JP3399384B2 - Thermoplastic elastomer composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition. More specifically, it relates to a thermoplastic elastomer composition having an excellent balance between mechanical properties such as flexibility and elastic recovery and molding processability.

[0002]

2. Description of the Related Art An olefin-based thermoplastic elastomer obtained by dynamically heat-treating an ethylene-based copolymer rubber and an olefin-based resin in the presence of a cross-linking agent does not require a vulcanization step and is a normal thermoplastic resin. It has the advantage that the molding method of, for example, injection molding, profile extrusion molding, calendering, blow molding and the like can be adopted. However,
Such an olefin-based thermoplastic elastomer has a disadvantage that it is inferior in elastic recovery property as compared with a vulcanized rubber. Conventionally, in order to make up for these disadvantages, the crosslinking density of the ethylene copolymer rubber has been improved, and the Mooney of the ethylene copolymer rubber has been raised. Although elastic recovery is improved by these methods, the fluidity of the resulting thermoplastic elastomer composition is significantly reduced. There is also a method of adding a peroxide-decomposable olefin-based rubber in order to improve the moldability, but in this case, the elastic recovery is lowered. On the other hand, when dynamically heat-treated in the presence of a crosslinking agent, the fluidity of the thermoplastic elastomer composition can be improved by adding a large amount of a mineral oil-based softening agent, but the moldability deteriorates. However, there is a problem that the appearance of the extruded product deteriorates. As described above, it has been difficult for the olefinic thermoplastic elastomer obtained by the conventional method to obtain a balance between elastic recovery and molding processability.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is a thermoplastic elastomer having a good balance between mechanical properties such as flexibility and elastic recovery and molding processability. The purpose is to provide.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that an oil containing an ethylene copolymer rubber having a specific intrinsic viscosity [η] and a mineral oil softener. The present invention was completed by finding that the intended thermoplastic elastomer composition can be obtained by dynamically heat-treating an expanded ethylene copolymer rubber and an olefin resin in the presence of a crosslinking agent. That is, the present invention has the following configurations. [1] (a) An oil-extended ethylene-based copolymer containing an ethylene-based copolymer rubber having an intrinsic viscosity [η] of 4.3 to 6.8 dl / g measured at 135 ° C. in a decalin solvent and a mineral oil-based softening agent Heat obtained by dynamically heat-treating a polymer composition containing a polymerized rubber and (b) olefin resin in an amount of 70% by weight or more based on 100% by weight of a total of polymer components in the presence of a crosslinking agent. Plastic elastomer composition. [2] (a) The oil-extended ethylene copolymer rubber comprises 100 parts by weight of the ethylene copolymer rubber and the mineral oil softener 2
The thermoplastic elastomer composition according to the above [1], which comprises 0 to 300 parts by weight. [3] The weight ratio ((a) / (b)) of (b) oil-extended ethylene copolymer rubber and (b) olefin resin is 20/8.
The thermoplastic elastomer composition according to the above [1] or [2], which is 0 to 95/5. [4] (a) The oil-extended ethylene-based copolymer rubber is obtained by desolventizing a mixed solution containing the ethylene-based copolymer rubber and the mineral oil-based softener as described above [1] to [3. ] The thermoplastic elastomer composition in any one of these. The present invention will be described in detail below, and other objects, advantages and effects of the present invention will be apparent.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The oil-extended ethylene copolymer rubber (a) which is a component of the thermoplastic elastomer composition of the present invention is
Intrinsic viscosity [η] measured at 135 ° C in decalin solvent
Of 4.3 to 6.8 dl / g and an ethylene-based copolymer rubber and a mineral oil-based softening agent.

As the above ethylene-based copolymer rubber, ethylene and α- having 3 or more carbon atoms, preferably 3 to 8 carbon atoms are used.
There may be mentioned a random copolymer obtained by copolymerizing an olefin and a non-conjugated diene. Examples of the α-olefin having 3 or more carbon atoms which is copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene. α
-The olefins may be used alone or in combination of two or more. Further, as the non-conjugated diene to be copolymerized, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene,
Examples thereof include ethylidene norbornene, 5-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 6-methyl-1,5-heptadiene, and methyl-1,6-octadiene. It is also possible to impart a branched structure to the ethylene random copolymer by a known method. Preferred dienes for imparting a branched structure include 1,5-hexadiene, 1,7-octadiene,
1,9-decadiene, norbornadiene and the like can be mentioned. These non-conjugated dienes may be used alone or in combination of two or more. From the viewpoint of maintaining the mechanical strength and flexibility of the ethylene random copolymer rubber, these ethylene random copolymers are preferably 50/50 to 95/5 in molar ratio of ethylene / α-olefin, and more preferably Is preferably copolymerized at 60/40 to 90/10. The content of the non-conjugated diene is preferably 12% by weight or less, more preferably 1 to 10% by weight.

The intrinsic viscosity of ethylene copolymer rubber is a value measured at a temperature of 135 ° C. in a decalin solvent,
4.3-6.8 dl / g, preferably 4.3-6.0 d
1 / g, and more preferably 4.4 to 5.7 dl / g. If the intrinsic viscosity is less than 4.3 dl / g, the elastic recovery is impaired, and if it exceeds 6.8 dl / g, the workability during molding is impaired.

(A) The mineral oil-based softening agent contained in the oil-extended ethylene-based copolymer rubber is used for imparting moldability and flexibility and improving the product appearance. As a mineral oil softener, aromatic, naphthenic,
Paraffin-based, etc. can be mentioned, but paraffin-based,
Naphthenes are preferred. The blending amount of the mineral oil-based softening agent is usually 20 with respect to 100 parts by weight of the ethylene-based copolymer rubber, in consideration of the molding processability, flexibility, heat resistance and strength of the thermoplastic elastomer composition of the present invention. ~ 30
0 to 30 parts by weight, preferably 50 to 1 parts by weight
50 parts by weight is more preferable, and 80 to 150 parts by weight is the most preferable.

The (a) oil-extended ethylene-based copolymer rubber of the present invention can be prepared by removing the solvent from a mixed solution containing the ethylene-based copolymer rubber and the mineral oil-based softening agent. The method is not particularly limited, but as a preferred method, a predetermined amount of a mineral oil-based softening agent is added to an ethylene-based copolymer rubber mixture obtained by polymerization, and after mixing, a steam stripping method, a flash method, or the like. A method of removing the solvent can be mentioned. After the polymerization, the obtained ethylene-based copolymer rubber is uniformly dissolved in a good solvent such as a hydrocarbon solvent such as benzene, toluene, xylene, hexane, heptane, and cyclohexane, a halogenated hydrocarbon solvent such as chlorobenzene, and the like. None, add a predetermined amount of mineral oil softener,
After mixing, the solvent may be removed by a method such as a steam stripping method or a flash method. Further, the oil-extension of the ethylene-based copolymer rubber can be carried out by using an apparatus used for the oil-extension of ordinary rubber such as a Banbury mixer, a pressure kneader or a roll. However, since the rubber has a high molecular weight before being oil-extended, it is difficult to uniformly disperse the mineral oil-based softening agent in the ethylene-based copolymer rubber.

When a mineral oil-based softening agent is added to the mixed solution of ethylene copolymer rubber as described above, the softening agent is sufficiently and uniformly dispersed in the rubber, so that the softening agent bleeds from the surface of the molded article. It is preferable because it will not be out. The ethylene-based copolymer rubber can be polymerized by a known polymerization method, for example, in the presence of a vanadium-based, titanium-based, or metallocene-based catalyst. Is practically preferable.

The ethylene copolymer rubber may be used alone or in combination.
Can be used in combination of two or more kinds. In addition,
As ethylene copolymer rubber, water of ethylene copolymer rubber is used.
Some of the elementary atoms are halogen atoms such as chlorine and bromine atoms.
Substituted halogenated ethylene copolymer rubber or vinyl chloride
Nyl, vinyl acetate, (meth) acrylic acid or its derivatives
(For example, methyl (meth) acrylate, glycidyl (meth
A) acrylate, (meth) acrylamide, etc.), male
In-acid or its derivatives (eg maleic anhydride, maleic acid)
Amide, dimethyl maleate, etc.), conjugated dienes (eg
Unsaturated compounds such as tadiene, isoprene, chloroprene, etc.)
Graft-Modified Ethylene Copolymer with Graft Polymerization of Nomer
Coalescence can also be used. (B) Oil-extended ethylene-based
The shape of polymerized rubber is either bale, crumb or pellets.
Any shape may be used. Such (a) oil-extended ethylene-based
Polymerized rubber is used to control the flexibility and elastic recovery of the resulting composition.
From the viewpoint, it is preferably amorphous or low crystalline. Conclusion
Crystallinity is related to density, and generally its crystallinity is simpler.
Can be replaced by density. (B) Oil exhibition of the present invention
The density of the ethylene copolymer rubber is 0.89 g /
cm ³The following is preferable.

The olefin resin as the component (b) is not particularly limited, but examples thereof include ethylene homopolymers, crystalline ethylene copolymers containing 90 mol% or more of ethylene, and crystalline propylene homopolymers. , Propylene 90
A crystalline propylene copolymer containing at least mol% is preferable. Specifically, high density polyethylene, low density polyethylene, ethylene / 1-butene copolymer, ethylene / 1
-Crystalline ethylene polymers such as hexene copolymer and ethylene / 1-octene copolymer; isotactic polypropylene, propylene / ethylene copolymer, propylene /
1-butene copolymer, propylene / 1-pentene copolymer, propylene / 3-methyl-1-butene copolymer, propylene / 1-hexene copolymer, propylene / 3-methyl-1-pentene copolymer , Propylene / 4-methyl-1-pentene copolymer, propylene / 3-ethyl-1
-Pentene copolymer, propylene / 1-octene copolymer, propylene / 1-decene copolymer, propylene / 1
-Undecene copolymer, propylene / 1-butene / ethylene terpolymer, propylene / 1-hexene / 1-octene terpolymer, propylene / 1-hexene-4-
A crystalline propylene polymer whose main component is a propylene component such as a methyl-1-pentene terpolymer.

The weight ratio of the (a) oil-extended ethylene copolymer rubber and the (b) olefin resin ((a) /
(B)) is usually 20/80 to 95/5, preferably 30/70 to 90/10, more preferably 40 /.
It is 60 to 90/10. When the ratio of (a) the oil-extended ethylene copolymer rubber and (b) the olefin resin is within the above range, the thermoplastic elastomer composition of the present invention has mechanical properties such as flexibility and elastic recovery and molding processing. In addition to being excellent in balance with the property, it becomes possible to have an excellent product appearance.

The cross-linking agent used in the present invention is one usually used for cross-linking ethylene copolymer rubber such as EPM or EPDM, for example, sulfur, sulfur compounds, organic peroxides, phenol resin cross-linking agents, quinoids. A cross-linking agent, a metal acrylate cross-linking agent, a bismaleimide cross-linking agent and the like are used. Hereinafter, these crosslinking agents will be sequentially described.

(1) Sulfur and Sulfur Compounds The sulfur and sulfur compounds used in the present invention may be those generally manufactured and sold for vulcanization of rubber. Examples of the sulfur may include powdered sulfur, white sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur and insoluble sulfur. Further, as the sulfur compound, sulfur chloride; sulfur dichloride; molyforne disulfide; alkylphenol disulfide; thioureas such as dibutylthiourea; mercaptobenzothiazole, dibenzothiazyl disulfide, 2- (4-morpholinodithio) benzothiazole, etc. Examples thereof include dithiocarbamates such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, and sodium dimethyldithiocarbamate.

(2) Organic peroxide Examples of the organic peroxide include dicumyl peroxide,
Di-tert-butyl peroxide, 2,5-dimethyl-2,5
-Di (tertiary butylperoxy) hexane, 2,5-dimethyl-di (tertiary butylperoxy) hexyne-3,1,
3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,3
5-trimethylcyclohexane, n-butyl-4,4-
Bis (tertiary butylperoxy) valerade, benzoyl peroxide, p-chlorobenzoyl peroxide,
2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl peroxide and the like can be mentioned. Among these organic peroxides, it is preferable that the decomposition reaction is mild and the crosslinking reaction proceeds after the rubber and the resin component are mixed more uniformly. An organic peroxide having a mild decomposition reaction can be represented by using, for example, a one-minute half-life temperature as an index, and this one-minute half-life temperature is sufficiently high,
It is preferably 150 ° C. or higher. As such an organic peroxide, for example, 2,5-dimethyl-2,5-di (3rd
Butylperoxy) -hexyne-3,2,5-dimethyl-2,5-di (tertiary butylperoxy) hexane, 1,
3-bis (tertiary butylperoxyisopropyl) benzene may be mentioned. 2,5-Dimethyl-, which has a particularly high decomposition temperature
Most preferred is the use of 2,5-di (tertiary butylperoxy) -hexyne-3.

If a suitable crosslinking aid is present together with an organic peroxide as a crosslinking agent, a uniform and mild crosslinking reaction can be expected. As the crosslinking aid, sulfur, p-quinone dioxime, p, p'-dibenzoylquinone dioxime, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene dimethacrylate, polyethylene glycol dimethacrylate, Trimethylolpropane trimethacrylate, diarylphalates, diarylphthalates, tetraaryloxyethanes, triarylcyanurates, diarylphthalates, tetraaryloxyethanes, triarylcyanurates,
N, N-m-phenylene bismaleimide, maleic anhydride, divinylbenzene, zinc di (meth) acrylate, aluminum tri (meth) acrylate, magnesium di (meth) acrylate, etc. are used. Among them, N, N-m-phenylene bismaleimide, p, p'-dibenzoylquinone dioxime and divinylbenzene are preferable. These are 1
They may be used alone or in combination of two or more.

The mixing ratio of the organic peroxide, from the viewpoint of performing uniform and mild partially crosslinked, relative to the total amount 100 parts by weight of the ethylene copolymer rubber and o olefin-based resin component, preferably 0. 02 to 1.5 parts by weight, more preferably 0.05 to 1.0 parts by weight. The mixing ratio of the crosslinking aid, based on the total amount of 100 parts by weight of the ethylene copolymer rubber and o olefin-based resin is preferably 3 parts by weight or less, more preferably 0.2 to 2 parts by weight. When the compounding ratio is within this range, the thermoplastic elastomer composition of the present invention maintains the homogeneity of the phase structure (sea-island structure) and the moldability associated therewith. In addition, excessive use may remain in the thermoplastic elastomer composition as an unreacted monomer, and the physical properties may change due to the heat history during the molding process.

(3) Phenolic Resin-Based Crosslinking Agent A preferred phenolic resin-based crosslinking agent is a compound represented by the following general formula.

[0020]

[Chemical 1]

Here, m is an integer of 0 to 10 and X and Y are hydroxyl groups or halogen atoms, which may be the same or different. R is a saturated hydrocarbon group having 1 to 15 carbon atoms. The above compounds are described, for example, in US Pat.
It is commonly used as a cross-linking agent for rubbers, as described in the specifications of No. 40 and No. 3709840. And this crosslinking agent, in the presence of an alkali catalyst,
It can be produced by polycondensing a substituted phenol and an aldehyde. The blending ratio of the above-mentioned phenol-based cross-linking agent is an ethylene-based copolymer rubber in order to make the degree of partial cross-linking of the thermoplastic elastomer composition of the present invention appropriate, oil resistance, shape recovery, and good flexibility. It is preferably 0.1 based on 100 parts by weight of the olefin resin.
10 to 10 parts by weight, more preferably 0.3 to 5 parts by weight, still more preferably 0.4 to 2 parts by weight. The phenolic cross-linking agent can be used alone, but can also be used in combination with a cross-linking accelerator in order to control the cross-linking speed. As the crosslinking accelerator, a metal halide of stannous chloride, ferric chloride, an organic halide such as chlorinated polypropylene, brominated polypropylene, brominated butyl rubber, chloroprene rubber can be used. Further, a metal oxide such as zinc oxide or a dispersant such as stearic acid may be used in combination.

(4) Quinoid-based cross-linking agent A preferred quinoid-based cross-linking agent is a derivative of p-quinone dioxime. Specifically, p-benzoquinone dioxime, p-dibenzoyl quinone diamide and the like. The mixing ratio of the quinoid-based cross-linking agent is preferably 0.2 to 10 parts by weight, based on the total 100 parts by weight of the ethylene-based copolymer rubber and the olefin-based resin, for the same reason as in the case of the phenol-based cross-linking agent described above. , More preferably 0.5 to 7 parts by weight, still more preferably 0.8 to 3 parts by weight. The cross-linking agent can be used alone, but a cross-linking accelerator can be used in combination for controlling the cross-linking speed. As the crosslinking accelerator, an oxidizing agent such as red lead, dibenzothiazoyl sulfide or tetrachlorobenzoquinone can be used. Further, a metal oxide such as zinc oxide or a dispersant such as stearic acid may be used.

(5) Acrylic acid metal salt-based cross-linking agent The acrylic acid metal salt-based cross-linking agent is a metal salt of zinc or calcium such as acrylic acid or methacrylic acid. Usually, it is obtained, for example, by reacting zinc oxide or zinc carbonate with methacrylic acid. Specifically, zinc dimethacrylate, calcium dimethacrylate, magnesium dimethacrylate,
Examples include monohydroxyaluminum dimethacrylate, aluminum trimethacrylate, calcium diacrylate, magnesium diacrylate, monohydroxyaluminum diacrylate and aluminum triacrylate.
The preferable amount of the metal acrylate-based cross-linking agent in the case of dynamically performing heat treatment with the metal acrylate-based cross-linking agent as a main component is 100 parts by weight of the total of the ethylene-based copolymer rubber and the olefin-based resin. It is preferably 1 to 20 parts by weight, more preferably 4 to 12 parts by weight. (6) Bismaleimide-based cross-linking agent A bismaleimide-based cross-linking agent usually used is
It is N, N'-m-phenylene bismaleimide. The bismaleimide-based cross-linking agent is usually used as a cross-linking aid for organic peroxide cross-linking, but it is known that the cross-linking reaction occurs even when used alone. The preferred blending ratio of the bismaleimide-based cross-linking agent is 0.05 to 10 relative to 100 parts by weight of the total of the ethylene-based copolymer rubber and the olefin-based resin.
Parts by weight, more preferably 0.1 to 5 parts by weight, still more preferably 0.2 to 2 parts by weight.

The thermoplastic elastomer composition of the present invention contains an antioxidant, an antistatic agent, a weathering stabilizer in an amount that does not substantially impair the characteristics of the composition, depending on the application.
UV absorbers, lubricants, antiblocking agents, sealability improving agents, crystal nucleating agents, flame retardants, antibacterial agents, fungicides, tackifiers, softeners, plasticizers, colorants (titanium oxide, carbon black) Etc.), filler (glass fiber, carbon fiber, metal fiber, aramid fiber, glass beads, mica, calcium carbonate, potassium titanate whiskers, talc, barium sulfate, glass flakes, fluororesin, etc.), etc. it can. In addition, rubbery polymers (butyl rubber and N
BR, etc.), thermoplastic resin, thermoplastic elastomer (low crystalline propylene-based polymer, hydrogenated diene-based polymer, etc.) and the like can be appropriately blended. These polymers are
The component (a) and the component (b) may be blended during the dynamic heat treatment in the presence of the crosslinking agent, or the component (a) and the component (b) may be dynamically added in the presence of the crosslinking agent. You may mix after heat-processing. The blending amount of the polymer component other than the component (a) and the component (b) is less than 30% by weight based on 100% by weight of the total of the polymer components. Further, the above-mentioned mineral oil-based softening agent may be additionally added to the thermoplastic elastomer composition of the present invention, for example, at the stage of dynamically heat-treating, as long as it does not cause bleeding.

The thermoplastic elastomer composition of the present invention comprises
(B) the resulting oil-extended ethylene-based copolymer rubber and (b) O olefin based <br/> resin is subjected to dynamic heat treatment in the presence of the crosslinking agent. In the present invention, dynamically performing heat treatment means that the melt-kneading / dispersion of the component (a) and the component (b) and the crosslinking reaction of the component (a) are simultaneously performed in the presence of the crosslinking agent. By carrying out such an operation, an olefinic thermoplastic elastomer composition having a sea-island structure in which the partially or completely crosslinked (a) component floats in the (b) component is obtained.
The temperature condition of the dynamic heat treatment is preferably in the range of 150 ° C to 250 ° C in which the melting of the component (b) and the crosslinking reaction are well balanced.

The apparatus used for the above-mentioned dynamic heat treatment is a batch type kneader such as a pressure kneader, a Banbury mixer, a Brabender, a single-screw extruder, a twin-screw extruder,
A continuous kneader such as a continuous kneader and a feeder ruder, and a combination of these devices. For example, the thermoplastic elastomer composition of the present invention can be obtained by the devices and methods described below. The components (a) and (b) are kneaded by the batch-type kneader, and the temperature is adjusted to sufficiently melt the components (a) and (b). Then, a crosslinking agent is added and heat treatment is performed dynamically. Using the batch type kneader, the components (a) and (b) are sufficiently blended at a temperature at which the components (a) and (b) are sufficiently melted (first stage). Using a continuous kneading machine, the blended product in the first stage and the cross-linking agent are charged and the heat treatment is carried out dynamically (second stage). The component (a), the component (b) and the cross-linking agent are charged into a continuous kneader and dynamically heat-treated. In the above, the additional mineral oil-based softening agent, various additives and the like may be added at any stage. Any of the above methods may be used as long as they do not exceed the gist of the present invention, in which the heat treatment is carried out dynamically in the presence of a crosslinking agent in the molten state of the components (a) and (b). It is not limited.

[0027]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, parts and% are based on weight unless otherwise specified. Various measurements in the examples were carried out by the following methods.

(1) JIS A hardness Measured according to JIS K6301. (2) Elastic recovery The compression set was used as an index of elastic recovery. The measurement conditions were as follows: compression set at 70 ° C. for 22 hours and 25% compression. The smaller the compression set, the better the elastic recovery. (3) Tensile strength and maximum elongation Measured according to JIS K6301. (4) Fluidity MFR (melt flow rate) was measured under the following conditions and used as a measure of fluidity. Temperature: 230 ° C., load: 10 kg (5) Moldability Injection moldability and extrusion moldability were evaluated. Injection moldability: A flat plate was injection molded with a 6.5 ounce injection molding machine manufactured by Japan Steel Works. The sink mark, the burn, and the mold transfer property of the molded product were evaluated in the following three stages. ◯: There is no sink mark or burn, and the die mirror surface is sufficiently transferred. Δ: A phenomenon such as a slight sink mark, a burn, or insufficient mold transfer occurred. X: Any serious phenomenon such as sink mark, burn, or insufficient mold transfer has occurred. Extrudability: 30 mm extruder manufactured by Nakatani Machinery Co., Ltd.
A die was attached to form a sheet, and the surface skin was evaluated in the following three stages. ◯: The surface is sufficiently smooth. Δ: The surface is slightly rough or sharkskin is generated. X: Melt fracture has occurred.

Each component used in this example and comparative examples will be described. (1) Oil-extended ethylene-propylene-diene random copolymer rubber using the ethylene-based copolymer rubber, a mineral oil-based softening agent and the oil-extended amount thereof are shown in Table 1 below.

[0030]

[Table 1] In the diene column, ENB and DCP represent the following compounds, respectively. ENB: ethylidene norbornene DCP: dicyclopentadiene oil extension (PHR) means the blending amount (parts by weight) of a mineral oil-based softening agent with respect to 100 parts by weight of rubber.

The oil-extended ethylene / propylene / diene random copolymer rubbers (EP-1 to EP-6) shown in Table 1 above were prepared by the following method. A separable flask having an internal volume of 3 liters, which had been previously purged with nitrogen, was charged with 2 liters of dehydrated and purified n-hexane, and ethylene gas, propylene gas and hydrogen gas refined through a molecular sieve were flown at a flow rate of 6/4/1 (volume ratio). The mixture was fed in the gas phase at a ratio and dissolved for 10 minutes at room temperature with stirring. Then, the diene component, aluminum sesquichloride (Al
Polymerization was initiated by charging 5 mmol of Et _1.5 Cl _1.5 ) and 0.1 mmol of vanadium oxytrichloride (VOCl ₃ ). While feeding ethylene gas, propylene gas and hydrogen gas in a gas phase, the reaction temperature was adjusted to 20 ° C. to continue the polymerization reaction. Twenty minutes after the initiation of the polymerization, the catalyst was deactivated with isopropyl alcohol purified by molecular sieves to terminate the polymerization. After blending a predetermined amount of mineral oil-based softener to the obtained copolymer solution,
After adding these components to methanol for precipitation, 1
It was dried with a hot roll of 00 ° C. to obtain an oil-extended copolymer rubber.

[0032] (2) Oh olefin resin PP-1: polypropylene [Japan Polychem Corporation, trade name: MA-03] PP-2: random polypropylene [Japan Polychem Corporation, trade name: MG-03A] PP-3: block Polypropylene [Product name: BC-03C manufactured by Nippon Polychem] PP-4: Random polypropylene [Product name: EX-6 manufactured by Japan Polychem] PE: Linear low density polyethylene [Product name: UJ370 manufactured by Japan Polychem] ( 3) Mineral oil softener oil-1: Paraffin oil [made by Idemitsu Kosan Co., Ltd., trade name:
PW-380] oil-2: naphthenic oil [made by Idemitsu Kosan Co., Ltd., trade name: N
S-100] (4) Cross-linking agent Cross-linking agent 1: 2,5-dimethyl-2,5-di (tertiary butylperoxy) -hexyne-3 [Nippon Yushi Co., Ltd. trade name:
Perhexin 25B] Cross-linking agent 2: N, N-m-phenylene bismaleimide [Ouchi Shinko Co., Ltd. product name: Barnock PM] Cross-linking agent 3: Alkylphenol formaldehyde [Taoka Chemical Co., Ltd. product name: Takkyroll 201] Cross-linking agent 4: Brominated alkylphenol formaldehyde [Taoka Chemical Co., Ltd. product name: Takkyroll 250] Crosslinking agent 5: p-benzoquinone dioxime [Kawaguchi Chemical Co., Ltd. product name: Actor Q] Crosslinking agent 6: tetrachlorobenzoquinone [Kawaguchi Chemical Co., Ltd. product name : Actor CL] Crosslinking agent 7: Zinc dimethacrylate [manufactured by Asada Chemical Co., Ltd.]

(5) Additives Additive 1: Divinylbenzene [Sankyo Kasei] Additive 2: Chlorinated polyethylene [Showa Denko KK product name: Eraslen 301A] Additive 3: 1 Zinhua [Hakusui Chemical Co., Ltd.] Product name: 2 types of zinc white] Additive 4: Stearic acid [Kao Co. product name: Lunack S30] (6) Other polymers (i) Hydrogenated diene copolymer hydrogenated SBR: [JR product Name: Dynaron 1320P] CEBC: [made by JSR Co., Ltd. product name: Dynaron 6200P] SEBS: [made by Shell Chemical Co., Ltd. product name: Krayton
G 1657] SEPS: [Kuraray Co., Ltd. product name: SEPTON 20
07] (ii) Low crystalline α-olefin polymer APAO: [manufactured by Ube Lexen Co., Ltd .: trade name: Ubetac
APAO 2528]

Examples 1 to 25, Comparative Examples 1 to 10 Compositions were prepared according to the following procedures according to the formulations shown in Tables 2 to 6. That is, the polymer, the softening agent, etc. were charged into a pressure type kneader (made by Moriyama Seisakusho Co., Ltd., internal volume: 10 L) in which the temperature inside the tank was set to 180 ° C., melted and mixed, and then discharged. The discharged composition was continuously extruded using a feeder ruder, and strand cut was performed to prepare a master batch pellet. A blend of the obtained masterbatch pellets and a crosslinking agent is continuously and dynamically heat-treated with a twin-screw extruder (Ikegai Co., Ltd., trade name: PCM-45) to obtain a thermoplastic elastomer composition. It was Among the test samples, except for Example 4, pellets of the obtained composition were made into a 2 mm-thick sheet with a 6.5 ounce injection molding machine, and subjected to various tests. For Example 4, pellets of the composition on a 6 inch electrothermal roll (temperature: 180 ° C.)
Was made into a sheet, and a sheet with a thickness of 2 mm was prepared by an electrothermal press and subjected to various tests. Regarding the evaluation of JIS-A hardness and compression set, a 2 mm-thick test piece prepared by the injection molding machine or the press molding machine was used, and after punching, the stack was adjusted to a specified size by stacking and then tested. I served. Further, for the evaluation of tensile strength and maximum elongation, a predetermined test piece was punched out from the sheet with a dumbbell cutter and used for the test. The results are shown in Tables 2-6.

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

[0040] Examples 1-8 is an example using a propylene-based resin of the ethylene copolymer rubber and o olefin-based resin in the range of various present invention, Example 4 was particularly the for profile extrusion It is a thing. Using a propylene resin,
Comparative Examples 1, 3, 8 and 9 using ethylene copolymer rubbers outside the scope of the present invention (Comparative Examples 1 and 3 are designed for injection molding, and Comparative Examples 8 and 9 are designed for profile extrusion, respectively. ), The compositions of the Examples within the scope of the invention are
It can be seen that the compression set and tensile strength are excellent. In Examples 1 and 9 to 11, the ethylene copolymer rubbers within the scope of the present invention were used to adjust various hardnesses. Comparing this with Comparative Examples 1 and 5 to 7 each having an equivalent hardness using an ethylene copolymer rubber outside the scope of the present invention, the thermoplastic elastomer composition within the scope of the present invention Is compression set, tensile strength and molding processability (injection moldability) in comparison with the composition of Comparative Example.
Is excellent. Examples 12-14, 17 and 18 illustrate the same polymer composition as in Example 2 but with various partially cross-linked crosslinking agents within the scope of the present invention. These compositions have thermoplastic elastomer compositions excellent in elastic recovery, mechanical strength and molding processability as in Example 2, although there are some differences in the physical properties based on the crosslinking system. Examples 15,16,19, which has shown the crosslinking system of the completely crosslinked using ethylene-based copolymer rubber within the scope of the present invention, Examples 15 and 16 o olefin
Examples flop propylene-based resin system resin 19 is obtained by using respectively et styrene-based resin as the olefin resin. This is Comparative Example 2, 4, 10 (Comparative Examples 2 and 4 using the outside of the ethylene copolymer rubber scope of the present invention, the flop Ropire <br/> down resin, Comparative Example 10 d styrene-based Compared with (using resin), the thermoplastic elastomer composition within the scope of the present invention has excellent elastic recovery and mechanical strength. Example 2
Nos. 0 to 25 are obtained by dynamically heat-treating the polymer composition of Example 1 to which various polymers and mineral oil softeners were added as other components. It can be seen that these compositions are excellent in elastic recovery, mechanical strength and molding processability as in Example 1. From these comparisons, it is understood that the thermoplastic elastomer composition of the present invention has an excellent balance of elastic recovery, mechanical strength and moldability. Among the compositions of Comparative Examples, EP-6 of the ethylene copolymer rubber has an intrinsic viscosity [η] of less than the lower limit of the range of the present invention. Comparative Example 1 corresponds to Example 1 except that EP-6 was used in place of EP-1 of Example 1 as the ethylene copolymer rubber. Since the intrinsic viscosity [η] is less than the lower limit of the range of the present invention, it is understood that compression set, tensile strength and maximum elongation are poor. EP-7 is a non-oil extended rubber. In Comparative Example 3, Comparative Example 4, and Comparative Example 9, EP-7 was used as the ethylene-based copolymer rubber, and in Comparative Example 3, Example 8 was used.
Comparative Example 4 corresponds to Example 16 and Comparative Example 9 corresponds to Example 4, respectively, but the amount of the mineral oil-based softening agent contained in the thermoplastic elastomer composition is the same. Also, since a non-oil-extended rubber such as EP-7 is used as the ethylene-based copolymer rubber, even if a mineral oil-based softening agent is added in the same amount as that of each example at the time of dynamic crosslinking, any composition It can be seen that the compression set, tensile strength, and maximum elongation of the product are also poor.

[0041]

EFFECTS OF THE INVENTION According to the present invention, a thermoplastic elastomer composition having an excellent balance between elastic recovery and molding processability can be provided by molding with a processing device used for general thermoplastic resins. Is. Therefore, it can be suitably used for interior / exterior parts of automobiles, parts such as packing housings for light electric parts, industrial parts, waterproof sheet parts, gasket seal parts, etc., in which soft vinyl chloride resin or vulcanized rubber is used. I can.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Yamashita 2-11-24 Tsukiji, Chuo-ku, Tokyo JR S Co., Ltd. (72) Inventor Toru Hasegawa 2-11-24 Tsukiji, Chuo-ku, Tokyo JSRL Incorporated company (72) Inventor Kenji Yasuda 2-11-24 Tsukiji, Chuo-ku, Tokyo JR Co., Ltd. (56) References JP-A-1-103639 (JP, A) JP-A-6-1889 (JP , A) JP-A-7-166012 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08

Claims (4)

(57) [Claims] 1. (a) Oil-extended ethylene containing an ethylene copolymer rubber having an intrinsic viscosity [η] of 4.3 to 6.8 dl / g measured at 135 ° C. in a decalin solvent and a mineral oil softener. A polymer composition containing 70% by weight or more of a system-based copolymer rubber and a (b) olefin-based resin with respect to 100% by weight of a total of polymer components is dynamically heat-treated in the presence of a crosslinking agent. A thermoplastic elastomer composition. 2. The thermoplastic according to claim 1, wherein the (a) oil-extended ethylene copolymer rubber contains 100 parts by weight of the ethylene copolymer rubber and 20 to 300 parts by weight of the mineral oil softener. Elastomer composition. 3. A weight ratio of (a) oil-extended ethylene-based copolymer rubber and (b) olefin-based resin ((a) / (b)).
Is 20/80 to 95/5, The thermoplastic elastomer composition according to claim 1 or 2. 4. The (a) oil-extended ethylene copolymer rubber is obtained by desolventizing a mixed solution containing the ethylene copolymer rubber and the mineral oil softener.
The thermoplastic elastomer composition according to any one of 1.