JP7764581B2 - Two-component curing composition set, cured product, and electronic device - Google Patents

Description

The present invention relates to a two-component curing composition set, a cured product, and an electronic device.

As heat-generating electronic components such as computer CPUs (central processing units) become smaller and more powerful, the amount of heat generated per unit area by these components has become extremely large. This amount of heat can reach approximately 20 times that of an iron. To prevent these heat-generating electronic components from breaking down over the long term, they must be cooled. Metal heat sinks and housings are used for cooling, but when a heat-generating electronic component is placed in direct contact with a heat sink or similar, microscopic air exists at the interface, which can impede heat conduction. Therefore, to efficiently transfer heat, a heat-generating electronic component and a heat sink or similar are sometimes placed with a thermally conductive material between them.

An example of a thermally conductive material is thermally conductive grease, which is made by adding thermally conductive powder to room-temperature curing liquid silicone rubber. Room-temperature curing liquid silicone rubber is mainly classified into one-component and two-component types, and the two-component type is further divided into condensation reaction and addition reaction types. Thermally conductive grease containing two-component liquid silicone rubber is used as a two-component curing composition set containing two different compositions.

For example, Patent Document 1 describes that an addition reaction type silicone rubber composition containing an alkenyl group-containing organopolysiloxane, an organohydrogenpolysiloxane, a platinum catalyst, and an adhesion promoter is less susceptible to the effects of cure inhibitors and has excellent adhesion.

Japanese Patent Application Laid-Open No. 2006-22284

Two-component curing composition sets are used by mixing the two compositions and then applying them to a specified area. Generally, the thermal conductivity of the cured product obtained from the two compositions is controlled by adjusting the amount and type of thermally conductive filler added. However, if too much thermally conductive filler is added in order to increase thermal conductivity, the viscosity of the two compositions and their mixture increases, resulting in problems such as reduced ease of application and handling.

When the inventors examined conventional thermally conductive greases such as those described in Patent Document 1, they found that the conventional thermally conductive greases were insufficient in at least one of their handling properties and thermal conductivity.

The present invention has been made in consideration of the above-mentioned problems, and aims to provide a two-component curing composition set that is easy to handle and has excellent thermal conductivity, a cured product obtained from the two-component curing composition set, and an electronic device equipped with the cured product.

As a result of extensive research into achieving the above objective, the inventors discovered that a two-component curable composition set in which the thermal resistance values and viscosities of the first and second components are within a specified range can solve the above problem, leading to the completion of the present invention.

That is, the present invention is as follows.
[1]
A first agent and a second agent are provided,
the first agent and the second agent each independently have a thermal resistance value at a thickness of 1.0 mm, as measured by a method in accordance with ASTM D5470, of 1.4 to 2.1 ^cm2 ·°C/W;
The first agent and the second agent each have a viscosity, as measured by a rotational rheometer, of 50 to 120 Pa s.
Two-component curing composition set.
[2]
the first agent comprises a surfactant A1, a vinyl-modified organopolysiloxane B1 having a viscosity of 80 to 120 mPa·s, a thermally conductive filler C1, and an addition reaction catalyst D1;
the second agent comprises a surfactant A2, a vinyl-modified organopolysiloxane B2 having a viscosity of 80 to 120 mPa·s, a thermally conductive filler C2, and a hydrosilyl-modified organopolysiloxane E2 having a viscosity of 1 to 100 mPa·s;
The two-component curing composition set according to [1].
[3]
the vinyl-modified organopolysiloxane B1 and the vinyl-modified organopolysiloxane B2 each independently have an average of 2.0 or more vinyl groups per molecule,
The hydrosilyl-modified organopolysiloxane E2 has an average of more than 2.0 hydrosilyl groups per molecule.
The two-component curing composition set according to [2].
[4]
In the first agent, the amount of the vinyl-modified organopolysiloxane B1 is 100 parts by weight.
The content of the surfactant A1 is 5 to 25 parts by weight,
The content of the thermally conductive filler C1 is 1500 to 2400 parts by weight.
The two-component curing composition set according to [2] or [3].
[5]
In the second agent, for a total of 100 parts by weight of the vinyl-modified organopolysiloxane B2 and the hydrosilyl-modified organopolysiloxane E2,
The content of the surfactant A2 is 5 to 25 parts by weight,
The content of the thermally conductive filler C2 is 1500 to 2400 parts by weight.
[2] The two-component curing composition set according to any one of [2] to [4].
[6]
The surfactant A1 and the surfactant A2 are copolymers having (meth)acrylic monomer units α having a carboxy group, (meth)acrylic monomer units β having a tertiary amino group, and (meth)acrylic monomer units γ having a siloxane skeleton.
[2] to [5]. The two-component curing composition set according to any one of [2] to [5].
[7]
The number average molecular weight of the monomer unit γ is 1,500 to 50,000.
The two-component curing composition set according to [6].
[8]
In the copolymer, relative to 100 parts by weight in total of the monomer units α, β, and γ,
the content of the monomer unit α is 0.08 to 6.0 parts by weight,
the content of the monomer unit β is 0.02 to 4.0 parts by weight,
the content of the monomer unit γ is 90.0 to 99.9 parts by weight;
The two-component curing composition set according to [6] or [7].
[9]
The surfactant A1 and the surfactant A2 each independently have a weight average molecular weight of 20,000 to 150,000.
[2] - [8] The two-component curing composition set according to any one of [2] to [8].
[10]
The hydrosilyl-modified organopolysiloxane E2 comprises a hydrosilyl-modified organopolysiloxane E21 having hydrosilyl groups at both ends and a hydrosilyl-modified organopolysiloxane E22 having hydrosilyl groups in side chains.
[2] - [9] The two-component curing composition set according to any one of [2] to [9].
[11]
The thermally conductive filler C1 and the thermally conductive filler C2 are each independently one or more selected from the group consisting of boron nitride, aluminum nitride, aluminum oxide, silicon nitride, silicon oxide, magnesium oxide, metallic aluminum, and zinc oxide.
[2] to [10]. The two-component curing composition set according to any one of [2] to [10].
[12]
The thermally conductive filler C1 and the thermally conductive filler C2 contain aluminum oxide powder.
The two-component curing composition set according to [11].
[13]
the first agent and the second agent are mixed in equal volumes, molded into a sheet, and then heat-cured at 60°C for 20 minutes, resulting in a sheet having a withstand voltage of 8 kV/mm or more as measured in accordance with JIS C2110;
[1] The two-component curing composition set according to any one of [1] to [12].
[14]
The thickness of the mixture when a load of 50 N is applied per 10 mm x 10 mm area to a mixture obtained by mixing the first agent and the second agent in equal volumes is 70 to 120 μm.
[14] The two-component curing composition set according to any one of [1] to [13].
[15]
The first agent and the second agent are represented by the following formula:
R ¹ _a R ² _b Si(OR ³ ) _4-(a+b)
( ^Each R1 is independently an alkyl group having 1 to 15 carbon atoms, ^each R2 is independently a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms, each ^R3 is independently an alkyl group having 1 to 6 carbon atoms, a is 1 to 3, b is 0 to 2, and a+b is 1 to 3.)
does not contain organosilane represented by
[15] The two-component curing composition set according to any one of [1] to [14].
[16]
Used as a thermally conductive heat dissipation material,
[16] The two-component curing composition set according to any one of [1] to [15].
[17]
[17] The two-component curing composition set according to any one of [1] to [16], wherein the two-component curing composition set is obtained from a mixture of the first component and the second component.
cured product.
[18]
Used as a thermally conductive heat dissipation material,
The cured product according to [17].
[19]
An electronic component, the cured product according to [18], and a heat sink,
the electronic component and the heat sink are in contact with each other via the cured product.
electronic equipment.

The present invention provides a two-component curing composition set that is easy to handle and has excellent thermal conductivity, a cured product obtained from the two-component curing composition set, and an electronic device equipped with the cured product.

The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"). However, the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present invention.

1. Two-component curing composition set The two-component curing composition set of this embodiment comprises a first part and a second part, and the first and second parts each independently have a thermal resistance value at a thickness of 1.0 mm, measured by a method in accordance with ASTM D5470, of 1.4 to 2.1 ^cm2 °C/W (both end values included; the same applies hereinafter unless otherwise specified), and the first and second parts each independently have a viscosity, measured with a rotational rheometer, of 50 to 120 Pa s.

The present inventors have found that when the thermal resistance values of the first and second agents are each independently 1.4 to 2.1 ^cm2 ·°C/W and the viscosities are each independently 50 to 120 Pa·s, an excellent balance between thermal conductivity and handleability is achieved, and the thermal conductivity and handleability required for practical use are satisfied.

1.1. Thermal Resistance Value The thermal resistance values of the first and second components at a thickness of 1.0 mm, measured according to a method in accordance with ASTM D5470, are each independently 1.4 to 2.1 ^cm2 ·°C/W, preferably 1.5 to 2.0 ^cm2 ·°C/W. Because the thermal resistance value is 2.1 ^cm2 ·°C/W or less, the cured product obtained from the two-component curing composition set of this embodiment can meet the thermal conductivity required for practical use. Furthermore, because the thermal resistance value is 1.4 ^cm2 ·°C/W or more, the viscosity of the first and second components is not too high, and the two-component curing composition set of this embodiment can meet the handleability required for practical use. The thermal resistance values of the first and second components are measured at a thickness of 1.0 mm according to a method in accordance with ASTM D5470, more specifically, by the method described in the Examples.

The thermal conductivity of the first and second components, measured by a method in accordance with ASTM D5470, is preferably 4.7 to 7.0 W/m·K, and more preferably 5.0 to 6.5 W/m·K. The thermal conductivity of the first and second components is measured by a method in accordance with ASTM D5470, and more specifically, is measured by the method described in the Examples.

In order to achieve the thermal resistance and thermal conductivity of the first and second agents within the above ranges, for example, the particle size and content of the thermally conductive filler contained in the first and second agents may be adjusted, or a filler with high thermal conductivity may be used. An example of the specific composition of the first and second agents will be described below.

1.2. Viscosity The viscosity of the first and second parts, measured using a rotational rheometer, is independently 50 to 120 Pa·s, preferably 60 to 110 Pa·s. Because the viscosity is 50 Pa·s or higher, the two-component curing composition set of this embodiment can meet the handleability requirements for practical use. Furthermore, because the viscosity is 120 Pa·s or lower, the thermal conductivity is not too low, and the cured product obtained from the two-component curing composition set of this embodiment can meet the thermal conductivity requirements for practical use.

In this specification, the viscosity of the first and second components measured with a rotational rheometer is measured at 25°C and a shear rate of 10 s ^-1 . The viscosity can be measured, for example, using a rotational rheometer "HANKE MARSIII" manufactured by Thermo Fisher Scientific. More specifically, the viscosity can be measured using parallel plates with a diameter of 35 mmφ under conditions of a gap of 0.5 mm, a temperature of 25°C, and a shear rate of 10 s ^-1 .

The viscosity of the first and second agents can be adjusted to fall within the above range by adjusting the viscosity of the matrix components, such as organopolysiloxane, contained in the first and second agents, adding components that improve the wettability of the thermally conductive filler with the matrix components, such as organopolysiloxane, or adjusting the particle size and content of the thermally conductive filler. An example of a specific composition of the first and second agents will be described below.

1.3. Voltage Resistance of Cured Product Obtained from First and Second Components The first and second components are mixed and then applied to a predetermined area for use. The first and second components initiate a curing reaction when mixed, and a cured product is obtained after a predetermined time has passed. When the two-component curing composition set of this embodiment is used in electronic devices, it is expected that the cured product and the electronic components will be placed in electrical contact. Therefore, it is preferable that the cured product obtained by mixing the first and second components has insulating properties.

More specifically, the first and second components are mixed in equal volumes, molded into a sheet, and then heat-cured at 60°C for 20 minutes. The resulting sheet has a dielectric strength measured in accordance with JIS C2110 of preferably 8 kV/mm or more, and more preferably 10 kV/mm or more. Having a dielectric strength within the above range ensures the insulating properties of the cured product. There is no particular upper limit to the dielectric strength, but the dielectric strength may be 50 kV/mm or less, for example.

The withstand voltage can be reduced by using a thermally conductive filler with low electrical conductivity or by reducing the content of the thermally conductive filler. The withstand voltage can be measured using the method described in the Examples.

1.4. Minimum Film Thickness of Cured Product Obtained from First and Second Components When a 50 N load is applied to a mixture of equal volumes of the first and second components per 10 mm x 10 mm area, the thickness of the mixture is preferably 70 to 120 μm. In this specification, the thickness of the mixture measured in this manner is defined as the minimum thickness of a film (cured product) that can be formed from the first and second components. Therefore, the minimum thickness of a film that can be formed using the two-component curing composition set of this embodiment is preferably 70 to 120 μm. When the first and second components contain a thermally conductive filler, there is a minimum film thickness that can be formed using a mixture of the first and second components, depending on the particle size and content of the thermally conductive filler. If the minimum thickness of the film is between 70 and 120 μm, a two-component curing composition set with an excellent balance of handleability and thermal conductivity tends to be obtained, even when a relatively inexpensive thermally conductive filler such as boron nitride, aluminum nitride, aluminum oxide, silicon oxide, silicon oxide, magnesium oxide, metallic aluminum, or zinc oxide, particularly aluminum oxide, is used. From the same perspective, the minimum thickness of the film is more preferably between 80 and 100 μm. The minimum thickness of the film may be measured by the method described in the Examples.

1.5. Example Compositions of the First and Second Agents In this embodiment, the first and second agents are not particularly limited as long as they are a combination that causes a curing reaction when mixed together. The reaction between the first and second agents may be a condensation reaction, an addition reaction, a radical reaction, or the like.

Combinations of first and second components that cure by a condensation reaction include, for example, a combination of a first component containing an epoxy-modified organopolysiloxane having epoxy groups and a second component containing an amino-modified organopolysiloxane having amino groups. Combinations of first and second components that cure by an addition reaction include, for example, a combination of a first component containing a vinyl-modified organopolysiloxane having vinyl groups and a second component containing a hydrosilyl-modified organopolysiloxane having hydrosilyl groups, and a combination of a first component and a second component that undergoes a Michael addition reaction.

The following describes in detail an example of the composition of the first and second components, using a combination of a vinyl-modified organopolysiloxane and a hydrosilyl-modified organopolysiloxane as an example. However, the first and second components provided in the two-component curing composition set of this embodiment are not limited to these compositions. For example, instead of a combination of a vinyl-modified organopolysiloxane and a hydrosilyl-modified organopolysiloxane, a combination of an epoxy-modified organopolysiloxane and an amino-modified organopolysiloxane may be used.

1.5.1 First Agent The first agent preferably contains a surfactant A1, a vinyl-modified organopolysiloxane B1 having a viscosity of 80 to 120 mPa·s, a thermally conductive filler C1, and an addition reaction catalyst D1. The first agent may further contain other components as necessary.

1.5.1.1. Surfactant A1
The surfactant A1 is not particularly limited as long as it can improve the wettability of the thermally conductive filler C1 with the vinyl-modified organopolysiloxane B1. From the viewpoint of further improving the wettability of the thermally conductive filler, the surfactant A1 is preferably a copolymer having at least two of an anionic group, a cationic group, and a group having a siloxane skeleton.

The anionic group is not particularly limited, but examples include a carboxy group, a phosphate group, a phenolic hydroxy group, and a sulfonic acid group. Among these, the anionic group is preferably one or more selected from the group consisting of a carboxy group, a phosphate group, and a phenolic hydroxy group, and is preferably a carboxy group.

The cationic group is not particularly limited, but examples include primary amino groups, secondary amino groups, tertiary amino groups, and quaternary ammonium cationic groups. Among these, the anionic group is preferably a tertiary amino group.

The group having a siloxane skeleton is not particularly limited, but examples include groups having an organopolysiloxane skeleton. Among these, the group having a siloxane skeleton is preferably a group having a polydimethylsiloxane skeleton.

The content of surfactant A1 is, for example, 3 to 28 parts by weight, preferably 4 to 25 parts by weight, more preferably 5 to 20 parts by weight, and even more preferably 5 to 15 parts by weight, per 100 parts by weight of vinyl-modified organopolysiloxane B1. Having the content of surfactant A1 within the above range tends to further improve the dispersibility of thermally conductive filler C1 and further reduce the viscosity of the first agent.

The weight-average molecular weight of surfactant A1 is preferably 20,000 to 150,000, more preferably 30,000 to 120,000, and even more preferably 40,000 to 100,000. Having the weight-average molecular weight of surfactant A1 within the above range tends to further improve the dispersibility of thermally conductive filler C1 and further reduce the viscosity of the first agent. The weight-average molecular weight can be determined by GPC (gel permeation chromatography).

A preferred embodiment of surfactant A1 will be described in more detail below. In this embodiment, "monomer" refers to a monomer having a polymerizable unsaturated bond before polymerization, and "monomer unit" refers to a repeating unit that constitutes part of a copolymer after polymerization and is derived from a specific monomer. Furthermore, (meth)acrylic includes acrylic and methacrylic, and (meth)acrylic monomers include (meth)acrylate and (meth)acrylamide. Furthermore, hereinafter, "(meth)acrylic monomer unit α" and the like will also be simply referred to as "monomer unit α" and the like.

Surfactant A1 is preferably a copolymer containing (meth)acrylic monomer units α having a carboxy group, (meth)acrylic monomer units β having a tertiary amino group, and (meth)acrylic monomer units γ having a siloxane skeleton. Using such a copolymer can further improve the dispersibility of thermally conductive filler C1 and tends to reduce the viscosity of the first agent.

In the above copolymer, the monomer units α, β, and γ may be contained randomly or in blocks. In surfactant A1, it is preferable that at least the monomer units α and γ are contained as a random copolymer. When the monomer units α and γ are contained as a random copolymer, the viscosity of the first agent tends to be further reduced.

1.5.1.1.1. (Meth)acrylic monomer unit α having a carboxy group
The monomer unit α is a repeating unit having a carboxy group. When the surfactant A1 has such a monomer unit, the dispersibility of the thermally conductive filler C1 tends to be further improved.

It is preferable that the monomer unit α further has an electron-withdrawing group bonded to the carboxy group. Such an electron-withdrawing group is not particularly limited, as long as it has the effect of stabilizing the negative charge on the carboxy group. For example, the monomer unit α may be a unit derived from an acrylic monomer containing an electron-withdrawing substituent, such as a halogen element, on the carbon atom at the α-position of the carboxy group. The inclusion of such a monomer unit tends to further improve the dispersibility of the thermally conductive filler C1.

It is preferable that the monomer unit α does not have an electron-donating group bonded to the carboxy group, or has a group with low electron-donating properties. Such electron-donating groups are not particularly limited, as long as they have the effect of destabilizing the negative charge on the carboxy group. For example, the monomer unit α may be a unit derived from an acrylic monomer that does not contain an electron-donating group, such as a methyl group, as a substituent on the carbon atom at the α-position of the carboxy group. The inclusion of such a monomer unit tends to further improve the dispersibility of the thermally conductive filler C1.

Such (meth)acrylic monomers are not particularly limited, but examples include acrylic acid, methacrylic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, etc. Among these, acrylic acid and 2-methacryloyloxyethyl succinic acid are preferred, and acrylic acid is more preferred. By including units derived from such monomers, affinity for the thermally conductive filler C1 is further improved, and the dispersibility of the thermally conductive filler C1 tends to be further improved. The monomer unit α may be used alone or in combination of two or more types.

The content of the monomer unit α is, for example, 0.05 to 20 parts by weight, preferably 0.08 to 6.0 parts by weight, more preferably 0.1 to 5.0 parts by weight, even more preferably 0.3 to 4.0 parts by weight, and even more preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the total of the monomer unit α, monomer unit β, and monomer unit γ. Within the above range, the content of the monomer unit α may be 0.7 parts by weight or more, or 2.0 parts by weight or less. Having the content of the monomer unit α within the above range tends to further improve the dispersibility of the thermally conductive filler C1 and further reduce the viscosity of the first agent.

1.5.1.1.2. (Meth)acrylic monomer unit β having a tertiary amino group
The monomer unit β is a repeating unit having a tertiary amino group. When the surfactant A1 has such a monomer unit, the dispersibility of the thermally conductive filler C1 tends to be further improved.

It is preferable that the monomer unit β further has an electron-donating group bonded to the carbon atom adjacent to the nitrogen atom in the tertiary amino group. Such an electron-donating group is not particularly limited as long as it has the effect of stabilizing the positive charge on the tertiary amino group. The monomer unit β may be, for example, a unit derived from an acrylic monomer containing an electron-donating substituent, such as a methyl group, on the carbon atom at the α-position of the tertiary amino group. The inclusion of such a monomer unit tends to further improve the dispersibility of the thermally conductive filler C1.

It is preferable that the monomer unit β does not have an electron-withdrawing group bonded to the carbon atom adjacent to the nitrogen atom in the tertiary amino group, or that it has a group with low electron-withdrawing properties. Such electron-withdrawing groups are not particularly limited, as long as they have the effect of destabilizing the positive charge on the tertiary amino group. The monomer unit β may be, for example, a unit derived from an acrylic monomer that does not contain a substituent of an electron-withdrawing group, such as a carboxy group, on the carbon atom at the α-position of the tertiary amino group. The inclusion of such a monomer unit tends to further improve the dispersibility of the thermally conductive filler C1.

Such (meth)acrylic monomers are not particularly limited, but examples include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate. Of these, dimethylaminoethyl methacrylate and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate are preferred, with 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate being more preferred. By including units derived from such monomers, affinity for the thermally conductive filler C1 is improved, and the dispersibility of the thermally conductive filler C1 tends to be further improved. The monomer unit β may be used alone or in combination of two or more types.

The content of the monomer unit β is, for example, 0.02 to 4.0 parts by weight, preferably 0.05 to 4.0 parts by weight, more preferably 0.07 to 3.0 parts by weight, even more preferably 0.08 to 2.0 parts by weight, and even more preferably 0.1 to 1.0 parts by weight, per 100 parts by weight of the total of the monomer unit α, monomer unit β, and monomer unit γ. Within the above range, the content of the monomer unit β may be 0.3 parts by weight or more, or 0.8 parts by weight or less. Having the content of the monomer unit β within the above range tends to further improve the dispersibility of the thermally conductive filler C1 and further reduce the viscosity of the first agent.

1.5.1.1.3. (Meth)acrylic monomer unit γ having a siloxane skeleton
The monomer unit γ is a repeating unit having a siloxane skeleton. When surfactant A1 contains such a monomer unit, the affinity or compatibility between surfactant A1 and vinyl-modified organopolysiloxane B1 increases, and the viscosity of the first agent tends to be further reduced.

The siloxane skeleton in the monomer unit γ can be, for example, an organopolysiloxane skeleton such as a dialkylpolysiloxane, a diphenylpolysiloxane, or an alkylphenylpolysiloxane. The alkyl contained in the siloxane skeleton is not particularly limited, but examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. The phenyl group contained in the siloxane skeleton is not particularly limited, but examples thereof include a phenyl group and a phenyl group having a substituent, specifically a phenyl group and a benzyl group. Examples of the substituent include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

Such (meth)acrylic monomers are not particularly limited, but examples include (meth)acrylic acid polysiloxanes in which the terminals of the siloxane skeleton are modified with (meth)acrylic acid, as described above. Specific examples include α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane. The monomer unit γ may be used alone or in combination of two or more types.

The number average molecular weight of the monomer unit γ is preferably 1,500 to 50,000, more preferably 3,000 to 30,000, and even more preferably 4,000 to 20,000. When the number average molecular weight of the monomer unit γ is 1,500 or more, the curing properties tend to be improved when the first and second agents are mixed. When the number average molecular weight of the monomer unit γ is 50,000 or less, the viscosity of the first agent tends to be further reduced. The number average molecular weight of the monomer unit γ can be determined by GPC (gel permeation chromatography).

The content of the monomer unit γ is, for example, 70.0 to 99.9 parts by weight, preferably 80.0 to 99.5 parts by weight, preferably 90.0 to 99.0 parts by weight, more preferably 93.0 to 98.8 parts by weight, and even more preferably 96.0 to 98.7 parts by weight, per 100 parts by weight of the total of the monomer unit α, monomer unit β, and monomer unit γ. Having the content of the monomer unit γ within the above range tends to further improve the dispersibility of the thermally conductive filler C1 and further reduce the viscosity of the first agent. Furthermore, curing tends to improve when the first and second agents are mixed.

The total content of monomer unit α, monomer unit β, and monomer unit γ in surfactant A1 is preferably 90% by weight or more, more preferably 95% by weight or more, even more preferably 99% by weight or more, and even more preferably 100% by weight, based on the total amount of surfactant A1. Having this total content within the above range tends to further improve the dispersibility of thermally conductive filler C1 and further reduce the viscosity of the first agent. There is no particular upper limit to the total content of monomer unit α, monomer unit β, and monomer unit γ, and it may be, for example, 100% by weight, 99% by weight, 98% by weight, or 95% by weight.

1.5.1.1.4. Production Method The production method of surfactant A1 is not particularly limited, and any known polymerization method for (meth)acrylic monomers can be used. Examples of the polymerization method include radical polymerization and anionic polymerization. Among these, radical polymerization is preferred.

Thermal polymerization initiators used in radical polymerization are not particularly limited, but examples include azo compounds such as azobisisobutyronitrile; and organic peroxides such as benzoyl peroxide, tert-butyl hydroperoxide, and di-tert-butyl peroxide. Photopolymerization initiators used in radical polymerization are also not particularly limited, but examples include benzoin derivatives. Other known polymerization initiators used in living radical polymerization, such as ATRP and RAFT, can also be used.

Polymerization conditions are not particularly limited and can be adjusted appropriately depending on the initiator and boiling point of the solvent used, as well as the type of other monomers.

The order in which the monomers are added is not particularly limited. For example, when synthesizing a random copolymer, the monomers may be mixed to initiate polymerization, and when synthesizing a block copolymer, the monomers may be added sequentially to the polymerization system.

1.5.1.2. Vinyl-modified organopolysiloxane B1
Vinyl-modified organopolysiloxane B1 (hereinafter also referred to simply as "organopolysiloxane B1") is an organopolysiloxane having a viscosity of 80 to 120 mPa·s and having at least one vinyl group. Organopolysiloxane B1 may have a vinyl group on a side chain and/or at a terminal. Such organopolysiloxane has a structural unit represented by formula (b1-1) below or a terminal structure represented by formula (b1-2). Organopolysiloxane B1 may, for example, have at least one of a structural unit represented by formula (b1-1) and a terminal structure represented by formula (b1-2), and a structural unit represented by formula (b1-3).

In formulas (b1-1), (b1-2), and (b1-3), R represents any monovalent hydrocarbon group which may have a substituent. In other words, in organopolysiloxane B1, any monovalent hydrocarbon group which may have a substituent is bonded to a side chain of the siloxane skeleton.

Such monovalent hydrocarbon groups are not particularly limited, but examples include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, 2-phenylethyl, and 2-phenylpropyl; and groups having a substituent within these groups. Substituents on the above monovalent hydrocarbon groups include, for example, halogen atoms, particularly fluorine and chlorine atoms.

Organopolysiloxane B1 is contained in the first agent either alone or in combination of two or more types. The number of vinyl groups in the organopolysiloxane B1 contained in the first agent is preferably 2.0 or more on average per molecule. That is, when the first agent contains one type of organopolysiloxane B1, it is preferable that the organopolysiloxane has two or more vinyl groups per molecule. When the first agent contains two or more types of organopolysiloxane B1, it is preferable that the arithmetic average number of vinyl groups in each organopolysiloxane is 2.0 or more. Having 2.0 or more vinyl groups per molecule tends to form a network structure when reacted with hydrosilyl-modified organopolysiloxane E2 contained in the second agent, resulting in a cured product with superior mechanical strength, such as shear displacement and elongation at break. The upper limit of the number of vinyl groups in organopolysiloxane B1 is not particularly limited, and may be, for example, an average of 4.0, 3.0, or 2.5 per molecule, and the average number of vinyl groups in organopolysiloxane B1 per molecule may be 2.0.

The average number of vinyl groups per molecule of organopolysiloxane B1 can be measured by NMR. Specifically, for example, measurement can be performed using an ECP-300NMR manufactured by JEOL, dissolving organopolysiloxane B1 in deuterated chloroform as a heavy solvent. The average number of vinyl groups per molecule can be calculated by dividing the measurement result obtained in this way by the average molecular weight of organopolysiloxane B1.

Organopolysiloxane B1 preferably contains at least an organopolysiloxane having vinyl groups at both ends. Using such an organopolysiloxane tends to make it easier to adjust the crosslink density when the first and second components are mixed. From a similar perspective, organopolysiloxane B1 preferably contains at least a polydimethylsiloxane having vinyl groups at both ends.

The viscosity of organopolysiloxane B1 at 25°C may be, for example, 30 to 300 mPa·s, but is preferably 80 to 120 mPa·s, and more preferably 90 to 110 mPa·s. If the viscosity of organopolysiloxane B1 is 300 mPa·s or less, the viscosity of the first agent tends to be lower. If the viscosity of organopolysiloxane B1 is 30 mPa·s or more, the mechanical strength of the cured product, such as the shear displacement and elongation at break, described below, tends to be improved.

In this specification, the viscosity of organopolysiloxanes at 25°C can be measured using a BROOKFIELD DV-1 digital viscometer. Using an RV spindle set and rotor No. 1, a container is used that can accommodate the rotor and be filled with organopolysiloxane up to the reference line. The rotor is immersed in the organopolysiloxane, and the viscosity is measured at 25°C and 10 rpm.

As described below, vinyl-modified organopolysiloxane B1 undergoes an addition reaction with hydrosilyl-modified organopolysiloxane E2 contained in the second part in the presence of addition reaction catalyst D1. By appropriately adjusting the number of vinyl groups and the number of hydrosilyl groups in vinyl-modified organopolysiloxane B1 and hydrosilyl-modified organopolysiloxane E2, as well as their viscosities, it is possible to control the viscosity of the first and second parts, as well as the curing speed when the first and second parts are mixed.

The content of vinyl-modified organopolysiloxane B1 is preferably 60 to 99 wt %, more preferably 70 to 98 wt %, and even more preferably 80 to 95 wt %, based on the total of all components of the first agent other than thermally conductive filler C1. Having the content of vinyl-modified organopolysiloxane B1 within the above range tends to further reduce the viscosity of the first agent.

1.5.1.3. Thermally conductive filler C1
The thermally conductive filler C1 is a filler having thermal conductivity. The thermal conductivity of the thermally conductive filler C1 is not particularly limited, but may be, for example, 10 W/m·K or more, 20 W/m·K or more, or 30 W/m·K or more. The upper limit of the thermal conductivity of the thermally conductive filler C1 is not particularly limited, and may be, for example, 400 W/m·K or 300 W/m·K. Examples of such thermally conductive fillers C1 include, but are not limited to, aluminum oxide (hereinafter also referred to as "alumina"), aluminum nitride, silica, boron nitride, silicon nitride, zinc oxide, aluminum hydroxide, metallic aluminum, magnesium oxide, diamond, carbon, indium, gallium, copper, silver, iron, nickel, gold, tin, metallic silicon, and the like.

Among these, the first agent preferably contains, as the thermally conductive filler C1, one or more selected from the group consisting of boron nitride, aluminum nitride, aluminum oxide, silicon nitride, silicon oxide, magnesium oxide, metallic aluminum, and zinc oxide; more preferably, one or more selected from the group consisting of aluminum oxide, magnesium oxide, aluminum nitride, and metallic aluminum; and even more preferably, aluminum oxide powder. This is because the above thermally conductive fillers have high thermal conductivity, high insulating properties, and are inexpensive. The thermally conductive filler C1 may be used alone or in combination of two or more types.

The average particle size of the thermally conductive filler C1 is preferably 0.05 to 120 μm, and more preferably 0.1 to 60 μm. Having the average particle size of the thermally conductive filler C1 within the above range tends to further improve the fluidity of the first agent and the dispersibility and filling ability of the thermally conductive filler C1.

Thermal conductive filler C1 may also be a mixture of fillers with different average particle sizes. It is preferable to use a combination of two or more of the following thermal conductive fillers C1: thermal conductive filler (C1-1) with an average particle size of 30 to 55 μm, thermal conductive filler (C1-2) with an average particle size of 1.5 to 25 μm, and thermal conductive filler (C1-3) with an average particle size of 0.05 to 1.0 μm. It is more preferable to use at least thermal conductive filler (C1-1) and thermal conductive filler (C1-2), and even more preferable to use all of thermal conductive filler (C1-1), thermal conductive filler (C1-2), and thermal conductive filler (C1-3).

The average particle size of thermally conductive fillers can be measured using, for example, a Shimadzu SALD-20 laser diffraction particle size analyzer. An evaluation sample is prepared by adding 50 ml of pure water and 5 g of the thermally conductive filler powder to be measured to a glass beaker, stirring with a spatula, and then dispersing in an ultrasonic cleaner for 10 minutes. The dispersed thermally conductive filler powder solution is then added dropwise to the sampler using a dropper. Measurements can be performed once the absorbance has stabilized. The laser diffraction particle size analyzer calculates the particle size distribution from the light intensity distribution data of the diffraction/scattering holes detected by the sensor. The average particle size is calculated by multiplying the measured particle size value by the relative particle amount (difference %) and dividing by the total relative particle amount (100%). The average particle size is the average diameter of particles and can be calculated as the cumulative weight average D50 (median diameter). D50 is the particle size with the highest occurrence rate.

In this case, the content of the thermally conductive filler (C1-1) is preferably 30 to 70% by weight, more preferably 40 to 60% by weight, based on the total amount of the thermally conductive filler C1.
The content of the thermally conductive filler (C1-2) is preferably 10 to 50% by weight, more preferably 20 to 40% by weight, based on the total amount of the thermally conductive filler C1.
The content of the thermally conductive filler (C1-3) is preferably 5 to 30% by weight, more preferably 10 to 20% by weight, based on the total amount of the thermally conductive filler C1.
By using the thermally conductive filler C1 as described above, the fluidity of the first agent and the dispersibility and filling property of the thermally conductive filler C1 tend to be further improved. Note that the average particle size in this specification means D50 (median diameter).

The content of thermally conductive filler C1 is, for example, 400 to 3000 parts by weight, preferably 1500 to 2400 parts by weight, and more preferably 1700 to 2200 parts by weight, per 100 parts by weight of vinyl-modified organopolysiloxane B1. When the content of thermally conductive filler C1 is 400 parts by weight or more, the thermal conductivity of the resulting cured product tends to be further improved, while when it is 3000 parts by weight or less, the viscosity of the first agent tends to be further reduced.

1.5.1.4. Addition reaction catalyst D1
The addition reaction catalyst D1 is not particularly limited as long as it catalyzes the addition reaction between the vinyl-modified organopolysiloxane B1 and the hydrosilyl-modified organopolysiloxane E2. Examples of the addition reaction catalyst D1 include platinum compound catalysts, rhodium compound catalysts, and palladium compound catalysts. Among these, platinum compound catalysts are preferred. Use of such an addition reaction catalyst D1 tends to ensure that the curing rate when the first and second parts are mixed can be within a suitable range.

Platinum compound catalysts include, but are not limited to, platinum alone, platinum compounds, and platinum-supported inorganic powders. Platinum compounds include, but are not limited to, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. Platinum-supported inorganic powders include, but are not limited to, platinum-supported alumina powder, platinum-supported silica powder, and platinum-supported carbon powder.

Addition reaction catalyst D1 may be used alone or in combination with two or more different types. Furthermore, when preparing the first agent, addition reaction catalyst D1 may be blended alone, or may be blended in a premix with other components, such as vinyl-modified organopolysiloxane B1 or other organopolysiloxanes.

The content of addition reaction catalyst D1 is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, and even more preferably 1 to 10 parts by weight, per 100 parts by weight of vinyl-modified organopolysiloxane B1. Having the content of addition reaction catalyst D1 within this range tends to ensure that the curing speed when the first and second parts are mixed falls within a suitable range.

1.5.1.5. Other Components In addition to the above components, the first agent may contain additives such as colorants and reaction retarders, if necessary.

If the first agent contains a colorant, the content of the colorant is preferably 0.001 to 0.2 parts by weight per 100 parts by weight of the total amount of the first agent.

The reaction retarder is not particularly limited as long as it is a component that delays the reaction when the first and second agents are mixed, but examples include alkenyl alcohols, of which 1-ethynyl-1-cyclohexanol is preferred. When the first agent contains a reaction retarder, the content of the reaction retarder is preferably 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the vinyl-modified organopolysiloxane B1. The reaction retarder may not be contained in the first agent, but may be contained only in the second agent.

The first agent is a compound of the following formula:
R ¹ _a R ² _b Si(OR ³ ) _4-(a+b)
( ^Each R1 is independently an alkyl group having 1 to 15 carbon atoms, ^each R2 is independently a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms, each ^R3 is independently an alkyl group having 1 to 6 carbon atoms, a is 1 to 3, b is 0 to 2, and a+b is 1 to 3.)
It is preferred that the organosilane does not contain an organosilane represented by the formula:

Such organosilanes have traditionally been used to improve the wettability of thermally conductive fillers, but are preferably not included in the first part of the two-part curing composition set of this embodiment. In this embodiment, the viscosity of the first part tends to be even lower than when the above-mentioned organosilanes are included. The reason for this is not entirely clear, but it is thought that when the first part contains an organosilane, the surfactant A1 and the organosilane compete with each other as components for improving the wettability of thermally conductive fillers, thereby reducing the effect of the surfactant A1.

R ¹ in the above formula is not particularly limited, but examples thereof include a methyl group, an ethyl group, a propyl group, a hexyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, etc. Among these, R ¹ is preferably an alkyl group having 6 to 12 carbon atoms.

^R2 in the above formula is not particularly limited, but examples thereof include alkyl groups such as methyl, ethyl, propyl, hexyl, and octyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl and tolyl; aralkyl groups such as 2-phenylethyl and 2-methyl-2-phenylethyl; and halogenated hydrocarbon groups such as 3,3,3-trifluoropropyl, 2-(perfluorobutyl)ethyl, 2-(perfluorooctyl)ethyl, and p-chlorophenyl.

^R3 in the above formula is not particularly limited, but is, for example, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group, and is preferably a methyl group or an ethyl group.

In the above formula, a is an integer from 1 to 3, preferably 1. Also, b is an integer from 0 to 2, preferably 0. Furthermore, a+b is an integer from 1 to 3, preferably 1.

The content of the above organosilane in the first agent is preferably 1 part by weight or less, more preferably 0.1 part by weight or less, even more preferably 0.01 part by weight or less, and particularly preferably 0 part by weight (i.e., no organosilane) per 100 parts by weight of the thermally conductive filler C1. Having the organosilane content within the above range tends to effectively improve the wettability of the thermally conductive filler.

1.5.2 Second Agent The second agent preferably contains a surfactant A2, a vinyl-modified organopolysiloxane B2 having a viscosity of 80 to 120 mPa s, a thermally conductive filler C2, and a hydrosilyl-modified organopolysiloxane E2 having a viscosity of 1 to 100 mPa s. The second agent may contain other components as necessary.

1.5.2.1. Surfactant A2
Specific examples and preferred embodiments of surfactant A2 are the same as those of surfactant A1 contained in the first agent, and therefore redundant explanations will be omitted. Surfactant A1 contained in the first agent and surfactant A2 contained in the second agent may be the same or different.

In the second agent, the content of surfactant A2 is, for example, 3 to 28 parts by weight, preferably 4 to 25 parts by weight, more preferably 5 to 20 parts by weight, and even more preferably 5 to 15 parts by weight, per 100 parts by weight of the total of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2. Having the content of surfactant A2 within the above range tends to further improve the dispersibility of thermally conductive filler C2 and further reduce the viscosity of the second agent.

1.5.2.2. Vinyl-modified organopolysiloxane B2
Specific examples and preferred embodiments of the vinyl-modified organopolysiloxane B2 are similar to those of the vinyl-modified organopolysiloxane B1 contained in the first agent, and therefore redundant explanations will be omitted. The vinyl-modified organopolysiloxane B1 contained in the first agent and the vinyl-modified organopolysiloxane B2 contained in the second agent may be the same or different.

In the second agent, the content of vinyl-modified organopolysiloxane B2 is preferably 30 to 98 parts by weight, more preferably 40 to 95 parts by weight, and even more preferably 45 to 93 parts by weight, per 100 parts by weight of the total of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2. Having the content of vinyl-modified organopolysiloxane B2 within the above range tends to ensure a more favorable curing rate when the first and second agents are mixed. Within the above range, the content of vinyl-modified organopolysiloxane B2 may be 90 parts by weight or less, 80 parts by weight or less, or 70 parts by weight or less.

1.5.2.3. Thermally conductive filler C2
Specific examples and preferred embodiments of the thermally conductive filler C2 are the same as those of the thermally conductive filler C1 contained in the first agent, and therefore, redundant explanations will be omitted. The thermally conductive filler C1 contained in the first agent and the thermally conductive filler C2 contained in the second agent may be the same or different.

The content of thermally conductive filler C2 is, for example, 400 to 3,000 parts by weight, preferably 1,500 to 2,400 parts by weight, and more preferably 1,700 to 2,200 parts by weight, per 100 parts by weight of the combined total of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2. When the content of thermally conductive filler C2 is 400 parts by weight or more, the thermal conductivity of the resulting cured product tends to be further improved, while when it is 3,000 parts by weight or less, the viscosity of the second agent tends to be further reduced.

1.5.2.4. Hydrosilyl-modified organopolysiloxane E2
Hydrosilyl-modified organopolysiloxane E2 (hereinafter also referred to simply as "organopolysiloxane E2") is an organopolysiloxane having a viscosity of 1 to 100 mPa·s and having at least one hydrosilyl group. Organopolysiloxane E2 may have a hydrosilyl group on a side chain and/or at a terminal. Such organopolysiloxane has a structural unit represented by the following formula (e2-1) or a terminal structure represented by formula (e2-2). Organopolysiloxane E2 may have, for example, at least one of the structural unit represented by formula (e2-1) and the terminal structure represented by formula (e2-2), and a structural unit represented by formula (e2-3).

In formulas (e2-1), (e2-2), and (e2-3), R represents any monovalent hydrocarbon group which may have a substituent. That is, in organopolysiloxane E2, any monovalent hydrocarbon group which may have a substituent is bonded to a side chain of the siloxane skeleton.

Such monovalent hydrocarbon groups include the same monovalent hydrocarbon groups that may be contained in vinyl-modified organopolysiloxane B1.

The viscosity of organopolysiloxane E2 at 25°C is 1 to 100 mPa·s, preferably 2 to 80 mPa·s, and more preferably 3 to 50 mPa·s. If the viscosity of organopolysiloxane E2 is 100 mPa·s or less, the viscosity of the second agent tends to be lower. If the viscosity of organopolysiloxane E2 is 1 mPa·s or more, the mechanical strength of the cured product, such as the shear displacement and elongation at break, described below, tends to be improved. Note that if organopolysiloxane E2 contains multiple components, it is preferable that the above viscosity values be satisfied for each of those multiple components.

Organopolysiloxane E2 is contained in the second agent either alone or in combination of two or more types. For example, it is preferable that the second agent contains at least hydrosilyl-modified organopolysiloxane E22, which has hydrosilyl groups on its side chains, as organopolysiloxane E2. It is even more preferable that the second agent contain hydrosilyl-modified organopolysiloxane E21, which has hydrosilyl groups on both ends, and the above-mentioned hydrosilyl-modified organopolysiloxane E22.

Organopolysiloxane E21 has at least two hydrosilyl groups at both ends of the organopolysiloxane backbone. Organopolysiloxane E21 may further have hydrosilyl groups on side chains. Organopolysiloxane E21 may be an organopolysiloxane having hydrosilyl groups only at both ends.

Organopolysiloxane E22 has at least one hydrogen atom in a side chain of the organopolysiloxane backbone, and this hydrogen atom and a silicon atom constitute a hydrosilyl group. Organopolysiloxane E22 may further have hydrosilyl groups at both ends of the organopolysiloxane backbone. The number of hydrosilyl groups in organopolysiloxane E22 is preferably greater than 2.0 on average per molecule, more preferably 2.5 or more on average per molecule, and even more preferably 3.0 or more on average per molecule. There is no particular upper limit to the number of hydrosilyl groups in organopolysiloxane E22, and it may be, for example, 8.0, 6.0, or 5.0 on average per molecule.

The number of hydrosilyl groups in the organopolysiloxane E2 contained in the second agent preferably exceeds 2.0 on average per molecule, and more preferably exceeds 2.5 on average per molecule. That is, when the second agent contains one type of organopolysiloxane E2, it is preferable that the organopolysiloxane has more than two (i.e., three or more) hydrosilyl groups per molecule. When the second agent contains two or more types of organopolysiloxane E2, it is preferable that the arithmetic average number of hydrosilyl groups in each organopolysiloxane exceeds 2.0.

As described above, the number of hydrosilyl groups in organopolysiloxane E21 and organopolysiloxane E22 can be controlled separately. Therefore, by appropriately mixing the two, it is possible to control the viscosity of the second part while also controlling its reactivity with the first part. In particular, when the second part contains organopolysiloxane E22, it tends to form a network structure when reacted with vinyl-modified organopolysiloxanes B1 and B2, resulting in a cured product with superior mechanical strength, such as shear displacement and elongation at break.

The average number of hydrosilyl groups per molecule of organopolysiloxane E2 can be measured by NMR. Specifically, for example, measurement can be performed using an ECP-300NMR (manufactured by JEOL) with organopolysiloxane E2 dissolved in deuterated chloroform as a heavy solvent. The average number of hydrosilyl groups per molecule can be calculated by dividing the measurement result obtained in this way by the average molecular weight of organopolysiloxane E2.

The viscosity of organopolysiloxane E21 at 25°C is preferably 5 to 100 mPa·s, more preferably 10 to 80 mPa·s, and even more preferably 15 to 50 mPa·s. If the viscosity of organopolysiloxane E21 is 100 mPa·s or less, the viscosity of the second part tends to be lower. If the viscosity of organopolysiloxane E21 is 5 mPa·s or more, the mechanical strength of the cured product, such as the shear displacement and elongation at break, described below, tends to be improved.

The viscosity of organopolysiloxane E22 at 25°C is preferably 1 to 100 mPa·s, more preferably 2 to 90 mPa·s, and even more preferably 3 to 80 mPa·s. When the viscosity of organopolysiloxane E22 is 100 mPa·s or less, the viscosity of the second agent tends to be further reduced. When the viscosity of organopolysiloxane E22 is 1 mPa·s or more, the mechanical strength of the cured product, such as the shear displacement and elongation at break, described below, tends to be further improved. The viscosity of organopolysiloxane E22 at 25°C may be 50 mPa·s or less, or 20 mPa·s or less, within the above range. Alternatively, in another aspect, the viscosity of organopolysiloxane E22 at 25°C may be 60 to 80 mPa·s, within the above range.

In the second agent, the content of hydrosilyl-modified organopolysiloxane E2 is preferably 2 to 70 parts by weight, more preferably 5 to 60 parts by weight, and even more preferably 7 to 55 parts by weight, per 100 parts by weight of the total of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2. Having the content of hydrosilyl-modified organopolysiloxane E2 within the above range tends to ensure a more favorable curing rate when the first and second agents are mixed. Within the above range, the content of hydrosilyl-modified organopolysiloxane E2 may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more.

The total content of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2 is preferably 60 to 99% by weight, more preferably 70 to 98% by weight, and even more preferably 80 to 95% by weight, based on the total components of the second part other than thermally conductive filler C1. Having this content within the above range tends to further reduce the viscosity of the second part and keep the curing speed within a more suitable range when the first and second parts are mixed.

1.5.2.5. Reaction retarder F2
The reaction retarder F2 is an additive that is optionally added to control the reaction between the hydrosilyl group and the vinylsilyl group. In this embodiment, it is preferable that the first part contains the addition reaction catalyst D1, and the second part contains a reaction retarder. The reaction retarder F2 is not particularly limited as long as it is a component that delays the reaction when the first part and the second part are mixed, but examples include alkenyl alcohols, and 1-ethynyl-1-cyclohexanol is particularly preferred. The use of such a reaction retarder F2 tends to make it possible to keep the curing rate when the first part and the second part are mixed within a suitable range.

When the second part contains reaction retarder F2, the content of reaction retarder F2 is preferably 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of vinyl-modified organopolysiloxane B2 and hydrosilyl-modified organopolysiloxane E2. Having the content of reaction retarder F2 within this range tends to ensure that the curing speed when the first and second parts are mixed can be kept within a suitable range.

1.5.2.6. Other Components In addition to the above components, the second agent may contain additives such as colorants, if necessary. Specific examples, preferred embodiments, content, and other details of the colorants are the same as those of the first agent, and redundant explanations will be omitted. The additives contained in the first agent and the additives contained in the second agent may be the same or different.

The second agent is a compound of the following formula:
R ¹ _a R ² _b Si(OR ³ ) _4-(a+b)
( ^Each R1 is independently an alkyl group having 1 to 15 carbon atoms, ^each R2 is independently a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms, each ^R3 is independently an alkyl group having 1 to 6 carbon atoms, a is 1 to 3, b is 0 to 2, and a+b is 1 to 3.)
It is preferable that the second agent does not contain an organosilane represented by the following formula: By not containing the above organosilane, the viscosity of the second agent tends to be further reduced.

Specific aspects of the organosilanes mentioned above are the same as those of the organosilanes that are preferably not contained in the first agent. The preferred content of the organosilanes mentioned above in the second agent is also the same as that in the first agent.

1.6. Uses The two-component curing composition set of the present embodiment can be suitably used as a thermally conductive heat-dissipating material such as thermally conductive grease.

2. Cured Product The cured product of this embodiment is obtained by mixing the first and second parts of the two-component curing composition set described above. More specifically, the cured product (crosslinked cured product) is obtained by mixing the first and second parts and subjecting two or more reactive groups to an addition reaction, condensation reaction, radical reaction, or the like in the mixture obtained. In one aspect of the present embodiment described above, in which the first part contains a vinyl-modified organopolysiloxane and the second part contains a vinyl-modified organopolysiloxane and a hydrosilyl-modified organopolysiloxane, the cured product is obtained by an addition reaction between the vinyl groups of the vinyl-modified organopolysiloxanes B1 and B2 and the hydrosilyl groups of the hydrosilyl-modified organopolysiloxane E2.

After mixing the first and second parts, the mixture can be molded into the desired shape before curing to obtain a cured product with the desired shape. Furthermore, because the cured product of this embodiment contains a thermally conductive filler, it can be suitably used as a thermally conductive heat dissipation material.

To mix the first and second components, mixers such as a roll mill, kneader, Banbury mixer, or line mixer are used. More specifically, examples include kneading methods using a universal mixer, hybrid mixer, Trimix (manufactured by Inoue Seisakusho), or static mixer. The preferred molding method is the doctor blade method, but extrusion, pressing, or calendar roll methods may also be used depending on the viscosity of the resin. The reaction conditions for the addition reaction are not particularly limited, but are typically carried out at room temperature (e.g., 25°C) to 150°C for 0.1 to 24 hours.

The mixing ratio of the first and second agents can be set appropriately depending on the type of first and second agents used and the intended use, but for example, the volume ratio of first agent:second agent may be 1.5:1.0 to 1.0:1.5, or may be 1.0:1.0.

3. Electronic Device The electronic device of this embodiment includes an electronic component, a cured product, and a heat sink, and the electronic component and the heat sink are in contact with each other via the cured product.

Here, examples of electronic components that generate heat include, but are not limited to, motors, battery packs, circuit boards mounted on automotive power supply systems, power transistors, microprocessors, and other electronic components that do not generate heat. Furthermore, examples of heat sinks that generate heat include, but are not limited to, housings, particularly metal housings.

The present invention will be further described in detail below using examples, but the present invention is not limited to the following examples.

1. Synthesis of surfactant 1.1. Raw material ((meth)acrylic monomer α having a carboxy group)
Acrylic acid, manufactured by Toagosei

((Meth)acrylic monomer β having a tertiary amino group)
1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, "ADEKA STAB LA-82" manufactured by ADEKA Corporation

((Meth)acrylic monomer γ having a siloxane skeleton)
(γ-1) α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane), JNC Corporation "Silaplane FM-0725", number average molecular weight 10,000
(γ-2) α-butyl-ω-(3-methacryloxypropyl) polydimethylsiloxane), JNC Corporation "Silaplane FM-0721", number average molecular weight 5000
(γ-3) α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane), JNC Corporation "Silaplane FM-0711", number average molecular weight 1000

1.2. Surfactant 1
Surfactant 1 was synthesized as follows. First, 1.5 parts by weight of acrylic acid, 0.5 parts by weight of 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and 98.0 parts by weight of α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane (γ-1) were added to an autoclave equipped with a stirrer. Next, 0.05 parts by weight of azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as an initiator relative to 100 parts by weight of the total (meth)acrylic monomers, and 1,000 parts by weight of a mixed solution of toluene (special reagent grade) and isopropyl alcohol (special reagent grade) in a volume ratio of 7:3 was added as a solvent, and the atmosphere inside the autoclave was replaced with nitrogen. Thereafter, the autoclave was heated in an oil bath at 65°C for 20 hours to carry out radical polymerization. After completion of polymerization, the mixture was degassed under reduced pressure at 120°C for 1 hour to obtain Surfactant 1.

The polymerization rate, based on 100% of the monomer charge, was determined by gas chromatography to be over 98%. From this, it was estimated that the ratio of each monomer unit in the surfactant was approximately the same as the monomer charge ratio.

The weight-average molecular weight of the resulting surfactant 1 was determined as a weight-average molecular weight converted into standard polystyrene using GPC (gel permeation chromatography) under the following measurement conditions:
High-speed GPC device: Tosoh Corporation "HLC-8020"
Column: One "TSK guard column MP (xL)" manufactured by Tosoh Corporation, 6.0 mm ID x 4.0 cm, and two "TSK-GELMULTIPORE HXL-M" manufactured by Tosoh Corporation, 7.8 mm ID x 30.0 cm (theoretical plate number: 16,000), for a total of three (total theoretical plate number: 32,000)
Developing solvent: Tetrahydrofuran Detector: RI (differential refractometer)

1.3. Surfactants 2 to 14
Using the composition ratios of the (meth)acrylic monomers shown in Table 1, surfactants 2 to 14 were obtained by radical polymerization in the same manner as surfactant 1, except that the mixing ratio of toluene and isopropyl alcohol was adjusted to control the solubility of the monomers and the weight-average molecular weight of the surfactant. The polymerization rates of the obtained surfactants 2 to 14 were all 98% or higher, and the ratios of the monomer units contained in the surfactants were estimated to be approximately the same as the monomer charging ratios. The weight-average molecular weights were also determined in the same manner as above.

In Table 1, the monomer composition is shown in weight percent. The weight ratio of α-butyl-ω-(3-methacryloxypropyl)polydimethylsiloxane was calculated based on its number average molecular weight.

2. Preparation of First Agent First agents I-1 to I-30 were prepared by mixing components A1 to D1 shown below in the compounding ratios (parts by weight) shown in Table 2. The components were mixed using a hybrid mixer ARE-310 (trade name, manufactured by Thinky Corporation).

[A1: Surfactant]
A1-1 to A1-14: Surfactants 1 to 14 obtained by the above synthesis method
(A1-1 to A1-14 correspond to surfactants 1 to 14, respectively.)
A1-15: Z6210 (trade name, manufactured by Dow Toray Co., Ltd.), n-decyltrimethoxysilane

[B1: Vinyl-modified organopolysiloxane]
B1-1: RH-Vi100E (trade name, manufactured by Runhe Chemical Industry), vinyl-modified organopolysiloxane, viscosity at 25°C: 105 mPa·s, average number of vinyl groups per molecule: 2, linear structure, vinyl group bonding positions: both terminals B1-2: 621V100 (trade name, manufactured by Elkem Silicones), vinyl-modified organopolysiloxane, viscosity at 25°C: 100 mPa·s, average number of vinyl groups per molecule: 2, linear structure, vinyl group bonding positions: both terminals B1-3: SE1885A (trade name, manufactured by Dow Chemical Japan), vinyl-modified organopolysiloxane, viscosity at 25°C: 500 mPa·s

[C1: Thermally conductive filler]
C1-1: DAW45S (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 45 μm, thermal conductivity: 35 W/m·K
C1-2: DAW05 (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 5 μm, thermal conductivity: 35 W/m·K
C1-3: ASFP40 (trade name, manufactured by Denka Co., Ltd.), ultrafine alumina, average particle size: 0.4 μm, thermal conductivity: 35 W/m·K
C1-4: DMG60 (trade name, manufactured by Denka Co., Ltd.), magnesium oxide, average particle size: 60 μm, thermal conductivity 60 W/m·K
C1-5: AN-HF50LG (product name, manufactured by Combustion Synthesis Co., Ltd.), aluminum nitride, average particle size: 50 μm, thermal conductivity: 170 W/m·K
C1-6: Al-63 μm (product name, manufactured by Hikari Materials Industry Co., Ltd.), metallic aluminum, average particle size: 63 μm, thermal conductivity 240 W/m·K
C1-7: DAW70 (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 70 μm, thermal conductivity: 35 W/m·K

[D1: Addition reaction catalyst]
D1-1: Platinum complex polymethylvinylsiloxane solution (manufactured by Blue Star Silicone, product name: Silicolyse Catalyst 12070)

3. Preparation of Second Agent Components A2 to C2, E2, and F2 shown below were mixed according to the blending ratios (parts by weight) shown in Table 3 to prepare second agents II-1 to II-34. The components were mixed using a hybrid mixer ARE-310 (trade name, manufactured by Thinky Corporation).

[A2: Surfactant]
A2-1 to A2-14: Surfactants 1 to 14 obtained by the above synthesis method
(A2-1 to A2-14 correspond to surfactants 1 to 14, respectively.)
A2-15: Z6210 (trade name, manufactured by Dow Toray Co., Ltd.), n-decyltrimethoxysilane

[B2: Vinyl-modified organopolysiloxane]
B2-1: RH-Vi100E (trade name, manufactured by Runhe Chemical Industry), vinyl-modified organopolysiloxane, viscosity at 25°C: 105 mPa·s, average number of vinyl groups per molecule: 2, linear structure, vinyl group bonding positions: both terminals B2-2: 621V100 (trade name, manufactured by Elkem Silicones), vinyl-modified organopolysiloxane, viscosity at 25°C: 100 mPa·s, average number of vinyl groups per molecule: 2, linear structure, vinyl group bonding positions: both terminals

[C2: Thermally conductive filler]
C2-1: DAW45S (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 45 μm, thermal conductivity: 35 W/m·K
C2-2: DAW05 (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 5 μm, thermal conductivity: 35 W/m·K
C2-3: ASFP40 (trade name, manufactured by Denka Co., Ltd.), ultrafine alumina, average particle size: 0.4 μm, thermal conductivity: 35 W/m·K
C2-4: DMG60 (trade name, manufactured by Denka Co., Ltd.), magnesium oxide, average particle size: 60 μm, thermal conductivity 60 W/m·K
C2-5: AN-HF50LG (product name, manufactured by Combustion Synthesis Co., Ltd.), aluminum nitride, average particle size: 50 μm, thermal conductivity: 170 W/m·K
C2-6: Al-63 μm (product name, manufactured by Hikari Materials Industry Co., Ltd.), metallic aluminum, average particle size: 63 μm, thermal conductivity 240 W/m·K
C2-7: DAW70 (trade name, manufactured by Denka Co., Ltd.), spherical alumina, average particle size: 70 μm, thermal conductivity: 35 W/m·K

[E2: Hydrosilyl-modified organopolysiloxane]
E2-1: RH-LHC-3 (manufactured by Runhe Chemical Industry, trade name), hydrosilyl-modified organopolysiloxane, viscosity at 25°C: 5 mPa s, average number of hydrosilyl groups per molecule: 3 or more, linear structure, hydrosilyl group bonding position: side chain E2-2: 626V30H2.5 (manufactured by Elkem, trade name), hydrosilyl-modified organopolysiloxane, viscosity at 25°C: 30 mPa s, average number of hydrosilyl groups per molecule: 3 or more, linear structure, hydrosilyl group bonding position: both terminals and side chain E2-3: RH-H45 (manufactured by Runhe Chemical Industry, trade name), hydrosilyl-modified organopolysiloxane, viscosity at 25°C: 20 mPa s, average number of hydrosilyl groups per molecule: 2, linear structure, hydrosilyl group bonding position: both terminals E2-4: 620V20 (trade name, manufactured by Elkem), hydrosilyl-modified organopolysiloxane, viscosity at 25°C: 20 mPa·s, average number of hydrosilyl groups per molecule: 2, linear structure, hydrosilyl group bonding position: both terminals. E2-5: SE1885B (trade name, manufactured by Dow Chemical Japan), mixture of vinyl-modified organopolysiloxane and hydrosilyl-modified organopolysiloxane, viscosity at 25°C: 350 mPa·s.

[F2: Reaction retarder]
F2-1: PA90 (trade name, manufactured by Elkem), a mixture of 1-ethynyl-1-cyclohexanol, polyorganosiloxane, and filler

4. Properties of the first and second agents (viscosity)
The viscosity of the first and second parts at 25°C and a shear rate of 10 s ^-1 was measured using a rotational rheometer "HANKE MARSIII" manufactured by Thermo Fisher Scientific. Specifically, measurements were performed using parallel plates with a diameter of 35 mm, with a gap of 0.5 mm, at a temperature of 25°C, and a shear rate of 10 s ^-1 . The results are shown in Table 4.

(Thermal resistance and thermal conductivity)
The thermal resistance and thermal conductivity of the first and second parts were measured using a resin material thermal resistance measuring device manufactured by Hitachi Technology Co., Ltd. according to a method in accordance with ASTM D5470.

Specifically, the first and second agents were applied to a measurement area of 10 mm x 10 mm at thicknesses of 0.2 mm, 0.5 mm, and 1.0 mm, and the thermal resistance values of each were measured.

The thermal conductivity of the first and second components was then calculated by calculating the slope of the line obtained by plotting the thermal resistance value on the vertical axis and the thickness of the first and second components on the horizontal axis. The measurement results for thermal resistance and thermal conductivity are shown in Table 4.

5. Mixability of First and Second Components The first and second components were mixed in a volume ratio of 1:1 in the combinations shown in Table 4, and the handleability of each first and second component was evaluated. Specifically, the first and second components were placed in a 50 ml (1:1) cartridge in the combination shown in Table 4, the cartridge was capped, and the cartridge was attached to a dispenser gun (product name "MixPac DMA50"), and a mixer (9.5 cm long, 12 blades) for mixing the first and second components was attached to the cartridge's outlet, and the components were mixed and dispensed at a volume ratio of 1:1. As a result, the two-component curing composition sets of the examples, in which the viscosities of the first and second components, as measured independently with a rotational rheometer, were 50 to 120 Pa s, exhibited good ejection properties and excellent handleability, and cured products could be easily formed. On the other hand, the two-component curing composition sets of Comparative Examples 7, 15, 18, 19, 26, 27, and 29 to 34, in which the viscosity of the first part and/or second part exceeded 120 Pa·s, had poor ejection properties and insufficient handleability.

Furthermore, from the two-component curing composition sets of the Examples in which the thermal resistance values at a thickness of 1.0 mm, measured by a method in accordance with ASTM D5470, of the first and second parts were each independently 1.4 to 2.1 ^cm2 ·°C/W, cured products with excellent thermal conductivity were obtained, as shown in Table 4. On the other hand, the cured product obtained from the two-component curing composition set of Comparative Example 14, in which the thermal resistance value of the first and/or second parts exceeded 2.1 ^cm2 ·°C/W, did not have sufficient thermal conductivity, as shown in Table 4. Note that cured products with a thermal conductivity of 4.7 W/m·K or higher were rated as having excellent thermal conductivity, and those with a thermal conductivity of less than 4.7 W/m·K were rated as having poor thermal conductivity.

(Voltage resistance)
The first and second components were mixed in a volume ratio of 1:1 in the combinations shown in Table 4, and the resulting mixture was molded into a sheet and then heat-cured at 60°C for 20 minutes to obtain a thermally conductive sheet. The breakdown voltage (withstand voltage) of this thermally conductive sheet was measured using a withstand voltage tester TOS5101 manufactured by Kikusui Electronics Co., Ltd. in accordance with JIS C2110. The measurement results are shown in Table 4.

(Minimum thickness of film that can be formed)
The first and second components were mixed in a 1:1 volume ratio in the combinations shown in Table 4, and the resulting mixture was applied to the measurement surface of a resin material thermal resistance measuring device manufactured by Hitachi Technologies, Ltd., and a load of 50 N was applied to a measurement area of 10 mm x 10 mm. The thickness of the mixture at this time was taken as the minimum thickness of the film that could be formed. The measurement results are shown in Table 4.

The two-component curing composition set of this embodiment has industrial applicability as a thermally conductive cured product, particularly as a material for thermally bonding a heating element and a heat sink, by mixing and curing the first and second parts.

Claims (18)

A first agent and a second agent are provided,
the first part and the second part each independently have a thermal resistance value at a thickness of 1.0 mm, as measured by a method in accordance with ASTM D5470, of 1.4 to 2.1 ^cm2 ·°C/W;
the first agent and the second agent each independently have a viscosity of 50 to 120 Pa s as measured by a rotational rheometer;
the first agent comprises a surfactant A1, a vinyl-modified organopolysiloxane B1 having a viscosity of 80 to 120 mPa·s, a thermally conductive filler C1, and an addition reaction catalyst D1;
the second agent comprises a surfactant A2, a vinyl-modified organopolysiloxane B2 having a viscosity of 80 to 120 mPa·s, a thermally conductive filler C2, and a hydrosilyl-modified organopolysiloxane E2 having a viscosity of 1 to 100 mPa·s ;
Two-component curing composition set. the vinyl-modified organopolysiloxane B1 and the vinyl-modified organopolysiloxane B2 each independently have an average of 2.0 or more vinyl groups per molecule,
The hydrosilyl-modified organopolysiloxane E2 has an average of more than 2.0 hydrosilyl groups per molecule.
The two-component curing composition set according to claim 1 . In the first agent, the amount of the vinyl-modified organopolysiloxane B1 is 100 parts by weight.
The content of the surfactant A1 is 5 to 25 parts by weight,
The content of the thermally conductive filler C1 is 1500 to 2400 parts by weight.
The two-component curing composition set according to claim 1 . In the second agent, for a total of 100 parts by weight of the vinyl-modified organopolysiloxane B2 and the hydrosilyl-modified organopolysiloxane E2,
The content of the surfactant A2 is 5 to 25 parts by weight,
The content of the thermally conductive filler C2 is 1500 to 2400 parts by weight.
The two-component curing composition set according to claim 1 . The surfactant A1 and the surfactant A2 are copolymers having (meth)acrylic monomer units α having a carboxy group, (meth)acrylic monomer units β having a tertiary amino group, and (meth)acrylic monomer units γ having a siloxane skeleton.
The two-component curing composition set according to claim 1 . The number average molecular weight of the monomer unit γ is 1,500 to 50,000.
The two-component curing composition set according to claim 5 . In the copolymer, relative to 100 parts by weight in total of the monomer units α, β, and γ,
the content of the monomer unit α is 0.08 to 6.0 parts by weight,
the content of the monomer unit β is 0.02 to 4.0 parts by weight,
the content of the monomer unit γ is 90.0 to 99.9 parts by weight;
The two-component curing composition set according to claim 5 . The surfactant A1 and the surfactant A2 each independently have a weight average molecular weight of 20,000 to 150,000.
The two-component curing composition set according to claim 1 . The hydrosilyl-modified organopolysiloxane E2 comprises a hydrosilyl-modified organopolysiloxane E21 having hydrosilyl groups at both ends and a hydrosilyl-modified organopolysiloxane E22 having hydrosilyl groups in side chains.
The two-component curing composition set according to claim 1 . The thermally conductive filler C1 and the thermally conductive filler C2 are each independently one or more selected from the group consisting of boron nitride, aluminum nitride, aluminum oxide, silicon nitride, silicon oxide, magnesium oxide, metallic aluminum, and zinc oxide.
The two-component curing composition set according to claim 1 . The thermally conductive filler C1 and the thermally conductive filler C2 contain aluminum oxide powder.
The two-component curing composition set according to claim 10 . the first agent and the second agent are mixed in equal volumes, molded into a sheet, and then heat-cured at 60°C for 20 minutes, resulting in a sheet having a withstand voltage of 8 kV/mm or more as measured in accordance with JIS C2110;
The two-component curing composition set according to claim 1 . The thickness of the mixture when a load of 50 N is applied per 10 mm x 10 mm area to a mixture obtained by mixing the first agent and the second agent in equal volumes is 70 to 120 μm.
The two-component curing composition set according to claim 1 . The first agent and the second agent are represented by the following formula:
R ¹ _a R ² _b Si(OR ³ ) _4-(a+b)
( ^Each R1 is independently an alkyl group having 1 to 15 carbon atoms, ^each R2 is independently a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms, each ^R3 is independently an alkyl group having 1 to 6 carbon atoms, a is 1 to 3, b is 0 to 2, and a+b is 1 to 3.)
does not contain organosilane represented by
The two-component curing composition set according to claim 1 . Used as a thermally conductive heat dissipation material,
The two-component curing composition set according to any one of claims 1 to 14 . The two-component curing composition set according to any one of claims 1 to 14 , wherein the first component and the second component are mixed together.
cured product. Used as a thermally conductive heat dissipation material,
The cured product according to claim 16 . An electronic component, the cured product according to claim 17 , and a heat sink,
the electronic component and the heat sink are in contact with each other via the cured product.
electronic equipment.