JP2006265319A - Thermoplastic elastomer composition and its molded item - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition that exhibits mechanical properties and extrusion moldability superior to those of conventional thermoplastic elastomers, and a molded item thereof. <P>SOLUTION: The thermoplastic elastomer composition is obtained by compounding 100 pts.wt. of a thermoplastic elastomer component comprising a rubber (A) and a resin (B) with 0.01-2.0 pts.wt. of at least one of a peroxycarbonate and a peroxydicarbonate as a crosslinking agent (C) followed by a dynamic heat treatment. Preferably, the rubber (A) is at least one selected from among ethylene/α-olefin/non-conjugated copolymer rubbers (A1) and ethylene/α-olefin copolymer rubbers (A2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an olefinic thermoplastic elastomer composition and a molded article thereof.

  Conventionally, extrusion vulcanized products made of a rubber compound of ethylene / propylene / non-conjugated diene terpolymer (EPDM) are generally used as automobile parts, electric / electronic parts, and building parts. It has been used in parts that require elasticity.

  On the other hand, instead of vulcanized rubber using ethylene / propylene / non-conjugated diene terpolymer (EPDM) as a sealing material for various applications, from the viewpoint of productivity, environmental friendliness and weight reduction, Thermoplastic elastomers (compositions) that do not require a vulcanization process are beginning to be used.

  As a technology related to the composition of the thermoplastic elastomer, a technology that dynamically crosslinks an ethylene / propylene (non-conjugated diene) copolymer and a crystalline polyolefin is a well-known technology. Polypropylene has been used as the polyolefin.

  In general, however, in conventional thermoplastic elastomers, the addition of a peroxide causes the crystalline polyolefin component to decompose and a molecular weight drop, resulting in sufficient fluidity, but during extrusion molding due to the molecular weight reduction of the crystalline polyolefin component. There was a decrease in elongation at break due to generation of eyes and mechanical properties. In addition, when special molding such as foaming is performed, there is a problem that sufficient melt tension cannot be obtained due to a decrease in molecular weight and the swell during extrusion molding cannot be controlled.

As an improvement, as in JP-A No. 2001-123027 (Patent Document 1), in an extruder that performs dynamic cross-linking, a method is proposed in which resin is side-fed from a barrel in the middle to improve equal extrusion characteristics to the eyes. . However, in such a method, the place where the resin is side-fed and kneading are difficult. Moreover, since resin is added in the middle, there is a concern about deterioration of physical properties such as an increase in hardness.
JP 2001-123027 A

  The present invention seeks to solve the problems associated with the prior art as described above, and provides a thermoplastic elastomer composition and a molding thereof capable of obtaining mechanical properties and extrudability superior to those of conventional thermoplastic elastomers. The purpose is to provide a body.

  The thermoplastic elastomer composition of the present invention is 0.01 parts by weight of at least one of peroxycarbonate and peroxydicarbonate as a crosslinking agent (C) with respect to 100 parts by weight of the component consisting of rubber (A) and resin (B). It is characterized by being obtained by blending ˜2.0 parts by weight and dynamically heat-treating.

  Preferably, the rubber (A) is at least one selected from ethylene / propylene copolymer rubber (A1) and ethylene / propylene / diene copolymer rubber (A2). Preferably, an organic peroxide having a 10-hour half-life temperature of 90 ° C. or higher and a crosslinking agent (C) having a 10-hour half-life temperature not exceeding 90 ° C. are used in combination. Furthermore, it is a thermoplastic elastomer composition using dicetyl peroxy dicarbonate as peroxycarbonate. Moreover, it is a molded body formed by molding the thermoplastic elastomer composition.

  Since the thermoplastic elastomer composition according to the present invention is excellent in extrusion moldability, it can be easily molded into a desired molded product. In addition, it has excellent mechanical properties and is not limited to extrusion molding, and may be injection molded. For molded products, automotive parts, industrial machine parts, electrical and electronic parts, civil engineering and building parts, medical parts, etc. And those that require flexibility, mechanical strength, shape recovery, rebound resilience, high-temperature mechanical properties, and the like.

  Thermoplastic elastomers have physical properties similar to rubber, such as flexibility and impact resilience, and can be processed as thermoplastics as opposed to ordinary rubber. It is made in a large dictionary (Maruzen Co., Ltd., published in 1994).

The thermoplastic elastomer composition according to the present invention will be described.
Examples of the thermoplastic elastomer according to the present invention include olefin-based, styrene-based, vinyl chloride-based, urethane-based, ester-based, amide-based, etc., and include an olefin-based resin, a crosslinked olefin-based rubber, and a softener. It is preferable that it is an olefin-based composition to be contained. Furthermore, the case where rubber (A) and crystalline polyolefin resin (B) are used as components is particularly preferable.

Rubber (A)
The rubber (A) used in the present invention preferably has a glass transition temperature (Tg) of −30 ° C. or lower. Examples of such a rubber component (A) include polybutadiene, poly (styrene-butadiene), Diene rubber such as poly (acrylonitrile-butadiene), saturated rubber obtained by hydrogenation of the diene rubber, isoprene rubber, chloroprene rubber, acrylic rubber such as polybutyl acrylate, and ethylene-propylene copolymer rubber, ethylene-propylene -Crosslinked rubber or non-crosslinked rubber such as diene monomer copolymer rubber and ethylene-octene copolymer rubber, and thermoplastic elastomer containing the rubber component.

  Among the rubbers (A), ethylene / α-olefin (• non-conjugated polyene) copolymer rubber is particularly preferable.

  The ethylene / α-olefin (• non-conjugated polyene) copolymer rubber used in the present invention is a copolymer rubber of ethylene, α-olefin and, if necessary, non-conjugated polyene, for example, ethylene / α-olefin. Examples thereof include olefin / non-conjugated polyene copolymer rubber (A1) and ethylene / α-olefin copolymer rubber (A2).

  The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) used in the present invention is an olefin rubber composed of ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene.

  Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 4-methylpentene-1, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene. 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-methyldecene-1, 11-methyldodecene-1, 12 -Ethyltetradecene-1 and the like. Of these, propylene, 1-butene, 4-methylpentene-1, 1-hexene and 1-octene are preferable. Particularly preferred is propylene.

These α-olefins are used alone or in combination of two or more.
Further, as the non-conjugated polyene, specifically,
1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,4-hexadiene, 7- Linear unconjugated dienes such as methyl-1,6-octadiene, 8-methyl-4-ethylidene-1,7-nonadiene, 4-ethylidene-1,7-undecadiene;
Methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene Cyclic non-conjugated dienes such as 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene, 5-isobutenyl-2-norbornene, cyclopentadiene, norbornadiene;
2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 4-ethylidene-8-methyl-1,7-nanodiene, etc. And triene. Of these, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, cyclopentadiene, and 4-ethylidene-8-methyl-1,7-nanodiene are preferable.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) used in the present invention has a structural unit content (ethylene content) derived from ethylene of 50 mol% or more, usually 50 to 90 mol%, preferably 60 to 85 mol%, and the content of structural units derived from α-olefins having 3 to 20 carbon atoms (α-olefin content) is 50 mol% or less, usually 50 to 10 mol%, preferably 40 to 15 mols %, And the non-conjugated polyene content is usually 0.1 to 30, preferably 0.1 to 25 in terms of iodine value. However, the total of ethylene content and α-olefin content is 100 mol%. The composition of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) is determined by measurement by ¹³ C-NMR.

  The ethylene / α-olefin / non-conjugated polyene copolymer (A1) used in the present invention may be a so-called oil-extended rubber in which a softener, preferably a mineral oil softener, is blended in the production. Examples of the mineral oil softener include conventionally known mineral oil softeners such as paraffin process oil.

The Mooney viscosity [ML _{1 + 4} (100 ° C.)] of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) is usually 10 to 250, preferably 30 to 150.

  The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) as described above can be produced by a conventionally known method.

  The copolymer rubber of ethylene and α-olefin of the present invention and, if necessary, non-conjugated polyene, is ethylene and α having 3 to 20, preferably 3 to 12, more preferably 3 to 8 carbon atoms. -Ethylene / α-olefin copolymer rubber (A2) copolymerized with olefin may also be used.

  Specific examples of such ethylene / α-olefin copolymer (A2) include ethylene / propylene copolymer rubber (EPR), ethylene / 1-butene copolymer rubber (EBR), ethylene / 1- Examples thereof include octene copolymer rubber (EOR).

  The melt flow rate (MFR; ASTM D 1238, 190 ° C., 2.16 kg load) of the ethylene / α-olefin copolymer rubber (A2) is usually 0.1 to 100 g / 10 minutes, preferably 0.2 to 50 g / It is desirable that it is 10 minutes, more preferably 0.5 to 30 g / 10 minutes.

  The α-olefin constituting the ethylene / α-olefin copolymer rubber (A2) is the same as the α-olefin constituting the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1). The copolymer rubber (A2) has a structural unit content (ethylene content) derived from ethylene of 50 mol% or more, usually 50 to 90 mol%, preferably 60 to 85 mol%, and has 3 to 20 carbon atoms. The content of structural units derived from α-olefins (α-olefin content) is 50 mol% or less, usually 50 to 10 mol%, preferably 40 to 15 mol%.

  The copolymer rubber of ethylene and α-olefin and optionally a non-conjugated polyene may consist of only one or more kinds of ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1). It may consist only of a kind or more of ethylene / α-olefin copolymer rubber (A2), and (A1) and (A2) may be used in combination. In that case, the ratio of (A1) to (A2) is not particularly limited. For example, ethylene / α-olefin copolymer rubber (A2) is an ethylene / α-olefin / non-conjugated polyene copolymer rubber. The total amount of (A1) and ethylene / α-olefin copolymer rubber (A2) is 100 parts by weight, and is used in an amount of 50 parts by weight or less, usually 10 to 50 parts by weight.

  The amount of the rubber component as described above is 5 to 95 parts by weight, preferably 10 to 90 parts by weight, more preferably 100 parts by weight of the total amount of the rubber component (A) and the crystalline polyolefin (B). 15 to 85 parts by weight. When this copolymer rubber (A1) and copolymer rubber (A2) are used in the above ratio, a thermoplastic elastomer composition having appropriate softness (hardness) can be obtained.

Resin (B)
The resin (B) used in the present invention is not particularly limited, but is a crystalline polyolefin, particularly a propylene homopolymer, a random copolymer or block copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms. A polymerized propylene copolymer is preferred.

  Specific examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 4-methylpentene-1, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1 -Undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-methyldecene-1, 11-methyldodecene-1, 12-ethyl And tetradecene-1.

  As the comonomer copolymerized with propylene, ethylene and 1-butene are preferable. These α-olefins can be used singly or in combination of two or more.

The constituent unit content (propylene content) derived from propylene in this propylene copolymer is usually 50 to 90% by weight, preferably 55 to 85% by weight, and the constituent unit content (comonomer content) derived from the comonomer is The amount is usually 50 to 10% by weight, preferably 45 to 15% by weight. In addition, the composition of a propylene copolymer is calculated | required by the measurement by < ¹³ > C-NMR.

  The resin (B) used in the present invention can be produced by a known polymerization method. Or a commercially available thing can also be obtained and used.

  The resin (B) has a melt flow rate (MFR; ASTM D 1238, 230 ° C., load 2.16 kg) usually from 0.01 to 100 g / 10 minutes, preferably from 0.1 to 80 g / 10 minutes, more preferably from 0.8. It is desirable that it is 3 to 60 g / 10 minutes.

  The resin (B) is 10 to 90 parts by weight, preferably 15 to 85 parts by weight, and more preferably 20 to 80 parts by weight with respect to 100 parts by weight of the total amount of the rubber component (A) and the resin (B). Used. When the crystalline polyolefin resin (B) is used in a proportion within the above range, a thermoplastic elastomer composition having an appropriate softness (hardness) and sufficient fluidity as a thermoplastic elastomer can be obtained.

Cross-linking agent (C)
The thermoplastic elastomer composition according to the present invention can be prepared by dynamically heat-treating a blend comprising the above components (A) and (B) in the presence of a crosslinking agent (C).

  As the crosslinking agent (C) used in the present invention, it is essential to contain at least one kind of peroxycarbonate and peroxydicarbonate in an amount of 0.01 to 2.0 parts by weight, and other organic peroxides, Sulfur, sulfur compounds, phenolic vulcanizing agents such as phenol resins, and the like may be mixed.

  Specific examples of peroxycarbonate and peroxydicarbonate include bis- (3-methoxybutyl) peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, and bis- (4-tert-butylcyclohexyl) peroxy. Dicarbonate, diisopropylperoxydicarbonate, dicetylperoxydicarbonate, tert-butyl-peroxy-isopropylcarbonate, tert-butyl-peroxy-2-ethylhexylcarbonate, diethyleneglycol-bis- (tert-butyl-peroxycarbonate), Examples include 1,6-bis- (tert-butylperoxycarbonyloxy) hexane. The addition amount at the time of dynamic crosslinking is 0.01 to 2.0 parts by weight. If the amount is less than the minimum, the molecular weight control effect on the crystalline polyolefin resin is low, and if it is more than this, the molecular weight of the crystalline polyolefin resin is low. It becomes higher and the appearance of the molded product deteriorates.

  Specific examples of organic peroxides other than the crosslinking agent (C) include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) Hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3 , 3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert- Examples thereof include butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide and the like.

  Among them, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3 in terms of odor and scorch stability 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane and n-butyl-4,4-bis (tert-butylperoxy) ) Valerate is preferred, with 1,3-bis (tert-butylperoxyisopropyl) benzene being most preferred.

  Furthermore, the crosslinking agent (C) which is at least one of peroxycarbonate and peroxydicarbonate whose 10-hour half-life temperature does not exceed 90 ° C., and organic peroxide whose 10-hour half-life temperature is 90 ° C. or more It is preferable to use a mixture of Examples of at least one of peroxycarbonate and peroxydicarbonate whose 10-hour half-life temperature does not exceed 90 ° C include dicetyl peroxydicarbonate, bis- (4-tert-butylcyclohexyl) peroxydicarbonate, etc. There is. Examples of organic peroxides having a 10-hour half-life temperature of 90 ° C. or higher include dialkyl peroxides such as 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl. -2,5-di (tert-butylperoxy) hexyne-3.

  The other crosslinking agent, for example, the organic peroxide is usually 0.01 to 1.0 part by weight, preferably about 0.03 to 0 parts per 100 parts by weight of the total amount of the rubber (A) and the resin (B). Used at a ratio of 9 parts by weight. When the organic peroxide is used in the above ratio, a thermoplastic elastomer composition in which the rubber (A) is cross-linked is obtained, and rubber properties such as heat resistance, tensile properties, elastic recovery properties, and rebound resilience are sufficient. Can be obtained. Moreover, this composition is excellent in moldability.

  In the present invention, during the crosslinking treatment with the organic peroxide, sulfur, p-quinonedioxime, p, p'-dibenzoylquinonedioxime, N-methyl-N, 4-dinitrosoaniline, nitrobenzene, diphenylguanidine , Crosslinking aids such as trimethylolpropane-N, N'-m-phenylenedimaleimide, or divinylbenzene, triallyl cyanurate, eletin glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate , Polyfunctional methacrylate monomers such as allyl methacrylate, and polyfunctional vinyl monomers such as vinyl butyrate or vinyl stearate can be blended. With such a compound, a uniform and mild crosslinking reaction can be expected. In particular, in the present invention, when divinylbenzene is used, it is easy to handle, has good compatibility with the rubber (A) and resin (B) as the main component of the object to be treated, and has an organic peroxide solubilizing action. In addition, since it functions as a dispersion aid for organic peroxides, it is most preferable because a composition having a uniform cross-linking effect by heat treatment and a balance between fluidity and physical properties can be obtained.

  A softener may be added to the thermoplastic elastomer composition according to the present invention as a fluidity or hardness adjusting agent.

In particular,
Petroleum softeners such as process oil, lubricating oil, paraffin, liquid paraffin, polyethylene wax, polypropylene wax, petroleum asphalt, petrolatum;
Coal tar softeners such as coal tar and coal tar pitch;
Fatty oil softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, coconut oil;
Tall oil;
Sub, (Factis);
Waxes such as beeswax, carnauba wax, lanolin;
Fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, zinc laurate;
Naphthenic acid;
Pine oil, rosin or derivatives thereof;
Synthetic polymer materials such as terpene resin, petroleum resin, coumarone indene resin, atactic polypropylene;
Ester softeners such as dioctyl phthalate, dioctyl adipate, dioctyl sebacate;
Examples thereof include microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, liquid polyisoprene, terminal-modified polyisoprene, hydrogenated terminal-modified polyisoprene, liquid thiocol, and hydrocarbon-based synthetic lubricating oil. Among these, petroleum softeners, particularly process oils are preferably used.
In the present invention, the amount of the softening agent (D) is usually 1 to 60 parts by weight, particularly 5 to 50 parts by weight based on 100 parts by weight of the total amount of the rubber (A) and the resin (B). A range of parts is preferred.

Other components In the thermoplastic elastomer composition according to the present invention, if necessary, additives such as slip agents, fillers, antioxidants, weathering stabilizers, colorants, and the like, in a range not impairing the object of the present invention Can be blended.

Examples of the slip agent include fatty acid amide, silicone oil, glycerin, wax, and paraffinic oil.
Moreover, you may add, after dynamically heat-processing a softener as a fluidity | liquidity and a hardness regulator.

  Examples of the filler include conventionally known fillers, specifically, carbon black, clay, talc, calcium carbonate, kaolin, diatomaceous earth, silica, alumina, graphite, glass fiber and the like.

  The thermoplastic elastomer of the present invention is formed by crosslinking the thermoplastic elastomer. The crosslinking method is not particularly limited, but a method of dynamically heat-treating the crosslinking agent in the presence of the above-described amount is exemplified.

  Here, “dynamically heat-treating” means kneading in a molten state (hereinafter the same).

  The dynamic heat treatment in the present invention is preferably performed in a non-open type apparatus, and is preferably performed in an inert gas atmosphere such as nitrogen or carbon dioxide.

The kneading temperature is usually 50 to 280 ° C, preferably 70 to 240 ° C. The kneading time is usually 1 to 20 minutes, preferably 3 to 10 minutes. Further, the shear force applied is, 10～100,000Sec ^-1 as the shear rate is preferably 100~50,000sec ^-1.

  As a kneading apparatus, a mixing roll, an intensive mixer (for example, a Banbury mixer, a kneader), a single-screw or twin-screw extruder can be used, and a non-open type apparatus is preferable.

  According to the present invention, a thermoplastic elastomer composition in which the rubber component (A) is crosslinked is obtained by the dynamic heat treatment described above.

  The melt flow rate (MFR; ASTM D 1238, 230 ° C., 10 kg load) of the thermoplastic elastomer composition according to the present invention obtained as described above is usually 0.01 to 1000 g / 10 minutes, preferably 0.8. It is 03-500g / 10min, More preferably, it is 0.5-300g / 10min. A thermoplastic elastomer composition having a melt flow rate within the above range is excellent in moldability.

  Although the thermoplastic elastomer according to the present invention can produce a molded body by a known molding technique, it is excellent in controlling the molecular weight of the resin component, so that it can be easily molded into a desired molded product. Molded products are used for automotive parts, industrial machine parts, electrical and electronic parts, civil engineering and building parts, medical parts, etc., and are required to have flexibility, mechanical strength, shape recovery, rebound resilience, high temperature mechanical properties, etc. Things. It is also optimal for foaming applications.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by these Examples.

  In addition, the melt flow rate (MFR) of the thermoplastic elastomer (TPE) compositions obtained in the examples and comparative examples, the hardness and tensile strength of the molded bodies made of the thermoplastic elastomer compositions obtained in the examples and comparative examples. Measurement, evaluation, and evaluation of elongation, compression set, and extrusion moldability were performed according to the following methods.

(1) Melt flow rate (MFR)
The melt flow rate of the thermoplastic elastomer composition was measured at 230 ° C. under a load of 10 kg in accordance with ASTM D1238.
(2) Hardness As for the hardness, Shore A hardness was measured in accordance with JIS K6253.
For the measurement, a sheet was prepared by a press molding machine, and the scale was read immediately after contact with the pressing needle using an A-type measuring device.
(3) Tensile strength and elongation In accordance with JIS K6251, a tensile test was performed under the following conditions, and the tensile strength and elongation at break were measured.
In the test, a sheet was prepared by a press molding machine, and a JIS No. 3 test piece was punched out under the condition of a tensile speed of 500 mm / min.
(4) Compression set A cylindrical molded product having a diameter of 29.0 mm and a thickness of 12.7 mm was produced by a vertical injection molding machine, and compressed to 25% by a spacer in accordance with JIS K6262, at 70 ° C. × 24 Heat treatment was performed for a time, and after the treatment, the sample was left in a constant temperature room at 23 ° C. for 30 minutes, and then the thickness was measured.
(5) Meiyani A belt-shaped die was installed with a 50 mmφ extruder manufactured by Tanabe Plastic Machinery Co., Ltd., and C1 / C2 / C3 / C4 / C5 / H / D = 160/170/180/190/190/190 / The amount per unit extrusion amount of the eye attached to the die at a temperature condition of 190 was measured.

[Example 1]
As the rubber (A), an oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber [ethylene content: 78 mol%, propylene content: 22 mol%, iodine value: 13, Mooney viscosity [ML _{1 + 4} ( 100 ° C.)] 74, (oil extended amount): 40 parts by weight of paraffinic process oil (trade name PW-380, manufactured by Idemitsu Kosan Co., Ltd.) with respect to 100 parts by weight of rubber; ] 70 parts by weight and 30 parts by weight of a propylene / ethylene copolymer (MFR = 10 g / 10 minutes (230 ° C., 2.16 kgf)) as a resin (B), carbon black masterbatch (carbon black 40% by weight, low density polyethylene) 60% by weight) 2.5 parts by weight,
0.1 part by weight of a phenolic antioxidant [Nippon Ciba Geigy Co., Ltd., trade name: Irganox 1010] as an antioxidant,
Diazo weathering stabilizer [manufactured by Ciba Geigy Japan Ltd., trade name: Tinuvin 326] as a weathering agent and 0.1 part by weight of HALS weathering stabilizer [Sankyo Co., Ltd., trade name: Sanol LS-770] 0.05 weight Part,
Fatty acid amide based lubricant as a lubricant [made by Lion Co., Ltd., trade name Armoslip CP] 0.3 part by weight Dicetyl peroxydicarbonate as a peroxycarbonate as a crosslinking agent (C) [made by Kayaku Akzo Co., Ltd., a product Name Parkadox 24] 0.5 part by weight, organic peroxide [manufactured by NOF Corporation, trade name Perhexin 25B] 0.32 part by weight, and divinylbenzene (DVB) 0.24 part by weight as a crosslinking aid Are sufficiently mixed with a Henschel mixer, and an extruder [product number TEM-50, manufactured by Toshiba Machine Co., Ltd., L / D = 40, cylinder temperature: C1 to C2 120 ° C, C3 to C4 140 ° C, C5 to C6 160 ° C, C7-C8 200 ° C., C9-C 12 220 ° C., die temperature: 210 ° C., screw rotation speed: 200 rpm, extrusion rate: 40 kg / h] Granulation was carried out while injecting 20 parts by weight of process oil [manufactured by Idemitsu Kosan Co., Ltd., trade name: PW-100] into a cylinder to obtain pellets of a thermoplastic elastomer composition. The resulting thermoplastic elastomer composition had an MFR of 30 g / 10 min (230 ° C., 10 kg load).

  The molded body obtained from this pellet-shaped thermoplastic elastomer composition and its extrusion moldability were evaluated according to the above-mentioned method. The hardness was JIS-A80, the tensile strength was 8.4 MPa, the elongation at break was 620%, and the compression set was 43%. The eyes generated at that time were 10 g / T-ML.

[Comparative Example 1]
In Example 1, it carried out like Example 1 except not having used peroxycarbonate as a crosslinking agent. The resulting thermoplastic elastomer composition had an MFR of 110 g / 10 min (230 ° C., 10 kg load). Further, the molded body obtained from the pellet-shaped thermoplastic elastomer composition and its extrusion moldability were evaluated according to the above method. The hardness was JIS-A81, the tensile strength was 7.3 MPa, the elongation at break was 520%, and the compression set was 44%. The eyes generated at that time were 45 g / T-ML.

Claims (7)

  To 100 parts by weight of the rubber (A) and the resin (B), 0.01 to 2.0 parts by weight of at least one of peroxycarbonate and peroxydicarbonate as a cross-linking agent (C) is blended. A thermoplastic elastomer composition obtained by heat treatment.   The rubber (A) is at least one selected from ethylene / α-olefin / non-conjugated polyene copolymer rubber (A1) and ethylene / α-olefin copolymer rubber (A2). The thermoplastic elastomer composition according to claim 1.  The thermoplastic elastomer composition according to any one of claims 1 to 2, wherein the crosslinking agent (C) is dicetyl peroxy dicarbonate.   The thermoplastic elastomer composition according to any one of claims 1 to 3, further comprising 0.01 to 1.0 part by weight of a crosslinking agent other than the crosslinking agent (C).   The thermoplastic elastomer composition according to claim 4, wherein the crosslinking agent other than the crosslinking agent (C) is an organic peroxide.   6. The organic peroxide having a 10-hour half-life temperature of 90 ° C. or higher and a crosslinking agent (C) having a 10-hour half-life temperature not exceeding 90 ° C. are used in combination. The thermoplastic elastomer composition described in 1.  The molded object formed by shape | molding the thermoplastic elastomer composition in any one of Claims 1-6.