JP6539234B2 - Composite sheet and method for manufacturing the same - Google Patents

Description

  The present invention relates to a composite sheet in which a layer including a reinforcing sheet and a thermally conductive silicone rubber sheet layer is laminated.

  A composite sheet obtained by bringing a silicone composition into contact with a substrate sheet and curing the silicone composition is known as a composite sheet of a silicone elastomer and a substrate sheet such as a plastic film or a metal sheet. For example, it is proposed in patent documents 1 to 3 that a base material such as a resin and a rubber are thermocompression-bonded by an adhesive composed of an alkoxysilane-containing triazine thiol compound. Patent Document 4 proposes performing corona discharge, ultraviolet irradiation or plasma treatment on the bonding surface of a resin and silicone rubber.

Japanese Patent Application Publication No. 2007-119752 JP 2007-329302 A Patent No. 5083926 JP, 2014-062224, A

  However, since the thermally conductive silicone rubber contains a large amount of thermally conductive filler, the amount of the silicone polymer phase is small, for example, 20% by volume or less, and the sheet surface after curing and forming has no smoothness. It was difficult to laminate and integrate with the sheet.

  In order to solve the above-mentioned conventional problems, the present invention provides a composite sheet which improves the smoothness of the thermally conductive silicone rubber surface and enhances the integrity with a substrate sheet such as a resin film.

The composite sheet of the present invention is a composite sheet in which a layer including a substrate sheet made of a polyimide film and a thermally conductive silicone rubber sheet layer is laminated and integrated, and the thermally conductive silicone rubber sheet layer The conductivity is 0.6 W / m · K or more, the laminated and integrated surface of the heat conductive silicone rubber sheet layer is made smooth by calendering, and the smooth surface is exposed to corona, plasma, ultraviolet light and electron beam irradiation. The substrate sheet and the thermally conductive silicone rubber sheet layer are laminated and integrated by covalent bonding, and at least one selected surface activation is performed, and the peeling portion of the laminated surface is in a state of cohesive failure. It is characterized by

  The method for producing a composite sheet according to the present invention is a method for producing the composite sheet, wherein a thermally conductive silicone rubber sheet having a thermal conductivity of 0.6 W / m · K or more is calendered to smooth at least the lamination surface. The smooth surface is subjected to at least one surface activation treatment selected from corona treatment, plasma treatment, ultraviolet irradiation treatment and electron beam treatment, and the laminated surface of the substrate sheet contains nitrogen (N) and silicon (Si) A compound is coated, and at least one base sheet selected from a resin sheet and a metal sheet and the thermally conductive silicone rubber sheet layer are pressure-bonded and integrally laminated.

  In the composite sheet of the present invention, at least the lamination surface of the heat conductive silicone rubber sheet is smooth and surface activated, and the lamination surface of the substrate sheet is coated with a compound containing nitrogen (N) and silicon (Si) By pressure bonding the two, the thermally conductive silicone rubber sheet and the base sheet can be integrated by covalent bonding, and the peeling portion of the laminated surface can be made into a composite sheet having a strong integrated structure that causes cohesive failure.

FIG. 1A is a perspective view of a composite sheet according to an embodiment of the present invention, and FIG. 1B is an enlarged cross-sectional view taken along the line II of FIG. 1A. FIG. 2A is a cross-sectional view showing the smoothing process of the thermally conductive silicone rubber sheet by calendering, and FIG. 2B is a cross-sectional view of the thermally conductive silicone rubber sheet after calendering. FIGS. 3A to 3E are explanatory views of the surface treatment of the polyimide film by the bar coater. FIGS. 4A to 4D are explanatory views of pressure bonding of the thermally conductive silicone rubber sheet after the smoothing treatment by calendering and the surface activation treatment by corona treatment, and the polyimide film after the surface treatment. FIG. 5 is a graph showing the A-TES concentration and adhesion in the coating solution of one embodiment of the present invention. FIG. 6 is a graph showing adhesion time and adhesion of one embodiment of the present invention.

  The present invention is a composite sheet in which a layer including at least one base sheet selected from a resin sheet and a metal sheet, and a thermally conductive silicone rubber sheet layer is laminated and integrated. The heat conductive silicone rubber sheet layer may contain a reinforcing layer such as a fabric layer. The thermal conductivity of the thermally conductive silicone rubber sheet layer is 0.6 W / m · K or more. As an example, it is possible to make the silicone polymer 20 volume% or less and the thermally conductive particles 80 volume% or less. The thermally conductive silicone rubber sheet of the present invention comprises a gel-like thermally conductive silicone rubber sheet.

  The base sheet and the thermally conductive silicone rubber sheet layer are integrally laminated by covalent bonding. The covalent bond is preferably a covalent bond by a compound containing nitrogen (N) and silicon (Si). More preferably, the compound containing nitrogen (N) and silicon (Si) is a compound containing an alkoxysilyl group and an amino group or an azide group. The amino group or azide group tends to be covalently bonded to the base sheet, and the alkoxysilyl group easily bonds to the thermally conductive silicone rubber sheet.

  The peeling portion of the laminated surface is a strong integrated structure that causes cohesive failure. It is preferable that the cohesive failure of the laminated surface occurs on the heat conductive silicone rubber sheet layer side. The silicone polymer phase of the heat conductive silicone rubber sheet layer is small, and this portion is prone to cohesive failure. This cohesive failure includes those which cohesively break in a thin film.

  The covalent bond between the substrate sheet and the thermally conductive silicone rubber sheet layer is preferably in the state of single-molecule adhesion or multi-molecule adhesion. Such a state can be obtained by dissolving or dispersing adhesion molecules in a dilute solution and coating in a thin film state. By coating the adhesion molecules in a thin film state, when the laminated surface is peeled off, a strong integrated structure that can cause cohesive failure can be obtained.

  The resin sheet is preferably a polyimide film. The polyimide film tends to be covalently bonded to the amino group or azide group of the adhesion molecule.

  In the method of producing the composite sheet of the present invention, a thermally conductive silicone rubber sheet having a thermal conductivity of 0.6 W / m · K or more is calendered to have at least a laminated surface as a smooth surface. Then, the smooth surface is subjected to at least one surface activation treatment selected from corona treatment, plasma treatment, ultraviolet radiation treatment and electron beam treatment. Next, a compound surface containing nitrogen (N) and silicon (Si) is coated on the laminated surface of the base sheet to integrally integrate the base sheet and the thermally conductive silicone rubber sheet layer. Thereby, a strong laminated integrated structure with the substrate sheet is obtained.

The smooth surface of the heat conductive silicone rubber sheet layer preferably has an arithmetic average roughness Ra of 3 μm or less, and more preferably 2 μm or less. When the arithmetic average roughness Ra is 2 μm or less, it becomes a smooth surface having gloss. The smoother, the stronger the integration.

The compound containing nitrogen (N) and silicon (Si) is preferably a compound containing an alkoxysilyl group and an amino group or an azide group. The amino group or azide group tends to be covalently bonded to the base sheet, and the alkoxysilyl group easily bonds to the thermally conductive silicone rubber sheet. For example, in the case of a compound of Si (OR) ₃ -A-NH ₂ (where R is a methyl group, an ethyl group, a propyl group, and A is any organic group), the thermally conductive silicone rubber sheet -O-Si (OR ₂ ) Covalently bond in the form of a _2- A-NH-substrate sheet.

The compound containing nitrogen (N) and silicon (Si) is preferably diluted and coated with at least one diluent selected from water and an organic solvent. The concentration of the compound in the diluent is preferably 0.005% by mass or more. More preferably, it is 0.05-1 mass%. The coating amount per unit area of the compound is preferably 0.0011 g / m ² or more, more preferably 0.0011 to 0.2275 g / m ² , in dry mass. As the organic solvent, ethanol or ethanol-water mixed solution is preferable.

The lamination and integration of the base sheet and the thermally conductive silicone rubber sheet layer is preferably performed by at least one pressure selected from roll pressure and plate pressure. Plate pressurization is suitable for small volume production, and roll pressurization is suitable for mass production. The following conditions are preferable for lamination integration of a base material sheet and a heat conductive silicone rubber sheet layer.
(a) Pressure: 0.01 to 0.1 MPa is preferable, and more preferably 0.02 to 0.09 MPa.
(b) Temperature: 40-130 degreeC is preferable, More preferably, it is 45-125 degreeC.
(c) time: preferably 0.2 to 10 hours, more preferably 0.5 to 5 hours.

The silicone polymer which is the main component of the heat conductive silicone rubber sheet is generally linear polydiorganosiloxacin. The linear polydiorganosiloxane is composed of diorganosiloxane units, and the end of the polymer is blocked with a hydroxyl group, a hydrogen atom, a monovalent organic group, or a silyl group having a hydrolyzable group such as trimethoxysilyl group. ing. It is also possible to use branched polysiloxanes which also contain monoorganosiloxane units in part. As a silicone polymer which is a main component of the composition for a substrate, a network-like polysiloxane composed of a triorganosiloxane unit, a diorganosiloxane unit, a monoorganosiloxane unit, and a SiO ₂ unit, and a resinous polysiloxane are used. You can also.

  As the organic group of such silicone polymer, an alkyl group such as methyl group, an aryl group such as phenyl group, a substituted alkyl group such as 1,1,1-trifluoropropyl group, an alkenyl group such as vinyl group, etc. are used . In particular, most of the organic groups are generally methyl groups. An appropriate amount of an alkenyl group such as a vinyl group is used to control peroxide curing or addition curing by a hydrosilylation reaction. In the case of forming a substrate having a high refractive index or a substrate capable of maintaining a rubbery state at low temperature, a phenyl group is used. In order to lower surface tension and improve oil resistance, 1,1,1-trifluoropropyl group is used.

When the matrix resin is an organopolysiloxane, a compound having the following composition is obtained by curing, as an example.
(A) Base polymer component: linear organopolysiloxane having an average of 2 or more per molecule and an alkenyl group bonded to a silicon atom at both ends of the molecular chain (B) Crosslinking component: 2 in average per molecule The amount of organohydrogenpolysiloxane containing hydrogen atoms bonded to the above silicon atoms is less than 1 mole relative to 1 mole of silicon-bonded alkenyl groups in the component A (C) Platinum-based metal catalyst: Component A Against 0.01 to 1000 ppm by weight
(D) thermally conductive particles: 100 to 2000 parts by weight with respect to 100 parts by weight of matrix resin (E) other components

(1) Base polymer component (A component)
The base polymer component (component A) is an organopolysiloxane containing two or more alkenyl groups bonded to a silicon atom in one molecule, and an organopolysiloxane containing two alkenyl groups is the silicone rubber composition of the present invention Main component (base polymer component) in This organopolysiloxane has, as alkenyl groups, two alkenyl groups each having 2 to 8 carbon atoms, particularly 2 to 6 carbon atoms, such as a vinyl group or allyl group, bonded to a silicon atom in one molecule. It is desirable from the viewpoint of workability, curability, etc. that the viscosity is 10 to 1,000,000 mPa · s, particularly 100 to 100,000 mPa · s at 25 ° C.

  Specifically, an organopolysiloxane having an average of 2 or more and an alkenyl group bonded to a silicon atom at the end of a molecular chain in one molecule represented by the following general formula (Formula 1) is used. The side chains are linear organopolysiloxanes blocked with triorganosiloxy groups. The viscosity at 25 ° C. is preferably 10 to 1,000,000 mPa · s from the viewpoint of workability and curability. In addition, this linear organopolysiloxane may contain a small amount of branched structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having no identical 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, one having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms is preferable, and specifically, Alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl and decyl; Group, aryl groups such as tolyl group, xylyl group and naphthyl group, aralkyl groups such as benzyl group, phenylethyl group and phenylpropyl group, and part or all of hydrogen atoms of these groups are fluorine, bromine, chlorine, etc. Substituted by a halogen atom or cyano group, for example, a halogen such as chloromethyl group, chloropropyl group, bromoethyl group or trifluoropropyl group Alkyl group, cyanoethyl group and the like. The alkenyl group represented by R ² is, for example, preferably one having 2 to 6 carbon atoms, and more preferably 2 to 3 carbon atoms, and specifically vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl and hexenyl groups. And a cyclohexenyl group etc., preferably a vinyl group. In the general formula (1), k is generally 0 or a positive integer satisfying 0 ≦ k ≦ 10,000, preferably an integer satisfying 5 ≦ k ≦ 2000, more preferably 10 ≦ k ≦ 1200. It is.

  As the organopolysiloxane of the component A, for example, 3 or more, usually 3 to 30 alkenyl groups bonded to silicon atoms having 2 to 8 carbon atoms, especially 2 to 6 carbon atoms, such as vinyl and allyl groups, in one molecule Preferably, organopolysiloxane having about 3 to 20 may be used in combination. The molecular structure may be linear, cyclic, branched or three-dimensional network molecular structure. Preferably, the main chain is a repeat of diorganosiloxane units, and both ends of the molecular chain are blocked with a triorganosiloxy group, and a linear chain having a viscosity of 10 to 1000000 mPa · s, particularly 100 to 100000 mPa · s at 25 ° C. -Like organopolysiloxane.

The alkenyl group may be attached to any part of the molecule. For example, it may include one bound to a silicon atom at the end of a molecular chain or at the end of a molecular chain (in the middle of a molecular chain). Among them, one to three alkenyl groups are provided on the silicon atoms at both ends of the molecular chain represented by the following general formula (Formula 2) (however, the alkenyl group bonded to the silicon atom at the molecular chain ends is If it is less than 3 at both ends total, an alkenyl group bonded to a silicon atom at a molecular chain non-end (along the molecular chain), are closed at least one (as a substituent in the example diorganosiloxane units)) A linear organopolysiloxane having a viscosity of 10 to 1,000,000 mPa · s at 25 ° C. as described above is desirable from the viewpoint of workability and curability. In addition, this linear organopolysiloxane may contain a small amount of branched structure (trifunctional siloxane unit) in the molecular chain.

In the formula, R ³ is an identical 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 having no aliphatic unsaturated bond which is the same as or different from one another, R ⁵ is an alkenyl group, and l and m are 0 or a positive integer. Here, as the monovalent hydrocarbon group for 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 and decyl group, aryl group such as phenyl group, tolyl group, xylyl group and naphthyl group, benzyl Groups, aralkyl groups such as phenylethyl group and phenylpropyl group, vinyl groups, allyl groups, propenyl groups, isopropenyl groups, butenyl groups, butenyl groups, hexenyl groups, alkenyl groups such as cyclohexenyl groups and octenyl groups, and hydrogens of these groups Some or all of the atoms are substituted with a halogen atom such as fluorine, bromine or chlorine, a cyano group or the like, 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 ones as the specific examples of R ¹ can be exemplified, but the alkenyl group is not included . The alkenyl group represented by R ⁵ is preferably, for example, one having 2 to 6 carbon atoms, and more preferably 2 to 3 carbon atoms, and specific examples thereof include the same as R ^{2 in the} above formula (Formula 1). 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 And so forth), preferably 0.0011 ≦ l / (l + m) ≦ 0.1.

(2) Crosslinking component (component B)
The organohydrogenpolysiloxane of component B of the present invention acts as a crosslinking agent, and forms a cured product by the addition reaction (hydrosilylation) between the SiH group in this component and the alkenyl group in component A. It is a thing. The organohydrogenpolysiloxane may be any one having two or more hydrogen atoms (i.e., SiH groups) bonded to a silicon atom in one molecule, and the molecular structure of this organohydrogenpolysiloxane is May be any of linear, cyclic, branched, and three-dimensional network structures, but the number of silicon atoms in one molecule (that is, the degree of polymerization) is 2 to 1000, and particularly about 2 to 300. It 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 end (on the way). Further, examples of the organic group bonded to a silicon atom other than a hydrogen atom include an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond similar to R ^{1 in the} general formula (Formula 1). .

  As the organohydrogenpolysiloxane of the component B, one having the following structure can be exemplified.

  In the above formulae, 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. )

(3) Catalyst component (C component)
The catalyst component of component C is a component that accelerates the curing of the present composition. As component C, a known catalyst can be used as a catalyst used for the hydrosilylation reaction. For example, platinum black, second platinum chloride, chloroplatinic acid, reaction product of chloroplatinic acid and monohydric alcohol, complex of chloroplatinic acid with olefins and vinylsiloxane, platinum-based catalyst such as platinum bisacetoacetate, palladium-based The catalyst includes platinum group metal catalysts such as rhodium based catalysts. The compounding amount of the component C may be any amount necessary for curing, and can be appropriately adjusted according to the desired curing speed and the like. 0.01-1000 ppm is added as a metal atom weight with respect to A component.

(4) Thermally conductive particles (D component)
When heat conductive particles of component D are added, 100 to 2000 parts by weight of 100 parts by weight of the matrix component are added. This can increase the thermal conductivity. The heat conductive particles are preferably at least one selected from alumina, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide and silica. Various shapes such as spherical, scaly and polyhedral shapes can be used. When alumina is used, α-alumina having a purity of 99.5% by weight or more is preferable. The specific surface area of the thermally conductive particles is preferably in the range of 0.06 to 10 m ² / g. The specific surface area is a BET specific surface area, and the measurement method conforms to JIS R1626. When using an average particle diameter, the range of 0.1-100 micrometers is preferable. The particle diameter is measured by a laser diffraction light scattering method to measure the 50% particle diameter. As this measuring instrument, there is, for example, a laser diffraction / scattering particle distribution measuring apparatus LA-950S2 manufactured by Horiba, Ltd.

  The heat conductive particles are preferably used in combination of at least two inorganic particles having different average particle sizes. In this way, the thermally conductive inorganic particles having a small particle size are embedded between the large particle sizes, and can be packed in a close-packed state, resulting in high thermal conductivity.

The inorganic particle is R (CH ₃ ) _a Si (OR ′) _3-a (R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or It is preferable to surface-treat with the silane compound shown by 1), or its partial hydrolyzate. R (CH ₃ ) _a Si (OR ′) _3-a (R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) The alkoxysilane compound (hereinafter referred to simply as "silane") is, by way of example, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxy Silane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecyltriethoxysilane, hexadodecyltrimethoxysilane, hexadodecyltriethoxysilane, octadecyltrimethoxysilane, Octadecyltriethoxy There are silane compounds such as Sisilane. The said silane compound can be used 1 type or in mixture of 2 or more types. As a surface treatment agent, alkoxysilane and one-end silanol siloxane may be used in combination. The surface treatment mentioned here includes adsorption as well as covalent bonding. The particles having an average particle diameter of 2 μm or more are preferably added in an amount of 50% by weight or more based on 100% by weight of the whole particles.

( 5 ) Other components In the composition of the present invention, other components can be blended as needed. For example, an inorganic pigment such as bengara, an alkyltrialkoxysilane or the like may be added for the purpose of surface treatment of a filler and the like. As a material to be added for the purpose of filler surface treatment, an alkoxy group-containing silicone may be added.

As an example of a compound containing an alkoxysilyl group and an amino group or an azide group, triethoxysilylpropylamino-1,3,5-triazine-2,4-ethylenediamine (hereinafter referred to as “A-TES”) shown in the following (Chem. 6) ), Triethoxysilylpropylamino-1,3,5-triazine-2,4-azide (hereinafter referred to as “P-TES”) shown in the following (chemical formula 7), aminoethylaminopropyltrimethoxysilane: (CH ₃ O) ) there are _{3 SiCH 2 CH 2 CH 2 NHCH} 2 CH 2 NH 3 or the like.

  The compound shown in the above (Chemical formula 6) reacts with the base sheet and is covalently bonded as shown in the following (Chemical formula 8) (wherein n is an integer of 1 or more). The compound shown in the above (Chemical formula 7) reacts with the substrate sheet to be covalently bonded as shown in the following (Chemical formula 9). In particular, the reaction shown in the following (Chemical Formula 9) is strong, can be applied to most resins, and can be applied to metals. In Chemical Formulas 8 to 9, alkoxysilyl groups react with and thermally bond to a thermally conductive silicone rubber. Aminoethylaminopropyltrimethoxysilane is also covalently bonded by the same chemical reaction as (Chemical Formula 8).

  This will be described below with reference to the drawings. In the following drawings, the same symbols indicate the same things. FIG. 1A is a perspective view of a composite sheet according to an embodiment of the present invention, and FIG. 1B is an enlarged cross-sectional view taken along the line II of FIG. 1A. The composite sheet 1 is wound around a winding core 4 in a roll shape. As an example, it is a long roll body 150 mm wide. In the cross-sectional view, the heat conductive silicone rubber sheet 2 is integrally laminated on the surface of the base sheet 3. As an example, the thickness of the substrate sheet 3 is 0.025 mm, the thickness of the thermally conductive silicone rubber sheet 2 is 0.175 mm, and the total thickness is 0.20 mm.

  FIG. 2A is a cross-sectional view showing the smoothing process of the thermally conductive silicone rubber sheet by calendering, and FIG. 2B is a cross-sectional view of the thermally conductive silicone rubber sheet after calendering. A pair of calender rolls 7a and 7b having a predetermined clearance, the thermally conductive silicone rubber sheet 2 after molding and curing, the smooth polyethylene terephthalate film 5 on the surface side, and the polyethylene terephthalate embossed on the back surface The film 6 is placed, supplied and calendered. When such calendering is performed, the smooth surface of the polyethylene terephthalate film 5 is transferred to the thermally conductive silicone rubber sheet 2, and the surface 2a of the thermally conductive silicone rubber sheet 2 becomes a smooth surface. The surface 2a of a conventional heat conductive silicone rubber sheet before calendering has an arithmetic mean roughness Ra of about 5 μm, but the arithmetic mean roughness Ra after calendering is 4 μm or less, preferably 3 μm or less, more preferably It is 2 μm or less. The lower limit is preferably as small as possible, but is practically 0.1 μm or more. The back surface 2b of the heat conductive silicone rubber sheet 2 becomes an uneven surface by embossing. Thereafter, the wound body 8 is taken. Arithmetic mean roughness Ra of the uneven surface by embossing is preferably 5 μm to 20 μm from the viewpoint of good handleability.

  FIGS. 3A to 3E are explanatory views of the surface coating process of the polyimide film by the bar coater. As an example, prepare a polyimide film 3 of 300 mm long, 200 mm wide, and 50 μm thickness (FIG. 3A), stick the resin tape 13 on the upper side, and use the dropper 11 on the surface of the polyimide film 3 -Drop a predetermined amount of diluted solution 12 diluted with the water mixture (Figure 3B). Then, it is stretched into a thin film 15 by a bar coater 14 (FIG. 3C). After air drying, cut 50 mm long and 100 mm wide using a cutter (FIG. 3D). 16a-f are cut lines. The resulting surface coated film 17 is shown in FIG. 3E.

  FIGS. 4A to 4D are explanatory views of pressure bonding of the thermally conductive silicone rubber sheet 18 after the smoothing process by calendar processing and the surface activation process by corona treatment, and the polyimide film 17 after the surface process. As the heat conductive silicone rubber sheet 18, for example, product name "Surcon TR" (50 mm in length, 100 mm in width, 0.18 mm in thickness) manufactured by Fuji Highpolymer Co., Ltd. is used, and, for example, arithmetic average roughness Ra1 after calendering Corona-treated to a smooth surface of ̃1.5 μm. The corona treatment is performed, for example, three times at 14 kV and a speed of 1.8 m / min using a trade name "Corona scanner ASA-4" manufactured by Shinko Electric Instruments Co., Ltd. A release paper 19 (15 mm in length, 100 mm in width) is placed on one end of the corona-treated surface of the heat conductive silicone rubber sheet 18 obtained, and the surface-treated surface of the film 17 is bonded (FIG. 4A). Bonding was performed by rubber roller hooking. Next, the acrylic resin plates 20a and 20b are stacked on the outside of the bonded body 24, the iron plates 21a and 21b are stacked on the outside, and the bolts and the nuts 22a and 22b are crimped. The pressure at this time is, for example, 3.6 cN (0.03 MPa) (FIG. 4B). Next, it is placed in an oven of a predetermined temperature and heated for 1 hour. In the case of continuous production, a heating and pressurizing apparatus provided with pressurizing means in the heating chamber is used. The composite sheet 25 thus pressure-bonded was taken out of the oven and cut as cut lines 23a-d (FIG. 4C) to obtain a composite sheet sample 26 of 50 mm long and 25 mm wide. The composite sheet sample 26 is composed of a portion of the composite sheet 25 and a portion of the release paper 19, and the portion of the release paper 19 is used to be a holding portion at the time of peeling test. There is no part of the release paper 19 in a normal product.

  This will be described using the following examples. The invention is not limited to the examples.

<Measurement method of average roughness>
The surface roughness was measured using a "Laser Focus Displacement Meter LT-8010" manufactured by Keyence Corporation. The number of measurements was 3 and the average value was calculated.
<Peeling test>
It peeled by the tension tester according to JISK6854-2. The number of measurements was 3 and the average value was calculated.

(Examples 1 to 6, Comparative Example 1)
(1) Adhesive Compound As an adhesive molecule, A-TES shown in the above (Chemical Formula 6) was used. The dilution solution was used as a 70% ethanol-water mixed solution for industrial use, adjusted to a dilute solution with an A-TES concentration of 0.001 to 0.1% by mass. 1% by mass (Example 1), 0.5% by mass (Example 2), 0.01% by mass (Example 3), 0.005% by mass (Example 4), 0.001% by mass (Examples) 5), 0.005% by mass (Example 6), and 0.001% by mass (Comparative Example 1).
(2) Base Material Sheet and Surface Coating Treatment As a base material sheet, a polyimide film: trade name "Kapton 200H" (a thickness of 50 μm) manufactured by Toray DuPont Co., Ltd. was used. This polyimide film is cut into a length of 300 mm and a width of 200 mm as shown in FIGS. 3A-E, a resin tape is attached to the upper side, and the adhesive compound: A-TES 70% ethanol -A predetermined amount of the diluted solution 12 diluted with the water mixture was dropped (Fig. 3B). Then, it was stretched into a thin film 15 by a bar coater (No. 3 manufactured by Yasuda Seiki Seisakusho Co., Ltd.) 14 (FIG. 3C). After air drying, it was cut into 50 mm long and 100 mm wide using a cutter (FIG. 3D). The applied thickness of A-TES after drying of a sample having a concentration of 0.1% by mass of A-TES diluted with a 70% ethanol-water mixed solution for industrial use is 6.9 nm, and the sample of 0.01% by mass same The dry thickness of the powder was 0.69 nm.
(3) Thermally conductive silicone rubber sheet and its smoothing treatment and surface activation treatment As a thermally conductive silicone rubber sheet, Fuji Polymer Industries, Ltd. make, brand name "Surcon TR" (thickness 0.18 mm) was used. The thermal conductivity of this thermally conductive silicone rubber sheet is 1.2 W / m · K. This heat conductive silicone rubber sheet was calendered by the method shown in FIG. 2A, and the arithmetic mean roughness Ra on the side of the laminated surface was 1.2 μm. This surface was a smooth surface having gloss. The non-laminated side was embossed. Next, the heat conductive silicone rubber sheet was cut into a length of 50 mm and a width of 100 mm, and the smooth surface was corona treated. The corona treatment was performed three times at 14 kV and a speed of 1.8 m / min using Shinko Electric Instrumentation Co., Ltd. trade name "Corona scanner ASA-4".
(4) Lamination integration Release paper 19 (15 mm long, 100 mm wide) was placed on one end of the corona-treated surface of the obtained heat conductive silicone rubber sheet, and the surface-treated surface side of the polyimide film was bonded ( Figure 4A). Bonding was performed by rubber roller hooking. Next, an acrylic resin plate was stacked on the outside of the bonded body, an iron plate was stacked on the outside, and pressure bonding was performed using a bolt and a nut. The pressure at this time was 3.6 cN (0.03 MPa) (FIG. 4B). Then, it was placed in an oven at a temperature of 120 ° C. and heated for 1 hour. The composite sheet thus pressure-bonded was taken out of the oven and cut as cut lines 23a-d (FIG. 4C) to obtain a composite sheet sample 26 of 50 mm long and 25 mm wide. The composite sheet sample 26 was composed of a portion of the composite sheet 25 and a portion of the release paper 19, and the portion of the release paper 19 was used to be a holding portion at the time of the peeling test. The results are summarized in Table 1 and FIG.

(Examples 7 to 12, Comparative Example 2)
It implemented similarly to Examples 1-4 and Comparative Example 1 except pressure bonding temperature having been 100 ° C. The results are summarized in Table 2 and FIG. The relationship between the A-TES concentration and the A-TES dry mass (coating amount) is the same as in Table 1 and therefore will be omitted in the following table.

(Examples 13 to 18, Comparative Example 3)
It implemented similarly to Examples 1-4 and the comparative example 1 except pressure bonding temperature having been 70 degreeC. The results are summarized in Table 3 and FIG.

As shown in Tables 1 to 3 and FIG. 5, it was confirmed that the peeling state is cohesive failure and Examples 1 to 8 have high adhesive strength. On the other hand, all of Comparative Examples 1 to 3 were interfacial failure, and adhesion was zero. As shown in FIG. 5, A-TE S concentration is likewise interfacial fracture 0.001 wt% or less, the adhesive force was zero.

(Examples 19 to 22)
As a heat conductive silicone rubber sheet, Fuji Polymer Industries, Ltd. make, brand name "Surcon TR" (thickness 1.2 mm) was used, and it was set as the smooth surface of arithmetic mean roughness Ra1.2micrometer on both surfaces by press molding. This smooth surface had a gloss. The laminated side was corona treated. The corona treatment was performed once at 14 kV and at a speed of 1.8 m / min using Shinko Electric Instrumentation Co., Ltd. trade name "Corona scanner ASA-4". A-TES was diluted with an industrial 70% ethanol-water mixed solution to a concentration of 0.1% by mass, and the polyimide film was immersed in this solution, taken out, and air-dried. The pressure bonding conditions were 45 ° C. for 0.2 to 5 hours, and the pressure was 0.03 MPa. The results are summarized in Table 4 and FIG.

(Comparative example 4)
As a heat conductive silicone rubber sheet, Fuji Polymer Industries, Ltd. make, brand name "Surcon TR" (thickness 0.18 mm) was used as it was, and surface smooth processing was not performed. The experiment was performed in the same manner as Example 4 except for the above. The adhesive strength of the obtained laminate was 0 kgf / 25 mm, and was interfacial peeling.

(Examples 23 to 31)
As an adhesion molecule, Toray Dow Corning Co., Ltd. trade name "OFS-6020": aminoethylaminopropyltrimethoxysilane: (CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NH ₃ (referred to as aminosilane) is used And diluted with ion exchange water to a silane concentration of 1.0% by mass. Further, a 1.0% by mass aqueous silane solution was diluted with industrial ethanol (purity 70% by mass) to obtain a silane concentration of 0.1% by mass and 0.01% by mass. The other conditions were the same as in Example 1. Conditions and results are shown in Table 5.

  As shown in Table 5, when the concentration of the aminosilane was 0.01% by mass, the ratio of interfacial failure was high, but the other was cohesive failure. From the above results, it can be seen that aminosilane is also effective.

  The composite sheet of the present invention is useful as a cushioning material or the like interposed between a pressing member of a heating and pressing press and a product to be pressed because the dimensional stability and durability are high.

1 composite sheet 2 heat conductive silicone rubber sheet 2a smooth surface 2b embossed surface 3 substrate sheet (polyimide film)
Reference Signs List 4 core 5 surface smooth polyethylene terephthalate film 6 embossed polyethylene terephthalate film 7a, 7b calender roll 8 wound body 11 dropper 12 adhesive compound diluted solution 13 resin tape 14 bar coater 15 thin film 16a-16f, 23a-23d cut line 17 surface treatment Thermal conductivity silicone rubber sheet 19 after surface activation treatment of polyimide film 18 after release paper 20a, 20b acrylic resin plate 21a, 21b iron plate 22a, 22b bolt and nut 24 bonded body 25 composite sheet 26 composite sheet sample

Claims (11)

A composite sheet in which a layer including a substrate sheet made of a polyimide film and a thermally conductive silicone rubber sheet layer is integrally laminated,
The thermal conductivity of the thermally conductive silicone rubber sheet layer is 0.6 W / m · K or more,
The laminated and integrated surface of the heat conductive silicone rubber sheet layer is made to be a smooth surface by calendering, and the smooth surface is at least one surface activated selected from corona, plasma, ultraviolet light and electron beam irradiation,
The base sheet and the thermally conductive silicone rubber sheet layer are integrally laminated by covalent bonding through a compound containing nitrogen (N) and silicon (Si), and the peeling portion of the laminated surface is cohesively broken. A composite sheet characterized by being in a state.   The composite sheet according to claim 1, wherein the cohesive failure of the laminated surface occurs on the heat conductive silicone rubber sheet layer side. The composite sheet according to claim 1 or 2 , wherein the compound containing nitrogen (N) and silicon (Si) is a compound containing an alkoxysilyl group and an amino group or an azide group. The compound containing an alkoxysilyl group and an amino group or an azide group is triethoxysilylpropylamino-1,3,5-triazine-2,4-ethylenediamine, triethoxysilylpropylamino-1,3,5-triazine-2 4. The composite sheet according to claim 3, wherein the composite sheet is at least one selected from 2,4-azido and aminoethylaminopropyltrimethoxysilane.   The composite sheet according to any one of claims 1 to 4, wherein the covalent bond between the base sheet and the thermally conductive silicone rubber sheet layer is in a state of single molecule adhesion or multiple molecule adhesion. A method of manufacturing the composite sheet according to any one of claims 1 to 5 ,
Calendering a thermally conductive silicone rubber sheet with a thermal conductivity of 0.6 W / m · K or more, making at least the laminated surface a smooth surface,
The smooth surface is subjected to at least one surface activation treatment selected from corona, plasma, ultraviolet light and electron beam irradiation,
Coating a compound containing nitrogen (N) and silicon (Si) on the laminated surface of at least one substrate sheet selected from a resin sheet and a metal sheet,
A method of manufacturing a composite sheet, wherein the base sheet and the thermally conductive silicone rubber sheet layer are pressure-bonded and integrally laminated. The method for producing a composite sheet according to claim 6 , wherein the smooth surface of the thermally conductive silicone rubber sheet layer has an arithmetic average roughness Ra of 3 μm or less. The method for producing a composite sheet according to claim 6 or 7 , wherein the compound containing nitrogen (N) and silicon (Si) is a compound containing an alkoxysilyl group and an amino group or an azide group. The method for producing a composite sheet according to any one of claims 6 to 8 , wherein the compound containing nitrogen (N) and silicon (Si) is coated by diluting with at least one diluent selected from water and an organic solvent. The method for producing a composite sheet according to any one of claims 6 to 9 , wherein the coating amount per unit area of the compound containing nitrogen (N) and silicon (Si) is 0.0011 g / m ² or more in dry mass. . The composite according to any one of claims 6 to 10 , wherein the lamination integration of the base sheet and the heat conductive silicone rubber sheet layer is performed by at least one pressure selected from roll pressure and plate pressure. Sheet manufacturing method.