JPS6383147A - Thermoplastic elastomer - Google Patents

Abstract

PURPOSE:To provide the title elastomer which has excellent low-temperature impact resistance and gives molded products having excellent appearance, by crosslinking a compsn. contg. isoprene rubber, a specified ethylene/alpha-olefin copolymer and a propylene polymer. CONSTITUTION:A thermoplastic elastomer is composed of a crosslinked compsn. obtd. by crosslinking a compsn. comprising 90-10wt% isoprene rubber (A) (e.g., natural rubber or polyisoprene), 10-90wt% (with the total amount of the components A and B being 100wt%) ethylene/alpha-olefin copolymer (B) having a density of 0.860-0.910g/cm<3>, the max. peak temp. of not lower than 100 deg.C as measured by differential scanning calorimetry and a boiling n-hexane insoluble content of not lower than 10wt% (e.g., a copolymer of ethylene with an olefin) and 10-60pts.wt. propylene polymer (C) (with the total amount of the components A, B and C being 100wt%) as essential ingredients (it is preferred that a maleimide crosslinking aid is used together with a crosslinking agent composed of an org. peroxide for the crosslinking of the isoprene rubber). The elastomer has excellent low-temperature impact resistance, gives molded products having excellent appearances and is suitable for use as a material for large-size parts of an automobile bumper.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a new thermoplastic elastomer, and more specifically to crosslinking of a composition comprising rubber, a specific ethylene/α-olefin copolymer, and a propylene polymer. Stone related to thermoplastic elastomer obtained by processing.

<Prior art> In recent years, especially in the automobile industry, electrical industry, etc.
There is an active movement to reduce weight and cost from the viewpoint of resource and energy conservation, and for example, in automobiles, there is a strong push toward using resin for bumpers, instrument panels, and other parts. A similar trend is occurring in the field of household electrical equipment and wire coverings.
In the field of polyolefins, for example, propylene block copolymers with good impact resistance, blend compositions of polypropylene and ethylene/propylene rubber, etc. are being used to replace conventional materials such as plane plates and aluminum, or to replace conventional resins with thin walls. Initially, various methods have been developed for this purpose. Recently, as materials for large parts such as bumpers, particular emphasis has been placed on low-temperature impact resistance and molded product appearance.

As one type of olefin-based thermoplastic elastomer, a thermoplastic blend obtained by dynamically partially curing monoolefin copolymer rubber and polyolefin plastic was published in JP-A-4
No. 8-26838, however, this composition does not necessarily have sufficient impact resistance at low temperatures as a material for large parts. Furthermore, an elastomeric thermoplastic composition comprising a blend of a thermoplastic polyolefin resin and a vulcanized highly unsaturated diene rubber is known from JP-A-52-73950, but this composition may have significantly poor fluidity. Furthermore, when a thick or large product is injection molded, noticeable flow marks occur, making it difficult to obtain a product with a good appearance.

<Problems to be Solved by the Invention> The present invention improves the above-mentioned drawbacks and provides a material with excellent low-temperature impact resistance and appearance of molded products, which is useful in the industrial field including large parts of automobile bumpers. The purpose of the present invention is to provide a thermoplastic elastomer with improved properties.

Means for Solving the Problem> As a result of intensive studies in line with the above objectives, the present inventors have found that
We have discovered that a thermoplastic entomer with excellent properties can be obtained by crosslinking rubber, a specific ethylene/α-olefin copolymer, and a propylene polymer, and based on this we have arrived at the present invention. did.

That is, the present invention provides (JL) isoprene rubber 90-1
0 weight JA%, (b) density 0.860-0.910 t/
ctr? , maximum peak temperature of 100°C or more by differential scanning calorimetry (DSC) and boiling n-hexane insoluble content 1
Ethylene/a-olefin copolymer of 0 weight or more 10
~90 parts by weight (however, the total amount of components (a) and (b) is toOtt) and <c> 10 to 60 parts by weight of propylene polymer (however, components (a), (b) and (c) The present invention provides a thermoplastic elastomer using a crosslinked composition obtained by crosslinking a composition containing (100 parts by weight) as an essential component.

Component (a) used in the present invention is an isoprene rubber.

In addition to natural rubber whose main component is isoprene-based polymers, synthetic rubbers include diene-based rubbers made from butadiene and isoprene, olefin rubbers whose main ingredients are ethylene, propylene, etc., and acrylic esters. Many types of rubber are known, including vinyl rubber made from polysulfide rubber, silicon compound rubber, fluorine compound rubber, and urethane rubber. Ingredients (JL)
It is important to use natural rubber or isoprene-based rubber such as polyisoprene having a similar structure to natural rubber.

The bt ethylene/α-olefin copolymer used in the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms.Specific α-olefins include propylene, butene-1 , 4-methylpentene-1, hexene-1, octene-1, decene-1, dodecene-1, etc. Among these, particularly preferred is propylene having 3 to 6 carbon atoms. , butene-
1, hexene-1 and 4-methylpentene-1. The content of α-olefin in the ethylene/α-olefin copolymer is preferably 5 to 40 mol.

Below, the above (b) ethylene α used in the present invention
- A method for producing an olefin copolymer will be explained.

First, the catalyst system used must contain at least magnesium and
It consists of a solid catalyst component containing titanium and an organoaluminum compound. Examples of the solid catalyst component include metal magnesium, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium chloride, etc., or double salts, double oxides, and carbonates containing a metal selected from silicon, aluminum, and calcium and a magnesium atom. Inorganic solid compounds containing magnesium, such as chlorides or hydroxides, and those obtained by treating or reacting these inorganic solid compounds with oxygen-containing compounds, sulfur-containing compounds, aromatic hydrocarbons, halogen-containing substances, etc. Among them, there are those in which a titanium compound is supported by a known method.

Examples of the above oxygen-containing compounds include organic oxygen-containing compounds such as water, alcohols, phenols, ketones, aldehydes, carboxylic acids, esters, polysiloxanes, and acid amides, and inorganic oxygen-containing compounds such as metal alkoxides and metal oxychlorides. Examples of sulfur-containing compounds include organic sulfur-containing compounds such as thiols and thioethers, and inorganic sulfur compounds such as sulfur dioxide, sulfur trioxide, and sulfuric acid. Aromatic hydrocarbons include various monocyclic and polycyclic aromatic hydrocarbon compounds such as benzene, toluene, xylene, anthracene, and phenanthrene. Halogen-containing substances include chlorine, hydrogen chloride, metal chlorides, and organic Examples include compounds such as halides.

Preferred titanium compounds include titanium halides, alkoxy halides, alkoxides, halogenated oxides, etc., and trivalent titanium compounds. is preferably represented by the general formula TI (oR)nxa=n. Here, R represents an alkyl group having 1 to 20 carbon atoms, an aryl group or an aralkyl group, X represents a halogen atom, and n satisfies 0≦n≦4. For example, titanium tetrachloride, titanium tetrabromide, titanium tetrachloride, monomethoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxymonochlorotitanium, tetramethoxytitanium, monoethoxytrichlorotitanium, jetoxydichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium , monoinpropoxytrichlorotitanium, diisopropoxydichlorotitanium, triinopropoxymonochlorotitanium, tetrainpropoxytitanium, monobutoxytrichlorotitanium, dibutoxydichlorotitanium, monopentoxytrichlorotitanium, monophenoxytrichlorotitanium, diphenoxydichlorotitanium , triphenoxymonochlorotitanium, tetraphenoxytitanium, and the like.

As trivalent titanium compounds, titanium tetrahalides such as titanium tetrachloride and titanium tetrabromide can be combined with hydrogen, aluminum,
Examples include titanium trihalides obtained by reducing titanium or metals from Groups 1 to 2 of the periodic table with organometallic compounds. Also, the general formula Ti (OR)mX, -m (
R is an alkyl group, aryl group, or aralkyl group having 1 to 20 carbon atoms, X is a halogen atom, and m is 0 (m(4
Examples include trivalent titanium compounds obtained by reducing a tetravalent alkoxy titanium halide represented by ) with an organometallic compound of a metal from Group 1 to Group II of the periodic table.

Among these titanium compounds, tetravalent titanium compounds are particularly preferred.

Another example of a catalyst system is a catalyst system in which a reaction product of an organomagnesium compound such as a so-called Grignard reagent and a titanium compound is used as a solid catalyst component, and an organoaluminum compound is combined therewith.

As the organomagnesium compound, for example, the general formula RM
gX.

Organomagnesium compounds such as Rz Mg and RMg (OR) (R is an organic residue having 1 to 20 carbon atoms, X is a halogen atom) and their ether complexes, and these organomagnesium compounds can be further combined with other organometallic compounds For example, those modified by adding various compounds such as organic lithium, organic potassium, organic boron, organic calcium, and organic zinc can be used.

Examples of other catalyst systems include 5i as a solid catalyst component.
Using a solid material obtained by contacting an inorganic oxide such as 02, Al, or 03 with the solid catalyst component containing at least magnesium and titanium, an organoaluminum compound is added to the solid material to form an organic compound to be combined with the solid catalyst component. Specific examples of aluminum compounds include the general formula R3Al s RnAt X5RAIX, , R, A
I(ORλRAI (OR) )
Compounds represented by are preferred, and organic aluminum compounds include triethylaluminum, triimbutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, diethylaluminum ethoxide, ethylaluminum sesquichloride, and mixtures thereof. The amount used is not particularly limited, but it is usually 0.1% for the titanium compound.
It can be used in an amount of 1000 moles.

The copolymerization reaction is carried out in the same manner as a typical olefin polymerization reaction using a Ziegler type catalyst. That is, all reactions are carried out in a gas phase or in the presence of an inert solvent in a state substantially free of oxygen, water, etc., or in the presence of the monomer itself as a solvent. The conditions for copolymerization of ethylene and α-olefin are that the temperature is 20 to 300°C, preferably 40 to 200°C,
The pressure is normal pressure to 70 4-G, preferably 2 Ke.
/cm"・G to 60cm"・G. The molecular weight can be adjusted to some extent by changing conditions such as the copolymerization temperature and the molar ratio of the catalyst, but the molecular weight can be adjusted by adding hydrogen to the polymerization system. It can be carried out effectively.Of course, a two-step or more multi-step polymerization reaction with different polymerization conditions such as hydrogen concentration and polymerization temperature can also be carried out without any problems.

The ethylene/α-olefin copolymer used in the present invention has a density of 0.860 to 0.910 t/err? , the maximum peak temperature (T
m) 100°C or higher and boiling n-hexane insoluble matter (c
It is necessary to titrate properties of 10 g (insoluble matter) or more by weight. Is the density 0.860 f/crr? If less than 0.910171w7 is used, the surface of the molded product will become sticky and the appearance of the molded product will be inferior.If it is more than 0.910171w7, the impact resistance and flexibility of the thermoplastic elastomer will be insufficient. Become.

In addition, Tm is a value that correlates with the crystal form, and this is 100
If it is less than 0.degree. C., the surface of the molded product becomes sticky, and the heat resistance and tensile strength tend to be insufficient, which is not preferable. C
6. The insoluble content is a guideline for the content ratio of the amorphous part and low molecular weight components, and if the insoluble content is less than 10% by weight, the amorphous part and low molecular weight components are too large. This causes a decrease in the strength of the thermoplastic elastomer and causes stickiness on the surface, resulting in poor appearance.

Furthermore, the melt flow rate (MFR1190°C) of the above ethylene/a-olefin copolymer is 0.1 to 30
A range of f/10 m1n is preferable. 0.1 t7
If it is less than 10 m1n, the fluidity of the thermoplastic elastomer may deteriorate, and if it exceeds 30,9710 min, the impact resistance may be poor.

Table (b) DSC of ethylene/a-olefin copolymer
The method for measuring Tm and C6 insoluble content is as follows.

(Measurement method using DSC) Approximately 5w from a 100μm thick film formed by hot press
Weigh a 1i sample, set it on the DSC device, and
After raising the temperature to 70° C. and maintaining 15 ml at that temperature, it is cooled to 0° C. at a cooling rate of 25 C/min. Next, the temperature is raised from this state to 170° C. at a heating rate of 10° C./min, and measurement is performed. Among the peaks that appeared during the temperature increase from 0℃ to 170℃, T is the temperature at the top position of the maximum peak.
Let it be m.

<Method for measuring insoluble Cs> Molding a sheet with a thickness of 200 μm using a heat press, 2
Cut out three sheets of 0 m x 30 ww * and boil them using a double-tube Soxhlet extractor.
Perform 5 hr extraction with 11n-hexane. Take out the n-hexane insoluble matter and vacuum dry (7 hr, under vacuum, 50°C)
After that, calculate the C6 insoluble content using the following formula.

Examples of the propylene polymer (c) used in the present invention include propylene homopolymers, block and random copolymers of propylene and other copolymer components, and mixtures thereof. The copolymerization component is preferably an a-olefin having 2 to 6 carbon atoms, such as ethylene, butene-1, hexene-1,4-methylpentene-1, and the like. The amount of propylene in the copolymer is preferably 50 mole or more.

MFR (230℃) of propylene polymer is 0.1 to 1
00100t710. Preferably, a speed of 1 to 20 f/min is used. If the MFR is less than 0.1 t710m1n, an enstomer with good fluidity and therefore an excellent appearance of the molded product cannot be obtained, and if the MFR is less than 100 f71
If it exceeds 0 m1n, the impact resistance decreases, which is not preferable.

The composition of the above components (a), (b) and (c) used in the present invention is such that (a) is 90 to 10% by weight, preferably 80% by weight, based on the total amount of (&) and (b) being 100% by weight. ~
20% by weight, (b) from 10 to 90% by weight, preferably 2
It is 0 to 80% by weight. Also (a), (b) and (c
) is 100 parts by weight, (a) + (b) is 90
~40i, part, preferably 90 to 50 parts by weight, (c)
is 10 to 60 parts by weight, preferably 10 to 50 parts by weight.

When the weight ratio of (a)/(b) exceeds 90/10, the appearance of the molded product such as the 70-mark and gloss of the thermoplastic elastomer deteriorates, and when the weight ratio of (a)/(b) is less than 10,790, - Impact resistance at low temperatures of 40 to -50°C is undesirable. Also (a) + (b) + (c)
If the amount of (c) in the mixture is less than 10 parts by weight, the moldability of the thermoplastic elastomer tends to decrease and the appearance of the molded product tends to deteriorate, and the heat resistance also decreases.
) exceeds 60 parts by weight, the flexibility of the thermoplastic elastomer is impaired, and both are unfavorable.

In the present invention, a crosslinking agent is used to carry out the crosslinking treatment. Examples of the crosslinking agent include known sulfur, sulfur-containing compounds, organic peroxides, etc., and organic peroxides are preferably used. Examples of organic peroxides include t-butyl hydroperoxide, di-t-butyl peroxide, and t-butyl hydroperoxide.
Butylcumyl peroxide, dicumyl peroxide, 2
．． 5-dimethyl-25-di(t-butylperoxy)hexane, 2,5-dimethyA-2,5-di(t-butylperoxy)hexyne, α,α'-bis(1-butylperoxy) Diimpropylbenzene, α, α′-bis(1
-butylperoxy)diynebutylbenzene, 1.1-
Bis(1-butylperoxy)-3,3,5-trimethylcyclohexane, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide,
Examples include t-butyl peroxybenzoate.

The amount of organic peroxide used is (a) + (b) + (
c) 0.01 to 2, . 0
Part by weight, preferably 0.05 to 0.5 part by weight.

It is preferable to further use a crosslinking aid in the crosslinking treatment.

As a crosslinking aid, p-quinonedioxime, p+P'-
Quinone dioximes such as dibenzoylquinone dioxime, methacrylates such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate, allyls such as diallyl phthalate and triallyl cyanurate, maleimide, N,N'-m-phenylene bis Examples include maleimide-based rubbers such as maleimide, other liquid polybutadiene, divinylbenzene, etc., but when isoprene-based rubber is used as component (a) as in the present invention, maleimide-based crosslinking aids, etc. jt l'l'N,N'-m-phenylene dimaleimide is preferred in terms of crosslinking effect. Furthermore, in this case, only the maleimide-based substance can be used as the crosslinking agent without using any other crosslinking agent.

The amount of the crosslinking aid used is 0.01 to 10 parts by weight, preferably 0.05 to zO parts by weight, based on 100 parts by weight of the total amount of (a) + (b) + (c). Note that several types of specific peroxides or crosslinking aids may be used in combination depending on the purpose.

In the present invention, petroleum-based softeners conventionally used in rubber processing can also be blended and used before or after heat treatment. For example, it is used for the purpose of improving the processability of rubber that is cured by stretching or crosslinking.

Similarly, various fillers such as carbon black, calcium carbonate, silica, metal fibers, and carbon fibers, antioxidants, flame retardants, colorants, ultraviolet absorbers, and the like may be blended as necessary.

In order to produce the thermoplastic elastomer of the present invention, components (a), (b), and (c), a crosslinking agent, and the like are mixed in the composition described above, and then a crosslinking treatment is performed.

Any known technique can be used for the crosslinking treatment.

A typical example is a method of mechanically melting and mixing the above-mentioned blends, - screw and twin screw extruders, Banbury mixer 1.
Crosslinking can be carried out using various kneaders, rolls, etc. The temperature of the melt cross-wire is generally 300°C or less, preferably at a temperature at which the half-life of the crosslinking agent used is 1 min or less, and is usually 100 to 300°C. Further, after adding a crosslinking agent by impregnation or the like, crosslinking may be performed by heat or radiation.

<Effects of the Invention> The thermoplastic elastomer obtained by the present invention is unique in that it mainly combines the following two points: 01) Impact resistance, especially impact resistance at low temperatures (-40 to -50°C) Shows excellent resistance to

2) Because the fluidity is sufficiently high, molding is easy, and the appearance of molded products (flow marks, gloss, etc.) is excellent.

Other properties that are important for practical use include excellent flexibility, heat resistance, and oil resistance, as well as high J strain and resistance to deformation.
Furthermore, the paintability of the molded product is also good.

Since the thermoplastic elastomer of the present invention has the above-mentioned excellent effects, its application range is extremely wide. For example, application examples of the molded product of the present invention include: 1) Automobile pan bars, instrument panels,
Examples include 2) automotive exterior and interior materials, 3) large molded products, 4) sporting goods, 5) hot water pipes, 6) various covers, 7) air ducts, and 8) various packing materials.

<Examples and Comparative Examples> The present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited by these. In addition, the preparation of test pieces and measurement of properties in Examples and Comparative Examples were carried out by the following methods.

(Preparation of test piece) Using an injection molding machine (Is-90) manufactured by Toshiba Machine ■, the cylinder temperature was 20°C and the injection pressure was 1.000 Kg/c.
Each test piece was produced by injection molding using fIP.

(Gel fraction) A test piece measuring 64 m x 13 m ++ x 3 days thick was placed in a 120-mesh all-mesh bag, and extracted with boiling xylene for 6 hours using a double-tube Soxhlet extractor. The insoluble matter was taken out and vacuum dried (60° C., 6 hours), and the boiling xylene insoluble matter (% by weight) was taken as the gel fraction.

(Spiral flow test) Injection molding machine 2 manufactured by Toshiba Machine ■ l5-90 Cylinder temperature: 220℃ Injection pressure crab 1,000Kg/υ2 Mold: Archimedes mold (50℃) (flexural modulus) According to ASTM D790.

(Izotsu impact value)・ According to ASTM D256.

(Dupont impact value) A dart with a hemispherical head with a diameter of an inch is dropped from above a disk-shaped test piece with a diameter of 50 m and a thickness of 2 parrots, and the energy lost in fracture is determined.

(Flowmark) A 200w5X 100mX 3m thick test piece was visually evaluated and scored using a 5-point system (best 5).

(glossy) According to ASTM D 523 (incidence angle 60°).

(Paintability) Urethane paint was applied to a test piece measuring 200 mm x 100 m x 31 + Ill thickness, and 11 scratches were made on the - side with a razor blade at intervals of 111 I + in length and width to form 100 substrates. It is expressed by the number of base marks that remain after making the marks, pressing adhesive tape on top of the marks, and then removing the coating film.

Examples 1 to 9, Comparative Examples 1 to 6 The components (a), (b), and (c), organic peroxide, crosslinking aid, and petroleum softener used were as follows.

Component (a): Polyisoprene (density α91f/crI?, Mooney viscosity (ML144)
．． Component (b): (B) Ethylene-butene-1 copolymer from substantially anhydrous magnesium chloride, 1,2-dichloroethane and titanium tetrachloride Ethylene and butene-1 were copolymerized using the obtained solid catalyst component and a catalyst consisting of triethylaluminum to obtain an ethylene/butene-1 copolymer.

The butene-1 content of this ethylene-butene-1 copolymer was 12 molt, and the properties were as follows: density
0.896 f10r? Tm 12
0°C C6 insoluble content 74% by weight MFRO, 99710mln (c) Ethylene-propylene copolymer Ethylene is produced using a solid catalyst component obtained from substantially anhydrous magnesium chloride, anthracene and titanium tetrachloride and a catalyst consisting of triethylaluminum. and propylene were copolymerized to obtain an ethylene-propylene copolymer. The propylene content of this ethylene-propylene copolymer was 13 molt, and the properties were as follows: Density
0.9009/7F+3Tm 121℃ C6 insoluble content 77% by weight 'MFR1,OS'/10m1n Component (c): ■) Polypropylene (MFR4, Of/10mtn; Product name: 8 stone Polypro J630, manufactured by Nippon Petrochemical ■) Organic Peroxide: (Odor α, α′-bis(1-butyloxy)-
m-diinpropylbenzene (product name: Perbutyl P, manufactured by NOF ■) Crosslinking aid: ■ N,N'-m-phenylene dimaleimide (product name:
Petroleum-based softener (manufactured by Parnock PM, Ohmukai Shinko Kagaku Kogyo ■): (G) Naphthenic process oil The various raw materials listed above were mixed in the composition shown in the table, and mixed in a nitrogen atmosphere using a Bamba IJ mixer. 180℃
×10 m1n) was performed. Regarding Example 4, after kneading raw materials other than petroleum softener (G) under the above conditions,
@) was added and crosstalk was further performed for 5 m1n.

The resulting mixture was rolled into a sheet using rolls, and then pellets were produced using a sheet cutter. Using this, a test piece was prepared by the method described above, and the physical properties were evaluated. The results are shown in the table.

Comparative Examples 7 to 9 The following various ethylene polymers were used in place of the (B) ethylene-butene-1 copolymer used as component (b) in Example 6, and all other conditions were the same as in Example 6. went. The results are shown in the table.

Component (b): αD ethylene-propylene copolymer rubber (Mooney viscosity (ML1+4,100°C) 24, MFRl, 9971
0m1n; Product name: Epozp, manufactured by Nippon Synthetic Rubber ■) (I) Ethylene-propylene-nonconjugated diene copolymer rubber (MF RO, 2f/10 min; Product name: EP57P, manufactured by Nippon Synthetic Rubber ■) (J) Straight Chain low density polyethylene (density 0.922?/at?, Tm 122°C, C6 insoluble content 96% by weight, MF R1,0f710 min)
Example 10.11, Comparative Example 10 The following were used as the component (a), the above CB) ethylene-butene-1 copolymer was used as the component (b), and all others were as in Examples 1 to 9. I did the same. The results are shown in the table.

(6) Natural rubber (density 0.92 F//crr?, Mooney viscosity (ML)
1+4.100C) 96; Malaysian SMR-L) Table symbol explanation A: Polyisoprene (IR2200) B: Ethylene-butene-1 copolymer C: Ethylene-propylene copolymer D: Voripropylene (8-stone polypro J630) E:α,
α'-bis(1-butylperoxy>, -diinpropylbenzene (/: -phthyl p) F: N, N'-m-phenylene dimaleimide (Parnock PM) G: Naphthenic process oil H: Ethylene/propylene Copolymer rubber (EP02P)
Process: Ethylene-propylene-nonconjugated die/copolymer rubber (EP 57 P) J: Linear low density polyethylene: Natural rubber (SMR-L) As is clear from Tables 1 and 2, component (a) , (b
The thermoplastic elastomers of Examples 1 to 11 in which ) and (c) are within the scope of the present invention all have low-temperature impact values and 7
Excellent molded product appearance represented by 0-mark and gloss. On the other hand, Comparative Examples 1 to 1 which are outside the scope of the present invention
It can be seen that No. 10 is inferior in terms of the above performance.

Patent applicant: Japan Petrochemical Co., Ltd. Agent: Patent Attorney Takehiko Saito 1:,’,,”,::’,.

I Ryoji Yosera/Ee Part

Claims (1)

[Claims] 1. (a) 90 to 10% by weight of isoprene rubber; (b)
Ethylene/α-olefin copolymer 10 to 10 with a density of 0.860 to 0.910 g/cm^3, a maximum peak temperature of 100°C or more by differential scanning calorimetry (DSC), and a boiling n-hexane insoluble content of 10% by weight or more 90% by weight (however, the total amount of components (a) and (b) is 100% by weight) and (c) 10 to 60 parts by weight of propylene polymer (however, components (a), (b) and (c) ) A thermoplastic elastomer using a crosslinked composition obtained by crosslinking a composition containing (the total amount of) is 100 parts by weight. 2. The thermoplastic elastomer according to claim 1, wherein the isoprene rubber of component (a) is natural rubber or polyisoprene. 3. In the presence of a catalyst consisting of a solid catalyst component containing at least magnesium and titanium and an organoaluminum compound, the ethylene/α-olefin copolymer of component (b) is mixed with ethylene and α-olefin having 3 to 12 carbon atoms. - The thermoplastic elastomer according to claim 1, which is a copolymer obtained by polymerizing with an olefin. 4. The thermoplastic elastomer according to claim 1 or 2, wherein a crosslinking agent containing at least N,N'-m-phenylene dimaleimide is used in the crosslinking treatment. 5. The thermoplastic elastomer according to claim 1, which contains a petroleum softener as a component other than the components (a), (b) and (c).