JPH11116749A - Thermoplastic resin composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition containing a styrene resin and an inorganic filler, wherein the dispersedness of the inorganic filter and the adhesion of the matrix resin to the inorganic filler are improved, and as a result the mechanical properties and the water resistance are improved. SOLUTION: This composition is obtained by mixing a styrene resin (I) with an inorganic filler (II) and a specified block copolymer (III) under heating. Block copolymer III is one having a polymer chain (A) containing 50-100 wt.% vinylaromatic monomer units and 50-0 wt.% (hydrogenated) conjugated diene units and having a number-average molecular weight of 20,000-200,000 and a polymer block (B) containing at least 30 mol.% t-alkyl (meth)acrylate units (the content of polymer block B is 0.5-30 wt.%). The amounts of the respective components satisfy the following relationships: (I):(II)=98:2 to 40:60, and ((I)+(II)):(III)=100:0.1 to 100:20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a styrene resin,
Thermoplastic resin composition obtained by heating and mixing a specific block copolymer containing a polymer block containing an inorganic filler and a tertiary alkyl ester unit of methacrylic acid or acrylic acid, and the thermoplastic resin composition And a method for producing the same. The thermoplastic resin composition of the present invention is derived from the use of the block copolymer, compared to a resin composition consisting of only a styrene resin and an inorganic filler, the dispersion of the inorganic filler in the resin composition. Since the properties and the adhesion between the polymer component and the inorganic filler are improved, the mechanical properties evaluated by bending strength, Izod impact strength and the like are improved, and the water resistance is also improved.

[0002]

2. Description of the Related Art A styrene resin can supplement or improve its mechanical properties by blending an inorganic filler. Syndiotactic styrene resin (hereinafter referred to as “syndiotactic polystyrene”)
) Is the heat resistance, chemical resistance, and dimensional stability associated with the high crystallinity derived from its stereoregularity while maintaining the excellent physical properties of ordinary polystyrene such as low specific gravity, high insulation properties, and good moldability. It is an engineering plastic that has excellent properties in terms of properties and is useful as parts for electrical equipment and automobiles.Syndiotactic polystyrene also incorporates an inorganic filler such as glass fiber, It is known to improve properties.

However, in a thermoplastic resin composition comprising a styrene resin and an inorganic filler, since the matrix component comprising the resin is non-polar, it is difficult to satisfactorily disperse the inorganic filler having a polar surface. Have difficulty. Therefore, in order to improve the dispersibility, a method of increasing the affinity between the surface of the inorganic filler and the matrix resin by, for example, a silane coupling treatment on the surface of the inorganic filler is generally adopted.

[0004]

According to the study of the present inventors, a thermoplastic resin composition comprising a styrenic resin such as syndiotactic polystyrene and an inorganic filler is subjected to the above-mentioned silane coupling treatment. Even if techniques such as are taken, depending on the application, the dispersibility and the adhesion between the matrix resin and the inorganic filler are not necessarily sufficient, and the mechanical properties are insufficient, or It has been found that the deterioration of physical properties over time during contact may not be ignored.

An object of the present invention is to provide a thermoplastic resin composition comprising a styrene-based resin such as syndiotactic polystyrene and an inorganic filler as main components. An object of the present invention is to provide a thermoplastic resin composition having good adhesiveness and improved mechanical properties and water resistance. Another object of the present invention is to provide a simple method for producing a thermoplastic resin composition having such features.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, when producing a thermoplastic resin composition by heating and mixing a styrene resin and an inorganic filler, By blending a small amount of a specific block copolymer, the dispersibility of the inorganic filler and the adhesiveness between the matrix resin and the inorganic filler are significantly improved, and the thermoplastic resin composition has excellent mechanical properties and water resistance. Were found, and as a result of further study, the present invention was completed.

That is, the present invention firstly provides:

(1) A thermoplastic resin composition obtained by heating and mixing the following components (I), (II) and (III);

Component (I): styrenic resin;

Component (II): inorganic filler;

Component (III): Containing at least one polymer block, containing 50 to 100% by weight of a vinyl aromatic monomer unit, and containing an optionally hydrogenated conjugated diene unit. A polymer chain (A) having an amount of 50 to 0% by weight and a number average molecular weight of 20,000 to 200,000, and a structural unit in which a tertiary alkyl ester unit of methacrylic acid or acrylic acid accounts for 30 mol% or more. A block copolymer having a polymer block (B) comprising: and a content of the polymer block (B) is 0.5 to 30% by weight;

(2) The weight ratio of component (I) to component (II) is from 98: 2 to 40:60 in (I) :( II).
Is within the range of

(3) A thermoplastic resin wherein the weight of component (III) used is in the range of 0.1 to 20 parts by weight based on 100 parts by weight of the total weight of components (I) and (II). It is a resin composition.

The present invention also provides, secondly,

(1) The component (I), the component (II) and the component (III) are mixed at a weight ratio of the component (I) to the component (II) of (I) :( II) of 98: 2. -40: 60, and the weight of the component (III) is 0.1 to 100 parts by weight of the total weight of the components (I) and (II).
Used in proportions that fall within the range of ２０20 parts by weight;

(2) A method for producing a thermoplastic resin composition, which comprises mixing the above-mentioned components (I), (II) and (III) by heating.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A styrene resin as the component (I) used in the present invention (hereinafter referred to as "styrene resin (I)")
) Is a general term for a polymer whose main component is a styrene unit and a modified product obtained by dispersing rubber particles and the like in the polymer. For example, a polystyrene resin, a rubber-reinforced polystyrene resin (HIPS) , A syndiotactic polystyrene resin (SPS) whose steric structure is syndiotactic, an acrylonitrile-styrene copolymer (A
S), acrylonitrile-butadiene-styrene copolymer (ABS) and the like.

Examples of the inorganic filler which is the component (II) used in the present invention (hereinafter sometimes referred to as "inorganic filler (II)") include, for example, glass fiber; talc, clay, kaolin, mica and the like. Oxides such as silica, titanium oxide, iron oxide and zinc oxide; hydroxides such as aluminum hydroxide and magnesium hydroxide; carbonates such as calcium carbonate and magnesium carbonate; barium sulfate and calcium sulfate Sulfate; carbon black and the like, and the shape thereof includes various forms such as powder and fiber. These inorganic fillers are not limited to one kind, and two or more kinds may be used in combination.

The above-mentioned block copolymer (hereinafter referred to as “block copolymer (II)” which is the component (III) used in the present invention.
I))) is composed of at least one polymer block, and has a vinyl aromatic monomer unit or a conjugated diene unit which may be hydrogenated as a main structural unit. It contains a polymer chain (A) and a polymer block (B) having a tertiary alkyl ester unit of methacrylic acid or acrylic acid as an essential structural unit.
The polymer chain (A) has a number average molecular weight of at least 2,000 to 2,000, which is composed of at least one polymer block.
The polymer chain of No. 00 is composed of 50 to 100% by weight of a vinyl aromatic monomer unit, and 50 to 0% by weight of a conjugated diene unit which may be hydrogenated. On the other hand, the polymer block (B) has a tertiary alkyl ester unit of methacrylic acid or acrylic acid as a structural unit of 30 units.
It is a polymer block contained at a ratio of not less than mol% and accounts for 0.5 to 30% by weight of the block copolymer (III).

The vinyl aromatic monomer unit in the polymer chain (A) is a structural unit introduced by addition polymerization of a vinyl aromatic monomer.
For example, styrene; alkyl-substituted styrene such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-tert-butylstyrene; p-chlorostyrene, m-chlorostyrene, p-bromostyrene, m-bromostyrene Halogenated styrenes such as p- (chloromethyl) styrene, m- (chloromethyl) styrene, p-
Halogenated alkyl-substituted styrenes such as (bromomethyl) styrene and m- (bromomethyl) styrene; and alkoxy-substituted styrenes such as p-methoxystyrene and p-tert-butoxystyrene. One or more of these vinyl aromatic monomers can be used.

The content of the vinyl aromatic monomer unit in the polymer chain (A) is at least 50% by weight, but when the content is less than 50% by weight, the block copolymer weight with the styrene resin (I) is reduced. The compatibility with the coalescence (III) is reduced, and the dispersibility of the inorganic filler (II) becomes insufficient. From this viewpoint, the content of the vinyl aromatic monomer unit is more preferably 60% by weight or more.

The conjugated diene unit which may be contained in the polymer chain (A) at a ratio of 50% by weight or less and which may be hydrogenated is a structural unit introduced by addition polymerization of a conjugated diene or the conjugated diene unit. This is a structural unit obtained by hydrogenating the carbon-carbon double bond portion in the structural unit. When the polymer chain (A) contains a conjugated diene unit which may be hydrogenated,
The unit may be one of a non-hydrogenated conjugated diene unit and a hydrogenated conjugated diene unit, or may be both, for the production of the thermoplastic resin composition of the present invention. For the purpose of preventing deterioration during heating and mixing of the above and improving the thermal stability and weather resistance of the obtained resin composition itself, it is preferable that the ratio of the hydrogenated conjugated diene unit is high. As the conjugated diene, for example, one or more kinds such as butadiene and isoprene can be used.

The polymer chain (A) may contain a small proportion of a structural unit different from the vinyl aromatic monomer unit and the conjugated diene unit as long as the effects of the present invention are not impaired.

The polymer chain (24A) is typically a homopolymer chain of a vinyl aromatic monomer or a copolymer chain of a vinyl aromatic monomer and a conjugated diene (the conjugated diene unit is partially Or may be completely hydrogenated), but in the case of a copolymer chain, the monomer sequence in the chain is not particularly limited, and a random copolymer, a tapered copolymer,
Any form such as a block copolymer may be used.

The number average molecular weight of the polymer chain (A) is 2,000
Within the range of 0 to 200,000, but the number average molecular weight is 2
When it is less than 0000 or more than 200,000, the compatibility between the styrenic resin (I) and the block copolymer (III) decreases, and the dispersibility of the inorganic filler (II) becomes insufficient. When the number average molecular weight is less than 20,000,
The mechanical strength of the obtained thermoplastic resin composition becomes insufficient. From these viewpoints, the number average molecular weight is 30,000 to
It is preferably in the range of 160000.

The tertiary alkyl ester unit of methacrylic acid or acrylic acid contained in the polymer block (B) refers to a tertiary alkyl ester of methacrylic acid or tertiary alkyl ester of acrylic acid. The structural unit to be introduced. As the tertiary alkyl ester of methacrylic acid, tert-butyl methacrylate,
Examples of 1,1-dimethylethyl methacrylate and the like, and examples of the tertiary alkyl ester of acrylic acid include tert-butyl acrylate and 1,1-dimethylethyl acrylate, etc. Two or more types can be used. When the methacrylic acid or acrylate unit contained in the polymer block (B) is other than the tertiary alkyl ester, the matrix polymer component and the inorganic filler in the obtained thermoplastic resin composition It does not contribute to the improvement in the adhesiveness between them.

The content of the tertiary alkyl ester unit of methacrylic acid or acrylic acid in the polymer block (B) is 30 mol% or more based on all structural units contained in the polymer block (B). When the content is less than 30 mol%, the adhesiveness between the inorganic filler (II) and the polymer component constituting the matrix decreases, and the physical properties of the obtained thermoplastic resin composition are impaired.

The polymer block (B) includes a block of a homopolymer of a tertiary alkyl ester of methacrylic acid or acrylic acid.
If it is not more than mol%, it may contain a structural unit other than the tertiary alkyl ester unit of methacrylic acid or acrylic acid. In the latter case, the polymer block (B) contains the tertiary alkyl ester of methacrylic acid or acrylic acid. It becomes a block of a copolymer of a lower alkyl ester and another monomer. As the other monomer, for example, styrene, α-methylstyrene, p-
Methylstyrene, m-methylstyrene, p-tert-
Butylstyrene, p-chlorostyrene, m-chlorostyrene, p-bromostyrene, m-bromostyrene, p-
(Chloromethyl) styrene, m- (chloromethyl) styrene, p- (bromomethyl) styrene, m- (bromomethyl) styrene, p-methoxystyrene, p-tert
-Vinyl aromatic compounds such as butoxystyrene; methacryls such as methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, acrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, methacrylic acid Acid or acrylic acid or a primary or secondary alkyl ester thereof; acrylonitrile; a monomer having an ethylenically unsaturated bond, such as vinyl acetate, and the like. May be included. The monomer sequence in the block of the copolymer is not particularly limited, and may be any of a random copolymer and a tapered copolymer.

The number average molecular weight of the polymer block (B) is not necessarily limited, but may be from 1,000 to 1,000.
Preferably it is in the range of 50,000.

The block copolymer (III) may have at least one polymer chain (A) and at least one polymer block (B), but the polymer chain (A) has at least one polymer chain. Since the block copolymer (III) is composed of coalesced blocks, the arrangement of the polymer blocks that can be taken by the block copolymer (III) includes various arrangements. A polymer block having a vinyl aromatic monomer unit as a main structural unit is “S”, a polymer block having a conjugated diene unit which may be hydrogenated as a main structural unit is “D”, and a polymer block (B ) Is represented by "B", the block copolymer (III)
Representative examples of the arrangement of the polymer blocks in the above are shown below.

[0031]

## STR1 ## SB (linear diblock copolymer) SSD (linear triblock copolymer) SSDB (linear tetrablock copolymer) BS- B (linear triblock copolymer) BSSDB (linear pentablock copolymer) S (-B) m (radial block copolymer) S (-DSB) n (radial block copolymer)

(Wherein, m and n each represent an integer of 3 or more)

The content of the polymer block (B) in the block copolymer (III) is in the range of 0.5 to 30% by weight. When the content is less than 0.5% by weight, the adhesiveness between the matrix polymer component and the inorganic filler (II) becomes insufficient, and when the content exceeds 30% by weight, the water resistance of the obtained thermoplastic resin composition And other properties become insufficient. From these viewpoints, the content is more preferably in the range of 2 to 30% by weight.

Although the number average molecular weight of the block copolymer (III) is not necessarily limited,
It is preferable to be within the range of 300,000.

The block copolymer (II) used in the present invention
The production method of I) is not particularly limited,
It can be produced according to a known method such as an anionic living polymerization method using an organic alkali metal compound as an initiator (a partial hydrogenation reaction may be performed thereafter if desired).

The thermoplastic resin composition of the present invention is produced by heating and mixing a styrene resin (I), an inorganic filler (II) and a block copolymer (III). At the time of mixing, styrene resin (I) and inorganic filler (II)
Used weight ratio ((I) :( II)) is 98: 2 to 40: 6
0, and the total weight of the styrene resin (I) and the inorganic filler (II) used is 100 parts by weight of the block copolymer (III) in the range of 0.1 to 20 parts by weight. Is within. Styrene resin (I) / inorganic filler (I
When the value of the used weight ratio of I) is larger than 98/2, for example, effects derived from the inorganic filler such as improvement in flexural modulus are not sufficiently exhibited. Styrene resin (I) /
When the value of the weight ratio of the inorganic filler (II) used is smaller than 40/60, impact resistance, molding workability and the like are reduced.
Block copolymer (III) based on a total of 100 parts by weight of styrene resin (I) and inorganic filler (II) used
When the use weight of is less than 0.1 part by weight, the adhesiveness between the matrix polymer component and the inorganic filler becomes insufficient. In addition, styrene resin (I) and inorganic filler (II)
When the use weight of the block copolymer (III) is more than 20 parts by weight with respect to the total use weight of 100 parts by weight, excellent characteristics derived from the styrene resin (I) used cannot be exhibited.

During the production of the thermoplastic resin composition of the present invention, various components other than the above-mentioned components (I), (II) and (III) may be used depending on the purpose within a range that does not impair the effects of the present invention. Additives may be added to impart desired properties.
For example, engineering plastics such as nylon 6, nylon 66, etc. can be added to improve moldability, bending strength and tensile strength. Rubber-like polymers (for example, natural rubber, polybutadiene, polyisoprene, hydrogenated products of these diene polymers, polyisobutylene,
Neoprene, ethylene-propylene copolymer rubber, acrylic rubber, urethane rubber, silicone rubber, styrene
Diene block copolymer or hydrogenated product thereof, polyetherester rubber, polyester elastomer, etc.)
Can be blended. Further, pigments, antioxidants, heat aging inhibitors, ultraviolet absorbers, processing aids, lubricants, foaming agents, crystal nucleating agents and the like can also be added.

In the heating and mixing of the above components (I), (II) and (III) and other additives used as desired, the adhesiveness between the matrix polymer component and the inorganic filler is particularly improved. From the point of view, the temperature is preferably set to 150 ° C. or higher, more preferably 180 ° C. or higher. The upper limit of the heating and mixing temperature is not particularly limited, but if it is too high, the styrene resin (I) and the block copolymer (III) may be decomposed. . In the heating and mixing according to the present invention, an intramolecular condensation reaction occurs between two adjacent tertiary alkyl ester units of methacrylic acid or acrylic acid in the block copolymer (III), and a polymer main component is formed. It is assumed that a glutaric anhydride type six-membered ring structure is formed in the chain.

The order of heating and mixing the components (I), (II) and (III) is not particularly limited, and a method comprising simultaneously mixing the three components may be employed. It is also possible to employ a method comprising mixing the block copolymer (III) in advance with II) and then heating and mixing with the styrene resin (III). In the heating and mixing, it is possible to adopt a method according to a usual melt blending, for example, melt kneading using a melt kneading machine such as a single screw extruder, a twin screw extruder, a pravender, a Banbury mixer, a calender roll. Is preferred.

The thermoplastic resin composition of the present invention can be melt-molded or heated, and can be extruded, calendered,
Various forms of molded products such as films, sheets, and three-dimensional objects can be smoothly manufactured by any molding method such as injection molding.

[0041]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. In the following synthesis examples of the block copolymer, the following analysis methods and analysis equipment were used.

(Molecular Weight Measurement) GPC (“HL” manufactured by Tosoh Corporation)
C-8020 ”), the column“ GMHX
L "," G5000HXL "," G4000HXL "
(Each manufactured by Tosoh) with a flow rate of 1.0
It was measured under the condition of ml / min.

(Gas chromatography) "G" manufactured by Shimadzu
C-14A "(Column:" NEUTRABOND-1 "manufactured by GL Sciences Inc.)

( ¹ H-NMR) “JNM-L” manufactured by JEOL Ltd.
A400 / WB "

In Examples and Comparative Examples, the flexural modulus,
Bending strength, Izod impact strength and deflection temperature under load are
It was measured by the following method.

(Flexural modulus and flexural strength) ASTM D
790.

(Izod Impact Strength) ASTM D2
Measured according to 56 (notched).

(Deflection temperature under load) ASTM D648
(0.45 MPa). In Examples and Comparative Examples, the accelerated test in hot water for evaluating water resistance was performed by the following method.

(Hot Water Treatment Test) The test piece was immersed in hot water at 120 ° C. for 500 hours in an autoclave, and the obtained test piece was subjected to bending elastic modulus, bending strength, Izod impact strength and load deflection by the above-mentioned methods. The temperature was measured. The degree of deterioration in the hot water treatment was evaluated by comparing the measured value with a similar measured value in a test piece not subjected to the hot water treatment, and this was used as a criterion of water resistance.

The following components were used in Examples and Comparative Examples. Styrene resin (I): syndiotactic polystyrene (“Zarek S100” manufactured by Idemitsu Petrochemical Co., Ltd.)

Inorganic filler (II): glass fiber ("ECS03T-187 / P" manufactured by NEC Corporation)

Block copolymer (III): Block copolymer (III-1) produced by the following synthesis example
Or (III-2)

Synthesis Example 1 [Synthesis of polystyrene-b-poly (tert-butyl methacrylate) (III-1)] The inside of a 5-liter three-necked flask equipped with a stirring blade was replaced with dry nitrogen, and the mixture was dried in the presence of metallic sodium. 2700 g of tetrahydrofuran purified by distillation was added under a nitrogen atmosphere with a syringe equipped with a needle. The flask was immersed in a dry ice / methanol bath, and tetrahydrofuran was added at -77.
7. Cooled to 12 ° C. and added with 12% by weight of sec-butyllithium in cyclohexane solution (manufactured by Asia Lithium Co.)
0 ml was added with a syringe with a needle under a nitrogen atmosphere. 513 g of a styrene monomer distilled twice under reduced pressure in the presence of calcium hydride was dropped into this flask over 1 hour with a syringe with a needle under a nitrogen atmosphere, and styrene was further polymerized for 1 hour. Thereafter, a part of the reaction mixture was taken out, and the unreacted monomer concentration was measured by gas chromatography. As a result, it was found that the polymerization rate was 99% or more.
The Mn (number average molecular weight) of the obtained polystyrene was 54000, and the molecular weight distribution (Mw / Mn) was 1.0.
It was 5.

Into a flask containing a reaction mixture containing a living polymer of polystyrene obtained above, t-methacrylic acid t
27 g of tert-butyl monomer was added dropwise with a syringe with a needle under a nitrogen atmosphere, and then tert-butyl methacrylate was polymerized at −77 ° C. for 3 hours. The polymerization was then stopped by dropping 1 ml of methanol into the flask with a syringe with a needle. A part of the obtained reaction mixture was taken out, and the unreacted monomer concentration was measured by gas chromatography analysis.
It was found that the conversion of tert-butyl was 99% or more. The resulting reaction mixture was heated to room temperature and poured into 30 liters of methanol. The precipitated polymer is
Collected by vacuum filtration. The yield of the polymer was 97%, indicating that the polymerization had proceeded quantitatively. The Mn (number average molecular weight) of the obtained polymer was 56,000, and the molecular weight distribution (Mw / Mn) was 1.05.

From the above, the polymer (III-1) finally obtained is a diblock copolymer of polystyrene-b-poly (tert-butyl methacrylate), and poly (tert-butyl methacrylate). Butyl) block (content of tert-butyl methacrylate unit: 100 mol%)
Is 5.1% by weight, and as a polymer chain other than the block, a polystyrene block having an Mn (number average molecular weight) of 54000 (styrene unit content: 10
0% by weight).

Synthesis Example 2 [Synthesis of polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (tert-butyl methacrylate) (III-2)] In a 2 liter autoclave, the presence of sodium metal was added. The cyclohexane distilled and purified in 1500 g was added with a syringe equipped with a needle, and nitrogen bubbling was performed for 3 hours to replace the atmosphere in the autoclave with nitrogen. The temperature of the autoclave was raised to 40 ° C., and the
6.0 ml of a cyclohexane solution of c-butyllithium (manufactured by Asia Lithium Co., Ltd.) was added by a syringe with a needle under a nitrogen atmosphere. Further, 163 g of a styrene monomer distilled twice under reduced pressure in the presence of calcium hydride was added by a syringe with a needle under a nitrogen atmosphere, and polymerization of styrene was performed for 3 hours. Thereafter, a part of the reaction mixture was taken out, and the molecular weight was measured by GPC. The Mn (number average molecular weight) of the produced polystyrene was 22,000, and the molecular weight distribution (Mw / M
n) was found to be 1.05.

To an autoclave containing a reaction mixture containing the obtained polystyrene living polymer, 175 g of isoprene monomer distilled once in the presence of calcium hydride was added by a syringe with a needle under a nitrogen atmosphere.
Polymerization of isoprene was conducted at 5 ° C. for 5 hours. Next, a part of the reaction mixture was taken out, and the molecular weight was measured by GPC. The Mn (number average molecular weight) of the produced living polymer of polystyrene-b-polyisoprene was 45000, and the molecular weight distribution (Mw / Mn) was It turned out to be 1.03.

163 g of styrene monomer, which was distilled under reduced pressure twice in the presence of calcium hydride, was placed in an autoclave containing an obtained reaction mixture containing a living polymer of polystyrene-b-polyisoprene. And polymerization of styrene was carried out at 40 ° C. for 3 hours. Next, a part of the reaction mixture was taken out, and the molecular weight was measured by GPC. The obtained polystyrene-b-
Mn (number average molecular weight) of polyisoprene-b-polystyrene was 67000, and molecular weight distribution (Mw / Mn) was found to be 1.03. At this time, the unreacted monomer concentration of a part of the reaction mixture was measured by gas chromatography, and it was found that the polymerization rate was 99% or more.

In a 5 liter three-necked flask, tetrahydrofuran 1 distilled and purified in the presence of metallic sodium was added.
700 g was added and cooled to -78 ° C by immersion in a dry ice / methanol bath. In the flask, the polystyrene-b-polyisoprene-b- obtained above was added.
The reaction mixture containing the living polymer of polystyrene was pumped in a nitrogen atmosphere. Further, into this flask, 27 g of tert-butyl methacrylate monomer, which was distilled under reduced pressure twice in the presence of calcium hydride, was added dropwise using a syringe with a needle under a nitrogen atmosphere, and tert-butyl methacrylate was added for 3 hours.
Polymerization of t-butyl was performed. Then, 1 ml of methanol
Was dropped into the flask with a syringe with a needle to stop the polymerization. The unreacted monomer concentration was measured by subjecting a part of the reaction mixture to gas chromatography analysis, and it was found that the polymerization rate of tert-butyl methacrylate was 99% or more. The resulting reaction mixture was heated to room temperature, poured into 30 liters of methanol, and the precipitated polymer was collected by filtration under reduced pressure. The yield of the obtained polymer was 97%. The obtained polystyrene-b-polyisoprene-b-polystyrene-b-
Mn (number average molecular weight) of poly (tert-butyl methacrylate) was 71,000, and the molecular weight distribution (Mw / M
n) was found to be 1.05.

500 g of the recovered and dried polystyrene-b-polyisoprene-b-polystyrene-b-poly (tert-butyl methacrylate) was dissolved in 2200 g of reagent grade cyclohexane and placed in an autoclave having a volume of 5 liters. Using a complex of nickel octylate and triisobutylaluminum (molar ratio of nickel atom: aluminum atom: 1: 3.1) as a hydrogenation catalyst at a temperature of 60 to 80 ° C. and a hydrogen pressure of 10 kg / cm ² . The reaction was performed for 5 hours. The obtained reaction mixture was washed several times with dilute hydrochloric acid to remove the hydrogenation catalyst, and the obtained solution was poured into 15 liters of methanol to recover a precipitated polymer.

When the polymer (III-2) finally obtained was analyzed by ¹ H-NMR, the polymer was found to be polystyrene-b-hydrogenated polyisoprene-b-polystyrene-b-poly (methacrylic). Tert-butyl acid)
Of a poly (tert-butyl methacrylate) block (tert-butyl methacrylate).
Butyl unit content: 100 mol%) is 4.8.
% By weight, and as a polymer chain other than the block, M
n is 72000, molecular weight distribution (Mw / Mn) is 1.05
It was found to have a triblock copolymer chain of polystyrene-b-hydrogenated polyisoprene (hydrogenation ratio: 99%)-b-polystyrene (styrene unit content: 64% by weight).

Examples 1 and 2 and Comparative Example 1 Styrene resin (I), inorganic filler (II) and block copolymer (III-1) or (III-2) were prepared as shown in Table 1 below.
The mixture was melt-kneaded with a twin-screw extruder (resin temperature: 303 ° C. to 324 ° C.) and extruded to obtain a pellet-shaped thermoplastic resin composition. The obtained pellets were compression-molded at 280 ° C. and further annealed at 120 ° C. for 3 hours to produce test pieces. Table 1 also shows various measurement results using the test pieces.

[0063]

[Table 1]

From Table 1 above, the thermoplastic resin compositions obtained in Examples 1 and 2 according to the present invention are different from Comparative Example 1 in that they do not contain the block copolymer (III). It can be seen that the properties such as flexural strength and Izod impact strength of the obtained thermoplastic resin composition can be significantly improved while maintaining excellent properties such as flexural modulus and weight deflection temperature of the thermoplastic resin composition at a high level. In addition, it can be seen that the effect of improving the Izod impact strength is particularly large in the thermoplastic resin composition obtained in Example 2 according to the present invention. Further, in the thermoplastic resin compositions obtained in Examples 1 and 2 according to the present invention, compared with the thermoplastic resin composition obtained in Comparative Example 1 which is different from the present invention, after the hydrothermal treatment, It can be seen that the performance decrease was extremely small, and the water resistance was significantly improved.

[0065]

According to the present invention, when a styrene resin and an inorganic filler are mixed by heating, a specific block copolymer is blended in a specific ratio, thereby comprising the styrene resin and the inorganic filler. Provided is a thermoplastic resin composition having improved performance such as insufficient bending strength, impact resistance, and water resistance while maintaining the excellent performance of the thermoplastic resin composition at a high level. You. Further, according to the present invention, a simple method for producing a thermoplastic resin composition having such improved performance is provided.

Claims (2)

[Claims] (1) The following component (I) and the following component (II)
And a thermoplastic resin composition obtained by heating and mixing the following component (III): Component (I): styrene resin; Component (II): inorganic filler; Component (III): at least one weight It is composed of united blocks, and the content of the vinyl aromatic monomer unit is 50 to 10
0% by weight, a content of the conjugated diene unit which may be hydrogenated is 50 to 0% by weight, and a polymer chain (A) having a number average molecular weight of 20,000 to 200,000;
And a tertiary alkyl ester unit of methacrylic acid or acrylic acid having a polymer block (B) comprising a structural unit occupying 30 mol% or more, and the content of the polymer block (B) is 0.5 to (2) the weight ratio of component (I) to component (II) used is 30% by weight;
(I): Within the range of 98: 2 to 40:60 in (II); (3) The total weight of the components (III) and (II) is 100 parts by weight. For 0.1
A thermoplastic resin composition in the range of ２０20 parts by weight. 2. The following components (I) and (II)
And the following component (III) in a weight ratio of component (I) to component (II) of (I) :( II) of 98: 2 to 40:60.
And the weight of component (III) is less than component (I).
And 100 parts by weight of the total weight of the components and (II).
Component (I): styrenic resin; Component (II): inorganic filler; Component (III): at least one polymer block used in an amount of 1 to 20 parts by weight. And the content of the vinyl aromatic monomer unit is 50 to 10
0% by weight, a content of the conjugated diene unit which may be hydrogenated is 50 to 0% by weight, and a polymer chain (A) having a number average molecular weight of 20,000 to 200,000;
And a tertiary alkyl ester unit of methacrylic acid or acrylic acid having a polymer block (B) comprising a structural unit occupying 30 mol% or more, and the content of the polymer block (B) is 0.5 to (2) A method for producing a thermoplastic resin composition, comprising mixing the above-mentioned component (I), the above-mentioned component (II) and the above-mentioned component (III) by heating.