JP6553520B2 - Thermally conductive cured product, adhesive tape and adhesive sheet having the cured product - Google Patents

Description

  The present invention relates to a heat transfer material that can be interposed at the interface between the thermal interface of a heat-generating electronic component and a heat-generating member such as a heat sink or a circuit board for cooling the electronic component. In detail, it is related with the heat conductive hardened | cured material which has heat conductivity and adhesiveness, and the adhesive tape and adhesive film which have this hardened | cured material.

  Transistors and diodes used in converters, power supplies, and other electronic devices, and heating elements such as LED elements that serve as light sources for lighting and displays are becoming more sophisticated, faster, smaller, and more integrated. It generates a large amount of heat. There is a problem that the heat generated by the heater element raises the temperature of the device, causing malfunction or destruction. For this reason, many heat dissipating methods and heat dissipating members have been developed to suppress the temperature rise of the heating element during operation.

  Conventionally, in order to suppress the temperature rise of the heat generating element during operation in electronic equipment, heat is generated between the heat generating element and a cooling member such as a heat sink or a housing using a metal plate having high thermal conductivity such as aluminum or copper. A conductive material is interposed, heat generated from the heating element is transmitted to the cooling member, and is radiated to the outside due to a temperature difference from the atmosphere. As the heat conductive material, a heat conductive sheet having an insulating property is often used. Screws or clips are used to fix the cooling member and the heating element, and the heat conductive sheet is also fixed by pressing with the screws or clips. However, the method of fixing with a screw or clip must go through the process of preparing a screw or clip and making a hole for screwing in a housing, a heating element, a substrate, etc. Both processes will increase. Therefore, it is very disadvantageous when considering the manufacturing efficiency. In addition, parts such as screws and clips prevent the electronic device itself from being reduced in size and thickness, which is also disadvantageous in terms of product design.

  Therefore, a method is considered in which the heat conductive sheet interposed between the cooling member and the heat generating element is made adhesive to fix the housing and the heat generating element. For example, Patent Document 1 describes a thermally conductive sheet with an adhesive in which an adhesive is applied to both sides of a thermally conductive sheet. However, since the pressure-sensitive adhesive itself has no heat conductivity, the heat conduction sheet having the pressure-sensitive adhesive significantly deteriorates the heat transfer. Therefore, a heat conductive composition in which a heat conductive filler is mixed with an adhesive has been developed. From the viewpoint of heat resistance, cold resistance, and durability of the resulting cured product, heat conduction using silicone as a polymer. Sex compositions have been developed. For example, Patent Document 2 describes a silicone heat-dissipating sheet having self-adhesiveness. Patent Document 3 describes a pressure-sensitive adhesive silicone composition for a heat dissipation member in which a pressure-sensitive adhesive is highly filled with a heat conductive filler. Patent Document 4 describes a silicone cured product having thermal conductivity and adhesiveness. Moreover, the thermally conductive adhesive tape which filled the adhesive material with the thermally conductive filler is known (patent documents 5, 6, 7). In particular, a thermally conductive silicone pressure-sensitive adhesive tape using silicone as a polymer is known from the viewpoint of its heat resistance, cold resistance and durability (Patent Document 8). However, the thermal conductivity is less than 1 W / mK, and it can not be applied where high thermal conductivity is required.

JP, 2005-60594, A JP, 2008-112894, A Unexamined-Japanese-Patent No. 2004-99842 JP 2008-260798 A JP 2014-34652 A JP, 2014-62220, A Unexamined-Japanese-Patent No. 2002-121529 JP 2008-260798 A

However, the thermal conductivity and the adhesive force are in a contradictory relationship, and when the thermally conductive filler is added to the adhesive, the adhesive property is impaired. Therefore, in order to fix a heating element such as a semiconductor element using a heat conductive adhesive tape as described in the above-mentioned patent documents, it is necessary to apply a high pressure for a certain period of time. However, since the heat generating element is a precision part, it may be damaged if pressure is applied to the element when it is fixed, and it is desirable to avoid applying high pressure. Moreover, since the time for fixing a heat generating element is needed as mentioned above, it becomes disadvantageous from a viewpoint of manufacturing efficiency. Therefore, a heat conductive pressure-sensitive adhesive tape that can fix the heating element at a low pressure in a short time is desired. That is, development of the heat conductive adhesive tape which has high adhesive force is desired.
In addition, with the downsizing and weight reduction of electronic devices, the demand for thermally conductive silicone adhesive tapes has increased, and there is a desire for thermally conductive silicone adhesive tapes with high thermal conductivity that can be applied to parts with high heat generation. There is.

  The present invention provides a curable silicone composition which gives a thermally conductive cured product having high thermal conductivity and high adhesiveness, and obtained by curing the curable silicone composition. An object of the present invention is to provide a pressure-sensitive adhesive tape (including a pressure-sensitive adhesive film) comprising the cured product on the surface of a sheet-like substrate.

  As a result of intensive studies in view of the above circumstances, the present inventors have found a curable silicone composition that can contain an extremely large amount of a thermally conductive filler, and have found that the above object can be achieved.

（式中、Ｒ¹は互いに独立に炭素原子数６〜１５のアルキル基であり、Ｒ^２は互いに独立に非置換又は置換の炭素原子数１〜１０のアルキル基であり、Ｒ³は互いに独立に炭素原子数１〜６のアルキル基であり、ａは１〜３の整数、ｂは０〜２の整数であり、但しａ＋ｂは１〜３の整数である）、

（式中、Ｒ⁴は互いに独立に炭素原子数１〜６のアルキル基であり、ｃは５〜１００の整数である）。
さらに本発明は、該硬化性シリコーン組成物を硬化させて得られた硬化物をシート状基材の面上に備える粘着テープ（粘着フィルムを包含する）を提供する。
That is, the present invention provides a curable silicone composition comprising the following components (a) to (g).
(A) 100 parts by mass of an organopolysiloxane having an alkenyl group,
(B) thermally conductive filler 4000 to 13000 parts by mass,
(C) Organohydrogenpolysiloxane (a) An amount in which the ratio of the number of hydrogen atoms bonded to silicon atoms in the component (c) to the number of alkenyl groups in the component is 0.5 to 3,
(D) Addition reaction catalyst Catalytic amount (e) 10 to 50,000 ppm with respect to the mass of the reaction control agent (a) component
(F) Silicone resin 280 to 600 parts by mass (g) Compound having 1 to 3 alkoxy groups represented by the following general formula (1) or (2) 80 to 300 parts by mass

(Wherein, R ¹ is each independently an alkyl group having 6 to 15 carbon atoms, R ² is each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, and R ³ is mutually independent Is an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3),

(In the formula, R ⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100).
The present invention further provides an adhesive tape comprising a cured product obtained by curing the curable silicone composition on the surface of the sheet-like substrate (you include an adhesive film).

  The thermally conductive cured product obtained by curing the curable silicone composition of the present invention has high thermal conductivity and high adhesion. Therefore, the heat generating element can be fixed at a low pressure and in a short time, and a highly reliable heat generating element device can be provided. Furthermore, the production efficiency can also be mentioned. Therefore, the thermally conductive cured product of the present invention can be suitably used as a thermally conductive member interposed between the cooling member and the heating element.

Hereinafter, the silicone composition of the present invention will be described in detail.
(A) Organopolysiloxane Having an Alkenyl Group The organopolysiloxane having an alkenyl group is not particularly limited as long as it is used for an addition reaction curable silicone composition. Specifically, it has two or more alkenyl groups bonded to a silicon atom in one molecule. The organopolysiloxane may have a linear structure in which the main chain portion is composed of repeating diorganosiloxane units, a structure containing a branched chain in a part of the molecular structure, or a cyclic structure. Of these, linear organopolysiloxane is preferable from the viewpoint of physical properties such as mechanical strength of the cured product.

  The alkenyl group has 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms. For example, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group etc. are mentioned. Among them, a lower alkenyl group such as a vinyl group or an allyl group is preferable, and a vinyl group is particularly preferable.

  The group to be bonded to a silicon atom other than the above alkenyl group may be a monovalent hydrocarbon group having no unsubstituted or substituted aliphatic unsaturated bond. The monovalent hydrocarbon group preferably has 1 to 12 carbon atoms, preferably 1 to 10, and more preferably 1 to 6 carbon atoms. For example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc. Alkyl group; cycloalkyl group such as cyclopentyl group, cyclohexyl group and cycloheptyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group and biphenylyl group; benzyl group, phenylethyl group, phenylpropyl group, methyl benzyl group Aralkyl groups such as groups; and groups in which part or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms such as fluorine, chlorine and bromine, or cyano groups, for example Chloromethyl group, 2-bromoethyl group, 3-chloropropyl group, 3,3, - trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, and 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, and the like. Among them, an unsubstituted or substituted alkyl group having 1 to 3 carbon atoms and an unsubstituted or substituted phenyl group are preferable, and a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, 3,3,3- A trifluoropropyl group, a cyanoethyl group, a phenyl group, a chlorophenyl group, a fluorophenyl group and the like are suitably used. All the groups other than the alkenyl group bonded to the silicon atom may be the same or a combination of two or more groups.

The organopolysiloxane preferably has a kinematic viscosity 10~100,000mm ² / s, in particular in the range of 500~50,000mm ² / s at 25 ° C.. If the kinematic viscosity is less than the above lower limit value, the storage stability of the curable silicone composition becomes worse. If the kinematic viscosity is above the above upper limit, the extensibility of the curable silicone composition may be deteriorated. The above-mentioned kinematic viscosity can be measured by a Cannon-Fenske viscometer.

式中、Ｒ^２は、互いに独立に、非置換又は置換の脂肪族不飽和結合を有さない１価炭化水素基であり、Ｒ^４は、互いに独立に、アルケニル基である。Ｒ^２及びＲ^４の詳細は上記した通りである。ａは０〜３の整数であり、好ましくは１であり、特には両末端においてａ＝１であるのがよい。ｐは０以上の整数であり、但しａとｐは同時に０にならない。ｑは１以上の整数であり、ｐ＋ｑは、上記オルガノポリシロキサンの２５℃における動粘度が１０〜１０００００ｍｍ^２／ｓ、特には５００〜５００００ｍｍ^２／ｓとなる値である。ｑは好ましくは１０〜１０００００の整数であり、さらには５０〜２０００の整数であり、特には１００〜１０００の整数である。ｐは０≦ｐ／（ｐ＋ｑ）≦０．５を満たすのがよく、さらには０≦ｐ／（ｐ＋ｑ）≦０．１を満たすのがよい。 The alkenyl group-containing organopolysiloxane is represented by the following formula, for example.

In the formula, R ² is, independently of one another, a monovalent hydrocarbon group having no unsubstituted or substituted aliphatic unsaturated bond, and R ⁴ is, independently of one another, an alkenyl group. The details of R ² and R ⁴ are as described above. a is an integer of 0 to 3, preferably 1, and it is particularly preferable that a = 1 at both ends. p is an integer of 0 or more, provided that a and p are not 0 at the same time. q is an integer of 1 or more, p + q has a kinematic viscosity at 25 ° C. of the organopolysiloxane 10~100000mm ² / s, in particular a value which becomes 500~50000mm ² / s. q is preferably an integer of 10 to 100000, further an integer of 50 to 2000, and particularly an integer of 100 to 1000. p should satisfy 0 ≦ p / (p + q) ≦ 0.5, and further preferably 0 ≦ p / (p + q) ≦ 0.1.

  The above organopolysiloxanes may be used alone or in combination of two or more having different viscosity and structure.

(B) Thermally Conductive Filler The thermally conductive filler can be a conventionally known thermally conductive filler blended in a thermally conductive composition. For example, nonmagnetic metals such as copper and aluminum, metal oxides such as alumina, silica, magnesia, bengara, beryllia, titania, zirconia and zinc oxide, metal nitrides such as aluminum nitride, silicon nitride and boron nitride, hydroxide Examples thereof include metal hydroxides such as magnesium, artificial diamond, and silicon carbide. These may be used alone or in combination of two or more. When manufacturing the adhesive tape which requires insulation, a metal oxide, aluminum nitride, and boron nitride are preferable. More preferably, it is alumina.

  The thermally conductive filler preferably has an average particle size of less than 20 μm, more preferably less than 10 μm. The average particle diameter in the present invention is a volume-based value measured using a Microtrac MT3300EX (Nikkiso), which is a laser diffraction / scattering type particle size distribution measuring device.

  Furthermore, in the thermally conductive filler, the content of particles having a particle diameter of 45 μm or more is preferably 0.5 wt% or less, more preferably 0.3 wt% or less, and further preferably 0.2 wt% It is below. In addition, the content of particles having a particle diameter of 75 μm or more is preferably 0.1 wt% or less, more preferably 0%. If the content of particles (so-called, coarse particles) having a particle diameter of 45 μm or more is larger than the above value, the surface roughness of the resulting thermally conductive cured product may be deteriorated. In particular, in the case of producing a tape having a cured product with a thickness of 50 μm or less, if the particle includes particles whose particle size is larger than the thickness of the cured product, the particles project on the surface of the cured product to deteriorate the surface accuracy. If the surface accuracy deteriorates, the contact area with the adherend decreases, so that sufficient tack force can not be obtained, and the heat conductivity is also impaired.

  The amount of the thermally conductive filler blended in the silicone composition of the present invention is 4000 to 13000 parts by mass, more preferably 4000 to 9000 parts by mass with respect to 100 parts by mass of the component (a). If the amount of the thermally conductive filler is less than the above lower limit, the cured product can not be provided with sufficient thermal conductivity. Moreover, since the adhesive force of hardened | cured material will fall that the quantity of a heat conductive filler is more than the said upper limit, it is unpreferable.

(C) Organohydrogenpolysiloxane The organohydrogenpolysiloxane is a crosslinking agent and has at least 2, preferably 3 or more hydrogen atoms bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be linear, branched, or cyclic. The organohydrogenpolysiloxane preferably has a viscosity of 1 to 5,000 mPa · s at 25 ° C., more preferably 5 to 500 mPa · s. The viscosity can be measured using a BM rotational viscometer. As the organohydrogenpolysiloxane, conventionally known ones can be used.

式中、Ｒ^３は炭素数１〜１０の１価炭化水素基であり、ｂは０または１であり、ｒ及びｓは０以上の整数であり、但し、該オルガノハイドロジェンポリシロキサンの２５℃における粘度が１〜５,０００ｍＰａ・ｓ、好ましくは５〜５００ｍＰａ・ｓとなる値である。また、ｂ＋ｒは、ケイ素原子に結合した水素原子を１分子中に少なくとも２個、好ましくは３個以上有する値である。ｔは２以上の整数であり、ｖは０以上の整数であり、かつｔ＋ｖ≧３であり、好ましくは８≧ｔ＋ｖ≧３である。オルガノハイドロジェンポリシロキサンは２種以上の混合物であってもよい。 Examples of the organohydrogenpolysiloxane include linear siloxanes and cyclic siloxanes represented by the following formulas.

In the formula, R ³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms, b is 0 or 1, r and s are integers of 0 or more, provided that 25 ° C. of the organohydrogenpolysiloxane The viscosity is 1 to 5,000 mPa · s, preferably 5 to 500 mPa · s. Further, b + r is a value having at least two, preferably three or more hydrogen atoms bonded to a silicon atom in one molecule. t is an integer of 2 or more, v is an integer of 0 or more, and t + v ≧ 3, preferably 8 ≧ t + v ≧ 3. The organohydrogenpolysiloxane may be a mixture of two or more.

R ³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms. For example, alkyl groups such as methyl group, ethyl group, propyl group and butyl group; cycloalkyl groups such as cyclohexyl group; aryl groups such as phenyl group and tolyl group; and alkenyl groups such as vinyl group and allyl group Be Particularly preferred is a methyl group or a phenyl group.

  Examples of the organohydrogenpolysiloxane include methylhydrogenpolysiloxane having both molecular chain ends blocked with trimethylsiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymer having both molecular chain ends blocked with trimethylsiloxy groups, Dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer blocked at both ends of molecular chain with trimethylsiloxy group, dimethylpolysiloxane blocked at both ends of molecular chain with dimethylhydrogensiloxy group, dimethylpolysiloxane at both ends of molecular chain Dimethylsiloxane / methylhydrogensiloxane copolymer blocked with hydrogensiloxy group, dimethylsiloxane / methylphenylsiloxax with both ends of molecular chain blocked with dimethylhydrogensiloxy group Copolymers, both molecular chain terminals with dimethylhydrogensiloxy methylphenyl polysiloxane blocked with group. The organohydrogenpolysiloxane may be used alone or in combination of two or more.

  The compounding amount of the component (c) in the silicone composition of the present invention is an amount such that the ratio of the number of SiH groups in the component (c) to the number of alkenyl groups in the component (a) is 0.5 to 3. Preferably, the amount is 0.8 to 2.5. When the amount of SiH groups in the component (c) is less than the above lower limit, the thermally conductive composition is not sufficiently cured, the strength of the cured product is insufficient, and cannot be handled as a molded product or a composite. Problems occur. Exceeding the upper limit is not preferable because the surface of the cured product becomes insufficient in tackiness.

(D) Addition reaction catalyst The addition reaction catalyst causes an addition reaction between the alkenyl group in the component (a) and the SiH group in the component (c) to convert the composition of the present invention into a cross-linked cured product of a three-dimensional network structure. It is a component blended for conversion, and may be a conventionally known addition reaction catalyst, and it is preferable to use a platinum group metal catalyst. Examples of the platinum group metal catalyst include platinum (including platinum black), platinum group metals such as rhodium and palladium, H ₂ PtCl ₄ .nH ₂ O, H ₂ PtCl ₆ .nH ₂ O, NaHPtCl _6. nH ₂ O, KHPtCl ₆ · nH ₂ O, Na ₂ PtCl ₆ · nH ₂ O, K ₂ PtCl ₄ · nH ₂ O, PtCl ₄ · nH ₂ O, PtCl ₂ , Na ₂ HPtCl ₄ · nH ₂ O (however, N in the formula is an integer of 0 to 6, preferably 0 or 6.) platinum chloride such as chloroplatinic acid and chloroplatinic acid salt, alcohol-modified chloroplatinic acid, complex of chloroplatinic acid and olefin Or platinum group metals such as platinum or palladium supported on a carrier such as alumina, silica, carbon, etc., rhodium-olefin complex, chlorotris (trif Sulfonyl phosphine) rhodium (Wilkinson's catalyst), platinum chloride, complexes and the like of chloroplatinic acid or chloroplatinic acid salts with vinyl-containing siloxanes. These catalysts may be used alone or in combination of two or more.

  The addition amount of the catalyst may be a catalytic amount. The catalytic amount is an effective amount for promoting the addition reaction of the component (a) and the component (c). Usually, it is 0.1 to 1,000 ppm, preferably 0.5 to 500 ppm in terms of the mass of the platinum group metal element with respect to the mass of the component (a).

(E) Reaction control agent The reaction control agent is for adjusting the rate of the addition reaction. The reaction control agent functions to prevent thickening and gelling of the composition before heat curing when the silicone composition is prepared and applied to a substrate, and is conventionally known. Reaction control agents can be used. For example, acetylene compounds such as 1-ethynyl-1-cyclohexanol, ethynylmethylidene carbinol and 3-butyn-1-ol, nitrogen compounds, organic phosphorus compounds, sulfur compounds, oxime compounds, organic chloro compounds and the like can be mentioned. These addition reaction inhibitors can be used alone or in combination of two or more.

  The compounding amount of the component (e) in the silicone composition of the present invention may be appropriately adjusted according to the amount of the component (d) used so as to set the progress of the addition reaction to a desired reaction rate. Usually, it is about 10 to 50,000 ppm, preferably 200 to 30,000 ppm, more preferably 1,000 to 20,000 ppm, based on the mass of the component (a). If the blending amount of the component (e) is too small, the storage stability of the composition of the present invention may be insufficient, and a sufficient usable time may not be secured. When the amount is too large, the curability of the composition of the present invention is unfavorably reduced.

(F) Silicone resin The silicone resin functions to impart tackiness to the surface of the cured product of the present invention. The silicone resin is in particular a polymer of R ₃ SiO _1/2 units (M units) and SiO _4/2 units (Q units). Any conventional silicone resin may be used as long as it has such a structure. Preferably, the ratio (molar ratio) of M units to Q units is M / Q = 0.5 to 1.5, more preferably 0.6 to 1.4, and in particular It is preferably 0.7 to 1.3. When the molar ratio between the M unit and the Q unit is within the above range, a desired adhesive force can be imparted to the cured product.

  R in the above formulas is, independently of one another, an unsubstituted or substituted monovalent hydrocarbon group which does not contain an aliphatic unsaturated bond. The number of carbon atoms is preferably 1 to 12, more preferably 1 to 10 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Examples of the group represented by R include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group Alkyl groups such as decyl group and dodecyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group and cycloheptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, xylyl group, naphthyl group and biphenylyl group; benzyl group , Aralkyl groups such as phenylethyl group, phenylpropyl group, and methylbenzyl group, and some or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atoms such as fluorine, chlorine, and bromine, Or a group substituted with a cyano group, such as a chloromethyl group, a 2-bromoethyl group, -Chloropropyl group, 3,3,3-trifluoropropyl group, chlorophenyl group, fluorophenyl group, cyanoethyl group, 3,3,4,4,5,5,6,6,6-nonafluorohexyl group etc. Can be mentioned. Among the above, C1-C3 unsubstituted or substituted alkyl group and unsubstituted or substituted phenyl group are preferable. For example, a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group, a cyanoethyl group, a phenyl group, a chlorophenyl group, and a fluorophenyl group can be suitably used. In particular, unless special characteristics such as solvent resistance are required, it is preferable that all R's are methyl groups in view of cost, availability, chemical stability, environmental load and the like.

Two or more kinds of the organopolysiloxane may be used in combination. It may also have a _{RSiO 1.5} units and / or _R 2 SiO units within a range not to impair the characteristics of the present invention. R is as described above.

  (F) The amount of silicone resin is 280 to 600 parts by mass, preferably 340 to 500 parts by mass. If this amount is less than the lower limit, the strength of the heat conductive silicone pressure-sensitive adhesive tape is insufficient, and sufficient adhesive strength cannot be obtained. When this amount exceeds the upper limit, it is difficult to uniformly mix the thermally conductive filler, and it becomes difficult to prepare the thermally conductive silicone composition.

  The silicone resin is usually a solid or viscous liquid at room temperature. In the present invention, it is also possible to use a silicone resin dissolved in a solvent. In that case, what is necessary is just to mix | blend so that the quantity of the silicone resin except the solvent part contained in a composition may satisfy | fill the said range. As the solvent, an organic solvent described later can be used.

（式中、Ｒ¹は互いに独立に炭素原子数６〜１５、好ましくは６〜１２のアルキル基であり、Ｒ^２は互いに独立に非置換又は置換の炭素原子数１〜１０、好ましくは１〜３のアルキル基であり、Ｒ³は互いに独立に炭素原子数１〜６、好ましくは１〜３のアルキル基であり、ａは１〜３の整数、ｂは０〜２の整数であり、但しａ＋ｂは１〜３の整数である。）
好ましくは、Ｒ^１がノニル基であり、Ｒ^３がメチル基であり、a=1,b=0 である化合物、Ｒ^１がオクチル基であり、Ｒ^３がエチル基であり、a=1,b=0 である化合物、あるいはＲ^１がオクチル基であり、Ｒ^２がメチル基であり、^Ｒ３がメチル基であり、a=1,b=1である化合物が例示される。

（式中、Ｒ⁴は互いに独立に炭素原子数１〜６、好ましくは１〜３のアルキル基であり、ｃは５〜１００、好ましくは５〜６０の整数である。）
（ｇ）成分の添加量は80〜300質量部、好ましくは100〜250質量部である。上記下限より少ないと、熱伝導性シリコーン組成物の調製が難しくなり、上記上限を超えると、本発明の硬化性組成物の硬化物が柔らかすぎて、剥離コーティングを行った剥離フィルムや剥離紙にシリコーン組成物を塗工し、硬化を行った後、上記基材に該フィルムの粘着層面を貼り合わせること（所謂、転写）が難しくなる。 (G) Alkoxy group-containing organopolysiloxane The component (g) is a compound having 1 to 3 alkoxy groups represented by the following general formula (1) or (2).

(Wherein, R ¹ is each independently an alkyl group having 6 to 15 carbon atoms, preferably 6 to 12 carbon atoms, and R ² is each independently an unsubstituted or substituted 1 to 10 carbon atoms, preferably 1 to 1 carbon atoms And R ³ is independently an alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, a is an integer of 1 to 3 and b is an integer of 0 to 2; a + b is an integer of 1 to 3.)
Preferably, a compound in which R ¹ is a nonyl group, R ³ is a methyl group, a = 1, b = 0, R ¹ is an octyl group, R ³ is an ethyl group, a = 1, b = 0 compound, or R ¹ is an octyl group, R ² is a methyl group, ^R3 is a methyl group, the compound is a = 1, b = 1 is illustrated.

(Wherein, R ^{4 's} are each independently an alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and c is an integer of 5 to 100 carbon atoms, preferably 5 to 60).
The addition amount of the component (g) is 80 to 300 parts by mass, preferably 100 to 250 parts by mass. When the content is less than the above lower limit, the preparation of the thermally conductive silicone composition becomes difficult, and when the content exceeds the above upper limit, the cured product of the curable composition of the present invention is too soft and the release film is coated with release coating. After the silicone composition is applied and cured, it becomes difficult to bond the adhesive layer surface of the film to the substrate (so-called transfer).

  In the silicone composition of the present invention, an organic solvent may be added to lower the viscosity at the time of coating. Examples of the organic solvent include aromatic solvents such as toluene and xylene, aliphatic solvents such as hexane, octane and isoparaffin, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, Ether solvents such as diisopropyl ether, 1,4-dioxane, etc., or mixed solvents of these or the like are used.

  In addition to the above-described components, optional components can be further added to the silicone composition of the present invention. For example, non-reactive polyorganosiloxanes such as polydimethyl siloxane and polydimethyl diphenyl siloxane; phenols, quinones, amines, phosphoruss, phosphites, sulfurs, thioethers, etc. antioxidants; triazoles, Examples include light stabilizers such as benzophenones; flame retardants such as phosphates, halogens, phosphoruss, and antimonys; and antistatic agents such as cationic surfactants, anionic surfactants, and nonionic surfactants.

  The silicone composition of the present invention is prepared by uniformly mixing the above-described components. The preparation method may follow conventionally known methods. The curing conditions of the composition are not particularly limited. For example, the temperature may be 60 to 150 ° C., preferably 80 to 150 ° C., for 30 seconds to 30 minutes, preferably 1 to 20 minutes.

[Thermal conductivity]
The thermal conductivity of the cured product of the curable composition is preferably 2.5 W / mK or more and 5 W / mK or less. If it is less than 2.5 W / mK, the heat conductivity is insufficient, and the higher the better, but if it is necessary to obtain a heat conductivity of more than 5 W / mK, it is necessary to be filled with a large number of heat conductive fillers. The preparation of conductive silicone compositions becomes difficult.
Thermal conductivity is measured by laser flash method after sandwiching an adhesive tape with a cured product of 100 μm thick curable composition on one side of the tape between two aluminum plates and pressing at a pressure of 20 psi for 1 hour at room temperature. The thermal resistance was measured, and the thermal conductivity was determined from the relationship between thickness and thermal resistance.

[Adhesive force]
The adhesion of the cured product of the curable composition of the present invention is preferably 0.1 MPa or more, more preferably 0.15 MPa or more. If the pressure is less than 0.1 MPa, the electronic component can not be sufficiently fixed. The adhesive strength was determined by sandwiching an adhesive tape having a cured product of a 100 μm thick curable composition on one side of a tape between two 10 × 10 mm square aluminum plates and applying a pressure of 20 psi at room temperature for 1 hour. The pressure-sensitive adhesive tape was peeled off to determine a shear stress.

  A pressure-sensitive adhesive tape or a pressure-sensitive adhesive film having a thermally conductive cured material layer (pressure-sensitive adhesive layer) is obtained by applying the silicone composition of the present invention to various sheet-like substrates and curing under predetermined conditions. it can. The base material on which the silicone composition is applied is not particularly limited. For example, polyester, polytetrafluoroethylene, polyimide, polyphenylene sulfide, polyamide, polyether ether ketone, polycarbonate, polystyrene, polypropylene, polyethylene, polyvinyl chloride and other plastic films; aluminum foil, copper foil and other metal foils; Japanese paper, synthetic Paper, paper such as polyethylene laminated paper; cloth; glass fiber; and sheet-like substrates such as composite substrates formed by laminating a plurality of these. In order to improve the adhesion between the silicone pressure-sensitive adhesive layer and the substrate, the substrate may be subjected to primer treatment, corona treatment, etching treatment, or plasma treatment in advance. Moreover, when peeling off the said base material from an adhesive layer at the time of mounting (namely, when using a base material as a separator), this base material may be surface-treated beforehand with a fluorine-type mold release agent. For example, modified silicones having a fluorine substituent such as a perfluoroalkyl group or a perfluoropolyether group in the main chain can be mentioned. As a commercial item, Shin-Etsu Chemical Co., Ltd. product X-70-201, X-70-258 grade | etc., Are mentioned.

  The manufacturing method of an adhesive tape and an adhesive film should just follow a conventionally well-known method. For example, it can be produced by applying a silicone composition on one surface of the substrate and curing it. When the composition is diluted with the above-mentioned solvent, it is preferable to volatilize the solvent before curing after coating the composition on the substrate. The coating method is not particularly limited, and examples thereof include a method of applying a liquid material in a thin film on the substrate using a bar coater, a knife coater, a comma coater, a spin coater or the like. In addition, after the silicone composition is applied to a release film or release paper on which release coating has been performed and cured, the adhesive layer surface of the film is attached to the above-mentioned base material (so-called transfer method). You can also.

  The coating amount of the composition is preferably such that the thickness of the resulting cured product is 20 to 500 μm, particularly 30 to 300 μm, and more particularly 30 to 200 μm. If the thickness of the cured product is less than the above lower limit, the handling may be poor and the adhesiveness may be reduced. If the thickness of the cured product exceeds the above upper limit, it is not preferable because the desired thermal conductivity may not be obtained.

  As a usage mode of the pressure-sensitive adhesive tape and the pressure-sensitive adhesive film of the present invention, for example, the heat generating element is fixed to the surface of the pressure-sensitive adhesive tape or the cured product of the pressure-sensitive adhesive film, By fixing the cooling member to the other surface of the exposed cured material layer, the cured material of the present invention can be interposed between the heat generating element and the cooling member. As described above, the cured product of the present invention has good thermal conductivity and high tackiness. Therefore, the heat generating element and the cooling member can be fixed with low stress and in a short time. Therefore, the cured product of the present invention is suitably used as a heat transfer member.

[Reinforcement layer]
The present invention further provides an adhesive tape and an adhesive film having a reinforcing layer. In this aspect, at least one of the above-mentioned pressure-sensitive adhesive tape and pressure-sensitive adhesive film has a structure in which one side of the reinforcing layer is laminated via the thermally conductive cured material layer, or at least two pressure-sensitive adhesive tapes or pressure-sensitive films are provided as the reinforcing layer. The heat conductive cured product layer is laminated on each side of the film. In this aspect, a laminate comprising the thermally conductive cured material layer and the reinforcing layer can be obtained by peeling the base material from the pressure-sensitive adhesive tape having the reinforcing layer and the pressure-sensitive adhesive film. By using the laminate as a heat conductive member as described later, the strength of the heat conductive member can be increased, and a more reliable heating device can be provided.

The reinforcing layer can be selected from metal, plastic, glass cloth, graphite cloth and the like. When the use of a heat conductive adhesive tape is considered, a plastic film is favorable, and among them, a polyimide film excellent in insulation and heat resistance is preferable. The thickness of the polyimide film is preferably 5 μm to 100 μm. If it is thinner than 5 μm, sufficient strength and insulation may not be obtained. When the thickness is 100 μm or more, sufficient strength and insulation can be obtained, but the thermal conductivity of the thermally conductive silicone adhesive tape is reduced.
The method for producing the pressure-sensitive adhesive tape and the pressure-sensitive adhesive film having the reinforcing layer is not particularly limited.

  For example, in the case of a pressure-sensitive adhesive tape and a pressure-sensitive adhesive film having a structure in which a thermally conductive cured material layer is laminated on both sides of the reinforcing layer, first, on one side, The base material of a certain adhesive tape is peeled off, and the heat generating element is fixed to the exposed surface of the thermally conductive cured material layer. Thereafter, the base of the adhesive tape on the other side is peeled off, and the cooling member is fixed to the exposed surface of the thermally conductive cured material layer. Thus, the heat generating element and the cooling member can be interposed in the laminate having the reinforcing layer between the thermally conductive cured material layers. By forming the reinforcing layer as a laminate having the thermally conductive cured material layer, the strength of the thermally conductive member can be increased, and a more reliable heating device such as a semiconductor device can be provided. In the case of an adhesive tape and an adhesive film having a structure in which a thermally conductive cured material layer is laminated on one side of the reinforcing layer, a heating element is provided on the exposed surface of the thermally conductive cured material layer by peeling the base material of the adhesive tape. Fix it. The other surface of the reinforcing layer not having the adhesive tape is in contact with the cooling member. In this aspect, since there is no adhesive layer on one side of the reinforcing layer (the surface where the reinforcing layer and the cooling member are in contact), rework becomes possible.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

（ａ−２）上記式（ａ）で表され、２５℃での動粘度３０,０００ｍｍ^２／ｓを有する、両末端ビニル基（Ｖｉ）含有オルガノポリシロキサン。ビニル基の個数は、該オルガノポリシロキサン１００ｇ当たり０．００３６個である。
（ｂ）熱伝導性充填剤
(ｂ−１)成分 平均粒径１μｍ、粒径４５μｍ以上を有する粒子の含有量が０．１ｗｔ％、且つ、粒径７５μｍ以上を有する粒子の含有量が０．０ｗｔ％の酸化アルミニウム粉末
(ｂ−２)成分 平均粒径１０μｍ、粒径４５μｍ以上を有する粒子の含有量が０．３ｗｔ％、且つ、粒径７５μｍ以上を有する粒子の含有量が０．０ｗｔ％の酸化アルミニウム粉末
（ｃ）下記式で表されるオルガノハイドロジェンシロキサン：

式中、ｍは１６．８（平均重合度）であり、ｋは６．３（平均重合度）である。
（ｄ）付加反応触媒：５％ 塩化白金酸の２−エチルヘキサノール溶液
（ｅ）反応制御剤：エチニルメチリデンカルビノール
（ｆ）シリコーンレジン：実質的に、Ｍｅ_３ＳｉＯ_０．５単位（Ｍ単位）とＳｉＯ_２単位（Ｑ単位）のみからなるシリコーンレジン（Ｍ／Ｑモル比は１．１５）のトルエン溶液（レジン分７０％：粘度３０ｍｍ^２／ｓ）
（ｇ）下記式で表されるジメチルポリシロキサン
（ｇ−１）下記式で表されるジメチルポリシロキサン

（R¹=オクチル基、R²=メチル基、R³=メチル基、a=1,b=1）
（ｇ−２）下記式で表されるジメチルポリシロキサン

式中、ｓは３０（平均重合度）である。 Each component used in the following Examples and Comparative Examples is as follows.
(A) Organopolysiloxane having an alkenyl group (a-1) A vinyl terminal (Vi) -containing organopolysiloxane represented by the following formula (a) and having a kinematic viscosity of 600 mm ² / s at 25 ° C. The number of vinyl groups is 0.015 per 100 g of the organopolysiloxane.

(A-2) A both-end vinyl group (Vi) -containing organopolysiloxane represented by the above formula (a) and having a kinematic viscosity of 30,000 mm ² / s at 25 ° C. The number of vinyl groups is 0.0036 per 100 g of the organopolysiloxane.
(B) thermally conductive filler
(b-1) Component Aluminum oxide powder in which the content of particles having an average particle diameter of 1 μm and a particle diameter of 45 μm or more is 0.1 wt% and the content of particles having a particle diameter of 75 μm or more is 0.0 wt%
(b-2) Component Aluminum oxide powder having an average particle diameter of 10 μm and a content of particles having a particle diameter of 45 μm or more of 0.3 wt% and a content of particles having a particle diameter of 75 μm or more of 0.0 wt% ) Organohydrogensiloxane represented by the following formula:

In the formula, m is 16.8 (average degree of polymerization) and k is 6.3 (average degree of polymerization).
(D) addition reaction catalyst: 5% 2-ethylhexanol solution of chloroplatinic acid (e) reaction control agent: ethynylmethylidenecarbinol (f) silicone resin: substantially _0.5 units of Me ₃ SiO (M units) Solution of silicone resin (M / Q molar ratio is 1.15) consisting only of SiO ₂ unit (Q unit) (70% resin content: viscosity 30 mm ² / s)
(G) Dimethylpolysiloxane represented by the following formula (g-1) Dimethylpolysiloxane represented by the following formula

(R ¹ = octyl group, R ² = methyl group, R ³ = methyl group, a = 1, b = 1)
(G-2) Dimethylpolysiloxane represented by the following formula

In the formula, s is 30 (average degree of polymerization).

[Examples 1 to 6 and Comparative Examples 1 to 5]
The above components were blended in parts by mass shown in Tables 1 and 2, and mixed uniformly to prepare a silicone composition. The mixing was performed using a planetary mixer. An appropriate amount of toluene was added to the obtained silicone composition, and coating was performed on two PET films surface-treated with a fluorine-based mold release agent (manufactured by Shin-Etsu Chemical Co., Ltd .: X-70-201). A comma coater was used for coating. After volatilizing toluene at 80 ° C., curing at 120 ° C. for 5 minutes, an adhesive tape having a 30 μm thick thermally conductive cured product layer, and an adhesive tape having a 50 μm thick thermally conductive cured product layer, I got

※ｆ成分について括弧外の数値はトルエン溶液の質量部であり、括弧内の数値がシリコーンレジンの質量部である。

※ The numerical value without a parenthesis about f ingredient is a mass part of a toluene solution, and the numerical value in a parenthesis is a mass part of silicone resin.

比較例1,2に示すように、熱伝導性充填材の添加量が不十分だと、粘着力は高い値を示すものの、低熱伝導率となる。比較例3に示すように、熱伝導性充填材の添加量が過剰であると、得られた熱伝導性シリコーン粘着テープを転写できず、熱伝導率、粘着力の測定が行えず、実使用を鑑みても製品として成立しない。比較例4、5のようにシリコーンレジンの添加量が少なすぎると、十分な粘着力が得られない。

As shown in Comparative Examples 1 and 2, when the amount of the thermally conductive filler added is insufficient, the adhesive strength is high, but the thermal conductivity is low. As shown in Comparative Example 3, when the addition amount of the thermally conductive filler is excessive, the obtained thermally conductive silicone adhesive tape can not be transferred, and the measurement of the thermal conductivity and the adhesive force can not be performed, and the practical use Even in view of the product does not hold. If the amount of silicone resin added is too small as in Comparative Examples 4 and 5, sufficient adhesive strength cannot be obtained.

  The present invention provides a thermally conductive silicone adhesive tape having a high thermal conductivity of 2.5 W / mK or more and an adhesive strength of 0.1 MPa or more. The tape can fix the heating element at a low pressure and in a short time, and can provide a reliable heating device. Furthermore, the manufacturing efficiency can also be increased. Therefore, the thermally conductive cured product of the present invention can be suitably used as a thermally conductive member interposed between the cooling member and the heating element.

Claims (7)

Curable silicone composition comprising the following components (a) to (g): (a) 100 parts by mass of organopolysiloxane having an alkenyl group,
(B) thermally conductive filler 4000 to 13000 parts by mass,
(C) Organohydrogenpolysiloxane (a) An amount in which the ratio of the number of hydrogen atoms bonded to silicon atoms in the component (c) to the number of alkenyl groups in the component is 0.5 to 3,
(D) Addition reaction catalyst Catalytic amount (e) 10 to 50,000 ppm with respect to the mass of the reaction control agent (a) component
(F) Silicone resin 280 to 600 parts by mass (g) Compound having 1 to 3 alkoxy groups represented by the following general formula (1) or (2) 80 to 300 parts by mass

(Wherein, R ¹ is each independently an alkyl group having 6 to 15 carbon atoms, R ² is each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, and R ³ is mutually independent Is an alkyl group having 1 to 6 carbon atoms, a is an integer of 1 to 3, b is an integer of 0 to 2, provided that a + b is an integer of 1 to 3),

(In the formula, R ⁴ are each independently an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100).   The thermally conductive filler is alumina, the content of particles having an average particle diameter of less than 20 μm, and having a particle diameter of 45 μm or more is 0.5 wt% or less, and the content of particles having a particle diameter of 75 μm or more The curable silicone composition according to claim 1, wherein is 0.1 wt% or less.   A method for heat curing the curable silicone composition according to claim 1 or 2 to obtain a thermally conductive cured product, wherein the cured product has a thermal conductivity of 2.5 W / mK or more. The method according to claim 3, characterized in that a thermally conductive cured product having an adhesive strength such that the adhesive strength between a 100 um thick cured product and an aluminum plate is 0.1 MPa or more is obtained.   The adhesive tape or film which has a sheet-like base material and the layer of the hardened | cured material of the curable silicone composition of any one of Claims 1-2 laminated | stacked on at least 1 surface of this base material.   The pressure-sensitive adhesive tape or film according to claim 5 is laminated on one surface of the reinforcing layer via the cured product layer, or two of the pressure-sensitive adhesive tape or film according to claim 5 are respectively disposed on both surfaces of the reinforcing layer via the cured material layer. The pressure-sensitive adhesive tape or film according to claim 3, which is laminated. The pressure-sensitive adhesive tape or film according to claim 6, wherein the reinforcing layer is a polyimide film.