Thermoplastic composition and molded article thereof

Abstract

To provide a striking sound reduction material excellent in striking sound reduction performance of an obtained molding, appearance performance and impact resistance.SOLUTION: A striking sound reduction material made of a graft copolymer comprises: a block (I) having a structural unit derived from an aromatic vinyl compound; and a block (II) having a structural unit derived from isoprene or isoprene and butadiene as a main body, in which the block (II) is a graft copolymer that is obtained by graft polymerizing, under the presence of a block copolymer having a peak of main dispersion of tanδ at 0°C or more, a (meth)acrylic acid alkyl ester compound or a graft component made of other vinyl monomer capable of copolymerizing with a (meth)acrylic acid alkyl ester compound and a graft component made of other vinyl monomer capable of copolymerizing with a (meth)acrylic acid alkyl ester compound.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a noise reduction material having excellent noise reduction characteristics and appearance characteristics, a thermoplastic resin composition containing the noise reduction material, and a molded article formed by molding the thermoplastic resin composition.

Background Art

[0002] Rubber-reinforced resins such as ABS resin are widely used as molding materials for vehicle parts such as automotive interior parts due to their excellent mechanical properties, heat resistance, and moldability. Polycarbonate resins, particularly aromatic polycarbonate resins, are also widely used as molding materials for vehicle parts such as automotive interior parts because, in addition to their excellent heat resistance and mechanical properties, they are excellent in impact resistance and dimensional stability.

[0003] When molding vehicle parts with resin, not only must a certain level of mechanical strength be satisfied, but also, due to the relationship of habitability in the vehicle interior, noise reduction characteristics that reduce the noise generated from the parts and improve the quietness of the vehicle are required.

[0004] Conventionally, it has been known that a styrene-isoprene-styrene block copolymer exhibits noise reduction characteristics for thermoplastic resin molded articles, and as this block copolymer, "Hybrar 5127" (trade name, manufactured by Kuraray Co., Ltd.) is commercially available. Further, Patent Documents 1 and 2 describe using, as a noise reduction material to be blended in a thermoplastic resin composition, a graft copolymer obtained by graft-polymerizing a vinyl monomer containing an aromatic vinyl compound to this "Hybrar 5127".

[0005] Note that Patent Documents 1 and 2 state that for vinyl monomers graft-polymerized onto block copolymers such as "Hybrar 5127", an aromatic vinyl compound is an essential component, and preferably an aromatic vinyl compound and a vinyl cyanide compound are used. In these Patent Documents 1 and 2, although examples of (meth)acrylic acid alkyl ester compounds are given as vinyl monomers for graft polymerization, there is no description of specific examples of graft polymerization of (meth)acrylic acid alkyl ester compounds.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] According to the study by the present inventor, although conventional impact noise reduction materials do not cause problems with poor appearance for ABS resin, when compounded with polycarbonate resin, in order to obtain the desired impact noise reduction effect, if the compounding amount is increased, the impact resistance is significantly reduced, and due to the peeling phenomenon, the appearance of the obtained molded product is significantly impaired. Here, the peeling phenomenon refers to the phenomenon in which the surface layer of the molded product peels off in layers, and this phenomenon was particularly prominent around the gate cut portion of injection molded products.

[0008] Also, in the impact noise reduction materials described in Patent Documents 1 and 2, although the peeling phenomenon is suppressed, it has been found that when the addition amount of the impact noise reduction material is increased, the impact resistance is significantly impaired.

[0009] Accordingly, an object of the present invention is to provide a sound reduction material that reduces the peeling phenomenon without impairing the sound reduction effect and mechanical properties of conventional sound reduction materials, and is excellent in the sound reduction characteristics, appearance characteristics, and impact resistance of the resulting molded product, a thermoplastic resin composition containing this sound reduction material, and a molded product thereof.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using an alkyl (meth)acrylate compound as a graft component of the sound reduction material, and has completed the present invention.

[0011] That is, the gist of the present invention is as follows.

[0012] [1] A sound reduction material comprising a graft copolymer obtained by graft-polymerizing a graft component composed of an alkyl (meth)acrylate compound or an alkyl (meth)acrylate compound and another vinyl monomer copolymerizable therewith in the presence of a block copolymer having a block (I) mainly composed of a structural unit derived from an aromatic vinyl compound and a block (II) mainly composed of a structural unit derived from isoprene or isoprene and butadiene, and the block (II) has a peak of the main dispersion of tanδ at 0°C or higher.

[0013] [2] The sound reduction material according to [1], wherein the mass ratio of the block (I) to the block (II) of the graft copolymer is block (I) / block (II) = 10 to 30 / 90 to 70, the content of the block copolymer is 1 to 80% by mass, and the graft ratio is 8 to 35%.

[0014] [3] The sound reduction material according to [1] or [2], wherein the content of the alkyl (meth)acrylate compound in 100% by mass of the graft component is 80 to 100% by mass.

[0015] [4] The sound reduction material according to any one of [1] to [3], wherein the (meth) acrylic acid alkyl ester compound is methyl (meth) acrylate.

[0016] [5] The sound reduction material according to any one of [1] to [4], which is a sound reduction material for a polycarbonate resin or a polycarbonate resin composition.

[0017] [6] A thermoplastic resin composition comprising the sound reduction material according to any one of [1] to [5] and a polycarbonate resin.

[0018] [7] The thermoplastic resin composition according to [6], which contains the polycarbonate resin and a rubber-reinforced styrenic thermoplastic resin and / or a styrenic resin as a resin component other than the sound reduction material (hereinafter referred to as "matrix resin component"), and the content ratio of the polycarbonate resin in 100% by mass of the matrix resin component is 50 to 100% by mass.

[0019] [8] The thermoplastic resin composition according to [6] or [7], wherein the content ratio of the sound reduction material to the total 100 parts by mass of the matrix resin component and the sound reduction material is 10 to 30 parts by mass.

[0020] [9] A molded article comprising the thermoplastic resin composition according to any one of [6] to [8]. [Advantages of the Invention]

[0021] According to the present invention, there is provided a molded article in which the generation of knocking sound is suppressed, without impairing mechanical properties such as impact resistance, and further, a molded article in which a peeling phenomenon is prevented and the appearance properties are excellent can be provided. [Brief Description of the Drawings]

[0022]

Figure 1

[0023] The embodiments of the present invention will be described in detail below.

[0024] In the present invention, “(co)polymerization” means homopolymerization and / or copolymerization, “(meth)acrylic” means acrylic and / or methacrylic, and “(meth)acrylate” means acrylate and / or methacrylate.

[0025] [Impact sound reduction material] The impact sound reduction material of the present invention has a block (I) mainly composed of structural units derived from an aromatic vinyl compound and a block (II) mainly composed of structural units derived from isoprene or isoprene and butadiene, and the block (II) has a peak of the main dispersion of tanδ at 0 °C or higher. In the presence of a block copolymer (hereinafter, may be referred to as “the block copolymer of the present invention”), a graft component composed of an alkyl (meth)acrylate compound or an alkyl (meth)acrylate compound and another vinyl monomer copolymerizable with the alkyl (meth)acrylate compound is graft-polymerized to form a graft copolymer (hereinafter, may be referred to as “the graft copolymer of the present invention”).

[0026] <Block copolymer> Examples of the aromatic vinyl compound constituting the block (I) of the block copolymer of the present invention include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene, etc. These compounds can be used alone or in combination of two or more. Among these, styrene and α-methylstyrene are preferred.

[0027] Block (I) preferably contains 80% by mass or more, more preferably 90 to 100% by mass, of structural units derived from an aromatic vinyl compound. When block (I) contains a structural unit derived from a compound other than an aromatic vinyl compound, examples of the other compound include isoprene and butadiene that constitute block (II) below.

[0028] Block (II) mainly consists of a structural unit derived from isoprene, or a structural unit mainly derived from isoprene and butadiene.

[0029] Block (II) preferably contains 80% by mass or more, more preferably 90 to 100% by mass, of a structural unit derived from isoprene or a structural unit derived from isoprene and butadiene. When block (II) contains a structural unit derived from a compound other than isoprene and butadiene, examples of the other compound include the aromatic vinyl compound that constitutes block (I) described above. The content of 3,4-bonds and 1,2-bonds in block (II) is preferably 40% or more, more preferably 50% or more, and still more preferably 60 to 98%.

[0030] The peak of the main dispersion of tanδ of block (II) needs to be 0 °C or higher, preferably 5 °C or higher, and more preferably 10 °C or higher. The peak of the main dispersion of tanδ can be determined by measuring with a viscoelasticity measuring device [manufactured by Toyo Baldwin Co., Ltd., DDV III EP] at a frequency of 11 Hz, a measurement temperature of -110 °C to +100 °C, and a temperature increase rate of 2 °C / min. The peak of the main dispersion of tanδ of block (II) is particularly preferably 20 to 30 °C.

[0031] The number average molecular weight of block (I) is preferably 2500 to 40000, more preferably 3500 to 35000, and still more preferably 4000 to 30000. The number average molecular weight of block (II) is preferably 10000 to 200000, more preferably 20000 to 180000, and still more preferably 25000 to 150000.

[0032] The total number-average molecular weight of the block copolymer of the present invention is preferably from 30,000 to 300,000, more preferably from 40,000 to 270,000, and even more preferably from 50,000 to 250,000. Here, the number-average molecular weight is the value measured by GPC.

[0033] In the block copolymer of the present invention, the mass ratio of block (I) to block (II) is preferably block (I) / block (II) = 10 to 30 / 90 to 70. If the block (I) / block (II) mass ratio is within the above range, the effect of suppressing the knocking sound is further excellent. The mass ratio of block (I) / block (II) is preferably 10 to 30 / 90 to 70, more preferably 15 to 25 / 85 to 75.

[0034] In the present invention, the content of the block copolymer in the knocking sound reducing material, that is, the rubber content, is preferably 1 to 80% by mass, more preferably 3 to 75% by mass, still more preferably 4 to 70% by mass, particularly preferably 5 to 70% by mass, and especially preferably 7 to 65% by mass, based on 100% by mass of the entire knocking sound reducing material. When the rubber content is within the above range, the impact resistance, the effect of reducing the knocking sound, and the moldability of the thermoplastic resin composition obtained by blending it are more excellent and preferable. In addition, the knocking sound reducing material of the present invention may contain a rubber component other than the block copolymer of the present invention as long as the object of the present invention is not impaired.

[0035] <Graft component> The knocking sound reducing material of the present invention is obtained by graft-polymerizing a graft component containing an alkyl (meth)acrylate compound as an essential component onto the block copolymer of the present invention.

[0036] Specific examples of the (meth)acrylic acid ester compound include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and the like. These compounds can be used alone or in combination of two or more. Among these, methyl (meth)acrylate is preferred, and methyl methacrylate is more preferred.

[0037] The graft component may contain a vinyl monomer copolymerizable with the (meth)acrylic acid alkyl ester compound other than the (meth)acrylic acid alkyl ester compound (hereinafter sometimes referred to as "other vinyl monomer").

[0038] The other vinyl monomer is not particularly limited, and examples thereof include aromatic vinyl compounds, vinyl cyanide compounds, maleimide compounds, unsaturated acid anhydrides, carboxyl group-containing unsaturated compounds, hydroxyl group-containing unsaturated compounds, oxazoline group-containing unsaturated compounds, epoxy group-containing unsaturated compounds, and the like. These can be used alone or in combination of two or more.

[0039] Specific examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyltoluene, vinylxylene, vinylnaphthalene, and the like. Among these, styrene and α-methylstyrene are preferred.

[0040] Specific examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, ethacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, and the like. Among these, acrylonitrile is preferred.

[0041] Examples of the maleimide compound include N-phenylmaleimide, N-cyclohexylmaleimide, and the like.

[0042] Specific examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like.

[0043] Specific examples of the carboxyl group-containing unsaturated compound include (meth)acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, and the like.

[0044] Specific examples of the hydroxyl group-containing unsaturated compound include 3-hydroxy-1-propene, 4-hydroxy-1-butene, cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl-1-propene, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and the like.

[0045] When using other vinyl monomers as the graft component, the content of the alkyl (meth)acrylate compound in 100% by mass of the graft component (total of the alkyl (meth)acrylate compound and other vinyl monomers) is preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass in order to surely obtain the effects of the present invention by using the alkyl (meth)acrylate compound.

[0046] <Graft ratio> The graft ratio of the graft copolymer which is the impact noise reduction material of the present invention is preferably 8 to 35%, more preferably 9 to 26%, and particularly preferably 10 to 20%. It is preferable that the graft ratio of the impact noise reduction material is within the above range from the viewpoint of the impact noise reduction effect.

[0047] Here, the graft ratio can be determined by the following formula (1). Grafting ratio (mass %) = ((S - T) / T) × 100 …(1) In the above formula, S is the mass (g) of the insoluble matter obtained by adding 1 g of the graft copolymer, which is the sound reduction material, to 20 mL of acetone, shaking it for 2 hours with a shaker under the temperature condition of 25°C, and then centrifuging it for 60 minutes with a centrifuge (rotation speed: 23,000 rpm) under the temperature condition of 5°C to separate the insoluble matter and the soluble matter. T is the mass (g) of the block copolymer of the present invention, which is the rubbery part contained in 1 g of the sound reduction material. The mass of this block copolymer can be determined by infrared spectroscopic analysis, pyrolysis gas chromatography, CHN elemental analysis, etc., in addition to the method of calculating from the polymerization formulation and the polymerization conversion rate.

[0048] The grafting ratio can be adjusted by appropriately selecting, for example, the type and amount of the chain transfer agent used in the graft polymerization when producing the sound reduction material, the type and amount of the polymerization initiator, the addition method and addition time of the monomer component during polymerization, the polymerization temperature, etc.

[0049] <Method for manufacturing sound reduction material> The sound reduction material of the present invention can be produced by graft polymerizing a vinyl monomer containing an alkyl (meth)acrylate compound in the presence of the block copolymer of the present invention. The block copolymer can be produced according to a conventional method. Also, a corresponding commercially available product may be used as the block copolymer.

[0050] The polymerization method in the method for manufacturing the sound reduction material of the present invention is not particularly limited as long as the graft copolymer of the present invention can be obtained, and a known method can be applied. The polymerization method can be emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or a polymerization method combining these. In these polymerization methods, a known polymerization initiator, chain transfer agent (molecular weight regulator), emulsifier, etc. can be appropriately used. Among these polymerization methods, it is preferable to use the emulsion polymerization method from the viewpoint of suppressing VOC.

[0051] As a method for producing the graft copolymer of the present invention by emulsion polymerization, for example, a redox initiator is mixed with a vinyl monomer containing an alkyl (meth)acrylate compound as a graft component, and then this vinyl monomer mixture is continuously added to the aqueous dispersion of the block copolymer of the present invention over 1 hour or more. Emulsion polymerization can be mentioned. When the addition time of the vinyl monomer is less than 1 hour, the graft ratio tends to decrease. In addition, a chain transfer agent, an emulsifier, etc. may be used according to the situation during polymerization. In addition, an antioxidant may be added to the obtained graft copolymer as necessary.

[0052] As the redox initiator, a combination of an oil-soluble organic peroxide and ferrous sulfate - chelating agent - reducing agent is preferable. Examples of the oil-soluble organic peroxide include cumene hydroperoxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, etc. A more preferable redox initiator is composed of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate, and dextrose.

[0053] Examples of the chain transfer agent include mercaptans (octyl mercaptan, n-, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-, t-tetradecyl mercaptan, etc.), allyl sulfonic acid, methallyl sulfonic acid, and allyl compounds such as their soda salts, α-methylstyrene dimer, etc. Among these, mercaptans are preferable. Also, these chain transfer agents may be used alone or in combination of two or more. The addition method of the chain transfer agent may be any of batch, divided, and continuous. In addition, the addition amount of the chain transfer agent is preferably 2.0 parts by mass or less with respect to 100 parts by mass of the vinyl monomer of the graft component.

[0054] Examples of the emulsifier include anionic surfactants, nonionic surfactants, amphoteric surfactants, etc. Examples of anionic surfactants include sulfates of higher alcohols, alkylbenzene sulfonates, fatty acid sulfonates, phosphate salts, fatty acid salts, amino acid derivative salts, and the like. Examples of nonionic surfactants include normal alkyl ester type, alkyl ether type, alkyl phenyl ether type, etc. of polyethylene glycol. Examples of amphoteric surfactants include those having a carboxylate, sulfate ester salt, sulfonate, phosphate ester salt, etc. in the anionic part and an amine salt, quaternary ammonium salt, etc. in the cationic part. The addition amount of the emulsifier is preferably 10 parts by mass or less with respect to 100 parts by mass of the vinyl monomer of the graft component.

[0055] The graft copolymer thus obtained is in a state of being dispersed in water. As a method for recovering the graft copolymer from the aqueous dispersion containing the graft copolymer, for example, a precipitation method can be mentioned in which a precipitant is added to the aqueous dispersion, heated and stirred, and then the precipitant is separated, washed with water, dehydrated, and dried. Examples of the precipitant in the precipitation method include aqueous solutions of sulfuric acid, acetic acid, calcium chloride, magnesium sulfate, etc. These may be used alone or in combination of two or more.

[0056] <Use> As described above, since the problem of appearance deterioration due to the peeling phenomenon is a problem that occurs when a conventional sound reduction material is blended with a polycarbonate resin or a polycarbonate resin composition, the sound reduction material of the present invention is particularly useful as a sound reduction material for a polycarbonate resin or a polycarbonate resin composition.

[0057] [Thermoplastic resin composition] The thermoplastic resin composition of the present invention is characterized by containing the sound reduction material of the present invention and a polycarbonate resin.

[0058] [Polycarbonate resin] As the polycarbonate resin, an aromatic polycarbonate resin is preferred because of its excellent impact resistance.

[0059] Aromatic polycarbonate resins include those obtained by known polymerization methods such as the interfacial polycondensation method of a dihydroxyaryl compound and phosgene, and the transesterification reaction (melt polycondensation) of a dihydroxyaryl compound and a carbonate compound such as diphenyl carbonate. All of them can be used.

[0060] Examples of the dihydroxyaryl compound include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 2,2-bis(4-hydroxy-3-t-butylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxyphenyl ether, 4,4'-dihydroxyphenyl sulfide, 4,4'-dihydroxyphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, hydroquinone, resorcinol, etc. Further, there are polyorganosiloxanes terminated with hydroxyaryloxy (see, for example, U.S. Patent No. 3,419,634). These can be used alone or in combination of two or more. Among these, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is preferred.

[0061] The viscosity-average molecular weight of the aromatic polycarbonate resin is preferably 12,000 to 40,000, more preferably 15,000 to 35,000, and particularly preferably 18,000 to 30,000. A higher molecular weight results in higher mechanical strength of the molded product, but the appearance of the molded product tends to deteriorate due to a decrease in fluidity. Two or more aromatic polycarbonate resins having different molecular weights can also be used as the aromatic polycarbonate resin (A3).

[0062] Here, the viscosity-average molecular weight of the aromatic polycarbonate resin can usually be calculated by inserting the specific viscosity (ηsp) measured at 20 °C and a concentration of [0.7 g / 100 ml (methylene chloride)] using methylene chloride as a solvent into the following formula (2). Viscosity-average molecular weight = ([η] × 8130) 1.205 …(2) Here, [η] = ([(ηsp × 1.12 + 1) 1 / 2 −1]) / 0.56C, and C represents the concentration.

[0063] <Matrix resin component> The thermoplastic resin composition of the present invention may contain only a polycarbonate resin as a matrix resin component other than the sound reduction material of the present invention, or may contain a thermoplastic resin other than the polycarbonate resin. Examples of other thermoplastic resins other than the polycarbonate resin include rubber-reinforced styrene-based thermoplastic resins, styrene-based resins, polyolefin-based resins, vinyl chloride-based resins, acrylic-based resins, polyester-based resins, polyamide-based resins, polyacetal-based resins, polyphenylene ether-based resins, polyarylene sulfide-based resins, and the like. These thermoplastic resins can be used alone or in combination of two or more.

[0064] As other thermoplastic resins to be mixed with the polycarbonate resin, rubber-reinforced styrene-based thermoplastic resins such as ABS resin and AES resin and / or styrene-based resins such as AS resin are particularly preferable from the viewpoint of impact resistance.

[0065] When the thermoplastic resin composition of the present invention contains, as matrix resin components other than the impact sound reducing material, other thermoplastic resins such as rubber-reinforced styrenic thermoplastic resins such as ABS resin and AES resin, and styrenic resins such as AS resin together with a polycarbonate resin, from the viewpoint of more effectively obtaining the effect of preventing peeling by the impact sound reducing material of the present invention, the content rate of the polycarbonate resin in 100% by mass of the matrix resin components other than the impact sound reducing material is preferably 50% by mass or more, particularly preferably 60% by mass or more.

[0066] When the matrix resin component contains an aromatic polycarbonate resin, an ABS resin and / or an AES resin, and an AS resin, the content rate of each resin in 100% by mass of the matrix resin component is preferably 50 to 90% by mass for the aromatic polycarbonate resin, 5 to 30% by mass for the ABS resin and / or the AES resin, and 0 to 30% by mass for the AS resin because the impact resistance is further excellent.

[0067] <Content ratio of the impact sound reducing material> In the thermoplastic resin composition of the present invention, the content ratio of the impact sound reducing material is preferably 5 to 40 parts by mass, particularly 8 to 33 parts by mass, with respect to 100 parts by mass in total of the matrix resin component containing the polycarbonate resin and the impact sound reducing material of the present invention. If the content ratio of the impact sound reducing material is not less than the above lower limit, the impact sound reducing effect by blending the impact sound reducing material can be sufficiently obtained. If the content ratio of the impact sound reducing material is not more than the above upper limit, problems such as a decrease in impact resistance and flexural modulus due to blending a large amount of the impact sound reducing material can be suppressed.

[0068] <Other components> The thermoplastic resin composition of the present invention may contain other components other than the impact sound reducing material and the matrix resin component of the present invention as long as the object of the present invention is not impaired.

[0069] (Sliding property imparting agent) The thermoplastic resin composition of the present invention may contain a slidability-imparting agent. The slidability-imparting agent not only imparts slidability to the thermoplastic resin composition and facilitates the assembly of an article made of a molded product obtained from the thermoplastic resin composition of the present invention, but also can impart an effect of suppressing the generation of abnormal noises such as squeaking sounds from the article made of the molded product during use.

[0070] Typical examples of the slidability-imparting agent include low molecular weight polyethylene oxide, ultra-high molecular weight polyethylene, polytetrafluoroethylene, low molecular weight (for example, number average molecular weight of 10,000 or less) polyolefin wax, silicone oil, etc. as described in JP-A-2011-137066.

[0071] When the slidability-imparting agent is blended with the thermoplastic resin composition of the present invention, the blending amount is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total of the matrix resin component and the sound reduction material of the present invention.

[0072] (Thermal aging inhibitor) In order to suppress the generation of squeaking sounds and obtain a molded product with high surface gloss, a thermal aging inhibitor can be added to the thermoplastic resin composition of the present invention. The thermal aging inhibitor is not particularly limited as long as it is a thermal aging inhibitor blended in rubber or the like, but phenolic antioxidants and phosphorus antioxidants are preferred.

[0073] Examples of the phenolic antioxidant include phenolic antioxidants having a phenolic group with a t-butyl group at the ortho position as represented by the following general formula (I).

[0074] [Chemical formula] TIFF0007711407000002.tif6140

[0075] (In the formula, R 1 and R 2Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and t-Bu represents a t-butyl group.)

[0076] In the general formula (I) above, the substituent R 1 and R 2 are each independently preferably a hydrogen atom, a t-butyl group or a methyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably, the case where R 1 is a hydrogen atom. Specifically, the phenolic antioxidant used in the present invention is preferably a compound having one or more groups represented by the general formula (I), and more preferably a compound represented by any one of the following formulas (C1), (C2) and (C3).

[0077] [Chemical formula] TIFF0007711407000004.tif7140

[0078] Examples of the phosphorus-based antioxidant include compounds represented by the following general formula (II).

[0079] [Chemical formula]

[0080] (In the formula, R 3 and R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Particularly preferably, R 3 and R 4 are t-C4H9 groups.)

[0081] When a heat aging inhibitor is blended into the thermoplastic resin composition of the present invention, the blending amount is preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, still more preferably 0.03 to 2 parts by mass, particularly preferably 0.03 to 1 part by mass, and most preferably in the range of 0.02 to 0.6 parts by mass, 0.02 to 0.2 parts by mass, 0.03 to 0.6 parts by mass, or 0.03 to 0.2 parts by mass, when the thermoplastic resin composition of the present invention is 100 parts by mass. When the blending amount of the heat aging inhibitor is within the above range, the molded product has excellent gloss and a good appearance can be obtained.

[0082] (Other additives) Other additives that can be blended into the thermoplastic resin composition of the present invention include antioxidants, ultraviolet absorbers, weathering agents, fillers, antistatic agents, flame retardants, antifogging agents, lubricants, antibacterial agents, fungicides, tackifiers, plasticizers, colorants, graphite, carbon black, carbon nanotubes, pigments (including pigments imparting functions such as infrared absorption and reflection ability).) etc. These may be used alone or in combination of two or more. The blending amount of these other additives is usually 0.1 to 30 parts by mass with respect to a total of 100 parts by mass of the matrix resin component and the sound reduction material of the present invention.

[0083] <Manufacturing method of thermoplastic resin composition> The thermoplastic resin composition of the present invention can be produced by mixing each component at a predetermined blending ratio using a tumbler mixer, Henschel mixer, etc., and then melt-kneading under appropriate conditions using a kneader such as a single-screw extruder, twin-screw extruder, Banbury mixer, kneader, roll, feeder extruder, etc. A preferred kneader is a twin-screw extruder. Further, when kneading each component, they may be kneaded together, or kneaded in multiple stages or divided blending. In addition, after kneading with a Banbury mixer, kneader, etc., it can also be pelletized by an extruder. The melt-kneading temperature is usually 220 to 280°C, preferably 240 to 260°C.

[0084] [Preferred physical properties, etc.] The suitable physical properties and the like of the thermoplastic resin composition of the present invention will be described below. The physical properties and the like of the thermoplastic resin composition of the present invention described below are specifically measured by the method described in the Examples section shown later.

[0085] <Maximum value of sound pressure> From the viewpoint of suppressing knocking sound, it is preferable that the maximum value of the sound pressure in the frequency range of 20 to 20,000 Hz is 75 dB or less when measured under the following condition (1) for the thermoplastic resin composition of the present invention. Further, the frequency giving this maximum sound pressure value is preferably 3,000 Hz or less, and more preferably 2,000 Hz or less. It is considered that the intensity of the knocking sound is suppressed as the maximum value of the sound pressure shifts to the lower frequency side within the above range. <Measurement condition (1)> Measurement was performed based on the frequency spectrum of the sound pressure obtained by collecting the sound when a test piece, which is an integrally molded product having a trapezoidal protrusion with an upper base of 20 mm, a lower base of 40 mm, a height of 8 mm, and a thickness of 1.5 mm at the center of the upper end side of a rectangular body with a length of 120 mm, a width of 60 mm, and a thickness of 3 mm, obtained by molding the thermoplastic resin composition using an injection molding machine, was suspended with two threads attached to the protrusion with tape, and the center of one surface of the test piece was struck with a stainless steel hammer with a force of 40 ± 5 N, and the sound was collected by a sound pressure microphone installed 12 cm away in a direction perpendicular to the surface.

[0086] <Mechanical properties and heat resistance> The thermoplastic resin composition of the present invention preferably maintains high mechanical strength. For the thermoplastic resin composition of the present invention, the flexural modulus is preferably 1,600 MPa or more, the heat distortion temperature (1.8 MPa) is preferably 70 °C or more, the Rockwell hardness is preferably 90 or more, the tensile strength is preferably 35 MPa or more, the flexural strength is preferably 45 MPa or more, and the Charpy impact strength is preferably 30 kJ / m 2 or more.

[0087] [Molded product] The molded article of the present invention can be manufactured by molding the thermoplastic resin composition of the present invention by known molding methods such as injection molding, gas injection molding, press molding, sheet extrusion molding, vacuum molding, profile extrusion molding, foam molding, material extrusion deposition method, powder sintering laminated manufacturing, etc.

[0088] The molded article of the present invention formed by molding the thermoplastic resin composition of the present invention can be used for vehicle interior parts and exterior parts, particularly because of its excellent impact sound reduction characteristics and appearance characteristics. For example, seat belt buckles, upper boxes, cup holders, door trims, door knobs, door pockets, door linings, pillar garnishes, consoles, console boxes, rearview mirrors, sun visors, center panels, ventilators, air conditioners, air conditioner panels, heater panels, plate-shaped blades, valve shutters, louvers, etc., ducts, meter panels, meter cases, meter visors, instrument panel upper garnishes, instrument panel lower garnishes, A / TIndicators, "on-off switches (slide parts, slide plates), switch bezels, grille front defrosters, grille side defrosters, lid clusters, masks such as cover storers (mask switches, mask radios, etc.), pockets (pocket decks, pocket cards, etc.), steering wheel horn pads, cup holders, switch parts, switch boxes, grips such as assist grips, handles, grab handles, exterior parts for car navigation, camera covers, camera monitoring systems, head-up displays, rear entertainment systems, glove boxes, glove box latches, small-item containers, latches on lids of small-item containers, room mirrors, room lamps, armrests, speaker grilles, navigation panels, overhead consoles, clock indicators, SOS switches, etc. for vehicle interior parts, front grilles, wheel caps, bumpers, fenders, spoilers, garnishes, door mirrors, radiator grilles, rear combination lamps, headlamps, turn lamps, grips of outside door handles, etc. for vehicle exterior parts, office equipment, exterior parts such as cases and housings for household appliances, interior parts, parts around switches, parts of movable parts, lock parts for desks, desk drawers, paper trays for copiers, straight-tube LED lamps, bulb-type LED lamps, bulb-type fluorescent lamps, panels, covers, connectors, etc. for ceiling lights, mobile phones, tablet terminals, rice cookers, refrigerators, microwave ovens, gas stoves, vacuum cleaners, dishwashers, air purifiers, air conditioners, heaters, TVs, recorders, etc. for household appliances, printers, FAX machines, copiers, personal computers, projectors, etc. for OA equipment, audio equipment, organs, electronic pianos, etc. for acoustic equipment, caps for cosmetic containers, battery cell casings, etc., and can be preferably used as vehicle interior parts.

[0089] The molded article of the present invention may be composed of one part or two or more parts, but preferably includes at least two parts that may come into contact with each other, and can be suitably used as parts of an article that may generate a hitting sound when the two parts come into contact with each other. According to the present invention, for example, an article can be provided that includes at least two parts that may come into contact with each other, and at least a part of the part of the other part that may come into contact with at least one of the two parts is formed of the thermoplastic resin composition of the present invention. In other words, according to the present invention, an article can be provided that includes at least a first part and a second part that may come into contact with each other, and at least a part of the part of the first part that may come into contact with the second part is formed of the thermoplastic resin composition of the present invention. In this case, it is preferable that the whole of the first part or a part or all of the part that comes into contact with the second part is formed of the thermoplastic resin composition of the present invention.

[0090] Note that the second part that comes into contact with the first part may be a part molded from the thermoplastic resin composition of the present invention, or may be a part molded from a resin other than the thermoplastic resin composition of the present invention or a part made of another material such as metal.

[0091] Examples of resins other than the thermoplastic resin composition of the present invention include polypropylene-based resins, rubber-reinforced aromatic vinyl-based resins such as ABS resins, acrylic resins such as polymethyl methacrylate, polycarbonate resins, polycarbonate / ABS alloys, nylon resins, nylon / ABS alloys, PET resins, PET / ABS alloys, PBT / ABS alloys, thermoplastic elastomers, and thermosetting elastomers.

[0092] Examples of the article that includes at least a first component and a second component that may come into contact with each other are not particularly limited as long as the first and second components may come into contact with each other as described above. For example, the first and second components are adjacent to each other with a gap therebetween but intermittently come into contact with each other due to an external force such as vibration or an opening / closing operation. More specifically, an article in which both components are loosely fitted, i.e., loosely engaged with each other, can be mentioned. The fitting method of both components is not particularly limited as long as both components are loosely fitted. For example, it may be a snap fit, a screw fit, or an engagement. Examples of such an article include an article provided with an opening / closing part (e.g., a lid, a door) configured to be push-open using a push latch or a magnet latch. More specifically, in vehicle interior parts, opening / closing parts such as a sunglass tray can be mentioned.

Example

[0093] Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited only to the following examples. In the following, "parts" and "%" are based on mass unless otherwise specified.

[0094] 〔Raw materials〕 In the following examples and comparative examples, for the production of the thermoplastic resin composition, the raw materials used were resin components produced by the following methods and the following commercially available products.

[0095] [Rubber-reinforced styrene-based thermoplastic resin] <Production of ABS resin> Into a polymerization vessel equipped with a stirrer, 280 parts of water and 60 parts (in terms of solid content) of a polybutadiene latex having a weight average particle diameter of 0.26 μm and a gel fraction of 90% as a diene rubbery polymer, 0.3 part of sodium formaldehyde sulfoxylate, 0.0025 part of ferrous sulfate, and 0.01 part of disodium ethylenediaminetetraacetate were charged. After deoxidation, the mixture was heated to 60 °C while stirring in a nitrogen stream. Then, a monomer mixture consisting of 10 parts of acrylonitrile, 30 parts of styrene, 0.2 part of t-dodecyl mercaptan, and 0.3 part of cumene hydroperoxide was continuously added dropwise at 60 °C over 5 hours. After the completion of the dropwise addition, the polymerization temperature was raised to 65 °C, and stirring was continued for 1 hour. Then, the polymerization was terminated to obtain a latex of the graft copolymer. The polymerization conversion rate was 98%. Thereafter, 0.2 part of 2,2'-methylene-bis(4-ethyl-6-t-butylphenol) was added to the obtained latex, calcium chloride was added for coagulation, and after passing through the washing, filtration, and drying steps, a powdery ABS resin was obtained. The graft ratio of the obtained ABS resin was 40%, and the limiting viscosity [η] of the acetone-soluble component was 0.38 dl / g.

[0096] <Production of AES resin> Into a 20 L stainless steel autoclave equipped with a ribbon-type stirrer blade, an auxiliary agent continuous addition device, a thermometer, etc., as an ethylene·α-olefin rubbery polymer, an ethylene·propylene copolymer (ethylene / propylene = 78 / 22 (%)) and Mooney viscosity (ML 1+4, 100 °C) 20. The melting point (Tm) is 40 °C, the glass transition temperature (Tg) is -50 °C) 22 parts, 55 parts of styrene, 23 parts of acrylonitrile, 0.5 part of t-dodecyl mercaptan, and 110 parts of toluene were charged. The internal temperature was raised to 75 °C, and the contents of the autoclave were stirred for 1 hour to obtain a homogeneous solution. Then, 0.45 part of t-butyl peroxyisopropyl monocarbonate was added, and the internal temperature was further raised. After reaching 100 °C, the polymerization reaction was carried out at a stirring rotation speed of 100 rpm while maintaining this temperature. From the 4th hour after the start of the polymerization reaction, the internal temperature was raised to 120 °C, and the reaction was further carried out for 2 hours while maintaining this temperature to complete the polymerization reaction. Then, the internal temperature was cooled to 100 °C, 0.2 part of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenol)-propionate and 0.02 part of dimethyl silicone oil; KF-96-100 cSt (trade name: manufactured by Shin-Etsu Silicone Co., Ltd.) were added. After that, the reaction mixture was taken out from the autoclave, and the unreacted substances and the solvent were distilled off by steam distillation. Furthermore, the volatile components were substantially degassed using a 40 mmφ extruder with a vent (cylinder temperature 220 °C, vacuum degree 760 mmHg) and pelletized. The graft ratio of the obtained AES resin was 70%, and the limiting viscosity [η] of the acetone-soluble component was 0.47 dl / g.

[0097] [Styrene resin] <AS resin> As the AS resin, an acrylonitrile-styrene copolymer in which the ratios of acrylonitrile units and styrene units are 24% and 76% respectively, and the weight average molecular weight is 88,000 was used.

[0098] [Polycarbonate resin] <PC resin> As the PC resin, an aromatic polycarbonate resin "NOVAREX 7022J (trade name)" (viscosity average molecular weight 20900) manufactured by Mitsubishi Engineering Plastics Corporation was used.

[0099] [Sound reduction material] <Manufacture of the sound reduction material (MMA)-1 of the present invention> As the block copolymer, styrene-isoprene-styrene (SIS) block copolymer "Hybrar 5127" (trade name, manufactured by Kuraray Co., Ltd., styrene content 20%, glass transition temperature (Tg) 8 °C, peak temperature of the main dispersion of tanδ 25 °C, 3,4 bond and 1,2 bond content 95%) was prepared and made into an aqueous dispersion with a solid content concentration of 30%. Into a stainless steel polymerization tank equipped with a stirrer, 225 parts of ion-exchanged water, 50 parts of the aqueous dispersion of Hybrar 5127 as a solid content, 0.008 part of ferrous sulfate, 0.2 part of sodium pyrophosphate, and 0.47 part of dextrose were charged, and the temperature was set to 80 °C. Next, 50 parts of methyl methacrylate and 0.8 part of t-butyl hydroperoxide were continuously added over 150 minutes, and the polymerization temperature was kept constant at 80 °C to carry out emulsion polymerization. After polymerization, an antioxidant was added to the aqueous dispersion containing the obtained graft copolymer, and precipitation of the solid content was carried out with sulfuric acid. Through the steps of washing, dehydration, and drying, a powdery graft copolymer was obtained. The graft ratio of the obtained graft copolymer was 12%, and the limiting viscosity [η] of the acetone-soluble component was 0.56 dl / g. The sound reduction material made of this graft copolymer is referred to as "Sound Reduction Material (MMA)-1".

[0100] <Production of Sound Reduction Material (MMA)-2 of the Present Invention> In the production of Sound Reduction Material (MMA)-1, Sound Reduction Material (MMA)-2 was obtained in the same manner except that the solid content of the aqueous dispersion of Hybrar 5127 was 60 parts and methyl methacrylate was 40 parts. The graft ratio of the obtained graft copolymer was 19%, and the limiting viscosity [η] of the acetone-soluble component was 0.56 dl / g.

[0101] <Production of Sound Reduction Material (MMA)-3 of the Present Invention> In the production of Sound Reduction Material (MMA)-1, Sound Reduction Material (MMA)-3 was obtained in the same manner except that the solid content of the aqueous dispersion of Hybrar 5127 was 70 parts and methyl methacrylate was 30 parts. The graft ratio of the obtained graft copolymer was 24%, and the limiting viscosity [η] of the acetone-soluble component was 0.56 dl / g.

[0102] <Manufacture of Sound Reduction Material (MMA)-4 of the Present Invention> In the manufacture of the sound reduction material (MMA)-1, the sound reduction material (MMA)-4 was obtained in the same manner except that the solid content of the aqueous dispersion of Hybrar 5127 was 80 parts and methyl methacrylate was 20 parts. The graft ratio of the obtained graft copolymer was 24%, and the intrinsic viscosity [η] of the acetone-soluble component was 0.56 dl / g.

[0103] <Comparative Sound Reduction Material> The above-mentioned "Hybrar 5127" was used as a comparative sound reduction material. This sound reduction material is referred to as "sound reduction material (0)".

[0104] <Manufacture of Comparative Sound Reduction Material> In the manufacture of the sound reduction material MMA, a comparative sound reduction material was obtained in the same manner except that 30 parts of styrene and 10 parts of acrylonitrile were used instead of 40 parts of methyl methacrylate, and t-butyl hydroperoxide was used as cumene hydroperoxide. This sound reduction material is referred to as "sound reduction material (AS)".

[0105] [Experimental Example] An experiment was conducted to examine the presence or absence of peeling by blending the sound reduction material (0) using PC resin and ABS resin, respectively. To 100 parts of PC resin or ABS resin, the sound reduction material (0) was added at the ratios shown in Table 1, and melt-kneaded at 250 °C using a twin-screw extruder (model name "TEX28V, Japan Steel Works") and pelletized. Using the pellets of the obtained resin composition, injection molding was performed at a cylinder temperature of 250 °C, an injection pressure of 50 MPa, and a mold temperature of 80 °C using an IS-170FA injection molding machine manufactured by Toshiba Machine, and a molded plate of 100 mm × 100 mm × thickness 3 mm was obtained. The gate cut portion of this molded plate was visually observed to examine the presence or absence of peeling. The results are shown in Table 1. In addition, in Table 1, the physical property values measured in the same manner as in the examples described later are also shown.

[0106]

Table 1

[0107] It can be seen from Table 1 below that The sound reduction characteristics of both the PC resin and the ABS resin improve in proportion to the addition of the sound reduction material (0). In the case of the ABS resin, peeling does not occur even when up to 13 parts of the sound reduction material (0) are added, but in the case of the PC resin, peeling occurs when 13 parts are added. From this, it can be seen that when a conventional sound reduction material is blended with the PC resin, the appearance of the molded product is impaired by the peeling phenomenon at the addition amount where a sufficient sound reduction effect can be obtained.

[0108] 〔Example 1, Comparative Examples 1 to 6〕 [Manufacture of Thermoplastic Resin Composition] The resin components and the sound reduction material shown in Table 2 were used at the compounding ratios shown in Table 2. Further, the following additives were added and mixed at the following ratios with respect to a total of 100 parts of these resin components. Phosphorus-based antioxidant: Tris(2,4-di-tert-butylphenyl) phosphite manufactured by Johoku Chemical Industry Co., Ltd. Addition amount: 0.2 part Phenolic antioxidant: 2-[1-(2-Hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate manufactured by Sumitomo Chemical Co., Ltd. Addition amount: 0.2 part Carbon black Addition amount: 0.4 part

[0109] This mixture was melt-kneaded at 250 °C using a twin-screw extruder (model name "TEX28V, Nippon Steel Works") and pelletized. Using the obtained resin composition, the following measurements and evaluations were carried out. The results are shown in Table 2 below. In Table 2, the addition amounts of the sound reduction material (MMA) and the sound reduction material (AS) are the numerical values as the addition amount of Hybrar 5127 in these sound reduction materials.

[0110] [Evaluation Method] <Flexural modulus of elasticity> Measured according to ISO178.

[0111] <Flexural strength> Measured in accordance with ISO178.

[0112] <Tensile strength> Measured in accordance with ISO527.

[0113] <Elongation> Measured in accordance with ISO527.

[0114] <Rockwell hardness> Measured in accordance with ISO2039.

[0115] <Heat distortion temperature> Measured in accordance with ISO75 under a load condition of 1.8 MPa.

[0116] <Charpy impact strength> In accordance with ISO179, a Charpy impact test (notched) was conducted at 23 °C to measure the Charpy impact strength.

[0117] <Presence or absence of peeling> The presence or absence of peeling was confirmed in the same manner as in Experimental Example 1.

[0118] <Sound pressure of tapping sound> Using each thermoplastic resin composition, a test piece, which is an integrally molded product having a trapezoidal protrusion with an upper base of 20 mm, a lower base of 40 mm, a height of 8 mm, and a thickness of 1.5 mm at the center of the upper edge of a rectangular body with a length of 120 mm, a width of 60 mm, and a thickness of 3 mm as shown in Fig. 1, was injection molded by a Toshiba Machine IS-170FA injection molding machine at a cylinder temperature of 250 °C, an injection pressure of 50 MPa, and a mold temperature of 60 °C. Then, with two threads attached to the protrusion of this test piece with tape and suspended, the center of one surface of the test piece was struck with a force of 40 ± 5 N using a stainless steel hammer (product name: 086C03) manufactured by PCB Piezotronics, Inc. that can measure the impact force. The sound produced was collected by a sound pressure microphone (product name: 378B02) manufactured by PCB Piezotronics, Inc. installed 12 cm away from the surface in a direction perpendicular to the surface, and converted into a frequency spectrum of sound pressure using a Fourier transform analyzer (product name: Multi JOB FFT Analyzer OR34J-4) manufactured by Oros Co., Ltd. The maximum value of the sound pressure level (dB) and its frequency (Hz) in the obtained frequency spectrum were used as the measured values. The measurement was carried out in a room at room temperature of 23 °C. The sound pressure level (dB) obtained as the measured value means the sound pressure per 1 N of the observed impact force.

[0119] <Attenuation of the impact sound> The same operation as the sound pressure measurement of the impact sound was performed, and the time change of the sound pressure was measured using a Fourier transform analyzer (product name: Multi JOB FFT Analyzer OR34J-4) manufactured by Oros Co., Ltd. The time required for the sound pressure to decay from the generation of the sound to a sound pressure of 1 / 4 of the maximum sound pressure was used as the attenuation time of the impact sound. The attenuation of the impact sound is preferably shorter than 0.01 s, and more preferably shorter than 0.008 s.

[0120]

Table 2

[0121] From Table 2, it can be seen that by using the impact sound reduction material (MMA) of the present invention, even at an addition amount where the impact sound reduction effect can be sufficiently obtained, the decrease in impact resistance can be suppressed, and a molded product with excellent appearance can be obtained without causing a peeling phenomenon. On the other hand, in the case of the impact sound reduction material (0), a peeling phenomenon is observed when 9 parts are added. At an addition amount where the peeling phenomenon does not occur, a sufficient impact sound reduction effect cannot be obtained. Moreover, when the addition amount is increased, the impact resistance is greatly impaired (Comparative Example 4). The impact sound reduction material (AS) corresponds to the impact sound reduction materials described in Patent Documents 1 and 2. Although no peeling phenomenon is observed with this impact sound reduction material (AS), the impact resistance is greatly impaired (Comparative Example 6).

Claims

1. A thermoplastic resin composition comprising a sound reduction material and a resin component other than the sound reduction material (hereinafter referred to as "matrix resin component"), wherein the sound reduction material has a block (I) mainly composed of structural units derived from an aromatic vinyl compound and a block (II) mainly composed of structural units derived from isoprene or isoprene and butadiene, and the block (II) is in the presence of a block copolymer having a peak of the main dispersion of tanδ at 0 °C or higher, and is a sound reduction material composed of a graft copolymer obtained by graft-polymerizing a graft component containing 80% by mass or more of methyl methacrylate, wherein the matrix resin component contains a polycarbonate resin, or a polycarbonate resin and a rubber-reinforced styrene-based thermoplastic resin and / or a styrene-based resin, and the content rate of the polycarbonate resin in 100% by mass of the matrix resin component is 50 to 100% by mass.

2. The thermoplastic resin composition according to Claim 1, wherein the content ratio of the sound reduction material to a total of 100 parts by mass of the matrix resin component and the sound reduction material is 10 to 30 parts by mass.

3. The thermoplastic resin composition according to Claim 1 or 2, wherein the sound reduction material has a mass ratio of the block (I) to the block (II) of the graft copolymer of block (I) / block (II) = 10 to 30 / 90 to 70, the content rate of the block copolymer is 1 to 80% by mass, and the graft rate is 8 to 35%.

4. A molded article comprising the thermoplastic resin composition according to any one of Claims 1 to 3.

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