JP2002348434A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition excellent in moldability (such as injection moldability) and providing a molding excellent in flexibility, the sense of touch and abrasion resistance. SOLUTION: The thermoplastic elastomer composition comprises 100 pts.mass of a hydrogenated derivative (a) of a block copolymer (x) expressed by the general formula A-B-A (wherein, A denotes a polymer block of a monovinyl- substituted aromatic hydrocarbon, and B denotes an elastomeric polymer block of a conjugated diene.), 20-200 pts.mass of a polypropylene resin (b) and 50-300 pts.mass of a mineral oil-based rubber softener (c). The thermoplastic elastomer composition also comprises 1-30 pts.mass of an acryl-modified polyorganosiloxane relative to 100 pts.mass of the sum of the hydrogenated derivative (a) of the block copolymer (x), the polypropylene resin (b) and the mineral oil-based rubber softener (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition which is excellent in moldability (such as injection moldability) and whose molded article has excellent flexibility, touch and abrasion resistance. .

[0002]

2. Description of the Related Art Conventionally, vulcanized rubber or polyvinyl chloride has been mainly used as a rubber material for industrial parts such as automobile parts and home electric parts, but it is difficult to reduce the weight and recycle the vulcanized rubber. There is a problem that polyvinyl chloride has a problem that dioxin is generated during incineration and that recycling is difficult. Therefore, environmentally friendly olefin-based thermoplastic elastomers, which can be reduced in weight, are easy to recycle, and do not emit harmful gases during incineration, have been widely used as rubber materials. In recent years, among olefin-based thermoplastic elastomers, in particular, a demand for a highly flexible soft elastomer suitable as a rubber material has been increasing.

[0003]

However, in a conventional soft olefin-based thermoplastic elastomer, it is necessary to increase the compounding ratio of a rubber component to impart flexibility and to improve moldability, particularly injection moldability. In addition, it was necessary to increase the mixing ratio of the rubber softener to increase the fluidity during molding. As described above, in the conventional soft olefin-based thermoplastic elastomer, it was necessary to increase the blending ratio of the rubber component and the softening agent for rubber. However, there is a problem that the surface is not smooth, the smoothness of the surface is low, and sufficient abrasion resistance cannot be obtained.

Japanese Patent Application Laid-Open No. 58-93749 discloses that a styrene-based thermoplastic elastomer contains about 20 to 1,000,000.
A composition in which a polyorganosiloxane of 000 centistokes is dispersed to improve the smoothness and the like of the obtained molded article is disclosed, and is used for a medical tube such as a catheter. Japanese Patent Application Laid-Open No. 8-176353 discloses that a molded product obtained by adding a silicone oil of 100,000 centistokes or more to a thermoplastic elastomer containing a styrene rubber or an olefin rubber has good scratch resistance. A composition is disclosed. However, the moldability (such as injection moldability) and the flexibility, tactile sensation, abrasion resistance, etc. of the obtained molded product include performances that conflict with each other. Has not been developed yet.

Accordingly, an object of the present invention is to provide a thermoplastic elastomer composition which is excellent in moldability (injection moldability and the like) and whose molded article has excellent flexibility, touch and abrasion resistance. And

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a hydrogenated derivative (hydrogenated block copolymer) of a specific block copolymer as a rubber component (hydrogenated block copolymer) ( a) and a polypropylene resin (b);
By adding an acrylic-modified polyorganosiloxane (d) to a thermoplastic elastomer composition comprising a mineral oil-based rubber softener (c), the tactile sensation of a molded article obtained by molding the thermoplastic elastomer composition is improved. They have found that the abrasion resistance can be dramatically improved, and have arrived at the following thermoplastic elastomer composition of the present invention.

The thermoplastic elastomer composition of the present invention comprises:
A block copolymer (x) represented by the general formula ABA (where A represents a polymer block of a monovinyl-substituted aromatic hydrocarbon, and B represents an elastomeric polymer block of a conjugated diene). The block copolymer contains 20 to 200 parts by mass of a polypropylene resin (b) and 50 to 300 parts by mass of a mineral oil-based rubber softener (c) based on 100 parts by mass of the hydrogenated derivative (a). A total of 100 of the hydrogenated derivative (a) of the polymer (x), the polypropylene resin (b), and the mineral oil rubber softener (c).
It is characterized by containing 1 to 30 parts by mass of the acrylic-modified polyorganosiloxane (d) with respect to parts by mass.

The MLMFR of the hydrogenated derivative (a) of the block copolymer (x) is preferably 0.1 g / 10 minutes or less. In this specification, “M
“LMFR” means “2 based on JIS K-7210”
Melt flow rate (MFR) measured at 00 ° C. and a load of 98 N ”.

Further, in the block copolymer (x), the content of the polymer block B is 60 to 90% by mass.
It is preferable that Further, as the polymer block B of the block copolymer (x), a copolymer of isoprene and butadiene or a homopolymer of isoprene is particularly preferred. Further, in the block copolymer (x), the 1,2 microstructure in the polymer block B is preferably 25% or less. Further, in the acrylic-modified polyorganosiloxane (d),
It is preferable that the silicone content be 20 to 90% by mass.

By adopting the above-described structure, the present inventors have found that a thermoplastic resin having excellent moldability (such as injection moldability) and excellent flexibility, tactile sensation and wear resistance can be obtained. It has been found that an elastomer composition can be provided. In addition, the thermoplastic elastomer composition of the present invention can be used in a small amount per unit volume, and can achieve weight saving and resource saving,
It has been found that it is an environmentally friendly rubber material that is easy to recycle and has no danger of emitting harmful gases during incineration.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the thermoplastic elastomer composition of the present invention will be described in detail. The thermoplastic elastomer composition of the present invention is represented by the general formula ABA (where A represents a polymer block of a monovinyl-substituted aromatic hydrocarbon, and B represents an elastomeric polymer block of a conjugated diene). 20 to 200 parts by mass of a polypropylene-based resin (b) and 50 to 300 parts by mass of a mineral oil-based rubber softening agent (c) with respect to 100 parts by mass of the hydrogenated derivative (a) of the block copolymer (x) to be used. And a total of 100 parts by mass of the hydrogenated derivative (a) of the block copolymer (x), the polypropylene resin (b), and the mineral oil-based rubber softener (c). Acryl-modified polyorganosiloxane (d) in an amount of 1 to 30 parts by mass.

Hereinafter, each component constituting the thermoplastic elastomer composition of the present invention will be described in detail. [Hydrogenated derivative of block copolymer (a)] The component (a) which is a rubber component constituting the thermoplastic elastomer composition of the present invention is a block copolymer represented by the general formula ABA A hydrogenated derivative obtained by subjecting (x) to a hydrogenation treatment. In the above general formula, A represents a polymer block of a monovinyl-substituted aromatic hydrocarbon, and B represents an elastomeric polymer block of a conjugated diene.

In the block copolymer (x), examples of the monovinyl-substituted aromatic hydrocarbon as a monomer constituting the polymer block A include styrene and α-methylstyrene. Among them, styrene is particularly preferred. Examples of the conjugated diene monomer constituting the polymer block B include butadiene and isoprene, and a polymer block B composed of a copolymer of butadiene and isoprene or a homopolymer of isoprene is particularly preferable. It is.

Further, in the block copolymer (x),
The content of the polymer block B (the ratio of the polymer block B to the entire block copolymer (x)) is preferably from 60 to 90% by mass, and particularly preferably from 65 to 87% by mass. When the content of the polymer block B in the block copolymer (x) is less than 60% by mass, the elastomeric property of the hydrogenated derivative (a) of the block copolymer (x) may be reduced, and 90% by mass. %, The mechanical strength of a molded product obtained by molding the thermoplastic elastomer composition is likely to decrease, which is not preferable.

Further, in the block copolymer (x),
The 1,2 microstructure in the polymer block B is preferably 25% or less. If the 1,2 microstructure in the polymer block B exceeds 25%, the tactile sensation of a molded article obtained by molding the thermoplastic elastomer composition after a long period of time may deteriorate (a sticky feeling may be formed after a long period of time). Therefore, it is not preferable.

The hydrogenated derivative (a) obtained by subjecting the block copolymer (x) having the above composition to a hydrogenation treatment includes hydrogenated styrene-isoprenebutadiene-styrene (SEEPS), styrene- Examples include isoprene-styrene hydrogenated products (SEPS).

The hydrogenated derivative (a) of the block copolymer (x) includes at least 5 conjugated double bonds in the polymer block B constituting the block copolymer (x).
0% or more, preferably 80% or more is preferably hydrogenated, and 25% of the aromatic unsaturated bonds in the polymer block A constituting the block copolymer (x)
The following are preferably hydrogenated. An insufficient amount of hydrogenation of the block copolymer (x) is not preferable because the hydrogenated derivative (a) of the block copolymer (x) is liable to be deteriorated by heat, ultraviolet rays, or the like.

The MLMFR of the hydrogenated derivative (a) of the block copolymer (x) is preferably at most 0.1 g / 10 min, more preferably at most 0.01 g / 10 min. MLMF of hydrogenated derivative (a) of block copolymer (x)
When R exceeds 0.1 g / 10 minutes, the mechanical properties such as the breaking strength of the molded article of the obtained thermoplastic elastomer composition are remarkably reduced, and the obtained molded article has a sticky feeling, which may deteriorate the tactile sensation. Therefore, it is not preferable.

The hydrogenated derivative (a) of the block copolymer (x) having the above properties and suitable for use in the thermoplastic elastomer composition of the present invention is, for example, a trade name of Kuraray Co., Ltd. "Septon" and the like are commercially available.

[Polypropylene Resin (b)] The thermoplastic elastomer composition of the present invention is blended with a polypropylene resin (b) in order to improve the heat resistance of the obtained molded article. Examples of the polypropylene resin (b) include a propylene homopolymer, a crystalline propylene-ethylene block copolymer, a crystalline propylene-ethylene random copolymer, and a crystalline propylene-ethylene-butene random copolymer. be able to.

In the present invention, the main absorption peak temperature Tmp of the polypropylene resin (b) measured using a differential scanning calorimeter (DSC measuring apparatus) is preferably 120 ° C. or higher, and more preferably 145 ° C. or higher. Is particularly preferred. If the main absorption peak temperature Tmp is less than 120 ° C., the resulting molded article of the thermoplastic elastomer composition may have a sticky feeling, and the touch may be deteriorated, and the heat resistance of the obtained molded article may be reduced. Not preferred.

In the present specification, the main absorption peak temperature Tmp is measured by a DSC measuring device (manufactured by PerkinElmer).
After heating 3 to 5 mg of the sample to 230 ° C. and melting it, the sample was cooled to 25 ° C. at a rate of 10 ° C./min.
After holding for 5 minutes at a temperature of 10 ° C./min, the temperature is determined from an endothermic peak curve obtained when the temperature is raised to 230 ° C.

In the thermoplastic elastomer composition of the present invention, the blending amount of the polypropylene resin (b) is from 20 to 200 parts by mass based on 100 parts by mass of the hydrogenated derivative (a) of the block copolymer (x). Department. When the blending amount of the polypropylene-based resin (b) is less than 20 parts by mass, the heat resistance of the molded article of the obtained thermoplastic elastomer composition decreases, and when the blending amount exceeds 200 parts by mass, This is not preferred because the flexibility of the resulting molded article is reduced.

[Mineral oil-based rubber softener (c)] The thermoplastic elastomer composition of the present invention is used to improve the fluidity of the thermoplastic elastomer composition during molding and the flexibility of the resulting molded article. Is mixed with a mineral oil-based rubber softener (c). The mineral oil-based rubber softener (c) is composed of a combination of an aromatic ring, a naphthene ring, and a paraffin chain. Generally, the paraffin chain having 50% or more of the total carbon number is paraffin. A system in which the naphthene ring carbon number occupies 30 to 45% of the total carbon number is called a naphthene system, and an aromatic carbon number occupying 30% or more of the total carbon number is called an aromatic system.

In the thermoplastic elastomer composition of the present invention, the blending amount of the softener (c) for mineral oil rubber is based on 100 parts by mass of the hydrogenated derivative (a) of the block copolymer (x). 50 to 300 parts by mass. When the compounding amount of the mineral oil-based rubber softener (c) is less than 50 parts by mass, the fluidity of the thermoplastic elastomer composition during molding becomes insufficient, and when it exceeds 300 parts by mass, The resulting molded article of the thermoplastic elastomer composition has a sticky feeling and a deteriorated touch feeling, which is not preferable.

[Acrylic-Modified Polyorganosiloxane (d)] The thermoplastic elastomer composition of the present invention contains an acrylic resin to improve the feel and abrasion resistance of a molded article obtained by molding the thermoplastic elastomer composition. The modified polyorganosiloxane (d) is blended.

In the present specification, “acryl-modified polyorganosiloxane (d)” means “polyorganosiloxane represented by the following general formula (1)” and (meth) acrylic represented by the following general formula (2) Acrylic-modified polyorganosiloxane obtained by graft copolymerization with an acid ester "or" a polyorganosiloxane represented by the following general formula (1) and (meth) acrylic represented by the following general formula (2) More than 70 parts by weight of acid ester and this (meth)
An acrylic-modified polyorganosiloxane obtained by graft-copolymerizing a mixture of an acrylate ester and 30 parts by mass or less of another copolymerizable monomer is meant.

[0028]

Embedded image

However, in the above formula (1), X1 and X2 represent a hydrogen atom, a lower alkyl group, a general formula -SiOR
(Where R represents a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, a radical reactive group, or an organic group having an SH group).
1 to Y3 represent a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group, and Z represents a radical reactive group or SH.
Represents an organic group having a group, m represents an integer of 10,000 or less, and n represents an integer of 1 or more. In the formula (2), R1 represents a hydrogen atom or a methyl group;
Represents any one of an alkyl group, a cycloalkyl group, an alkoxy-substituted alkyl group, and an aryl group.

By blending the acrylic-modified polyorganosiloxane (d) with the thermoplastic elastomer composition, it is possible to improve the surface smoothness and abrasion resistance of the obtained molded article and to improve the tactile sensation when touched. It can be smooth. In particular, acrylic-modified polyorganosiloxane (d) obtained by graft-polymerizing a methacrylic acid ester onto a slippery polyorganosiloxane has excellent compatibility with polypropylene-based resin (b) and the like. In addition to maintaining the surface smoothness of the molded article of the obtained thermoplastic elastomer composition, the acrylic-modified polyorganosiloxane (d) remains on the molded article surface even after a long period of time.
Is preferable because it can suppress excessive bleeding.

The polyorganosiloxane and (meth) acrylate or 70% by mass or more of (meth) acrylate and 30% or less by mass of another monomer copolymerizable with this (meth) acrylate The ratio with the mixture greatly affects the surface smoothness of the obtained molded article and the compatibility between the acrylic-modified polyorganosiloxane (d) and the polypropylene resin (b), and the ratio is from 20:80 by mass ratio. 90:10 is preferred, and 30: 70-8
0:20 is more preferred.

When the content of the polyorganosiloxane (silicone content) in the acrylic-modified polyorganosiloxane (d) is less than 20% by mass, the surface smoothness of the obtained molded article may be reduced, and 90% by mass. %, The compatibility with the polypropylene resin (b) or the like is deteriorated, and the acrylic-modified polyorganosiloxane (d) may bleed to impair the appearance.

In the thermoplastic elastomer composition of the present invention, the compounding amount of the acrylic-modified polyorganosiloxane (d) depends on the hydrogenated derivative (a) of the block copolymer, the polypropylene resin (b) and the mineral oil rubber. It is 1 to 30 parts by mass with respect to 100 parts by mass in total of the softener (c). When the addition amount of the acrylic-modified polyorganosiloxane (d) is less than 1 part by mass, the molded article of the obtained thermoplastic elastomer composition has low surface smoothness, low abrasion resistance, and low tactile sensation. . In addition, when it is added in excess of 30 parts by mass, the acrylic-modified polyorganosiloxane (d) bleeds on the surface of the molded article of the obtained thermoplastic elastomer composition to impair the appearance,
The strength of the resulting molded article is significantly reduced.

As the acrylic-modified polyorganosiloxane having the above-mentioned properties and suitable for use in the thermoplastic elastomer composition of the present invention, for example, the product name “Charine” of Nissin Chemical Co., Ltd. is commercially available. I have.

The thermoplastic elastomer composition of the present invention comprises:
According to the present invention, the hydrogenated derivative of the block copolymer (a), the polypropylene resin (b), the softener for mineral oil rubber (c), and the polyorganosiloxane (d) are used. It is possible to provide a thermoplastic elastomer composition which is excellent in (e.g., injection moldability), and whose molded article has excellent flexibility, tactile sensation and abrasion resistance.

The thermoplastic elastomer composition of the present invention may contain, if necessary, an antioxidant, a heat stabilizer, an antiblocking agent, a lubricant, a weathering agent, a nucleating agent, an antistatic agent,
An anti-fogging agent, a cross-linking agent, a cross-linking aid, a coloring agent, a filler, and the like may be added. The thermoplastic elastomer composition of the present invention may contain other polyolefin-based resins or other rubber components as long as the performance is not impaired.

As the method for producing the thermoplastic elastomer composition of the present invention, known production methods used for producing general resin compositions and rubber compositions can be employed. A method of mechanically kneading (d) in a molten state can be used.

The thermoplastic elastomer composition of the present invention can be molded into a desired shape by using a commonly used thermoplastic resin molding machine, and can be formed by injection molding, extrusion molding, calendar molding, or the like. Various molding methods such as blow molding can be applied. And molded articles of the thermoplastic elastomer composition of the present invention, various parts, for example,
Automotive interior parts such as shift knobs, grab rails, armrests, hand brakes, airbag covers, handles, center console boxes, side door moldings,
It can be suitably used as automotive exterior parts such as mudguards, industrial parts such as grips for various industrial machines, office supplies such as writing implement grips, and household electric parts such as grips for various home appliances.

[0039]

EXAMPLES Examples and comparative examples according to the present invention will be described below. In Examples 1 to 7 and Comparative Examples 1 to 7,
A hydrogenated derivative of a block copolymer, a polypropylene-based resin, a mineral oil-based rubber softener, and an acrylic-modified polyorganosiloxane are blended, and the obtained composition is subjected to a coaxial twin-screw extruder KTX-37 (Kobe Steel ( And the mixture was melt-kneaded to prepare a pelletized thermoplastic elastomer composition. Tables 1 and 2 show the evaluation results of the composition of each of the examples and the comparative examples, and the evaluation of each of the obtained thermoplastic elastomer compositions. In Comparative Example 1,
A thermoplastic elastomer composition was obtained without adding the acrylic-modified polyorganosiloxane.

[0040]

[Table 1]

[0041]

[Table 2]

Hereinafter, the raw materials used in each of the examples and comparative examples, and evaluation items and evaluation methods of the obtained thermoplastic elastomer composition will be described.

(Raw Materials) Raw materials used in each of Examples and Comparative Examples will be described. 1. Hydrogenated derivative of block copolymer (a) As component (a), SEP-1 to SEP-3 shown in Table 3
Was used. As described above, since the component (a) is a hydrogenated derivative of the block copolymer (x) composed of the polymer block A and the polymer block B, Table 3 shows the block copolymer (x). The composition of the polymer blocks A and B is described. Further, since the polymer block A is a homopolymer of styrene, the styrene content in the component (a) is also described. Further, the ratio of the 1,2 microstructure in the polymer block B of the component (a) (block copolymer (x)) and the component (a)
MLMFR is also described. As shown in Table 3, SEP-1 and SEP-2 did not flow at the time of MLMFR measurement, and MLMFR was less than 0.01 g / 10 minutes. On the other hand, the MLMFR of SEP-3 is 5g.
/ 10 minutes, and the fluidity in the molten state was high.

[0044]

[Table 3]

2. Polypropylene resin (b) PP-1 shown below was used as the component (b). PP-1: polypropylene (ethylene content: 0.5% by mass or less, M measured based on JIS K-7210
FR: 60 g / 10 min, main absorption peak temperature Tmp measured using a DSC measurement device: 163 ° C.)

3. Mineral oil-based rubber softener (c) The following PW-380 was used as the component (c). PW-380: paraffinic oil (pour point: -15
Kinematic viscosity at 98 ° C and 98 ° C: 38.1 centistokes, flash point: 300 ° C, Idemitsu Kosan “PW-380”)

4. Acrylic-modified polyorganosiloxane (d) The following SA-1 and SA-2 were used as component (d). SA-1: Acrylic-modified polyorganosiloxane with a silicone content of 70% SA-2: Acrylic-modified polyorganosiloxane with a silicone content of 10% In Tables 1 and 2, the amount of the acrylic-modified polyorganosiloxane added Is the total amount of the components (a), (b), and (c) in (), and the amount added is 100 parts by mass.

(Evaluation Items and Evaluation Methods) Evaluation items and evaluation methods of the obtained thermoplastic elastomer composition will be described in each of Examples and Comparative Examples.

(A) Evaluation of thermoplastic elastomer composition A-1. MFR In each Example and Comparative Example, the MFR of the obtained thermoplastic elastomer composition was measured based on JIS K-7210. A-2. Shore A Hardness The Shore A hardness of the thermoplastic elastomer compositions obtained in Examples 1 to 7 and Comparative Examples 1 and 3 to 7 was determined according to ASTM D.
2240. A-3. Shore D hardness The Shore D hardness of the thermoplastic elastomer composition obtained in Comparative Example 2 was measured based on ASTM D2240.

(B) Evaluation of Molded Article The thermoplastic elastomer compositions obtained in each of the examples and comparative examples were injection-molded to obtain a 100 × 200 mm.
A flat molded product having a thickness of 2 mm was prepared, and the obtained molded product was evaluated as follows.

B-1. Wear resistance For the molded products obtained in each of the examples and comparative examples,
A wear resistance test was performed as follows. Set the cotton (Kanakin No. 3) for the Japanese Standards Association JIS dyeing fastness test on a wear jig in a tester Sangyo Gakudo type friction fastness tester (AB-301), and wear the surface of the obtained molded product on a wear jig. The tool is placed and a vertical load of 200 g is applied.
m was reciprocated 200 times at a speed of 30 reciprocations per minute. The test was performed once in each of the examples and comparative examples. After the test, observe the test points visually,
The evaluation was performed based on the following criteria. <Judgment Criteria> 跡: No trace of wear and no discoloration on the test cotton were observed at all. Δ: Either or both of traces of wear and discoloration on the test cotton were slightly observed. ×: Traces of wear were observed on the molded product, and discoloration on the test cotton was clearly observed.

B-2. Appearance The appearance of the molded articles obtained in each of Examples and Comparative Examples was visually observed and evaluated based on the following criteria. <Judgment Criteria> フ ロ ー: There is no flow mark, gloss unevenness, etc. Δ: Flow marks, gloss unevenness, etc. are slightly observed, but they are to the extent that there is no problem as a product. X: Flow marks, gloss unevenness, etc. are remarkably observed, and there is a problem as a product.

B-3. Tactile sensation The surface of the molded product obtained in each of the examples and comparative examples was directly touched with bare hands, and the tactile sensation was evaluated based on the following criteria. The same molded product was evaluated twice immediately after molding and three months later. Hereinafter, "Tactile sensation immediately after molding",
The “tactile sensation after 3 months” is referred to as “initial tactile sensation” and “tactile sensation after long-term lapse”, respectively. <Judgment Criteria> ：: No sticky feeling, showing a smooth and good feeling. Δ: Slightly sticky feeling is not felt. X: The stickiness is considerably felt.

B-4. Flexibility The flexibility of the molded articles obtained in each of the examples and comparative examples was evaluated based on the feeling when touched or gripped with bare hands according to the following criteria. <Judgment Criteria> ：: Moderate flexibility, suitable for applications requiring a soft material. ×: Insufficient flexibility, not suitable for applications requiring a soft material.

(Results) As shown in Table 1, in Examples 1 to 7 in which the thermoplastic elastomer composition of the present invention was prepared, the MFR of each of the obtained thermoplastic elastomer compositions was 20 g / 10 min or more. In addition, while exhibiting good fluidity in a molten state, the Shore A hardness was as low as 90 or less, and had flexibility. The good fluidity in the molten state means that the composition has excellent injection moldability. In addition, the molded article of the obtained thermoplastic elastomer composition has excellent abrasion resistance, initial tactile sensation, tactile sensation after a long period of time, and flexibility, and has a paraffinic oil (a softening agent for mineral oil rubbers) even after a long period of time. )
No bleeding occurred, and an appearance having high smoothness could be maintained.

On the other hand, as shown in Table 2, the thermoplastic elastomer compositions obtained in Comparative Examples 1 to 7 exhibited the same MFR and Shore A hardness or Shore D hardness as in Examples 1 to 7, The fluidity and flexibility in the molten state were comparable. However, the molded article obtained in Comparative Example 1 in which the component (d) was not blended had good appearance without gloss unevenness and flow mark, but low abrasion resistance.
Both the initial tactile sensation and the tactile sensation after a long time passed were poor. Further, the molded article obtained in Comparative Example 2 in which the blending amount of the component (b) was set to be more than 200 parts by mass with respect to 100 parts by mass of the component (a) was excellent in abrasion resistance, appearance, initial tactile sensation, long term Although the touch after the passage was good, the flexibility was insufficient.

The amount of the component (c) was changed to the component (a) 1
The molded product obtained in Comparative Example 3 in which the amount was set to be more than 300 parts by mass with respect to 00 parts by mass was excellent in abrasion resistance, and had good appearance without gloss unevenness and flow marks,
Both the initial tactile sensation and the tactile sensation after a long time passed were poor. Further, the compounding amount of the component (d) is changed to the components (a), (b),
The molded product obtained in Comparative Example 4 in which the amount was set to be more than 30 parts by mass with respect to the total of 100 parts by mass was excellent in abrasion resistance, but both the initial tactile sensation and the tactile sensation after a long time passed were poor, and the flow mark And gloss unevenness was remarkably observed.

In Comparative Example 5 in which a 10% acryl-modified polyorganosiloxane having a silicone content of less than 20% was used as the component (d), the appearance was good without gloss and flow marks, but the anti-glare property was good. Low abrasion,
Both the initial tactile sensation and the tactile sensation after a long time passed were poor. Component (a) having a MLMFR higher than 0.1 g / 10 min.
Although the molded articles obtained in Comparative Examples 6 and 7 using Comparative Example 1 had slightly superior abrasion resistance, both the initial tactile sensation and the tactile sensation after a long period of time were poor, and flow marks and gloss unevenness were remarkably observed. Was.

From the above results, according to the present invention, a thermoplastic elastomer composition having excellent moldability (such as injection moldability) and excellent flexibility, tactile sensation and abrasion resistance can be obtained. It turns out that it can be provided.

[0060]

The thermoplastic elastomer composition of the present invention is a material having excellent moldability (such as injection moldability) and a molded article having excellent flexibility, tactile sensation and abrasion resistance. Further, since the thermoplastic elastomer composition of the present invention may be used in a small amount per unit volume,
It is an environmentally friendly material that can reduce weight and save resources, is easy to recycle, has no risk of emitting harmful gases during incineration.

Continuation of the front page (72) Inventor Kenji Fujitani 2-3-2 Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term in the Research and Development Center, Technology Headquarters, Japan Polyolefin Co., Ltd. 4J002 AE05Y BB11X BB12X BB14X BB15X BN174 BP01W BP02X CP034 GM00 GN00

Claims (7)

[Claims] 1. A block copolymer represented by a general formula ABA (where A represents a polymer block of a monovinyl-substituted aromatic hydrocarbon, and B represents an elastomeric polymer block of a conjugated diene). Hydrogenated derivative (a) of coalescence (x)
100 parts by mass of the polypropylene resin (b) 2
0 to 200 parts by mass, and a mineral oil-based rubber softener (c) 50
And 300 parts by mass, and a total of 100 parts by mass of the hydrogenated derivative (a) of the block copolymer (x), the polypropylene-based resin (b), and the mineral oil-based rubber softener (c). A thermoplastic elastomer composition comprising 1 to 30 parts by mass of an acrylic-modified polyorganosiloxane (d) based on the total amount of the thermoplastic elastomer composition. 2. The thermoplastic elastomer composition according to claim 1, wherein the MLMFR of the hydrogenated derivative (a) of the block copolymer (x) is 0.1 g / 10 minutes or less. 3. In the block copolymer (x),
3. The thermoplastic elastomer composition according to claim 1, wherein the content of the polymer block B is from 60 to 90% by mass. 4. 4. In the block copolymer (x),
The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the polymer block B comprises a copolymer of isoprene and butadiene. 5. In the block copolymer (x),
The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the polymer block B comprises a homopolymer of isoprene. 6. In the block copolymer (x),
The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the 1,2 microstructure in the polymer block B is 25% or less. 7. The thermoplastic resin according to claim 1, wherein the acrylic-modified polyorganosiloxane (d) has a silicone content of 20 to 90% by mass. Elastomer composition.