JP2011236365A - Thermoplastic elastomer composition and heat-conductive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition capable of manufacturing a molded article being excellent in flexibility, heat resistance, cold-resistance, thermal conductivity, close adhesion property, rework property and recycle property and not generating a siloxane vapor.SOLUTION: The thermoplastic elastomer composition contains 100 pts.mass of a hydrogenated diene-based copolymer (A) in which a block copolymer of a polymer block having a vinyl bonding content of less than 25% and a polymer block having a vinyl bonding content of 40% or more is hydrogenated, a hydrogenation ratio of a double bond originated in a conjugated diene is 80% or more and a weight average molecular weight is 50,000-700,000; 5-1,000 pts.mass of at least one liquid-like component (B) selected from the group consisting of a softener, a plasticizer, a lubricant and a liquid-like polymer; and heat-conductive filler (C).

Description

  The present invention relates to a thermoplastic elastomer composition and a heat conductive sheet. More specifically, the present invention relates to a thermoplastic elastomer composition used for a molded product used for improving thermal conductivity between a heat generating portion and a heat radiating portion of an electronic device, and a heat conductive sheet using the same.

  In recent years, the amount of heat generated from the heat generating portion has increased with the reduction in size and performance of electronic devices. For this reason, issues such as product performance degradation, product life shortening, and safety degradation (burns, fires) have become obvious, and heat dissipation measures to dissipate the heat generated through heat dissipation parts such as heat sinks and product housings to the outside Is important. Generally, heat generating portions such as CPUs and LED boards and heat radiating portions such as heat sinks and product housings are made of a material with poor flexibility such as metal, ceramic and resin. Therefore, it is known to use a heat conductive sheet between the heat generating part and the heat radiating part in order to increase the adhesion between the heat generating part and the heat radiating part and efficiently conduct heat.

  As the heat conductive sheet, in order to enhance the heat conductivity, a heat conductive sheet in which a heat conductive filler such as aluminum oxide, boron nitride, aluminum nitride, zinc oxide, silicon carbide, quartz, aluminum hydroxide is added to silicone is used. Is disclosed (for example, see Patent Documents 1 to 3). However, when the low molecular weight siloxane vapor scattered from the silicone is decomposed by heat due to electric current on the surface of a relay contact or the like, there is a problem that insulating silica is deposited and a contact failure occurs.

  In order to prevent generation of low molecular weight siloxane vapor from the heat conductive sheet, a polymer other than silicone has been proposed as a base polymer for the heat conductive sheet. For example, a heat conductive sheet in which a heat conductive filler such as aluminum oxide, aluminum nitride, titanium dioxide, copper, aluminum, boron nitride, silicon nitride, silicon carbide, metal powder, and titanium boride is added to acrylic polymer is disclosed. (For example, see Patent Documents 4 to 5).

  Zinc oxide, silicon nitride, aluminum nitride, silicon carbide having needle-like crystal parts as paraffinic oil and filler as a hydrogenated block copolymer consisting of conjugated diene and aromatic vinyl and having a specific structure Also disclosed is a thermally conductive sheet to which boron nitride or the like is added (for example, see Patent Document 6).

Japanese Patent No. 3183502 Japanese Patent No. 2728607 Japanese Patent Application Laid-Open No. 2000-233452 Japanese Patent No. 3636884 Japanese Patent No. 4086322 JP 2007-277300 A

  The heat conductive sheet using an acrylic polymer as a base polymer has a problem that the recyclability is inferior because it has a cross-linked structure due to a chemical bond like silicone. In addition, the heat conductive sheet made of a conjugated diene and aromatic vinyl and using a hydrogenated block copolymer with a specific structure as the base polymer has improved flexibility due to its low paraffinic oil content. There is room for.

  Moreover, since use of a heat conductive sheet is desired according to various environments, it is also required to be excellent in cold resistance. Furthermore, in consideration of actual use, it is preferable that the reworkability is excellent.

  The present invention has been made in view of such problems of the prior art, and the subjects are flexibility, heat resistance, cold resistance, thermal conductivity, adhesion, reworkability, and recyclability. Another object of the present invention is to provide a thermoplastic elastomer composition that is excellent in manufacturing and can produce a molded article that does not generate siloxane vapor even when heated under predetermined conditions.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have achieved the above-mentioned problems by using a hydrogenated block copolymer having a polyethylene-polyethylene-butylene-polyethylene-like structure as the base polymer. As a result, the present invention has been completed.

  That is, according to the present invention, the following thermoplastic elastomer composition and thermally conductive sheet are provided.

[1] (A) At least one selected from the group consisting of a hydrogenated diene copolymer that satisfies the following conditions (A1) and (A2), and (B) a softener, a plasticizer, and a liquid polymer A liquid component and (C) a thermally conductive filler, and (B) the liquid component is 5-1000 parts by mass with respect to 100 parts by mass of the (A) hydrogenated diene copolymer, The (A) hydrogenated diene copolymer includes a polymer block (i) including a structural unit derived from the first conjugated diene compound, and a polymer block including a structural unit derived from the second conjugated diene compound. (Ii) and a structure represented by (i)-(ii)-(i) (wherein (i) represents a polymer block (i), and (ii) represents a polymer block) A block copolymer having (ii)) is hydrogenated to form the polymer block (I) is a polymer block having a vinyl bond content of less than 25%, the polymer block (ii) is a polymer block having a vinyl bond content of 40% or more, and the block copolymer is The content of the polymer block (i) is 5 to 90% by mass with respect to the total of the polymer block (i) and the polymer block (ii), and the content of the polymer block (ii) A thermoplastic elastomer composition having a ratio of 10 to 95% by mass.
(A1) The hydrogenation rate of double bonds derived from conjugated dienes is 80% or more.
(A2) The weight average molecular weight is 50,000 to 700,000.

  [2] The thermoplastic elastomer composition according to [1], further including 0.05 to 5 parts by mass of (D) a surface treatment agent with respect to 100 parts by mass of the (C) thermal conductive filler.

  [3] The blending amount of the (B) liquid component is 20 to 500 parts by mass with respect to 100 parts by mass of the (A) hydrogenated diene copolymer, as described in [1] or [2] Thermoplastic elastomer composition.

  [4] The thermoplastic elastomer composition according to any one of [1] to [3], wherein the liquid component (B) includes the softening agent and the liquid polymer.

  [5] The thermoplastic elastomer composition according to [4], wherein the liquid polymer is liquid polybutene.

  [6] The thermoplastic elastomer composition according to any one of [2] to [5], wherein the (D) surface treatment agent is a saturated fatty acid.

  [7] A thermally conductive sheet comprising the thermoplastic elastomer composition according to any one of [1] to [6].

  [8] The heat conductive sheet according to [7], wherein the thickness is 0.1 to 3 mm.

  The thermoplastic elastomer composition of the present invention is a molded product that is excellent in flexibility, heat resistance, cold resistance, thermal conductivity, adhesion, reworkability, recyclability, and does not generate siloxane vapor even when heated under predetermined conditions. Is produced.

  The heat conductive sheet of the present invention is excellent in flexibility, heat resistance, cold resistance, heat conductivity, adhesion, reworkability, recyclability, and no siloxane vapor is generated even when heated under predetermined conditions. There is an effect.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. It is understood that the scope of the present invention includes modifications, improvements, and the like as appropriate to the following embodiments based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should. In this specification, the 3,4-bond of the conjugated diene polymer is regarded as the same as the 1,2-vinyl bond, and the vinyl bond content includes both 1,2-bond content and 3,4-bond content. Shall be included.

I. Thermoplastic elastomer composition:
The thermoplastic elastomer composition of the present invention contains (A) a hydrogenated diene copolymer, (B) a liquid component, and (C) a thermally conductive filler. (A) Since the hydrogenated diene copolymer is excellent in flexibility, a molded article excellent in adhesion can be produced.

1. (A) Hydrogenated diene copolymer:
(A) The hydrogenated diene copolymer satisfies the conditions (A1) and (A2), and is a polymer block (i) (hereinafter sometimes simply referred to as “(i)”). A polymer block (ii) (hereinafter sometimes simply referred to as “(ii)”), and a structure represented by (i)-(ii)-(i) (where (i ) Represents a polymer block (i), and (ii) represents a hydrogenated block copolymer having a polymer block (ii).
(A1) The hydrogenation rate of double bonds derived from conjugated dienes is 80% or more.
(A2) The weight average molecular weight is 50,000 to 700,000.

(Block copolymer)
The block copolymer has a polymer block (i) containing a structural unit derived from the first conjugated diene compound and a polymer block (ii) containing a structural unit derived from the second conjugated diene compound. And (i)-(ii)-(i) (wherein (i) represents a polymer block (i) and (ii) represents a polymer block (ii)) And the content of the polymer block (i) is 5 to 90% by mass with respect to the total of the polymer block (i) and the polymer block (ii), and the content of the polymer block (ii) The ratio is 10 to 95% by mass.

(1) Polymer block (i):
The polymer block (i) is a polymer block containing a structural unit derived from the first conjugated diene compound and having a vinyl bond content of less than 25%. Although it does not specifically limit as a 1st conjugated diene compound, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3 -Pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene and the like can be mentioned. Among these, 1,3-butadiene is particularly preferable. That is, the polymer block (i) is a 1,3-butadiene polymer block containing 1,3-butadiene as a main constituent (90% by mass or more, preferably 95% by mass or more of the entire polymer block (i)). It is preferable that

  The vinyl bond content of the polymer block (i) is less than 25%, preferably 20% or less, more preferably 15% or less. When the vinyl bond content of the polymer block (i) is 25% or more, the melting point of the crystal of the (A) hydrogenated diene copolymer after hydrogenation is remarkably lowered and the reworkability is lowered, which is not preferable.

  The weight average molecular weight of the polymer block (i) is preferably 25,000 to 630,000, and more preferably 30,000 to 480,000. The polymer block (i) becomes a polymer block having a structure similar to that of low-density polyethylene after hydrogenation, that is, in the (A) hydrogenated diene copolymer.

(2) Polymer block (ii):
The polymer block (ii) is a conjugated diene polymer block having a structural unit derived from the second conjugated diene compound and having a vinyl bond content of 40% or more. Examples of the second conjugated diene compound include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and 1,3-hexadiene. 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene and the like. Among these, 1,3-butadiene, isoprene and 1,3-pentadiene are preferable, and 1,3-butadiene is particularly preferable. In addition, polymer block (ii) may be comprised from 2 or more types of 2nd conjugated diene compounds.

  Moreover, the polymer block (ii) may further have a structural unit derived from a vinyl aromatic compound. However, it is preferable that the structural unit derived from the second conjugated diene compound is a main structural component (50% by mass or more, preferably 60% by mass or more of the entire polymer block (ii)).

  Examples of vinyl aromatic compounds include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylstyrene, vinylnaphthalene, vinylanthracene, and N, N-diethyl. -P-aminoethylstyrene, vinylpyridine, etc. can be mentioned. Among these, styrene is particularly preferable.

  The content ratio of the structural unit derived from the vinyl aromatic compound is preferably 35% by mass or less, and more preferably 30% by mass or less, when the entire polymer block (ii) is 100% by mass. 25% by mass or less is particularly preferable. When the content ratio of the structural unit derived from the vinyl aromatic compound increases, the glass transition temperature of the (A) hydrogenated diene copolymer increases, and the cold resistance, flexibility, and adhesion of the molded product tend to decrease. is there.

  The vinyl bond content of the polymer block (ii) is 40% or more, preferably 40 to 95%, more preferably 40 to 90%, and particularly preferably 45 to 80%. When the vinyl bond content of the polymer block (ii) is less than 40%, the cold resistance of the molded product may be inferior, which is not preferable. On the other hand, if it exceeds 95%, the productivity is undesirably lowered.

  The weight average molecular weight of the polymer block (ii) is preferably 25,000 to 650,000, and more preferably 30,000 to 540,000. The polymer block (ii) is hydrogenated, that is, in the (A) hydrogenated diene copolymer, the rubbery ethylene / butene-1 copolymer block or vinyl aromatic compound / ethylene -It becomes a polymer block which shows a structure similar to a butene-1 copolymer.

  The block copolymer has a structure represented by (i)-(ii)-(i). After hydrogenating the block copolymer having such a structure, that is, in the (A) hydrogenated diene copolymer, both ends have a structure similar to low-density polyethylene, and thus have crystallinity, Since the middle shows a similar structure to a rubbery ethylene-butene-1 copolymer block, etc., it is excellent in flexibility.

  In the block copolymer, the coupling agent residue has a sufficiently small molecular weight relative to the polymer block (i) and the polymer block (ii), and (A) the crystallinity of the hydrogenated diene copolymer. ((I)-(ii)) n-X-((ii)-(i)) (where n is 1 and X represents a coupling agent residue). ) May be used. That is, when a relatively small coupling agent residue is abbreviated, the structure is represented by (i)-(ii)-(i).

  In the block copolymer, the content of the polymer block (i) is 5 to 90% by mass and 10 to 80% by mass with respect to the total of the polymer block (i) and the polymer block (ii). It is preferable. That is, the content of the polymer block (ii) is 10 to 95% by mass, and preferably 20 to 90% by mass. When the polymer block (i) is less than 5% by mass (that is, the polymer block (ii) exceeds 95% by mass), the reworkability of the (A) hydrogenated diene copolymer is lowered, which is not preferable. On the other hand, when the polymer block (i) is more than 95% by mass (that is, the polymer block (ii) is less than 5% by mass), the hardness of the (A) hydrogenated diene copolymer excessively increases. That is, it is not preferable because it is inferior in flexibility.

(Preparation method)
A hydrogenated diene copolymer is obtained by combining a vinyl aromatic compound and a conjugated diene compound, or a vinyl aromatic compound and a conjugated diene compound and other monomers copolymerizable with these in an inert organic solvent. It can be prepared by using a compound as a polymerization initiator, carrying out living anion polymerization to obtain a block copolymer, and hydrogenating the obtained block copolymer. Examples of the inert organic solvent include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, and octane; alicyclic hydrocarbon solvents such as cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane; benzene, xylene, toluene, There are aromatic hydrocarbon solvents such as ethylbenzene.

  Examples of the organic alkali metal compound used as the polymerization initiator include organic lithium compounds and organic sodium compounds. In particular, organic lithium compounds such as n-butyllithium, sec-butyllithium, and tert-butyllithium are preferable. There is no particular limitation on the amount of the organic alkali metal compound used, and various amounts can be selected as necessary, but the amount used is 0.02 to 15% by mass with respect to the total of 100% by mass of the monomers. It is preferable that the amount used is 0.03 to 5% by mass.

  The polymerization temperature is preferably −10 to 150 ° C., more preferably 0 to 120 ° C. The polymerization atmosphere is preferably replaced with an inert gas such as nitrogen. The polymerization pressure is not particularly limited as long as it is carried out within a range of pressure sufficient to maintain the monomer and solvent in the liquid phase under these polymerization conditions.

  Further, in the process of polymerizing a copolymer block having a structural unit derived from a vinyl aromatic compound and a conjugated diene compound, the method of introducing the monomer of the compound into the polymerization system is not particularly limited, and is collectively and continuously. It can be performed by a method that is automatic, intermittent, or a combination thereof. Furthermore, when polymerizing a copolymer block having a structural unit derived from a vinyl aromatic compound and a conjugated diene compound, the addition amount of other monomers, the addition amount of a polar substance, the number and type of polymerization containers, In addition, the use of the monomer may be appropriately selected so that the physical properties of the resulting hydrogenated diene copolymer, its composition, and the molded article of the composition are preferable.

  The block copolymer may be a copolymer in which the molecular chain of the (co) polymer block is coupled via a coupling residue using a coupling agent after living anionic polymerization.

  Examples of the coupling agent include divinylbenzene, 1,2,4-trivinylbenzene, epoxidized 1,2-polybutadiene, epoxidized soybean oil, epoxidized linseed oil, and benzene-1,2,4-triisocyanate. , Diethyl oxalate, diethyl malonate, diethyl adipate, dioctyl adipate, dimethyl phthalate, diethyl phthalate, diethyl terephthalate, diethyl carbonate, 1,1,2,2-tetrachloroethane, 1,4-bis (trichloro Methyl) benzene, trichlorosilane, methyltrichlorosilane, butyltrichlorosilane, tetrachlorosilane, (dichloromethyl) trichlorosilane, hexachlorodisilane, tetraethoxysilane, tetrachlorotin, 1,3-dichloro-2-propanone, etc. it can. Among these, divinylbenzene, epoxidized 1,2-polybutadiene, trichlorosilane, methyltrichlorosilane, and tetrachlorosilane are preferable.

  (A) The hydrogenated diene copolymer is obtained by partially or selectively hydrogenating such a block copolymer. The hydrogenation method and reaction conditions are not particularly limited. For example, the hydrogenation is performed at 20 to 150 ° C. under hydrogen pressure of 0.1 to 10 MPa in the presence of a hydrogenation catalyst. In this case, the hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, or the reaction time.

  Examples of the hydrogenation catalyst include compounds containing any one of Group Ib, IVa, Va, VIa, VIIa, and Group VIII metals, such as Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, and Re. , Compounds containing Pt atoms can be used. Specifically, for example, metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, and Re; metals such as Pd, Ni, Pt, Rh, and Ru are carbon, silica, and alumina. A supported heterogeneous catalyst supported on a carrier such as diatomaceous earth; a homogeneous Ziegler catalyst in which an organic salt of a metal element such as Ni or Co or an acetylacetone salt and a reducing agent such as organoaluminum is combined; Ru, Rh Organometallic compounds or complexes such as: fullerenes occluded with hydrogen and carbon nanotubes. In addition, a hydrogenation catalyst may be used individually by 1 type, and can also be used in combination of 2 or more type.

  Among these, a metallocene compound containing any of Ti, Zr, Hf, Co, and Ni is preferable in that it can be hydrogenated in a homogeneous system in an inert organic solvent. Furthermore, a metallocene compound containing any of Ti, Zr, and Hf is preferable. In particular, a hydrogenation catalyst obtained by reacting a titanocene compound with an alkyl lithium is preferable because it is an inexpensive and industrially useful catalyst.

  The amount of the hydrogenation catalyst used is preferably 0.005 to 0.05 mol%, more preferably 0.008 to 0.03 mol%, more preferably 0.01 to 0.03 mol%, based on the total amount of the conjugated diene compound. Particularly preferred is 0.02 mol%.

  After hydrogenation using a hydrogenation catalyst, the catalyst residue is removed as necessary, or a phenol-based or amine-based antioxidant is added, and then hydrogenated from the hydrogenated diene copolymer solution. A diene copolymer is isolated. Isolation of the hydrogenated diene copolymer can be carried out, for example, by adding acetone or alcohol to the hydrogenated diene copolymer solution and precipitating, or by adding the hydrogenated diene copolymer solution to hot water with stirring. The solvent can be removed by distillation.

  The hydrogenated diene copolymer may be a modified hydrogenated diene copolymer modified with a functional group. Examples of the functional group include at least one functional group selected from the group consisting of a carboxyl group, an acid anhydride group, a hydroxyl group, an epoxy group, a halogen atom, an amino group, an isocyanate group, a sulfonyl group, and a sulfonate group. The modification method can be performed by a known method.

  Preferred monomers that can be used to introduce functional groups include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, hydroxyethyl methacrylate, hydroxypropyl Examples include methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and dimethylaminoethyl methacrylate.

  In addition, the content ratio of the functional group in the modified hydrogenated diene copolymer is preferably 0.01 to 10 mol% when the entire constitutional unit constituting the block copolymer is 100 mol%, and 0 More preferably, it is 1-8 mol%, and it is especially preferable that it is 0.15-5 mol%.

(Physical properties)
The double bonds present in the hydrogenated diene copolymer are saturated with at least 80% of all double bonds before hydrogenation. If it is less than 80%, the heat resistance and durability of the molded product may be easily lowered. In addition, as for a double bond, it is still more preferable that 90% or more is saturated, and it is especially preferable that 95-100% is saturated.

  The number average molecular weight of the hydrogenated diene copolymer is preferably 50,000 to 700,000, and more preferably 100,000 to 600,000. If it is less than 50,000, heat resistance and reworkability may be deteriorated. On the other hand, if it exceeds 700,000, the workability tends to decrease.

2. (B) Liquid component:
(B) A liquid component is at least 1 type selected from the group which consists of a softener, a plasticizer, and a liquid polymer. Specific examples of softeners include mineral oils such as paraffinic oils, naphthenic oils and aromatic oils, synthetic oils such as ethylene / α-olefin oligomers, fatty acids such as oleic acid and ricinoleic acid, castor oil, cottonseed oil And vegetable oils such as linseed oil, rapeseed oil, soybean oil, palm oil and peanut oil.

  Specific examples of plasticizers include phthalic acid derivatives, isophthalic acid derivatives, tetrahydrophthalic acid derivatives, adipic acid derivatives, sebacic acid derivatives, fumaric acid derivatives, citric acid derivatives, azelaic acid derivatives, phosphoric acid derivatives, maleic acid derivatives, etc. Examples include various fatty acid derivatives.

  Specific examples of the liquid polymer include (modified) liquid polybutadiene, (modified) liquid isoprene, liquid polybutene, (modified) liquid styrene / butadiene rubber, polyisobutylene, and silicone oil.

  (B) It is preferable to use a liquid component in combination with a softening agent and a liquid polymer because a thermoplastic elastomer composition capable of producing a molded article having excellent flexibility can be obtained. From the viewpoint of the heat resistance of the molded product, it is particularly preferable to use liquid polybutene as the liquid polymer.

  (B) The compounding quantity of a liquid component is 5-1000 mass parts with respect to 100 mass parts of (A) hydrogenated diene copolymer, Preferably it is 10-800 mass parts, More preferably, 20- 500 parts by mass. If the blending amount is less than 5 parts by mass, the flexibility of the molded product may decrease. On the other hand, if it exceeds 1000 parts by mass, the reworkability of the thermally conductive sheet is lowered, and the thermoplastic elastomer composition cannot be molded, which is not preferable.

3. (C) Thermally conductive filler:
(C) As a heat conductive filler, there exist carbon type material, metal type material, ceramic type material, silica type material, and these composite materials, for example. Specific examples of carbon materials include furnace blacks such as ketjen black; carbon blacks such as acetylene black, channel black and gas black; carbon fibers such as PAN carbon fibers, pitch carbon fibers and rayon carbon fibers; Examples thereof include graphite such as graphite, flaky graphite, massive graphite, and earthy graphite; diamond, fullerene, carbon microcoil, carbon nanotube, graphene, and the like.

  Specific examples of metal materials include silver powder, gold powder, copper powder, iron powder, stainless steel powder, nickel powder, aluminum powder, platinum powder, and other metal powders; alumina, magnesium oxide, zinc oxide, antimony oxide, indium oxide, and the like. Metal oxides: Metal fibers such as copper fibers, stainless steel fibers, aluminum fibers and nickel fibers can be mentioned. Specific examples of the ceramic material include ceramics such as boron nitride, aluminum nitride, silicon nitride, alumina-titanium carbide ceramic, zirconia ceramic, and silicon carbide.

  Specific examples of the silica-based material include silica powder such as quartz, crystalline silica, and amorphous silica. Specific examples of the composite material whose surface is coated include glass, silica, polymer particles and the like coated with the carbon material, metal material, ceramic material, or silica material.

  For the purpose of improving the wettability with the (A) hydrogenated diene copolymer serving as a matrix, it is preferable to use a surface-treated (C) thermally conductive filler. There is no restriction | limiting in particular about the surface treatment method of a heat conductive filler, (C) A heat conductive filler and (D) surface treating agent may be mixed previously, (A) Hydrogenated diene type copolymer, ( B) Liquid component, (C) thermally conductive filler, and (D) surface treatment agent may be mixed together. In addition, these (C) heat conductive fillers can be used individually by 1 type or in combination of 2 or more types.

  (C) The shape of the heat conductive filler is not particularly limited. Specific examples of the shape include a spherical shape, a needle shape, a fiber shape, a scale shape, a dendritic shape, a flat plate shape, and an indefinite shape. When the aspect ratio of the thermally conductive filler (C) such as boron nitride or carbon fiber is larger than 1 and there is anisotropy in the thermal conductivity, the electric field, magnetic field, shear field, gravity field, and combinations thereof ( C) A thermally conductive filler can be oriented to give thermal conductivity anisotropy to the molded article of the obtained thermoplastic elastomer composition. Specific examples of the shear field include extrusion molding, roll molding, injection molding, and foam molding.

  (C) The number average particle diameter of the thermally conductive filler is preferably 0.01 to 500 μm, more preferably 0.1 to 400 μm, and particularly preferably 1 to 300 μm. (C) If the number average particle size of the thermally conductive filler is too small, the viscosity of the resulting thermoplastic elastomer composition may increase, and the processability may be significantly reduced. On the other hand, if the number average particle diameter of (C) the thermally conductive filler is too large, the design of the molded article of the elastomer composition obtained may be lowered.

  (C) The compounding quantity of a heat conductive filler is 20-80 volume parts with respect to 100 volume parts of thermoplastic elastomer compositions, Preferably it is 30-75 volume parts, More preferably, it is 35-70 volume parts. It is. If the blending amount is less than 20 parts by volume, the thermal conductivity of the molded product may be low. On the other hand, if it exceeds 80 parts by volume, the volume flexibility and workability of the molded product will be unfavorable.

  (C) When metal hydroxides, such as aluminum hydroxide and magnesium hydroxide, are used as a heat conductive filler, a flame retardance can be provided to the obtained thermoplastic elastomer composition. In addition, brominated flame retardants such as tetrabromobisphenol A and decabromodiphenyl ether; red phosphorus, aromatic phosphate ester, aromatic condensed phosphate ester, halogenated phosphoric acid, if necessary, in order to improve flame retardancy Phosphorus flame retardants such as esters; antimony trioxide, silicone flame retardants and the like may be added. Further, short silicon nitride fibers or the like may be added to prevent drip.

4). (D) Surface treatment agent:
(D) The surface treatment agent improves the thermal conductivity and flexibility by improving the dispersibility of the (C) thermal conductive filler. For example, there are fatty acid, fatty acid ester, fatty acid metal salt, hydrogenated oil, silane coupling agent, titanate coupling agent and the like. Specific examples of fatty acids include stearic acid, oleic acid, palmitic acid, linoleic acid, lauric acid, caprylic acid, behenic acid, montanic acid, castor oil, linseed oil and the like.

  Specific examples of fatty acid esters include methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl erucate, methyl behenate, butyl laurate, butyl stearate, isopropyl myristate, palmitic acid Monoesters such as isopropyl, octyl palmitate, octyl palm fatty acid, octyl stearate, special beef tallow fatty acid octyl ester, lauryl laurate, stearyl long stearate, long chain fatty acid higher alcohol ester, behenyl behenate, cetyl myristate; neo Pentyl polyol long chain fatty acid ester, neopentyl polyol long chain fatty acid ester partially esterified product; neopentyl polyol fatty acid ester, neopentyl polyol medium chain fatty acid ester Ether, neopentyl polyol C9 chain fatty acid esters, dipentaerythritol long chain fatty acid ester, and special fatty acid esters such as complex medium chain fatty acid esters.

  Specific examples of fatty acid metal salts include metal salts such as stearic acid, oleic acid, palmitic acid, linoleic acid, lauric acid, caprylic acid, behenic acid, and montanic acid, and the metals include Na, K, Al, and Ca. Mg, Zn, Ba, Co, Sn, Ti, Fe, etc. can be mentioned. Specific examples of the hardened oil include beef tallow hardened oil and castor hardened oil.

  Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltrichlorosilane, vinyltriacetoxysilane, N- (β-aminoethyl) -γ-amino. Propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltris (β-methoxyethoxy) silane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxylane, methyltriethoxy Orchids, hexamethyldisilazane, .gamma. anilino trimethoxysilane, mention may be made of N- [beta-(N- vinyl benzal amino) ethyl] -γ- aminopropyltrimethoxysilane hydrochloride and the like.

  Specific examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri (N-aminoethyl aminoethyl) titanate, diisopropyl bis (dioctyl phosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (Ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, etc. Can be mentioned.

  Of these, saturated fatty acids are particularly preferred because of their excellent heat resistance. In addition, (D) surface treating agent can be used individually by 1 type or in combination of 2 or more types.

  (D) The compounding quantity of a surface treating agent becomes like this. Preferably it is 0.05-5 mass parts with respect to 100 mass parts of (C) thermal conductive filler, More preferably, it is 0.05-2 mass parts. When the blending amount is less than 0.05 parts by mass, the effect of adding the surface treatment agent (D) may be insufficient. On the other hand, if it exceeds 5 parts by mass, the reworkability of the thermal conductive sheet is lowered and bleeding of the liquid component (B) is not preferable.

5). Other ingredients:
The thermoplastic elastomer composition of the present invention may contain various additives as necessary. Examples of such additives include foaming agents, lubricants, anti-aging agents, heat stabilizers, HALS and other light resistance agents, weather resistance agents, metal deactivators, UV absorbers, light stabilizers, copper damage prevention agents, and the like. Stabilizers, antibacterial agents, antifungal agents, dispersants, flame retardants, tackifiers, colorants such as titanium oxide, carbon black and organic pigments, glass cloth, fibers such as aramid fibers, potassium titanate whiskers, etc. Inorganic whiskers, glass beads, glass balloons, glass flakes, asbestos, mica, calcium carbonate, talc, calcium silicate, hydrotalcite, kaolin, diatomaceous earth, pumice, evo powder, cotton flock, cork powder, barium sulfate, fluorine Fillers such as resin, polymer beads, polyolefin wax, cellulose powder, rubber powder, wood powder or mixtures thereof, ethylene Pyrene copolymers, isobutylene-isoprene copolymers, rubbers such as silicone rubber may contain polyethylene, polypropylene, thermoplastic resins such as ethylene-vinyl acetate copolymer.

II. Thermal conductive sheet:
The heat conductive sheet of the present invention is formed by molding the thermoplastic elastomer composition described in “I. Thermoplastic elastomer composition”. As the molding method, a known method such as extrusion molding, press molding, injection molding, roll molding, roll press molding can be used. Since the heat conductive sheet of the present invention has good adhesion, there are few gaps between a heat generating part and a heat radiating part of an electronic device or the like, and the heat conductive efficiency is good. Although the thickness of a heat conductive sheet is not specifically limited, Usually, it is 0.1-3 mm, Preferably it is 0.1-0.8 mm, Most preferably, it is 0.2-0.5 mm.

  The heat conductive sheet of the present invention may further include other members. For example, the thermally conductive sheet of the present invention may have a protective film on at least one surface thereof. That is, a protective film may be provided on one side or both sides of the heat conductive sheet of the present invention. The protective film is provided for peeling off during use. The protective film may be a single layer or a multilayer.

  The constituent material of the protective film is not particularly limited. Examples of the constituent material of the protective film include α-olefins such as paper, polyethylene, polypropylene, ethylene / propylene copolymer, polybutene, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, and ionomer. Examples thereof include homopolymers or copolymers, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyimide, and thermoplastic elastomers. Moreover, the thickness of this protective film is 10-1000 micrometers normally, Preferably it is 10-500 micrometers, More preferably, it is 10-100 micrometers.

  In order to facilitate the release of the protective film, a silicone-based or fluorine-based release coat layer can be provided between the protective film and the heat conductive sheet of the present invention. Furthermore, the surface of the heat conductive sheet of the present invention on which the protective film is provided may have irregularities. Furthermore, the heat conductive sheet of the present invention may have a support layer. That is, you may have the structure where the heat conductive sheet of this invention was arrange | positioned on both surfaces of the support layer. The constituent material of the support layer is not particularly limited. Examples of the constituent material of the support layer include the constituent materials described in the protective film, glass cloth, metal mesh, and the like. Moreover, the thickness of this support layer is the same as that of the said protective film, However The thinner one is preferable from a viewpoint of heat conduction efficiency.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Vinyl bond content (%)]: Calculated by the Hampton method using infrared analysis.

  [Melt flow rate (g / 10 min)]: Measured according to JIS K7210.

  [Weight average molecular weight (Mw)]: Calculated in terms of polystyrene using gel permeation chromatography (GPC, trade name: HLC-8120GPC, manufactured by Tosoh Finechem, column: manufactured by Tosoh, GMH-XL).

[Hydrogenation rate (%)]: Calculated from a 270 MHz, ¹ H-NMR spectrum using a carbon tetrachloride solution.

  [Hardness (Duro A)]: Based on JIS K6253, the hardness (after 10 seconds) of the heat conductive sheet was measured and used as an index of flexibility.

  [Heat resistance]: The heat conductive sheet was put into a gear oven (trade name “ACR60” manufactured by Toyo Seiki Seisakusho Co., Ltd.) and subjected to a heat resistance test at 100 ° C. for 500 hours. Subsequently, it was left still for one day under the conditions of 23 ° C. and 50% relative humidity, and the hardness (duro A) was measured in the same manner as described above to obtain a heat resistance index. It can be said that the smaller the numerical change in hardness (duro A) and heat resistance, the better the heat resistance.

[Cold Resistance]: A heat conductive sheet was put into a low temperature bath (Tabai Co., Ltd.) and a cold resistance test was conducted at −40 ° C. for 500 hours. Subsequently, the heat conductive sheet was taken out from the low temperature bath, and the appearance of the sheet was visually observed. At this time, cold resistance was evaluated by the following indices.
X: Bleed of liquid component (B) is observed in the heat conductive sheet.
○: Bleed of liquid component (B) is not observed in the heat conductive sheet.

  [Thermal conductivity (W / mK)]: The thermal conductivity of the thermal conductive sheet was measured in accordance with JIS R1611.

[Adhesion]: Using a pressure-bonding roller (roller mass: 2000 g) based on JIS Z0237, a thermally conductive sheet cut to 10 mm × 100 mm was bonded to a SUS304 plate that had been polished and finished with No. 240 according to JIS R6001. The SUS304 plate was tilted so that the bonding surface was vertical, and the bonding surface was visually observed to evaluate the adhesion with the following indicators.
X: Desorption or deviation is observed in the heat conductive sheet.
○: No desorption or deviation is observed in the heat conductive sheet.

[Reworkability]: The heat conductive sheet bonded to the SUS304 plate was peeled off from the SUS304 plate, and the reworkability was evaluated using the following indices.
X: The length of the heat conductive sheet after peeling is 103 mm or more.
(Circle): The length of the heat conductive sheet after peeling is less than 103 mm.

[Recyclability]: The heat conductive sheet was put into a pressure kneader heated to 150 ° C., kneaded at 40 rpm for 20 minutes, the state of the kneaded product was visually observed, and the recyclability was evaluated with the following indices.
X: The heat conductive sheet is not uniformly melted or dispersed.
○: The heat conductive sheet is uniformly melted and dispersed.

  [Siloxane generation amount (ppm)]: Using a headspace-gas chromatography-mass spectrometer (trade name “HP6890”, manufactured by Hewlett-Packard Company), the heat conductive sheet is heated at 100 ° C. for 30 minutes in the generated gas. The amount of siloxane generation contained in was measured.

(Synthesis Example 1: Preparation of hydrogenated diene copolymer (A-1))
Into a reaction vessel having an internal volume of 50 L purged with nitrogen, 24 kg of cyclohexane, 1 g of tetrahydrofuran (hereinafter also referred to as “THF”), 1200 g of 1,3-butadiene, and 3.3 g of n-butyllithium are added, and heat insulation from 70 ° C. Polymerization was performed. After completion of the reaction, the temperature was set to 5 ° C., and 340 g of THF and 2800 g of 1,3-butadiene were added to perform adiabatic polymerization. After 30 minutes, 2.3 g of methyldichlorosilane was added and reacted for 15 minutes. After completion of the reaction, hydrogen gas was supplied at a pressure of 0.4 MPa-G, stirred for 20 minutes, and reacted with lithium at the polymer terminal remaining as a living anion species to obtain lithium hydride.

  Thereafter, the reaction solution was set to 90 ° C., 7.2 g of tetrachlorosilane was added, and the mixture was stirred for about 20 minutes. Then, a hydrogenation catalyst was added, and a hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa for 2 hours. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure and extracted from the reaction vessel, and then the reaction solution is stirred into water and the solvent is removed by steam distillation to obtain (i)-( A hydrogenated diene copolymer (A-1) having a structure ii)-(i) was obtained.

  The hydrogenated diene copolymer (A-1) obtained had a hydrogenation rate of 99%, a weight average molecular weight (Mw) of 300,000, and the melt flow rate measured at 230 ° C. and 21.2 N was 2.5 g / 10 min. In addition, in the block copolymer before hydrogenation, the vinyl bond content of the polymer block (i) was 15%, and the vinyl bond content of the polymer block (ii) was 78%.

(Synthesis Example 2: Preparation of hydrogenated diene copolymer (A-2))
24 kg of cyclohexane, 1 g of THF, 1000 g of 1,3-butadiene, and 2.8 g of n-butyllithium were added to a reaction vessel having an internal volume of 50 L purged with nitrogen, and adiabatic polymerization was performed from 70 ° C. After completion of the reaction, the temperature was set to 40 ° C., and 100 g of THF and 3000 g of 1,3-butadiene were added to perform adiabatic polymerization. After 30 minutes, 2.2 g of methyldichlorosilane was added and reacted for 15 minutes. After completion of the reaction, hydrogen gas was supplied at a pressure of 0.4 MPa-G, stirred for 20 minutes, and reacted with lithium at the polymer terminal remaining as a living anion species to obtain lithium hydride.

  Thereafter, the reaction solution was set to 90 ° C., 7.2 g of tetrachlorosilane was added, and the mixture was stirred for about 20 minutes. Then, a hydrogenation catalyst was added, and a hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa for 2 hours. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure and extracted from the reaction vessel, and then the reaction solution is stirred into water and the solvent is removed by steam distillation to obtain (i)-( A hydrogenated diene copolymer (A-2) having a structure ii)-(i) was obtained.

  The hydrogenated diene copolymer (A-2) obtained had a hydrogenation rate of 99%, a weight average molecular weight (Mw) of 320,000, and the melt flow rate measured at 230 ° C. and 98.1 N was 3.5 g / 10 min. In addition, in the block copolymer before hydrogenation, the vinyl bond content of the polymer block (i) was 15%, and the vinyl bond content of the polymer block (ii) was 50%.

(Synthesis Example 3: Preparation of hydrogenated diene copolymer (A-3))
24 kg of cyclohexane, 1 g of THF, 1200 g of 1,3-butadiene, and 3.2 g of n-butyllithium were added to a reaction vessel having an internal volume of 50 L purged with nitrogen, and adiabatic polymerization was performed from 70 ° C. After completion of the reaction, the temperature was set to 35 ° C., and 26 g of THF and 2800 g of 1,3-butadiene were added to perform adiabatic polymerization. After 30 minutes, 2.4 g of methyldichlorosilane was added and reacted for 15 minutes. After completion of the reaction, hydrogen gas was supplied at a pressure of 0.4 MPa-G, stirred for 20 minutes, and reacted with lithium at the polymer terminal remaining as a living anion species to obtain lithium hydride.

  Thereafter, the reaction solution was brought to 80 ° C., 7.2 g of tetrachlorosilane was added, and the mixture was stirred for about 20 minutes. Then, a hydrogenation catalyst was added, and a hydrogenation reaction was performed at a hydrogen pressure of 1.0 MPa for 2 hours. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure and extracted from the reaction vessel, and then the reaction solution is stirred into water and the solvent is removed by steam distillation to obtain (i)-( A hydrogenated diene copolymer (A-3) having a structure ii)-(i) was obtained.

  The hydrogenated diene copolymer (A-3) obtained had a hydrogenation rate of 99%, a weight average molecular weight (Mw) of 290,000, and the melt flow rate measured at 230 ° C. and 98.1 N was It was 4.2 g / 10 min. In the block copolymer before hydrogenation, the vinyl bond content of the polymer block (i) was 15%, and the vinyl bond content of the polymer block (ii) was 35%.

(Synthesis Example 4: Preparation of hydrogenated diene copolymer (A-4))
24 kg of cyclohexane, 100 g of THF, 1200 g of 1,3-butadiene, and 3.3 g of n-butyllithium were added to a reaction vessel having an internal volume of 50 L purged with nitrogen, and adiabatic polymerization was performed from 40 ° C. After completion of the reaction, the temperature was set to 5 ° C. and 240 g of THF and 2800 g of 1,3-butadiene were added to perform adiabatic polymerization. After 30 minutes, 2.3 g of methyldichlorosilane was added and reacted for 15 minutes. After completion of the reaction, hydrogen gas was supplied at a pressure of 0.4 MPa-G, stirred for 20 minutes, and reacted with lithium at the polymer terminal remaining as a living anion species to obtain lithium hydride.

  Thereafter, the reaction solution was set to 90 ° C., 7.2 g of tetrachlorosilane was added, and the mixture was stirred for about 20 minutes. Then, a hydrogenation catalyst was added, and a hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa for 2 hours. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure and extracted from the reaction vessel, and then the reaction solution is stirred into water and the solvent is removed by steam distillation to obtain (i)-( A hydrogenated diene copolymer (A-4) having a structure ii)-(i) was obtained.

  The hydrogenated diene copolymer (A-4) obtained had a hydrogenation rate of 99%, a weight average molecular weight (Mw) of 300,000, and the melt flow rate measured at 230 ° C. and 21.2 N was 9.5 g / 10 min. In the block copolymer before hydrogenation, the vinyl bond content of the polymer block (i) was 45%, and the vinyl bond content of the polymer block (ii) was 80%.

(Synthesis Example 5: Preparation of hydrogenated diene copolymer (A'-8))
24 kg of cyclohexane, 1 g of THF, 1,200 g of 1,3-butadiene, and 3.3 g of n-butyllithium were added to a reaction vessel having an internal volume of 50 L purged with nitrogen, and adiabatic polymerization was performed from 70 ° C. After completion of the reaction, the temperature was set to 5 ° C., and 340 g of THF and 2800 g of 1,3-butadiene were added to perform adiabatic polymerization. After 30 minutes, hydrogen gas was supplied at a pressure of 0.4 MPa-G, stirred for 20 minutes, and reacted with lithium at the polymer terminal remaining as a living anion species to obtain lithium hydride.

  Thereafter, the reaction solution was set to 90 ° C., 7.2 g of tetrachlorosilane was added, and the mixture was stirred for about 20 minutes. Then, a hydrogenation catalyst was added, and a hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa for 2 hours. When the absorption of hydrogen is completed, the reaction solution is returned to room temperature and normal pressure and extracted from the reaction vessel, and then the reaction solution is stirred into water and the solvent is removed by steam distillation to obtain (i)-( ii) A hydrogenated diene copolymer (A′-8) having a structure was obtained. The resulting hydrogenated diene copolymer (A′-8) had a hydrogenation rate of 99%, a weight average molecular weight (Mw) of 160,000, and a melt flow rate measured at 230 ° C. and 21.2 N. Was 26 g / 10 min. In addition, in the block copolymer before hydrogenation, the vinyl bond content of the polymer block (i) was 15%, and the vinyl bond content of the polymer block (ii) was 78%.

(Example 1: Production of thermal conductive sheet (1))
100 parts of hydrogenated diene copolymer (A-1) prepared in Synthesis Example 1, 400 parts of liquid component (B-1-1), 2072 parts of thermal conductive filler (C-1), surface treatment agent (D -1) 3.0 parts and 0.5 parts of an anti-aging agent were charged into a pressure type kneader (capacity 1.5 L, manufactured by Moriyama Co., Ltd.) heated to 150 ° C in advance. A kneaded material in a molten state was obtained by kneading for 20 minutes at 40 rpm (shearing speed 200 / sec) until each component was uniformly dispersed. The obtained kneaded material was press-molded at 180 ° C. (Iwaki Kogyo Co., Ltd., heating / cooling press), and cooled to room temperature to produce a 0.5 mm-thick thermal conductive sheet (1).

  In addition, the hardness (duro A) of the manufactured heat conductive sheet (1) is less than 1, the heat resistance is less than 1, the evaluation of cold resistance is “◯”, and the heat conductivity is 1.2 W / The evaluation of adhesion was “◯”, the evaluation of reworkability was “◯ (102)”, the evaluation of recyclability was “◯”, and the amount of siloxane generated was 0 ppm.

(Examples 2 to 10: Production of thermally conductive sheets (2) to (10))
Each thermally conductive sheet was produced in the same manner as in Example 1 except that the formulation shown in Table 2 was used. The measurement result and evaluation result of each manufactured heat conductive sheet are shown together in Table 2.

(Examples 11 to 17: Production of thermally conductive sheets (11) to (17))
Each thermally conductive sheet was produced in the same manner as in Example 1 except that the formulation shown in Table 3 was used. The measurement result and evaluation result of each manufactured heat conductive sheet are shown together in Table 3.

(Example 18: Production of thermally conductive sheet (18))
A heat conductive sheet was produced in the same manner as in Example 1 except that the formulation shown in Table 3 was used and the sheet thickness was 3 mm. The measurement result and evaluation result of the manufactured heat conductive sheet are shown together in Table 3.

(Example 19: Production of thermally conductive sheet (19))
A heat conductive sheet was produced in the same manner as in Example 1 except that the formulation shown in Table 3 was used and the sheet thickness was 0.2 mm. The measurement result and evaluation result of the manufactured heat conductive sheet are shown together in Table 3.

(Comparative Examples 1 to 6: Production of thermally conductive sheets (20) to (25))
Each thermally conductive sheet was produced in the same manner as in Example 1 except that the formulation shown in Table 4 was used. The measurement result and evaluation result of each manufactured heat conductive sheet are shown together in Table 4. In Comparative Example 2, a heat conductive sheet could not be produced.

(Comparative Example 7: Production of thermally conductive sheet (26))
100 parts of silicone rubber (two-part liquid silicone rubber, manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KE-1950-10”, (A′-6)), 339 parts of heat conductive filler (C-1), surface treatment agent (D-1) 0.6 part and 0.1 part of anti-aging agent were put into a pressure type kneader previously heated to 40 ° C. and kneaded at 40 rpm for 20 minutes to obtain a kneaded product. The obtained kneaded product is poured into a press mold, press-molded at 120 ° C. for 5 minutes, press-cured, then post-cured in a gear oven heated to 150 ° C. for 1 hour, A heat conductive sheet (26) was produced. Table 4 shows the measurement results and evaluation results of the manufactured heat conductive sheet (26).

(Comparative Example 8: Production of thermally conductive sheet (27))
To a 3 L reaction vessel purged with nitrogen, 600 g of ethyl acetate, 474 g of n-butyl acrylate, 120 g of methoxyethyl acrylate, 6 g of 4-hydroxybutyl acrylate, and 1.2 g of azoisobutyronitrile were added, and the reaction vessel was heated to 60 ° C. The polymerization reaction was carried out for 6 hours with stirring. The reaction solution was reprecipitated and filtered with ethanol, and vacuum dried at 40 ° C. for 8 hours to obtain an acrylic rubber (A′-7). The weight average molecular weight of the acrylic rubber was 1.6 million.

  100 parts of the obtained acrylic rubber (A'-7), 517 parts of heat conductive filler (C-2), 0.6 part of surface treatment agent (D-1), 0.1 part of anti-aging agent, isocyanate-based curing 0.2 part of an agent (made by Nippon Polyurethane Industry Co., Ltd., trade name “Coronate L-75”) was put into a pressure type kneader preheated to 40 ° C. and kneaded at 40 rpm for 20 minutes to obtain a kneaded product. . The obtained kneaded material was press-molded at 40 ° C. and dried at 90 ° C. for 10 minutes. Then, it was cured for 7 days under the conditions of 23 ° C. and 60% RH to produce a 0.5 mm-thick thermal conductive sheet (27). Table 4 shows the measurement results and evaluation results of the manufactured heat conductive sheet (27).

(Comparative Example 9: Production of thermally conductive sheet (28))
A heat conductive sheet (28) was produced in the same manner as in Example 1 except that the formulation shown in Table 4 was used. The measurement results and evaluation results of the manufactured heat conductive sheet (28) are also shown in Table 4.

  Details of various components used in Examples and Comparative Examples are described below.

((A) Hydrogenated diene copolymer)
(A′-5); polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene, manufactured by Kuraray Co., Ltd., trade name “SEPTON 4077”, MFR (230 ° C., 98.1 N) = less than 0.1 g / 10 min, styrene content = 33%.

((B) Liquid component)
(B-1-1); mineral oil softener, Idemitsu Kosan Co., Ltd., trade name “PW-380”, kinematic viscosity at 40 ° C. = 381.6 mm ² / s.
(B-1-2); Synthetic mineral oil-based softener, manufactured by Idemitsu Kosan Co., Ltd., trade name “Linear Rendimer A-2020H”, kinematic viscosity at 40 ° C. = 5.0 mm ² / s.
(B-2-1): Liquid polybutene, manufactured by Nippon Oil Corporation, trade name “Nisseki Polybutene HV-1900”, kinematic viscosity at 40 ° C. = 16000 mm ² / s.
(B-2-2); terminal hydroxyl group-modified liquid isoprene, manufactured by Idemitsu Kosan Co., Ltd., trade name “Epol”, viscosity at 30 ° C. = 75 Pa · s.

((C) Thermally conductive filler)
(C-1); Aluminum hydroxide, manufactured by Shin Nippon Light Metal Co., Ltd., trade name “BF083”, average particle size 10 μm.
(C-2); Aluminum oxide, manufactured by Admatechs, trade name “Admafine AO509”, average particle size = 10 μm.
(C-3); Boron nitride, manufactured by Denka Co., Ltd., trade name “DENCABORON NITRIDE JP75”, average particle size = 25 μm.
(C-4); carbon fiber, manufactured by Teijin Ltd., trade name “Rahima A301”, average fiber diameter = 8 microns, average fiber length = 200 μm.

((D) Surface treatment agent)
(D-1); stearic acid, manufactured by Kao Corporation, trade name “Lunac S-50V”
(D-2); Linseed oil, manufactured by Nisshin Oillio Group, trade name “linseed oil”
(D-3); vinyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBE-1003”

(Anti-aging agent)
Pentaerythritol tetrakis [3- (3,5-ditert-butyl-4-hydroxyphenyl) propionate, manufactured by Ciba Japan, trade name “Irganox 1010”

  From the results shown in Tables 2 to 4, the thermal conductive sheets of Examples 1 to 19 are flexible, heat resistant, cold resistant, thermal conductivity, and adhesion as compared with the thermal conductive sheets of Comparative Examples 1 to 9. It can be seen that it has excellent properties, reworkability, recyclability, and low siloxane properties. On the other hand, the heat conductive sheet of Comparative Example 1 was inferior in adhesion because the liquid component (B) was not blended. Moreover, since the heat conductive sheet of the comparative example 3 was not mix | blended with the (C) heat conductive filler, heat conductivity was inferior. Since the heat conductive sheets of Comparative Examples 4 to 8 do not contain the (A) hydrogenated diene copolymer according to the present invention, Comparative Example 4 is inferior in cold resistance, and Comparative Examples 5 and 6 have reworkability. Inferior, Comparative Example 7 had poor recyclability and low siloxane properties, Comparative Example 8 had poor recyclability, and Comparative Example 9 had poor reworkability. In Comparative Example 2, since the blending amount of the liquid component (B) was large, the heat conductive filler was not uniformly dispersed, and a heat conductive sheet could not be produced.

  The thermoplastic elastomer composition of the present invention is excellent in flexibility, heat resistance, cold resistance, thermal conductivity, adhesion, reworkability, and recyclability, and can produce a molded product that does not generate siloxane vapor. This molded product can be used for a heat conductive sheet or the like used between a heat radiating portion and a heat generating portion of a semiconductor or the like whose size and performance are increasing.

Claims (8)

(A) a hydrogenated diene copolymer that satisfies the following conditions (A1) and (A2):
(B) at least one liquid component selected from the group consisting of softeners, plasticizers, and liquid polymers;
(C) a heat conductive filler,
The (B) liquid component is 5 to 1000 parts by mass with respect to 100 parts by mass of the (A) hydrogenated diene copolymer,
The (A) hydrogenated diene copolymer is
A polymer block (i) containing a structural unit derived from the first conjugated diene compound, and a polymer block (ii) containing a structural unit derived from the second conjugated diene compound, and (i)- A block copolymer having a structure represented by (ii)-(i) (where (i) represents a polymer block (i) and (ii) represents a polymer block (ii)). Hydrogenated,
The polymer block (i) is a polymer block having a vinyl bond content of less than 25%,
The polymer block (ii) is a polymer block having a vinyl bond content of 40% or more,
The block copolymer has a content ratio of the polymer block (i) of 5 to 90% by mass with respect to the total of the polymer block (i) and the polymer block (ii), and A thermoplastic elastomer composition having a polymer block (ii) content of 10 to 95% by mass.
(A1) The hydrogenation rate of double bonds derived from conjugated dienes is 80% or more.
(A2) The weight average molecular weight is 50,000 to 700,000.   The thermoplastic elastomer composition according to claim 1, further comprising 0.05 to 5 parts by mass of (D) a surface treatment agent with respect to 100 parts by mass of the (C) thermally conductive filler.   The thermoplastic elastomer composition according to claim 1 or 2, wherein a blending amount of the (B) liquid component is 20 to 500 parts by mass with respect to 100 parts by mass of the (A) hydrogenated diene copolymer.   The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the liquid component (B) includes the softening agent and the liquid polymer.   The thermoplastic elastomer composition according to claim 4, wherein the liquid polymer is liquid polybutene.   The thermoplastic elastomer composition according to any one of claims 2 to 5, wherein the (D) surface treatment agent is a saturated fatty acid.   The heat conductive sheet which consists of a thermoplastic elastomer composition as described in any one of Claims 1-6.   The heat conductive sheet according to claim 7 whose thickness is 0.1-3 mm.