KR100433573B1 - Flame Retardant Thermoplastic Resin Composition - Google Patents

Abstract

Flame retardant thermoplastic resin composition of the present invention (A) 30-95 parts by weight of polycarbonate resin; (B) (b ₁ ) styrene, α-methylstyrene, halogen or methyl ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters, acrylonitrile, methacrylonitrile 5-95% by weight of maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide or mixtures thereof (b ₂ ) grafted to 5-95% by weight of polyorganosiloxane / polyalkyl (meth) acrylate rubber composite 1-50 parts by weight of the silicone / acrylate rubber modified graft copolymer obtained by polyhedral polymerization; (C) 50-95% by weight of (c ₁ ) styrene, α-methylstyrene, ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters or mixtures thereof and (c ₂ ) Acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimides or mixtures thereof 1-50 parts by weight of a vinyl copolymer prepared by copolymerizing 5-50% by weight; (D) 1-30 parts by weight of a phosphate ester compound, based on 100 parts by weight of the base resin comprising (A) + (B) + (C); And (F) 0.05-5 parts by weight of a fluorinated polyolefin resin having an average particle size of 0.05-1000 μm and a density of 1.2-2.3 g / cm ³ .

Description

Flame Retardant Thermoplastic Resin Composition

Field of invention

The present invention relates to a flame retardant thermoplastic resin composition. More specifically, the present invention relates to a flame retardant thermoplastic resin composition comprising a polycarbonate resin, a silicone / acrylate rubber modified graft copolymer, a vinyl copolymer, a phosphate ester flame retardant, and a fluorinated polyolefin resin.

Background of the Invention

Polycarbonate resins are excellent in transparency, mechanical strength and heat resistance, and are widely used in applications such as electric, electronic products, and automobile parts. However, polycarbonate resins are used in blends with other types of resins in order to improve them since they have disadvantages of poor processability and notched impact strength. For example, the blend of the polycarbonate resin and the rubber-modified styrenic copolymer may be referred to as a resin mixture having improved processability while maintaining high notch impact strength.

Since such polycarbonate-based blend resin compositions are typically applied to large injection moldings such as computer housings or other office equipment, they must maintain high mechanical strength, together with flame retardancy.

In order to impart flame retardancy to such a resin composition, a halogen-based flame retardant and an antimony compound have been conventionally used. U.S. Patent Nos. 4,983,658 and 4,883,835 disclose examples of using halogen containing compounds as flame retardants. However, when using a halogen flame retardant, there exists a problem that the gas which arises at the time of combustion is harmful to a human body. Therefore, the demand for resins that do not contain halogen-based flame retardants has recently been expanding rapidly.

As a technique for imparting flame retardancy without using a halogen flame retardant, the most common at present is to use a phosphate ester flame retardant.

U.S. Patent No. 4,692,488 discloses thermoplastic resin compositions consisting of non-halogen aromatic polycarbonate resins, non-halogen SAN (styrene-acrylonitrile) copolymers, non-halogen phosphorus compounds, tetrafluoroethylene polymers and small amounts of ABS copolymers. have.

U.S. Patent No. 5,030,675 also discloses flame retardant resin compositions composed of aromatic polycarbonate resins, ABS copolymer resins and polyalkylene terephthalate resins, monomeric phosphoric acid esters and fluorinated polyolefins.

Oligomeric phosphate ester compounds are also known to be used as flame retardants, and Japanese Patent Laid-Open No. 59-202,240 discloses a method for preparing such compounds. It is also mentioned that the compounds can be used as flame retardants for polyamide or polycarbonate resins.

However, phosphate ester compounds greatly increase the flame retardancy of polycarbonate resins, but do not improve the flame retardancy of styrene resins such as SAN copolymers or ABS copolymers. Therefore, in order to exhibit flame retardancy of the polycarbonate-based resin composition containing the styrene-based resin, a polyphosphate ester compound having a much higher or higher content than the styrene-based resin should be used as the flame retardant.

However, when increasing the content of the polycarbonate to obtain the flame retardancy of the polycarbonate-based resin composition containing the styrene resin, the flowability is reduced due to the high melt viscosity of the polycarbonate to increase the processability which is a disadvantage of the polycarbonate In order to blend the styrene-based resin, there is a problem that the meaning of the purpose of use is reduced. .

On the other hand, when the content of the styrene-based resin is increased to improve the flowability of the resin composition, the content of the flame retardant is increased, and at this time, a sudden decrease in the heat resistance of the resin composition occurs due to low heat resistance of the flame retardant.

In order to solve the above problems, the present inventors apply a polycarbonate resin, a silicone / acrylate rubber modified graft copolymer, a vinyl copolymer, a phosphate ester flame retardant, and a fluorinated polyolefin resin to provide an excellent film suitable for thin film molding. It is to develop a thermoplastic resin composition having fluidity, excellent flame retardancy, and excellent impact resistance, thermal stability, heat resistance, workability and appearance characteristics.

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

Another object of the present invention is to provide a thermoplastic resin composition having excellent balance of physical properties such as impact resistance, thermal stability, heat resistance, workability and appearance.

The above and other objects of the present invention can be achieved by the present invention described below.

The thermoplastic resin composition of the present invention is (A) 30-95 parts by weight of polycarbonate resin, (B) 1-50 parts by weight of silicone / acrylate rubber modified graft copolymer and (C) 1-50 parts by weight of vinyl-based copolymer 1-30 parts by weight of (D) phosphate ester flame retardant and (E) fluorinated polyolefin resin having an average particle size of 0.05-1000 µm and a density of 1.2-2.3 g / cm ³ with respect to 100 parts by weight of the basic resin. It consists of -5 parts by weight, the detailed description of each of these components is as follows.

(A) polycarbonate resin

The polycarbonate resin according to the present invention is prepared by reacting diphenols represented by the following formula (1) with phosgene, halogen formate or carbonic acid diester:

Wherein A is a single bond, alkylene of C _1-5 , alkylidene of C _2-5 , cycloalkylidene of C _5-6 , S or SO ₂ .

Examples of the diphenols represented by the above formula include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -propane, and 2,4-bis- (4- Hydroxyphenyl) -2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 2,2-bis- (3-chloro-4-hydroxyphenyl) -propane, 2,2 -Bis- (3,5-dichloro-4-hydroxyphenyl) -propane and the like. Among them, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, 1,1-bis- (4- Bisphenols, such as hydroxyphenyl) -cyclohexane, are preferable, and 2,2-bis- (4-hydroxyphenyl) -propane also called bisphenol-A is the most preferable.

The polycarbonate resin (A) of the present invention has a weight average molecular weight (M _w ) of 10,000 to 200,000, preferably 15,000 to 80,000. A branched polycarbonate resin may be used, and preferably, may be prepared by adding a compound having 0.05-2 mol% of a trivalent or more phenol group to the total amount of diphenols used in the polymerization.

The polycarbonate (PC) used in the preparation of the resin composition of the present invention may be used in the form of a homopolymer, a copolymer, or a mixture thereof. In addition, the polycarbonate resin (A) may be used in part or in whole by an aromatic polyester-carbonate resin obtained by polymerizing in the presence of an ester precursor, such as a bifunctional carboxylic acid. The polycarbonate resin (A) is used in the range of 30 to 95 parts by weight.

(B) Silicone / acrylate rubber modified graft copolymer

The silicone / acrylate rubber modified graft copolymer used in the present invention is (b ₁ ) styrene, α-methylstyrene, halogen or methyl ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, C _1-8 5-95% by weight of acrylic acid alkyl esters, acrylonitrile, methacrylonitrile, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide or mixtures thereof (b ₂ ) polyorganosiloxane / polyalkyl ( Meta) acrylate rubber composite Copolymer grafted to 5-95% by weight.

The C _1-8 methacrylic acid alkyl esters or C _1-8 acrylic acid alkyl esters are esters obtained from monohydryl alcohols containing 1 to 8 carbon atoms as esters of acrylic acid or methacrylic acid, respectively. Specific examples of these include methacrylic acid methyl ester, methacrylic acid ethyl ester, acrylic acid ethyl ester or methacrylic acid propyl ester, and among these, methacrylic acid methyl ester is particularly preferable.

The silicone / acrylate rubber modified graft copolymer (B) comprises a polyorganosiloxane / polyalkyl (meth) acrylate rubber composite (b ₂ ) in which a rubber made from an unsaturated acrylate monomer and a silicone rubber are complexed. having a core, a graft copolymer with a vinyl monomer (b ₁₎ to the core structure is a graft.

The polyorganosiloxane / polyalkyl (meth) acrylate rubber composite (b ₂ ) is preferably prepared by emulsion polymerization because it can easily control the size of the particles, first polymerized silicone rubber latex using an organosiloxane and a curing agent After the impregnation of the acrylate-based monomer into the rubber, the impregnated monomers can be prepared by polymerization.

The silicone rubber may be made from cyclosiloxane, and specific examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, and tetramethyl. Tetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, and the like.

By selecting one or more of the siloxane can be produced a silicone rubber, the content of which is 5-95 parts by weight based on 100 parts by weight of the total rubber composite. The curing agent used at this time includes trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, and the like, of which tetraethoxysilane is most suitable.

The acrylate rubbers include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, and the like. Of these, n-butyl acrylate is most suitable.

The acrylate rubber is prepared by impregnating an acrylate monomer into a silicone rubber and then polymerizing with a curing agent. The curing agent used at this time is ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate or 1,4-butylene glycol dimethacrylate, allyl methacrylate, or Triallyl cyanurate and the like. The content of the acrylate rubber is 5-95 parts by weight based on 100 parts by weight of the total rubber composite.

Hard shell by grafting at least one monomer selected from unsaturated compounds such as methyl methacrylate, styrene and acrylonitrile, which can be grafted to the polyorganosiloxane / polyalkyl (meth) acrylate rubber composite (b ₂ ) thus made. To produce a core-shell structured copolymer.

Preferred examples of the silicone / acrylate rubber modified graft copolymer (B) of the present invention include styrene, acrylonitrile and (meth) acrylic acid alkyl ester monomers alone or in the form of polydimethylsiloxane / polybutylacrylate rubber composites. The graft copolymerized thing is mentioned.

(C) vinyl copolymer

Examples of the vinyl copolymer (C) used in the production of the resin composition of the present invention include (c ₁ ) styrene, α-methylstyrene, ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, and C _1-8 acrylic acid. 50-95% by weight of alkyl esters or mixtures thereof and (c ₂ ) acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters, maleic anhydride, C Prepared by copolymerizing 5-50% by weight of _1-4 alkyl or phenyl N-substituted maleimide or mixtures thereof.

Said C _1-8 methacrylic acid alkyl esters or C _1-8 acrylic acid alkyl esters are esters obtained from monohydryl alcohols having 1 to 8 carbon atoms as esters of acrylic acid or methacrylic acid, respectively. As these specific examples, methacrylic acid methyl ester, methacrylic acid ethyl ester, acrylic acid ethyl ester, or methacrylic acid propyl ester is mentioned, Among these, methacrylic acid methyl ester is especially preferable.

The vinyl copolymer (C) used in the preparation of the resin composition of the present invention can be produced as a by-product in the preparation of the silicone / acrylate rubber modified graft copolymer (B), especially in an excess of a small amount of rubbery polymer. If the vinyl monomer of the graft or chain transfer agent (chain transfer agent) in excess of the use occurs more.

The content of the copolymer (C) used in the preparation of the resin composition of the present invention does not include a by-product of the graft copolymer (B).

In addition, the copolymer (C) used for manufacture of the resin composition of this invention is a thermoplastic resin and does not contain rubber | gum.

Preferred examples of the vinyl copolymer include those prepared by emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization using methacrylic acid methyl ester and (meth) acrylic acid methyl ester.

Other preferred vinyl copolymers include monomer mixtures of styrene and acrylonitrile and optionally methacrylic acid methylester, monomer mixtures of α-methylstyrene and acrylonitrile and optionally methacrylic acid methylester or styrene, α-methylstyrene And those prepared from monomer mixtures of acrylonitrile and optionally methacrylic acid methylester.

The styrene / acrylonitrile copolymer of component (C) of the present invention may be prepared by emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization, and it is preferable to use a weight average molecular weight of 15,000-200,000.

Another preferred copolymer (C) used in the preparation of the resin composition of the present invention is a copolymer of styrene and maleic anhydride, which can be produced using a continuous bulk polymerization method and a solution polymerization method. The composition ratio of the two monomer components can be varied in a wide range, preferably, the content of maleic anhydride is 5-25% by weight.

The molecular weight of the styrene / maleic anhydride copolymer, which is a vinyl copolymer (C), may also be used in a wide range, but it is preferable to use those having a weight average molecular weight of 60,000-200,000 and intrinsic viscosity of 0.3 to 0.9.

The styrene monomers used in the preparation of the vinyl copolymer (C) used in the preparation of the resin composition of the present invention are other substituted styrenes such as p-methylstyrene, vinyltoluene, 2,4-dimethylstyrene and α-methylstyrene. It can be used instead of the monomer.

The vinyl copolymer (C) of the present invention is used either alone or in the form of a mixture of two or more thereof.

(D) Phosphoric Acid Ester Compound

The phosphate ester compound used in the present invention is a phosphate ester compound represented by the following formula (2) or a mixture thereof:

Wherein R ₁ , R ₂ , R ₄ and R ₅ are each C ₆ -C ₂₀ aryl, alkyl-substituted C ₆ -C ₂₀ aryl groups or morphide groups; R ₃ is C ₆ -C ₃₀ aryl or an alkyl substituted C ₆ -C ₃₀ aryl group derivative; l represents the number average degree of polymerization, and the average value of l is 0 to 3.

In the formula, R ₁ , R ₂ , R ₄ and R ₅ is preferably a phenyl group or morphide group substituted with an alkyl group such as phenyl group, methyl, ethyl, isopropyl, t-butyl, isobutyl, isoamyl, t-amyl, etc. More preferably, a phenyl group or a morphide group in which a phenyl group, methyl, ethyl, isopropyl or t-butyl group is substituted, more preferably a phenyl group or a morphide group.

The phosphate ester compound (D) used in the present invention is a phosphate ester compound derived from a C ₆ -C ₃₀ aryl or an alkyl substituted C ₆ -C ₃₀ aryl group, and a C ₆ -C ₃₀ aryl or an alkyl substituted C ₆ As the -C ₃₀ aryl group, resorcinol, hydroquinone or bisphenol-A is preferred. That is, the phosphate ester type compound (D) used for this invention is an aryl derived phosphate ester whose average value of l is 0-3. In the present invention, a phosphate ester compound having a value of l of 0, 1, 2, and 3 may be used alone or in a mixed form, each of which is already mixed when prepared in a polymerization process, or separately prepared. It is possible to use a mixture of phosphate ester compounds having different l values.

In the phosphate ester compound, when the value of l is 0, tri (alkylphenyl) phosphate, di (alkylphenyl) monophenylphosphate, diphenylmono (alkylphenyl) phosphate, triphenylphosphate, diphenylmonopolyphosphate, Dimorpholide monophenyl phosphate, di (alkylphenyl) monomorpholide phosphate or dimorpholide mono (alkylphenyl) phosphate, and the like, these may be used alone or in a mixture of two or more.

In the present invention, the phosphate ester compound (D) is used as a flame retardant, and is used in an amount of 1-30 parts by weight based on the entire thermoplastic resin composition.

(E) fluorinated polyolefin resin

The fluorinated polyolefin resin (E) used in the preparation of the flame retardant thermoplastic resin composition of the present invention may be prepared using a known polymerization method, for example, a pressure of 7-71 kg / cm ² and a temperature of 0-200 ° C. , Preferably at 20-100 ° C., in an aqueous medium containing free radical forming catalysts such as sodium, potassium or ammonium peroxydisulfate.

Preferred specific examples of the fluorinated polyolefin resin (E) include polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene / vinylidene fluoride copolymer, tetrafluoroethylene / hexafluoropropylene copolymer And ethylene / tetrafluoroethylene copolymers, and the like, polytetrafluoroethylene having a particle size of 0.05-1,000 μm and specific gravity of 1.2-2.3 g / cm ³ is most preferred. These may be used independently from each other, and two or more different types may be used together.

When the fluorinated polyolefin resin is mixed with other component resins of the present invention and extruded, a fluorinated polyolefin-based resin forms a fibrillar network in the resin, thereby lowering the flow viscosity of the resin during combustion and increasing the shrinkage rate, thereby dropping the resin. It is to prevent the phenomenon.

The fluorinated polyolefin resin may be used in an emulsion state or a powder state. When the fluorinated polyolefin resin in an emulsion state is used, the dispersibility in the entire resin composition is good, but the manufacturing process is complicated. Therefore, even if it is powder state, if it can disperse | distribute suitably in the whole resin composition and can form a fibrous network, it is preferable to use it in powder state.

The content of the fluorinated polyolefin resin used in the production of the resin composition of the present invention is 0.05-5 parts by weight based on 100 parts by weight of (A) + (B) + (C).

The flame retardant thermoplastic resin composition of the present invention may include general additives such as impact modifiers, flame retardant aids, lubricants, mold release agents, nucleating agents, antistatic agents, stabilizers, reinforcing agents, inorganic additives, pigments, or dyes, depending on their respective applications, in addition to the above components. Can be.

The resin composition of the present invention can be produced by a known method for producing a resin composition. For example, the components of the present invention and other additives may be mixed simultaneously, then melt extruded in an extruder and prepared in pellet form.

The composition of the present invention can be used for molding a variety of products, and is particularly suitable for the manufacture of housings of electrical and electronic products, such as computer housings that require flame retardancy, bond strength and high impact resistance while being injected at high temperatures.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

(A) polycarbonate resin, (B) silicone / acrylate rubber modified graft copolymer, (C) vinyl copolymer, (D) (phosphate ester flame retardant and ( E) The specifications of fluorinated polyolefin resin are as follows.

(A) polycarbonate resin

PANLITE L-1250WP of TEIJIN, Japan was used as a bisphenol-A linear polycarbonate having a weight average molecular weight of 25,000 g / mol.

(B) Silicone / acrylate rubber modified graft copolymer

METABLEN RK-200 manufactured by MRC, Japan, in which styrene and acrylonitrile monomers were graft copolymerized into a silicone / acrylic rubber composite.

(B ') rubber modified graft copolymer

Butadiene rubber latex was added so that the butadiene content was 45 parts by weight based on the total amount of the monomer, 1.0 parts by weight of potassium oleate, 1.0 part by weight of cumene hydroperoxide 0.4 parts by weight, 0.3 parts by weight of mercaptan-based chain transfer agent was added to the reaction while maintaining at 75 ℃ for 5 hours to prepare an ABS graft latex. A 1% sulfuric acid solution was added to the resulting polymer latex, and after coagulation, dried to prepare a graft copolymer resin in a powder state.

(C) vinyl copolymer

A SAN copolymer resin was prepared by suspension polymerization by adding 0.2 parts by weight of azobisisobutyronitrile and 0.5 parts by weight of tricalcium phosphate, which are necessary additives to a mixture of 70 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 120 parts by weight of deionized water. . The copolymer was washed with water, dehydrated and dried to use a powdery SAN copolymer resin.

(D) Phosphate Ester Flame Retardant

(d ₁ ) Triphenylphosphate in which l = 0 in Formula 2 and R ₁ , R ₂ , and R ₅ are each a phenyl group was used.

(d ₂ ) In Formula 2, l = 0 is 3.4% by weight, l = 1 is 85.4% by weight, and the value of l is included in 11.1% by weight, and the average l = 1.0, R ₁ , R ₂ , Bisphenol-A derived oligomeric phosphate esters in which R ₄ and R ₅ are each a phenyl group were used.

(E) fluorinated polyolefin resin

Teflon (trade name) 7AJ of Dupont, USA was used.

Example 1-4

Each component of the composition shown in Table 1 and antioxidant were added, mixed in a conventional mixer and extruded using a twin screw extruder having L / D = 35 and Φ = 45 mm, and then the extrudate was prepared in pellet form.

Comparative Example 1-4

A specimen was prepared in the same manner as in Example 1-4 except that the rubber modified graft copolymer (B ′) was added instead of the silicone / acrylate rubber modified graft copolymer (B).

ingredient Example Comparative Example One 2 3 4 One 2 3 4 (A) Polycarbonate resin 60 60 60 50 60 60 70 60 (B) Silicone / acrylate rubber modified graft copolymer 8 12 10 10 - - - - (B ') rubber modified graft copolymer - - - - 10 10 15 10 (C) Styrene Copolymer 32 28 30 40 30 30 25 30 (D) Phosphate ester flame retardant (d ₁ ) 14 14 - - 14 - - 20 (d ₂ ) - - 20 20 - 20 20 - (F) Fluorinated polyolefin resin 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

(1) flame retardancy evaluation

Specimens for flame retardancy evaluation were prepared at 250 ° C. using a 10 oz injection machine. The flame retardancy was evaluated according to the UL-94 evaluation standard defined by the Underwriters Laboratory, and the combustion time and average combustion time when two flames were applied to five specimens were measured.

(2) general physical property measurement

Specimens for measuring the general physical properties were prepared using a 10 oz injection machine under the usual molding conditions at an injection temperature of 250 ℃. These specimens were left at 23 ° C. and 50% RH for 40 hours, and then impact strength was measured according to ASTM D256.

(3) heat resistance measurement

Heat resistance was evaluated by ASTM D1525.

The physical properties of the resins prepared in Examples 1-4 and Comparative Examples 1-4 are shown in Table 2. Example 1-4 is a case using the silicone / acrylate rubber modified graft copolymer (B) according to the present invention, Comparative Example 1-4 is a rubber instead of silicone / acrylate rubber modified graft copolymer (B) This is the case where the modified graft copolymer (B ') is not added.

Properties Example Comparative Example One 2 3 4 One 2 3 4 UL94 flame retardant (1/12 ″) V-0 V-0 V-0 V-0 fail fail V-2 V-0 Average burning time (seconds) 2.1 2.8 3.5 4.1 18.2 22.3 15.1 3.5 Maximum single burning time (sec) 4 4 6 8 33 45 21 6 Dropping water 0/5 0/5 0/5 0/5 1/5 2/5 1/5 0/5 Izod notch impact strength (1/8 ", kgcm / cm) 48 55 41 38 35 24 33 28 Heat resistance temperature (VST, ℃) 84 83 86 82 83 86 89 68

From the results of Table 2, when the silicone / acrylate rubber modified graft copolymer (B) is applied, excellent flame retardancy and improvement in heat resistance was observed at the same time. On the other hand, as shown in Comparative Examples 1-3, the silicone / acrylate rubber-modified graft copolymer (B) is not applied, and when the graft copolymer (B ') composed of butadiene rubber is used as the rubber of the core, under It was not possible to obtain the flame retardant rating specified in accordance with the UL-94 evaluation standard specified by the Underwriters Laboratory.

In addition, as shown in Comparative Example 4 when applying a large amount of the phosphorus-based flame retardant triphenyl phosphate (d ₁ ) it can be obtained the effect of improving the flame retardancy, but it was shown that the heat resistance sharply decreased. Since a general electrical and electronics housing requires a heat resistance temperature of 80 ° C. or more, when a large amount of triphenyl phosphate is added as a flame retardant, as in the case of Comparative Example 3, it was found to be unsuitable for the actual product application.

The present invention, by using a silicone / acrylate rubber modified graft copolymer, exhibits excellent flame retardancy and excellent fluidity, heat resistance, thermal stability, workability and appearance properties suitable for thin film molding, it is required flame retardancy and high heat resistance And flame retardant thermoplastic resin compositions useful for producing injection molded notebook computer housings, computer monitor housings or other office equipment where fluidity is required.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (3)

(A) 30-95 parts by weight of polycarbonate resin; (B) (b ₁ ) styrene, α-methylstyrene, halogen or methyl ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters, acrylonitrile, methacrylonitrile 5-95% by weight of maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimide or mixtures thereof (b ₂ ) grafted to 5-95% by weight of polyorganosiloxane / polyalkyl (meth) acrylate rubber composite 1-50 parts by weight of the silicone / acrylate rubber modified graft copolymer obtained by polyhedral polymerization; (C) 50-95% by weight of (c ₁ ) styrene, α-methylstyrene, ring-substituted styrene, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters or mixtures thereof and (c ₂ ) Acrylonitrile, methacrylonitrile, C _1-8 methacrylic acid alkyl esters, C _1-8 acrylic acid alkyl esters, maleic anhydride, C _1-4 alkyl or phenyl N-substituted maleimides or mixtures thereof 1-50 parts by weight of a vinyl copolymer prepared by copolymerizing 5-50% by weight; (D) 1-30 parts by weight of a phosphate ester compound, based on 100 parts by weight of the base resin comprising (A) + (B) + (C); And (F) 0.05-5 parts by weight of a fluorinated polyolefin resin having an average particle size of 0.05-1000 μm and a density of 1.2-2.3 g / cm ³ ; Flame-retardant thermoplastic resin composition, characterized in that consisting of. According to claim 1, wherein the silicone / acrylate rubber modified graft copolymer (B) is a polyorganosiloxane / polyalkyl (meth) acrylate rubber in the form of a composite of a rubber and a silicone rubber made from an unsaturated acrylate monomer A flame-retardant thermoplastic resin composition comprising a composite (b ₂ ) as a core and a vinyl monomer (b ₁ ) grafted to the core structure. The flame retardant thermoplastic resin composition according to claim 1, wherein the phosphate ester compound (D) is a phosphate ester compound represented by the following formula (2) or a mixture thereof. [Formula 2] Wherein R ₁ , R ₂ , R ₄ and R ₅ are each C ₆ -C ₂₀ aryl, alkyl-substituted C ₆ -C ₂₀ aryl groups or morphide groups; R ₃ is C ₆ -C ₃₀ aryl or an alkyl substituted C ₆ -C ₃₀ aryl group derivative; l represents the number average degree of polymerization, and the average value of l is 0 to 3.