JPH1067893A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer compsn. which is excellent in rubber elasticity (compression set) and softness, has a good scratch resistance, and gives a molded item with a nonsticky surface. SOLUTION: This compsn. is prepd. by partly cross-linking a mixture comprising 20-80wt.% styrene block copolymer (A) comprising polymer blocks formed from styrene or its deriv. and polymer blocks formed from a coniugated diene, 80-20wt.% hydrocarbon-base rubber softener (B), 1-200 pts.wt. (based on 100 pts.wt. sum of ingredients A and B) propylene resin (C), and 0.3-10 pts.wt. (based on 100 pts. wt. sum of ingredients A and B) polysiloxane (D).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition having excellent rubber elasticity (compression set), excellent flexibility, good scratch resistance and no sticky surface.

[0002]

2. Description of the Related Art In recent years, the demand for thermoplastic elastomers has been increasing more than ever due to problems such as process rationalization and recycling. Among them, styrene-based thermoplastic elastomers mainly composed of hydrogenated styrene-based block copolymers are used for a wide range of applications because of their excellent flexibility and rubber elasticity (compression set). However, molded articles based on such elastomers are easily damaged and have a sticky surface, so it is necessary to paint in applications requiring designability that emphasizes appearance, such as interior and exterior parts of automobiles. there were.

Therefore, as an attempt to reduce the stickiness of the surface of a styrene-based thermoplastic elastomer, a method of adding a silicone oil (Japanese Patent Publication No. 6-74367,
JP-A-60-26508 and a method of partially cross-linking a styrene-based thermoplastic elastomer (Japanese Patent Publication No. 3-1).
No. 1291) has been proposed. However, even in these methods, enough to use without painting,
The reduction of the surface tackiness was not sufficient, and the improvement of the surface fragility was not achieved.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a thermoplastic resin which has the disadvantages of improving scratch resistance while maintaining the flexibility and rubber elastic properties of a styrenic thermoplastic elastomer and having no sticky surface. It is intended to provide an elastomer composition.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, added polysiloxane to a styrene-based thermoplastic elastomer, and furthermore, in the presence of peroxide. It has been found that by performing a dynamic heat treatment, the scratch resistance is good and the surface is no longer sticky, and the present invention has been completed. That is, the thermoplastic elastomer composition of the present invention is a thermoplastic elastomer composition obtained by subjecting a mixture comprising the following components (A) to (D) to a partial crosslinking treatment.

Component (A): A hydrogenated styrene block copolymer composed of a block (a) composed of a polymer of styrene or a derivative thereof and a block (b) composed of a copolymer of a diene copolymer 20 Component (B): Softener for hydrocarbon rubber 80 to 20% by weight Component (C): Propylene resin 1 to 100 parts by weight of the total amount of component (A) and component (B) 200% by weight Component (D): polysiloxane 0.3 to 10 parts by weight based on 100 parts by weight of the total of components (A) and (B).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

[I] Raw Materials (1) Compounding Material Component (A): Hydrogenated product of styrene-based block copolymer The hydrogenated product of styrene-based block copolymer is a block (a) composed of a polymer of styrene or a derivative thereof. When,
It is a hydrogenated product of a styrenic block copolymer composed of a block (b) composed of a conjugated diene polymer.

The monomer component of the polymer constituting the block (a) is styrene or a derivative thereof. Specific examples of the styrene derivative include α-methylstyrene, 1-vinylnaphthalene, and 2-vinylnaphthalene. , 3
-Methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene and the like. Among these, block (a)
Styrene, as a monomer component of the polymer constituting
α-Methylstyrene is preferred.

The polymer or copolymer constituting the block (b) is a homopolymer of butadiene, a homopolymer of isoprene or a copolymer of isoprene and butadiene, and is a copolymer of isoprene and butadiene. May be any of a random type, a block type and a tapered type. Specific examples of such a styrene-based block copolymer include a hydrogenated product of a styrene-butadiene-styrene block copolymer (hereinafter may be simply abbreviated as “hydrogenated SBS”), styrene. Hydrogenated isoprene / styrene block copolymer (hereinafter simply referred to as “hydrogenated SI-
S ". Or a hydrogenated product of a styrene-isoprene-butadiene-styrene block copolymer (hereinafter may be simply abbreviated as “hydrogenated S-BI-S”).

The proportion of the polymer block (a) composed of styrene or its derivative in the styrene block copolymer of the component (A) is preferably 5 to 50% by weight, more preferably 10 to 45% by weight in the copolymer. % By weight. That is, the ratio of the block (b) composed of the conjugated diene polymer block is in the range of 95 to 50% by weight, and more preferably 90 to 55% by weight.

In the present invention, a hydrogenated styrene block copolymer is used. It is important that the hydrogenation rate is 95% by weight or more, preferably 97 to 100% by weight. The styrenic block copolymer has a weight average molecular weight of 50,000 to 500,000.
0, preferably 60,000 to 450,000, particularly preferably 70,000 to 400,000.

Here, "weight average molecular weight" is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions. Calibration curves were determined using monodisperse polystyrene. (Conditions) Equipment: 150C ALC / GPC (MILLI
Column: Polystyrene mix gel column (AD80M)
/ S (manufactured by Showa Denko KK) Solvent: o-dichlorobenzene Temperature: 140 ° C Flow rate: 1 ml / min Injection volume: 200 μl Concentration: 2 mg / ml (antioxidant 2,6-di-t-butyl-p) -0.2% by weight of phenol was added, and the concentration was detected by F
Measured at a wavelength of 3.42 μm using an infrared spectrophotometer MIRAN1A manufactured by OXBORO. )

If the weight average molecular weight of the hydrogenated styrene block copolymer is more than 500,000, the moldability tends to be poor, and if it is less than 50,000, the rubber elasticity and mechanical strength tend to be poor. Become. As a method for producing a hydrogenated product of these styrenic block copolymers,
For example, a styrene-based block copolymer is synthesized from styrene and butadiene or isoprene in an inert solvent using a lithium catalyst by a method described in JP-B-40-23798. According to the methods described in JP-A Nos. 42-8704, JP-B-43-6636, JP-A-59-133203 and JP-A-60-79005, hydrogen is added in an inert solvent in the presence of a hydrogenation catalyst. Examples of the method include an addition method.

The hydrogenated S-BI-S is, for example, synthesized by the method described in JP-A-3-188114. Among these hydrogenated styrene-based block copolymers, the block (a) is a polymer block composed of styrene, and the conjugated diene polymer block of the block (b) is composed of isoprene alone or a mixture of isoprene and butadiene. Of the 1,2 bond represented by the following formula (I) in the isoprene polymer portion in the block (b) and the following formula (II)
A hydrogenated product of a styrenic block copolymer having a total of 3,4 bond content represented by the following formula of 40% or more of all isoprene bond units (hereinafter simply referred to as “hydrogenated vinylated SIS”).
May be abbreviated. ) Is preferable from the viewpoint of scratch resistance, and it is preferable to mix 5% by weight or more, preferably 7 to 90% by weight, particularly preferably 10 to 80% by weight of the whole component (A).

[0015]

## STR1 ## 1,2-bond (formula I)

[0016]

## STR2 ## 3,4-bond (formula II)

The hydrogenated vinylated SIS is synthesized, for example, by the method described in JP-A-2-102212 or JP-A-2-300218. Commercially available products include “Clayton G1651” manufactured by Shell Japan, “Septon 2006, 4055” and “High Blur HVS-3” manufactured by Kuraray, and “Toughtec H106” manufactured by Asahi Kasei Corporation.
1 "and" Dynalon 1320P "manufactured by Nippon Synthetic Rubber Co., Ltd.

Component (B): Softener for Hydrocarbon Rubber The softener for hydrocarbon rubber has a weight average molecular weight of 3
00 to 2,000, preferably 500 to 1,500. Such a softening agent for a hydrocarbon rubber is a mixture of an aromatic ring, a naphthene ring and a paraffin ring, wherein the number of carbon atoms in the paraffin chain accounts for 50% by weight or more of the total carbon. Is called “base oil” and contains 30 to 45% by weight of naphthenic ring carbon.
Is called naphthenic oil and has 3 aromatic carbon atoms.
Those with more than 0% by weight are classified as aromatic oils. Among them, it is preferable to use paraffin oil from the viewpoint of weather resistance.

The paraffinic oil used in the present invention has a kinematic viscosity at 40 ° C. of 20 to 800 cSt (centistokes), preferably 50 to 600 cSt, and a pour point of 0 to 600 cSt.
−40 ° C., preferably 0 to −30 ° C., and a flash point (C
OC) is from 200 to 400C, preferably from 250 to 350.
° C oil is preferably used. The hydrocarbon rubber softener is important for adjusting the hardness and the melt fluidity during molding.

Component (C): Propylene resin As the propylene resin used in the present invention, a propylene homopolymer and a copolymer resin containing propylene as a main component, specifically, propylene / ethylene random copolymer Examples thereof include a polymer and a propylene / ethylene block copolymer, and a propylene homopolymer is preferable.

The melt flow rate (JIS-K6
758, 230 ° C, 2.16 kg load) 0.01-1
00 g / 10 min, preferably 0.05 to 80 g / 10
Minute, particularly preferably 0.1 to 60 g / 10 min. Melt flow rate is 0.01g / 1
When a propylene-based resin for less than 0 minutes is used, molding, especially injection moldability, is deteriorated, and the appearance of the obtained injection-molded article, particularly, occurrence of flow marks becomes extremely large. Also,
If the melt flow rate exceeds 100 g / 10 minutes, the material strength tends to decrease.

Component (D): Polysiloxane The polysiloxane used in the present invention has a kinematic viscosity at 25 ° C. of 10 to 10,000 cSt (centistokes), preferably 100 to 5,000 cSt, particularly preferably 500 to 3,000 cSt. 000 cSt, pour point of -65 ° C or less, preferably -50 ° C or less, and flash point (COC)
However, oils having a specific gravity of 0.7 to 1.2, preferably 0.9 to 1.1 are preferably used at 150 ° C or higher, preferably 310 ° C or higher, particularly preferably 315 ° C or higher, and 25 ° C.

Among them, polyorganosiloxane is preferable, and specific examples thereof include polydimethylsiloxane, polymethylphenylsiloxane, polydimethyl-diphenylsiloxane and the like, and a mixture of two or more of these may be used. Among these, polydimethylsiloxane is particularly preferred. When a polysiloxane having a kinematic viscosity at 25 ° C. of less than 10 cSt is used, both the sticky improving effect and the scratch improving effect of the molded article tend to decrease. When a kinematic viscosity at 25 ° C. of more than 10,000 cSt is used, the melt fluidity tends to decrease, and the appearance of the injection molded article tends to deteriorate.

(2) Additional compounding materials (optional components) In addition to the above components (A) to (D), the thermoplastic elastomer composition of the present invention may contain optional compounding components according to various purposes. can do. Specifically, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, anti-fog agents, anti-blocking agents, slip agents, crosslinking agents, crosslinking assistants, coloring agents, flame retardants And various additives such as a dispersant and an antistatic agent.

Further, as long as the effects of the present invention are not remarkably impaired, various thermoplastic resins other than the above-mentioned propylene-based resin, various elastomers other than the above-mentioned styrene-based block copolymer, various plasticizers, various fillers, etc. Blending materials can be blended. Various thermoplastic resins include low density polyethylene (branched ethylene polymer), medium density,
Ethylene polymers such as high-density polyethylene (linear ethylene polymer) and ethylene and unsaturated compounds such as ethylene-unsaturated carboxylic acid copolymers or anhydrides thereof (acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid) Olefin resins such as copolymers of acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, norbornene-5,6-dicarboxylic acid, and anhydrides thereof; styrene homopolymer, acrylonitrile / styrene resin, acrylic Styrene resins such as nitrile / butadiene / styrene resins; polyphenylene ether resins and the like.

The various elastomers have rubber elasticity other than the hydrogenated product of the styrene / conjugated diene block copolymer described in the component (A), and specifically include polybutadiene, polyisoprene, and polyisobutylene. Homopolymers of olefins such as ethylene; propylene copolymer rubber (EPM);
Ethylene propylene / non-conjugated diene copolymer rubber (EPDM) using ethylidene-2-norbornene, 5-methylenenorbornene, 5-vinylnorbornene, dicyclopentadiene, 1,4-hexadiene, etc., ethylene / butene copolymer Olefin copolymer rubbers such as rubber (EBM), ethylene-octene copolymer rubber, ethylene-propylene-butene copolymer rubber; ethylene-butadiene copolymer, ethylene-isoprene copolymer, ethylene-chloroprene copolymer Copolymers of ethylene and diene such as copolymers; copolymers of ethylene and organic acid esters such as ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, etc. A copolymer of acrylic acid ester and a small amount of monomer for crosslinking (A M), acrylic acid ester - acrylic rubbers such as acrylonitrile polymer rubber (ANM),
Acrylic polymer rubber such as acrylate-butadiene copolymer rubber, ethylene-acryl rubber (AEM); natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber Butyl rubber; nitrile rubber; chloroprene rubber; silicone rubber; fluoro rubber; urethane rubber; polyurethane elastomer; polyamide elastomer; polyester elastomer such as polyester polyether block copolymer and polyester polyester block copolymer. A chlorine-based soft resin such as a soft vinyl chloride resin or a chlorinated polyethylene; an olefin-based thermoplastic elastomer containing the above-described olefin-based copolymer rubber; Run ", Mitsui Petrochemical Industries Co., Ltd." MILASTOMER ", manufactured by Sumitomo Chemical Co., Ltd." Sumitomo TPE ", A
"Santoprene" manufactured by ES Company and the like can be mentioned.

The components (E) to (F) described below are preferred among the above-mentioned additional components. Component (E): Inorganic filler As the inorganic filler used as an additional component in the thermoplastic elastomer composition of the present invention, talc, mica, glass fiber, whisker, carbon fiber, calcium carbonate, titanium oxide, carbon black, glass Balloon, clay, magnesium carbonate, barium sulfate, glass or metal powder and the like can be mentioned.

Among them, it is preferable to use a plate-like inorganic filler such as talc and mica, and calcium carbonate from the viewpoint of balance of physical properties. Particularly preferred talc has an average particle size of 20 μm or less, and preferably has a length of substantially 15 μm.
m, particularly preferably those having an average aspect ratio of 5 or more.

Here, the talc length is “substantially”
Most talc particles are in this range. The talc is produced, for example, by crushing raw talc with an impact crusher or a micro-type crusher, finely crushing with a micron mill or a jet-type crusher, and then classifying and adjusting it with a cyclone or a micron separator.

Here, the measurement of the average particle size is performed by using a laser
It is a value measured using a random particle size distribution meter.
Examples of a suitable measuring device include LA-500 manufactured by Horiba, Ltd.
A mold is desirable because of its excellent measurement accuracy. Also, the diameter,
The length and aspect ratio are values measured with a microscope.
You. Further, as a preferable calcium carbonate, specific surface area
Is 40,000cm^Two/ G or less, preferably 30,00
0cm^Two/ G or less, particularly preferably 5,000 cm ^Two/
g ~ 30,000cm^Two/ G, and the average particle size is
Generally 0.5 to 20.0 μm, preferably 1.0 to 2.
5 μm.

This inorganic filler is used in an amount of 1 to 100 parts by weight, preferably 2 to 75 parts by weight, more preferably 3 to 6 parts by weight, based on 100 parts by weight of the total of the components (A) and (B).
It is preferable to add 0 parts by weight. The addition of the inorganic filler has the purpose of adjusting the hardness, density, and gloss of the molded product, and has the effect of reducing the surface stickiness.

Component (F): Fatty acid amide and / or fatty acid metal salt Examples of the fatty acid amide used as an additional component in the thermoplastic elastomer composition of the present invention include lauric amide, palmitic amide, atearic amide, and behenin. Saturated fatty acid amides such as acid amide, oleic acid amide, stearic acid amide, erucic acid amide,
Unsaturated fatty acid amides such as behenamide, bis fatty acid amides such as methylene bis oleic acid amide, methylene bis stearic acid amide, ethylene bis oleic acid amide, ethylene bis stearic acid amide, etc. Examples of the fatty acid metal salt include lithium stearate, calcium stearate, zinc stearate and the like.

Preferred fatty acid amides have a melting point of 5
0 to 200 ° C, preferably 60 to 150 ° C, and an average molecular weight of 100 to 1,000, preferably 200 to 800. Among them, the general formula: R ₁ R ₂ N-CO-R
₃ (wherein R ₁ and R ₂ are each independently hydrogen or an alkyl group having 1 to ₃ carbon atoms, and R ₃ is an alkyl group having 15 to 30 carbon atoms).

Preferred fatty acid metal salts have a melting point of 5
0-300 ° C, preferably 60-200 ° C, with a molecular weight of 1
00～1,000, preferably of 200 to 800, among the general _{formula: (R 4 -CO-O-)} n-
M (R ₄ is an alkyl group having 15 to 30 carbon atoms, M is Ia
To IIIa, and n is an integer equal to the valence number of the metal M).

This fatty acid amide and / or metal salt of fatty acid is used in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, based on 100 parts by weight of the total of components (A) and (B). And more preferably 0.3 to 5 parts by weight. The incorporation of the fatty acid amide and / or fatty acid metal salt has the purpose of improving the releasability at the time of molding, especially at the time of injection molding, and reducing the amount of polymer (the phenomenon that the polymer accumulates around the extrusion die over time) during extrusion molding. In addition, there is also an effect of reducing stickiness on the surface of the molded product.

(3) Mixing ratio The mixing ratio of each component constituting the thermoplastic elastomer composition of the present invention is such that component (A) is 20 to 80% by weight of the total amount of component (A) and component (B). , Preferably 25 to 75
%, Particularly preferably 30 to 70% by weight. If the component (A) is less than 20% by weight, the mechanical strength is poor, and if it exceeds 80% by weight, the flexibility and moldability are poor.

On the other hand, the mixing ratio of the component (B) is from 80 to 20% by weight, preferably from 75 to 25% by weight, and particularly preferably from 70 to 25% by weight of the total amount of the components (A) and (B).
３０30% by weight. When the mixing ratio of the component (B) is 80
If the amount is more than 10% by weight, the mechanical strength is inferior, and if it is less than 10%, the flexibility and moldability are inferior.

The mixing ratio of the component (C) is 1 to 100 parts by weight of the total amount of the components (A) and (B).
The amount is 200 parts by weight, preferably 3 to 150 parts by weight, particularly preferably 5 to 100 parts by weight. When the proportion of the component (C) exceeds 200 parts by weight, the flexibility and rubber elasticity (compression set) of the thermoplastic elastomer composition are poor.
If the amount is less than the weight part, the mechanical strength, heat resistance and oil resistance are inferior.

Further, the mixing ratio of the component (D) is 0.1 part by weight based on 100 parts by weight of the total amount of the components (A) and (B).
It is 3 to 10 parts by weight, preferably 0.5 to 8 parts by weight, particularly preferably 0.7 to 6 parts by weight. If the proportion of the component (D) exceeds 10 parts by weight, the appearance of the obtained molded article is inferior, and if it is less than 0.3 part by weight, the molded article surface is inferior in scratch resistance and the surface is sticky. It will be.

(4) Partial Cross-linking Treatment There are various methods for obtaining the partially cross-linked thermoplastic elastomer composition of the present invention. The components (A) to (D) are uniformly mixed with the additives described in the section of the additional compounding materials, if necessary, using a Henschel mixer, a ribbon blender, a V-type blender or the like within the above-mentioned mixing ratio. And then mix the mixture with a Banbury mixer,
Using a conventional kneader such as a kneader, a roll, or a multi-screw kneading extruder such as a single-screw or twin-screw, the method of melting and kneading simultaneously and dynamically heat-treating in the presence of a peroxide as a crosslinking agent is simple and efficient. Is preferred. When heat-treating dynamically, you may use together a crosslinking aid and an antioxidant as needed.

It is important that the thermoplastic elastomer composition of the present invention is subjected to a partial cross-linking treatment step such as a dynamic heat treatment in the presence of a peroxide. Regardless of the degree of cross-linking of the elastomer composition, the molded article surface has good scratch resistance and no stickiness on the surface. The peroxide used may be either aromatic or aliphatic, and may be a single peroxide or a mixture of two or more peroxides. Specifically, 2,5
-Dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (ter
t-butylperoxy) hexyne-3, tert-butylperoxybenzoate, dicumyl peroxide,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane, tert-butylcumyl peroxide,
Diisopropyl benzohydroperoxide, benzoyl peroxide and the like are used.

Examples of the crosslinking aid which may be used in combination with the above-mentioned peroxide include auryl polyfunctional monomers such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate and the like. There are benzene, liquid polybutadiene and the like. In addition, as an antioxidant,
For example, monophenolic compounds, bis, tri- or polyphenolic compounds, thiobisphenolic compounds and phenolic compounds composed of polyhydric phenols or derivatives thereof, or naphthylamine compounds,
Examples thereof include amine compounds including a diphenylamine compound and a p-phenylenediamine compound.

Compounds belonging to the above-mentioned monophenol compounds include 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol,
4-dimethyl-6-tert-butylphenol, 2,
4,6-tri-tert-butylphenol and the like.
In the above bis, tri or polyphenol compounds,
4,4-dihydroxydiphenyl, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), tris (2-methyl-4-hydroxy-5-te
rt-butylphenyl) butane and tetrakis [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane.

The thiobisphenol-based compounds include:
4,4'-thiobis (6-tert-butyl-3-methylphenol), 2,2'-thiobis (6-tert-
Butyl-4-methylphenol) and the like. The polyhydric phenol or a derivative thereof includes di-tert-butylhydroquinone and the like.

The above naphthylamine compounds include phenyl-α-naphthylamine. Examples of the diphenylamine-based compound include p-isoproxydiphenylamine. The p-phenylenediamine-based compound includes N, N'-diphenyl-p-phenylenediamine,
N, N'-di-2-naphthyl-p-phenylenediamine and the like.

Among the above-mentioned compounds (a) to (d), the phenolic antioxidants are preferred. The amounts of peroxide, crosslinking aid and antioxidant used are
The peroxide is generally 0.1 to 3 parts by weight (preferably 0.1 to 100 parts by weight) with respect to 100 parts by weight of the mixture comprising the components (A) to (D).
To 1 part by weight) Crosslinking aid: 5 parts by weight or less (preferably 0.1 to 5 parts by weight, particularly preferably 0.1 to 3 parts by weight) Antioxidant: 3 parts by weight or less (preferably 1 part by weight or less) ). In general, the amount of the crosslinking aid is preferably set to about 1 to 3 times the molar ratio of peroxide.

If the amount of the peroxide is less than 0.1 part by weight, the molded article based on the elastomer composition obtained has poor scratch resistance. If the amount is more than 3 parts by weight, the moldability deteriorates and the mechanical strength and elongation decrease. The temperature of melt kneading (dynamic heat treatment) is 100 ° C
To 400 ° C, preferably 150 ° C to 300 ° C, particularly preferably 180 ° C to 280 ° C.
The processing time is 10 seconds to 30 minutes, preferably 20 seconds to 20 minutes.

(5) Composition The thermoplastic elastomer composition of the present invention obtained by subjecting the above raw materials to dynamic heat treatment has an A hardness in the range of 20 to 95 according to JIS-K6301. Depending on the product, 30-90 for products that require flexibility
Are preferable, and those of 35 to 85 are particularly preferable. In general, those having a JIS-A hardness of less than 20 are inferior in moldability (releasability), and those having a JIS-A hardness of more than 90 tend to be inferior in rubber elasticity, which is not preferable.

[II] Molded Article The molded article of the thermoplastic elastomer composition of the present invention can be produced by extrusion molding, blow molding, rotational molding, press molding, injection molding (insert injection molding,
Various molding methods such as two-color injection molding, core back injection molding, sandwich injection molding, and injection press molding can be used. Especially injection molding,
Extrusion molding is preferred.

In general, conditions for injection molding are as follows.
Molding temperature of 00 to 300 ° C, preferably 150 to 280 ° C, particularly preferably 200 to 260 ° C;
0 kg / cm ² , preferably 100 to 800 kg / cm
Molded at an injection pressure of ² . Further, molded parts other than products such as runners and spools, defective molded products, and the like can be recycled and used.

[III] Use The molded article made of the thermoplastic composition of the present invention can be used as various industrial parts. Specifically, automotive interior parts such as instrument panels, center panels, center console boxes, door trims, pillars, assist grips, handles, airbag covers; automotive exterior parts such as bumpers and moldings; rack and pinion boots, suspension boots Parts for automobiles, such as boots and constant velocity joint boots; Home appliance parts such as vacuum cleaner bumpers, remote control switches, various rolls and key tops for OA equipment; Underwater products such as underwater glasses and underwater camera covers; Various cover parts; Industrial parts with various packings for the purpose of waterproofing, soundproofing, vibration-proofing, etc .; Electrical and electronic parts such as curled cord wire covering, belts, hoses, tubes, sound deadening gears; and sports equipment etc. it can.

[0052]

The present invention will be described more specifically with reference to the following examples. [I] Evaluation method Various evaluations in these Examples and Comparative Examples were performed by the following test methods. However, the measurement samples (1) to (5) were subjected to an injection pressure of 500 kg / cm ² , an injection temperature of 240 ° C., and a mold temperature of 40 using an in-line screw type injection molding machine (a small injection molding machine manufactured by Toshiba Machine Co .; IS90B).
120mm long, 120mm wide, 3m thick molded at ℃
m obtained by transverse punching of square sheets.

(1) JIS-A hardness [-] Complies with JIS-K-6301 (2) Compression set [%] Complies with JIS-K-6301 Compression set (70 ° C. × 22) Time) was measured. (3) MFR [g / 10 min] According to JIS-K-7210 MFR [230 ° C; 2.16 kg] as a measure of moldability
Was measured. (4) Stickiness of the surface After leaving the above injection molded sheet at 23 ° C. for 2 days, five panelists evaluated it with tentacles. And (5) Scratch resistance (pencil scratch hardness test) After leaving the above injection molded sheet at 23 ° C for 2 days, JIS
-K-5401 pencil scratch hardness test (20
(A pencil with a 0 g load and H hardness) was used to confirm the surface scratch resistance. When the scratch was conspicuous, X was given; when the scratch was a little noticeable;

[II] Raw Material Component (A): Hydrogenated product of styrene / conjugated diene block copolymer

[0055]

[Table 1]

Component (B): Softener for hydrocarbon rubber

[0057]

[Table 2]

Component (C): Propylene resin

[0059]

[Table 3]

Component (D): polysiloxane

[0061]

[Table 4]

Component (E): inorganic filler

[0063]

[Table 5]

Component (F): fatty acid amide and / or metal salt of fatty acid

[0065]

[Table 6]

[III] Experimental Examples and Comparative Examples Examples 1 to 19 and Comparative Examples 5 to 10 First, the components (A), (B) and ( D) was mixed with a Henschel mixer, and then, based on 100 parts by weight of the remaining components and the total composition shown in Tables 7 to 9, 2,5-dimethyl-2,5-di (t) as a peroxide 0.1 parts by weight of -butylperoxy) hexane-3, 0.2 parts by weight of divinylbenzene as a crosslinking aid, and a phenolic antioxidant (trade name "Irganox 101" manufactured by Ciba-Gaiky)
0 ") 0.1 part by weight is added and mixed. Next, melt kneading and dynamic heat treatment were performed at 220 ° C. for 30 seconds with a twin screw extruder having a compression ratio (L / D) of 33 and a cylinder diameter of 45 mm to obtain pellets of a thermoplastic elastomer composition. . These evaluation results are shown in Tables 7-9.

Comparative Examples 1 to 4 In the composition (parts by weight) shown in Table 9, first, the component (A)
The component (B) and the component (D) were mixed with a Henschel mixer, and then the phenolic antioxidant (trade name, manufactured by Ciba-Gaiky Co., Ltd.) was added to the remaining components and 100 parts by weight of the total composition shown in Table 9. "Irganox 1010")
Add 0.1 part by weight and mix. Next, the compression ratio (L /
D) = 2 with a twin screw extruder with a cylinder diameter of 45 mm
Melt kneading was performed for 30 seconds at a setting of 20 ° C. to obtain pellets of the thermoplastic elastomer composition. Table 9 shows the results of these evaluations.

[0068]

[Table 7]

[0069]

[Table 8]

[0070]

[Table 9]

[0071]

Industrial Applicability The thermoplastic elastomer composition according to the present invention has disadvantages such as scratch resistance and stickiness of a molded product without impairing the advantages of rubber elasticity (compression set) and flexibility of a styrene-based elastomer. It has excellent appearance and tactile sensation without coating the surface of the molded body, and has a wide range of application as a base material for automobile interior and exterior members.

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Claims (3)

[Claims] 1. A thermoplastic elastomer composition obtained by subjecting a mixture comprising the following components (A) to (D) to a partial crosslinking treatment. Component (A): a hydrogenated product of a styrene block copolymer composed of a block (a) composed of a polymer of styrene or a derivative thereof and a block (b) composed of a copolymer of a diene; % Component (B): Softener for hydrocarbon rubber 80 to 20% by weight Component (C): Propylene resin 1 to 200 parts by weight with respect to 100 parts by weight of the total of components (A) and (B). Component (D): polysiloxane 0.3 to 10 parts by weight based on 100 parts by weight of the total of components (A) and (B). 2. Component (A) wherein the block (a) is a polymer block composed of styrene, and the conjugated diene polymer block of the block (b) is a polymer composed of isoprene alone or a mixture of isoprene and butadiene. Hydrogenation of a styrenic block copolymer in which the total of 1,2 bond content and 3,4 bond content in the isoprene polymer portion in the block (b) is 40% or more of all isoprene binding units The product is added to 5 of the whole component (A).
The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition is contained in an amount of at least% by weight. 3. The thermoplastic elastomer composition further comprises at least one of the following components (E) to (G): a hydrogenated product of a styrene block copolymer of component (A) and a component (B). The thermoplastic elastomer composition according to claim 1 or 2, wherein the thermoplastic elastomer composition is blended in the following ratio with respect to a total of 100 parts by weight of the softening agent. Component (E): 1 to 100 parts by weight of inorganic filler Component (G): 0.1 to 10 parts by weight of fatty acid amide and / or metal salt of fatty acid