JP2002187981A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic elastomer composition improved in extrudability without deteriorating rubber elasticity and mechanical strengths. SOLUTION: This composition comprises 20-90 wt.% (A) olefin rubber and 10-80 wt.% (B) following polypropylene composition. Component B is a polypropylene composition comprising (b1) a polypropylene homopolymer or propylene copolymer containing below 1 wt.% olefins other than propylene, each of which has an MFR of 10-1,000 g/10 min and (b2) a propylene copolymer having a weight-average molecular weight of 500,000-10,000,000 and containing 1-15 wt.% olefins other than propylene, wherein the amount of component (b1) is 50-90 wt.% based on the total weight of components (b1) and (b2), and the amount of component (b2) is 10-50 wt.% based thereon (provided that the total of the both is 100 wt.%) and having specified physical properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic elastomer composition, and more particularly, to an olefin-based thermoplastic elastomer composition having improved moldability without impairing rubber elasticity.

[0002]

2. Description of the Related Art In recent years, thermoplastic elastomers, which are rubber-like soft materials and do not require a vulcanization step and have the same moldability as thermoplastic resins, have been used for automobile parts, home electric parts, medical equipment, foodstuffs It is attracting attention and used in the fields of equipment parts, electric wires and miscellaneous goods. By the way, the olefin elastomer, which is one of the above thermoplastic elastomers,
Despite excellent rubber elasticity, it is not possible to obtain an extruded product with a smooth molded product surface, poor shapeability, and cut edges (a thin section of the extruded product is not smooth but jagged). There's a problem. In order to obtain an excellent extruded product, various improvements have been attempted in, for example, JP-A-5-170930, but the conventional proposal has a problem that rubber elasticity is sacrificed.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a thermoplastic elastomer having improved extrudability without deteriorating rubber elasticity and mechanical strength. It is to provide a composition.

[0004]

As a result of various studies, the present inventors have achieved the above object by using an olefin rubber and a specific polypropylene composition obtained by at least two-stage polymerization. We have found that this can be easily achieved, and have completed the present invention.

That is, the gist of the present invention is a thermoplastic elastomer composition comprising 20 to 90% by weight of an olefin rubber (A) and 10 to 80% by weight of a polypropylene composition (B). ) Is a thermoplastic elastomer composition characterized by comprising the following composition:

<Polypropylene composition (B)> MFR =
10 to 1000 g / 10 min of homopolypropylene or copolymer (b1) having an olefin content other than propylene of less than 1% by weight and a weight average molecular weight of 500,000 to 10,000,000 and an olefin content of other than propylene of 1 to 15% by weight. It consists of a propylene copolymer (b2) and comprises a component (b)
The proportion of the component (b1) is 50 to 90% by weight and the proportion of the component (b2) is 10 to 5 based on the total of 1) and the component (b2).
0% by weight (the total amount of both is 100% by weight),
A polypropylene composition having the following physical properties (the above MFR
Is a measured value under the conditions of a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K7210, Table 1, Condition 14.
The same applies to (1) and (2) below).

[0007]

(1) MFR = 0.1 to 20 g / 10 min (2) Melt tension (MT) and MFR satisfy the following relationship: logMT> −0.97 × logMFR + 1.23 (3) Longest relaxation time (τd) ) Is 100 seconds or more

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present specification, unless otherwise specified, the value of MFR is in accordance with Table 1 of JIS K7210, condition 14, and
It means a measured value under the conditions of a temperature of 230 ° C. and a load of 21.18 N.

The olefin rubber used as the component (A) in the present invention is an ethylene-propylene copolymer rubber,
Ethylene-propylene-conjugated diene copolymer rubber (EP
DM), ethylene-1-butene-non-conjugated diene copolymer rubber, and propylene-1-butene-non-conjugated diene copolymer rubber. Of these, EPDM is preferred.

Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, with ethylidene norbornene being particularly preferred. More preferable specific examples of the component (A) include an ethylene content of 55 to 75% by weight and a non-conjugated diene content of 1 to
10% by weight of EPDM. If the ethylene content is less than 55% by weight, extrudability tends to decrease, and if it exceeds 75% by weight, flexibility tends to be lost.

The polypropylene composition used as the component (B) in the present invention is a novel composition containing the component (b1) and the component (b2) at a specific ratio, and particularly has a high melt tension and a processing property. And is obtained by the following two-stage polymerization reaction.

As the catalyst system for the polymerization reaction, a catalyst system mainly comprising a titanium-containing solid catalyst component and an organoaluminum compound, or a metallocene transition metal compound having at least one π-electron conjugated ligand is used. .

The titanium-containing solid catalyst component is a known supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide and an electron donating compound, or a known catalyst component containing titanium trichloride as a main component. To be elected. The aluminum compound of the promoter is represented by the general formula AlR _n X
_3-n (wherein R is a hydrogen atom which may be different from each other, a methyl group or an ethyl group, X is a halogen atom, and n is 3 ≧ n
> 1.5). When the titanium-containing solid catalyst component is a carrier-supporting catalyst component containing a solid magnesium compound, AlR ₃ or AlR ₃ and AlR ₂
It is preferable to use a mixture of X. On the other hand, in the case of titanium trichloride or a catalyst component containing titanium trichloride as a main component, it is preferable to use AlR ₂ X. Further, in addition to the above catalyst and cocatalyst components, known electron donating compounds can be used as the third component.

The metallocene compound may be used as a co-catalyst with aluminoxanes, or may be used by being supported on silica or a clay mineral. Specific examples of such a metallocene catalyst are described in JP-A-8-217929,
JP-A-8-238731, JP-A-8-18381
4, JP-A-8-208733, JP-A-8-208733
85707 and the like.

The polymerization reaction is carried out in the presence of, for example, an inert solvent such as hexane or heptane, but it can also be carried out in the absence, that is, in the presence of liquid propylene or in gaseous propylene. In addition, the polymerization reaction may be performed in either a batch system using one polymerization tank, a continuous system using two or more polymerization tanks connected in series, or a continuous system using a tubular polymerization reactor. And, as the other olefin copolymerized with propylene, ethylene, 1-butene, 1-hexene, 1-octene and the like can be used.

The polymerization reaction is carried out in two steps (two steps), but may additionally be carried out in three or four steps. The catalyst is generally added before the polymerization in the first stage. Although replenishment of the catalyst in the latter stage is not necessarily excluded, it is preferable to add the catalyst in the first stage in order to obtain characteristics that cannot be obtained by resin blending.

In the first step, propylene or propylene and another olefin are polymerized in the presence of hydrogen, and MFR =
A copolymer (b1) having an olefin content of less than 1% by weight other than homopolypropylene or propylene of 10 to 1000 g / 10 min is obtained.

In the first step, hydrogen is used for controlling the MFR of the obtained polymer to be in the range of 10 to 1,000. The hydrogen concentration (in the case of slurry polymerization, refers to the concentration in the gas phase part, in polymerization in liquid propylene or in the gas phase method, refers to the content in the monomer) is usually 1 to 50 mol.
1%, preferably 3 to 30 mol%. Other olefins copolymerized with propylene can be supplied intermittently or continuously with propylene or the like. The polymerization temperature in the first step is usually 40 to 90 ° C, and the polymerization ratio in this step is 50 to 90% by weight (preferably 60 to 80% by weight) based on the total amount of polymerization.

The second step is a polymerization for obtaining a high molecular weight component. The polymerization is carried out in a substantially hydrogen-free state having a hydrogen concentration of 0.1 mol% or less, and the weight average molecular weight is 500,000 to 10,000,000 (preferably and preferably Is 800,000 to 5,000,000) and the content of olefins other than propylene is 1 to 15% by weight to obtain a propylene copolymer (b2).

The copolymer comonomer is selected from ethylene, 1-butene, 1-hexene, 1-octene and the like, and its preferred content is 3 to 10% by weight. If the comonomer content is too high or too low, the dispersion of the high molecular weight component becomes poor, and the effect of improving the melt tension is reduced. The polymerization temperature in the second step is usually 40 to 90 ° C, preferably 50 to 80 ° C, and the polymerization ratio in this step is 10 to 50% by weight based on the total polymerization amount.
(Preferably 20 to 40% by weight).

Component (b2) has a weight average molecular weight of GPC
Is used to measure the weight average molecular weights of both the component (b1) and the final polymer (component (b1) and component (b2)). Can be calculated.

MFR of final polymer (ie, polypropylene composition (B)) obtained in the first and second steps
Is 0.1 to 20 g / 10 min (preferably 0.5 to
10 g / 10 min), and the other olefin content is usually 0.5 to 8.5% by weight, preferably 1.0 to 8.5% by weight.
5.0% by weight.

The polypropylene composition (B) must satisfy the following relationship between the melt tension (MT) and the MFR.

[0024]

## EQU1 ## logMT> −0.97 × logMFR + 1.23

The above relational expression expresses the balance between the melt tension and the fluidity, and satisfying the above expression means that the fluidity and the extrusion characteristics are good while expressing a high melt tension. I do. That is, the novel polypropylene composition (B) used in the present invention means that the balance between processing characteristics such as blow molding, foam molding, and thermoforming and extrusion characteristics is good. On the other hand, the general-purpose polypropylene-based resin composition satisfies the relationship of left-hand side <right-hand side in the above formula, and the MFR at the same MT is smaller than that of the polypropylene composition (B) used in the present invention. I do.

The polypropylene composition (B) has a feature that the longest relaxation time (τd) is 100 seconds or more. The above-mentioned τd is obtained by stress relaxation measurement, and means a time required for the deformed molecular chain to return to a random state before deformation through orientation relaxation in which the deformed molecular chain relaxes without changing its orientation. This τd is closely related to processing characteristics such as blow molding, foam molding and thermoforming, and it is considered that the larger τd is, the more excellent the processing characteristics are.

Further, τd tends to be longer due to the presence of the high molecular weight component and / or the branched component, but does not always coincide with the nonlinearity of the elongational viscosity. That is, τ
d does not specify the non-linearity of the elongational viscosity, but specifies the uniform extensibility during elongational deformation. τd is 1
If the time is shorter than 00 seconds, the contribution of the long relaxation time component becomes small, which impairs the processing characteristics. That is, τd ≧ 1
Satisfaction of 00 seconds is an indispensable condition in molding processing requiring high melt tension.

The thermoplastic elastomer composition of the present invention comprises:
It contains the olefin rubber (A) and the polypropylene composition (B) as essential components. The use ratio of each component is as follows: component (A) 20 to 90% by weight, component (B) 10 to 8
0% by weight, and in particular, component (A) 30 to 8
The content is preferably 5% by weight and the component (B) 15 to 70% by weight. When the use ratio of the component (A) is less than 20% by weight (when the use ratio of the component (B) exceeds 80% by weight)
In the case of the composition, the flexibility of the composition and the obtained molded article is lost, and when the use ratio of the component (A) exceeds 90% by weight (when the use ratio of the component (B) is less than 10% by weight), the moldability is deteriorated. Worsens.

In the present invention, the thermoplastic elastomer composition is preferably a composition obtained by a dynamic heat treatment in the presence of an organic peroxide. Here, "dynamically heat-treating" refers to kneading in a molten state or a semi-molten state.

As the above-mentioned organic peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) Hexyne-3,1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy) -3,5-trimethylcyclohexane,
2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne-3, dicumyl peroxide and the like. Among them, particularly, in terms of odor and scorch, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane or 2,5-dimethyl-2,5
-Di (t-butylperoxy) hexyne-3 is preferred.

The amount of the organic peroxide to be added is usually 0.005 to 100 parts by weight of the mixture of the components (A) and (B).
3 parts by weight, preferably selected from the range of 0.05 to 2 parts by weight. If the amount of the organic peroxide is less than 0.005 parts by weight, the effect of the crosslinking reaction is small, and if it is more than 3 parts by weight, the appearance of the extruded material is deteriorated and is not economically advantageous.

In the present invention, a crosslinking assistant can be used together with the organic peroxide. The main crosslinking aids are
Sulfur, p-quinonedioxime, nitrosobenzene, diphenylguanidine, N-methyl-N-4-dinitrosoaniline, trioxylpropane-N, N-m-phenylenedimaleimide, a peroxy crosslinking auxiliary, divinyl Multifunctional methacrylate monomers such as benzene, triallyl isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, polyfunctional such as vinyl butyrate and vinyl stearate There are vinyl monomers and the like. By using the compound as described above, a uniform and mild crosslinking reaction can be expected.

The amount of the crosslinking aid to be added is usually 0.005 to 100 parts by weight of the mixture of the components (A) and (B).
4 parts by weight, preferably selected from the range of 0.05 to 3 parts by weight. If the amount of the crosslinking aid is less than 0.005 parts by weight, no effect is exhibited, and if it is more than 4 parts by weight, it is not economically advantageous.

The dynamic heat treatment of the mixture of the components (A) and (B) is performed, for example, using a kneading device such as a Banbury mixer, a mixing roll, a kneader, an extruder. The temperature is preferably such that the half-life of the organic peroxide used is less than 1 minute, and is usually selected from 130 to 280 ° C. The time is usually selected from a range of 1 to 30 minutes.

In the present invention, a mineral oil-based softener can be used in order to further improve the mechanical properties and workability. Examples of such a mineral oil-based softener include paraffin-based, naphthene-based, and aromatic-based softeners, and paraffin-based softeners are particularly preferable.

In the thermoplastic elastomer composition of the present invention, in addition to the above-mentioned components, other optional components can be blended according to various purposes within a range that does not significantly impair the effects of the present invention. Such components include, for example, fillers, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers,
Neutralizing agent, lubricant, anti-fogging agent, anti-blocking agent, slip agent, dispersant, coloring agent, flame retardant, antistatic agent, conductivity-imparting agent, metal deactivator, molecular weight regulator, antibacterial agent, Examples of the additives include various additives such as molds, fluorescent whitening agents, etc., thermoplastic resins and elastomers other than the essential components, fillers, and the like.

Examples of the thermoplastic resin other than the essential components include ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene / acrylic ester copolymer, ethylene・ Ethylene such as methacrylic acid ester copolymer α-
Olefin copolymer, polyethylene, polyolefin resin such as polybutene-1 resin, polyphenylene ether resin, polyamide resin such as nylon 6, nylon 66, polyethylene terephthalate, polyester resin such as polybutylene terephthalate, polyoxymethylene homopolymer, Examples thereof include polyoxymethylene resins such as polyoxymethylene copolymers, and polymethyl methacrylate resins.

The elastomer other than the essential components includes, for example, styrene / butadiene copolymer rubber,
Styrene-based elastomers such as styrene-isoprene copolymer rubber are exemplified. Further, examples of the filler include glass fiber, hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, titanium dioxide, and carbon black.

In the present invention, other components such as a mineral oil softener can be mixed at any stage. For example, the mineral oil-based softener may be oil-extended on the olefin rubber of the component (A) in advance. The amount of the mineral oil-based softener to be used is generally selected from the range of 150 parts by weight or less, preferably 130 parts by weight or less, per 100 parts by weight of the mixture of the components (A) and (B). If a mineral oil-based softener is used, its minimum amount is usually 0.1 part by weight per 100 parts by weight of the mixture of components (A) and (B).

The thermoplastic elastomer composition obtained by the method of the present invention can be easily molded by an apparatus used for ordinary thermoplastic resins, and can be, for example, extruded or injection molded. The composition according to the present invention is particularly suitable for profile extrusion molding, foam molding, blow molding and the like in which a complicated cross-sectional shape or a cross-sectional shape changes during molding. Suitable for roof molding, window molding, flush mount molding, weather strip, glass run channel, instrument panel, automotive parts such as rack & pinion boots, gaskets for electric refrigerators and vending machines, packing around windows, etc. I have.

[0041]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition, the materials used as each component in the following examples are as follows. In the following, "%" means% by weight.

(A1): ethylene-propylene-ethylidene norbornene copolymer rubber (ethylene content 70%,
(Ethylidene norbornene content 5.5%), oil extension 100
%, ML = 400, (ML: Mooney viscosity (ML1 + 4
100 ° C), according to ASTM D-927-57T,
same as below)

(A2): Ethylene-propylene-ethylidene norbornene copolymer rubber (ethylene content 66%,
(Ethylidene norbornene content 4.5%), ML = 89

(B1): Propylene copolymer (MFR)
= 3.9 g / 10 min), flexural modulus: 1000 MPa
(N-heptane, Mg-supported titanium catalyst (solid catalyst prepared in the same manner as in Example 1 of JP-A-4-348113) and triethylaluminum were added to a stainless steel autoclave, and the temperature was raised to 70 ° C to supply hydrogen and propylene. Then, a propylene homopolymer having an MFR of 100 g / 10 min was produced at 70% by weight of the whole polymer, and then hydrogen was purged to supply ethylene and propylene to give an ethylene content of 10%.
An ethylene / propylene copolymer having a weight-average molecular weight of 4,000,000, which is 30% of the total polymer. )

(B2): Propylene copolymer (MFR)
= 0.7 g / 10 min), flexural modulus: 850 MPa

(B3): Propylene copolymer (MFR)
= 1.9 g / 10 min), flexural modulus: 1850 MPa

(C): ethylene-octene copolymer (M
FR (190 ° C. 21.18 N) = 0.5 g / 10 min),
Specific gravity: 0.867

(D): paraffinic process oil

POX: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane

TMP: trimethylolpropane trimethacrylate

The evaluation methods used are as follows (1)-
It is as (4). For the measurements (1) and (2), a 2 mm-thick sheet obtained by injection molding at a cylinder temperature of 220 ° C. and a mold temperature of 40 ° C. was used.

(1) Hardness: in accordance with JIS K6253 (JIS-A, instantaneous value)

(2) Compression set: JIS K6262
Compliant with (70 ° C, 22 hours, 25% compression)

(3) Surface roughness Ra: JIS B0601
, And molding of the sample and measurement of Ra were performed as follows. That is, using a φ40 mm single screw extruder manufactured by Mitsubishi Heavy Industries (full flight screw with a compression ratio of 2.2, a flat die having a width of 25 × 1 mm in thickness), a molding temperature below the hopper: 160 ° C., a cylinder: 170 to 190 ° C., a die :
The molding was performed under the conditions of 180 ° C. and a screw rotation speed of 25 rpm. And about the obtained extruded product surface,
The center line average roughness Ra was measured with a surface roughness meter “Surfcom 570A” manufactured by Toyo Seimitsu Co., Ltd.

(4) Edge Smoothness: The condition of the edge of the flat extruded product was determined according to the criteria shown in Table 3 below.

[0056]

[Table 3] <Criterion of Edge Smoothness> ○: Smooth △: Rough on touch ×: Cut off of edge can be confirmed visually

(5) MT: using a Capillograph manufactured by Toyo Seiki Seisakusho, cylinder temperature 190 ° C., orifice L /
D = 8.1 / 2.095 (mm), piston speed 1
The measurement was performed under the conditions of 0 mm / min and a take-up speed of 3.9 m / min.

(6) τd: “RM manufactured by Rheometrics”
S-800 ”, parallel plate diameter 25m
m, a gap of 1.5 mm, a temperature of 200 ° C. and 240 ° C., a strain of 50 and 100%, and measure a relaxation elastic modulus G (t) to create a master curve. Using the obtained G (t), “JOURNAL OF POLYMER SCIENCE, VOL.
443-456 (1959).

M for the components (B1) to (B3)
Table 5 shows the measurement results of FR, MT and τd. In Table 5, the composition ○ that satisfies the formula described in Table 4 below, and the composition that did not 式 were X.

[0060]

Table 4 MT: logMT> 0.97 × logMFR + 1.23 τd: τd> 100

[0061]

[Table 5]

Example 1 Mixture 10 of 80% of component (A1) and 20% of component (B1)
0.35 parts by weight of POX and 0.8 of TMP per 0 parts by weight
Parts by weight and blended for 1 minute with a Henschel mixer, then a co-axial twin screw extruder (“KTX4 made by Kobe Steel”).
4), L / D = 41, number of cylinder blocks = 11), into the first supply port at a rate of 40 kg / h, and further, supply oil at 10 parts by weight from the second supply port to perform melt kneading. Pelletized. Table 6 shows the evaluation results.

The first supply port is provided in the first cylinder block (C1), and the second supply port described below is
It is provided at the first cylinder block number (C7),
The components supplied to the first supply port are sufficiently mixed before reaching the second supply port, and the components supplied to the second supply port are sufficiently mixed before reaching the discharge port ( same as below).

Example 2 Mixture 10 of 75% of Component (A2) and 25% of Component (B1)
0.21 parts by weight of POX and 0.5 parts by weight of TMP per 0 parts by weight
3 parts by weight, and blended for 1 minute with a Henschel mixer. Then, a co-axial twin screw extruder ("KTX" manufactured by Kobe Steel, Ltd.)
44 ", L / D = 41, the number of cylinder blocks = 11) into the first supply port at a rate of 40 kg / h, and
The oil was introduced from the supply port so as to be 25 parts by weight, and the mixture was melt-kneaded to form pellets. Table 6 shows the evaluation results.

Example 3 In Example 2, the amount of POX was 0.35 parts by weight, and TM
The same operation as in Example 2 was performed except that the amount of P was changed to 0.8 parts by weight. Table 6 shows the evaluation results.

Comparative Example 1 The same operation as in Example 1 was performed, except that the component (B1) was changed to the component (B2). Table 6 shows the evaluation results.

Comparative Example 2 The same operation as in Example 2 was performed, except that the component (B1) was changed to the component (B2). Table 6 shows the evaluation results.

Comparative Example 3 The same operation as in Example 2 was performed, except that the component (B1) was changed to the component (B3). Table 6 shows the evaluation results.

Comparative Example 4 Mixture 10 of 75% of Component (A1) and 25% of Component (B1)
0.35 parts by weight of POX and 0.8 of TMP per 0 parts by weight
Parts by weight and blended for 1 minute with a Henschel mixer, then a co-axial twin screw extruder (“KTX4 made by Kobe Steel”).
4 ", L / D = 41, number of cylinder blocks = 11), into the first supply port at a rate of 40 kg / h, and further, component (C) from the second supply port to 25 parts by weight. The mixture was melt-kneaded to form pellets. Table 6 shows the evaluation results.

Comparative Example 5 The same operation as in Example 3 was performed, except that the component (B1) was changed to the component (B2). Table 6 shows the evaluation results.

[0071]

[Table 6]

<Evaluation of Results> The following is clear from the comparison between Examples and Comparative Examples.

(1) Comparative Example 1 is a case where the component (B1) is changed to the component (B2) in Example 1, and is inferior to Example 1 in surface roughness and edge smoothness.

(2) Comparative Example 2 is the same, and is inferior in surface roughness and edge smoothness as compared with Example 2.

(3) Comparative Example 3 is a case where the component (B1) is changed to the component (B3) in Example 2, and is inferior in surface roughness and edge smoothness as compared with Example 1.

(4) Comparative Example 4 is a case where the component (B1) was changed to the component (B2) in Example 2 and the component (C) was further added. Inferior.

(5) Comparative Example 5 is a case where the component (B1) is changed to the component (B2) in Example 3, and is inferior in surface roughness and edge smoothness as compared with Example 1.

[0078]

According to the present invention described above, a thermoplastic elastomer composition having improved extrudability without particularly deteriorating rubber elasticity and mechanical strength is provided. large.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Ken Ishikawa 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. Yokkaichi Office (72) Inventor Fusaaki Kato 1 Tohocho, Yokkaichi-shi, Mie Japan Nippon Polychem Co., Ltd. (72) Inventor Yoshiharu Yamamoto 1 Toho-cho, Yokkaichi, Mie Prefecture Japan Polychem Corporation Process Development Center (72) Inventor Hideo Sakurai 1 Toho-cho, Yokkaichi-shi, Mie Process Japan Polychem Co., Ltd. F-term in development center (reference) 4F070 AA12 AA15 AB11 AB16 GA05 4J002 BB00W BB12X BB14W BB14Y BB15W GN00 GQ00

Claims (2)

[Claims] 1. A thermoplastic elastomer composition comprising 20 to 90% by weight of an olefin-based rubber (A) and 10 to 80% by weight of a polypropylene composition (B), wherein the polypropylene composition (B) has the following composition: A thermoplastic elastomer composition comprising: <Polypropylene composition (B)> MFR = 10 to 100
0 g / 10 min of a homopolypropylene or a copolymer having an olefin content other than propylene of less than 1% by weight (b
1) and a propylene copolymer (b2) having a weight-average molecular weight of 500,000 to 10,000,000 and an olefin content other than propylene of 1 to 15% by weight, based on the total of the component (b1) and the component (b2) The ratio of the component (b1) is 50 to 9;
0% by weight, the proportion of the component (b2) is 10 to 50% by weight (the total amount of both is 100% by weight), and a polypropylene composition having the following physical properties (the above MFR is JIS
It is a measured value under the conditions of a temperature of 230 ° C. and a load of 21.18 N according to Table 1 and Condition 14 of K7210, and the following (1)
And (2)). (1) MFR = 0.1 to 20 g / 10 min (2) Melt tension (MT) and MFR satisfy the following relationship: logMT> −0.97 × logMFR + 1.23 (3) Longest relaxation time (τd) ) Is 100 seconds or more 2. The thermoplastic elastomer composition according to claim 1, which is a composition obtained by a dynamic heat treatment in the presence of an organic peroxide.