JP7661275B2 - Composition for thermally conductive silicone adhesive tape and thermally conductive silicone adhesive tape - Google Patents

Description

The present invention relates to a composition for a thermally conductive silicone adhesive tape and a thermally conductive silicone adhesive tape.

In general, in fields such as electronic component packages and power modules, screws and clips are sometimes used to fasten cooling members and semiconductors. However, fastening methods using screws and clips require many parts and processes, resulting in very poor manufacturing efficiency. This method also prevents the electronic devices themselves from being made smaller and thinner, which is very disadvantageous in terms of product design. 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 member and the semiconductor, thereby fastening the semiconductor element to the housing.

Specifically, a method is considered in which adhesiveness is imparted to a thermally conductive sheet interposed between the cooling member and the semiconductor, and the case and the semiconductor element are fixed. For example, there is a method in which adhesive is applied 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 has no thermal conductivity, the thermal conductivity of the sheet is significantly reduced. Therefore, thermally conductive adhesive tapes that use a thermally conductive filler in the adhesive, such as those described in Patent Documents 1 and 2, are known. In addition, Patent Document 3 describes a thermally conductive silicone adhesive tape that uses silicone as a base polymer, and is known to have excellent heat resistance, cold resistance, and durability.

However, while conventional adhesive tapes are advantageous for rework, they lack adhesive strength and pose problems in terms of reliability. 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.

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

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

On the other hand, it is known that addition-curing silicone compositions that use silver filler have reduced curing properties. Therefore, for example, when used in the aforementioned 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 properties and reliability.

JP 2014-34652 A JP 2014-62220 A JP 2008-260798 A

The present invention aims to provide a composition for a thermally conductive silicone adhesive tape that is easy to handle, has sufficient adhesive strength, and has high thermal performance, and a thermally conductive silicone adhesive tape that is easy to handle and can be easily mounted on a heat dissipating member.

（式（１）中、Ｒ^１は独立して炭素数１～１０のアルキル基、炭素数６～１０のアリール基、及び炭素数７～１０のアラルキル基から選ばれる基であり、Ｒ^２は炭素数２～８のアルケニル基である。０＜ａ１≦１００であり、０＜ｂ１≦１００であり、０≦ｃ１≦１００であり、０≦ｄ１≦１００であり、０≦ｅ１≦１００である。ただし、０．５≦ａ１／（ｄ１＋ｅ１）≦２．０の範囲を満たすものとする。）
（ｃ－２）：下記平均組成式（２）で表される三次元網状オルガノポリシロキサンレジン

（式（２）中、Ｒ^１は前記式（１）と同じであり、０＜ａ２≦１００であり、０≦ｃ２≦１００であり、０≦ｄ２≦１００であり、０＜ｅ２≦１００である。ただし、０．７≦ａ２／ｅ２≦２．５の範囲を満たすものとする。）
（ｄ）下記一般式（３）で表される有機ケイ素化合物：１～３０質量部

（ｎは１～２０の整数である。）
（ｅ）有機過酸化物：５～４０質量部 In order to solve the above problems, the present invention provides
A composition for a thermally conductive silicone adhesive tape, comprising:
The composition for a thermally conductive silicone adhesive tape comprises the following components (a) to (e):
(a) 100 parts by mass of a linear or branched organopolysiloxane having two or more alkenyl groups in one molecule; (b) 3,000 to 7,500 parts by mass of silver filler; (c) 150 to 450 parts by mass of a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (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

(In formula (1), ^R1 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 ^R2 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, with the proviso 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):

(In formula (2), ^R1 is the same as in formula (1), and 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100, with the proviso 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

(n is an integer from 1 to 20.)
(e) Organic peroxide: 5 to 40 parts by mass

This type of composition for thermally conductive silicone adhesive tape makes it possible to obtain a thermally conductive silicone adhesive tape that is easy to handle, has sufficient adhesive strength, and has high thermal performance.

The composition for 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 per molecule.

Such a composition for thermally conductive silicone adhesive tape can exhibit good wettability with the adherend interface and increase adhesive strength.

The composition for thermally conductive silicone adhesive tape preferably contains 10 to 60 mass % of the component (c-1) relative to the total amount of the three-dimensional network organopolysiloxane resin (c).

This type of composition for thermally conductive silicone adhesive tape can provide particularly good adhesive strength.

（式（４）中、Ｒ^３は、炭素原子数６～１５のアルキル基であり、Ｒ^４は、炭素原子数１～５のアルキル基であり、Ｒ^５は、炭素原子数１～６のアルキル基であり、ｍは１～３の整数であり、ｎは０～２の整数である。但しｍ＋ｎは１～３の整数である。）
（ｇ－２）下記一般式（５）で表されるジメチルポリシロキサン

（式（５）中、Ｒ^５は、前記式（４）と同じであり、ｐは５～１００の整数である。） In addition, it is preferable that the composition for a thermally conductive silicone adhesive tape further contains, as component (g), 1 to 20 parts by mass of one or more types selected from the following components (g-1) and (g-2):
(g-1) An alkoxysilane compound represented by the following average composition formula (4):

(In formula (4), ^R3 is an alkyl group having 6 to 15 carbon atoms, ^R4 is an alkyl group having 1 to 5 carbon atoms, ^R5 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):

(In formula (5), ^R5 is the same as in formula (4), and p is an integer of 5 to 100.)

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 in the matrix of component (a).

In addition, it is preferable that the (b) silver filler has an average particle size of 0.1 to 50 μm.

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

It is also preferable that the thermally conductive silicone adhesive tape composition has a thermal conductivity of 15.0 W/mK or more after curing.

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

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 of the composition for thermally conductive silicone adhesive tape.

This type of thermally conductive silicone adhesive tape is preferred because it is easy to handle.

It is also preferable that the substrate has a cured coating of fluorine-modified silicone on one or both sides.

This type of thermally conductive silicone adhesive tape is particularly preferred because it is easy to handle.

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 does not suffer from the curing inhibition seen in addition vulcanization systems. It also exhibits favorable adhesive strength, enabling strong fixation between the members and providing excellent reliability. In addition, the thermally conductive silicone adhesive tape of the present invention is easy to handle and can be easily mounted on the heat dissipating member.

The thermally conductive silicone adhesive tape composition of the present invention is therefore extremely effective as a thermally conductive member that is placed between a heat generating element and a heat dissipating member to transfer heat generated by the heat generating element to the heat dissipating member and to fix the heat in place.

As mentioned above, there was a need to develop a composition for thermally conductive silicone adhesive tape that is easy to handle, has sufficient adhesive strength, and has high thermal performance.

As a result of intensive research conducted by the inventors to achieve the above object, they 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 that are easy to handle, have good adhesive strength with a heat dissipation member, and have excellent thermal conductivity, and thus completed the present invention.

（式（１）中、Ｒ^１は独立して炭素数１～１０のアルキル基、炭素数６～１０のアリール基、及び炭素数７～１０のアラルキル基から選ばれる基であり、Ｒ^２は炭素数２～８のアルケニル基である。０＜ａ１≦１００であり、０＜ｂ１≦１００であり、０≦ｃ１≦１００であり、０≦ｄ１≦１００であり、０≦ｅ１≦１００である。ただし、０．５≦ａ１／（ｄ１＋ｅ１）≦２．０の範囲を満たすものとする。）
（ｃ－２）：下記平均組成式（２）で表される三次元網状オルガノポリシロキサンレジン

（式（２）中、Ｒ^１は前記式（１）と同じであり、０＜ａ２≦１００であり、０≦ｃ２≦１００であり、０≦ｄ２≦１００であり、０＜ｅ２≦１００である。ただし、０．７≦ａ２／ｅ２≦２．５の範囲を満たすものとする。）
（ｄ）下記一般式（３）で表される有機ケイ素化合物：１～３０質量部

（ｎは１～２０の整数である。）
（ｅ）有機過酸化物：５～４０質量部 That is, the present invention provides:
A composition for a thermally conductive silicone adhesive tape, comprising:
The composition for a thermally conductive silicone adhesive tape contains the following components (a) to (e):
(a) 100 parts by mass of a linear or branched organopolysiloxane having two or more alkenyl groups in one molecule; (b) 3,000 to 7,500 parts by mass of silver filler; (c) 150 to 450 parts by mass of a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (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

(In formula (1), ^R1 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 ^R2 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, with the proviso 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):

(In formula (2), ^R1 is the same as in formula (1), and 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100, with the proviso 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

(n is an integer from 1 to 20.)
(e) Organic peroxide: 5 to 40 parts by mass

Each component is described in detail below, but the present invention is not limited to these.

（式中、Ｒ^６は独立して炭素数１～１０のアルキル基、炭素数６～１０のアリール基、及び炭素数７～１０のアラルキル基から選ばれる基であり、Ｘは炭素数２～８のアルケニル基である。ｄ及びｅはそれぞれ０又は１以上の正数、ｆは１以上の正数、ｇは２以上の正数である。なお、ｄ～ｇで括られたシロキサン単位の結合順序は、ブロックであってもランダムであってもよい。） (a) Linear or branched organopolysiloxane having two or more alkenyl groups per molecule Component (a) is a linear or branched organopolysiloxane having two or more alkenyl groups per 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).

(In the formula, R ⁶ 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 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 either block or random.)

Examples of R ⁶ 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.

In addition, all of ^R6 may be the same or different. Unless special properties such as solvent resistance are required for ^R6 , it is preferable that all of R6 are methyl groups in terms of cost, availability, chemical stability, environmental load, etc.

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 vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl groups, of which lower alkenyl groups such as vinyl and allyl are preferred, with vinyl being more preferred.

d is a positive number of 0 or 1 or more, but is preferably a positive number in the range of 10≦d≦10,000, more preferably a positive number in the range of 50≦d≦2,000, and even more preferably a positive number in the range of 100≦d≦1,000.

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.

f is a positive number equal to or greater than 1, but 0<f/(d+f)≦0.5 is preferred, and 0<f/(d+f)≦0.1 is even more preferred.

g is a positive number of 2 or more, but 0<g/(d+g)≦0.5 is preferable, and 0<g/(d+g)≦0.1 is more preferable.

Component (a) may be oil-like or gum-like, and may be used alone or in combination with multiple components of different viscosities. Its average degree of polymerization is preferably 10 to 5,000, and more preferably 100 to 2,000.

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).

(b) Silver filler The (b) component is a silver filler that serves as a thermally conductive filler. The manufacturing method of the silver filler is not particularly limited, but examples thereof include electrolysis, heat treatment, atomization, reduction, etc. The shape of the silver filler is not particularly limited, and may be flake, spherical, granular, irregular, needle-like, etc.

The (b) component 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 thermally conductive filler may be used alone or in combination of two or more types. Also, two or more types of particles with different average particle sizes may be used. In the present invention, the average particle size is the volume average particle size, and is a value measured using a Microtrack particle size distribution measuring device MT3300EX (Nikkiso Co., Ltd.).

Component (b) may be subjected to various known surface treatments. Specific examples include treatment with coupling agents such as silanes and titanates, and plasma treatment.

The amount of component (b) 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, per 100 parts by mass of component (a).

If the amount of component (b) is more than 7,500 parts by mass, the thermally conductive adhesive layer becomes brittle and workability decreases, whereas if the amount is less than 3,000 parts by mass, the desired thermal conductivity cannot be obtained.
The component (b) may be used alone or in combination of two or more.

(c) Three-dimensional network organopolysiloxane resin The three-dimensional network organopolysiloxane resin, which is component (c), imparts cohesive strength to the composition for thermally conductive silicone adhesive tape, imparting workability, and also functions to obtain good adhesive strength in the adhesive layer after curing.

（式（１）中、Ｒ^１は独立して炭素数１～１０のアルキル基、炭素数６～１０のアリール基、及び炭素数７～１０のアラルキル基から選ばれる基であり、Ｒ^２は炭素数２～８のアルケニル基である。０＜ａ１≦１００であり、０＜ｂ１≦１００であり、０≦ｃ１≦１００であり、０≦ｄ１≦１００であり、０≦ｅ１≦１００である。ただし、０．５≦ａ１／（ｄ１＋ｅ１）≦２．０の範囲を満たすものとする。）
（ｃ－２）：下記平均組成式（２）で表される三次元網状オルガノポリシロキサンレジン

（式（２）中、Ｒ^１は前記式（１）と同じであり、０＜ａ２≦１００であり、０≦ｃ２≦１００であり、０≦ｄ２≦１００であり、０＜ｅ２≦１００である。ただし、０．７≦ａ２／ｅ２≦２．５の範囲を満たすものとする。） Component (c) is composed of a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (c-2):
(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.

(In formula (1), ^R1 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 ^R2 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, with the proviso 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):

(In formula (2), ^R1 is the same as in formula (1), and 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100, with the proviso that the range of 0.7≦a2/e2≦2.5 is satisfied.)

Component (c-1) Component (c-1) is 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.

In the above formula, ^R1 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. Specific examples include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, and heptyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups such as benzyl and phenethyl groups; and halogen-substituted alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl groups, with a methyl group being particularly preferred.

^R2 is an alkenyl group having 2 to 8 carbon atoms, specific examples of which include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a cyclohexenyl group, and a heptenyl group, with a vinyl group being particularly preferred.

In the above formula, 0<a1≦100, preferably 1≦a1≦50. 0<b1≦100, preferably 1≦b1≦50. 0≦c1≦100, preferably 0≦c1≦50. 0≦d1≦100, preferably 0≦d1≦50. 0≦e1≦100, preferably 1≦e1≦50. However, the range of 0.5≦a1/(d1+e1)≦2.0 is satisfied, preferably 0.6≦a1/(d1+e1)≦1.8, and more preferably 0.7≦a1/(d1+e1)≦1.5 is satisfied.

If the ratio is less than 0.5, it becomes difficult to highly fill the silver filler (b), and the thermal conductivity of the composition for thermally conductive silicone adhesive tape decreases. Alternatively, if the ratio exceeds 2.0, the cohesive strength of the composition for thermally conductive silicone adhesive tape decreases, and workability decreases.

The alkenyl group content in the molecule of component (c-1) is 0.05 to 0.15 mol/100g, preferably 0.06 to 0.14 mol/100g, and more preferably 0.07 to 0.12 mol/100g. If the alkenyl group content in the molecule is less than 0.05 mol/100g, it is difficult to obtain sufficient adhesive strength, which is undesirable, and if it is more than 0.15 mol/100g, the composition for thermally conductive silicone adhesive tape becomes hard and brittle, reducing workability, which is undesirable.

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

In the formula, ^R1 is the same as in the formula (1), and 0<a2≦100, preferably 1≦a2≦50. Also, 0≦c2≦100, preferably 0≦c2≦50. Also, 0≦d2≦100, preferably 0≦d2≦50. And, 0<e2≦100, preferably 1≦e2≦50. However, the range of 0.7≦a2/e2≦2.5 is satisfied, preferably 0.8≦a2/e2≦2.2, and more preferably 0.9≦a2/e2≦2.0 is satisfied.

If the a2/e2 ratio is less than 0.7, it becomes difficult to highly fill the silver filler (b), and the thermal conductivity of the composition for thermally conductive silicone adhesive tape decreases. Alternatively, if the ratio exceeds 2.5, the cohesive strength of the composition for thermally conductive silicone adhesive tape decreases, and the desired adhesive strength cannot be obtained.

Unless special properties such as solvent resistance are required, it is preferred that all R ^1s are methyl groups for reasons of cost, availability, chemical stability, environmental impact, and the like.

When the three-dimensional network organopolysiloxane resin, component (c), is a solid, it can be used as a 50 to 70 mass% toluene solution. In that case, the kinetic viscosity may be 10 to 500 mm ² /s, preferably 100 to 250 mm ² /s. The kinetic viscosity is a value at 25°C measured using a Cannon-Fenske viscometer as described in JIS Z8803:2011.

Method for measuring the ratio of M units, T units, and Q units In the organopolysiloxane resin having a three-dimensional network (resinous) structure in the present invention, the ratio of branched siloxane units, either or both of trifunctional R ¹ SiO _3/2 units (T units) and tetrafunctional SiO _4/2 units (Q units), to monofunctional R ¹ ₃ SiO _1/2 units (M units), i.e., the value of a1/(d1+e1) in component (c-1) and the value of a2/e2 in component (c-2) can be determined by ²⁹ Si-NMR.

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

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 component (c) added is less than 150 parts by mass, the thermally conductive adhesive layer will not be able to obtain the desired adhesive strength. If it exceeds 450 parts by mass, the composition for thermally conductive silicone adhesive tape will be brittle and lack flexibility, making it difficult to work with.

The component (c) itself is a solid or a viscous liquid at room temperature, and 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 amount of resin excluding the solvent falls within the above range.

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

（ｎは１～２０の整数である。） Component (d) is an organosilicon compound represented by the following general formula (3), and serves as an adhesive component to improve wettability with the adherend.

(n is an integer from 1 to 20.)

Furthermore, as a result of intensive research into the present invention, it was discovered that component (d) also has the effect of assisting the sintering of silver in a peroxide vulcanization system, effectively improving thermal conductivity.

Component (d) may be used alone or in appropriate combination of two or more. 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, preferably 4 to 15.

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 will not be obtained.

(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-butylperoxyacetate and t-butylperoxybenzoate, 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.

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

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

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

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.

上記式（９）中、Ｒ^６は炭素原子数１～１０、好ましくは炭素原子数１～８の１価炭化水素基である。但し、アルケニル基等の脂肪族不飽和基は含まない。１価炭化水素基としては、例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ－ブチル基、ペンチル基、ネオペンチル基、ヘキシル基、シクロヘキシル基、オクチル基、ノニル基、及びデシル基等のアルキル基、フェニル基、トリル基、キシリル基、及びナフチル基等のアリール基、ベンジル基、フェニルエチル基、及びフェニルプロピル基等のアラルキル基等が挙げられる。中でも、アルキル基又はアリール基が好ましく、より好ましくはメチル基である。また、ｒは０．７～２．１の正数であり、好ましくは、１．０～２．０の正数である。ｓは０．００１～１．０の正数であり、好ましくは、０．０１～１．０の正数である。かつ、ｒ＋ｓが０．８～３．０の範囲を満たす数であり、好ましくは、１．５～２．５の範囲を満たす数である。 The organohydrogenpolysiloxane can be represented by the following average composition formula (9).

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 preferable, and a methyl group is more preferable. 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.

The organohydrogenpolysiloxane has 2 to 200, preferably 3 to 100, and more preferably 4 to 50 hydrosilyl groups per molecule. The hydrosilyl groups may be located at either the ends of the molecular chain or in the middle of the molecular chain, or may be located at both. The molecular structure of the organohydrogenpolysiloxane may be linear, cyclic, branched, or a three-dimensional network structure. The number of silicon atoms (degree of polymerization) per 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 the developing solvent.

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 terminals, dimethylsiloxane-methylhydrogensiloxane copolymer capped with trimethylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer capped with trimethylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylhydrogensiloxane-diphenylsiloxane copolymer capped with trimethylsiloxy groups at both molecular chain terminals, and dimethylsiloxane-methylhydrogensiloxane-diphenylsiloxane capped with trimethylsiloxy groups at both molecular chain terminals. and dimethylsiloxane copolymers, methylhydrogenpolysiloxanes capped at both molecular terminals with dimethylhydrogensiloxy groups, dimethylpolysiloxanes capped at both molecular terminals with dimethylhydrogensiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymers capped at both molecular terminals with dimethylhydrogensiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers capped at both molecular terminals with dimethylhydrogensiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers capped at both molecular terminals with dimethylhydrogensiloxy groups, methylphenylpolysiloxanes capped at both molecular terminals with dimethylhydrogensiloxy groups, and diphenylpolysiloxanes capped at both molecular terminals with dimethylhydrogensiloxy groups, and those in which some or all of the methyl groups in each of the above compounds have been replaced with other alkyl groups such as ethyl groups or propyl groups, ⁷ ₃ SiO _1/2 (wherein R ⁷ is a monovalent hydrocarbon group other than an alkenyl group, and is the same as R ¹ ), an organosiloxane copolymer consisting of a siloxane unit represented by the formula: R ⁷ ₂ HSiO _1/2 and a siloxane unit represented by the formula: SiO _4/2 , an organosiloxane copolymer consisting of a siloxane unit represented by the formula: R ⁷ ₂ HSiO _1/2 and a siloxane unit represented by the formula: SiO _4/2 , an organosiloxane copolymer consisting of a siloxane unit represented by the formula: R ⁷ HSiO _2/2 and a siloxane unit represented by the formula: R ⁷ SiO _3/2 or a siloxane unit represented by the formula: HSiO _3/2 . Two or more of these organohydrogenpolysiloxanes may be used in combination.

The amount of component (f) is 1 to 30 parts by mass, preferably 5 to 20 parts by mass, per 100 parts by mass of component (a). When the amount of component (f) 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.

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

（式（４）中、Ｒ^３は、炭素原子数６～１５のアルキル基であり、Ｒ^４は、炭素原子数１～５のアルキル基であり、Ｒ^５は、炭素原子数１～６のアルキル基であり、ｍは１～３の整数であり、ｎは０～２の整数である。但しｍ＋ｎは１～３の整数である。）
（ｇ－２）下記一般式（５）で表されるジメチルポリシロキサン

（式（５）中、Ｒ^５は、前記式（４）と同じであり、ｐは５～１００の整数である。） (g-1) An alkoxysilane compound represented by the following average composition formula (4):

(In formula (4), ^R3 is an alkyl group having 6 to 15 carbon atoms, ^R4 is an alkyl group having 1 to 5 carbon atoms, ^R5 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):

(In formula (5), ^R5 is the same as in formula (4), and p is an integer of 5 to 100.)

In the above formula (4), examples of the alkyl group represented by ^R3 include a hexyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, etc. When the alkyl group represented by ^R3 has a carbon atom number in the range of 6 to 15, the wettability of the silver filler, which is the above-mentioned component (b), is sufficiently improved, the handleability is good, and the properties of the composition for a thermally conductive silicone adhesive tape are good.

^R4 is an alkyl group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably a methyl group.

^R5 is an alkyl group having 1 to 6 carbon atoms, 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.

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

If the amount of component (g) added is 1 part by mass or more, component (b) can be uniformly filled into component (a), and if the amount is 20 parts by mass or less, the adhesive strength of the thermally conductive adhesive layer will not decrease.

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

[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 any conventionally known method. Preferably, components (a), (b), and (c), as well as optional component (g), are mixed together, and then components (d), (e), and optional component (f) are mixed.

[Thermal conductive silicone adhesive tape]
The thermally conductive silicone adhesive tape of the present invention can be obtained by applying the composition for thermally conductive silicone adhesive tape to a substrate described below, forming it into a thin tape shape, and drying it. 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 composition for thermally conductive silicone adhesive tape 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 composition for thermally conductive silicone adhesive tape in an uncured state, and when it is mounted between the heat dissipation member and the heat generating member, it is subjected to a heat curing treatment to firmly bond the two.

The thickness of the thermally conductive adhesive layer of the present invention is preferably 50 to 300 μm, and 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.

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 onto the adhesive surface, handling such as transportation and cutting to a fixed length can be facilitated. 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.

（ｐは１～５であり、ｑは３～１０である） The separator film is preferably a polyethylene laminated paper or a PET film, which is subjected to a release treatment 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).

(p is 1 to 5, and q is 3 to 10).

Commercially available products of the fluorine-modified silicone include, for example, X-70-201, X-70-258, and X-41-3035 manufactured by Shin-Etsu Chemical Co., Ltd. Methods for forming onto a substrate include coating a liquid material onto the substrate using a bar coater, knife coater, comma coater, spin coater, etc., but are not limited to the methods described above.

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. In addition, by having the separator film described above, one separator film can be peeled off and then attached to a heat-generating electronic component or heat-dissipating component, and then the remaining separator film can be peeled off and attached to a cooling component, etc., so that it can be interposed between the cooling component and the heat-generating electronic component or heat-dissipating component.

Furthermore, by carrying out a heat treatment after mounting, the composition for thermally conductive silicone adhesive tape hardens and the silver filler partially sinters, resulting in good thermal conductivity and adhesion between the components, enabling strong fixation. The heat treatment after mounting is carried out at 130°C to 190°C for 20 to 90 minutes, preferably at 150°C to 170°C for 30 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 15.0 W/mK or more, preferably 30.0 W/mK or more, and more preferably 40.0 W/mK or more.

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

The components (a) to (g) constituting the thermally conductive silicone adhesive tape composition used in the following examples and comparative examples are as follows:

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

(b) Component:
(b-1) Spherical silver filler having a volume average particle diameter of 1 μm (b-2) Flake-shaped silver filler having a volume average particle diameter of 3 μm (b-3) Flake-shaped silver filler having a volume average particle diameter of 10 μm

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

(d) Component: Octenyltrimethoxysilane

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

（前記平均組成式（９）のＲ^６＝メチル基、ｒ＝１．４、ｓ＝０．８に相当） Component (f): an organohydrogenpolysiloxane represented by the following formula:

(corresponding to the above average composition formula (9) where R ⁶ = methyl group, r = 1.4, and s = 0.8)

Component (g-1): decyltrimethoxysilane Component (g-2): dimethylpolysiloxane having a trimethoxysilyl group at one end, represented by the following formula:

The above components (a), (b), (c), and (g) were charged in the amounts shown in Tables 1 and 2 below into a Shinagawa universal mixer 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.

[Forming 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 fluorine-modified silicone release agent (product name: X-41-3035, manufactured by Shin-Etsu Chemical Co., Ltd.).

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

The separator film on one side was peeled off, the adhesive layer surface was attached to an aluminum heat sink, and then when the separator film on the other side was peeled off, an evaluation was made based on whether the attached adhesive layer or composite was fixed to the heat sink without slipping. Those that were fixed without slipping were marked with an O, and those that were misaligned were marked with an X in the table. Note that the following evaluation was not performed on those that were rated as X for handling.

(2) Thermal conductivity: The thermally conductive silicone adhesive tape with the separator films on both sides removed was sandwiched between aluminum plates and uniformly pressed, then heated and cured at 150°C/100 psi x 1 hr 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 ( ^mm2.K /W)

(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.

In Examples 1 to 11, excellent transferability and handling properties were obtained, as well as excellent thermal conductivity and adhesive strength after heat-pressing.

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

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.

In Comparative Example 3, the amount of silicone resin (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.

In Comparative Example 4, the amount of silicone resin (c) was more than 450 parts by mass per 100 parts by mass of component (a), so the thermally conductive silicone adhesive tape composition had poor flexibility and poor transferability.

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

In Comparative Examples 7 and 8, the amount of peroxide (e) was not within the range of 5 to 40 parts by mass, so the desired adhesive strength and thermal conductivity could not be obtained.

As described above, the present invention has been shown to provide a composition for thermally conductive silicone adhesive tape that is easy to handle, has excellent transferability to components, and has good adhesive strength and thermal conductivity.

（式（１）中、Ｒ^１は独立して炭素数１～１０のアルキル基、炭素数６～１０のアリール基、及び炭素数７～１０のアラルキル基から選ばれる基であり、Ｒ^２は炭素数２～８のアルケニル基である。０＜ａ１≦１００であり、０＜ｂ１≦１００であり、０≦ｃ１≦１００であり、０≦ｄ１≦１００であり、０≦ｅ１≦１００である。ただし、０．５≦ａ１／（ｄ１＋ｅ１）≦２．０の範囲を満たすものとする。）
（ｃ－２）：下記平均組成式（２）で表される三次元網状オルガノポリシロキサンレジン

（式（２）中、Ｒ^１は前記式（１）と同じであり、０＜ａ２≦１００であり、０≦ｃ２≦１００であり、０≦ｄ２≦１００であり、０＜ｅ２≦１００である。ただし、０．７≦ａ２／ｅ２≦２．５の範囲を満たすものとする。）
（ｄ）下記一般式（３）で表される有機ケイ素化合物：１～３０質量部

（ｎは１～２０の整数である。）
（ｅ）有機過酸化物：５～４０質量部
［２］：前記熱伝導性シリコーン接着テープ用組成物は、さらに（ｆ）成分として、１分子中に２個以上のヒドロシリル基を有するオルガノハイドロジェンポリシロキサンを１～３０質量部含むものである上記［１］の熱伝導性シリコーン接着テープ用組成物。
［３］：前記熱伝導性シリコーン接着テープ用組成物は、前記（ｃ）三次元網状オルガノポリシロキサンレジンの総量に対する前記（ｃ－１）成分の割合が１０～６０質量％のものである上記［１］又は上記［２］の熱伝導性シリコーン接着テープ用組成物。
［４］：前記熱伝導性シリコーン接着テープ用組成物は、さらに（ｇ）成分として、下記（ｇ－１）成分及び（ｇ－２）成分から選ばれる１種以上を１～２０質量部含むものである上記［１］、上記［２］又は上記［３］の熱伝導性シリコーン接着テープ用組成物。
（ｇ－１）下記平均組成式（４）で表されるアルコキシシラン化合物

（式（４）中、Ｒ^３は、炭素原子数６～１５のアルキル基であり、Ｒ^４は、炭素原子数１～５のアルキル基であり、Ｒ^５は、炭素原子数１～６のアルキル基であり、ｍは１～３の整数であり、ｎは０～２の整数である。但しｍ＋ｎは１～３の整数である。）
（ｇ－２）下記一般式（５）で表されるジメチルポリシロキサン

（式（５）中、Ｒ^５は、前記式（４）と同じであり、ｐは５～１００の整数である。）
［５］：前記（ｂ）銀フィラーは、平均粒径が０．１～５０μｍである上記［１］、上記［２］、上記［３］、又は上記［４］の熱伝導性シリコーン接着テープ用組成物。
［６］：前記熱伝導性シリコーン接着テープ用組成物は、その硬化物の熱伝導率が１５．０Ｗ／ｍＫ以上となるものである上記［１］、上記［２］、上記［３］、上記［４］又は上記［５］の熱伝導性シリコーン接着テープ用組成物。
［７］：熱伝導性接着層の片面または両面に基材を有する熱伝導性シリコーン接着テープであって、前記熱伝導性接着層は上記［１］、上記［２］、上記［３］、上記［４］、上記［５］又は上記［６］の熱伝導性シリコーン接着テープ用組成物からなるものである熱伝導性シリコーン接着テープ。
［８］：前記基材は片面または両面にフッ素変性シリコーンの硬化皮膜を有する上記［７］の熱伝導性シリコーン接着テープ。 The present specification includes the following aspects.
[1]: A composition for a thermally conductive silicone adhesive tape, the composition for a thermally conductive silicone adhesive tape comprising the following components (a) to (e):
(a) 100 parts by mass of a linear or branched organopolysiloxane having two or more alkenyl groups in one molecule; (b) 3,000 to 7,500 parts by mass of silver filler; (c) 150 to 450 parts by mass of a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (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

(In formula (1), ^R1 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 ^R2 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, with the proviso 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):

(In formula (2), ^R1 is the same as in formula (1), and 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100, with the proviso 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

(n is an integer from 1 to 20.)
(e) organic peroxide: 5 to 40 parts by mass [2]: the composition for thermally conductive silicone adhesive tape according to [1] above, further comprising, as component (f), 1 to 30 parts by mass of an organohydrogenpolysiloxane having two or more hydrosilyl groups per molecule.
[3]: The composition for a thermally conductive silicone adhesive tape according to [1] or [2] above, wherein the proportion of component (c-1) relative 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 [1], [2] or [3] above, further comprising, as component (g), from 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):

(In formula (4), ^R3 is an alkyl group having 6 to 15 carbon atoms, ^R4 is an alkyl group having 1 to 5 carbon atoms, ^R5 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):

(In formula (5), ^R5 is the same as in formula (4), and p is an integer of 5 to 100.)
[5]: The composition for a thermally conductive silicone adhesive tape according to [1], [2], [3], or [4] above, wherein the (b) silver filler has an average particle size of 0.1 to 50 μm.
[6]: The composition for a thermally conductive silicone adhesive tape according to [1], [2], [3], [4] or [5] above, 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, the thermally conductive adhesive layer being made of the composition for a thermally conductive silicone adhesive tape according to [1], [2], [3], [4], [5] or [6] above.
[8]: The thermally conductive silicone adhesive tape of [7] above, wherein the substrate has a cured coating of fluorine-modified silicone on one or both sides.

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 within the technical scope of the present invention.

Claims (8)

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) 100 parts by mass of a linear or branched organopolysiloxane having two or more alkenyl groups in one molecule; (b) 3,000 to 7,500 parts by mass of silver filler; (c) 150 to 450 parts by mass of a three-dimensional network organopolysiloxane resin containing the following components (c-1) and (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

(In formula (1), ^R1 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 ^R2 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, with the proviso 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):

(In formula (2), ^R1 is the same as in formula (1), and 0<a2≦100, 0≦c2≦100, 0≦d2≦100, and 0<e2≦100, with the proviso 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

(n is an integer from 1 to 20.)
(e) Organic peroxide: 5 to 40 parts by mass The composition for thermally conductive silicone adhesive tape according to claim 1, further comprising 1 to 30 parts by mass of an organohydrogenpolysiloxane having two or more hydrosilyl groups in one molecule as component (f). 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 %. 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):

(In formula (4), ^R3 is an alkyl group having 6 to 15 carbon atoms, ^R4 is an alkyl group having 1 to 5 carbon atoms, ^R5 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):

(In formula (5), ^R5 is the same as in formula (4), and p is an integer of 5 to 100.) The composition for thermally conductive silicone adhesive tape according to claim 1, characterized in that the (b) silver filler has an average particle size of 0.1 to 50 μm. The composition for thermally conductive silicone adhesive tape according to any one of claims 1 to 5, characterized in that the thermal conductivity of the cured product is 15.0 W/mK or more. 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. The thermally conductive silicone adhesive tape according to claim 7, characterized in that the substrate has a cured coating of fluorine-modified silicone on one or both sides.