JPH10130452A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic elastomer compsn. which is excellent in rubber elasticity, resistances to heat and weather, moldability, softness, and clarity and hardly exhibits softener bleeding by compounding a hydrogenation product of a block copolymer comprising monovinylarom. hydrocarbon polymer blocks having a high 1,2-vinyl bond content and butadiene polymer blocks with a crystalline olefin polymer and if necessary a softener. SOLUTION: This compsn. is prepd. is prepd. by compounding 100 pts.wt. hydrogenation product of a copolymer represented by the formula: A-(B-A)n and/or (A-B)n (wherein A is a monovinylarom. hydrocarbon polymer block; B is a conjugated diene polymer block having a 1,2-vinyl bond content of 55-90%; and n is an integer of 1-5) with 3-350 pts.wt. crystalline olefin polymer (pref. a propylene polymer) and 0-250 pts.wt. hydrocarbon-base rubber softener.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to flexibility, rubber elasticity,
The present invention relates to a thermoplastic elastomer composition having excellent weather resistance, transparency, and moldability, and having little bleeding of a softener. This elastomer composition is used for food, daily necessities, toys / exercise equipment, stationery such as desk mats, interior / exterior automobiles, civil engineering / architectural applications such as civil engineering sheets and waterproof sheets, AV / home appliances, OA・ Office equipment use, clothing and footwear use, textile use, medical equipment use such as various catheters, sanitary goods such as disposable diapers and sanitary goods, chemical and mining and industrial materials, packaging and transportation materials, agricultural and livestock and fishery materials, etc. Available in the field.

[0002]

2. Description of the Related Art In recent years, thermoplastic elastomers (hereinafter abbreviated as TPEs), which are rubber-like soft materials and do not require a vulcanization process and have the same moldability as thermoplastic resins, have been developed.
It is attracting attention and used in the fields of automobile parts, home appliance parts, medical and food equipment parts, electric wires, miscellaneous goods and the like. At present, various types of polymers such as polyolefins, polyurethanes, polyesters, and polystyrenes have been developed and commercially available for such TPEs.

However, these TPEs have not reached the level of vulcanized rubber in terms of quality, especially softness, in the use of vulcanized rubber, which is one of the wide fields of application as rubber. The use in the conventional vulcanized rubber field is extremely limited. For example, polyolefin-based TPEs are relatively inexpensive and have excellent heat resistance and weather resistance, but cannot obtain soft ones. Even the most flexible ones have a JIS-A hardness (JI
SK-6301), which is about 70, and lacks a soft feeling compared to JIS-A hardness 60 of general vulcanized rubber. Polyester-based TPE and polyurethane-based TPE also have the JIS-A hardness of 70 to 90 even among the most flexible ones among commercially available products.
It is very hard compared to vulcanized rubber, and is not suitable for the application field of vulcanized rubber.

On the other hand, a polymer having a styrene block-butadiene block-styrene block portion (SBS)
And polystyrene-based TPEs such as polymers having a styrene block-isoprene block-styrene block (SIS) are more flexible and have better rubber elasticity than the above-mentioned polyolefin-based TPE, polyester-based TPE and polyurethane-based TPE. Has a double bond in the polybutadiene block or polyisoprene block in the polymer, so it has heat aging resistance (thermal stability)
And there is a problem in weather resistance. Japanese Patent Application Laid-Open No. 50-82162 discloses that polyester based elastomers such as SBS and SIS
Is proposed to utilize the merits of both, but this composition did not have sufficient performances such as ozone resistance and thermal stability.

Elastomers having improved thermal stability by hydrogenating intramolecular double bonds of a copolymer having a styrene block portion and a conjugated diene block portion (SEBS)
And SEPS) are well known, and JP-A-3-100045 discloses a JIS-A hardness in which 25 to 185 parts by weight of a polyester thermoplastic elastomer is blended with 100 parts by weight of a hydrogenated SBS. Is 35
Japanese Patent Publication No. 5-75016 discloses a laminate of a skin material having a hardness of 70 to 75 degrees and a resin core material layer having a hardness of 70 degrees or more.
100 parts by weight of hydrogenated S and SIS
It has been proposed that a composition containing 0 to 200 parts by weight of an oil and 0 to 150 parts by weight of a polyolefin resin and (b) a composition containing 5 to 100 parts by weight of a polyester elastomer be used as a skin material if necessary. I have.

However, in the examples of these publications, the JIS-A hardness of the skin material is 62 or more. JIS-A hardness 3
In order to obtain a TPE molded body having a low hardness of 0 or less, a large amount of a hydrocarbon-based softening agent (oil) must be blended or the blending amount of a propylene-based resin must be reduced. Or poor moldability).

Further, it is inferior in transparency and cannot be used in fields requiring transparency such as silicone rubber replacement. JI
As a skin material with SA hardness of 30 degrees or less, Japanese Patent Publication No. 4-24
No. 12 discloses that a) at least two polymer blocks A mainly composed of a vinyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound having a 1,2-microstructure of 20 to 50%. B is hydrogenated to obtain a block copolymer having a block A content of 5 to 60% by weight, a block B content of 95 to 40% by weight, and a vinyl aromatic in the block A. A compound, a hydrogenated conjugated diene compound in block B in an amount of more than 50% by weight, and a hydrogenated block copolymer elastomer (skin material); b) a polyolefin resin, a polystyrene resin, ABS We propose a multilayer injection-molded product obtained by molding a resin (core material) selected from resins by a two-color injection molding method. However, the molding temperature range of the skin material layer is narrow,
It is necessary to mix a large amount of paraffin oil in order to have a poor appearance and to strengthen the fusion force of the core material with polypropylene (Example 2 of the publication), and the skin material layer becomes sticky,
Poor releasability.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the bleeding of the softening agent without impairing the physical properties such as excellent rubber elasticity, weather resistance and molding workability of the thermoplastic elastomer (the surface of the molded article is not affected). An object of the present invention is to provide a thermoplastic elastomer composition having excellent translucency, which is free from stickiness, has a high flexibility, and has a haze (haze value) (JIS-K7105) of 60% or less, preferably 10 to 40%.

[0009]

The inventor of the present invention has conducted various studies to solve the above-mentioned problems, and as a result, has found a high 1,2-value.
Compounded with a hydrogenated product of a block copolymer consisting of a monovinyl-substituted aromatic hydrocarbon polymer block and a butadiene polymer block having a vinyl bond amount, combined with a crystalline olefin polymer and, if necessary, a softener for hydrocarbon rubber. By doing so, the rubber elasticity, heat resistance, weather resistance, excellent moldability, and less bleeding of the softener, found that it is particularly excellent in flexibility and transparency, has led to the completion of the present invention. is there. That is, the present invention provides (a)
General formula

[0010]

A- (BA) n and / or (AB) n

[Wherein A is a polymer block of a monovinyl-substituted aromatic hydrocarbon, B is a conjugated diene polymer block having a 1,2-vinyl bond ratio of 55 to 90%, and n is 1
Is an integer of up to 5. (B) 3 to 350 parts by weight of the crystalline olefin polymer and (c) 0 to 250 parts by weight of the hydrocarbon rubber softener based on 100 parts by weight of the hydrogenated product of the block copolymer represented by the formula An object of the present invention is to provide a thermoplastic elastomer composition characterized by being blended in parts by weight.

[0012]

By using a block copolymer having a conjugated diene polymer block portion having a high 1,2-vinyl bond ratio of 55 to 90% as the polystyrene elastomer of the component (a), excellent flexibility is obtained. Sticky TP
Give an E molded body.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (a) Hydrogenated product of polystyrene-based block copolymer:
The hydrogenated product of the polystyrene-based block copolymer used as the component (a) in the present invention has the general formula A- (BA)
n and / or (AB) n wherein A is a monovinyl-substituted aromatic hydrocarbon polymer block, B is a conjugated diene polymer block having a 1,2-vinyl bond ratio of 55 to 90%, n is an integer of 1 to 5. ] Is a hydrogenated product of the block copolymer represented by the formula:

The polymer component constituting the block (A) of the hydrogenated product of the polystyrene block copolymer is a polymer of styrene or a derivative thereof. Specific examples of the styrene derivative include α-methylstyrene and 1-methylstyrene.
Vinyl naphthalene, 2-vinyl naphthalene, 3-methyl styrene, 4-propyl styrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzyl styrene, 4- (phenyl butyl) styrene and the like can be mentioned. Among them, the polymer component constituting the block (A) is preferably a styrene polymer, an α-methylstyrene polymer, or a copolymer of styrene and α-methylstyrene.

The polymer block (B) is a conjugated diene polymer block. As conjugated dienes, butadiene,
One or more of isoprene, 1,3-pentadiene and the like are selected, and among them, butadiene alone or a mixture of butadiene and isoprene is preferred. The 1,2-vinyl bond content of the conjugated diene portion is desirably 55 to 90%, preferably 60 to 85%, and more preferably 60 to 80%. If it is less than 55%, the resulting thermoplastic elastomer molded article is unlikely to exhibit the effects of improving flexibility and transparency. On the other hand, if it exceeds 90%, it exhibits a crystal structure and becomes resinous due to hydrogenation, resulting in poor flexibility, which is not preferable. Here, the vinyl bond position of the polymer block (B) of the conjugated diene of the block copolymer will be described below, using butadiene and isoprene as examples of the conjugated diene.

[0016]

Embedded image

When the aromatic compound (A) is styrene and the conjugated diene (B) is butadiene, the NMR of the block copolymer after hydrogenation was measured. C. Rand
allJ. Polym. Sci. , Polym. Ph
s. Ed. Vol. 13,901 (1975), the signals were assigned, and the amount of 1,2-vinyl bond was determined. The proportion of the polymer block (A) in the copolymer of the component (a) is 5 to 45% by weight, preferably 10 to 40% by weight. When the proportion occupied by the polymer block (A) is less than 5% by weight, the mechanical strength and rubber elasticity of the obtained TPE molded article are inferior. When the proportion of the polymer block (A) exceeds 45% by weight, the obtained TPE
The flexibility and rubber elasticity of the molded article are inferior, and the bleeding of the softening agent is deteriorated.

The weight average molecular weight of the hydrogenated block copolymer (a) is from 100,000 to 500,000, preferably from 3 to 45.
And more preferably in the range of 50,000 to 400,000. When the weight average molecular weight is less than 10,000, the rubber elasticity of the obtained TPE molded article is inferior. On the other hand, when it exceeds 500,000, the viscosity is high, the melt fluidity of the thermoplastic elastomer composition is poor, and the moldability is poor. The molecular structure of the hydrogenated block copolymer (a) may be linear, branched, radial, or any combination thereof.

Here, the "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. Equipment: 150C ALC / GPC (MILLIPOR
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-4-methylphenol was added in an amount of 0.2% by weight, and the concentration was detected by an infrared spectrophotometer MIRAN manufactured by FOXBORO.
1A at a wavelength of 3.42 μm).

As a method for producing the polystyrene block copolymer, any known production method may be used as long as the above-mentioned structure can be obtained. For example,
According to the method described in Japanese Patent No. 23798, styrene, then conjugated diene and styrene can be obtained by block polymerization in an inert solvent using a lithium catalyst or the like.

The hydrogenation treatment of these block copolymers is described in, for example, JP-B-42-8704 and JP-B-43-870.
According to the method described in JP-A-6636 or JP-A-59-133203 and JP-A-60-79005, hydrogenation is carried out by heating in an inert solvent in the presence of a hydrogenation catalyst. In this hydrogenation, at least 50 olefinic double bonds in the polymer block (B) are added.
%, Preferably 80% or more is hydrogenated, and 25% or less of the aromatic unsaturated bond in the polymer block (A) is hydrogenated. The hydrogenated block copolymer of the component (a) imparts flexibility and rubber elasticity to the TPE molded article.

(B) Crystalline olefin polymer: (b)
As the crystalline olefin polymer of the component, an olefin homopolymer or copolymer having a crystallinity of 20 to 75% can be used, and its melting peak temperature measured by a differential calorimeter (DSC) is 130 ° C. Those having a melt flow rate of less than 190 ° C are those having a melt flow rate of less than 130 ° C (JIS-K7210, 2.
16 kg load) is 0.01 to 100 g / 10 min, preferably 0.05 to 80 g / 10 min, particularly preferably 0.1 to 100 g / 10 min.
Ｇ60 g / 10 min, and the flexural modulus (JIS-K7
213) is 500 kg / cm ² or more, preferably 1,0
00 to 40,000 kg / cm ² , more preferably 3,
000-15,000 kg / cm ² is used. Specific examples include a crystalline ethylene polymer, a propylene polymer, polybutene-1 and poly-4-methylpentene-1 and the like. Preferred examples of the crystalline olefin polymer include an ethylene polymer and a propylene polymer. A polymer, particularly preferably a propylene-based polymer.

Examples of the ethylene polymer include high-density, linear or branched medium-density or low-density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 Copolymer, ethylene / heptene-1 copolymer, ethylene / octene-
1 copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid alkyl ester copolymer, ethylene / methacrylic acid copolymer , Ethylene / methacrylic acid alkyl ester copolymer, and the like.
945 to 0.970 g / cm ³ of high density polyethylene,
A linear or branched medium density and low density polyethylene having a density of 0.890~0.945g / cm ^3.

As the propylene-based polymer, a propylene homopolymer or a copolymer of propylene as a main component and an α-olefin having 2 to 10 carbon atoms is used. A polypropylene synthesized using a catalyst or a Kaminski type catalyst, or a random or block polypropylene copolymer is used.

Examples of the α-olefin in the copolymer include ethylene, butene-1, hexene-1, octene-1, and the like. The proportion of these α-olefins is 30% by weight.
The following are used: Specifically, propylene homopolymer, propylene / ethylene copolymer, propylene /
Ethylene-butene-1 copolymer, propylene-4-methylpentene-1 copolymer and the like. The crystalline olefin polymer of the component (b) improves the moldability of the thermoplastic elastomer composition and contributes to the shape retention and heat resistance of the TPE molded article.

(C) Softener for Hydrocarbon Rubber: The softener for hydrocarbon rubber as the component (c) has a weight average molecular weight of 300 to 2,000, preferably 500 to 1,500.
Are used, and mineral oil-based hydrocarbons or synthetic resin-based hydrocarbons are preferred. A mineral oil-based softener is a mixture of an aromatic ring, a naphthene ring, and a paraffin chain, and a mixture in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total carbon is called a paraffin oil. Those having a naphthene ring carbon number of 30 to 45% are called naphthenic oils, and those having an aromatic carbon number of 35% or more are called aromatic oils. Of these, paraffinic oils are preferred as rubber softeners.

The paraffinic oil has a kinematic viscosity at 40 ° C. of 20 to 800 cst (centistokes), preferably 50 to 600 cst, a fluidity of 0 to −40 ° C., preferably 0 to −30 ° C., and a flash point ( COC) is 20
An oil at 0 to 400 ° C, preferably 250 to 350 ° C, is suitably used. As the synthetic resin-based softening agent, polybutene, low molecular weight polybutadiene and the like can be used,
Mineral oil-based softeners are preferred. The softener of the component (c) improves the fluidity of the thermoplastic elastomer composition,
It improves the moldability and contributes to the improvement of the flexibility of the TPE molded body.

Optional components: In addition to the above components (a), (b) and (c), the thermoplastic elastomer composition of the present invention may contain other components according to various purposes as long as the effects of the present invention are not significantly impaired. Can be blended. Such optional components include, for example, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, anti-fog agents, anti-blocking agents, slip agents, dispersants, coloring agents, flame retardants, Antistatic agents, conductivity-imparting agents, cross-linking agents, cross-linking assistants, metal deactivators, molecular weight regulators, antibacterial agents, various additives such as fluorescent whitening agents, thermoplastic resins other than the above essential components, Elastomers and fillers other than the essential components can be exemplified, and any of these can be used alone or in combination.

The optional thermoplastic resin includes, for example, polyphenylene ether resins, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyoxymethylene homopolymer. And polyoxymethylene resins such as polyoxymethylene copolymers, and polymethyl methacrylate resins.

Examples of the optional elastomer include ethylene-propylene copolymer rubber (EPM) and ethylene-propylene-non-conjugated diene copolymer rubber (EPD).
M), ethylene-based elastomers such as ethylene-butene copolymer rubber (EBM) and ethylene-propylene-butene copolymer rubber, styrene-butadiene copolymer rubber other than the above-mentioned component (a), styrene-isoprene copolymer rubber And the like, styrene-based elastomers and polybutadiene. Further, as the filler, glass fiber,
Hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, titanium dioxide,
Carbon black and the like can be mentioned.

Composition: The mixing ratio of each component constituting the thermoplastic elastomer composition of the present invention is based on 100 parts by weight of the hydrogenated product of the block copolymer (a).
The crystalline olefin polymer of the component (b) is 3 to 350 parts by weight, preferably 4 to 300 parts by weight, and more preferably 5 to 250 parts by weight. If the amount is less than 3 parts by weight, the moldability of the thermoplastic elastomer composition is inferior. If the amount exceeds 350 parts by weight, the flexibility of the thermoplastic elastomer molded article is lost and the bleeding property of the softener is deteriorated.

The hydrocarbon rubber softener of the component (c) is used in an amount of 0 to 250 parts by weight, preferably 10 to 225 parts by weight, more preferably 4 parts by weight, per 100 parts by weight of the component (a).
0 to 200 parts by weight. When the amount of the component (c) exceeds 250 parts by weight, the rubber elasticity and heat resistance of the obtained thermoplastic elastomer molded article are inferior, and the bleeding property of the softener tends to deteriorate.

In the production of the composition for the thermoplastic elastomer of the present invention, the above components can be produced by a usual method of mechanically melt-kneading. As the melt kneader used in the mechanical melt kneading, for example, a single screw extruder, a twin screw extruder, a Brabender plastograph,
Examples thereof include a Banbury mixer, a kneader blender, and a roll, and preferably can be obtained by kneading the components in a temperature range of 145 to 300 ° C.

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. Molding: The above-mentioned thermoplastic elastomer composition can be prepared by a conventionally known method, injection molding (insert molding method, two-color molding method, sandwich molding method, gas injection molding method, etc.), extrusion molding, blown film molding, T-die film molding, It can be processed into a molded article by a molding method such as lamination molding, blow molding, hollow molding, compression molding, and calendar molding.

In particular, a product obtained by two-color injection molding of a laminate comprising a propylene-based resin and a polyester-based resin as a core material layer and a TPE molded article of the present invention as a skin material layer has flexibility (JI).
It is very effective in the field where SA hardness is 10 to 65, preferably 10 to 30) and translucency is required. Such application fields include food applications, daily necessities applications, toy / exercise equipment applications, stationery applications such as desk mats, automotive interior / exterior applications, civil engineering / architectural applications such as civil engineering sheets and waterproof sheets, AV / home appliance applications, and OA.・ Office equipment use, clothing
Examples include footwear applications, textile applications, medical device applications such as various catheters, sanitary products such as disposable diapers and sanitary products, materials for chemical and mining industries, materials for packaging and transportation, agricultural, livestock, and marine products.

[0036]

The present invention will be described more specifically with reference to the following examples. (A) Component a-1 A prototype grade "CAP518" manufactured by Shell was used. a-2 Shell Chemical Co., Ltd. product name "Clayton G1651" was used. a-3 The product name “Septon 2006” manufactured by Kuraray Co., Ltd. was used. a-4 A hydrogenated block copolymer having a styrene polymer block portion and a butadiene polymer block portion having a butadiene block portion having 80% 1,2-bonds was used. The block structure of the hydrogenated product of the styrene / conjugated diene block copolymer (a), the monomers constituting the polymer blocks (A) and (B), and the 1,2- Table 1 shows the vinyl bond amount, the weight average molecular weight, and the polymer block (A) content.

[0037]

[Table 1]

(B) Component b-1 Propylene homopolymer “Mitsubishi Polypro“ MA2P ”” (trade name) manufactured by Mitsubishi Chemical Corporation MFR: 16 g / min (230 ° C., 2.16 kg load) Flexural modulus: 14 2,000 kg / cm ² Crystallinity: 65% b-2 Mitsubishi Chemical Corporation's propylene / ethylene block copolymer “Mitsubishi Polypro“ BC-1 ”(trade name) MFR: 33 g / 10 min (230 ° C., 2.16 kg load) Flexural modulus: 10,000 kg / cm ² Crystallinity: 60% (c) component Softening material for hydrocarbon rubber: Paraffin oil “PW380” (trade name) manufactured by Idemitsu Kosan Co., Ltd. 40 ° C kinematic viscosity: 381.6 cst Flow rate: -15 ° C Flash point: 300 ° C

Example 1 and Comparative Example 1 A phenolic antioxidant (trade name “Irganox”) was added to 100 parts by weight of the total amount of the elastomer composition blended in the blending amounts (parts by weight) shown in Tables 2 and 3. 1010 ")
0.1 parts by weight were added, and the mixture was melt-kneaded at a temperature of 200 ° C. using a twin-screw extruder having a compression ratio L / D of 33 and a cylinder diameter of 45 mm, extruded into a strand from a die, and cut. Thus, pellets of the thermoplastic elastomer composition were obtained. This pellet was injected with an in-line screw type injection molding machine (a small injection molding machine manufactured by Toshiba Machine Co., Ltd .: IS90B) at an injection pressure of 500 kg / cm ² .
The sheet was molded under the conditions of an injection temperature of 220 ° C. and a mold temperature of 30 ° C. to obtain a sheet having a width of 120 mm, a length of 80 mm, and a thickness of 2 mm. This was punched out in the lateral direction for the following measurement of physical properties to obtain a sample.

(1) Flexibility The JIS-A hardness was measured according to JIS-K6301. (2) Rubber elasticity Based on JIS-K6301, compression set (23 ° C x
22 hours) [%] was measured. (3) Transparency Haze (haze value) was measured according to JIS-K7105.

(4) Presence or Absence of Bleed of Softener After the injection molded sheet was allowed to stand at 23 ° C. for 30 days, the presence or absence of stickiness on the surface was visually evaluated. (5) Molding processability Under the above molding conditions, there is no problem in releasability, and in the obtained injection molded sheet, there is no short shot,
When there was no remarkable appearance defect such as a flow mark, the molding processability was determined to be good. Tables 2 and 3 show the results of these evaluations.

[0042]

[Table 2]

[0043]

[Table 3]

Example 10 Using an in-line screw type injection molding machine (small injection molding machine manufactured by Toshiba Machine Co., Ltd .: IS90B), Mitsubishi Polypro "MG03" which is a propylene / ethylene random copolymer having an MFR of 25 g / 10 min. Trade name; flexural modulus 10,000 kg / cm ² ) at 230 ° C, 500 kg
/ Cm ² injection molding, length 120mm, width 12
A sheet (for core material) having a thickness of 0 mm and a thickness of 2 mm was formed, and this was inserted into a mold having a cavity volume of 120 mm × 120 mm × 4 mm.

Next, the gap between the molded sheet and the mold (2)
mm gap) thermoplastic elastomer of the composition of Example 2
-Injection molding machine with in-line screw type injection molding machine
Using a small injection molding machine manufactured by Shiba Machine Co., Ltd .: IS90B)
And injection pressure 500kg / cm ^TwoInjection temperature 220 ° C,
Injection molding at a mold temperature of 40 ° C, and a skin material on the core material layer
A composite injection molded article having a two-layer laminated structure in which the layers were fused was obtained.

Width 25 punched out from the laminated injection molded article
mm, a strip-shaped test piece of a composite injection molded article having a length of 100 mm was used.
The core material layer of the ethylene random copolymer was subjected to a tensile test in the direction of 180 ° C. at a tensile speed of 200 mm / min, and the peel strength at the fusion interface between the skin material layer and the core material layer was measured. The width was 25 mm.

[0047]

Industrial Applicability The thermoplastic elastomer composition of the present invention provides a translucent elastomer molded article having excellent moldability, excellent balance of rubber elasticity and weather resistance, little bleeding of a softening agent, and a high transparency.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23:02) (C08L 53/02 23:10)

Claims (3)

[Claims] (A) A- (BA) n and / or (AB) n wherein A is a monovinyl-substituted aromatic hydrocarbon polymer block; Has a 1,2-vinyl bond ratio of 55 to 90
% Of the conjugated diene polymer block, and n is an integer of 1 to 5. ] A hydrogenated product of a block copolymer represented by the formula 10:
(B) 3 parts by weight of the crystalline olefin polymer per 0 parts by weight
A thermoplastic elastomer composition, wherein the thermoplastic elastomer composition is blended in an amount of from 0 to 350 parts by weight and (c) a softening agent for hydrocarbon rubber in an amount of from 0 to 250 parts by weight. 2. The thermoplastic elastomer composition according to claim 1, wherein the crystalline olefin polymer of the component (b) is a propylene polymer. 3. The composition according to claim 1, wherein the component (a) is a styrene block part,
The thermoplastic elastomer composition according to claim 1, which is a hydrogenated product of a block copolymer having a butadiene block portion or a copolymerized block portion of butadiene and isoprene.