JP6328404B2 - Styrenic flame retardant resin composition and molded article comprising the same - Google Patents

Description

Provided are a styrenic flame retardant resin composition having improved fluidity and heat resistance, and a molded article comprising the same.

Among petroleum-based resins, styrene-based resins are excellent in moldability, impact resistance and heat resistance, and their uses are diverse. Among them, general-purpose polystyrene and rubber-modified polystyrene are widely used in the fields of containers, packaging, daily necessities, etc., and flame-retardant polystyrene imparted with flame retardancy is OA equipment such as personal computers, printers, copying machines, It is used in the field of home appliances such as TV and audio.

Among them, in a device that is used in a large size or fixedly, since heat radiation increases as the internal mechanism becomes larger / complex, higher heat resistance is required. Furthermore, in recent years, the thickness and weight of molded products have been reduced, and a material that balances fluidity and heat resistance to a higher degree is required.

In addition, the exterior cover used on the outer surface of the device plays a role of preventing combustion, scattering of high-temperature substances, blowing of flame, and the like as a fireproof enclosure. Small materials can be used as long as they have UL94 V-1 flame retardant materials, but large flame retardants and devices that are used in a fixed manner require high flame resistance (UL94 5V). Is done.

Addition of a low molecular weight plasticizing component is a common technique for improving fluidity, but increasing the low molecular weight component reduces heat resistance, so fluidity and heat resistance are in a trade-off relationship. Thus, it is difficult for conventional materials to satisfy both requirements, and a resin composition that satisfies this requirement is awaited.

WO08 / 123240 Publication JP 2007-126520 A

In view of such a current situation, the present invention is to solve the above-mentioned problems and provide a resin composition having both improved fluidity and heat resistance, and a molded product comprising the same.

The present invention relates to (A) 100 parts by mass of a rubber-modified styrenic resin, (B) 10 to 20 parts by mass of a bromine-containing flame retardant, (C) 1 to 10 parts by mass of a flame retardant aid, (D) Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and is a block copolymer composed of styrene and 1,3-butadiene , comprising the following (A) component and (B) component, (I) It is a styrene flame-retardant resin composition containing 0.5 to 5 parts by mass of a block copolymer having a mass ratio of (b) component of 40 to 90/10 to 60 .
(A) A block copolymer comprising styrene and 1,3-butadiene having an Mw of less than 200,000
(B) A block copolymer comprising styrene and 1,3-butadiene having an Mw of 200,000 or more.

Moreover, this invention provides the molded object obtained by shape | molding the said resin composition.

Since the resin composition obtained by the present invention can improve both fluidity and heat resistance, it is advantageous to use it in the container / packaging field, OA equipment, home appliance parts and the like.

(D-1) is a GPC chart of a block copolymer of styrene and 1,3-butadiene.

The (A) rubber-modified styrenic resin used in the present invention is obtained by polymerizing an aromatic vinyl compound. If necessary, a conjugated diene rubber-like polymer may be added to perform rubber modification. Good. As the polymerization method, it can be produced by a known method, for example, a bulk polymerization method, a bulk / suspension two-stage polymerization method, a solution polymerization method or the like. As the aromatic vinyl compound monomer, known monomers such as styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene can be used, and styrene is preferable. In addition, monomers other than styrene-based monomers such as acrylonitrile, (meth) acrylic acid, (meth) acrylic acid ester and maleic anhydride which can be copolymerized with these aromatic vinyl compound-based monomers, What is necessary is just a grade which does not impair the performance of a styrene-type resin composition. Furthermore, in the present invention, a polymer obtained by adding a crosslinking agent such as divinylbenzene to a styrene monomer may be used.

Examples of the conjugated diene rubbery polymer used for rubber modification of the rubber-modified styrene resin of the present invention include polybutadiene, styrene-butadiene random or block copolymers, polyisoprene, polychloroprene, and styrene-isoprene random. , Block or graft copolymers, ethylene-propylene rubber, ethylene-propylene-diene rubber, and the like, and polybutadiene and styrene-butadiene random, block or graft copolymers are particularly preferable. These may be partially hydrogenated.

The (A) rubber-modified styrene-based resin of the present invention preferably uses a high-cis polybutadiene rubber in which 70% by mass or more of the rubber component contains cis-1,4 bonds in a ratio of 90 mol% or more. It is done. When a low-cis polybutadiene rubber having a 1,4-cis bond content of 10 to 40 mol% is used, it is not preferable because releasability is lowered.

Examples of such (A) rubber-modified styrene resin include impact polystyrene (HIPS), ABS resin (acrylonitrile-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), AES resin (acrylonitrile-ethylenepropylene-styrene copolymer), MBS resin (methyl methacrylate-butadiene-styrene copolymer) and the like can be mentioned.

(B) Brominated flame retardants include brominated phthalimide compounds, brominated diphenylalkane compounds, tris (polybromophenoxy) triazine compounds, ether derivatives of halogen-containing aromatic diols, brominated polystyrene, brominated polyacrylates, brominated Examples include modified products in which a part or all of glycidyl groups at the molecular chain ends of polyphenylene ether and brominated bisphenol A type epoxy resins are sealed, particularly (B-1) brominated phthalimide compounds, (B-2) bromine. Preferably, it is at least one bromine-containing flame retardant selected from a diphenylalkane compound, (B-3) tris (polybromophenoxy) triazine compound, and (B-4) an ether derivative of a halogen-containing aromatic diol.

The (B-1) brominated phthalimide compound used in the present invention is a compound represented by the following (Chemical Formula 1).

（ここで、ＲはＣｎＨ２ｎ（ｎは０〜６の整数）の構造のアルキレン基、Ｘ１およびＸ２はそれぞれ独立に整数１〜４の臭素原子でありＸ１＋Ｘ２≧２を表す。）

(Wherein R is an alkylene group having a structure of CnH2n (n is an integer of 0 to 6), X1 and X2 are each independently a bromine atom of an integer of 1 to 4, and X1 + X2 ≧ 2).

(B-1) Dibromo substitution such as methylene-bis-phthalimide, ethylene-bis-phthalimide, propylene-bis-phthalimide, butylene-bis-phthalimide, pentylene-bis-phthalimide, hexylene-bis-phthalimide as brominated phthalimide compounds , Tribromo-substituted, tetrabromo-substituted, pentabromo-substituted, hexabromo-substituted, heptabromo-substituted, and octabromo-substituted. Preferred are octabromo-substituted products of ethylene-bis-phthalimide, propylene-bis-phthalimide, butylene-bis-phthalimide, pentylene-bis-phthalimide, and hexylene-bis-phthalimide.

The (B-2) brominated diphenylalkane compound used in the present invention is a compound represented by the following (Chemical Formula 2).

（ここで、ＲはＣｎＨ２ｎ（ｎは１〜１０の整数）の構造のアルキレン基、Ｘ１およびＸ２はそれぞれ独立に整数１〜５の臭素原子でありＸ１＋Ｘ２≧２を表す。）

Here, R is an alkylene group having a structure of CnH2n (n is an integer of 1 to 10), X1 and X2 are each independently a bromine atom of an integer of 1 to 5, and X1 + X2 ≧ 2.

(B-2) As brominated diphenylalkane compounds, dibromo-substituted products such as diphenylmethane, 1,2-diphenylethane, 1,3-diphenylpropane, 1,6-diphenylhexane, tribromo-substituted products, tetrabromo-substituted products, and pentabromo-substituted products , Hexabromo substituted, heptabromo substituted, octabromo substituted, nonabromo substituted, decabromo substituted. Preferred are octabromo-substituted, nonabromo-substituted and decabromo-substituted diphenylalkanes, and particularly preferred is decabromodiphenylethane.

The (B-3) tris (polybromophenoxy) triazine compound used in the present invention is a compound represented by the following (Chemical Formula 3).

（ここで、Ｘは独立に整数１〜３の臭素原子でありＸ１＋Ｘ２＋Ｘ３≧３を表す。）

(Here, X is independently a bromine atom having an integer of 1 to 3, which represents X1 + X2 + X3 ≧ 3.)

(B-3) Examples of the tris (polybromophenoxy) triazine compound include tribromo-substituted, tetrabromo-substituted, pentabromo-substituted, hexabromo-substituted, heptabromo-substituted, octabromo-substituted and nonabromo-substituted triphenoxytriazine. Preferred are octabromo-substituted and nonabromo-substituted triphenoxytriazine, and particularly preferred is tris (tribromophenoxy) triazine.

The ether derivative of (B-4) halogen-containing aromatic diol used in the present invention has a softening point in the range of 105 ° C. to 150 ° C. and a molecular weight in the range of 2,000 to 10,000, and is shown below (Chemical Formula 4) It is a compound represented by these.

（ここで、Ｒ１、Ｒ２は水素または（化５）または（化６）から選ばれた同一または異種の基であり、Ｘ１、Ｘ２、Ｘ３およびＸ４はそれぞれ独立に整数１〜４の臭素原子あるいは塩素原子であり、ｎは０を含む自然数である。）

（ここで、Ｒ３は炭素数１〜８のアルキル基または（化７）から選ばれた同一または異種の基である。）

（ここで、Ｙはそれぞれ独立に整数１〜５の臭素原子あるいは塩素原子である。）

(Wherein R1 and R2 are the same or different groups selected from hydrogen or (Chemical Formula 5) or (Chemical Formula 6), and X1, X2, X3 and X4 are each independently a bromine atom having an integer of 1 to 4 or A chlorine atom, and n is a natural number including 0.)

(Here, R3 is the same or different group selected from an alkyl group having 1 to 8 carbon atoms or (Chemical Formula 7).)

(Here, Y is each independently an integer 1 to 5 bromine atom or chlorine atom.)

(B) As for the bromine containing flame retardant, it is essential to use 10-20 mass parts as the addition amount, Preferably it is 12-18 mass parts. (B) If the bromine-containing flame retardant is less than 10 parts by mass, flame retardancy cannot be ensured, and if it is more than 20 parts by mass, the Charpy impact strength decreases.

In the present invention, (B) a flame retardant aid is used together with (B) a bromine-containing flame retardant. The flame retardant aid functions to further enhance the flame retardant effect of the flame retardant, such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, boric acid as a boron compound, etc. Zinc, barium metaborate, anhydrous zinc borate, anhydrous boric acid, etc., tin compounds such as stannic oxide, zinc stannate, zinc hydroxystannate, etc., molybdenum compounds such as molybdenum oxide, ammonium molybdate, zirconium compounds, etc. Zirconium oxide, zirconium hydroxide, etc., and zinc-based compounds include zinc sulfide. Antimony trioxide is preferred.

(C) It is essential to use 1 to 10 parts by mass of the flame retardant aid, and preferably 2 to 8 parts by mass. When the amount of the flame retardant aid is less than 1 part by mass, flame retardancy cannot be ensured, and when it is more than 10 parts by mass, the Charpy impact strength is lowered.

(D) A block copolymer having a Z average molecular weight (Mz) of 200,000 ≦ Mz ≦ 500,000 and comprising styrene and 1,3-butadiene is obtained by polymerizing styrene and 1,3-butadiene. It is a block copolymer characterized by these. When the Z average molecular weight is less than 200,000, the heat resistance is remarkably lowered, and when it exceeds 500,000, the fluidity is remarkably lowered. Preferably, 250,000 ≦ Mz ≦ 400,000.

(D) The block average copolymer having a Z average molecular weight (Mz) of 200,000 ≦ Mz ≦ 500,000 and styrene and 1,3-butadiene has a styrene content of 10 to 50 mass in the copolymer. %. Preferably 10 to 40 mass%. When the styrene content in the copolymer is less than 10% by mass, the effect of improving the heat resistance is poor, and when it exceeds 50% by mass, the impact resistance is remarkably lowered.

(D) Z average molecular weight (Mz) is 200,000 <= Mz <500,000, and the compounding quantity of the block copolymer which consists of styrene and 1, 3- butadiene is 0.5-5 mass parts. (D) When there are few block copolymers than 0.5 mass part, the effect of a fluid improvement will not express. Moreover, when it exceeds 5 mass parts, since heat resistance falls significantly, it is unpreferable. Preferably it is 1-4 mass parts.

(D) The block average copolymer having a Z average molecular weight (Mz) of 200,000 ≦ Mz ≦ 500,000 and styrene and 1,3-butadiene is (a) styrene having an Mw of less than 200,000 and 1 , 3-butadiene block copolymer and / or (b) a block copolymer resin composition of styrene and 1,3-butadiene having a Mw of 200,000 or more.

The mass ratio (A) / (B) is 40 to 90/10 to 60. (I) If the component is less than 40, the fluidity of the resin composition is lowered, and if it exceeds 90, the effect of improving the impact resistance of the resin composition of the present invention is scarce. Preferably it is 50-70 / 30-50.

The resin composition of the present invention includes various additives, for example, dyes and pigments, anti-coloring agents, lubricants, antioxidants, anti-aging agents, light stabilizers, antistatic agents, and fillers, as long as the gist of the present invention is not exceeded. Further, known additives such as compatibilizers, and modifiers such as colorants such as titanium oxide and carbon black can be added. These addition methods are not particularly limited, and are known methods, for example, (A) the rubber-modified styrenic resin to be used, before the start of polymerization, with respect to the reaction solution in the middle of polymerization, after the completion of polymerization, or ( B) a bromine-containing flame retardant, (C) a flame retardant aid, and (D) a block copolymer composed of styrene and 1,3-butadiene having a Z average molecular weight (Mz) of 200,000 ≦ Mz ≦ 500,000. When compounding, it can also be added in an extruder or a molding machine.

A known mixing technique can be applied to the method for mixing the resin composition of the present invention. For example, a uniform styrene-based flame retardant resin composition is obtained by further melt-kneading a mixture preliminarily mixed with a mixing apparatus such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer. I can do it. There is no particular limitation on melt kneading, and a known melting technique can be applied. Suitable melt kneaders include Banbury mixers, kneaders, rolls, single screw extruders, special single screw extruders, and twin screw extruders. Furthermore, there is a method of separately adding an additive such as a flame retardant from the middle of a melt-kneading apparatus such as an extruder.

Although there is no restriction | limiting in particular in the molding method which obtains a molded article from the resin composition of this invention, Preferably they are vacuum molding and injection molding.

Hereinafter, the present invention will be described in detail by reference examples, examples and comparative examples, but the present invention is not limited thereto.

(A) Rubber-modified styrene resin: The rubber-modified styrene resin (A) used in Examples and Comparative Examples has the following composition. This is a rubber-modified styrene resin using a high-cis polybutadiene rubber containing cis 1,4 bonds in a ratio of 90 mol% or more in the rubber-like polymer. The composition of this rubber-modified styrene resin has a reduced viscosity of 0.76 dl / g in the matrix portion, a rubber-like polymer content of 9.1% by mass, and a rubber-like polymer gel content of 26%. The volume average particle diameter of the rubber-like polymer is 2.8 μm. The reduced viscosity, the mass% of the rubber-like polymer, the mass% of the gel content of the rubber-like polymer, and the volume average particle diameter of the rubber-like polymer as measured herein were measured by the following methods.

Measurement of reduced viscosity (ηsp / C): 1 g of rubber-modified styrene resin is mixed with 17.5 ml of methyl ethyl ketone and 17.5 ml of acetone, dissolved by shaking at a temperature of 25 ° C. for 2 hours, and then insoluble by centrifugation. The mixture is allowed to settle, the supernatant is removed by decantation, 250 ml of methanol is added to precipitate the resin component, and the insoluble component is filtered and dried. The resin component obtained by the same operation was dissolved in toluene to prepare a sample solution having a polymer concentration of 0.4% (mass / volume). The sample solution and pure toluene were measured at a constant temperature of 30 ° C. using a Ubbelohde viscometer, and the number of seconds during which the solution flowed was measured.
ηsp / C = (t1 / t0-1) / C
t0: Pure toluene flow down seconds
t1: Sample solution flow down seconds
C: Polymer concentration

Measurement of rubbery polymer content: The styrenic flame retardant resin composition was dissolved in chloroform, a certain amount of iodine monochloride / glacial acetic acid solution was added and left in the dark for about 30 minutes, and then 15% by mass of iodine. Potassium iodide solution and 50 ml of pure water were added, and excess iodine monochloride was titrated with 0.1N sodium thiosulfate solution, and calculated from the amount of iodine monochloride added.

Measurement of gel content: rubber-modified styrene resin was added to toluene at a ratio of 3.3% (mass / volume), dissolved by shaking at a temperature of 25 ° C. for 40 minutes, and then centrifuged (revolution speed: 10,000 to 14000 rpm, separation) The insoluble content (gel content) was allowed to settle at 30 minutes, and the supernatant was removed by decantation to obtain a gel. Next, this swollen gel was preliminarily dried at a temperature of 100 ° C. for 2 hours and then dried for 1 hour by a vacuum dryer at a temperature of 120 ° C. It cooled to normal temperature with the desiccator, weighed precisely, and computed with the following formula.
Gel fraction (%) = [(m1-m0) / S] × 100
m0: centrifugal sedimentation tube mass
m1: Dry gel + centrifugal sedimentation tube mass
S: Sample resin mass

Measurement of volume average particle diameter of rubber-like polymer: A rubber-modified styrene resin was completely dissolved in dimethylformamide and measured with a laser diffraction particle size distribution apparatus.

(B-1) Brominated phthalimide compound: Trade name SAYTEX BT-93 (manufactured by Albemarle Japan) was used.

(B-2) Brominated diphenylalkane compound: Trade name SAYTEX 8010 (manufactured by Albemarle Japan) was used.

(B-3) Tris (polybromophenoxy) triazine compound: trade name SR245 (Daiichi Kogyo Seiyaku Co., Ltd.) was used.

(B-4) Ether derivative of halogen-containing aromatic diol: Trade name EC14 (Dainippon Ink Co., Ltd.) was used.

(C) Flame retardant aid: Antimony trioxide trade name AT-3CN (manufactured by Suzuhiro Chemical Co., Ltd.) was used.

(D) A block average copolymer having a Z average molecular weight (Mz) of 200,000 ≦ Mz ≦ 500,000 and comprising styrene and 1,3-butadiene includes (D-1) styrene and 1,3-butadiene. The product name DX410 (Mz: 360,000, styrene content: 18%, butadiene content 82%, (A) / (B) mass ratio: 62/38) manufactured by Clayton Co., which is a block copolymer of .

For comparison, (D) Z average molecular weight Mz is 200,000 ≦ Mz ≦ 500,000, and instead of a block copolymer composed of styrene and 1,3-butadiene, (D-2) styrene and 1,3- Trade name DX405 (Mz: 120,000, styrene content: 24%, butadiene content: 76%, mass ratio of (a) / (b): 98/2), a product of Clayton, which is a block copolymer of butadiene Was used.

For comparison, (D) Z average molecular weight Mz is 200,000 ≦ Mz ≦ 500,000, and instead of a block copolymer composed of styrene and 1,3-butadiene, (D-3) a block copolymer of styrene and isoprene is used. The product name D1111 (Mz: 210,000, styrene content: 22%, isoprene content 78%, mass ratio of (A) / (B): 64/36) manufactured by Kraton, which is a polymer, was used.

Next, a method for mixing the resin composition of the present invention will be described. (A) rubber-modified styrene resin, (B) bromine-containing flame retardant, (C) flame retardant aid, (D) Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and A block copolymer composed of 1,3-butadiene was blended in the amounts shown in the table, and all these components were premixed with a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Co., Ltd.), and a twin-screw extruder (Toshiba Machine Co., Ltd.). Manufactured, TEM26SS) to form a strand, which was cooled with water and led to a pelletizer to be pelletized. At this time, the cylinder temperature was 200 ° C., and the supply amount was 30 kg / hour. In addition, as for the comparative example, (D) Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and various block copolymers are used in place of the block copolymer composed of styrene and 1,3-butadiene. The same operation was carried out.

Various measurements shown in Examples and Comparative Examples were performed by the following methods.

<Molecular weight>
Number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) were measured under the following conditions using gel permeation chromatography (GPC).
GPC model: Shodex GPC-101 manufactured by Showa Denko KK
Column: Polymer Laboratories PLgel 10 μm MIXED-C
Mobile phase: Chloroform Sample concentration: 0.2% by mass
Temperature: Oven 40 ° C
Detector: Differential refractometer The molecular weight measurement of each component in the present invention is performed by calculating the molecular weight at each elution time from the elution curve of monodisperse polystyrene, and calculating the molecular weight in terms of polystyrene.
Further, (D) Z average molecular weight (Mz) in the present invention is 200,000 ≦ Mz ≦ 500,000, and (A) / (B) mass ratio of a block copolymer comprising styrene and 1,3-butadiene. Was calculated from the integral molecular weight distribution curve of JIS K 7252-2.

<Styrene and butadiene content>
(D) Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and the measurement of the styrene content and the butadiene content of a block copolymer comprising styrene and 1,3-butadiene is JIS K 6231- 2 was performed using a pyrolysis gas chromatograph.

<Specimen creation>
Injection molding machine: J100E-P manufactured by Nippon Steel Works
The obtained pellets were heated and dried at a temperature of 70 ° C. for 3 hours, and then A-type test pieces (dumbbells) described in JIS K 7139 were molded using an injection molding machine.

<Impact resistance>
The impact resistance of the resin composition in the present invention was evaluated by the Charpy impact value.
The Charpy impact value was tested in accordance with JIS K 7111-1, with an edgewise impact, using a 1.0 J weight.
When the strength is less than 10, the strength as a large molded product is insufficient, and the Charpy impact strength is determined to be 10 KJ / m ² or more.

<Heat resistance>
Deflection temperature under load (HDT)
The deflection temperature under load was measured based on JIS K 7191.
Measuring device: No. 148-HD-PC-3 (manufactured by Yasuda Seiki)
Stress: 1.80 MPa
Distance between fulcrums: 64mm
Specimen size: Length 80 mm Width 10 mm Height 4 mm Flat-wise load deflection temperature of less than 69 ° C is insufficient to dissipate heat from large OA equipment and home appliances.

<Fluidity>
Melt flow rate (MFR)
The melt flow rate was measured on the obtained pellets based on JISK7210.
Test temperature: 200 ° C
Test load: 49N
A melt flow rate of 4 or more was considered acceptable.

[Combustion quality]
The test piece for evaluation of combustibility was formed as a 127 × 12.7 × 2.0 mm combustion test piece using an injection molding machine (manufactured by Nippon Steel Works, J100E-P). A combustion test was performed based on the vertical combustion test method (UL94) of Subject 94 of US Underwriters Laboratories. In this test method, the case where the evaluation was 5V required for the large equipment exterior cover was accepted, and the case where it was less than 5V was rejected.

(A) rubber-modified styrene resin, (B) bromine-containing flame retardant, (C) flame retardant aid, (D) Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and The evaluation results are shown in Tables 1 to 4 together with the blending amounts of the block copolymer composed of 1,3-butadiene.

From the examples in Table 1 and Table 2, it can be seen that the resin composition of the present invention is excellent in fluidity, heat resistance, impact resistance and flammability.

From the comparative examples of Tables 3 and 4, a resin composition that does not satisfy the provisions of the present invention is inferior in impact resistance, heat resistance, fluidity, and combustibility.

(D) The Z average molecular weight (Mz) is 200,000 ≦ Mz ≦ 500,000, and the blending amount of the block copolymer composed of styrene and 1,3-butadiene is out of the specified range, or the copolymer weight other than the specified range When a coalescence is used, the effect of increasing both heat resistance and fluidity cannot be obtained. (Comparative Examples 1-4). Further, if the blending amount of (B) bromine-containing flame retardant and (C) flame retardant aid is outside the specified range, the flame retardancy or impact resistance does not satisfy the requirements (Comparative Examples 5 to 8).

Since the resin composition of the present invention is excellent in fluidity and heat resistance, it is advantageous to use it in OA equipment such as large-sized printers and copying machines, and home appliances such as TV and audio.

Claims (2)

(A) 100 parts by mass of the rubber-modified styrene resin, (B) 10 to 20 parts by mass of a bromine-containing flame retardant, (C) 1 to 10 parts by mass of a flame retardant aid, (D) Z average molecular weight ( Mz) is a block copolymer comprising 200,000 ≦ Mz ≦ 500,000 and comprising styrene and 1,3-butadiene , comprising the following components (a) and (b): (B) A styrene-based flame retardant resin composition containing 0.5 to 5 parts by mass of a block copolymer having a mass ratio of components of 40 to 90/10 to 60 .
(A) A block copolymer comprising styrene and 1,3-butadiene having an Mw of less than 200,000
(B) A block copolymer comprising styrene and 1,3-butadiene having an Mw of 200,000 or more. The molded object obtained by shape | molding the resin composition of Claim 1 .

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