JP2001207001A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition which has excellent stiffness, impact resistance, solvent resistance, specularity of the molded article and scratch resistance and which resists delamination. SOLUTION: This thermoplastic resin composition contains, based on 100 parts by mass of a resin mixture consisting of 5-95 mass % of a polystyrene- based resin and 95-5 mass % of a polyolefin-based resin, 1-50 parts by mass of a hydrogenated block copolymer obtained by hydrogenation of a block copolymer which comprises 35-70 mass % of a vinyl aromatic-based polymer block A and a conjugated diene-based polymer block B with a 1,2-vinyl linkage content and/or a 3,4-vinyl linkage content of 60-85%. The polyolefin-based resin is preferably a polypropylene-based resin. The hydrogenated block copolymer is preferably of (A-B)n-A type (wherein (n) is an integer of 1-10) or (A-B)m type (wherein (m) is an integer of 2-10).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition containing a polystyrene resin, a polyolefin resin and a hydrogenated block copolymer, and more particularly to a composition in which the hydrogenated block copolymer has a specific structure. The present invention relates to a thermoplastic resin composition which is excellent in impact resistance, solvent resistance, specularity of a molded product, scratch resistance, and is hardly delaminated.

[0002]

2. Description of the Related Art Polystyrene resins have high rigidity and surface rigidity, and can be used to obtain molded products having excellent mirror surface properties, as well as excellent moldability, recyclability, and scratch resistance.
In addition, because of its relatively low cost, it is used in various fields, but has a problem of poor solvent resistance. Further, polyolefin-based resins are excellent in oil resistance and solvent resistance, but have low rigidity and low surface rigidity, so that it is difficult to obtain a molded article having high specularity, and the molded article is easily damaged. As a means for solving these problems, a method of blending a polystyrene resin having excellent rigidity, specularity and scratch resistance with a polyolefin resin having excellent oil resistance and solvent resistance has been used. Polystyrene resin and polyolefin resin have poor compatibility,
Simply blending has a problem that the obtained material has low impact resistance and easily causes delamination.

For the purpose of improving the compatibility between a polystyrene resin and a polyolefin resin, a composition containing a hydrogenated elastomer of a styrene / conjugated diene copolymer as a compatibilizer is disclosed in, for example, JP-A-56-38338.
And JP-A-6-192501. However, conventionally used compatibilizers cannot satisfy the required properties such as impact resistance, solvent resistance, rigidity, and delamination resistance of the resin composition.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to add a hydrogenated block copolymer having a specific structure to a blend of a polystyrene resin and a polyolefin resin such as a polypropylene resin to obtain a rigid resin. An object of the present invention is to provide a thermoplastic resin composition which is excellent in mechanical properties such as tensile elongation at break, impact resistance, etc., has solvent resistance, is hardly delaminated, and has excellent mirror surface properties and scratch resistance of a molded product.

[0005]

That is, the present invention provides:
(C) 50% by mass of a vinyl aromatic monomer unit with respect to 100 parts by mass of a resin mixture composed of 5 to 95% by mass of a polystyrene resin and 95 to 5% by mass of a polyolefin resin such as a polypropylene resin. (A-B) nA type block copolymer (n is an integer of 1 to 10) or (A-B), comprising a vinyl aromatic polymer block A and a conjugated diene polymer block B containing more than B) m-type block copolymer (m is an integer of 2 to 10), and the content of vinyl aromatic monomer units in the copolymer is 35 to 70
% By mass, and 1,2-
Hydrogenating a block copolymer having a vinyl bond content and / or a 3,4-vinyl bond content of 60 to 85%,
A thermoplastic resin composition (D) comprising 1 to 50 parts by mass of a hydrogenated block copolymer obtained by hydrogenating 80% or more of the unsaturated bonds contained in the block B.

Further, the present invention provides the following invention. (1) In the thermoplastic resin composition (D), (A)
A thermoplastic resin composition characterized by using 100 parts by mass of a resin composition comprising 20 to 95% by mass of a polystyrene resin and 80 to 5% by mass of a polyolefin resin such as (b) a polypropylene resin. The present invention provides a thermoplastic resin composition (E) having higher rigidity and higher practicality depending on the product. (2) In the thermoplastic resin composition (D or E), (c) the thermoplastic resin composition wherein the hydrogenated block copolymer is composed of a styrene polymer block A and a butadiene polymer block B ( F).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polystyrene resin used as the component (A) of the present invention is a resin obtained by polymerizing a vinyl aromatic monomer represented by styrene, preferably in an amount of 70% by mass or more, for example, a styrene homopolymer. Impact-resistant polystyrene, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer obtained by graft-polymerizing a styrene monomer to a conjugated diene rubber elastomer. Polymer, styrene-maleic acid copolymer,
Or there are these mixtures.

In the above-mentioned polystyrene and styrene copolymer, instead of styrene, the following vinyl aromatic monomers: α-methylstyrene, α-ethylstyrene, vinyltoluene, vinylnaphthalene, vinylanthracene, 3-methylstyrene , 4-methylstyrene, 4
-Isopropylstyrene, 2,4-dimethylstyrene,
Chlorostyrene, bromostyrene, 2,4-dichlorostyrene, 2-chloro-4-methylstyrene, 2,6-dichloro-4-methylstyrene and the like can be used.

Incidentally, the melt flow rate of the polystyrene resin (a) used in the present invention (hereinafter referred to as MFR; MF)
The measurement condition of R is 2 in accordance with ASTM D1238.
00 ° C, 5 kg load. ) Is preferably 0.01
g / 10 minutes or more, more preferably 0.1 g / 10 minutes or more. When the MFR is within this range, the physical strength of the thermoplastic resin composition of the present invention is easily exhibited.

As the polyolefin resin used as the component (b) of the present invention, a polypropylene resin is preferable. As the polypropylene resin, a commonly used polypropylene resin can be used without any particular limitation. It may be a polymer, or a copolymer obtained by copolymerizing propylene with another monomer as shown below.

Preferred copolymerizable monomers used in the polypropylene copolymer include (1) linear monomers such as ethylene, butene-1, pentene-1, hexene-1, heptene-1, and octene-1. Α-olefin, (2) 2-methylpropene-1, 3-methylpentene-1, 4-methylpentene-1, 5-methylhexene-1, 4-methylhexene-1, 4,4-dimethylpentene- Branched α such as 1
-Olefins, (3) acrylic acid, methacrylic acid, ethacrylic acid, monocarboxylic acids such as crotonic acid, (4) maleic acid, fumaric acid, itaconic acid, dicarboxylic acids such as citraconic acid and its monoester, (5) methyl Methacrylate, methyl acrylate, acrylic acid such as ethyl acrylate, or methacrylic acid ester, (6) styrene,
α-styrene, vinyl aromatic compounds such as p-methylstyrene, (7) maleic anhydride, itaconic anhydride, citraconic anhydride, acid anhydrides such as aconitic anhydride, (8) α such as acrylonitrile and methacrylonitrile , Β-unsaturated nitriles, (9) diene monomers such as 1,4-hexadiene, dicyclopentadiene and ethylidene norbornene, and (10) acrylamide, methacrylamide, maleimide and the like.

These copolymerizable monomers may be used alone or in combination of two or more. The amount of these copolymer components is preferably 30% by mass or less, more preferably 20% by mass or less. The form of the copolymer when these are copolymerized is not particularly limited, and may be, for example, any of a random type, a block type, a graft type, and a mixture thereof.

The polypropylene copolymer may be any of generally used random copolymers, block copolymers and the like, and preferred examples are propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene- Ethylene-butene-1 copolymer is exemplified. These polypropylene resins can be used alone or in combination of two or more.

The (b) polyolefin-based resin of the present invention includes, for example, the above-mentioned polypropylene-based polymer or copolymer, and the like, acid anhydride group, carboxyl group, hydroxyl group, amino group, isocyanate group and epoxy group. And a functional group-containing polyolefin resin modified with at least one functional group selected from the group consisting of:

The MFR (230 ° C., 2.16 kg load) of the polyolefin resin (b) used in the present invention is:
It is preferably at least 0.01 g / 10 min, more preferably at least 0.1 g / 10 min. When the MFR is within this range, the physical strength of the thermoplastic resin composition of the present invention is easily exhibited.

In the above composition, the mass ratio of (a) a polystyrene resin to (b) a polyolefin resin such as a polypropylene resin is (a) / (b) = 5/95 to 95.
/ 5, preferably 20/80 to 95/5. When the polystyrene-based resin exceeds 95% by mass, the solvent resistance decreases, and when it is less than 5% by mass, the rigidity decreases.

The (c) hydrogenated block copolymer used in the present invention comprises a polymer block A and a polymer block B. The polymer block A is a homopolymer of a vinyl aromatic monomer or a vinyl aromatic monomer unit containing 50% by mass, preferably more than 70% by mass of a vinyl aromatic monomer unit, and a copolymer. It has a copolymer structure with other possible monomers, preferably conjugated diene monomers. The polymer block B has a structure in which a homopolymer of a conjugated diene monomer or another monomer such as a vinyl aromatic monomer is copolymerized at 5% by mass or less.

As described above, the (c) hydrogenated block copolymer of the present invention comprises a polymer block A mainly composed of a vinyl aromatic monomer and a polymer block B mainly composed of a conjugated diene monomer. And the block structure is (A-
B) nA type (n is an integer of 1 to 10) or (AB)
Although it is an m-type (m is an integer of 2 to 10) block copolymer, the A block at the end may have a relatively short B block. Also, [(AB) n] m-M type (M is a coupling agent residue such as Si or Sn, m is a valence of the coupling agent residue and is an integer of 2 to 4, and n is 1 to 10 , Preferably 1 or 2.). This block copolymer has A ₁ -B-A ₂
Type or A ₁ -B ₁ -A ₂ -B ₂ type,
Further, as described in claim 10, the block ratio of the block A is preferably less than 1, more preferably 0.5 or less. The weight average molecular weights of the blocks B ₁ and B ₂ may be the same, and the weight average molecular weight of B ₂ may be smaller.

Here, as the vinyl aromatic monomer used for the component (c), styrene, α-methylstyrene, p
-Methylstyrene, t-butylstyrene, divinylbenzene, N, N-dimethyl-p-aminoethylstyrene,
Examples thereof include 2,4-dimethylstyrene, N, N-diethyl-p-aminoethylstyrene, 2,4-dimethylstyrene, vinylnaphthalene, and vinylanthracene. Among them, styrene and α-methylstyrene are preferable.

The conjugated diene monomer used in the component (c) includes 1,3-butadiene, isoprene,
2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3
One or more of hexadiene, 4,5-dimethyl-1,3-octadiene, chloroprene and the like, among which 1,3-butadiene and isoprene are preferred.

In the polymer block A, other monomers copolymerizable with the vinyl aromatic monomer are mainly the above-mentioned conjugated diene monomers, and among them, 1,3-butadiene and isoprene are preferable.

Further, as the component (c), the hydrogenated block copolymer contains at least one functional group selected from an acid anhydride group, a carboxyl group, a hydroxyl group, an amino group, an isocyanate group and an epoxy group. The modified functional group may be used, or a blend of the hydrogenated block copolymer and the modified hydrogenated block copolymer in any ratio may be used.

(C) The content of the vinyl aromatic monomer unit in the hydrogenated block copolymer is 35 to 70% by mass, preferably 40 to 60% by mass. If the proportion of the vinyl aromatic monomer unit is less than 35% by mass, the rigidity of the composition is reduced, and if it is more than 70% by mass, the impact resistance of the composition is undesirably reduced.

(C) The bonding structure of the conjugated diene monomer in the hydrogenated block copolymer is 1,4- and 1,2- when the conjugated diene monomer is 1,3-butadiene. In the case of isoprene containing (vinyl) bonds,
Including 1,4-, 1,2- and 3,4-bonds (here, 1,2- and 3,4- are both called vinyl bonds). (C) 1,2- and / or 3,4 in the conjugated diene monomer unit in the hydrogenated block copolymer used in the present invention.
The vinyl bond content is 60-85%, preferably 65-85%; When the vinyl bond content is less than 60%,
The impact resistance of the composition decreases, and if it exceeds 85%, the rigidity decreases, which is not preferable.

In the (c) hydrogenated block copolymer used in the present invention, the hydrogenation rate of the unsaturated bond contained in the conjugated diene monomer unit is 80% or more, more preferably 85%.
Above, more preferably 90% or more. If the hydrogenation ratio is less than 80%, the rigidity and impact resistance of the composition are undesirably reduced. Further, the weight average molecular weight of the (c) hydrogenated block copolymer used in the present invention is preferably 5
000 to 1,000,000, more preferably 100
The range is from 00 to 500,000.

(C) The amount of the hydrogenated block copolymer to be added is 1 to 50 parts by mass based on 100 parts by mass of the total amount of (a) the polystyrene resin and (b) the polyolefin resin.
Preferably it is 2 to 20 parts by mass. (C) If the amount of the hydrogenated block copolymer is less than 1 part by mass, the effect of improving the physical properties is not sufficient, and if it exceeds 50 parts by mass, the rigidity is lowered, which is not preferable. In addition, one or both of (c) and a resin (d) compatible with (b) or a resin (e) compatible with (b),
This is preferable because the effect of improving the physical properties is greater than that of (c). The amount to be blended in advance is 3 per 100 parts by mass of (c).
The amount is more preferably 0 parts by mass or less, and further preferably 20 parts by mass or less. Note that a blend of two or more hydrogenated block copolymers may be used as long as the content is within the above range.

The composition of the present invention may contain, if necessary, various additives such as an antioxidant, a weathering agent, a metal deactivator, a light stabilizer, an ultraviolet absorber, a heat stabilizer, and a copper damage inhibitor. Stabilizers, antibacterial and antifungal agents, dispersants, softeners, plasticizers, silicone oils, flame retardants, crosslinking agents, co-crosslinking agents, vulcanizing agents, vulcanizing aids, foaming agents, foaming aids, Coloring agents such as titanium oxide and carbon black, metal powders such as ferrite, glass fibers,
Inorganic fibers such as metal fibers, carbon fibers, organic fibers such as aramid fibers, composite fibers, inorganic whiskers such as potassium titanate whiskers, glass beads, glass balloons, glass flakes, asbestos, mica, calcium carbonate,
Fillers such as talc, silica, calcium silicate, hydrotalcite, kaolin, diatomaceous earth, graphite, pumice, evo powder, cotton floc, cork powder, barium sulfate, fluororesin, polymer beads, or mixtures thereof, polyolefin wax , Cellulose powder,
Fillers such as rubber powder, low molecular weight polymers and the like can be blended and used. Further, a rubbery polymer, a thermoplastic resin other than the essential thermoplastic resin, and the like can be appropriately compounded so as not to impair the effects of the present invention.

In producing the thermoplastic resin composition of the present invention, a conventionally known kneading machine such as an extruder, a pressure kneader and a Banbury mixer, and a kneading machine combining these can be used. In kneading, each component may be kneaded at once, or a multi-stage kneading method may be adopted in which after kneading arbitrary components, the remaining components are added and kneaded. The resin composition thus obtained can be molded by a known method such as injection molding, extrusion molding, rotational molding, press molding, and hollow molding.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The percentages and parts in the examples are on a mass basis unless otherwise specified. The various chemical compositions and evaluations in the examples are values and evaluations measured as follows.

(1) Content of bound vinyl aromatic compound The content was measured by infrared analysis based on the absorption of a phenyl group at 679 cm ^-1 . (2) Vinyl bond content of conjugated diene Calculated by Morero method using infrared analysis. (3) Hydrogenation rate Calculated from 90 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.

(4) Weight average molecular weight The weight average molecular weight was determined in terms of polystyrene by gel permeation chromatography (GPC) at 38 ° C. using tetrahydrofuran as a solvent. (5) Rigidity According to ASTM D790, the three-point bending test method
The flexural modulus was measured under a temperature condition of 23 ° C. and used as an index of rigidity. (6) Impact Resistance According to ASTM D256, Izod impact strength was measured at a temperature of 23 ° C. using an Izod impact tester, and was used as an index of impact resistance. (7) Tensile Elongation at Break In accordance with ASTM D638, a tensile test was performed on the test piece (Type 1) under a temperature condition of 23 ° C. to measure the tensile elongation at break.

(8) Solvent Resistance Test A test piece obtained by injection molding the resin composition was immersed in toluene at 23 ° C., and whether or not the test piece dissolved was visually evaluated according to the following criteria. ：: No change at all. Δ: Not dissolved, but surface gloss is lost. ×: completely dissolved. (9) Delamination resistance A cut is made with a cutter on a test piece obtained by molding the resin composition into a flat plate by injection molding, and a cellotape (registered trademark) is attached to the cut, followed by pulling to determine whether or not the surface is peeled. Was visually observed and visually evaluated according to the following criteria. ：: The surface does not peel off. X: The surface peels off.

(10) Surface Impact Resistance As another index indicating the impact resistance, the surface impact resistance was measured. 3.2 thickness obtained by injection molding of the resin composition
mm plate was placed on a 25 mmφ hole, and a 15.7 mmφ hitting bar having a hemispherical tip was used for 2.4 m.
The breaking energy was calculated from the displacement and the load until the test piece was broken, and the magnitude was used as an index of surface impact resistance. The larger the value, the higher the surface impact resistance, which is preferable. (11) Specularity The resin composition is 80 mm × 55 at 220 ° C. by injection molding.
The specularity of a test piece molded into a flat plate of mm × 2.4 mm was visually judged according to the following criteria. ：: The distortion of the image reflected on the test piece is small. X: The image reflected on the test piece has a large distortion.

[1] Production of Block Copolymer (C) (Polymerization Example 1) In a 5 liter autoclave, 2.5 kg of cyclohexane, 15 g of tetrahydrofuran,
165 g of styrene (block A component) and 0.55 g of n-butyllithium were added, polymerization was carried out at 50 ° C. to a polymerization conversion of 98% or more, and then 220 g of 1,3-butadiene (block B component) was added. , 98% polymerization conversion
Polymerization was carried out until the above was reached, and 165 g of styrene (block A component) was further added to polymerize to a polymerization conversion of 100%.

After the polymerization was completed, the reaction solution was heated to 70 ° C., and 0.33 g of n-butyllithium and t-hydroxy-4-methyl-
0.61 g of 2-pentanone, 0.21 g of bis (cyclopentadienyl) titanium dichloride and 0.76 g of diethylaluminum chloride were added, and a hydrogen pressure of 1
The reaction was carried out at 0 kg / cm ² for 1 hour and hydrogenated. This reaction solution was mixed in a large amount of methyl alcohol, and the precipitated solid was recovered and dried to obtain a block copolymer.
The obtained hydrogenated block copolymer (C-1) was prepared from A-
B-A type, the degree of hydrogenation is 98%, the 1,2-vinyl bond content in the polybutadiene of the block B is 65%,
The weight average molecular weight was 110,000.

(Polymerization Examples 2 to 10) By changing the kind of monomer, the amount of monomer, the amount of catalyst, the polymerization temperature, the polymerization time, etc., the hydrogenated block copolymer as shown in Table 1 was obtained. ,
Hydrogenated block copolymers (C-2 to C-10) were obtained according to the hydrogenated block copolymer (C-1). In addition, (c-4) was manufactured using isoprene instead of 1,3-butadiene for the block B component.

The various components used in the formulations of the examples, comparative examples and evaluations are as follows. (A) Component Polystyrene: [H554: Nippon Polystyrene Co., Ltd.
MFR: 3 g / 10 min (200 ° C., 5 kg)] (b) Component Polypropylene [J705: manufactured by Grand Polymer Co., Ltd., MFR: 10 g / 10 min (230 ° C., 2.16 k)
g)]

(C) Component The hydrogenated block copolymer (C-1 to C-10) was used. The microstructures and hydrogenation rates of these block copolymers are as shown in Tables 1 and 2. In addition, (ha-1 to ha-5) of Table 1 is a hydrogenated block copolymer used in the present invention, and (ha-6 to ha-10) of Table 2 is
It is a hydrogenated block copolymer outside the scope of the present invention.

[0039]

[Table 1]

[0040]

[Table 2]

Description of Tables 1 and 2: ST is styrene, BD is butadiene, and IP is isoprene. The vinyl content is
The content is 1,2-vinyl for BD and 1,2- and 3,4-vinyl for IP. H / D is the content ratio (mass ratio) of the vinyl aromatic monomer unit (H) and the conjugated diene monomer unit (D) in the block copolymer.

[2] Examples 1 to 7 and Comparative Examples 1 to 8 The above components (a), (b) and (c) are shown in Tables 3 and 4
And melt-kneaded using a twin-screw extruder to form pellets. Next, test pieces for evaluating physical properties were prepared by injection molding. The results of the physical property evaluation are also shown in Tables 3 and 4.

[0043]

[Table 3]

[0044]

[Table 4]

From the results of Examples 1 to 7 shown in Table 3, it was found that the resin composition of the present invention was excellent in rigidity, impact resistance, tensile elongation at break, solvent resistance and delamination resistance. When the end block structure is asymmetric, the fluidity is increased, the moldability is improved, and the mechanical properties are also improved. On the other hand, with respect to Comparative Examples shown in Table 4, Comparative Example 1 is inferior in solvent resistance because the mass ratio of polystyrene-based resin to polypropylene-based resin is out of the range of the present invention. In Comparative Examples 2 and 3, since the content of the hydrogenated block copolymer was out of the range of the present invention, Comparative Example 2 had impact resistance, tensile elongation at break,
The solvent resistance and the delamination resistance are inferior, and Comparative Example 3 is inferior in rigidity. Comparative Examples 4 and 5 are inferior in impact resistance, rigidity, and delamination resistance because the content of the vinyl aromatic monomer unit in the hydrogenated block copolymer is out of the range of the present invention. Comparative Example 5 is inferior in impact resistance and delamination resistance. Comparative Examples 6 and 7 are inferior in impact resistance, tensile elongation at break and delamination resistance because the vinyl bond content of the conjugated diene portion in the hydrogenated block copolymer is out of the range of the present invention, Comparative Example 7 is inferior in rigidity and delamination resistance. Comparative Example 8
Since the hydrogenation rate of the conjugated diene portion in the hydrogenated block copolymer is out of the range of the present invention, rigidity, impact resistance,
Poor in tensile elongation at break and delamination resistance.

[3] Examples 8 to 9 and Comparative Examples 9 to 10 (a) The component content is low and the (b) component content is high. Table 5 and the (a) component content is low and the (b) component content is high. ,
(C) Each component was mixed according to the formulation shown in Table 6 containing no component, melt-kneaded using a twin-screw extruder, and pelletized. Next, a test piece for evaluating physical properties was prepared by injection molding, and the physical properties were evaluated by paying particular attention to surface impact resistance and specularity. The results of the physical property evaluation are also shown in Tables 5 and 6.

[0047]

[Table 5]

[0048]

[Table 6]

From the results of Examples 8 and 9 shown in Table 5, the resin composition of the present invention has an excellent balance of rigidity, surface impact resistance, tensile elongation at break, solvent resistance, delamination resistance, and specularity. When the end block structure becomes asymmetric, the curvature of the interface changes, so that the compatibility is improved and the mechanical properties are improved.
High fluidity and excellent moldability. As for Comparative Examples shown in Table 6, Comparative Example 9 is inferior in specularity because the mass ratio of polystyrene resin to polypropylene resin is out of the range of the present invention. Comparative Example 10 is inferior in impact resistance and delamination resistance because the content of the hydrogenated block copolymer is out of the range of the present invention.

[0050]

The resin composition obtained according to the present invention comprises:
By adding a hydrogenated block copolymer having a specific structure, the compatibility between polystyrene resin and polyolefin resin such as polypropylene resin is improved,
It is a material with excellent impact resistance, rigidity, solvent resistance, tensile elongation at break, and delamination resistance, and its application fields are food packaging containers, various trays, sheets, tubes, films, fibers, laminates, Various industrial parts such as coating materials, electrical and electronic parts such as connectors and printed circuit boards, OA equipment such as computers, housings of home electric appliances, automobile parts, precision parts, and building materials.

Claims (10)

[Claims] 1. A vinyl aromatic monomer unit (C) is added to 100 parts by mass of a resin mixture consisting of (A) 5 to 95% by mass of a polystyrene resin and (B) 95 to 5% by mass of a polyolefin resin. It comprises a vinyl aromatic polymer block A and a conjugated diene polymer block B containing more than 50% by mass, and has a vinyl aromatic monomer unit content of 3%.
5 to 70% by mass, and a block copolymer having a 1,2-vinyl bond content and / or a 3,4-vinyl bond content in a conjugated diene monomer unit of 60 to 85% is hydrogenated. 80 of the unsaturated bond in the copolymer
% Of a hydrogenated block copolymer obtained by hydrogenation in an amount of 1 to 50 parts by mass. 2. The method according to claim 1, wherein (a) the polystyrene resin is 20 to
2. The thermoplastic resin composition according to claim 1, wherein the content of the polyolefin resin is 80 to 5% by mass. 3. The method according to claim 1, wherein (a) the polystyrene resin is 50 to 50%.
2. The thermoplastic resin composition according to claim 1, wherein the content of the polyolefin resin is 50 to 5% by mass. 4. The method according to claim 1, wherein (a) the polystyrene resin is 5 to 5
0% by mass, and the content of the polyolefin resin (b) is 9%.
The thermoplastic resin composition according to claim 1, wherein the content is 5 to 50% by mass. 5. The thermoplastic resin composition according to claim 1, wherein (a) the polyolefin resin is a polypropylene resin. 6. The method according to claim 1, wherein said (c) hydrogenated block copolymer has at least one vinyl aromatic polymer block A and at least one conjugated diene polymer block B. The thermoplastic resin composition according to claim 1. 7. The thermoplastic resin composition according to claim 1, wherein (c) the hydrogenated block copolymer comprises a styrene polymer block A and a butadiene polymer block B. 8. The structure of the (c) hydrogenated block copolymer is (AB) nA type (n is an integer of 1 to 10) or (AB) m type (m is 2 to 10). The thermoplastic resin composition according to any one of claims 1 to 7, wherein the thermoplastic resin composition is a block copolymer represented by the following formula: 9. The method according to claim 1, wherein the structure of the (c) hydrogenated block copolymer is an ABA type or an ABAB type block copolymer. 5. The thermoplastic resin composition according to item 1. 10. The weight average molecular weight of A ₁ , wherein one of the vinyl aromatic polymer blocks of the hydrogenated block copolymer (A) is A ₁ and the other vinyl aromatic polymer block is A _2. [Mw (a _1)] and a larger denominator value of the weight average molecular weight of the _{a 2 [Mw (a 2)} ] ratio of [Mw (a ₁₎ and Mw (a _2). The thermoplastic resin composition according to claim 9, wherein the block ratio is less than 1.