Composition for thermally conductive silicone adhesive tape and thermally conductive silicone adhesive tape

Abstract

To provide a composition for a thermally conductive silicone adhesive tape that has superior handleability and ensures sufficient adhesive strength, and also exhibits high heat performance.SOLUTION: A composition for a thermally conductive silicone adhesive tape contains the following (a)-(e): (a) a linear or branched organopolysiloxane with two or more alkenyl groups in one molecule: 100 pts.mass; (b) a silver filler: 3,000-7,500 pts.mass; and (c) a three-dimensional networked organopolysiloxane resin including a (c-1) component represented by the formula (1) and a (c-2) component represented by the formula (2): 150-450 pts.mass; (d) an organic silicon compound represented by the formula (3): 1-30 pts.mass; and (e) an organic peroxide: 5-40 pts.mass.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition for a thermally conductive silicone adhesive tape and a thermally conductive silicone adhesive tape. [Background technology]

[0002] Generally, in fields such as electronic component packages and power modules, screws and clips are used to fasten cooling materials and semiconductors. However, fastening methods using screws and clips require many parts and processes, resulting in very poor manufacturing efficiency. In addition, this method prevents the electronic device itself from being made smaller and thinner, and is very disadvantageous in terms of product design. Therefore, in recent years, a method has been developed in which adhesive and bonding properties are imparted to the heat dissipation material placed between the cooling material and the semiconductor, thereby fastening the semiconductor element to the housing.

[0003] Specifically, a method of fixing the housing and the semiconductor element by imparting adhesiveness to a thermally conductive sheet interposed between a cooling member and a semiconductor is conceivable. For example, there is a method of applying an adhesive to both sides of a thermally conductive sheet to make a thermally conductive adhesive sheet. This method can improve workability and reduce the risk of voids being mixed in, but since the adhesive itself does not have thermal conductivity, the thermal conductivity of the sheet is significantly deteriorated. Therefore, for example, thermally conductive adhesive tapes using a thermally conductive filler in the adhesive, as described in Patent Documents 1 and 2, are known. In addition, Patent Document 3 describes a thermally conductive silicone adhesive tape using silicone as a base polymer, which is known to have excellent heat resistance, cold resistance, and durability.

[0004] However, while conventional adhesive tapes are advantageous for rework, they have poor adhesive strength and reliability issues.In addition, compared to liquid and paste compositions, they have a high contact thermal resistance, leaving room for improvement in terms of high thermal conductivity.

[0005] On the other hand, some types of heat-curing heat-dissipating adhesives have high adhesion to heat-dissipating components and can provide high adhesive strength and heat dissipation performance. However, they have issues such as being less workable than sheet-type adhesives, such as the need for a complicated application process, and the risk of voids being introduced.

[0006] Furthermore, in order to accommodate new applications that have been created in recent years, there is an increasing demand for high thermal conductivity and reliability in heat dissipation materials. Silver filler has attracted attention as a thermally conductive filler that can meet such requirements. Silver itself has an extremely high thermal conductivity, and when heated and cured, the fillers partially sinter together to efficiently form heat conduction paths. For this reason, heat dissipation materials with added silver filler are expected to have significantly improved thermal performance.

[0007] On the other hand, it is known that addition-curing silicone compositions using silver fillers have poor curability. Therefore, for example, when used in the above-mentioned addition-curing adhesive, the composition is mounted on electronic component packages or power modules in an insufficiently cured state, making it difficult to achieve both reliability and curability. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2014-34652 A [Patent Document 2] JP 2014-62220 A [Patent Document 3] JP 2008-260798 A Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide a composition for a thermally conductive silicone adhesive tape that is easy to handle, provides sufficient adhesive strength, and has high thermal performance, and to provide a thermally conductive silicone adhesive tape that is easy to handle and can be easily mounted on a heat dissipating component.

Means for Solving the Problem

[0010] In order to solve the above problems, the present invention provides a composition for a thermally conductive silicone adhesive tape, wherein the composition for a thermally conductive silicone adhesive tape contains the following components (a) to (e). (a) Linear or branched organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass (b) Silver filler: 3,000 to 7,500 parts by mass (c) Three-dimensional network organopolysiloxane resin containing the following components (c-1) and (c-2): 150 to 450 parts by mass (c-1): Three-dimensional network organopolysiloxane resin represented by the following average composition formula (1), wherein the amount of alkenyl groups in the molecule is 0.05 to 0.15 mol / 100 g [Chemical Formula] (In formula (1), R 1 is independently a group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, and R 2 is an alkenyl group having 2 to 8 carbon atoms. 0 < a1 ≦ 100, 0 < b1 ≦ 100, 0 ≦ c1 ≦ 100, 0 ≦ d1 ≦ 100, 0 ≦ e1 ≦ 100. However, it is assumed that the range of 0.5 ≦ a1 / (d1 + e1) ≦ 2.0 is satisfied.) (c-2): Three-dimensional network organopolysiloxane resin represented by the following average composition formula (2) [Chemical Formula] (In formula (2), R 1 is the same as in formula (1) above, 0 < a2 ≦ 100, 0 ≦ c2 ≦ 100, 0 ≦ d2 ≦ 100, 0 < e2 ≦ 100. However, it is assumed that the range of 0.7 ≦ a2 / e2 ≦ 2.5 is satisfied.) (d) an organosilicon compound represented by the following general formula (3): 1 to 30 parts by mass [ka] (n is an integer from 1 to 20.) (e) Organic peroxide: 5 to 40 parts by mass

[0011] Such a composition for a thermally conductive silicone adhesive tape can provide a thermally conductive silicone adhesive tape that is easy to handle, has sufficient adhesive strength, and has high thermal performance.

[0012] Moreover, the composition for a thermally conductive silicone adhesive tape preferably further contains, as component (f), 1 to 30 parts by mass of an organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule.

[0013] Such a composition for a thermally conductive silicone adhesive tape exhibits good wettability with the interface of the adherend, thereby enhancing adhesive strength.

[0014] Furthermore, the composition for a thermally conductive silicone adhesive tape preferably contains component (c-1) in an amount of 10 to 60 mass % relative to the total amount of three-dimensional network organopolysiloxane resin (c).

[0015] Such a composition for a thermally conductive silicone adhesive tape can provide particularly good adhesive strength.

[0016] Additionally, the composition for a thermally conductive silicone adhesive tape preferably further contains, as component (g), 1 to 20 parts by mass of one or more selected from the following components (g-1) and (g-2): (g-1) An alkoxysilane compound represented by the following average composition formula (4): [ka] (In formula (4), R 3is an alkyl group having 6 to 15 carbon atoms, and R 4 is an alkyl group having 1 to 5 carbon atoms, and R 5 is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 3, and n is an integer of 0 to 2, with the proviso that m+n is an integer of 1 to 3. (g-2) Dimethylpolysiloxane represented by the following general formula (5): [ka] (In formula (5), R 5 is the same as the above formula (4), and p is an integer of 5 to 100.

[0017] With such a composition for a thermally conductive silicone adhesive tape, it is possible to obtain a composition in which component (b) is uniformly dispersed within the matrix of component (a).

[0018] The (b) silver filler preferably has an average particle size of 0.1 to 50 μm.

[0019] With such a composition for a thermally conductive silicone adhesive tape, a good composition for a thermally conductive silicone adhesive tape can be obtained.

[0020] Furthermore, the composition for a thermally conductive silicone adhesive tape is preferably one that, when cured, has a thermal conductivity of 15.0 W / mK or greater.

[0021] With such a composition for a thermally conductive silicone adhesive tape, it is possible to obtain a composition for a thermally conductive silicone adhesive tape having good thermal conductivity.

[0022] The present invention also provides a thermally conductive silicone adhesive tape having a substrate on one or both sides of a thermally conductive adhesive layer, the thermally conductive adhesive layer being made from the composition for thermally conductive silicone adhesive tapes.

[0023] Such a thermally conductive silicone adhesive tape is preferable because it has excellent handleability.

[0024] The substrate preferably has a cured coating of fluorine-modified silicone on one or both sides.

[0025] Such a thermally conductive silicone adhesive tape is preferable because it is particularly easy to handle. Effect of the Invention

[0026] The composition for thermally conductive silicone adhesive tape of the present invention provides very good thermal conductivity between the heat generating element and the heat dissipating member, and is free of the curing inhibition seen in addition vulcanization systems, and exhibits a favorable adhesive strength, enabling strong fixation between the members and providing excellent reliability. Furthermore, the thermally conductive silicone adhesive tape of the present invention is easy to handle and can be easily mounted on the heat dissipating member.

[0027] Therefore, the thermally conductive silicone adhesive tape composition of the present invention is extremely effective as a thermally conductive member that is interposed between a heat-generating element and a heat-dissipating member, transferring heat generated by the heat-generating element to the heat-dissipating member and fixing the element in place. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] As described above, there has been a need for the development of a composition for a thermally conductive silicone adhesive tape that is easy to handle, provides sufficient adhesive strength, and has high thermal performance.

[0029] As a result of extensive research into achieving the above-mentioned object, the inventors discovered that by specifying the composition of the silicone resin and the amount of silver filler in a peroxide-curing type composition for a thermally conductive silicone adhesive tape, it is possible to obtain a composition for a thermally conductive silicone adhesive tape and a thermally conductive silicone adhesive tape which are easy to handle, have good adhesive strength to a heat dissipation component, and have excellent thermal conductivity, and this led to the completion of the present invention.

[0030] That is, the present invention provides: A composition for a thermally conductive silicone adhesive tape, The composition for a thermally conductive silicone adhesive tape contains the following components (a) to (e) and is a composition for a thermally conductive silicone adhesive tape. (a) Linear or branched organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass (b) Silver filler: 3,000 to 7,500 parts by mass (c) Three-dimensional network organopolysiloxane resin containing the following components (c-1) and (c-2): 150 to 450 parts by mass (c-1): Three-dimensional network organopolysiloxane resin represented by the following average composition formula (1) and having an alkenyl group content of 0.05 to 0.15 mol / 100 g in the molecule

Chemical formula

Chemical formula

Chemical formula

[0031] Each component will be described in detail below, but the present invention is not limited to these.

[0032] (a) A linear or branched organopolysiloxane having two or more alkenyl groups in one molecule. Component (a) is a linear or branched organopolysiloxane having two or more alkenyl groups in one molecule, and may be used alone or in appropriate combination of two or more. Specific examples of component (a) include those represented by the following formulas (6) to (8). [ka] (In the formula, R 6 are independently a group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, and X is an alkenyl group having 2 to 8 carbon atoms. d and e are each 0 or a positive number of 1 or more, f is a positive number of 1 or more, and g is a positive number of 2 or more. The bonding order of the siloxane units bracketed by d to g may be in a block or random order.

[0033] R 6Examples of the alkyl group include alkyl groups having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups having 5 to 10 carbon atoms, preferably 5 to 7 carbon atoms, such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups having 6 to 10 carbon atoms, preferably 6 to 8 carbon atoms, such as phenyl, tolyl, xylyl, naphthyl, and biphenylyl; and aralkyl groups having 7 to 10 carbon atoms, preferably 7 to 9 carbon atoms, such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl. In addition, some of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted with halogen atoms. Among these, preferred are methyl, ethyl, propyl, 3,3,3-trifluoropropyl, and phenyl.

[0034] Also, R 6 may all be the same or different. 6 Unless special properties such as solvent resistance are required, it is preferred that all of the groups in the alkyl group be methyl in terms of cost, availability, chemical stability, environmental impact, etc.

[0035] The alkenyl group for X is preferably an alkenyl group having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. Examples include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and the like, and among these, a lower alkenyl group such as a vinyl group or an allyl group is preferred, and a vinyl group is more preferred.

[0036] d is a positive number of 0 or 1 or more, preferably a positive number of 10≦d≦10,000, more preferably a positive number of 50≦d≦2,000, and even more preferably a positive number of 100≦d≦1,000.

[0037] The letter e is a positive number of 0 or 1 or more, preferably 0≦e / (d+e)≦0.5, and more preferably 0≦e / (d+e)≦0.1.

[0038] f is a positive number of 1 or more, and 0 < f / (d + f) ≤ 0.5 is preferable, and 0 < f / (d + f) ≤ 0.1 is more preferable.

[0039] g is a positive number of 2 or more, and 0 < g / (d + g) ≤ 0.5 is preferable, and 0 < g / (d + g) ≤ 0.1 is more preferable.

[0040] The component (a) may be in an oil form or a gum form, and may be used alone or in combination of a plurality of those having different viscosities. Its average degree of polymerization is preferably 10 to 5,000, and more preferably 100 to 2,000.

[0041] The degree of polymerization refers to the number average degree of polymerization determined as a polystyrene equivalent value in gel permeation chromatography (GPC) analysis using toluene, tetrahydrofuran (THF), etc. as a developing solvent (hereinafter the same).

[0042] (b) Silver filler The component (b) is a silver filler serving as a thermal conductivity filler. The production method of the silver filler is not particularly limited, and examples thereof include an electrolysis method, a heat treatment method, an atomization method, a reduction method, etc. Further, its shape is not particularly limited, such as flake shape, spherical shape, granular shape, irregular shape, needle shape, etc.

[0043] The component (b) preferably has an average particle size of 0.1 to 50 μm, preferably 0.5 to 40 μm, and more preferably 1 to 30 μm. The thermal conductivity filler may be used alone or in combination of a plurality of types. Further, two or more types of particles having different average particle sizes may be used. In the present invention, the average particle size is the volume average particle size and is a measured value by a microtrack particle size distribution measuring device MT3300EX (Nikkiso Co., Ltd.).

[0044] The component (b) may be subjected to various known surface treatments. Specifically, for example, coupling agent treatments such as silane-based and titanate-based, and plasma treatment, etc. are included.

[0045] (b) The compounding quantity of the component is 3,000 to 7,500 parts by mass, preferably 3,500 to 6,500 parts by mass, and more preferably 4,000 to 6,000 parts by mass with respect to 100 parts by mass of the component (a).

[0046] When the compounding quantity of the component (b) is more than 7,500 parts by mass, the thermal conductive adhesive layer becomes brittle and the workability deteriorates. On the other hand, when it is less than 3,000 parts by mass, the desired thermal conductivity cannot be obtained. (b) The component can be used alone or in combination of two or more kinds.

[0047] (c) Three-dimensional network organopolysiloxane resin The three-dimensional network organopolysiloxane resin as the component (c) functions to impart cohesion to the composition for the thermal conductive silicone adhesive tape and to give workability, and to obtain good adhesive strength in the adhesive layer after curing.

[0048] The component (c) is composed of a three-dimensional network organopolysiloxane resin containing the following component (c-1) and component (c-2). (c-1): A three-dimensional network organopolysiloxane resin represented by the following average composition formula (1) and having an alkenyl group amount in the molecule of 0.05 to 0.15 mol / 100 g [Chemical formula] (In formula (1), R 1 is independently a group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, and R 2 is an alkenyl group having 2 to 8 carbon atoms. 0 < a1 ≤ 100, 0 < b1 ≤ 100, 0 ≤ c1 ≤ 100, 0 ≤ d1 ≤ 100, 0 ≤ e1 ≤ 100. However, it is assumed that the range of 0.5 ≤ a1 / (d1 + e1) ≤ 2.0 is satisfied.) (c-2): A three-dimensional network organopolysiloxane resin represented by the following average composition formula (2) [Chemical formula] (In formula (2), R 1 is the same as in the above formula (1), 0 < a2 ≤ 100, 0 ≤ c2 ≤ 100, 0 ≤ d2 ≤ 100, and 0 < e2 ≤ 100. However, it should satisfy the range of 0.7 ≤ a2 / e2 ≤ 2.5.)

[0049] (c-1) Component (The component (c-1) is a three-dimensional network organopolysiloxane resin represented by the following average composition formula (1), and the alkenyl group in the molecule is 0.05 to 0.15 mol / 100 g.)

Chemical formula

[0050] In the above formula, R 1 is a group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms. Specifically, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group; halogen-substituted alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc. are mentioned. In particular, a methyl group is preferred.)

[0051] R 2 is an alkenyl group having 2 to 8 carbon atoms. Specifically, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, cyclohexenyl group, heptenyl group, etc. are mentioned. In particular, a vinyl group is preferred.)

[0052] In the above formula, 0 < a1 ≤ 100, preferably 1 ≤ a1 ≤ 50. Also, 0 < b1 ≤ 100, preferably 1 ≤ b1 ≤ 50. Also, 0 ≤ c1 ≤ 100, preferably 0 ≤ c1 ≤ 50. Also, 0 ≤ d1 ≤ 100, preferably 0 ≤ d1 ≤ 50. And 0 ≤ e1 ≤ 100, preferably 1 ≤ e1 ≤ 50. However, it should satisfy the range of 0.5 ≤ a1 / (d1 + e1) ≤ 2.0, preferably the range of 0.6 ≤ a1 / (d1 + e1) ≤ 1.8, and more preferably the range of 0.7 ≤ a1 / (d1 + e1) ≤ 1.5.

[0053] When the above ratio is less than 0.5, it becomes difficult to highly fill the silver filler as the component (b), and the thermal conductivity of the composition for the thermally conductive silicone adhesive tape decreases. Or when the above ratio exceeds 2.0, the cohesive force of the composition for the thermally conductive silicone adhesive tape decreases, and the workability decreases.

[0054] Also, for the component (c-1), the alkenyl group in the molecule is 0.05 to 0.15 mol / 100 g, preferably 0.06 to 0.14 mol / 100 g, and more preferably 0.07 to 0.12 mol / 100 g. When the alkenyl group in the molecule is less than 0.05 mol / 100 g, it is difficult to obtain sufficient adhesive strength, so it is not preferable. When it is more than 0.15 mol / 100 g, the composition for the thermally conductive silicone adhesive tape becomes hard and brittle, and the workability decreases, so it is not preferable.

[0055] (c-2) Component (The component (c-2) is a three-dimensional network organopolysiloxane resin represented by the following average composition formula (2).

Chemical formula

[0056] In the formula, R 1is the same as the above formula (1), where 0 < a2 ≤ 100, preferably 1 ≤ a2 ≤ 50. Also, 0 ≤ c2 ≤ 100, preferably 0 ≤ c2 ≤ 50. Further, 0 ≤ d2 ≤ 100, preferably 0 ≤ d2 ≤ 50. And 0 < e2 ≤ 100, preferably 1 ≤ e2 ≤ 50. However, it should satisfy the range of 0.7 ≤ a2 / e2 ≤ 2.5, preferably the range of 0.8 ≤ a2 / e2 ≤ 2.2, and more preferably the range of 0.9 ≤ a2 / e2 ≤ 2.0.

[0057] When the ratio of a2 / e2 is less than 0.7, it becomes difficult to highly fill the silver filler which is the component (b), and the thermal conductivity of the silicone adhesive tape composition decreases. Or when the ratio exceeds 2.5, the cohesive force of the silicone adhesive tape composition decreases, and the desired adhesive strength cannot be obtained.

[0058] In addition, R 1 is preferably all methyl groups for reasons such as cost, its availability, chemical stability, and environmental load, unless special properties such as solvent resistance are required.

[0059] The three-dimensional network organopolysiloxane resin which is the component (c) can be used as a toluene solution of 50 - 70 mass% in the case of being solid. The kinematic viscosity in that case is 10 - 500 mm 2 / s, preferably 100 - 250 mm 2 / s. The kinematic viscosity is the value at 25 °C measured by a Cannon-Fenske viscometer described in JIS Z8803:2011.

[0060] How to measure the ratio of M-units, T-units, and Q-units In the present invention, the trifunctional R of the organopolysiloxane resin having a three-dimensional network (resin-like) structure 1 SiO 3 / 2 unit (T unit) and the tetrafunctional SiO 4 / 2 unit (Q unit), either or both of the branched-chain siloxane units, and the monofunctional R 1 3SiO 1 / 2The ratio of the unit (M unit), i.e., the value of a1 / (d1+e1) in the component (c-1) and the value of a2 / e2 in the component (c-2) are 29 It can be determined by Si-NMR.

[0061] 29 There are no particular limitations on the method for preparing a sample for Si-NMR, but for example, the measurement can be performed by dissolving 1 part by mass of organopolysiloxane resin in 3 parts by mass of deuterated chloroform.

[0062] The amount of the three-dimensional network organopolysiloxane resin (c) is 150 to 450 parts by mass, preferably 200 to 350 parts by mass, and more preferably 250 to 300 parts by mass, per 100 parts by mass of the component (a). If the amount of the component (c) added is less than 150 parts by mass, the thermally conductive adhesive layer cannot obtain the desired adhesive strength. If it exceeds 450 parts by mass, the composition for the thermally conductive silicone adhesive tape becomes brittle and lacks flexibility, making it difficult to work with.

[0063] Furthermore, component (c) itself is a solid or viscous liquid at room temperature, and it can also be used dissolved in a solvent. In that case, the amount added to the composition for thermally conductive silicone adhesive tape can be adjusted so that the resin content excluding the solvent content falls within the above range.

[0064] The three-dimensional network organopolysiloxane resin which is component (c) of the present invention is characterized by being formed by combining the above-mentioned components (c-1) and (c-2). In this case, the amount of the (c-1) component is preferably 10 to 60 mass % relative to the total amount of the (c) component, and more preferably 15 to 50 mass %. When the ratio of the (c-1) component is in this range, particularly good adhesive strength can be obtained.

[0065] (d) Organosilicon compounds Component (d) is an organosilicon compound represented by the following general formula (3), which acts as an adhesive component to contribute to improving wettability with the adherend. [ka] (n is an integer from 1 to 20.)

[0066] Furthermore, as a result of extensive research conducted by the inventors of the present invention, it was found that component (d) also has the effect of assisting the sintering of silver in a peroxide vulcanization system and effectively improving thermal conductivity.

[0067] The component (d) may be used alone or in appropriate combination of two or more. The component (d) is added so that the cured product of the present invention has good thermal conductivity and adhesiveness. From the viewpoint of adhesiveness and thermal conductivity, n is an integer of 1 to 20, and preferably 4 to 15.

[0068] The amount of component (d) is 1 to 30 parts by mass, preferably 2 to 25 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of component (a). If the amount of component (d) added is outside this range, the desired adhesiveness and thermal conductivity cannot be obtained.

[0069] (e) Organic peroxide The (e) component is an organic peroxide that decomposes under certain conditions to generate free radicals, and functions to promote the curing of the thermally conductive adhesive layer at high temperatures and to increase the adhesive strength. The organic peroxide may be a conventionally known one, and is not particularly limited, and may be used alone or in appropriate combination of two or more. For example, peroxyketals such as 1,1-di(t-butylperoxy)cyclohexane and 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, hydroperoxides such as p-menthane hydroperoxide and diisopropylbenzene hydroperoxide, dialkyl peroxides such as dicumyl peroxide and t-butylcumyl peroxide, diacyl peroxides such as dibenzoyl peroxide and disuccinic acid peroxide, peroxyesters such as t-butyl peroxyacetate and t-butyl peroxybenzoate, and peroxydicarbonates such as diisopropyl peroxydicarbonate. In particular, the use of peroxyketals, hydroperoxides, dialkyl peroxides, and peroxyesters, which have relatively high decomposition temperatures, is preferred from the viewpoint of ease of handling and storage. These organic peroxides may be used after being diluted with any organic solvent, hydrocarbon, liquid paraffin, inert solid, or the like.

[0070] The amount of the (e) component is 5 to 40 parts by mass, preferably 10 to 35 parts by mass, based on 100 parts by mass of the (a) component. If the amount of the (e) component is less than 5 parts by mass, the thermally conductive adhesive layer will not be cured sufficiently when cured after being fixed to the heat dissipation member, resulting in a decrease in adhesive strength. If the amount of the (e) component is more than 40 parts by mass, the effect of decomposition residues will be large when cured, resulting in a decrease in adhesive strength.

[0071] The present invention relates to a composition for a thermally conductive silicone adhesive tape that essentially contains the above-mentioned components (a) to (e), but the following components may also be added to this composition as desired.

[0072] (f) Organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule The above-mentioned composition for a thermally conductive silicone adhesive tape may further contain (f) an organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule.

[0073] The component (f) is an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms (i.e., hydrosilyl groups) in one molecule, and functions to exhibit good wettability with the interface of the adherend and to increase adhesive strength. The organohydrogenpolysiloxane may be a known compound, but it is preferable that the organohydrogenpolysiloxane does not substantially contain hydroxyl groups bonded to silicon atoms (i.e., silanol groups) in the molecule. The organohydrogenpolysiloxane may be used alone or in combination of two or more types.

[0074] The organohydrogenpolysiloxane can be represented by the following average composition formula (9). [ka] In the above formula (9), R 6 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms. However, it does not include an aliphatic unsaturated group such as an alkenyl group. Examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups, aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups, and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups. Among them, an alkyl group or an aryl group is preferred, and a methyl group is more preferred. In addition, r is a positive number of 0.7 to 2.1, preferably a positive number of 1.0 to 2.0. s is a positive number of 0.001 to 1.0, preferably a positive number of 0.01 to 1.0. Furthermore, r+s is a number that satisfies the range of 0.8 to 3.0, and preferably a number that satisfies the range of 1.5 to 2.5.

[0075] The organohydrogenpolysiloxane has 2 to 200, preferably 3 to 100, and more preferably 4 to 50 hydrosilyl groups in one molecule. The hydrosilyl groups may be located at either the terminal or the middle of the molecular chain, or may be located at both. The molecular structure of the organohydrogenpolysiloxane may be any of a linear, cyclic, branched, and three-dimensional network structure. The number of silicon atoms (degree of polymerization) in one molecule is usually 2 to 300, preferably 3 to 150, and more preferably 4 to 100. The degree of polymerization can be determined, for example, as the number average degree of polymerization (number average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) analysis using toluene as a developing solvent.

[0076] Examples of the organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris(hydrogendimethylsiloxy)methylsilane, tris(hydrogendimethylsiloxy)phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, methylhydrogenpolysiloxane capped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane copolymer capped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer capped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane-diphenylsiloxane copolymer capped with trimethylsiloxy groups at both molecular chain ends, and dimethylsiloxane-methylhydrogensiloxane-diphenylsiloxane capped with trimethylsiloxy groups at both molecular chain ends. dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane at both molecular ends, dimethylpolysiloxane at both molecular ends, dimethylsiloxane-methylhydrogensiloxane copolymer at both molecular ends, dimethylsiloxane-methylphenylsiloxane copolymer at both molecular ends, dimethylsiloxane-diphenylsiloxane copolymer at both molecular ends, methylphenylpolysiloxane at both molecular ends, and diphenylpolysiloxane at both molecular ends, in which some or all of the methyl groups have been replaced by other alkyl groups such as ethyl or propyl groups, and compounds of the formula: R 7 3SiO 1 / 2 (R in the formula 7 is a monovalent hydrocarbon group other than an alkenyl group, and the R 1 The siloxane unit represented by the formula: R 7 2HSiO 1 / 2 Siloxane units represented by the formula: SiO 4 / 2 Organosiloxane copolymers consisting of siloxane units represented by the formula: R 7 2HSiO 1 / 2Siloxane units represented by the formula: SiO 4 / 2 Organosiloxane copolymers consisting of siloxane units represented by the formula: R 7 HSiO 2 / 2 Siloxane units represented by the formula: R 7 SiO 3 / 2 Siloxane unit or formula: HSiO 3 / 2 Examples of the organosiloxane copolymer include those having siloxane units represented by the following formula: These organohydrogenpolysiloxanes may be used in combination of two or more kinds.

[0077] The blending amount of the (f) component is 1 to 30 parts by mass, preferably 5 to 20 parts by mass, per 100 parts by mass of the (a) component. When the amount of the (f) component is 1 part by mass or more, the wettability to the adherend is improved, and the adhesive strength can be increased. When the amount is 30 parts by mass or less, the adhesive layer does not become brittle, and the adhesive strength is good.

[0078] (g) Surface treatment agent The composition for thermally conductive silicone adhesive tape may further contain (g) a surface treatment agent. The (g) component functions to uniformly disperse (b) silver filler in a matrix consisting of (a) an organopolysiloxane having at least two alkenyl groups per molecule during preparation of the composition. The (g) component is at least one selected from an alkoxysilane compound represented by the following (g-1) component and a dimethylpolysiloxane containing a trialkoxy group at one end of the molecular chain represented by the following (g-2). That is, the (g-1) component and the (g-2) component may be used alone or in combination.

[0079] (g-1) An alkoxysilane compound represented by the following average composition formula (4): [ka] (In formula (4), R 3 is an alkyl group having 6 to 15 carbon atoms, and R 4 is an alkyl group having 1 to 5 carbon atoms, and R 5is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 3, and n is an integer of 0 to 2, with the proviso that m+n is an integer of 1 to 3. (g-2) Dimethylpolysiloxane represented by the following general formula (5): [ka] (In formula (5), R 5 is the same as the above formula (4), and p is an integer of 5 to 100.

[0080] In the above formula (4), R 3 Examples of the alkyl group represented by R include a hexyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, and a tetradecyl group. 3 When the number of carbon atoms in the alkyl group represented by the formula (I) is in the range of 6 to 15, the wettability of the silver filler, which is component (b) described above, is sufficiently improved, handling is good, and the composition for thermally conductive silicone adhesive tape has good properties.

[0081] R 4 is an alkyl group having 1 to 5 carbon atoms, preferably having 1 to 3 carbon atoms, and particularly preferably a methyl group.

[0082] R 5 is an alkyl group having 1 to 6 carbon atoms, and preferably an alkyl group having 1 to 4 carbon atoms. Examples include a methyl group, an ethyl group, a propyl group, and a butyl group. A methyl group is more preferred.

[0083] The amount of the component (g) is 1 to 20 parts by mass, and preferably 5 to 15 parts by mass, per 100 parts by mass of the component (a).

[0084] When the amount of component (g) added is 1 part by mass or more, component (b) can be uniformly filled into component (a), and when the amount is 20 parts by mass or less, the adhesive strength of the thermally conductive adhesive layer is not reduced.

[0085] [Other additives] In addition to these optional components, it is possible to add pigments and dyes for coloring, flame retardants, and various other additives to improve functionality.

[0086] [Composition for thermally conductive silicone adhesive tape] The composition for thermally conductive silicone adhesive tape can be prepared by uniformly mixing the above-mentioned components (a) to (e) and, optionally, components (f) and (g), as well as other components. The mixing method may be a conventionally known method. Preferably, components (a), (b), and (c) are mixed with optional component (g), and then components (d), (e), and optional component (f) are mixed.

[0087] [Thermal conductive silicone adhesive tape] The thermally conductive silicone adhesive tape composition is applied to a substrate described below in the form of a thin film tape, molded, and dried to obtain the thermally conductive silicone adhesive tape of the present invention. The drying conditions are 60 to 100°C for 5 to 20 minutes, preferably 70 to 90°C for 5 to 15 minutes. If the drying conditions are within the above range, the thermal conductivity is not reduced due to residual solvent, and the curing reaction of the thermally conductive silicone adhesive tape composition does not progress, so that the thermally conductive adhesive layer after drying can be adhered to the heat dissipation member. The thermally conductive adhesive layer of the present invention is made of the thermally conductive silicone adhesive tape composition in an uncured state, and when mounted between the heat dissipation member and the heat generating member, it is subjected to a heat curing treatment to firmly bond the two.

[0088] The thickness of the thermally conductive adhesive layer of the present invention is preferably 50 to 300 μm, more preferably 75 to 250 μm. If the thickness of the adhesive layer is 50 μm or more, the tape is easy to handle and the adhesive strength does not decrease. On the other hand, if the thickness of the adhesive layer is 300 μm or less, the desired thermal conductivity is obtained. In addition, when coating and molding, it is also possible to add a solvent such as toluene or xylene to the composition for thermally conductive silicone adhesive tape to adjust the viscosity.

[0089] The thermally conductive silicone adhesive tape of the present invention can have a substrate surface-treated with a release agent as a separator film. That is, one or both sides of the thermally conductive adhesive layer made of a composition for thermally conductive silicone adhesive tape may be protected with a release-treated film. By laminating a separator film on the adhesive surface, handling such as transportation and cutting to a fixed length can be made easier. In this case, it is also possible to adjust the peeling force of the separator film by changing the amount and type of release agent and the material of the film.

[0090] The separator film is preferably a polyethylene laminated paper or a PET film, which is release-treated on one or both sides with a cured film of a fluorine-modified silicone having a fluorine substituent, including a perfluoroalkyl group or a perfluoropolyether group, bonded to the main chain. The perfluoropolyether group can be represented by the following formulas (10) to (12). [ka] (p is 1 to 5, and q is 3 to 10)

[0091] Examples of commercially available fluorine-modified silicones that can be used include X-70-201, X-70-258, and X-41-3035 manufactured by Shin-Etsu Chemical Co., Ltd. Methods for molding onto a substrate include coating a liquid material onto the substrate using a bar coater, knife coater, comma coater, spin coater, or the like, but are not limited to the methods described above.

[0092] The thermally conductive silicone adhesive tape of the present invention, although in the form of a thin tape or sheet, can be easily positioned in the desired location, and exhibits excellent thermal conductivity properties after heat curing treatment. Furthermore, by having the separator film described above, it is possible to interpose the tape between a cooling member and a heat-generating electronic component or a heat-dissipating member by peeling off one separator film and then attaching the tape to a heat-generating electronic component or a heat-dissipating member, and then peeling off the remaining separator film and attaching the tape to a cooling member or the like.

[0093] Furthermore, by carrying out a heat treatment after mounting, the curing of the composition for thermally conductive silicone adhesive tape and partial sintering of the silver filler proceed, resulting in good thermal conductivity and adhesion between the members, and enabling strong fixation. The heat treatment after mounting is carried out at 130°C to 190°C for 20 minutes to 90 minutes, preferably at 150°C to 170°C for 30 minutes to 60 minutes, and the pressure during heating is not particularly limited, but is preferably 20 to 200 psi, more preferably 40 to 150 psi, in order to promote sintering of the silver filler. The thermal conductivity of the cured product obtained by curing the composition for thermally conductive silicone adhesive tape as described above is preferably 15.0 W / mK or more, preferably 30.0 W / mK or more, more preferably 40.0 W / mK or more. EXAMPLES

[0094] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0095] The components (a) to (g) constituting the composition for thermally conductive silicone adhesive tape used in the following Examples and Comparative Examples are as follows.

[0096] (a) Ingredients: Dimethylpolysiloxane oil with an average degree of polymerization of 450 and containing vinyl groups at both ends

[0097] (b) Ingredients: (b-1) Spherical silver filler having a volume average particle size of 1 μm (b-2) Flake-shaped silver filler having a volume average particle size of 3 μm (b-3) Flake-shaped silver filler having a volume average particle size of 10 μm

[0098] (c) Ingredients: (c-1) Component 0.08 mol / 100 g of alkenyl groups are bonded only to D units, the ratio of M units to T units and Q units is 0.9, and R 1 = methyl group, R2 = vinyl group, a1 = 1.8, b1 = 1.0, c1 = 0, d1 = 1.0, e1 = 1.0. A toluene solution of silicone resin (50% by mass, kinetic viscosity 10 mm 2 / s) (c-2) Component M / Q (molar ratio)=1.2, all of the substituents bonded to silicon atoms of the M units are methyl groups, and R 1 = methyl group, a2 = 1.2, c2 = 0, d2 = 0, e2 = 1.0. A toluene solution of silicone resin (60% by mass, kinetic viscosity 8 mm 2 / s)

[0099] (d) Component: Octenyltrimethoxysilane

[0100] (e) Component: 2,5-dimethyl-2,5-di(t-butylperoxy)hexane

[0101] Component (f): Organohydrogenpolysiloxane represented by the following formula: [ka] (R of the average composition formula (9) 6 = methyl group, r = 1.4, s = 0.8)

[0102] (g-1) Component: Decyltrimethoxysilane Component (g-2): Dimethylpolysiloxane having a trimethoxysilyl group at one end, represented by the following formula: [ka]

[0103] The above components (a), (b), (c), and (g) were placed in a Shinagawa universal mixer in the amounts shown in Tables 1 and 2 below and mixed for 60 minutes. Next, components (d), (e), and (f) were added in the amounts shown in Tables 1 and 2 below and mixed uniformly to obtain a uniform composition for thermally conductive silicone adhesive tape.

[0104] [Making of thermally conductive silicone adhesive tape] To the composition for thermally conductive silicone adhesive tape obtained above, an appropriate amount of toluene was added. The toluene solution was applied onto a fluorine-treated PET film (separator film), and the toluene was evaporated at 80°C for 15 minutes to form a thermally conductive silicone adhesive tape having a size of 200 x 300 mm and a thickness of 150 μm. Note that this thickness is the thickness of only the composition for thermally conductive silicone adhesive tape, and does not include the thickness of the separator film. Note that the surface treatment of the fluorine-treated PET film (separator film) was performed using an addition curing type fluorine-modified silicone release agent (product name: X-41-3035, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0105] [Evaluation method] (1) Handling: When the adhesive layer surface of the thermally conductive silicone adhesive tape was applied to a heat dissipation component (aluminum heat sink), an evaluation was performed to see whether a desired degree of adhesion could be obtained.

[0106] The separator film on one side was peeled off, the adhesive layer surface was attached to an aluminum heat sink, and when the separator film on the other side was peeled off, the adhesive layer or composite was evaluated as to whether it was fixed without slipping from the heat sink. Those that were fixed without slipping were marked with ○, and those that were misaligned were marked with × in the table. The following evaluation was not performed on those that were rated × for handling.

[0107] (2) Thermal conductivity: The thermally conductive silicone adhesive tape with the separator films on both sides removed was sandwiched between aluminum plates and evenly pressed. It was then heated and cured at 150°C / 100psi x 1hr using a dryer, and the thermal resistance was measured using the laser flash method. The effective thermal conductivity was calculated from the relationship between thickness and thermal resistance using the following formula. Thermal conductivity (W / m K) = thickness (μm) / thermal resistance (mm 2 K / W)

[0108] (3) Shear adhesive strength (adhesive force) to aluminum: The thermally conductive adhesive layer or thermally conductive composite was sandwiched between 10 x 10 mm square aluminum plates, uniformly pressed, and then heated and cured in a dryer at 150°C / 100 psi x 1 hr. The peel shear stress of the obtained test pieces was measured at room temperature using a Nordson 4000Plus bond tester.

[0109] [Table 1]

[0110] [Table 2]

[0111] In Examples 1 to 11, the obtained compositions were excellent in transferability and handling properties, and also had excellent thermal conductivity and adhesive strength after thermocompression bonding.

[0112] In Comparative Example 1, the amount of the silver filler as component (b) was less than 3,000 parts by mass per 100 parts by mass of component (a), so that the desired thermal conductivity could not be obtained.

[0113] In Comparative Example 2, the amount of silver filler (b) was more than 7,500 parts by mass per 100 parts by mass of component (a), so the thermally conductive adhesive layer became brittle and transfer was difficult.

[0114] In Comparative Example 3, the silicone resin as component (c) was less than 150 parts by mass per 100 parts by mass of component (a), so the desired adhesive strength could not be obtained.

[0115] In Comparative Example 4, the silicone resin as component (c) was greater than 450 parts by mass per 100 parts by mass of component (a), so the composition for a thermally conductive silicone adhesive tape lacked flexibility and transferability was reduced.

[0116] In Comparative Examples 5 and 6, since the organosiloxane as the component (d) was not in the range of 1 to 30 parts by mass, the desired adhesive strength and thermal conductivity could not be obtained.

[0117] In Comparative Examples 7 and 8, since the peroxide as the component (e) was not in the range of 5 to 40 parts by mass, the desired adhesive strength and thermal conductivity could not be obtained.

[0118] As described above, it has been shown that the present invention provides a composition for a thermally conductive silicone adhesive tape that is easy to handle, has excellent transferability to members, and has good adhesive strength and thermal conductivity.

[0119] This specification includes the following aspects. [1]: A composition for a thermally conductive silicone adhesive tape, wherein the composition for a thermally conductive silicone adhesive tape contains the following components (a) to (e). (a) A linear or branched organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass (b) Silver filler: 3,000 to 7,500 parts by mass (c) A three-dimensional network organopolysiloxane resin containing the following components (c-1) and (c-2): 150 to 450 parts by mass (c-1): A three-dimensional network organopolysiloxane resin represented by the following average composition formula (1) and having an alkenyl group content in the molecule of 0.05 to 0.15 mol / 100 g

Chemical formula

[0120] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A composition for a thermally conductive silicone adhesive tape, comprising: The composition for a thermally conductive silicone adhesive tape is characterized in that it contains the following components (a) to (e): (a) Linear or branched organopolysiloxane having two or more alkenyl groups in one molecule: 100 parts by mass (b) Silver filler: 3,000 to 7,500 parts by mass (c) a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (c-2): 150 to 450 parts by mass: (c-1): A three-dimensional network organopolysiloxane resin represented by the following average composition formula (1) and having an alkenyl group content in the molecule of 0.05 to 0.15 mol / 100 g. 【Chemistry 1】 (In formula (1), R １ are independently selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms; R ２ is an alkenyl group having 2 to 8 carbon atoms. 0<a1≦100, 0<b1≦100, 0≦c1≦100, 0≦d1≦100, and 0≦e1≦100, provided that the range of 0.5≦a1 / (d1+e1)≦2.0 is satisfied. (c-2): A three-dimensional network organopolysiloxane resin represented by the following average composition formula (2): 【Chemistry 2】 (In formula (2), R １ is the same as the above formula (1), 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100. However, the range of 0.7≦a2 / e2≦2.5 is satisfied.) (d) an organosilicon compound represented by the following general formula (3): 1 to 30 parts by mass 【Chemistry 3】 (n is an integer from 1 to 20.) (e) Organic peroxide: 5 to 40 parts by mass

2. The composition for a thermally conductive silicone adhesive tape according to claim 1, characterized in that it further contains, as component (f), 1 to 30 parts by mass of an organohydrogenpolysiloxane having two or more hydrosilyl groups per molecule.

3. The composition for thermally conductive silicone adhesive tape according to claim 1, characterized in that the ratio of component (c-1) to the total amount of the three-dimensional network organopolysiloxane resin (c) is 10 to 60 mass %.

4. The composition for a thermally conductive silicone adhesive tape according to claim 1, characterized in that it further contains, as component (g), 1 to 20 parts by mass of one or more selected from the following components (g-1) and (g-2): (g-1) An alkoxysilane compound represented by the following average composition formula (4): 【Chemistry 4】 (In formula (4), R ３ is an alkyl group having 6 to 15 carbon atoms; R ４ is an alkyl group having 1 to 5 carbon atoms; R ５ is an alkyl group having 1 to 6 carbon atoms, m is an integer of 1 to 3, and n is an integer of 0 to 2, provided that m+n is an integer of 1 to 3. (g-2) Dimethylpolysiloxane represented by the following general formula (5): 【Chemistry 5】 (In formula (5), R ５ is the same as the above formula (4), and p is an integer of 5 to 100.

5. 2. The composition for a thermally conductive silicone adhesive tape according to claim 1, wherein the silver filler (b) has an average particle size of 0.1 to 50 μm.

6. 6. A composition for a thermally conductive silicone adhesive tape according to claim 1, wherein the composition for a thermally conductive silicone adhesive tape has a thermal conductivity of 15.0 W / mK or more after curing.

7. A thermally conductive silicone adhesive tape having a substrate on one or both sides of a thermally conductive adhesive layer, 6. A thermally conductive silicone adhesive tape, wherein the thermally conductive adhesive layer is made of the composition for thermally conductive silicone adhesive tape according to claim 1.

8. 8. The thermally conductive silicone adhesive tape according to claim 7, wherein the substrate has a cured coating of fluorine-modified silicone on one or both sides.

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