CN115612300A

CN115612300A - Heat-conducting gasket and preparation method thereof

Info

Publication number: CN115612300A
Application number: CN202211368303.XA
Authority: CN
Inventors: 曾域; 韩冰; 夏洋洋; 李兆强
Original assignee: Suzhou Taijinuo New Material Technology Co ltd
Current assignee: Suzhou Taijinuo New Material Technology Co ltd
Priority date: 2022-11-03
Filing date: 2022-11-03
Publication date: 2023-01-17
Also published as: CN117511222A

Abstract

The application relates to the technical field of heat conduction materials, in particular to a heat conduction gasket and a preparation method thereof. The application relates to a heat conduction gasket which comprises the following components in percentage by mass: 2 to 6 percent of resin A; 2 to 6 percent of resin B; 0.72 to 1.45 percent of modifier; 90-95% of heat-conducting powder; the component of the resin A and the component of the resin B both comprise addition type organic silicon resin; the resin A comprises a catalyst, and the mass ratio of the catalyst to the resin A is (2-5): 100, respectively; the resin B comprises a cross-linking agent, and the mass ratio of the cross-linking agent to the resin B is (4-8): 100, respectively; the modifier is fluoroalkyl trimethoxy silane or fluoroalkyl triethoxy silane. In addition, the application relates to three preparation methods of the heat conducting gasket. The application has the advantages of high resilience and low compression stress simultaneously.

Description

Heat conduction gasket and preparation method thereof

Technical Field

The application relates to the technical field of heat conduction materials, in particular to a heat conduction gasket and a preparation method thereof.

Background

With the rapid development of electronic technology, electronic components are rapidly developed in the directions of high performance, densification, high precision and high power, and the heat productivity of the electronic components is greatly improved, wherein the electronic components with high heat productivity are commonly referred to as heating components. In order to ensure that the heating element can stably work, a heat dissipation device is usually added on the heating element to help the heating element dissipate heat, so whether heat can be quickly led out from the heating element determines the working performance and reliability of the heating element.

The heat conducting gasket is a high-performance gap filling heat conducting material widely used in thermal interface materials, and has a good heat conducting function and high resilience rate. Between the heat dissipation device and the heating element interface, the high rebound rate of the heat conduction gasket can enable the heat conduction gasket to be in good and close contact with the heating element and the heat dissipation device all the time, the condition of falling or false contact caused by factors such as vibration and aging is avoided, the existence of low-heat-conductivity air between the heating element and the heat dissipation device interface is eliminated, and more heat conduction paths are formed, so that the effect of transferring heat from the heating element to the heat dissipation device is improved.

In practical application, in order to ensure that the heat dissipation device and the heating element are in good and sufficient contact with the heat conduction gasket, proper pressure needs to be kept between the heat dissipation device and the heating element to jointly extrude the heat conduction gasket, so that the heat conduction gasket generates internal stress due to compression. Generally, the internal stress generated by the heat conductive pad due to compression cannot exceed the safe range of the heat generating element to prevent the semiconductor device from being damaged, so the heat conductive pad needs to have lower compressive stress.

However, the rebound rate and the compressive stress of the conventional thermal conductive gasket are mutually restricted, and the conventional thermal conductive gasket on the market generally has a high rebound rate and a high compressive stress, or has a poor rebound resilience when the compressive stress is low, and cannot play a good filling role between the heating element and the heat dissipation device.

In view of the above, it is necessary to develop a thermal gasket having both high resilience and low compressive stress.

Disclosure of Invention

In order to enable the gasket to have high resilience and low compression stress at the same time, the application provides a heat-conducting gasket and a preparation method thereof.

In a first aspect, the present application provides a thermal pad, which adopts the following technical solution:

a heat-conducting gasket comprises the following components in percentage by mass:

2 to 6 percent of resin A;

2 to 6 percent of resin B;

0.72 to 1.45 percent of modifier;

90-95% of heat-conducting powder;

the component of the resin A and the component of the resin B both comprise addition type organic silicon resin;

the resin A comprises a catalyst, and the mass ratio of the catalyst to the resin A is (2-5): 100, respectively;

the resin B comprises a cross-linking agent, and the mass ratio of the cross-linking agent to the resin B is (4-8): 100, respectively;

the modifier is fluoroalkyl trimethoxy silane or fluoroalkyl triethoxy silane.

By adopting the technical scheme, molecules of the fluoroalkyl trimethoxysilane and the fluoroalkyl triethoxysilane both have organophilic groups and inotropic groups, and the organophilic groups can form chemical bonds with the surface of the heat-conducting powder, so that the molecules of the fluoroalkyl trimethoxysilane and the fluoroalkyl triethoxysilane are tightly coated on the surface of the heat-conducting powder particles through the acting force of the chemical bonds; organophilic groups of molecules of the fluoroalkyl trimethoxysilane and the fluoroalkyl triethoxysilane can be intertwined or chemically reacted with the addition type silicone resin; therefore, the compatibility of the heat-conducting powder and the addition type organic silicon resin can be improved through the fluoroalkyl trimethoxy silane and the fluoroalkyl triethoxy silane.

The molecular chains of the fluoro-alkyl trimethoxy silane and the fluoro-alkyl triethoxy silane are provided with a plurality of inert fluorine atoms, and the fluorine atoms are easy to slide relative to surrounding molecules, so that the fluoro-alkyl trimethoxy silane and the fluoro-alkyl triethoxy silane can reduce the friction force between the heat-conducting powder particles after the molecules of the fluoro-alkyl trimethoxy silane and the fluoro-alkyl triethoxy silane are coated on the surfaces of the heat-conducting powder particles, the friction force is small when adjacent powder particles are subjected to relative displacement, and the compression stress of the heat-conducting gasket is reduced.

The addition type organic silicon resin has good elasticity, mechanical property and weather resistance, so that the prepared heat-conducting gasket has good rebound rate and service life.

The crosslinking agent is selected from one or more of methyltrimethoxysilane, ethyltrimethoxysilane, decyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, methyltripropoximosilane, methyltributanonoximinosilane, phenyltributonoximosilane, vinyltributonoximosilane, tetrabutoximosilane, methyltris (methoxymethoxy) silane, ethyltris (methoxymethoxy) silane, vinyltris (methoxymethoxy) silane, phenyltris (methoxymethoxy) silane, methyltris (ethoxymethoxy) silane, tetrakis (methoxymethoxy) silane, methyltris (N, N-diethylaminooxy) silane, methyltris (N-methylacetamide) silane, methyltris (N-butylacetamide) silane, methyltris (N-cyclohexylacetamide) silane, methyltris triisopropenoxysilane, vinyltriisopropenoxysilane, phenyltriisopropenoxysilane, vinyltriacetoxysilane, methyltriethoxysilane, and phenyltriacetoxysilane.

Further preferably, the crosslinking agent is selected from methyltrimethoxysilane.

Preferably, the addition silicone resin is selected from polydimethylsiloxanes.

Preferably, the catalyst is selected from triethylenetetramine.

In a specific possible embodiment, the modifier is selected from one or more of tridecafluorooctyltriethoxysilane, heptadecafluorodecyltriethoxysilane, nonafluorohexyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, and nonafluorohexyltrimethoxysilane; preferably, the modifier is selected from one or more of heptadecafluorodecyltrimethoxysilane and heptadecafluorodecyltriethoxysilane.

In a specific implementation scheme, the heat-conducting powder comprises non-spherical heat-conducting powder and spherical heat-conducting powder, and the mass ratio of the non-spherical heat-conducting powder to the spherical heat-conducting powder is (0-1): 5.

by adopting the technical scheme, the non-spherical heat-conducting powder has good heat-conducting effect; when the heat-conducting powder is spherical, and when adjacent powder particles generate relative displacement, the spherical heat-conducting powder can reduce the friction force between the adjacent powder particles, and is favorable for reducing the compression stress of the heat-conducting gasket.

In an organic silicon resin system, the heat conducting capability and the rebound rate of the prepared heat conducting gasket can be balanced by compounding the non-spherical heat conducting powder and the spherical heat conducting powder.

In a specific possible embodiment, the heat-conducting powder comprises small-particle-size heat-conducting powder and large-particle-size heat-conducting powder, the particle size of the small-particle-size heat-conducting powder is 0.5-120 μm, and the particle size of the large-particle-size heat-conducting powder is 140-180 μm.

By adopting the technical scheme, more spaces are formed between adjacent large-particle-size powder particles to accommodate the organic silicon resin, so that the compression stress of the heat conduction gasket can be reduced while the rebound rate of the heat conduction gasket is not reduced.

Interface contact among the large-particle-size heat-conducting powder particles is less, and interface thermal resistance is lower, so that the heat-conducting capability of the heat-conducting gasket can be improved by adding the large-particle-size heat-conducting powder into an organic silicon resin system.

The small-particle-size heat-conducting powder can enable more heat-conducting powder to be filled into an organic silicon resin system with the same volume, so that the maximum stacking degree is formed among the heat-conducting powder, and the improvement of the heat-conducting capability of the heat-conducting gasket is facilitated.

In the organic silicon resin system, through the compounding of small-particle-size heat-conducting powder and large-particle-size heat-conducting powder, a plurality of small-particle-size heat-conducting powder particles are distributed around the large-particle-size heat-conducting powder particles, so that the small-particle-size heat-conducting powder particles and the large-particle-size heat-conducting powder particles are easily contacted with each other and form a heat-conducting channel, and meanwhile, when the heat-conducting gasket deforms, the small-particle-size heat-conducting powder particles are easily and flexibly displaced in the organic silicon resin system, and the compression stress of the heat-conducting gasket can be reduced while the heat-conducting performance of the heat-conducting gasket is kept not to be reduced.

In a specific embodiment, the mass ratio of the large-particle size heat-conducting powder to the small-particle size heat-conducting powder is 1: (5-15).

In a specific possible embodiment, the heat conducting powder is selected from one or more of alpha-alumina, zirconia, magnesia, zinc oxide, silicon nitride and silicon carbide; preferably, the thermally conductive powder is selected from alpha-alumina.

In a second aspect, the present application provides a method for manufacturing a thermal conductive gasket, which adopts the following technical scheme:

a preparation method of a heat-conducting gasket comprises the following steps:

(1) Mixing the resin A, the resin B and the modifier in a vacuum at 15-28 ℃ for 15-20 min according to the proportion to obtain a primary colloid;

(2) Adding heat-conducting powder into the primary colloid obtained in the step (1) at 15-28 ℃, and mixing under vacuum for 20-30 min to obtain a first colloid;

(3) And (3) rolling the first colloid obtained in the step (2) into a sheet to obtain the heat-conducting gasket.

In a third aspect, the present application provides a method for manufacturing a thermal conductive gasket, which adopts the following technical scheme:

a preparation method of a heat conduction gasket comprises the following steps:

s1, spraying a modifier on heat-conducting powder at a temperature of 15-28 ℃ according to a ratio, and uniformly mixing for 15-20 min to obtain dry modified powder;

s2, mixing the resin A, the resin B and the dry modified powder obtained in the step S1 at 15-28 ℃ for 35-45 min under vacuum to obtain a second colloid;

and S3, rolling the second colloid obtained in the step S2 into a sheet, and obtaining the heat conduction gasket.

By adopting the technical scheme, the heat-conducting powder is modified and then mixed into the organic silicon resin system, so that the coating rate of the modifier on the surfaces of the heat-conducting powder particles can be improved, the friction force between the adjacent heat-conducting powder particles is favorably reduced when the adjacent powder particles generate relative displacement, and the compression stress of the heat-conducting gasket is further reduced.

In a fourth aspect, the present application provides a method for manufacturing a thermal conductive gasket, which adopts the following technical scheme:

step 1, dissolving a modifier into an anhydrous solvent at 15-28 ℃ according to a ratio to obtain an M solution; uniformly mixing the heat-conducting powder with the M solution to obtain a mixture; drying the mixture to obtain wet modified powder;

step 2, mixing the resin A, the resin B and the wet modified powder obtained in the step 1 under vacuum at 15-28 ℃, wherein the mixing time is 35-45 min, and obtaining a second colloid;

and 3, rolling the second colloid obtained in the step 2 into a sheet to obtain the heat-conducting gasket.

By adopting the technical scheme, the modifier is dissolved in the solvent and then mixed with the heat-conducting powder, so that the uniformity of the modifier coated on the surfaces of the heat-conducting powder particles can be improved, the friction force between the adjacent heat-conducting powder particles is favorably reduced when the adjacent powder particles generate relative displacement, and the compression stress of the heat-conducting gasket is further reduced.

In summary, the present application has the following beneficial effects:

1. the modifier is coated on the surface of the heat-conducting powder particles, so that the friction force generated when adjacent powder particles are subjected to relative displacement can be reduced, and the compression stress of the heat-conducting gasket is reduced.

2. By compounding the small-particle-size heat-conducting powder and the large-particle-size heat-conducting powder, the compressive stress of the heat-conducting gasket can be reduced while the heat-conducting performance of the heat-conducting gasket is kept not to be reduced.

3. The modifier is coated on the surface of the heat-conducting powder particles, so that the compatibility of the heat-conducting powder and the addition type organic silicon resin can be improved.

Detailed Description

The present application will be described in further detail with reference to examples.

Raw materials

Some of the starting materials used in the preparation examples and examples:

dimethicone CAS number: 9016-00-6, model number: JN-201; alpha-alumina CAS number: 1344-28-1; heptadecafluorodecyltrimethoxysilane CAS number: 83048-65-1; heptadecafluorodecyltriethoxysilane CAS number: 101947-16-4; methyltrimethoxysilane CAS number: 1185-55-3; triethylene tetramine CAS number: 112-24-3; 1-ethynylcyclohexanol CAS number: 78-27-3; methyltrimethoxysilane is used as a cross-linking agent, triethylenetetramine is used as a catalyst, and 1-ethynyl cyclohexanol is used as an inhibitor.

The relevant raw materials used in the examples and comparative examples, which are not noted, are conventional products commercially available.

Resin preparation example A

Preparation example 1

A resin is prepared from the following raw materials:

196g of polydimethylsiloxane and 4g of triethylenetetramine.

A resin is prepared by the following steps:

and (3) stirring polydimethylsiloxane and triethylenetetramine at-0.09 MPa for 20min at the stirring speed of 60rpm at the temperature of 25 ℃ to obtain the resin A.

Preparation example 2

A resin A is prepared from the following raw materials:

193g of polydimethylsiloxane and 7g of triethylenetetramine.

A resin is prepared by the following steps:

Preparation example 3

A resin A is prepared from the following raw materials:

190g of polydimethylsiloxane and 10g of triethylenetetramine.

A resin is prepared by the following steps:

and (3) stirring the polydimethylsiloxane and the triethylenetetramine at the temperature of 25 ℃ below zero under the pressure of-0.09 MPa for 20min at the stirring speed of 60rpm to obtain the resin A.

Preparation of resin B

Preparation example 4

The B resin is prepared from the following raw materials:

192g of polydimethylsiloxane and 8g of methyltrimethoxysilane.

A B resin is prepared by the following steps:

and (3) stirring the polydimethylsiloxane and the methyltrimethoxysilane at the temperature of 25 ℃ below zero and the pressure of-0.09 MPa for 20min at the stirring speed of 60rpm to obtain the resin B.

Preparation example 5

The B resin is prepared from the following raw materials:

188g of polydimethylsiloxane and 12g of methyltrimethoxysilane.

A B resin is prepared by the following steps:

Preparation example 6

The B resin is prepared from the following raw materials:

184g of polydimethylsiloxane and 16g of methyltrimethoxysilane.

A B resin is prepared by the following steps:

and (3) stirring the polydimethylsiloxane and the methyltrimethoxysilane at the temperature of 25 ℃ under the pressure of-0.09 MPa for 20min at the stirring speed of 60rpm to obtain the resin B.

Examples

Example 1

A thermal gasket comprising the following components: 20g of the resin A obtained in the preparation example 1, 60g of the resin B obtained in the preparation example 4, 912.8g of heat-conducting powder and 7.2g of modifier, wherein the modifier is heptadecafluorodecyl trimethoxy silane, and the heat-conducting powder is 0.5 mu m spherical alpha-alumina.

A preparation method of a heat-conducting gasket comprises the following steps:

(1) According to the proportion, the resin A, the resin B and the heptadecafluorodecyltrimethoxysilane are stirred under the pressure of-0.09 MPa at the temperature of 25 ℃, the stirring time is 15min, and the stirring speed is 50rpm, so as to obtain a primary colloid;

(2) Adding the heat-conducting powder into the primary colloid for 3 times in equal amount at 25 ℃, and stirring at-0.09 MPa for 20min at the stirring speed of 35rpm to obtain a first colloid;

(3) And (3) rolling the first colloid obtained in the step (2) into a sheet with the thickness of 2mm to obtain the heat-conducting gasket.

Examples 2 to 5

Examples 2 to 5 are the same as example 1 except for the origin and content of the resin a, the origin and content of the resin B, the component and content of the modifier, and the particle diameter and content of the heat conductive powder, and are specifically shown in table 1:

table 1 some of the components and their contents in examples 2 to 5

Example 6

A thermal gasket comprising the following components: 30g of the resin A obtained in preparation example 1, 30g of the resin B obtained in preparation example 4, 930g of heat-conducting powder, 9.5g of modifier and 0.5g of inhibitor, wherein the modifier is heptadecafluorodecyltrimethoxysilane, the inhibitor is 1-ethynylcyclohexanol, and the heat-conducting powder is 40-micron spherical alpha-alumina.

A preparation method of a heat-conducting gasket comprises the following steps:

(1) According to the proportion, at the temperature of 25 ℃, stirring the resin A, the resin B, the 1-ethynylcyclohexanol and the heptadecafluorodecyltrimethoxysilane at the pressure of-0.09 MPa for 20min at the stirring speed of 50rpm to obtain a primary colloid;

(2) Adding the heat-conducting powder into the primary colloid for 3 times in equal amount at 25 ℃, and stirring at-0.09 MPa for 30min at the stirring speed of 35rpm to obtain a first colloid;

(3) And (3) rolling the first colloid obtained in the step (2) into a 2mm sheet to obtain the heat-conducting gasket.

Example 7

A thermally conductive gasket comprising the following components: 30g of the A resin obtained in preparation example 1, 30g of the B resin obtained in preparation example 4, 930g of heat-conducting powder, 8.5g of modifier and 0.5g of inhibitor, wherein 8.5g of heptadecafluorodecyltrimethoxysilane is selected as the modifier, 0.5g of 1-ethynylcyclohexanol is selected as the inhibitor, 810g of spherical alpha-alumina with the particle size of 40 mu m and 120g of spherical alpha-alumina with the particle size of 150 mu m are selected as the heat-conducting powder.

A preparation method of a heat conduction gasket comprises the following steps:

(2) Adding 40 mu m spherical alpha-alumina into the primary colloid obtained in the step (1) in a weight ratio for 3 times at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 35rpm to obtain primary mixed colloid;

(3) Adding 150 mu m spherical alpha-alumina into the primary colloid primary mixed glue obtained in the step (2) at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 20rpm to obtain a first colloid;

(4) And (4) rolling the first colloid obtained in the step (3) into a sheet with the thickness of 2mm to obtain the heat-conducting gasket.

Examples 8 to 9

Examples 8 to 9 are the same as example 7, except that the modifier content, i.e. heptadecafluorodecyltrimethoxysilane, was varied, as specified in Table 2:

TABLE 2 amount of heptadecafluorodecyltrimethoxysilane used in examples 8-9

Examples	Heptadecafluorodecyltrimethoxysilane/g
		Example 7	8.5
Example 8	9.5
		Example 9	10.5

Examples 10 to 11

Examples 10 to 11 are the same as example 8 except that the content of 40 μm spherical α -alumina and 150 μm spherical α -alumina is different, as shown in table 3:

TABLE 3 contents of spherical alpha-alumina having different particle diameters in examples 9 to 10

Examples 12 to 13

Examples 12 to 13 are the same as example 8 except that the contents of 40 μm spherical α -alumina and 150 μm spherical α -alumina are different, as shown in Table 4:

TABLE 4 contents of spherical alpha-alumina having different particle diameters in examples 12 to 13

Example 14

Example 14 is the same as example 8 except that:

the heat conducting powder is 810g of 0.5 mu m spherical alpha-alumina and 120g of 150 mu m spherical alpha-alumina;

step (2): and (2) adding 0.5 mu m spherical alpha-alumina into the primary colloid obtained in the step (1) for 3 times at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 35rpm to obtain the primary mixed colloid.

Example 15

Example 15 is the same as example 8, except that:

the heat conducting powder adopts 810g of 120 mu m spherical alpha-alumina and 120g of 150 mu m spherical alpha-alumina;

step (2): and (2) adding the 120 mu m spherical alpha-alumina into the primary colloid obtained in the step (1) for 3 times in parts at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 35rpm to obtain the primary mixed colloid.

Example 16

Example 16 is the same as example 8, except that:

the heat conducting powder is selected from 40 mu m spherical alpha-alumina 810g and 140 mu m spherical alpha-alumina 120g;

and (3): and (3) adding 140 mu m spherical alpha-alumina into the primary colloid primary mixed glue obtained in the step (2) at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 20rpm to obtain a first colloid.

Example 17

Example 17 is the same as example 8 except that:

the heat conducting powder is 810g of 40 mu m spherical alpha-alumina and 120g of 180 mu m spherical alpha-alumina;

and (3): and (3) adding 180-micron spherical alpha-alumina into the primary colloid primary mixed glue obtained in the step (2) at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 20rpm to obtain a first colloid.

Example 18

A thermally conductive gasket comprising the following components: 30g of the A resin obtained in preparation example 1, 30g of the B resin obtained in preparation example 4, 930g of heat conductive powder, 9.5g of a modifier and 0.5g of an inhibitor, wherein the modifier is heptadecafluorodecyltrimethoxysilane, the inhibitor is 1-ethynylcyclohexanol, the heat conductive powder is 40 μm non-spherical alpha-alumina 169.1g, 40 μm spherical alpha-alumina 640.9g and 150 μm spherical alpha-alumina 120g.

A preparation method of a heat conduction gasket comprises the following steps:

(1) Stirring the resin A, the resin B, the 1-ethynylcyclohexanol and the heptadecafluorodecyltrimethoxysilane at the temperature of 25 ℃ below zero under the pressure of-0.09 MPa for 20min at the stirring speed of 50rpm according to the mixture ratio to obtain a primary colloid;

(2) Adding 40 mu m of non-spherical alpha-alumina, 40 mu m of spherical alpha-alumina and the like into the primary colloid obtained in the step (1) for 3 times at 25 ℃, and stirring at-0.09 MPa for 15min at the stirring speed of 35rpm to obtain primary mixed colloid;

(4) And (4) rolling the first colloid obtained in the step (3) into a 2mm sheet to obtain the heat-conducting gasket.

Example 19

Example 19 is the same as example 18 except that:

155g of 40 mu m non-spherical alpha-alumina, 655g of 40 mu m spherical alpha-alumina and 120g of 150 mu m spherical alpha-alumina are selected as the heat-conducting powder.

Example 20

A thermally conductive gasket comprising the following components: 30g of the A resin obtained in preparation example 1, 30g of the B resin obtained in preparation example 4, 930g of heat conductive powder, 9.5g of a modifier and 0.5g of an inhibitor, wherein the modifier is heptadecafluorodecyltrimethoxysilane, the inhibitor is 1-ethynylcyclohexanol, and the heat conductive powder is 40 μm spherical alpha-alumina 1620g and 150 μm spherical alpha-alumina 240g.

A preparation method of a heat-conducting gasket comprises the following steps:

s1, uniformly mixing 40 mu m spherical alpha-alumina and 150 mu m spherical alpha-alumina at 25 ℃ according to a ratio to obtain primary powder; spraying heptadecafluorodecyltrimethoxysilane on the primary powder, and stirring the primary powder sprayed with heptadecafluorodecyltrimethoxysilane at-0.09 MPa for 15min at the stirring speed of 35rpm to obtain dry modified powder;

s2, stirring the resin A, the resin B, the 1-ethynylcyclohexanol and the dry modified powder obtained in the step S1 at 25 ℃ under vacuum for 40min at the stirring speed of 20rpm to obtain a second colloid;

and S3, calendering the second colloid obtained in the step S2 into a sheet, and thus obtaining the heat-conducting gasket.

Example 21

A thermal gasket comprising the following components: 30g of the resin A obtained in preparation example 1, 30g of the resin B obtained in preparation example 4, 930g of heat-conducting powder, 9.5g of a modifier and 0.5g of an inhibitor, wherein the modifier is heptadecafluorodecyltrimethoxysilane, the inhibitor is 1-ethynylcyclohexanol, and the heat-conducting powder is 40 mu m spherical alpha-alumina 810g and 150 mu m spherical alpha-alumina 120g.

A preparation method of a heat-conducting gasket comprises the following steps:

step 1, dissolving 9.5g of heptadecafluorodecyltrimethoxysilane in 85.5g of absolute ethyl alcohol at 25 ℃ according to a ratio to obtain a solution A; mixing 40 mu m spherical alpha-alumina and 150 mu m spherical alpha-alumina with the solution A and uniformly stirring to obtain a mixture; drying the mixture to obtain wet modified powder;

step 2, stirring the resin A, the resin B, the 1-ethynylcyclohexanol and the wet modified powder obtained in the step 1 at the temperature of 15-28 ℃ under the pressure of-0.09 MPa for 40min to obtain a second colloid;

Comparative example

Comparative example 1

A thermal gasket comprising the following components: 20g of the resin A obtained in the preparation example 1, 60g of the resin B obtained in the preparation example 4 and 912.8g of heat-conducting powder, wherein the heat-conducting powder is 0.5 mu m spherical alpha-alumina.

A preparation method of a heat conduction gasket comprises the following steps:

(1) Stirring the resin A and the resin B at the temperature of 25 ℃ below zero and the pressure of-0.09 MPa for 20min at the stirring speed of 50rpm according to the proportion to obtain a primary colloid;

(2) Adding the heat-conducting powder into the primary colloid for 3 times in equal amount at 25 ℃, and stirring at-0.09 MPa for 25min at the stirring speed of 35rpm to obtain a first colloid;

Detection method

The performance test of the heat conductive gaskets prepared in examples 1 to 20 and comparative example 1 was carried out by the following method:

a. and (3) testing the heat conductivity coefficient: tested according to the ASTM D5470 standard;

b. and (3) testing hardness: testing according to ASTM D2240 standard;

c. and (3) testing the rebound rate: testing according to ASTM D575-91;

d.50% compression set instantaneous compression stress: testing according to ASTM D575 standard;

e.residual compressive stress after 10min at 50% compression set: test according to ASTM D575 standard.

The properties of the thermal conductive gaskets obtained in examples 1 to 20 and comparative example 1 are shown in table 5:

TABLE 5 Properties of Heat-conducting gaskets obtained in examples 1 to 20 and comparative example 1

As can be seen from table 5, the thermal conductive gasket prepared in example 1 has a better rebound resilience, an instantaneous compressive stress at 50% compression set, and a residual compressive stress after 10min at 50% compression set than those of comparative example 1, which indicates that the thermal conductive gasket prepared in example 1 has both a high rebound ability and a low compressive stress.

It can be seen from comparison examples 7 to 9 that, as the content of heptadecafluorodecyltrimethoxysilane in the component of the heat conductive gasket increases, the instantaneous compressive stress at 50% compressive deformation and the residual compressive stress after 10min at 50% compressive deformation of the prepared heat conductive gasket both significantly decrease, indicating that increasing the content of the modifier in the component of the heat conductive gasket is beneficial to decreasing the compressive stress of the prepared heat conductive gasket. The reason for this is probably that the molecular chain of the modifier is provided with a plurality of inert fluorine atoms, so that the heat-conducting powder particles are easy to slide relative to surrounding molecules, the friction force among the heat-conducting powder particles can be reduced, the friction force when adjacent heat-conducting powder particles are subjected to relative displacement is small, and the compression stress of the heat-conducting gasket is further reduced.

As can be seen from comparison between examples 8 and 12 to 13, the rebound resilience of the prepared thermal conductive gasket is significantly improved with the increase in the content of the large-particle-size thermal conductive powder in the thermal conductive powder, which indicates that the increase in the content of the large-particle-size thermal conductive powder in the thermal conductive powder is advantageous for improving the rebound resilience of the prepared thermal conductive gasket. This is probably because there are more spaces between adjacent large-particle-size powder particles to accommodate the silicone resin, so that the content of the large-particle-size heat-conductive powder in the heat-conductive powder can be increased, which is favorable for increasing the rebound rate of the produced heat-conductive gasket.

It can be known from comparison between embodiment 6 and embodiment 8 that, in embodiment 8, through the compounding of the small-particle-size heat conductive powder and the large-particle-size heat conductive powder, the instantaneous compressive stress under 50% of compression deformation and the residual compressive stress after 10min under 50% of compression deformation of the prepared heat conductive gasket are both superior to those in embodiment 6, and the heat conductivity of the heat conductive gasket prepared in embodiment 8 is not significantly reduced, which indicates that through the compounding of the small-particle-size heat conductive powder and the large-particle-size heat conductive powder, the rebound rate of the prepared heat conductive gasket is favorably improved on the premise of not reducing the heat conductivity of the heat conductive gasket. The small-particle-size heat-conducting powder and the large-particle-size heat-conducting powder are compounded, and a plurality of small-particle-size heat-conducting powder particles are distributed around the large-particle-size heat-conducting powder particles, so that the small-particle-size heat-conducting powder particles and the large-particle-size heat-conducting powder particles are easily contacted with each other and form a heat-conducting channel, and meanwhile, when the heat-conducting gasket is deformed, the small-particle-size heat-conducting powder particles are easily and flexibly displaced in an organic silicon resin system, and the compression stress of the heat-conducting gasket is reduced while the heat-conducting performance of the heat-conducting gasket is kept not to be reduced.

The specific embodiments are only for explaining the present application and are not limiting to the present application, and those skilled in the art can make modifications to the embodiments without inventive contribution as required after reading the present specification, but all the embodiments are protected by patent law within the scope of the claims of the present application.

Claims

1. A thermally conductive gasket, comprising: the paint comprises the following components in percentage by mass:

2 to 6 percent of resin A;

2 to 6 percent of resin B;

0.72 to 1.45 percent of modifier;

90 to 95 percent of heat-conducting powder;

the modifier is fluoroalkyl trimethoxy silane or fluoroalkyl triethoxy silane.

2. A thermal gasket according to claim 1, wherein: the modifier is selected from one or more of tridecafluorooctyltriethoxysilane, heptadecafluorodecyltriethoxysilane, nonafluorohexyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane and nonafluorohexyltrimethoxysilane.

3. A thermal gasket according to claim 1, wherein: the heat conducting powder comprises non-spherical heat conducting powder and spherical heat conducting powder, and the mass ratio of the non-spherical heat conducting powder to the spherical heat conducting powder is (0-1): 5.

4. a thermal gasket according to claim 1, wherein: the heat-conducting powder comprises small-particle-size heat-conducting powder and large-particle-size heat-conducting powder, wherein the particle size of the small-particle-size heat-conducting powder is 0.5-120 mu m, and the particle size of the large-particle-size heat-conducting powder is 140-180 mu m.

5. A thermal gasket according to claim 4, wherein: the mass ratio of the large-particle-size heat-conducting powder to the small-particle-size heat-conducting powder is 1: (5-15).

6. A thermal gasket according to claim 1, wherein: the heat conducting powder is selected from one or more of alpha-alumina, zirconia, magnesia, zinc oxide, silicon nitride and silicon carbide.

7. The method for manufacturing a thermal gasket according to any one of claims 1 to 6, comprising the steps of:

8. The method for preparing a thermal gasket according to any one of claims 1 to 6, comprising the steps of:

9. The method for manufacturing a thermal gasket according to any one of claims 1 to 6, comprising the steps of: