JP5941287B2 - Heat dissipation sheet and manufacturing method thereof - Google Patents

Description

  The present invention relates to a heat radiating sheet interposed between a heat generating element such as a heat generating electronic component and a heat radiating cooler such as a heat sink, and a method for manufacturing the same.

In recent years, electronic devices such as flat-screen TVs, personal computers, digital cameras, and electroluminescence (LEDs) have been remarkably improved in performance, and a large number of heat-generating electronic components have been incorporated at a high density in an increasingly smaller mounting area. ing. Accordingly, there is a demand for a thin heat dissipation member and high thermal conductivity. Conventionally, as a heat conductive sheet used for a part of a heat radiation cooling structure such as a heat generating electronic component mounted on a substrate, the following low hardness type heat conductive sheet has been proposed.
(1) When pressed between the heat generating electronic component and the radiator, the compression load of the heat conductive sheet is kept low, thereby eliminating deformation and damage due to compression of the chip and the radiator.
(2) When the pressure contact surface is pressed between the heat-generating electronic component and the heat radiating member, the heat conductive sheet is softened to sufficiently adhere to ensure a heat transfer area.
(3) When a plurality of heat-generating electronic components with different heights mounted on a substrate and a heat-dissipating member are pressed against each other, the heat-conductive sheet is softened to make a plurality of different heights. It adheres well to all of the chips, and eliminates deformation and damage due to compression of the heat-generating electronic components and the radiator.

  Patent Documents 1 to 3 and the like are proposals for reducing the surface tackiness (adhesiveness) of a silicone rubber sheet containing a thermally conductive filler. If the surface tackiness (adhesiveness) is high, dust adhesion, failure due to adhesion on the parts feeder, repair failure, etc. are likely to occur. Patent Document 1 proposes that a silicone rubber curing agent is attached to the surface of a silicone rubber by a transfer method and is cured by heating, whereby only the surface layer of the silicone rubber is cured to a higher degree. Patent Documents 2 to 3 propose that a silicone layer having higher hardness is laminated on the surface layer of silicone rubber.

  However, Patent Document 1 has a problem that the curing agent transferred to the surface diffuses into the silicone rubber and hardens into the silicone rubber. In Patent Documents 2 and 3, since a plurality of layers of silicone rubber are laminated, there is a problem in that the thickness of the layers cannot be reduced as a whole.

Japanese Patent No. 3616630 JP 2005-161132 A JP 2007-099835 A

  In order to solve the above-described conventional problems, the present invention does not change the flexibility of the silicone rubber layer even if the thickness is reduced, and the heat dissipation sheet that can reduce the surface tackiness (adhesiveness) of the silicone rubber sheet and its A manufacturing method is provided.

The heat dissipating sheet of the present invention is a heat dissipating sheet in which the inner layer is a silicone rubber layer, and a non-adhesive layer is disposed on at least one surface of the silicone rubber layer, and the non-adhesive layer comprises a solvent -soluble resin. a thin film containing a range of less than the thickness Hiroyoshi 1μm or 10 [mu] m, characterized in that it reduces the surface tackiness of the inner silicone rubber layer.

The method for manufacturing a heat dissipation sheet according to the present invention is a method for manufacturing a heat dissipation sheet in which an inner layer is a silicone rubber layer, and at least one surface of the silicone rubber layer is provided with a non-adhesive layer, and the base film can be made of a solvent. Forming a thin film containing a melt-type resin, placing the thin film together with the base film toward at least one surface of the uncured silicone rubber layer, and in the case of single-sided arrangement, arranging a protective film on the other surface, Rolling by passing between a pair of rolls, and then heating to cure the uncured silicone rubber layer, the thin film is transferred to at least one surface of the silicone rubber layer, and the surface tackiness of the silicone rubber layer is increased. It is characterized by being reduced.

In the present invention, the non-adhesive layer of the heat dissipation sheet is formed by forming a thin film containing a solvent -soluble resin by a transfer method, so that the flexibility of the silicone rubber sheet is not changed even if the thickness of the silicone rubber layer is reduced. Surface tackiness (adhesiveness) can be reduced. That is, the tackiness (adhesiveness) can be reduced only on the surface independently without affecting the hardness and other physical properties of the silicone rubber layer. As a result, it is possible to improve dust adhesion, failure due to adhesion in the parts feeder, repair failure, and the like. The method of the present invention can efficiently produce the heat-dissipating sheet of the present invention by forming a resin thin film layer on an uncured silicone rubber layer by a transfer method, rolling with a roll, and heat-curing.

1A to 1F are schematic cross-sectional views showing a manufacturing process of a heat dissipation sheet in one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a heat-dissipating sheet with a reinforcing layer in another embodiment of the present invention.

(1) Non-adhesive layer In the present invention, the thin film containing a solvent -soluble resin that is a non-adhesive layer is a polyester resin, an acrylic resin, a melamine resin, a phenol resin, a urea resin, a polyurethane resin, or cellulose. Resin, styrene-maleic acid resin, styrene-acrylic resin, chlorinated polyolefin resin, vinyl chloride resin, and the like can be used. Of these, polyester resins are preferred because of their good thin film forming properties.

  A thermosetting resin can be used as the polyester resin. Thermoplastic polyester resins include dibasic acids such as terephthalic acid, isophthalic acid, adipic acid, and sebacic acid, glycols such as ethylene glycol, 1,3-trimethylene glycol, and 1,4-tetramethylene glycol, and trimesic acid. It is obtained by esterification and polycondensation reaction of polyfunctional components such as glycerin. Another example is L-lactide, DL-lactide, caprolactone, polyglycerin having a degree of polymerization of about 2 to 20 and tin octylate as a ring-opening polymerization catalyst, followed by heat-opening reaction, It can be obtained by polycondensation under reduced pressure. These polyester resins are dissolved in a solvent such as ethyl acetate, toluene, methyl ethyl ketone (MEK), coated on a base film, and dried.

  As the base film, a polyethylene terephthalate (PET) film, a polypropylene (PP) film, or the like can be used. Examples of the coating method on the base film include a general coating method using a coating machine such as a reverse roll coater, a gravure coater, a micro gravure coater, a comma coater, a bar coater, and an air doctor coater.

  The thickness of the non-adhesive layer is preferably in the range of 1 μm or more and less than 10 μm. If it is the thickness of this range, the preferable surface tack property can be provided, without impairing the softness | flexibility of an internal thin cone rubber layer.

  A release layer may be formed before the non-adhesive layer is formed on the base film. The release layer includes, for example, plant waxes such as carnauba wax, caster wax, canderia wax, and montan wax, animal waxes such as beeswax, hydrocarbon waxes such as natural paraffin, fatty acid waxes such as stearic acid, stearic acid Fatty acid amide waxes such as amide, palmitic acid amide, methylene bisstearamide, ethylene bisstearamide, oleic acid amide, esylic acid amide, fatty acid lower alcohol ester, fatty acid polyhydric alcohol ester, fatty acid polyglycol ester, etc. Ester waxes, higher alcohol waxes such as cetyl alcohol and stearyl alcohol, and metal soaps derived from fatty acids having 12 to 30 carbon atoms. The thickness of the release layer is preferably 0.01 μm to 2.0 μm, more preferably 0.1 to 1.0 μm. The release layer can also be formed by the same method as the non-adhesive layer.

(2) Silicone rubber raw material It is preferable to use the following raw materials for the silicone rubber layer.
(a) Organopolysiloxane containing an alkenyl group bonded to two or more silicon atoms on average in one molecule: 100 parts by mass
(b) Organopolysiloxane containing hydrogen atoms bonded to two or more silicon atoms on average in one molecule: 0 moles of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups in component (a) .1 to 10 mol
(c) Platinum-based metal catalyst: an amount that is 0.01 to 1000 ppm by mass with respect to component (a)
(d) Thermally conductive particles: 100 to 3000 parts by mass with respect to 100 parts by mass of the silicone rubber component
(e) An alkyltrialkoxysilane may be further added to the silicone rubber component.

(A) Alkenyl group-containing organopolysiloxane The component (a) of the present invention is an organopolysiloxane containing two or more alkenyl groups bonded to silicon atoms in one molecule, and an organopolysiloxane containing two alkenyl groups. Siloxane is the main agent (base polymer component) in the silicone rubber composition of the present invention. This organopolysiloxane has, as an alkenyl group, two alkenyl groups bonded to a silicon atom having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, such as vinyl group and allyl group, in one molecule. The viscosity is preferably 10 to 100000 mPa · s, particularly 100 to 100000 mPa · s at 25 ° C. from the viewpoint of workability and curability.

  Specifically, the main chain having one alkenyl group on each silicon atom at both ends of the molecular chain represented by the following general formula (Formula 1) is composed of repeating diorganosiloxane units having no alkenyl group. A linear organopolysiloxane having both molecular chain ends blocked with a triorganosiloxy group and having a viscosity of 10 to 100000 mPa · s at 25 ° C. is preferable from the viewpoint of workability and curability. The linear organopolysiloxane may contain a small amount of a branched structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group not having the same or different aliphatic unsaturated bond, R ² is an alkenyl group, and k is 0 or a positive integer.

Here, as the unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond of R ¹ , for example, those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms are preferable, specifically Alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, phenyl Group, tolyl group, xylyl group, aryl group such as naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, and part or all of hydrogen atoms of these groups are fluorine, bromine, chlorine, etc. Substituted with a halogen atom, a cyano group, etc., such as a halogen atom such as chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group, etc. Alkyl group, cyanoethyl group and the like. As the alkenyl group for R ² , for example, an alkenyl group having 2 to 6 carbon atoms, particularly 2 to 3 carbon atoms is preferable, and specifically, a vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, hexenyl group. And a cyclohexenyl group, and a vinyl group is preferable.

  In general formula (1), k is generally 0 or a positive integer that satisfies 0 ≦ k ≦ 10000, preferably 5 ≦ k ≦ 2000, more preferably 10 ≦ k ≦ 1200. It is.

  As the organopolysiloxane of component (a), for example, 3 or more alkenyl groups bonded to silicon atoms having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms such as vinyl groups and allyl groups in one molecule, usually 3 to You may use together the organopolysiloxane which has 30 pieces, Preferably about 3-20 pieces. The molecular structure may be any of linear, cyclic, branched, and three-dimensional network structures. Preferably, the main chain is composed of repeating diorganosiloxane units, both ends of the molecular chain are blocked with triorganosiloxy groups, and the viscosity at 25 ° C. is 10 to 100000 mPa · s, particularly 100 to 100,000 mPa · s. An organopolysiloxane.

  Even if the alkenyl group is bonded to the silicon atom at the end of the molecular chain or bonded to the silicon atom at the non-end of the molecular chain (in the middle of the molecular chain), both types of alkenyl groups are mixed in one molecule. May be. Among them, each having 1 to 3 alkenyl groups on the silicon atoms at both ends of the molecular chain represented by the following general formula (Chemical Formula 2) (provided that the alkenyl group bonded to the silicon atom at the molecular chain end is When the total number of both ends is less than 3, the alkenyl group bonded to the silicon atom at the non-end of the molecular chain (in the middle of the molecular chain) (for example, as a substituent in the diorganosiloxane unit) has at least one As described above, a linear organopolysiloxane having a viscosity of 10 to 1,000,000 mPa · s at 25 ° C. is desirable from the viewpoint of workability, curability, etc. Note that this linear organopolysiloxane has a small amount of branching. It may also contain a structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and at least one is an alkenyl group. R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group which does not have the same or different aliphatic unsaturated bond, R ⁵ is an alkenyl group, and l and m are 0 or a positive integer.

Here, as the monovalent hydrocarbon group of R ³ , those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms are preferable, and specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, Alkyl group such as isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, benzyl Group, aralkyl group such as phenylethyl group, phenylpropyl group, etc., alkenyl group such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, and hydrogen of these groups Some or all of the atoms are substituted with halogen atoms such as fluorine, bromine and chlorine, cyano groups, etc., for example, chloromethyl , Chloropropyl group, bromoethyl group, and a halogen-substituted alkyl group or cyanoethyl group such trifluoropropyl group.

Also, as the monovalent hydrocarbon group for R ⁴ , those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms are preferable, and the same examples as the specific examples of R ¹ can be exemplified, but an alkenyl group is not included. .

As the alkenyl group for R ⁵ , for example, those having 2 to 6 carbon atoms, particularly those having 2 to 3 carbon atoms are preferable, and specifically the same as R ^{2 in the} above formula (Chemical Formula 1) are exemplified, preferably vinyl group It is.

l and m are generally 0 or a positive integer satisfying 0 <l + m ≦ 10000, preferably 5 ≦ l + m ≦ 2000, more preferably 10 ≦ l + m ≦ 1200, and 0 <l / (l + m ) ≦ 0.2, preferably an integer satisfying 0.0011 ≦ l / (l + m) ≦ 0.1.

(B) Organohydrogenpolysiloxane The organohydrogenpolysiloxane of component (b) of the present invention acts as a cross-linking agent, and the SiH group in this component and the alkenyl group in component (a) undergo an addition reaction. A cured product is formed by (hydrosilylation). The organohydrogenpolysiloxane may be any organohydrogenpolysiloxane as long as it has two or more hydrogen atoms (that is, SiH groups) bonded to silicon atoms in one molecule. Any of linear, cyclic, branched, and three-dimensional network structures may be used, but the number of silicon atoms in one molecule (that is, the degree of polymerization) is about 2 to 1000, particularly about 2 to 300. Can be used.

The position of the silicon atom to which the hydrogen atom is bonded is not particularly limited, and may be at the end of the molecular chain or at the non-terminal (midway). The organic groups bonded to silicon atoms other than hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group that does not have the same aliphatic unsaturation and R ¹ in the general formula (Formula 1) .

  Examples of the organohydrogenpolysiloxane of component (b) include hydrogenorganosiloxanes having the following structure.

  In the above formula, Ph is an organic group containing at least one of a phenyl group, an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxy group. L is an integer of 0 to 1,000, particularly an integer of 0 to 300, and M is an integer of 1 to 200. )

Such an organohydrogenpolysiloxane can be obtained by a known method, for example, R ⁵ SiHCl ₂ , (R ⁵ ) ₃ SiCl, (R ⁵ ) ₂ SiCl ₂ , (R ⁵ ) ₂ SiHCl (wherein R ⁵ is A chlorosilane such as a methyl group, an alkyl group such as an ethyl group, or an aryl group such as a phenyl group, or by equilibrating a siloxane obtained by hydrolysis.

(C) Platinum group metal-based catalyst The platinum group metal-based catalyst of component (c) of the present invention is blended to cause an addition curing reaction in the composition of the present invention, and is a so-called hydrosilylation catalyst. Any of those known as can be used. Examples of the catalyst include platinum-based, palladium-based, and rhodium-based catalysts. From the viewpoint of cost and the like, platinum-based catalysts such as platinum, platinum black, and chloroplatinic acid such as H ₂ PtCl ₆ · mH ₂ O, Platinum compounds such as K ₂ PtCl ₆ , KHPtCl ₆ · mH ₂ O, K ₂ PtCl ₄ , K ₂ PtCl ₄ · mH ₂ O, PtO ₂ · mH ₂ O (m is a positive integer), and these platinum compounds Examples thereof include hydrocarbons such as olefins, alcohols, and complexes with vinyl group-containing organopolysiloxanes. These can be used alone or in combination of two or more.

(D) Thermally conductive particles The component (d) of the present invention is preferably added in an amount of 100 to 3000 parts by mass with respect to 100 parts by mass of the silicone rubber layer. Thereby, the heat conductivity of a thermal radiation sheet can be made into the range of 0.3-20 W / mK. The heat conductive particles are preferably at least one selected from alumina, zinc oxide, magnesium oxide and silica. Various shapes such as a spherical shape, a scale shape, and a polyhedral shape can be used. The specific surface area of the heat conductive particles is preferably in the range of 0.06 to ²⁰ m ² / g. The specific surface area is a BET specific surface area, and the measuring method is in accordance with JIS R1626. When using an average particle diameter, the range of 0.1-50 micrometers is preferable. The particle diameter is measured by 50% particle diameter by a laser diffraction light scattering method. An example of this measuring instrument is a laser diffraction / scattering particle distribution measuring apparatus LA-950S2 manufactured by Horiba.

The thermally conductive inorganic powder is R (CH ₃ ) _a Si (OR ′) _3-a (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a May be surface-treated with 0 or 1) silane, or a partial hydrolyzate thereof. R (CH ₃ ) _a Si (OR ′) _3-a (wherein R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) Examples of silane compounds (hereinafter simply referred to as “silane”) include hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, and dodecyltrimethoxysilane. , Dodecyltriethoxysilane, hexadodecyltrimethoxysilane, hexadodecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane. The said silane compound can be used 1 type or in mixture of 2 or more types. Surface treatment here includes adsorption in addition to covalent bonds.

(e) Other components Components other than the components (a) to (d) can be blended in the composition of the present invention as necessary. For example, an inorganic trial pigment such as Bengala, an alkyltrialkoxysilane or the like may be added for the purpose of surface treatment of the filler.

(3) Sheet molding of silicone rubber raw material The above components (a) to (d), and optionally (e) component, are added and mixed to form an uncured silicone rubber compound and molded into a sheet. Sheet molding is performed by rolling between two protective films. For example, a PET film or a PP film is used as the protective film. After the uncured silicone rubber sheet is formed, one sheet is rolled using a base film on which the non-adhesive layer is formed, and the other sheet is rolled using a protective film such as a PET film or a PP film. Thereby, a silicone rubber having a non-adhesive surface is obtained. In order to make both surfaces non-adhesive, both are rolled using the base film on which the non-adhesive layer is formed. At this time, the non-adhesive layer is disposed toward the uncured silicone rubber compound surface. Rolling is performed by passing between at least a pair of rolls.

  When a reinforcing layer is to be inserted, it is inserted during molding of the uncured silicone rubber compound sheet. The reinforcing layer is embedded on the one-side surface layer portion of the ricone rubber layer and below the non-adhesive layer. The reinforcing layer can be a sheet or a mesh. For example, a network structure, a net, a fabric, or the like using at least one fiber selected from synthetic fibers and natural fibers is preferable. Synthetic fibers include polyester fibers, heat resistant nylon fibers, aramid fibers, polyolefin fibers, vinylon fibers, and the like, and natural fibers such as cotton and hemp fibers can be used.

(4) Curing of silicone rubber sheet Thereafter, the uncured silicone rubber layer is cured by heating. Thereby, the said non-adhesion layer is transcribe | transferred to at least one surface of a silicone rubber layer, and the surface tack property of a silicone rubber layer is reduced. The heating temperature for curing is preferably 20 to 150 ° C., and the heating and curing time is preferably in the range of 5 to 120 minutes. In this way, a heat dissipation sheet is obtained. The preferable thickness of the heat dissipation sheet is in the range of 0.1 to 10 mm, and more preferably in the range of 0.5 to 5 mm.

  Next, it demonstrates using drawing. 1A to 1D are schematic cross-sectional views showing a manufacturing process of a heat dissipation sheet in one embodiment of the present invention. FIG. 1A shows a transfer sheet 4 in which a release layer 2 and a non-adhesive layer 3 are formed in this order on the surface of a base film 1. FIG. 1B shows a state where an uncured silicone rubber layer 6 is formed on the surface of the protective film 5 and the transfer sheet 4 is pressed with the non-adhesive layer 3 facing the surface of the uncured silicone rubber layer 6. FIG. 1C shows a state where the silicone rubber layer 6 is cured by roll-pressing the transfer sheet 4 on the surface of the silicone rubber layer 6 and then performing heat treatment. The non-adhesive layer 3 is transferred to the silicone rubber layer 6. The thermally conductive silicone rubber product may be in this state, and the protective film 5 and / or the base film 1 may be replaced. FIG. 1D shows a state where the protective film 5 and the base film 1 are peeled off. 7a is a heat dissipation sheet. In this state, a protective sheet can be attached to both sides to make a product. FIG. 1E shows a state in which the transfer sheet 4 is disposed on the upper and lower surfaces of the silicone rubber layer 6 and the protective film 5 is peeled off. The release layer 2 may be removed together with the base film, or may remain in the non-adhesive layer 3. 7b is a heat dissipation sheet. In this state, a protective sheet can be attached to both sides to make a product.

  FIG. 2 is a schematic cross-sectional view of a heat-dissipating sheet with a reinforcing layer in another embodiment of the present invention. This is an example in which a sheet-like or mesh-like reinforcing layer 8 is embedded under the non-adhesive layer 3 on the one-side surface layer portion of the silicone rubber layer 6. 9 is a heat dissipation sheet with a reinforcing layer.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to the following Example.

<Measurement method>
(1) Thermal conductivity: It measured using the hot disk method (Kyoto Electronics Industrial Co., Ltd.) thermophysical property measuring apparatus TPA-501 (product name). The measurement sample was prepared as follows. The sheet was cut into a size of 25 mm in length × 25 mm in width, and four of them were overlapped to form one block. Two of these were prepared. A sensor having a diameter of 7 mm was sandwiched between prepared blocks and set on a jig. The torque between the jigs was 30 N · cm. A sheet without self-adhesiveness was also stacked to form one block. As for the measurement method, the cover attached to the jig was covered so as not to be exposed to wind when set on the jig, stabilized for 15 minutes, and then measured.
(2) Rubber hardness: According to JIS K 7312.
(3) Surface tackiness: A 50 mm × 100 mm sample is bonded to the surface of a 40 mm × 100 mm solder glass, and a 1 kg weight is placed on it and left for 1 minute. After leaving, the glass plate is placed on a fixed table having a height of 130 mm or more with the surface to which the sample is attached facing down, and the time until the sample falls is measured.
(4) Compressive load: Measured using a desktop load measuring instrument (Iko Engineering Co., Ltd.) MODEL-1310NW (product name) and load cell CAPACITY 200 kgf. The measurement sample was prepared as follows. Cut a sheet with a thickness of 1.0 mm into a size 25 mm long x 25 mm wide, sandwiched between two aluminum plates (surface anodized) 27 mm long x 27 mm wide x 4 mm thick, set in a measuring instrument, and compressed by 0.2 mm did.
(5) Tensile strength, elongation: JIS K 6251 (No. 2) / ASTM D 412
(6) Tear strength: JIS K 6252 (angle) / ASTM D 624

Example 1
<Non-adhesive layer>
700 parts by mass of L-lactide, 300 parts by mass of DL-lactide, 10 parts by mass of polyglycerol having a polymerization degree of 10 (Daicel Chemical Industries, PGL: hydroxyl group concentration 850 KOHmg / g), aluminum acetylacetonate 1 as a ring-opening polymerization catalyst A ring opening reaction and an esterification reaction were carried out by charging a mass part into a four-necked flask and heating and melting at 180 ° C. for 3 hours in a nitrogen atmosphere. Thereafter, residual lactide was distilled off under reduced pressure, and a polycondensation reaction was performed to obtain a polyester resin. The obtained polyester resin had a reduced viscosity of 0.55 dl / g, a hydroxyl group concentration of 150 eq / 10 ⁶ g, and a glass transition temperature of 48 ° C.

  A 1% by mass solution of carnauba wax dissolved in toluene was applied on one side of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm with a gravure coater to form a release layer having a dry thickness of 0.1 μm. Next, the polyester resin was dissolved in 50% by mass of methyl ethyl ketone (MEK) / 50% by mass of toluene. The concentration of the polyester resin was 20% by mass. This solution was applied onto the release layer with a gravure coater and coated to a dry thickness of 3.0 μm to form a non-adhesive layer shown in FIG. 1A.

<Uncured silicone rubber compound>
As the silicone component, CF5036 (manufactured by Toray Dow Corning Silicone) “CF5036” was used as the two-component room temperature curing silicone rubber (two-component RTV). “CF5036” is pre-added with the components (a) to (c) of the present invention. As a component (d) (thermally conductive particles), 450 parts by mass of alumina with respect to 100 parts by mass of the silicone rubber layer and 10 parts by mass of aluminum hydroxide with respect to 100 parts by mass of the silicone rubber layer were mixed to obtain a compound.

<Silicone rubber molding and curing>
The compound was poured into a PET protective film that had been subjected to a fluorine release treatment, sandwiched by another film having the non-adhesive layer formed thereon, and rolled with a roll to form an uncured silicone rubber sheet having a thickness of 1 to 3 mm. At this time, the non-adhesive layer was disposed toward the uncured silicone rubber layer. Next, a metal frame is placed on a PET protective film that has been subjected to a fluorine release treatment, the compound is poured into the film, sandwiched by another film having the non-adhesive layer formed thereon, rolled with a roll, and uncured silicone having a thickness of 1 to 3 mm. A rubber sheet was formed. At this time, the non-adhesive layer was disposed toward the uncured silicone rubber layer. Next, it was cured at 100 to 120 ° C. for 3 to 10 minutes. Thereby, a silicone rubber sheet having a thickness of 1 to 3 mm was formed.

The resulting silicone rubber sheet has a thermal conductivity of 1.5 W / m · K, a rubber hardness of ASKER-C 32, a surface tack of 1 second or less, a compressive load of 52 N / cm ² , a tensile strength of 0.3 MPa, and a tear strength. 1kN / m, elongation was 100%.

(Example 2)
<Non-adhesive layer>
240 parts by mass of L-lactide, 240 parts by mass of DL-lactide, 320 parts by mass of caprolactone, 8 parts by mass of polyglycerol having a polymerization degree of 10 (Daicel Chemical Industries, PGL: hydroxyl group concentration 850 KOHmg / g), ring-opening polymerization catalyst As described above, 0.1 part by mass of tin octylate was added to a four-necked flask and heated at 180 ° C. for 3 hours in a nitrogen atmosphere to perform a ring-opening reaction and an esterification reaction. Thereafter, residual lactide was distilled off under reduced pressure, and a polycondensation reaction was performed to obtain a polyester resin. The obtained polyester resin had a reduced viscosity of 0.57 dl / g, a hydroxyl group concentration of 150 eq / 10 ⁶ g, and a glass transition temperature of -5 ° C. This polyester resin was used as the non-adhesive layer in the same manner as in Example 1.

Production of uncured silicone rubber compound and molding / curing of silicone rubber were carried out in the same manner as in Example 1. The obtained silicone rubber sheet has a thermal conductivity of 1.5 W / m · K, a rubber hardness of ASKER-C 32, a surface tack of 1 second or less, a compressive load of 52 N / cm ² , a tensile strength of 0.3 MPa, and tearing. The strength was 1 kN / m and the elongation was 100%.

(Comparative Example 1)
In Example 1, it experimented similarly except not having arrange | positioned the non-adhesion layer. The resulting silicone rubber sheet has a thermal conductivity of 1.5 W / m · K, a rubber hardness of ASKER-C 28, a surface tack of 75 seconds, a compressive load of 54 N / cm ² , a tensile strength of 0.3 MPa, and a tear strength. The thickness was 1 kN / m and the elongation was 100 % .

(Comparative Example 2)
In Example 1, the non-adhesive layer is an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms in one molecule. RD-1 having a concentration of 10%: manufactured by Toray Dow Corning Silicone (experiment No. 1) and RD-1 having a concentration of 30%: The same experiment was conducted except that they were made by Toray Dow Corning Silicone (Experiment No. 2). The obtained silicone rubber sheet of Experiment No. 1 has a thermal conductivity of 1.5 W / m · K, a rubber hardness of ASKER-C 34, a surface tack of 5 seconds, a compressive load of 64 N / cm ² , and a tensile strength of 0. The tensile strength was 5 MPa, the tear strength was 1 kN / m, and the elongation was 80% . The thermal conductivity of the silicone rubber sheet of Experiment No. 2 is 1.5 W / m · K, the rubber hardness is ASKER-C 41, the surface tackiness is 1 second, the compressive load is 70 N / cm ² , the tensile strength is 0.7 MPa, and tearing The strength was 1 kN / m and the elongation was 70%.

(Example 3)
In Example 1, as shown in FIG. 2, a reinforcing layer made of a polyester mesh fabric was embedded under the non-adhesive layer on one side of the silicone rubber layer. This mesh fabric was named “Nylon Mesh # 3050” manufactured by Moon Techno Co., Ltd. The resulting silicone rubber sheet has a thermal conductivity of 1.5 / m · K, a rubber hardness of ASKER-C 51, a surface tack of 1 second or less, a compressive load of 85 N / cm ² , a tensile strength of 0.5 MPa, and tearing. The strength was 2 kN / m and the elongation was 60% . Compared to the product obtained in Example 1, the dimensional stability was high.

DESCRIPTION OF SYMBOLS 1 Base film 2 Release layer 3 Non-adhesion layer 4 Transfer sheet 5 Protective film 6 Silicone rubber layer 7a, 7b Heat radiation sheet 8 Reinforcement layer 9 Heat radiation sheet with a reinforcement layer

Claims (9)

The inner layer is a silicone rubber layer, and at least one surface of the silicone rubber layer is a heat dissipation sheet in which a non-adhesive layer is disposed,
The non-adhesive layer is a thin film containing a solvent-soluble resin is in the range of less than the thickness Hiroyoshi 1μm or 10 [mu] m,
A heat dissipating sheet, wherein surface tackiness of the inner silicone rubber layer is reduced.   The non-adhesive layer is made of polyester resin, acrylic resin, melamine resin, phenol resin, urea resin, polyurethane resin, cellulose resin, styrene-maleic acid resin, styrene-acrylic resin, chlorinated polyolefin. The heat-radiating sheet according to claim 1, which is at least one selected from a resin and a vinyl acetate-based resin.   The heat radiation sheet according to claim 1 or 2, wherein the heat radiation sheet has a thickness in a range of 0.1 to 10 mm.   The heat dissipation sheet according to any one of claims 1 to 3, wherein 100 to 3000 parts by mass of thermally conductive particles are added to 100 parts by mass of the silicone rubber layer.   The heat dissipation sheet according to any one of claims 1 to 4, wherein the heat conductivity of the heat dissipation sheet is in a range of 0.3 to 20 W / mK.   The heat-radiating sheet according to any one of claims 1 to 5, wherein a sheet-like or mesh-like reinforcing layer is embedded under the non-adhesive layer on the one-side surface layer portion of the silicone rubber layer. The inner layer is a silicone rubber layer, and at least one surface of the silicone rubber layer is a method for manufacturing a heat dissipation sheet in which a non-adhesive layer is disposed,
A thin film containing a solvent-soluble resin is formed on the base film,
The base film is disposed with the thin film facing at least one surface of the uncured silicone rubber layer, and in the case of single-sided arrangement, a protective film is disposed on the other surface,
Rolling by passing between at least a pair of rolls, then heating to cure the uncured silicone rubber layer, transferring the thin film to at least one surface of the silicone rubber layer, surface tackiness of the silicone rubber layer The manufacturing method of the heat-radiation sheet according to any one of claims 1 to 6, wherein The method for manufacturing a heat dissipation sheet according to claim 7, wherein the uncured silicone rubber has the following composition.
(a) Organopolysiloxane containing an alkenyl group bonded to two or more silicon atoms on average in one molecule: 100 parts by mass
(b) Organopolysiloxane containing hydrogen atoms bonded to two or more silicon atoms on average in one molecule: 0 moles of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups in component (a) .1 to 10 mol
(c) Platinum-based metal catalyst: an amount that is 0.01 to 1000 ppm by mass with respect to component (a)
(d) Thermally conductive particles: 100 to 3000 parts by mass with respect to 100 parts by mass of the silicone rubber layer   The method for manufacturing a heat dissipation sheet according to claim 8, wherein the uncured silicone rubber further contains an alkyltrialkoxysilane.

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