JP2015205944A - Thermoplastic elastomer - Google Patents

Abstract

The present invention provides a thermoplastic elastomer having excellent moldability, heat resistance and oil resistance in addition to excellent thermal conductivity and flexibility. A raw material composition containing (A) an olefin copolymer rubber, (B) a polyolefin resin, (C) a thermally conductive filler, a magnesium compound filler, and (D) a crosslinking agent. It is a thermoplastic elastomer that has been subjected to dynamic crosslinking by heat treatment, the component (C) is a magnesium compound, the component (A) is 60 to 90 parts by mass, the component (B) is 10 to 40 parts by mass, C) to 100 to 450 parts by mass with respect to a total of 100 parts by mass of component (A) + (B), and component (D) to 0.05 to to 100 parts by mass with respect to a total of 100 parts by mass of component (A) + (B). 5 parts by mass is contained. [Selection figure] None

Description

  The present invention relates to a thermoplastic elastomer. More specifically, the present invention relates to a thermoplastic elastomer suitable as a heat radiating member for electronic parts, automobiles or machines.

  In an electronic component or the like, a heat radiating member made of a heat conductive material is interposed between the heat generating part and the heat radiating part in order to efficiently transmit the heat of the heat generating part to the heat radiating part and prevent the heat generating part from overheating. As the heat radiating member, a material having rubber elasticity is used, and a soft material that is easily adhered to the heat generating portion and the heat radiating portion is preferably used. As such a material, there is one in which thermal conductivity is imparted by blending a thermoplastic elastomer with a thermal conductive filler, which is disclosed in Patent Document 1, for example. The thermoplastic elastomer of Patent Document 1 contains a hydrogenated diene copolymer, a liquid component, and a thermally conductive filler. The liquid component is selected from a softener, a plasticizer, and a liquid polymer, and a thermoplastic elastomer having excellent flexibility can be obtained by these actions. Examples of the thermally conductive filler include carbon-based materials, metal-based materials, ceramic-based materials, silica-based materials, and composite materials thereof. Any material can be used as long as it can provide thermal conductivity. it can.

  By the way, not only for heat dissipation applications, but looking at various thermoplastic elastomers, olefin-based thermoplastic elastomers are extremely excellent in molding processability, for example, various molding methods such as injection molding, extrusion molding, blow molding and the like. Can be processed. For this reason, applications such as seals around automobile doors and windows are expanding. As this type of thermoplastic elastomer, for example, in Patent Document 2, a polyolefin resin, an ethylene copolymer rubber, an organic peroxide as a crosslinking agent, and a specific crosslinking aid are dynamically crosslinked by heat treatment. The resulting thermoplastic elastomer is disclosed. In this thermoplastic elastomer, the polyolefin resin is 5 to 95 parts by weight, preferably 7 to 70 parts by weight, more preferably 10 to 50 parts by weight, out of a total amount of 100 parts by weight of the polyolefin resin and the ethylene copolymer rubber. . The organic peroxide is mixed in an amount of 0.001 to 5 parts by weight, and the crosslinking assistant is mixed in an amount of 0.01 to 5 parts by weight with respect to 100 parts by weight of the total amount of polyolefin resin and ethylene copolymer rubber. Has been.

JP2011-236365A JP 2003-73503 A

  The thermoplastic elastomer of Patent Document 1 is highly flexible because it contains a large amount of the liquid component (B), but since the hydrogenated diene copolymer (A) is used, the melting point of the elastomer itself. Becomes lower. Therefore, there is a limit to heat resistance, and reliability is lacking in heat dissipation measures for electronic components that tend to increase the amount of heat generation year by year.

  On the other hand, the olefinic thermoplastic elastomer of Patent Document 2 has no thermal conductivity and cannot be used as a heat radiating member as it is, but has good heat resistance. However, since it contains ethylene copolymer rubber, it is inherently poor in oil resistance, and simply adding thermal conductivity to this thermoplastic elastomer limits the applications that can be used as a heat radiating member and requires oil resistance. Applications cannot be extended to heat generating parts inside automobiles and machines.

  Accordingly, an object of the present invention is to provide a thermoplastic elastomer having not only excellent thermal conductivity and flexibility but also good moldability, heat resistance and oil resistance.

  In the present invention, a raw material composition containing (A) an olefin copolymer rubber, (B) a polyolefin resin, (C) a thermally conductive filler, and (D) a crosslinking agent is dynamically treated by heat treatment. A crosslinked thermoplastic elastomer, wherein the component (C) is a magnesium compound, the component (A) is 60 to 90 parts by mass, the component (B) is 10 to 40 parts by mass, and the component (C). 100 to 450 parts by mass with respect to a total of 100 parts by mass of the component (A) + (B), and the component (D) with respect to a total of 100 parts by mass of the component (A) + (B). It is a thermoplastic elastomer characterized by containing ˜5 parts by mass.

  This thermoplastic elastomer further contains (E) a plasticizer and (F) an anti-aging agent, and the component (E) is added in an amount of 1 part per 100 parts by mass in total of the components (A) + (B). It is preferable to contain 0.05-1 mass part of said component (F) with respect to a total of 100 mass parts of said component (A) + (B).

  The component (A) olefin copolymer rubber is preferably at least one selected from the group consisting of an ethylene-α-olefin-diene copolymer, an isobutylene-isoprene copolymer, or an acrylonitrile-diene copolymer. Become.

  The component (B) polyolefin-based resin is preferably made of at least one selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer.

  In the present invention, “OO to XX” indicating a numerical value range includes a lower limit numerical value (OO) and an upper limit numerical value (XX). That is, if it is accurately described, it will be “XX or more and XX or less”.

  According to the thermoplastic elastomer of the present invention, a raw material composition containing (A) an olefin copolymer rubber, (B) a polyolefin resin, and (D) a crosslinking agent is dynamically crosslinked by heat treatment. Therefore, it has good moldability and heat resistance. And by specifying the balance of the content of (A) the olefin copolymer rubber and (B) the polyolefin resin, (D) the content of the cross-linking agent is suppressed, and excellent flexibility is obtained. Moreover, it has favorable thermal conductivity by containing a specific amount of the (C) magnesium compound. In addition, the magnesium compound is difficult to absorb oil, and by containing this, the proportion of the (A) olefin copolymer rubber in the thermoplastic elastomer is kept relatively small, so that it has good oil resistance. Have both.

  Furthermore, when (E) a plasticizer and (F) an anti-aging agent are contained, flexibility and heat resistance can be improved, and oil resistance can also be improved.

  The thermoplastic elastomer of the present invention contains (A) an olefin copolymer rubber, (B) a polyolefin resin, (C) a magnesium compound that is a thermally conductive filler, and (D) a crosslinking agent. Preferably, (E) a plasticizer and (F) an anti-aging agent are further contained.

<(A) Olefin copolymer rubber>
(A) As the olefin copolymer rubber, ethylene-α-olefin-diene copolymer (EPDM), acrylonitrile-diene copolymer (NBR) or isobutylene-isoprene copolymer (IIR) can be used. . Among these, EPDM is preferable from the viewpoints of mechanical strength and availability. (A) The olefin copolymer rubber can be used alone or in combination of two or more.

<(B) Polyolefin resin>
(B) As polyolefin resin, polyethylene, a polypropylene, and an ethylene-propylene copolymer can be used. The copolymer may be homo, random, or block. (B) Polyolefin resin can be used 1 type or in combination of 2 or more types.

  The balance of the content of the (A) olefin copolymer rubber and the (B) polyolefin resin is such that (B) the polyolefin resin is 10 to 40 with respect to 60 to 90 parts by mass of the (A) olefin copolymer rubber. Mass parts. If this range is exceeded and the (A) olefin copolymer becomes excessive, the oil resistance is poor. Conversely, if the (B) polyolefin-based resin is excessive, flexibility is lacking.

<(C) Thermally conductive filler>
(C) A thermally conductive filler imparts thermal conductivity to a thermoplastic elastomer. (C) A magnesium compound is used as the thermally conductive filler. (C) The magnesium compound used as the heat conductive filler is specifically a magnesium oxide such as magnesium oxide, magnesium carbonate, or magnesium hydroxide. Magnesium oxide can be used alone or in combination of two or more. Since these magnesium compounds hardly absorb oil, they contribute to improvement of oil resistance. That is, when the magnesium compound is contained in the thermoplastic elastomer, the proportion of the (A) olefin copolymer rubber in the thermoplastic elastomer can be suppressed relatively small, and the oil resistance can be improved.

  The shape of the filler is not particularly limited, and may be a spherical shape, a needle shape, a fiber shape, a scale shape, a dendron, a flat plate, an indefinite shape, or the like. Moreover, the average particle diameter of a filler should just be about 0.1-500 micrometers. If the average particle size of the filler is too small, the viscosity of the thermoplastic elastomer may increase and molding processability may decrease. On the other hand, if the average particle size of the filler is too large, the appearance of the molded product may be deteriorated.

  Content of a magnesium compound shall be 100-450 mass parts with respect to a total of 100 mass parts of (A) olefin-type copolymer rubber + (B) polyolefin-type resin. If it is less than 100 parts by mass, the thermal conductivity is insufficient and the function as a heat radiating member is lowered. On the other hand, when it exceeds 450 parts by mass, the content of the (A) olefin copolymer rubber is relatively decreased, and the flexibility is lowered.

<(D) Crosslinking agent>
(D) A crosslinking agent is added in order to bridge | crosslink (A) olefin type copolymer rubber. Examples of the crosslinking agent include organic peroxides and resin crosslinking agents.

  Examples of the organic peroxide include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, and peroxyesters. Among these, peroxyketals, dialkyl peroxides, and diacyl peroxides are preferable from the viewpoint of safety and ease of handling.

  Examples of ketone peroxides include methyl ethyl ketone peroxide, cyclohexanone peroxide, and acetylacetone peroxide.

  Examples of peroxyketals include 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, and the like. .

  Examples of the hydroperoxide include 4-mentane hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, and the like.

  Examples of dialkyl peroxides include di-tert-butyl peroxide, tert-butyl cumyl peroxide, and dicumyl peroxide.

  Diacyl peroxides include diisobutyryl peroxide, dilauroyl peroxide, dibenzoyl peroxide, and the like.

  Examples of peroxydicarbonates include diisopropyl peroxydicarbonate and dibutyl peroxydicarbonate.

  Peroxyesters include 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3,2, 4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) Valerate, tert-butyl peroxycumene and the like can be mentioned.

  Examples of the resin crosslinking agent include phenol-aldehyde resin, melamine resin, and epoxy resin.

  Examples of the phenol-aldehyde resin include p-substituted phenol compounds, o-substituted phenol-aldehyde condensates, m-substituted phenol-aldehyde condensates, and brominated alkylphenol-aldehyde condensates.

  Examples of the melamine resin include methylated melamine resin, butylated melamine resin, butylated urea melamine resin, and isobutyl alcohol-modified melamine resin.

  Examples of the epoxy resin include brominated epoxy resin, bisphenol A condensed epoxy resin, bisphenol F condensed epoxy resin, and biphenyl type epoxy resin.

  (D) Content of a crosslinking agent shall be 0.05-5 mass parts with respect to a total of 100 mass parts of (A) olefin copolymer rubber + (B) polyolefin resin. When the amount is less than 0.05 parts by mass, crosslinking is insufficient and mechanical properties are deteriorated. On the other hand, when the amount is more than 5 parts by mass, the cross-linking proceeds more than necessary, which is not preferable because the moldability is lowered from the viewpoint of flexibility.

<(E) Plasticizer>
(E) When a plasticizer is added, flexibility can be improved. In addition, when a plasticizer is added to the elastomer, the absorbed weight of the oil is reduced accordingly, so that the oil resistance can be improved. (E) As the plasticizer, phthalate ester, phosphate ester, trimellitic ester, adipate, and the like can be used.

  Examples of the phthalate ester plasticizer include dimethyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, and diisononyl phthalate.

  Examples of the phosphoric ester plasticizer include tributyl phosphate and triphenyl phosphate.

  Examples of trimellitic acid ester plasticizers include trimethyl trimellitic acid, triethyl trimellitic acid, trioctyl trimellitic acid, and tri-2-ethylhexyl trimellitic acid.

  Examples of adipate plasticizers include di-2-ethylhexyl adipate, diisodecyl adipate, and dibutyl diglycol adipate.

  (E) Content of a crosslinking agent shall be 1-30 mass parts with respect to a total of 100 mass parts of (A) olefin copolymer rubber + (B) polyolefin resin. If it is less than 1 part by mass, it may not be preferable from the viewpoint of flexibility. On the other hand, if the amount is more than 30 parts by mass, the material may not be filled with the plasticizer and may bleed out, which is not preferable.

<(F) Anti-aging agent>
(F) When an anti-aging agent is added, heat aging resistance can be improved. As an anti-aging agent, an anti-aging agent such as phenol, phosphorus, sulfur or amine can be used.

  Examples of the phenol-based anti-aging agent include a monophenol-based anti-aging agent, a bisphenol-based anti-aging agent and a polymer type phenol-based anti-aging agent. Examples of monophenol antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2-tert-butyl-4-methoxyphenol, Examples include 3-tert-butyl-4-methoxyphenol and n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate. Examples of the bisphenol antioxidant include 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-thiobis. (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3- tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5.5] undecane and the like. As the polymer type phenolic antioxidant, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6- Tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis- (4′-hydroxy-3′-tert-butylphenyl) butyric acid] glycol ester, 1,3,5-tris (3 ′, 5′-di-t-butyl-4 '-Hydroxybenzyl) -sec-triazine-2,4,6- (1H, 3H, 5H) trione, pentaerythritol tetrakis [1- (3,5-di-tert-butyl-4-hydro Shifeniru) propionate], and a D-alpha-tocopherol and the like.

  Phosphorous antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenylditridecyl) phosphite, octadecyl Phosphite, tris (nonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl -4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris (2 , 4-Di-tert-Buchi Phenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol-di-phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite 2,2′-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite and the like.

  Examples of sulfur-based antioxidants include dilauryl 3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3′-thiodipropionate, pentaerythritol tetrakis (3-laurylthio). Propionate), 2-mercaptobenzimidazole and the like.

  Amine-based antioxidants include phenyl-1-naphthylamine, 4,4-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamido) diphenylamine, N, N′-di-2-naphthyl. -p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N '-(1,3-dimethylbutyl) -p- Examples include phenylenediamine, N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, and the like.

  (F) Content of anti-aging agent shall be 0.05-1 mass part with respect to a total of 100 mass parts of (A) olefin copolymer rubber + (B) polyolefin resin. When it is less than 0.05 parts by mass, the heat aging resistance is lowered. On the other hand, when it is more than 1 part by mass, it is not preferable from the viewpoint of mechanical strength and flexibility.

<Other additives>
In addition to the components (A) to (F), various additives can be added to the thermoplastic elastomer as long as the effects of the present invention are not impaired. Specifically, UV stabilizers such as hindered amines, processing aids such as stearic acid, pigments such as titanium dioxide, reinforcing agents or fillers such as carbon black, white carbon, clay and talc, aluminum hydroxide, hydroxylation Examples include magnesium, halogen-based and phosphorus-based flame retardants, crosslinking aids, lubricants, and the like.

  In addition, (C) the heat conductive filler can contain sufficient magnesium conductivity by containing only the magnesium compound, but if the amount is small enough not to reduce the oil resistance, the magnesium of component (C) In addition to the compound, a combination of other thermally conductive fillers such as boron nitride, zinc oxide, carbon fiber, and graphite is also allowed. As the thermally conductive filler that can be used in combination with the magnesium compound of component (C), a new Mohs hardness of 1 to 8 is preferred. Beyond that, the kneader is worn, which is not preferable. Therefore, alumina and aluminum nitride are not preferable.

<Method for producing thermoplastic elastomer>
The thermoplastic elastomer is basically produced by dynamically cross-linking (A) an olefin copolymer rubber with (D) a cross-linking agent in the thermoplastic elastomer composition containing the above components. In a desirable production method, first, prior to dynamic crosslinking, (D) components other than the crosslinking agent are kneaded while heating and mixed uniformly. Next, (D) a crosslinking agent is added, and (A) the olefin copolymer rubber is dynamically crosslinked. In the dynamic crosslinking, a shearing force is applied by kneading while heat-treating, and (A) the olefin copolymer rubber is crosslinked. By kneading, (A) the olefin copolymer rubber is crosslinked, and (B) is finely dispersed in the matrix phase of the polyolefin resin to obtain a thermoplastic elastomer. The heating temperature at the time of mixing and dynamic crosslinking is higher than the melting point of (B) polyolefin resin and lower than the decomposition start temperature of (A) olefin copolymer rubber, specifically 130 to 210 ° C., preferably It is 170-200 degreeC, More preferably, it is 185-195 degreeC. As an apparatus for performing mixing and dynamic crosslinking, a Banbury mixer, a Brabender mixer, a pressure kneader, a single screw extruder, a twin screw extruder, a roll, or the like can be used.

  The obtained thermoplastic elastomer has (A) an olefin copolymer rubber cross-linked and forms the above phase structure, so that it exhibits elasticity like rubber at room temperature. Have. Therefore, it can be molded into a predetermined shape by a known thermoplastic resin molding method such as an extrusion molding method, an injection molding method, a blow molding method, or a compression molding method. Moreover, this thermoplastic elastomer has (C) the heat conductive filler uniformly disperse | distributed, and is provided with heat conductivity.

<Preparation of thermoplastic elastomer>
First, using the following raw materials, the thermoplastic elastomers of Examples 1 to 15 and Comparative Examples 1 to 8 were prepared with the formulations shown in Tables 1 to 3.

(A) Olefin copolymer rubber Ethylene-propylene-diene copolymer rubber (EPDM) (Susplen Chemical Esplene EPDM)
Acrylonitrile-butadiene rubber (NBR) (JSRN241 manufactured by JSR Corporation)
Isobutylene-isoprene rubber (IIR) (JSRBUTYL065 manufactured by JSR Corporation)

(B) Polyolefin-based resin, propylene homopolymer (PM600A manufactured by Sun Allomer Co., Ltd.)
Ethylene-propylene random polymer (PM731 manufactured by Sun Allomer Co., Ltd.)
Ethylene-propylene block polymer (PM854X manufactured by Sun Allomer Co., Ltd.)

(C) Thermally conductive filler Magnesium oxide (spherical, average particle size 20 μm)
Magnesium carbonate (spherical, average particle size 5μm)
Aluminum nitride (spherical, average particle size 1μm)
Alumina (spherical, average particle size 45μm)
Boron nitride (scale-like, average particle size 15μm)
Carbon fiber (7μm diameter, fiber length 50μm)

(D) Crosslinking agent 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (Perhexa 25B manufactured by NOF Corporation)
Brominated alkylphenol formaldehyde resin (Tactrol 250-1 manufactured by Taoka Chemical Co., Ltd.)

(E) Plasticizer diisononyl phthalate (DINP manufactured by J-Plus Co., Ltd.)
Dibutyl diglycol adipate (ADEKA Sizer RS-107 manufactured by ADEKA)

(F) Anti-aging agent Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010 manufactured by Ciba Specialty Chemicals)

  In the preparation of the thermoplastic elastomer, (D) all raw materials except for the crosslinking agent are charged into a pressure kneader (manufactured by Moriyama Co., Ltd.) heated to 190 ° C., melted and kneaded at 32 rpm, and kneaded until all the materials are melted. (Kneading time 15 minutes). Thereafter, (D) a crosslinking agent was added to obtain a raw material composition. This raw material composition was further kneaded with a pressure kneader heated to 190 ° C., thereby performing dynamic crosslinking to obtain a thermoplastic elastomer (kneading time 5 minutes). The obtained thermoplastic elastomer was supplied to a kneader ruder (manufactured by Kasamatsu Chemical Research Laboratory) and granulated.

<Preparation of test sample>
Next, each of the granulated thermoplastic elastomers was supplied to an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., ES600) heated to 230 ° C. to prepare a 30 mm × 150 mm × 2 mm plate.

  Various physical properties of the obtained plates of Examples and Comparative Examples were measured and evaluated. The results are also shown in Tables 1 to 3 above. The measurement method and evaluation method of each physical property are as follows.

(Oil resistance)
It was immersed in a designated oil (IRM903oil) at 120 ° C. for 72 hours, and the ratio of the weight change after immersion to the weight before immersion was calculated as the weight change rate.

(Thermal characteristics)
The specific heat was measured according to JIS K 7123, the specific gravity was measured according to JIS K 7112, the thermal diffusivity was measured according to JIS R 1611, and the thermal conductivity (W / m · K) was determined (thermal conductivity = Specific heat x specific gravity x thermal diffusivity).

(Flexibility)
In accordance with JIS K 6253, the hardness (ShA) was measured with a type A dilometer tester.

(Tensile properties)
According to JIS K 6251, tensile strength (MPa) and elongation (%) were measured at a test speed of 500 mm / min.

(Heat-resistant)
In accordance with JIS K 6257, the test piece (No. 3 dumbbell) was allowed to stand in a high-temperature bath at 160 ° C. for 500 hours, and then the elongation (%) was measured at a test speed of 500 mm / min in accordance with JIS K 6251 before the heat resistance test. The retention after the heat test was determined from the elongation (%) of the film and the elongation (%) after the heat test.

(Manufacturability)
Whether the kneader ruder and the injection molding machine were worn during the adjustment of the thermoplastic elastomer and the plate production was visually confirmed.
○: No wear ×: Wear
(Formability evaluation)
The appearance after injection molding was confirmed visually.
○: Good ×: Bad

  From the results in Table 1, the thermoplastic elastomer contains (A) 60 to 90 parts by mass of olefin copolymer rubber and (B) 10 to 40 parts by mass of polyolefin resin, and (A) + (B If the composition contains 100 to 450 parts by mass of (C) a magnesium compound that is a thermally conductive filler and (D) 0.05 to 5 parts by mass of a crosslinking agent, for a total of 100 parts by mass of It is recognized that in addition to excellent thermal conductivity and flexibility, it also has good moldability, heat resistance and oil resistance.

  Moreover, from the result of Table 2, 1-30 mass parts of (E) plasticizer and (F) anti-aging agent are further 0.05-100 with respect to a total of 100 mass parts of component (A) + (B). It became clear that inclusion of 1 part by mass not only improved flexibility and heat resistance, but also improved oil resistance.

  On the other hand, referring to Table 3, from the results of Comparative Example 1, when (A) olefin copolymer rubber is excessively contained in (B) polyolefin resin, the oil resistance is inferior and tensile It can be seen that the strength is insufficient. On the contrary, when (B) polyolefin resin is excessively contained with respect to the content of (A) olefin copolymer rubber, the molding processability is inferior and the hardness exceeds 90, so that it is flexible. Since it is scarce, it turns out that it cannot contact | adhere to a heat generating body as a heat radiating member from the comparative example 2.

In addition, from the results of Comparative Examples 3 and 4, when the same thermal conductivity was added by adding aluminum nitride or alumina instead of (C) the magnesium compound as the thermal conductive filler, the kneader was worn. However, it was confirmed that the productivity was lacking. From the results of Comparative Examples 5 and 6, it was revealed that good oil resistance could not be obtained when it was attempted to add the same thermal conductivity using only boron nitride or carbon fiber instead of the magnesium compound. Here, from the comparison with Examples 9 and 10 shown in Table 1, when other heat conductive fillers are used in combination with the magnesium compound, the oil resistance is improved if it is about 5% by mass or less based on the magnesium compound. It was found that the inclusion was acceptable. Moreover, from the result of Comparative Example 7, even when only the magnesium compound is used as the (C) heat conductive filler, if the content is excessive, the manufacturability and molding processability are lacking and the tensile elongation is inferior. I understand that.

Claims (4)

A raw material composition containing (A) an olefin copolymer rubber, (B) a polyolefin resin, (C) a thermally conductive filler, and (D) a crosslinking agent was subjected to dynamic crosslinking by heat treatment. A thermoplastic elastomer,
The component (C) is a magnesium compound,
60 to 90 parts by mass of the component (A),
10 to 40 parts by mass of the component (B),
100 to 450 parts by mass of the component (C) with respect to a total of 100 parts by mass of the component (A) + (B),
0.05 to 5 parts by mass of the component (D) with respect to a total of 100 parts by mass of the component (A) + (B),
A thermoplastic elastomer containing the thermoplastic elastomer. (E) a plasticizer, and (F) an anti-aging agent,
1 to 30 parts by mass of the component (E) with respect to a total of 100 parts by mass of the component (A) + (B),
0.05 to 1 part by mass of the component (F) with respect to a total of 100 parts by mass of the component (A) + (B),
The thermoplastic elastomer according to claim 1, which is contained.   The component (A) olefin copolymer rubber is composed of at least one selected from the group consisting of an ethylene-α-olefin-diene copolymer, an isobutylene-isoprene copolymer, or an acrylonitrile-diene copolymer. The thermoplastic elastomer according to claim 1 or 2, characterized in that   The said component (B) polyolefin-type resin consists of at least 1 sort (s) chosen from the group which consists of polyethylene, a polypropylene, and an ethylene-propylene copolymer, In any one of Claims 1-3 characterized by the above-mentioned. The thermoplastic elastomer described.