JP2891075B2 - Thermoplastic elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention relates to an olefin-based thermoplastic elastomer composition having excellent mechanical properties, capable of substituting a vulcanized rubber, having little oil bleed and good appearance.

[0002]

2. Description of the Related Art Thermoplastic elastomers (hereinafter referred to as "TP")
E ". ) Does not require a vulcanization step and can be processed with a normal thermoplastic resin molding machine. Applications have been developed in a wide range of fields, including automobile parts, home electric parts, and miscellaneous goods. I have. Among them, the olefin-based TPE composition is known from JP-A-48-26838 and the like. However, this composition is inferior to vulcanized rubber in terms of flexibility, tensile strength at break, elongation at break, compression set and the like, and thus has limited applications.
In order to improve these performances, the addition of a mineral oil-based softening agent or a peroxide non-crosslinked hydrocarbon-based rubber-like substance imparts flexibility, and the use of a crosslinking aid increases the degree of crosslinking and improves compression set. Various attempts have been made. (For example, JP-B-56-15740).

However, in these compositions, even if the degree of cross-linking is increased to improve the compression set, the flexibility is reduced, the breaking strength and elongation at break in a tensile test are reduced, or the composition is softened to the surface. It is difficult to obtain an olefin-based TPE composition having an excellent balance of physical properties due to bleeding of the agent.

[0004]

The problem to be solved by the present invention under the present circumstances is that an olefin-based TPE, particularly an olefin-based TP having a low hardness (90 or less in Shore A hardness).
In E, there is little oil bleed, good appearance, flexibility and mechanical properties (especially tensile breaking strength, breaking elongation, compression set) can be substituted for vulcanized rubber, blow moldability, extrusion moldability or injection moldability Good olefin TPE such as
It is to provide a composition.

[0005]

The present inventors have conducted intensive studies to overcome the above-mentioned drawbacks of the conventional method, and as a result, an oil-extended olefin copolymer containing a specific mineral oil-based softener in advance. Using a rubber and a propylene-based polymer resin, a composition obtained by blending a specific ethylene-α-olefin copolymer with a partially cross-linked composition obtained by partially cross-linking this mixture is excellent in flexibility and mechanical properties. And completed the present invention. That is, the present invention relates to an oil-extended olefin containing 20 to 150 parts by weight of a mineral oil-based softener per 100 parts by weight of an olefin-based copolymer rubber having a 100 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) of 120 to 350. Crosslinked composition obtained by dynamically heat-treating a mixture of 40 to 95% by weight of a copolymer rubber (A) and 5 to 60% by weight of a propylene polymer resin (B) in the presence of an organic peroxide Thing 1
A thermoplastic elastomer composition characterized by comprising 5 to 100 parts by weight of an ethylene-α-olefin copolymer (C) having the following properties (C1) to (C4) with respect to 00 parts by weight. Things. (C1) an ethylene content of 50 mol% or more; (C2) an α-olefin having 3 to 10 carbon atoms in a content of 2 to 20 mol%;
3) The density is 0.870-0.915 g / cm ³ , (C4) the maximum melting peak temperature by a differential scanning calorimeter (DSC) is less than 100 ° C., and the calorific value of the melting peak is 0.8 to the total calorific value.
that's all. Hereinafter, the present invention will be described in detail.

In the present invention, the olefin copolymer rubber used in the oil-extended olefin copolymer rubber (A) includes, for example, ethylene-propylene copolymer rubber, ethylene-propylene-nonconjugated diene copolymer rubber. It is an amorphous random elastic copolymer containing an olefin as a main component, such as a united rubber, an ethylene-butene-non-conjugated diene-based copolymer rubber, and a propylene-butadiene-based copolymer rubber. Among these, an ethylene-propylene-nonconjugated diene copolymer rubber is particularly preferred. Examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, with ethylidene norbornene being particularly preferred.

As a more preferred specific example, the propylene content is 10 to 55% by weight, preferably 20 to 40% by weight.
Ethylene-propylene-ethylidene norbornene copolymer rubber (hereinafter referred to as "EPDM") having a non-conjugated diene content of 1 to 30% by weight, preferably 3 to 20% by weight, such as ethylidene norbornene. Part 1
00 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 120 ~
350, preferably 140-300. If the propylene content is less than 10% by weight, flexibility is lost and 55
If it is more than 10% by weight, the mechanical properties tend to decrease. If the content of non-conjugated diene typified by ethylidene norbornene is less than 1%, mechanical properties tend to decrease, and if it exceeds 30% by weight, injection moldability tends to decrease. If the Mooney viscosity at 100 ° C. (ML _{1 + 4} 100 ° C.) is lower than 120, the mechanical properties are lost, and if it is higher than 350, the appearance of the molded article is impaired. However, when EPDM having a Mooney viscosity of 120 to 350 is used, the mechanical properties are large, the tensile strength at break and the elongation at break are dramatically improved, and the crosslinking efficiency is increased. This leads to improved distortion. EPDM manufactured by a known method can be used.

[0008] The mineral oil-based softener used in the present invention is a high-boiling petroleum fraction incorporated for the purpose of improving processability and mechanical properties, and is a paraffinic, naphthenic or aromatic. Although there is a group system or the like, a paraffin system is preferably used. When the amount of the aromatic component is large, the contamination becomes strong, and the use for a transparent product or a bright product is limited, which is not preferable.

The oil-extended olefin-based copolymer rubber (A) is
Mineral oil-based per 100 parts by weight of olefin-based copolymer rubber
20 to 150 parts by weight of a softening agent, preferably 30 to 120 parts by weight
It contains parts by weight. If less than 20 parts by weight,
The fluidity of the refining TPE composition is reduced,
Workability and injection moldability are impaired. On the other hand, 150 parts by weight
When the amount increases, the plasticity increases significantly and the processability deteriorates.
In addition, the performance of the product, such as physical properties, deteriorates.
Not good. And oil-extended olefin copolymer rubber
100 ° C. Mooney viscosity (ML) of (A) _{1 + 4}100 ℃)
Is preferably 30 to 100, more preferably 40 to 9
0. Below 30 the mechanical properties are lost and 100
If it is higher, molding tends to be difficult.

EPDM having a Mooney viscosity of 120 to 350
When a large amount of a mineral oil-based softening agent is blended using olefin, an olefin-based TPE composition capable of simultaneously satisfying improvement of processability by securing flexibility and improvement of fluidity, and improvement of mechanical properties is obtained. I can do it. Generally, a mineral oil-based softener is used as a flowability improver in an olefin-based TPE composition.
When PDM is not used, regardless of the viscosity of EPDM, 40 parts by weight of mineral oil-based softener per 100 parts by weight of EPDM is used.
If it is added in an amount of not less than part by weight, bleeding of the softening agent occurs on the surface of the TPE composition, which is not preferable because contamination and adhesion of the product are observed. However, 100 ° C Mooney viscosity is 120-350
Using oil-extended EPDM in which 20 to 150 parts by weight of a mineral oil-based softening agent is previously blended per 100 parts by weight of EPDM,
There is no bleeding of the softener, no contamination or sticking of the product is observed, and a TPE composition having excellent physical properties such as breaking strength, breaking elongation and compression set can be obtained. Despite the large blending ratio of this mineral oil-based softener, no bleeding of the softener was observed because EPD having a high Mooney viscosity
It is considered that when M is used, the upper limit of the allowable oil extension amount of the mineral oil-based softening agent increases, and the softening agent suitably added in advance is uniformly dispersed in EPDM.

A known method is used for the oil extension method of EPDM. For example, using a device such as a roll or a Banbury mixer, a method of oil-extending by a method of mechanically kneading EPDM and a mineral oil-based softener, or adding a predetermined amount of a mineral oil-based softener to an EPDM solution, and thereafter And a method obtained by removing the solvent by a method such as steam stripping.
Among these, a preferred oil-extension method is a method using an EPDM solution, and the EPDM solution is obtained by polymerization using an EPDM solution.
The operation is easier when a solution is used.

The propylene polymer resin (B) used in the present invention is preferably polypropylene or a copolymer resin of propylene and an α-olefin having 2 or more carbon atoms. Specific examples of the α-olefin having 2 or more carbon atoms include ethylene, 1-butene, 1-pentene, and 3-methyl-
1-butene, 1-hexene, 1-decene, 3-methyl-
There are 1-pentene, 4-methyl-1-pentene, 1-octene and the like. The melt flow rate of these polymer resins is
0.1 to 100 g / 10 min is preferred, and more preferably
It is in the range of 0.5 to 50 g / 10 minutes. If the melt flow rate is smaller than 0.1 g / 10 min or larger than 100 g / 10 min, there is a problem in workability. When the amount of the propylene-based polymer resin (B) in the olefin-based TPE composition of the present invention is less than 5% by weight, the fluidity is reduced, resulting in poor appearance of the molded article. Loses sex.

The organic peroxide which partially cross-links the mixture comprising the oil-extended olefin copolymer rubber (A) and the propylene polymer resin (B) includes 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 5-trimethylcyclohexane, 2,5-
Dimethyl-2,5-di (peroxybenzoyl) hexyne-3, dicumyl peroxide and the like. Of these, odor and scorch are particularly favorable in terms of 2,5-dimethyl-.
2,5-di (t-butylperoxy) hexane is preferred.

The amount of the organic peroxide to be added is 0.005 to 2.0 parts by weight, preferably 0.01 to 0.6 parts by weight based on 100 parts by weight of the total of the oil-extended olefin copolymer rubber (A) and the propylene polymer resin (B). It can be selected in the range of parts by weight. 0.0
If the amount is less than 05 parts by weight, the effect of the crosslinking reaction is small, and if it exceeds 2.0 parts by weight, control of the reaction is difficult, and it is not economically advantageous.

In producing the composition of the present invention, N, N'-m-
Multifunctionality such as phenylene bismaleimide, toluylene bismaleimide, p-quinone dioxime, nitrobenzene, diphenylguanidine, trimethylolpropane, divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate Can be blended. By compounding such a compound, a uniform and mild crosslinking reaction occurs,
It is possible to improve the mechanical properties.

The amount of the crosslinking aid to be added is selected from the range of 0.01 to 4.0 parts by weight based on 100 parts by weight of the total of the oil-extended olefin copolymer rubber (A) and the propylene polymer resin (B). Can be done. Preferably it is 0.05 to 2.0 parts by weight.
If the amount is less than 0.01 part by weight, the effect is hardly exhibited, and if it exceeds 4 parts by weight, it is not economically advantageous.

A partially crosslinked composition is obtained by dynamically heat-treating a mixture comprising an oil-extended olefin-based copolymer rubber (A) and a propylene-based polymer resin (B) in the presence of an organic peroxide. The typical production method will be described below. An oil-extended olefin-based copolymer rubber (A), a propylene-based polymer resin (B), an organic peroxide, and, if necessary, a crosslinking aid are further mixed at a specific ratio and dynamically heat-treated. That is, they are melted and kneaded. As the mixing and kneading apparatus, a conventionally known non-open type Banbury mixer, twin screw extruder, or the like is used.
The kneading temperature may be 150 to 300 ° C. for about 1 to 30 minutes. In the production of this composition, auxiliary materials such as an inorganic filler, an antioxidant, a weathering agent, an antistatic agent, and a coloring agent can be blended as required.

More specifically, the oil-extended olefin-based copolymer rubber (A) and the propylene-based polymer resin (B) and, if necessary, a crosslinking aid and the above-mentioned auxiliary materials are blended in a predetermined ratio, and the mixture is subjected to non-release kneading. 1 using the Banbury mixer
After sufficiently kneading and homogenizing in a temperature range of 50 to 250 ° C., the obtained composition and the organic peroxide are sufficiently blended by an internal mixer such as a tumbler or a super mixer. Next, this blend is dynamically heat-treated at 200 to 300 ° C. using a twin-screw continuous extruder or the like capable of obtaining strong mixing strength, whereby a partially crosslinked composition can be obtained.

Examples of the auxiliary material include the following as specific examples of the antistatic agent. That is,
(A) cationic amines such as primary amine salts, tertiary amines, quaternary ammonium compounds, and pyridine derivatives;
(B) Sulfated oil, soap, sulfated ester oil, sulfated amide oil, sulfated salts of olefins, fatty alcohol sulfates, alkyl sulfates, fatty acid ethyl sulfonates, alkylnaphthalene sulfonates,
Alkylbenzene sulfonate, succinate sulfonate, anionic ones such as phosphate ester salts,
(C) Polyhydric alcohol partial fatty acid ester, fatty alcohol ethylene oxide adduct, fatty acid ethylene oxide adduct, fatty acid amino or fatty acid amide ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide Adducts, ethylene oxide adducts of partial fatty acid esters of polyhydric alcohols, nonionic ones such as polyethylene glycol, and (d) amphoteric ones such as carboxylic acid derivatives and imidazoline derivatives are generally usable. In particular, non-ionic compounds, particularly, polyoxyethylene alkylamines, polyoxyethylene alkylamides, fatty acid esters thereof, and fatty acid esters of glycerin are preferable.

As the above-mentioned antistatic agent, a single kind may be used, or a mixture of two or more kinds may be used. The compounding amount is preferably about 0.03 to 2 parts by weight, more preferably about 0.03 to 2 parts by weight, based on 100 parts by weight of the partially crosslinked composition according to the present invention.
0.04 to 1 part by weight. If the mixing ratio is more than this,
It is not preferable because it oozes out to the surface and decreases the physical properties of the thermoplastic elastomer composition. By the addition of the antistatic agent, a molded article having flexibility and without stickiness can be obtained. In addition, the adhesion of dust and the like due to the absence of stickiness and the bleeding of the softener is reduced, and at the same time, the chargeability, which is the original function of the antistatic agent, is reduced, and the adhesion of dust due to charging is also reduced.

On the other hand, in some cases, slipperiness is desired as the property of the surface of the molded article, but higher fatty acid amides can be used for this purpose. Specific examples of the higher fatty acid amide include lauric amide, balmitic acid amide,
Saturated fatty acid amides such as stearic acid amide and behenic acid amide, unsaturated fatty acid amides such as erucic acid amide, oleic acid amide, bridic acid amide, elaidic acid amide, methylenebisstearic acid amide, methylenebisoleic acid amide, ethylenebisstearin Acid fatty acid amides and bis fatty acid amides such as ethylene bisoleic acid amide are used. Particularly preferred higher fatty acid amides are compounds having a melting point of about 70 ° C to 110 ° C. The amount of the higher fatty acid amide is preferably about 0.03 to 100 parts by weight of the partially crosslinked composition according to the present invention.
２2 parts by weight, more preferably about 0.04 to 1 part by weight.
If the compounding ratio is higher than this, the higher fatty acid amide oozes out onto the surface, and the physical properties of the thermoplastic elastomer composition are deteriorated.

The above-mentioned auxiliary materials can be compounded at the stage of producing the thermoplastic elastomer composition according to the present invention, which will be described later, or at the time of processing or use of the processed product.

The ethylene-α-olefin copolymer (C) used in the present invention has a (C1) ethylene content of at least 50 mol%, more preferably at least 80 mol%.

The ethylene-α-olefin copolymer (C) used in the present invention has a content of (C2) α-olefin having 3 to 10 carbon atoms of 2 to 20 mol%, and 6 to 10 mol%. preferable. When the content of the (C2) α-olefin is 2
If the amount is less than mol%, the processability decreases, and if it exceeds 20 mol%, the heat resistance decreases, which is not preferable.
As the α-olefin, propylene, butene-1,
Penten-1, hexene-1, 4-methyl-pentene-
1, octene-1 or the like alone or in combination. Among these α-olefins, propylene has relatively little improvement effect of the present invention, and α-olefins having 4 or more carbon atoms are preferable, and in particular, butene-1, hexene-1,
4-Methyl-pentene-1, octene-1 and the like are preferable from the viewpoint of easy availability of monomers and the quality of the obtained copolymer.

The ethylene-α-olefin copolymer (C) used in the present invention has a (C3) density of 0.870 to 0.915 g / cm.
³ , preferably 0.895 to 0.915 g / cm ³ , more preferably 0.900 to 0.910 g / cm ³ . 0.870 g / (C3)
If it is less than cm ^3, it is not preferable in terms of surface tackiness,
On the other hand, if the content of (C3) exceeds 0.915 g / cm ³ , the flexibility is undesirably reduced.

The ethylene-α-olefin copolymer (C) used in the present invention is (C4) a differential scanning calorimeter (DSC).
, The highest melting peak is observed in the range of less than 100 ° C, preferably in the range of 70 to 99 ° C, and the heat of fusion of the melting peak is 0.8 or more with respect to the total heat. It is necessary to be. A plurality of melting peaks may be observed within the above temperature range. (C4)
If the maximum melting peak temperature is 100 ° C. or higher, no flexibility is exhibited. (C4) If the heat of fusion at the melting peak is less than 0.8 with respect to the total heat, the balance between heat resistance and flexibility is undesirably reduced.

The ethylene-α- used in the present invention
The olefin copolymer (C) is disclosed in, for example, JP-A-2-77410.
Can be obtained by the method described in Japanese Patent Application Publication No. That is, in a hydrocarbon solvent, (a) V as a transition metal component
O (OR) _n X _3-n (where R is a hydrocarbon group, X is a halogen, and a vanadium compound represented by the formula of 0 <n <3) (b) R ′ _m AlX _3-m ( Here, R ′ is a hydrocarbon group, X is a halogen, an organoaluminum compound represented by 1 <m <3) and (c) a third component represented by the general formula R ″ (C ＝ O) OR ′ ″ (where R '' Is an organic group partially or entirely halogen-substituted with 1 to 20 carbon atoms, and R '' ′ is a hydrocarbon group having 1 to 20 carbon atoms) (hereinafter abbreviated as M). Al / V (molar ratio) is 2.5 or more and M / V (molar ratio) is 1.5 or more when ethylene and an α-olefin having 3 to 10 carbon atoms are copolymerized using Under the catalytic conditions, the molar ratio of ethylene to α-olefin is 35 / 65-60.
/ 40 at a polymerization temperature of 40 ° C. to 80 ° C. in a state in which a hydrocarbon solvent-insoluble polymer (slurry part) and a hydrocarbon solvent-soluble polymer (solution part) coexist. Further, it can be obtained by similarly polymerizing a vanadium compound obtained by reacting vanadium trichloride with an alcohol described in JP-A-60-226514 as the transition metal component (a). .

(C) The ethylene-α-olefin copolymer functions to improve the flowability of the composition obtained by the method of the present invention without substantially impairing the rubbery properties. That is, it functions almost the same as the component (B), and it is preferable that the component (B) and the component (C) are blended complementarily to each other.

In the present invention, the amount of the ethylene-α-olefin copolymer (C) is 5 parts by weight based on 100 parts by weight of the partial crosslink.
-100 parts by weight, preferably 20-60 parts by weight,
If the amount exceeds 100 parts by weight, rubber properties such as flexibility and rebound resilience and heat resistance of the obtained thermoplastic elastomer composition are unfavorably deteriorated.

The thermoplastic elastomer composition according to the present invention may contain an inorganic filler such as calcium carbonate, calcium silicate, clay, kaolin, talc, silica, diatomaceous earth, mica as long as the fluidity and rubber properties are not impaired. powder,
Asbestos, alumina, barium sulfate, aluminum sulfate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass fiber, glass sphere, shirasu balloon, carbon fiber, etc. or coloring agents, such as carbon black, titanium oxide, zinc oxide, Bengal, ultramarine, navy blue, azo pigments, nitroso pigments, lake pigments, phthalocyanine pigments and the like can be blended. In the present invention, known heat-resistant stabilizers such as phenol-based, sulfite-based, phenylalkane-based, phosphite-based or amine-based stabilizers, anti-aging agents, weather-resistant stabilizers, antistatic agents, lubricants such as metal soaps and waxes. And the like can be blended to the extent that they are used in olefin-based plastics or olefin-based copolymer rubbers.

Next, in the present invention, the partially crosslinked composition and (C)
An ethylene-α-olefin copolymer is blended. As a preferable method for uniformly blending, the pellets of the partially crosslinked composition and the pellets of the olefin polymer resin are mixed once in a V-type blender, a tumbler blender, a ribbon blender, a Hensiel mixer or the like, and then an extruder, a mixing roll , Kneading with a kneader or a Banbury mixer. A weathering agent, an antioxidant, a coloring agent and the like may be blended at any stage of the above process.

The thermoplastic elastomer composition according to the present invention can be molded by the equipment used for ordinary thermoplastics, and is suitable for extrusion molding, calender molding and especially injection molding.

The thermoplastic elastomer composition according to the present invention has excellent rubber properties such as heat resistance, weather resistance, tensile properties, flexibility and rebound resilience, since the component (A) is partially crosslinked. In addition, since the fluidity is good, a product having a good appearance without flow marks or sink marks can be obtained when a large-sized thick product is formed.

The thermoplastic elastomer composition according to the present invention can be used for automobile parts such as body panels, bumper parts, side shields, steering wheels, etc., footwear such as shoe soles and sandals, electric covering such as electric wire coating, connectors and cap plugs. Products such as parts, golf club grips, baseball bat grips, swimming pools, swimming fins, recreational articles such as underwater glasses, gaskets, waterproof cloths, garden hoses, belts and the like are conceivable. The thermoplastic elastomer composition according to the present invention is particularly suitable for use in large-thick products such as bumper parts.

[0035]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the test methods used for the sheet forming process and the physical property measurement in these Examples and Comparative Examples are as follows. (1) Mooney viscosity (ML _{1 + 4} 100 ° C): ASTM
D-927-57T. Equation 1 for EPDM
Was calculated.

[0036]

Log (ML ₁ / ML ₂ ) = 0.0066 (△ PHR) ML ₁ : Mooney viscosity of EPDM ML ₂ : Mooney viscosity of oil-extended EPDM ΔPHR: Oil extension amount per 100 parts by weight of EPDM (2) Melt Flow rate (MFR) The method specified in JIS K6760 was used.

(3) Density According to the method specified in JIS K6760. It was measured after annealing for 1 hour in water at 100 ° C.

(4) Differential Scanning Calorimeter (DSC) DSC-7 manufactured by PerkinElmer was used. About 10mg cut out from a 5mm thick sheet made by hot press
Was placed in a sample pan for DSC measurement, preheated at 150 ° C. for 5 minutes, cooled to 40 ° C. at 1 ° C./min, held for 5 minutes, and then heated to 150 ° C. at a rate of 10 ° C./min. A thermogram was obtained.

(5) Extrudability: USV type 25 mmφ extruder manufactured by Union Plastics. Full flight type screw, screw rotation speed 30
rpm. The judgment was performed on the extruded skin using a T-die. The judgment rank is as follows. ：: Excellent △: Good ×: Poor

(6) Oil bleeding property: Injection molded product was 7
It was left in an oven at 0 ° C for 1 hour, and the oil bleeding on the surface of the molded product was visually observed. The judgment rank is as follows. ：: No bleed at all. Δ: Slight bleed. X: There is bleed.

Examples 1-2 (1) Production of Ethylene-Butene-1 Copolymer (C)
A solution in which predetermined ethylene and butene-1 were dissolved in -hexane was continuously supplied at a fixed amount / hour of 80 kg / hour of n-hexane and constant amounts of ethylene and butene-1 respectively. Vanadyl trichloride, ethylaluminum sesquichloride, and n-butyl perchlorcrotonate were continuously supplied at a constant rate / hour from separate supply lines. The temperature inside the reactor was controlled at 40 ° C. or 50 ° C. by circulating cooling water through a jacket attached to the outside of the reactor. The polymerization solution was continuously withdrawn from the top of the reactor so that the inside of the reactor was always full, the polymerization reaction was stopped by adding a small amount of methanol, and after demonomerization and washing with water, the solution was steam-stripped. , Take out the solid polymer,
This was dried under reduced pressure at 80 ° C. to obtain ethylene-butene-1 copolymers (C-1) and (C-2). Table 1 shows the polymerization conditions of each copolymer, the production rate of the copolymer, the density of the obtained copolymer, and the measurement results by MFR and DSC. (2) Production and Evaluation of Thermoplastic Elastomer Composition In a 5% by weight hexane solution of EPDM (ML _{1 + 4} 100 ° C. = 143, propylene content = 30% by weight, iodine value = 10), mineral oil per 100 parts by weight of EPDM 40 parts by weight of a system softening agent (Idemitsu Kosan, Diana Process Oil PW-380) were added, and then 77 parts by weight of oil-extended EPDM (ML _{1 + 4} 100 ° C. = 78) desolvated by steam stripping, Vistanex MML- 100 (polyisobutylene, manufactured by Esso Chemical Co.) 8 parts by weight, polypropylene (MF
R = 12g / 10min, Sumitomo Noblen FL8013) 1
5 parts by weight and 0.3 parts by weight of Sumilizer BM (N, N'-m-phenylenebismaleimide, manufactured by Sumitomo Chemical Co., Ltd.) are kneaded at 170 to 200 ° C. for 7 minutes with a Banbury mixer, and then pelletized using an extruder. A batch was made. Next, 0.1 part by weight of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (hereinafter referred to as "organic peroxide") is used per 100 parts by weight of the master batch.
Using a Henschel mixer for 10
Minutes. This blend was subjected to dynamic heat treatment at 220 ° C. ± 10 ° C. for 70 seconds using a twin-screw kneading extruder capable of obtaining a strong kneading force to obtain a partially crosslinked composition. Forty parts by weight of the ethylene-butene-1 copolymer (C-1) or (C-2) was mixed with 100 parts by weight of the obtained partially crosslinked composition, and molding, evaluation of physical properties, and the like were performed. Table 2 shows the evaluation results.

COMPARATIVE EXAMPLES 1-2 When manufacturing a master batch in Examples 1-2, 77 parts by weight of oil-extended EPDM were added to JSR EP-24 (ML _{1 + 4}
100 ° C. = 70, propylene content = 44% by weight, EPDM having an iodine value = 12, manufactured by Nippon Synthetic Rubber Co., Ltd.) 55 parts by weight and a mineral oil softener PW-380 were replaced with 22 parts by weight as in Example 1. It was carried out. Table 2 shows the evaluation results.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

As described above, according to the present invention, it is possible to provide a thermoplastic elastomer composition having very little oil bleed and having excellent mechanical properties and appearance.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-16554 (JP, A) JP-A-1-247440 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 23/00-23/36

Claims (6)

(57) [Claims] 1. A 100 ° C. Mooney viscosity (ML _{1 + 4} 100
Oil-extended olefin-based copolymer rubber (A) 40 containing 20 to 150 parts by weight of a mineral oil-based softening agent per 100 parts by weight of an olefin-based copolymer rubber having a C of 120 to 350).
To 95% by weight and a propylene polymer resin (B) 5 to 60
% By weight of a partially crosslinked composition obtained by dynamically heat-treating a mixture consisting of
A thermoplastic elastomer composition comprising 5 to 100 parts by weight of an ethylene-α-olefin copolymer (C) having the following properties (C1) to (C4). (C1) an ethylene content of 50 mol% or more; (C2) an α-olefin having 3 to 10 carbon atoms in a content of 2 to 20 mol%;
3) The density is 0.870-0.915 g / cm ³ , (C4) the maximum melting peak temperature by a differential scanning calorimeter (DSC) is less than 100 ° C., and the calorific value of the melting peak is 0.8 to the total calorific value.
that's all. 2. An olefin copolymer rubber comprising ethylene-
The composition according to claim 1, which is a propylene-nonconjugated diene copolymer rubber. 3. An ethylene-propylene-non-conjugated diene copolymer rubber having a propylene content of 10 to 55% by weight,
3. The composition according to claim 2, which is an ethylene-propylene-ethylidene norbornene copolymer rubber having an ethylidene norbornene content of 1 to 30% by weight. 4. An oil-extended olefin-based copolymer rubber (A)
00 ° C Mooney viscosity (ML _{1 + 4} 100 ° C) is 30 ~ ₁
The composition of claim 1 wherein the composition is 00. 5. The composition according to claim 1, wherein the propylene polymer resin (B) is a polypropylene or a propylene-α-olefin copolymer resin. 6. The composition according to claim 1, wherein the mineral oil softener is a paraffin softener.