the polycarbonate resin and the thermoplastic polyester resin (B) exceeds 50, the impact resistance and the flame retardancy are undesirably reduced. When the weight ratio of the thermoplastic polyester resin (B) is less than 5, the moldability and solvent resistance of the obtained molded article may be reduced. The weight ratio of B) is preferably 5 or more. In the present invention, in order to impart flame retardancy without using chlorine or bromine, (C) melting point is 60 ℃ or more,
A phosphate ester-based flame retardant having a number average molecular weight of 400 or more is used. Specific examples include monophosphate esters, condensed phosphate esters, and modified products and mixtures thereof. More specifically, tri (di-2,6-
Xylenyl) phosphate, resorcinol bis (di-
2,6-xylenyl) phosphate, hydroquinone bis (di-2,6-xylenyl) phosphate, biphenylbis (di-2,6-xylenyl) phosphate, and condensed and modified products thereof. These phosphate ester flame retardants may be used alone or in combination of two or more. It is known that a phosphate ester-based flame retardant, when added to a composition, acts as a plasticizer for the composition, and thus significantly reduces the heat resistance of the composition. In order to minimize the decrease in heat resistance of the obtained composition,
(C) It is necessary to use a phosphate ester-based flame retardant having a melting point of 60 ° C. or more and a number average molecular weight of 400 or more. By using such a phosphate ester-based flame retardant, it is possible to impart high flame retardancy without sacrificing the high heat resistance inherent in the composition, and it is possible to impart impact resistance to the composition. Decreases in strength, thermal stability, chemical resistance, etc. can be minimized. (C) The melting point of the phosphate ester flame retardant must be 60 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 ° C. or higher.
° C or higher. When a phosphate ester having a melting point of less than 60 ° C. is used, the heat resistance of the composition is greatly reduced, and the impact strength and
Thermal stability, chemical resistance, and the like also tend to decrease, which is not preferable. (C) The number average molecular weight of the phosphate ester flame retardant must be 400 or more. Preferably 500
The number is more preferably 600 or more. Use of a phosphate ester having a number average molecular weight of less than 400 is not preferred because the heat resistance of the composition is greatly reduced and the impact strength, thermal stability, chemical resistance, and the like tend to be reduced. In addition, low molecular weight phosphate ester flame retardants generally have high volatility, and components volatilized during molding processing may be scattered as a gas or adhere to the mold and cause contamination of the mold. It is not preferable because there is. The number average molecular weight of the phosphate ester-based flame retardant was determined by dissolving the phosphate ester in a chloroform solution, separating it with a GPC measuring device, measuring the molecular weight distribution, and measuring the polystyrene of various molecular weights with known molecular weights. This is a value calculated by converting into a molecular weight based on the detection time-molecular weight relationship created from the above. The addition amount of the phosphate ester-based flame retardant (C) is 0.1 to 100 parts by weight based on 100 parts by weight of the resin composed of the polycarbonate-based resin (A) and the thermoplastic polyester-based resin (B).
It is 30 parts by weight, preferably 0.2 to 25 parts by weight, more preferably 0.3 to 20 parts by weight. (C) When the addition amount of the phosphate ester-based flame retardant is less than 0.1 part by weight, the effect of improving the flame retardancy and moldability is poor. , Heat resistance and solvent resistance tend to decrease. Zinc borate anhydride used for the purpose of improving the flame retardancy in the present invention (D) _{is, xZnO · yB 2 O 3 (} x, y are positive integers) is a compound represented by the. As specific examples, 2ZnO.3B ₂ O ₃ , 4ZnO.B
₂ O ₃ , and the like.

Further, zinc borate and / or zinc borate hydrate may be treated with a surface treating agent such as a silane coupling agent or a titanate coupling agent. Examples of the silane coupling agent include epoxy silane, amino silane, and vinyl silane. Examples of the titanate coupling agent include monoalkoxy type, chelate type, and coordinate type. In anhydrous zinc borate (D),
The proportion of particles having a particle size of 5 μm or less is preferably 70% by weight or more. The ratio of particles having a particle size of 5 μm or less is 70
If the amount is less than 10% by weight, the flame retardancy of the thin-walled molded product may be insufficient, and the impact strength of the entire composition tends to decrease.

In the present invention, the particle size is defined as the particle size when zinc borate anhydride (D) is regarded as a sphere or the diameter of a circle obtained by converting the two-dimensional projected area of the particle into a circle. Say. As a method of measuring the particle size, for example, a method of determining the particle size and the quantity by measuring the particle size distribution using a particle counter or the like after preparing the particles in a slurry of an appropriate solution, photographing the particles There is a method in which image processing is further performed to determine the particle size and the quantity thereof. There is no particular limitation on the method for obtaining zinc borate anhydride (D) in which the ratio of particles having a particle size of 5 μm or less is 70% by weight or more.
A method of selecting and obtaining particles by sieving through particles of μm or less, dispersing anhydrous zinc borate (D) in a dispersion medium such as water, and then separating the particles into particles exceeding 5 μm and particles of 5 μm or less A method of obtaining a zinc borate anhydride (D) satisfying the conditions by passing through a filter capable of being classified, classifying, and mixing the classified particles in a desired ratio, a method of classifying with a gas stream to obtain a target particle size, a gas stream And a method of classifying with a sieve. Zinc borate anhydride may become partially hydrated by absorbing water when stored and used in a normal environment. In addition, when producing an anhydride from zinc borate, depending on the production method, a part of the crystallization water may remain without being completely released. When having water of crystallization, water of crystallization is partially released at a high temperature such as during kneading or processing of the composition, and the released water promotes a hydrolysis reaction of the polycarbonate resin or the polyester resin. Since the thermal stability, mechanical strength, impact strength, flame retardancy, etc. of the composition may be reduced, when kneading the composition, the absorbed crystal water may be in a state as small as possible. desirable. However, even if a small amount of water of crystallization is present, the deterioration of the physical properties may be insignificant, so that a small amount of water of crystallization may be included. The amount of water of crystallization that can be contained is 100% by weight of zinc borate containing water of crystallization.
However, it is generally less than 10% by weight, preferably less than 5% by weight, more preferably less than 1% by weight, most preferably less than 0.1% by weight. The amount of the anhydrous zinc borate (D) is 100 parts by weight of the polycarbonate resin (A),
Alternatively, based on a total amount of 100 parts by weight of the polycarbonate resin (A) and the polyester resin (B),
The amount is 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight, and most preferably 2 to 5 parts by weight. If the amount is less than 0.1 part by weight, the flame retardancy is insufficient, and if it exceeds 50 parts by weight,
This is not preferred because the impact strength of the composition tends to decrease. Zinc borate anhydride (D) may be used alone,
Two or more kinds may be used in combination. When two or more types are used in combination, the combination is not particularly limited. In the present invention, (E) (E1) silicone, (E2) silicate compound,
(E3) By using one or more compounds selected from fluorine-based resins in combination, it is possible to prevent a dripping phenomenon that occurs during a combustion test and to impart high flame retardancy even to a thin-walled molded product. As the component (E), the components (E1) to (E3) may be used alone, or any two of the components (E1) to (E3) may be used in combination. May be used. (E1) used in the present invention
There is no particular limitation on silicone, for example, R ₃ Si
O _0.5 , R ₂ SiO, RSiO _1.5 , R′R ₂ SiO _0.5 ,
_{R'RSiO, R '2 SiO, R'SiO} 1.5, SiO 2
A unit and a mixture thereof, wherein R is independently a substituted or unsubstituted, saturated or unsaturated monovalent hydrocarbon group, R ′ is each independently the same as R or a hydrogen atom,
Represents a group such as hydroxyl, alkoxyl, aryl, vinyl, allyl, etc., and a part of R and R 'groups is an epoxy group, an amino group, a hydroxyl group, a carboxyl group, a mercapto group, a vinyl group, a phenol group, an acryl group , Which may be substituted with a reactive group such as a methacryl group), a liquid, a gum, a varnish, a powder, and a flake having chemically bonded siloxy units composed of units represented by And the like. Specific examples include polydimethylsiloxane, polymethylphenylsiloxane, and polydiorganosiloxane having R ₂ SiO as a main structural unit, such as polydiphenylsiloxane, and some of the hydrogen atoms contained in the hydrocarbon group of the polydiorganosiloxane are epoxy. Group, amino group, hydroxyl group, carboxyl group, mercapto group, vinyl group, phenol group, acrylic group, modified polydiorganosiloxane substituted with reactive group such as methacryl group, polymethylsilsesquioxane, polymethylphenylsilsesqui R such as oxane
Examples thereof include polyorganosilsesquioxane having SiO _1.5 as a main constituent unit, silicone resin having R ₃ SiO _0.5 unit and SiO ₂ unit as main constituent components, and polyorganosiloxane rubber having rubber elasticity. The amount of the silicone (E1) used is 0.1 to 50 parts by weight based on 100 parts by weight of the total of the polycarbonate resin (A) and the thermoplastic polyester resin (B),
Preferably 0.1 to 40 parts by weight, more preferably 0.1 to 40 parts by weight.
5 to 30 parts by weight. If the amount is less than 0.1 part by weight, the flame retardancy is insufficient, and if it exceeds 50 parts by weight,
Since the mechanical strength of the flame retardant resin composition of the present invention tends to decrease, it is not preferable. The silicone (E1) may be used alone or in combination of two or more.
When two or more types are used in combination, the combination is not particularly limited. The (E2) silicate compound used in the present invention has an effect of improving the flame retardancy. In addition, the addition of the silicate compound can improve the heat resistance and the elastic modulus. it can. Such a silicate compound is typically a compound having a chemical composition of SiO2 units. Although the shape is not particularly limited, it is typically in the form of powder, granule, needle, plate, or the like. These silicate compounds may be natural products or synthesized products. Specific examples of the silicate compound include magnesium silicate, aluminum silicate, calcium silicate, talc, mica, wollastonite, kaolin, diatomaceous earth, and smectite. Among them, mica, talc, kaolin, and smectite are excellent in the effect of remarkably increasing the flame retardancy of the molded product, and also have the effect of suppressing the anisotropy of the molded product when it is formed, as well as its heat resistance and mechanical properties. It is preferable because it also has an excellent effect of improving strength. These may be used alone or in combination of two or more. When two or more types are used in combination, the combination is not particularly limited. The silicate compound (E2) may be treated with a surface treatment agent such as a silane coupling agent or a titanate coupling agent. Examples of the silane coupling agent include epoxy silane, amino silane, and vinyl silane. Examples of the titanate coupling agent include monoalkoxy type, chelate type, and coordinate type. The above (E2)
The addition amount of the silicate compound is 0.1 to 100 parts by weight based on 100 parts by weight of the resin composed of the polycarbonate resin (A) and the thermoplastic polyester resin (B).
Preferably 0.2 to 70 parts by weight, more preferably 0.1 to 70 parts by weight.
It is 3 to 50 parts by weight. (E2) When the added amount of the silicate compound is less than 0.1 part by weight, the obtained molded article has poor flame retardancy improving effect, and when it exceeds 100 parts by weight, the impact resistance of the obtained molded article, Thermal stability and surface properties decrease,
There is a tendency that handling becomes difficult such as kneading with the resin during melt kneading becomes difficult. The fluororesin (E3) used in the present invention is a resin having a fluorine atom. Specific examples include polymonofluoroethylene, polydifluoroethylene, polytrifluoroethylene, polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, and polyvinylidene fluoride. be able to. Further, if necessary, the monomer used in the production of the fluororesin and the copolymerizable monomer may be used in combination to polymerize, if necessary, to the extent that physical properties such as flame retardancy of the obtained molded article are not impaired. The obtained copolymer may be used. One of these fluorine resins may be used alone, or two or more thereof may be used in combination. The molecular weight of the fluororesin is 1,000,000 to 2000
It is preferably 10,000, and more preferably 2,000,000 to 10,000,000. The method for producing these fluororesins can be obtained by a generally known method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. The fluorinated resin (E3) is preferably a fluorinated polyolefin resin, and more preferably a fluorinated polyolefin resin having an average particle size of 700 μm or less. Here, the average particle size refers to an average particle size of secondary particles formed by aggregation of primary particles of a fluorinated polyolefin resin. Furthermore, the ratio of density to bulk density (density /
It is a fluorinated polyolefin resin having a bulk density of 6.0 or less. Here, the density and the bulk density are JIS-K68
This was measured by the method described in No. 91. The fluororesin (E3) may be used alone or in combination of two or more. When two or more kinds are used in combination, the combination is not limited. For example,
Any of different types may be used arbitrarily. The amount of the fluororesin (E3) used is the polycarbonate resin (A)
And total amount of thermoplastic polyester resin (B) 10
0.005 to 5 parts by weight, preferably 0.01 to 1 part by weight, and more preferably 0.02 parts by weight with respect to 0 parts by weight.
0.5 part by weight. If the amount used is less than 0.005,
The effect of improving the flame retardancy is small, and if it exceeds 5 parts by weight, the molding fluidity and the surface appearance of the molded article of the flame retardant resin composition of the present invention tend to decrease. In the present invention, in order to improve the impact strength, toughness, chemical resistance, and the like of the obtained molded article, one or more resins selected from (F) a rubbery polymer and an olefin resin are used. As these resins, those having at least one glass transition point at 0 ° C. or lower, more preferably −20 ° C. or lower are preferable in order to improve the impact strength of the obtained resin. Among the components (F), examples of the rubbery polymer include diene rubbers such as polybutadiene, styrene-butadiene rubber, acrylonitrile-butadiene rubber, alkyl (meth) acrylate-butadiene rubber, acrylic rubber, and ethylene-propylene rubber. And siloxane rubbers, or copolymers thereof with other compounds copolymerizable therewith, and the like. In order to increase the compatibility between these elastic bodies and the polycarbonate resin (A) and the thermoplastic polyester resin (B) and to increase the impact strength of the obtained composition, it is necessary to add a vinyl monomer to the elastic body as described above. It is preferable to use a graft rubber obtained by graft polymerization of a polymer.
Vinyl monomers used for graft polymerization include aromatic vinyl compounds, vinyl cyanide compounds, alkyl (meth) acrylates, and other vinyl compounds that can be graft-polymerized to rubber-like elastic materials. is there. As the aromatic vinyl compound, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-
Methylstyrene, vinyltoluene, and the like. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Examples of the alkyl (meth) acrylate include butyl acrylate, butyl methacrylate, ethyl acrylate, ethyl methacrylate, methyl acrylate, and methyl methacrylate. Other vinyl compounds include acrylic acid, methacrylic acid, etc., unsaturated acids, glycidyl acrylate, glycidyl methacrylate, etc. (meth) acrylic acid glycidyl ester, vinyl acetate,
Maleic anhydride, N-phenylmaleimide, and the like. The copolymerization ratio at the time of copolymerizing the elastic body and the vinyl compound is not particularly limited, but a preferable ratio for further increasing the impact strength is 10/90 to 90 / by weight.
10, and 30/70 to 80/20. When the weight ratio of the elastic body is less than 10, the effect of improving the impact resistance is reduced. If it exceeds 90, the compatibility with the resins (A) and (B) tends to decrease. As another means for increasing the compatibility between these elastic bodies and the polycarbonate resin (A) and the thermoplastic polyester resin (B) and increasing the impact strength of the obtained composition, the above-mentioned elastic bodies may be made of a hydroxyl group, Those modified with functional groups such as a carboxyl group, a carbonyl group, an acid anhydride group, an epoxy group and an oxazoline group can be used. As a method for modifying an elastic body, a method of copolymerizing a compound having a functional group, or a method of introducing a functional group by reacting the double bond as a reaction point when the elastic body has a double bond. And the like. Examples of the method for copolymerizing the functional group include a method for copolymerizing (meth) acrylic acid, alkyl (meth) acrylate, maleic anhydride, glycidyl (meth) acrylate, and the like. As the copolymerization method, various known polymerization methods can be used. Examples of a method for introducing a functional group by a reaction include a method of epoxidizing a double bond with a peroxide such as peracetic acid. As the reaction method, any known method can be used. (F)
Among them, olefin-based resins are, in addition to polyolefins in a narrow sense, polydienes, mixtures of two or more thereof, copolymers of two or more olefin monomers and diene monomers, copolymerizable with olefin monomers and olefins. It is used as a broad concept including a copolymer of one or more other vinyl monomers. For example, ethylene, propylene, 1-butene, 1-pentene, isobutene, butadiene, isoprene, phenylpropadiene, cyclopentadiene, 1,5-norbornadiene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, 1,5 -Cyclooctadiene, 1,3-
Homopolymers or copolymers selected from one or a combination of two or more of monomers such as cyclooctadiene, α, ω-non-conjugated dienes, and further, these homopolymers and copolymers A mixture composed of the above mixture is exemplified. Among them, polyethylene, polypropylene and the like are preferably used because the chemical resistance of the obtained composition is improved. Further, these olefin components and (meth) acrylic acid, alkyl (meth) acrylate, glycidyl (meth) acrylate, vinyl acetate, maleic anhydride, N-phenylmaleimide,
It may be a copolymer of an olefin such as carbon monoxide and a vinyl monomer copolymerizable therewith. A specific example of these copolymers is polyethylene.
(Meth) acrylic acid alkyl ester copolymer, ethylene / (meth) acrylic acid alkyl ester / carbon monoxide copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate copolymer, ethylene / glycidyl Methacrylate / (meth) acrylic acid alkyl ester copolymer, ethylene
Vinyl acetate copolymer, ethylene / vinyl acetate / carbon monoxide copolymer, ethylene / (meth) acrylic acid copolymer,
Examples thereof include an ethylene / maleic anhydride copolymer and an ethylene / maleic anhydride / N-phenylmaleimide copolymer. Equivalent copolymers can be produced with other olefin resins. The method for polymerizing these polyolefin resins is not particularly limited, and can be polymerized by various methods. As long as it is polyethylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and the like can be obtained by a polymerization method, and any of them can be preferably used. By adding the graft copolymer and the olefin resin in combination as (F),
The various effects described above can be further enhanced.
(F) The addition amount of the resin is a polycarbonate resin (A)
And resin 10 comprising thermoplastic polyester resin (B)
0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, most preferably 0.1 to 20 parts by weight, based on 0 parts by weight.
It is 3 to 10 parts by weight. If the amount is less than 0.1 part by weight, the effect of improving the impact resistance of the composition is small, and if the amount is more than 20 parts by weight, the resulting composition is unfavorably deteriorated in flame retardancy, rigidity, heat resistance and the like. The flame-retardant resin composition of the present invention further includes any other thermoplastic or thermosetting resin within a range that does not impair the present invention, for example, an unsaturated polyester resin,
Polyamide resin, polystyrene resin, acrylonitrile / styrene compound copolymer, polyalkyl (meth) acrylate resin, polyphenylmaleimide resin, polyphenylene sulfide resin, polyphenylene ether resin, polyacetal resin, polysulfone resin, May be added alone or in combination of two or more. Further, in order to make the flame-retardant resin composition of the present invention a higher-performance one, an antioxidant such as a phenol-based antioxidant, a thioether-based antioxidant, a heat stabilizer such as a phosphorus-based stabilizer, and the like. Are preferably used alone or in combination of two or more. Further, if necessary, generally well-known stabilizers, lubricants, release agents, plasticizers, non-phosphorus-based flame retardants, flame retardant aids, ultraviolet absorbers, light stabilizers, pigments, dyes, antistatics Additives such as an agent, a conductivity imparting agent, a dispersant, a compatibilizer, and an antibacterial agent can be used alone or in combination of two or more. The method for producing the composition of the present invention is not particularly limited. For example, it can be produced by a method of drying and kneading the above components, other additives, resins, etc., and then using a melt kneading machine such as a single screw or twin screw extruder. When the compounding agent is a liquid, it can be produced by adding the compounding agent to the extruder midway using a liquid supply pump or the like. The molding method of the thermoplastic resin composition produced by the present invention is not particularly limited, and molding methods generally used for thermoplastic resins, for example, injection molding, blow molding, extrusion molding, vacuum molding, press Molding, calendar molding, etc. can be applied.

[0008]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. In the following, “parts” means parts by weight and “%” means% by weight, unless otherwise specified. The evaluation of the resin composition was performed by the following method. Evaluation method The obtained pellet was dried at 120 ° C. for 4 hours, and then dried at 150 ° C.
t Using an injection molding machine, at a cylinder temperature of 280 ° C. and a mold temperature of 50 ° C., a thickness of 1.6 mm, 2.5 mm, 3.2 m
m, bar (width 12 mm, length 127 mm), 150 m
A flat plate having an m square and a thickness of 2.5 mm was obtained, and the following evaluation was performed. Flame retardancy: Flame retardancy of a 1.6 mm thick bar was evaluated by a V test according to UL-94 standard. In this evaluation, the flame retardancy was V-
For those having a rating of 0 or V-1, UL-9
Flame retardancy was evaluated by a 5 V test using a 2.5 mm thick bar and a 150 mm square 2.5 mm thick flat plate according to the 4 standards. Impact resistance: Using a 3.2 mm thick bar, ASTM D-
According to 256, notched IZOD impact strength was measured at 23 ° C. to evaluate impact resistance. Heat resistance: ASTM D-6 using 6.4 mm thick bar
According to No. 48, HDT with a load of 0.45 MPa was measured. Example 1 A polyethylene terephthalate resin (B1) 2 polymerized using 80 parts of a bisphenol A type polycarbonate resin (A1) having a viscosity average molecular weight of about 23500 and germanium dioxide having an logarithmic viscosity of about 0.75 dl / g.
0 parts of a phosphate ester-based flame retardant represented by the following formula 1 (C
1) (melting point 96-97 ° C, number average molecular weight 700) 7.5
Zinc borate anhydride (D1) having a mean particle size of 2 μm and a particle size exceeding 5 μm, which is represented by 2ZnO · 3B ₂ O ₃ and has no crystallization water (D1) (fire brake 500f
ine: US Borax brand name) 3 parts, average particle size 13
μm of talc (E2-1) (talcan PK: trade name of Hayashi Kasei) 0.5 part, polytetrafluoroethylene (E3-
1) (Polyflon FA-500: trade name, manufactured by Daikin)
0.3 parts, graft copolymer rubber (F1) obtained by graft copolymerizing methyl methacrylate with polybutadiene (EXL
-2602: 4 parts of Kureha Chemical Co., Ltd., 0.2 parts of HP-10 (trade name of Asahi Denka), a phosphite stabilizer, and AO-60, a phenolic stabilizer, as a stabilizer.
(Asahi Denka brand name) After dry blending 0.2 parts, the cylinder temperature was set to 260 ° C with vent 2
Screw extruder [TEX44: trade name, manufactured by Japan Steel Works, Ltd.]
And the mixture was melt-extruded to obtain a resin composition.

[0009]

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(N = 0-2) Table 1 shows the evaluation results of the resin composition. Examples 2 to 18: Resin compositions were obtained in the same manner as in Example 1 except that the amounts of each compounding agent were changed to those shown in Tables 1 and 2. However, the following compounding agents were used. The evaluation results are shown in Tables 1 and 2. (A) As a polycarbonate resin ・ A bisphenol A type polycarbonate resin having a viscosity average molecular weight of about 26500 (A2) (B) As a thermoplastic polyester resin ・ A polyethylene terephthalate resin (B2) having a logarithmic viscosity of 0.6 ・ A logarithm Polybutylene terephthalate resin having a viscosity of 0.85 (B3) (C) As an organic phosphorus-based flame retardant: Phosphate ester (C2) represented by the following formula 2. Melting point 1
68-169 ° C, number average molecular weight 700

[0011]

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(N = 0 to 2) A phosphoric ester (C3) represented by the following formula 3: Melting point 1
82-183 ° C, number average molecular weight 780

[0013]

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(N = 0 to 2) tris (2,6 dimethylphenyl) phosphate (C
4) Melting point: 136 to 138 ° C., number average molecular weight: 410 (PX
-130: As Daihachi Chemical trade name) (D) zinc borate anhydride, represented by _{· 4ZnO · B 2 O 3 ·} H 2 O, the water of crystallization 4.5
Zinc borate having an average particle diameter of 5 to 10 μm having weight% (Firebrake 415: trade name, manufactured by US Borax)
Zinc borate (ZB1) having a particle size of 5 μm or less through a sieve having an opening of 5 μm, and zinc borate (ZB) having a particle size of more than 5 μm.
B2) and (ZB1) was used. (ZB1) is 99% of particles having a particle size of 5 μm or less, and has an average particle size of about 2 μm.
Met. On the other hand, for (ZB2), particles having a particle size of 5 μm or less were 1%, and the average particle size was 12 μm. (D2): about ₂ % by weight of particles having a mean particle size of 8 μm and 5 μm, which is represented by 2ZnO.3B ₂ O ₃ and has substantially no water of crystallization,
Contained zinc borate anhydride (D3) (E1) Silicone: Silicone (E1-1) [Si powder DC4-70
51: Toray Dow Corning Silicone product name] (E2) As a silicate compound, mica [A-21S: Yamaguchi mica product name] (E2-
2) (F) As a resin selected from a rubber-like elastic body and an olefin resin, a graft copolymer obtained by copolymerizing an alkyl (meth) acrylate with an elastic body in which acrylic rubber and silicone rubber are intertwined with each other. Combined (F2) (METABLEN S-2
001: trade name of Mitsubishi Rayon) Ethylene / ethyl acrylate copolymer [ethyl acrylate content = 35% by weight] (F3) (EEA A7)
09: trade name of DuPont-Mitsui Polychemicals) ・ Ethylene / methyl acrylate / glycidyl methacrylate copolymer [methyl acrylate content = 30% by weight, glycidyl methacrylate content = 6% by weight] (F
4) (Bond First 7M: trade name, manufactured by Sumitomo Chemical Co., Ltd.)-Linear low density polyethylene (F5) (Moretech 016)
8N: trade name of Idemitsu Petrochemical Co., Ltd. Comparative Examples 1 to 10 Example 1 except that each compounding agent was changed to the amount shown in Table 3.
In the same manner as in the above, a resin composition was obtained. Table 3 shows the evaluation results. The following compounding agents were used except for those shown in the examples. (C ′): triphenyl phosphate (C′1) (Rheofos T
PP: trade name, manufactured by Ajinomoto) melting point 47-48 ° C, number average molecular weight 325 ・ phosphate ester (C'2) represented by the following formula 4. Liquid at room temperature, number average molecular weight 770

[0015]

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[0016] (n = 0~2) (D ' ) is indicated by _{· 2ZnO · 3B 2 O 3 ·} 3.5H 2 O as, zinc borate having an average particle size of 5~10μm having about 19 wt% water of crystallization (D'1) (Fire brake 290: trade name, manufactured by US Borax) In Comparative Example 1, since (D) zinc borate was not added, the flame retardancy was significantly reduced. In Comparative Example 2, when the amount of the (C) phosphate ester-based flame retardant was increased to supplement the flame retardancy of Comparative Example 1, the heat resistance was significantly reduced. In Comparative Example 3, since the ratio of (A) polycarbonate resin / (B) polyester resin is out of the range of the present patent, flame retardancy, heat resistance, and impact resistance are all reduced. In Comparative Examples 4 and 5, since the type of the (C) phosphate ester-based flame retardant is out of the range of the present patent, the heat resistance decreases in Comparative Example 4, and the heat resistance decreases in Comparative Example 5 as compared with Comparative Example 4. Although small, the impact resistance is greatly reduced. In Comparative Example 6, since the (D) zinc borate used was out of the range of the present patent, the impact resistance was reduced. In Comparative Example 7, since no compound (E) was added, the flame retardancy was reduced. In Comparative Example 8, since the compound (F) was not added, the impact resistance was reduced. In Comparative Example 9, since the (C) phosphate-based flame retardant was not added, the flame retardancy was significantly reduced. As is clear from the comparison between Tables 1 and 2 as Examples and Table 3 as Comparative Examples, all of the compositions of the present invention have flame resistance, impact resistance and solvent resistance. It can also be seen that they are excellent in wet heat resistance and heat stability.

[0017]

Industrial Applicability The flame-retardant resin composition of the present invention has a higher heat resistance than a conventionally known thermoplastic resin composition which is flame-retarded without using a compound of chlorine or bromine. High impact resistance, solvent resistance, moldability, heat stability,
A composition having excellent flame retardancy can be provided.
These are very useful industrially.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C08L 83:04 27:12 21:00 23:00 67:02) F term (reference) 4J002 AC024 BB014 BB103 BB103 BB154 BD123 BD133 BD143 BD153 BG044 BK004 BN064 BN124 BN144 BN174 CF012 CF042 CF052 CF062 CF072 CF082 CF142 CG011 CG021 CP033 CP034 CP053 CP063 CP093 CP103 CP143 CP163 CP171 CQ015 DJ008 FB 138 138 FB 137 FB 137 FB 007

Claims (3)

[Claims] (A) a polycarbonate resin and (B)
For 100 parts by weight of a resin composition comprising a thermoplastic polyester resin and having a weight ratio (A) / (B) of 100/0 to 50/50, (C) a melting point of 60 ° C. or more,
Phosphate ester flame retardant having a number average molecular weight of 400 or more 0.1 to 30 parts by weight (D) The amount of crystallization water contained is 1
0.1 to 50 parts by weight of zinc borate anhydride which is less than 0% by weight, and (E) one or more compounds selected from the following (E1) to (E3) (E1) 0.1 to 50 parts by weight of silicone ( E2) 0.1 to 100 parts by weight of a silicate compound (E3) 0.005 to 5 parts by weight of a fluorinated resin (F) One or more resins selected from rubbery polymers and olefinic resins 0.1 to 20 parts by weight A flame-retardant thermoplastic resin composition obtained by adding a part. 2. The flame-retardant thermoplastic resin composition according to claim 1, wherein 70% by weight or more of (D) zinc borate anhydride is particles having a particle size of 5 μm or less. 3. The thermoplastic polyester resin (B),
3. The flame-retardant thermoplastic resin composition according to claim 1, which is a polyalkylene terephthalate having an alkylene terephthalate unit of 80% by weight or more.