CN103333494B - A kind of Thermal-conductive insulation silicone rubber thermal interface material and preparation method thereof - Google Patents

Abstract

The invention discloses a heat-conducting and insulating silicone rubber thermal interface material and a preparation method thereof, which comprises the following steps: 1) surface treatment of heat-conducting fillers; 2) heat-conducting fillers of different particle sizes are blended with a silicone rubber matrix in sequence according to particle sizes ;3) High-temperature molding or calendering vulcanization; 4) Secondary vulcanization to obtain a controllable thickness of 0.2-5mm, a controllable Shore A hardness of 10-60 degrees, and a controllable thermal conductivity of 0.8-2.5W/(m·K). The crack strength is greater than 3kN/mm sheet thermal insulation silicone thermal interface material; 5) Paste the release film. The sheet-shaped heat-conducting insulating silicone rubber thermal interface material has the characteristics of high thermal conductivity, good insulation performance, high tear strength, stable performance, and convenient use. It is suitable for heat dissipation pads of high-power LEDs, tablet computers, mobile phones, power supplies and other electronic devices. piece.

Description

A thermally conductive insulating silicone rubber thermal interface material and preparation method thereof

technical field

The invention belongs to the field of thermal interface materials, and relates to a heat-conducting insulating silicone rubber thermal interface material with high thermal conductivity, good insulation performance, high tear strength and good stability and a preparation method thereof.

Background technique

In recent years, with the rapid development of the semiconductor device integration process, the direction of miniaturization, light weight and high efficiency has made heat dissipation an increasingly important issue, and its requirements for heat dissipation are also getting higher and higher. Since the contact interface between the heat sink and the semiconductor integrated device is not smooth, generally less than 20% of the area is in contact with each other, which greatly affects the heat transfer effect from the semiconductor device to the heat sink. It is necessary to add a layer of thermal interface material between the contact interfaces to increase the heat conduction between the interfaces.

The purpose of a thermal interface material is to reduce the thermal resistance between the device and the heat sink. After adding the thermal interface material, the thermal resistance can generally be divided into two parts, one part is the thermal resistance of the thermal interface material itself, this part of the thermal resistance is proportional to the thickness of the thermal interface material, and inversely proportional to the thermal conductivity of the thermal interface material, so the thermal interface material is required High thermal conductivity, thin thickness. Another part of the thermal resistance is the thermal contact resistance between the thermal interface material and the heat-generating device, and between the thermal interface material and the heat sink. There are many factors affecting this part of the thermal resistance, including the filling rate of the thermal interface material on the rough surface of the heating device and the heat sink, the contact pressure, and the thermal conductivity of the thermal interface material, etc., which require the thermal interface material to have good flexibility and gap filling Good performance, low hardness and high thermal conductivity. In addition, from the perspective of the use of thermal interface materials, thermal interface materials are generally required to have good thermal cycle stability, aging resistance, simple construction, detachable, and low cost.

Silicone rubber has the advantages of good insulation performance, high resilience, and good flexibility, but the thermal conductivity of unfilled silicone rubber is very poor, and the thermal conductivity is generally only about 0.2W/(m K). Generally, it needs to be filled with thermally conductive fillers. Thermal conductivity, so as to meet the requirements of thermal interface materials. The thermal conductivity of silicone rubber composites filled with thermally conductive fillers mainly depends on the thermal conduction between the fillers. A single micron-sized filler filled with silicone rubber has fewer interfaces and less phonon scattering, so the contact thermal resistance between the fillers is small, but the particle size of the micron-sized filler is large, the gaps formed between the fillers are also large, and there are few contacts between the fillers. It is impossible to form a tighter packing, which limits the improvement of thermal conductivity. Silicone rubber is filled with a single nanoscale filler, the interaction force between the filler and the silicone rubber matrix is large, the contact thermal resistance is small, and the nanofiller is easier to fill the surface of the rough device well, thereby obtaining low thermal resistance. However, the problem of nano-scale fillers is that the proportion of the interface between the fillers is large, and the phonon scattering is serious, which will limit the improvement of the thermal conductivity of the composite material. In addition, the thermal conductivity of filled polymer composites depends largely on the filling amount of thermally conductive fillers. The larger the filling amount, the denser the thermal conduction network formed between the thermally conductive fillers, and the higher the thermal conductivity. However, with ordinary sheet-shaped fillers, as the filling amount increases, the viscosity of the composite material increases sharply. When the filler is filled to a certain volume fraction, the composite material becomes difficult to process, so that high filling cannot be obtained, which also affects the thermal conductivity. improvement.

Contents of the invention

In view of the above-mentioned deficiencies, the object of the present invention is to provide a heat-conducting and insulating silicone rubber thermal interface material with high thermal conductivity, good insulation performance, good stability and convenient use and a preparation method thereof. It is a thermally conductive and insulating silicone rubber thermal interface material with multi-scale composite filling and a preparation method. It is suitable for the interface heat transfer between the heating element and the heat dissipation element, and is used to dissipate the heat generated by the heating element or similar purposes.

To achieve the above object, the technical solution provided by the present invention is:

A thermally conductive and insulating silicone rubber thermal interface material, characterized in that it is made of the following components in mass percentage:

The micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is compounded with various particle sizes, and the compounded particle size ranges from 2 μm to 100 μm.

The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the nano-alumina particle size ranges from 10 to 100 nm; the boron nitride is hexagonal boron nitride, and the particle size range is 1 ~40 μm; the aspect ratio of the zinc oxide whiskers is greater than 5:1.

The surface treatment agent is one or more of KH550, KH560, KH570, A151 and Si-69.

The softener is one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

A method for preparing the heat-conducting insulating silicone rubber thermal interface material described in the right, characterized in that: in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main heat-conducting filler to reduce the viscosity of the filling system and improve The filling amount of thermally conductive fillers; the softener is used to reduce the hardness of thermally conductive insulating silicone rubber after molding; the thermal conductivity is further improved and the thermal resistance is reduced by compounding nano-alumina, boron nitride, and zinc oxide whiskers treated with surface treatment agents.

Its specific preparation process comprises the following steps:

1) Surface treatment of multi-scale composite thermally conductive fillers: prepare surface treatment agents into corresponding solutions, and then perform surface treatment on various thermally conductive fillers of different scales respectively. After the treatment is completed, filter, dry, and pulverize to obtain various surface treatments. Good thermally conductive filler; the various thermally conductive fillers of different scales include micron alumina, nano-alumina, boron nitride and zinc oxide whiskers; wherein, the micron-alumina is the main thermally conductive filler, and the nano-alumina, Boron nitride and zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) Add the surface-treated thermally conductive filler obtained in step 1) into the silicone rubber matrix in order of particle size from large to small, and add a softener, knead and knead in a vacuum kneader under vacuum, and take out After standing at room temperature for 24 hours, a multi-scale compound filled thermally conductive silicone rubber compound was obtained;

3) Pass the mixed rubber obtained in step 2) on an open mill, add a vulcanizing agent during the thin pass, and then carry out high-temperature molding vulcanization or calender vulcanization to obtain a formed sheet-shaped silica gel material;

4) High-temperature secondary vulcanization of the formed sheet-shaped silica gel material obtained in step 3) to obtain a sheet-shaped thermally conductive and insulating silicone thermal interface material from which small molecule volatiles have been removed; each component of the thermally conductive and insulating silicone thermal interface material The mass percentages are as follows:

It also includes the steps of:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

The shape of the micro-alumina is spherical, and the particle size is a compound of various particle sizes, and the compound particle size ranges from 2 μm to 100 μm; the particle size of the nano-alumina ranges from 10 to 100 nm; the boron nitride is hexagonal Boron nitride has a particle size ranging from 1 to 40 μm; the aspect ratio of the zinc oxide whiskers is greater than 5:1.

The surface treatment agent is one or more of KH550, KH560, KH570, A151, and Si-69; the softener is hydroxyl silicone oil, magnesium carbonate, methylpolysiloxane containing hydrolyzable groups, and a degree of polymerization of 200 One or more of polysiloxanes with a low degree of polymerization of ~2000.

Compared with the prior art, the present invention achieves the following beneficial effects: through compounding and filling silicone rubber with thermally conductive fillers of different shapes, particle sizes and thermal conductivity, the filling amount of the thermally conductive filler is increased, so that the volume filling amount reaches more than 60%, and the thermal conductivity It reaches 2.3W/(m K), and has good flexibility, tensile strength, tear strength and electrical insulation properties at the same time, which solves the problem of thermal conductivity, hardness, tear strength and electrical insulation in the prior art. The problem. The sheet-shaped heat-conducting and insulating silicone rubber thermal interface material of the present invention uses high-temperature vulcanized silicone rubber, and the amount of low-molecular siloxane is small. After vulcanization, the rubber has good resilience, excellent shock resistance, good aging resistance, and is easy to install. , disassembled and reusable.

Detailed ways

Example 1:

The thermally conductive insulating silicone rubber thermal interface material provided by the present invention is made of the following components in mass percentage:

Wherein, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, and the compound particle size ranges from 2 μm to 100 μm. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the nano-alumina particle size ranges from 10 to 100 nm; the boron nitride is hexagonal boron nitride, and the particle size range is 1 ~40 μm; the aspect ratio of the zinc oxide whiskers is greater than 5:1. The surface treatment agent is one or more of KH550, KH560, KH570, A151 and Si-69. The softener is one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

In the method for preparing the aforementioned heat-conducting and insulating silicone rubber thermal interface material provided by the present invention, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main heat-conducting filler to reduce the viscosity of the filling system and increase the filling amount of the heat-conducting filler , reduce the hardness of heat-conducting insulating silicone rubber after molding by softening agent; by compounding nano-alumina, boron nitride, and zinc oxide whiskers treated by compounding surface treatment agent, the thermal conductivity is further improved and the thermal resistance is reduced.

Its specific preparation process comprises the following steps:

1) Surface treatment of multi-scale composite thermally conductive fillers: prepare surface treatment agents into corresponding solutions, and then perform surface treatment on various thermally conductive fillers of different scales respectively. After the treatment is completed, filter, dry, and pulverize to obtain various surface treatments. Good thermally conductive filler; the various thermally conductive fillers of different scales include micron alumina, nano-alumina, boron nitride and zinc oxide whiskers; wherein, the micron-alumina is the main thermally conductive filler, and the nano-alumina, Boron nitride and zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) Add the surface-treated thermally conductive filler obtained in step 1) into the silicone rubber matrix in order of particle size from large to small, and add a softener, knead and knead in a vacuum kneader under vacuum, and take out After standing at room temperature for 24 hours, a multi-scale compound filled thermally conductive silicone rubber compound was obtained;

3) Pass the mixed rubber obtained in step 2) on an open mill, add a vulcanizing agent during the thin pass, and then carry out high-temperature molding vulcanization or calender vulcanization to obtain a formed sheet-shaped silica gel material;

4) High-temperature secondary vulcanization of the formed sheet-shaped silica gel material obtained in step 3) to obtain a sheet-shaped thermally conductive and insulating silicone thermal interface material from which small molecule volatiles have been removed; each component of the thermally conductive and insulating silicone thermal interface material The mass percentages are as follows:

It also includes the following steps: 5) Paste a release film on the upper and lower surfaces of the sheet-shaped heat-conducting insulating silicone thermal interface material obtained in step 4) for storage and use.

The shape of the micro-alumina is spherical, and the particle size is a compound of various particle sizes, and the compound particle size ranges from 2 μm to 100 μm; the particle size of the nano-alumina ranges from 10 to 100 nm; the boron nitride is hexagonal Boron nitride has a particle size ranging from 1 to 40 μm; the aspect ratio of the zinc oxide whiskers is greater than 5:1. The surface treatment agent is one or more of KH550, KH560, KH570, A151, and Si-69; the softener is hydroxyl silicone oil, magnesium carbonate, methylpolysiloxane containing hydrolyzable groups, and a degree of polymerization of 200 One or more of polysiloxanes with a low degree of polymerization of ~2000.

Example 2:

The heat-conducting and insulating silicone rubber thermal interface material provided in this embodiment and its preparation method are basically the same as in Example 1, the difference being that the composition and weight percentage of the heat-conducting and insulating silicone rubber thermal interface material are as follows:

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 42% of 40 μm spherical alumina and 18% of 2 μm spherical alumina. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride, and the particle size is 35 μm; the oxide The aspect ratio of zinc whiskers is 10:1. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

In the preparation method of the heat-conducting and insulating silicone rubber thermal interface material, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main heat-conducting filler, so as to reduce the viscosity of the filling system, increase the filling amount of the heat-conducting filler, and pass the softener Reduce the hardness of heat-conducting and insulating silicone rubber after molding; by compounding nano-alumina, boron nitride, and zinc oxide whiskers treated with surface treatment agents, the thermal conductivity is further improved and the thermal resistance is reduced.

The specific implementation process is as follows:

1) Surface treatment of multi-scale composite thermally conductive filler: 95 parts of absolute ethanol and 5 parts of deionized water are made into an alcoholic aqueous solution, and the pH value is adjusted to 4 with acetic acid; the coupling agent KH570 is added according to the above ratio, and electromagnetic stirring is performed for 10 Minutes later, the prepared KH570 surface treatment solution was obtained; 40μm spherical alumina, 2μm spherical alumina, 40nm alumina, 35μm boron nitride and zinc oxide whiskers with an aspect ratio of 10:1 were treated with KH570 surface treatment solution , the treatment condition is 60°C, electromagnetic stirring for 2 hours, drying and crushing after filtration to obtain various thermally conductive fillers with surface treatment; wherein, the micron alumina is the main thermally conductive filler, and the nanometer alumina, boron nitride , Zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) The surface-treated 40μm spherical alumina, 35μm boron nitride, 2μm spherical alumina, 40nm alumina and zinc oxide whiskers with a length-to-diameter ratio of 10:1 obtained in step 1) were selected according to the particle size from large to large Add it to the silicone rubber matrix in order of size, and add a hydroxy silicone oil softener, knead in vacuum for 30 minutes, take it out and place it at room temperature for 24 hours to obtain a multi-scale compound filled thermally conductive insulating silicone rubber compound;

3) Pass the mixed rubber obtained in step 2) on the twin-shaft mixer for 4 to 6 times, and add bis-2,5 vulcanizing agent with a weight percentage of 1.5% of the silicone rubber matrix during the thin pass, and thin pass After the sheet is released, perform high-temperature molding vulcanization at 170°C for 15 minutes to obtain a formed sheet-shaped silica gel material;

4) Secondary vulcanization of the formed sheet-shaped silica gel material at 200°C for 4 hours to obtain a sheet-shaped thermally conductive insulating silicone rubber thermal interface material with a thickness of 2 mm from which small molecule volatiles have been removed; the thermally conductive insulating silicone thermal interface material The mass percentages of each component are as follows:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 42% of 40 μm spherical alumina and 18% of 2 μm spherical alumina. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride, and the particle size is 35 μm; the oxide The aspect ratio of zinc whiskers is 10:1. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

Test its related performance as follows:

In this embodiment, the particle size of the micron alumina is a compound of two particle sizes, which can be replaced by three or more, and the compound particle size ranges from 2 μm to 100 μm, which is also applicable. It is also applicable to replace the surface treatment agent with one or more of KH550, KH560, KH570, A151, and Si-69. It is also suitable to replace the softener with one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

Example 3: The thermally conductive and insulating silicone rubber thermal interface material and its preparation method provided in this example are basically the same as those in Examples 1 and 2, except that the composition and weight percentage of the thermally conductive and insulating silicone rubber thermal interface material as follows:

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 50% of 70 μm spherical alumina and 15% of 5 μm spherical alumina. The nano-alumina and boron nitride are auxiliary heat-conducting fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride with a particle size of 35 μm. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

In the preparation method of the thermally conductive insulating silicone rubber thermal interface material, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main thermally conductive filler in the silicone rubber matrix, so as to reduce the viscosity of the filling system and improve the thermal conductivity of the filler. Filling amount, the softener is used to reduce the hardness of the heat-conducting insulating silicone rubber after molding; the nano-alumina and boron nitride treated by compounding the surface treatment agent further increase the thermal conductivity and reduce the thermal resistance.

The specific implementation process is as follows:

1) Surface treatment of multi-scale composite thermally conductive fillers: 95 parts of absolute ethanol and 5 parts of deionized water were made into an alcoholic aqueous solution, and the pH value was adjusted to 4 with acetic acid. Add coupling agent KH570 according to the above ratio, and after electromagnetic stirring for 10 minutes, the prepared KH570 surface treatment solution is obtained; 70 μm spherical alumina, 5 μm spherical alumina, 40nm alumina and 35 μm boron nitride are respectively treated with KH570 surface treatment solution , the treatment condition is 60°C, electromagnetic stirring for 2 hours, drying and crushing after filtration to obtain various thermally conductive fillers with surface treatment; wherein, the micron alumina is the main thermally conductive filler, and the nanometer alumina, boron nitride As auxiliary heat conduction filler;

2) Add the surface-treated 70 μm spherical alumina, 35 μm boron nitride, 5 μm spherical alumina and 40nm alumina obtained in step 1) into the silicone rubber matrix in order from large to small according to the particle size, And add a hydroxy silicone oil softener, knead in vacuum for 30 minutes, take it out and place it at room temperature for 24 hours to obtain a multi-scale compound filled thermally conductive insulating silicone rubber compound;

3) Pass the mixed rubber obtained in step 2) on the twin-shaft mixer for 4 to 6 times, and add bis-2,5 vulcanizing agent with a weight percentage of 1.5% of the silicone rubber matrix during the thin pass, and thin pass After the sheet is released, perform high-temperature molding vulcanization at 170°C for 15 minutes to obtain a formed sheet-shaped silica gel material;

4) Secondary vulcanization of the formed sheet-shaped silica gel material at 200°C for 4 hours to obtain a sheet-shaped thermally conductive insulating silicone rubber thermal interface material with a thickness of 2 mm from which small molecule volatiles have been removed; the thermally conductive insulating silicone thermal interface material The mass percentages of each component are as follows:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 50% of 70 μm spherical alumina and 15% of 5 μm spherical alumina. The nano-alumina and boron nitride are auxiliary heat-conducting fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride with a particle size of 35 μm. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

Test its related performance as follows:

In this embodiment, the particle size of the micron alumina is a compound of two particle sizes, which can be replaced by three or more, and the compound particle size ranges from 2 μm to 100 μm, which is also applicable. It is also applicable to replace the surface treatment agent with one or more of KH550, KH560, KH570, A151, and Si-69. It is also suitable to replace the softener with one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

Example 4:

The thermally conductive insulating silicone rubber thermal interface material and its preparation method provided in this example are basically the same as those in Examples 1, 2, and 3, except that the composition and weight percentage of the thermally conductive insulating silicone rubber thermal interface material are as follows :

Among them, the micron alumina is the main thermal conductive filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 35% of 100 μm spherical alumina and 15% of 2 μm spherical alumina. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 10nm; the boron nitride is hexagonal boron nitride, and the particle size is 40 μm; the oxide The aspect ratio of zinc whiskers is 20:1. Described surface treatment agent is KH550. Described softener is magnesium carbonate softener.

In the preparation method of the thermally conductive insulating silicone rubber thermal interface material, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main thermally conductive filler in the silicone rubber matrix, so as to reduce the viscosity of the filling system and improve the thermal conductivity of the filler. Filling amount, the hardness of thermally conductive insulating silicone rubber after molding is reduced by softener; the thermal conductivity is further improved and thermal resistance is reduced by compounding nano-alumina, boron nitride, and zinc oxide whiskers treated with surface treatment agents.

The specific implementation process is as follows:

1) Surface treatment of multi-scale compound thermally conductive filler: 95 parts of absolute ethanol and 5 parts of deionized water are made into an alcoholic aqueous solution, and the pH value is adjusted to 4 with acetic acid; the coupling agent KH550 is added according to the above ratio, and electromagnetic stirring is performed for 10 After 10 minutes, the prepared KH550 surface treatment solution was obtained; 100μm spherical alumina, 2μm spherical alumina, 10nm alumina, 40μm boron nitride and zinc oxide whiskers with an aspect ratio of 20:1 were treated with KH550 surface treatment solution , the treatment condition is 60°C, electromagnetic stirring for 2 hours, drying and crushing after filtration to obtain various thermally conductive fillers with surface treatment; wherein, the micron alumina is the main thermally conductive filler, and the nanometer alumina, boron nitride , Zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) The surface-treated 100μm spherical alumina, 40μm boron nitride, 2μm spherical alumina, 10nm alumina and zinc oxide whiskers with a length-to-diameter ratio of 20:1 obtained in step 1) were selected according to the particle size from large to large Add it to the silicone rubber matrix in order of size, and add magnesium carbonate softener, knead in vacuum for 30 minutes, take it out and place it at room temperature for 24 hours to obtain a multi-scale compound filled thermally conductive insulating silicone rubber compound;

3) Pass the mixed rubber obtained in step 2) on the twin-shaft mixer for 4 to 6 times, and add bis-2,5 vulcanizing agent with a weight percentage of 1.5% of the silicone rubber matrix during the thin pass, and thin pass After the sheet is released, perform high-temperature molding vulcanization at 170°C for 15 minutes to obtain a formed sheet-shaped silica gel material;

4) Secondary vulcanization of the formed sheet-shaped silica gel material at 200°C for 4 hours to obtain a sheet-shaped heat-conducting insulating silicone rubber thermal interface material with a thickness of 2mm that removes small molecule volatiles;

The mass percentages of each component of the thermally conductive and insulating silicone thermal interface material are as follows:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

Among them, the micron alumina is the main thermal conductive filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 35% of 100 μm spherical alumina and 15% of 2 μm spherical alumina. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 10nm; the boron nitride is hexagonal boron nitride, and the particle size is 40 μm; the oxide The aspect ratio of zinc whiskers is 20:1. Described surface treatment agent is KH550. Described softener is magnesium carbonate softener.

Test its related performance as follows:

In this embodiment, the particle size of the micron alumina is a compound of two particle sizes, which can be replaced by three or more, and the compound particle size ranges from 2 μm to 100 μm, which is also applicable. It is also applicable to replace the surface treatment agent with one or more of KH550, KH560, KH570, A151, and Si-69. It is also suitable to replace the softener with one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

Example 5: The thermally conductive and insulating silicone rubber thermal interface material and its preparation method provided in this example are basically the same as those in Examples 1, 2, 3, and 4, except that the thermally conductive and insulating silicone rubber thermal interface material The composition and weight percentage are as follows:

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 60 μm spherical alumina 50% and 8 μm spherical alumina 20%. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 100nm; the boron nitride is hexagonal boron nitride, and the particle size is 10 μm; the oxide The aspect ratio of zinc whiskers is 15:1. Described surface treatment agent is KH550. The softener is a methylpolysiloxane softener containing hydrolyzable groups.

In the preparation method of the heat-conducting and insulating silicone rubber thermal interface material, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main heat-conducting filler, so as to reduce the viscosity of the filling system, increase the filling amount of the heat-conducting filler, and pass the softener Reduce the hardness of heat-conducting and insulating silicone rubber after molding; by compounding nano-alumina, boron nitride, and zinc oxide whiskers treated with surface treatment agents, the thermal conductivity is further improved and the thermal resistance is reduced.

The specific implementation process is as follows:

1) Surface treatment of multi-scale compound thermally conductive filler: 95 parts of absolute ethanol and 5 parts of deionized water are made into an alcoholic aqueous solution, and the pH value is adjusted to 4 with acetic acid; the coupling agent KH550 is added according to the above ratio, and electromagnetic stirring is performed for 10 After 10 minutes, the prepared KH550 surface treatment solution was obtained; 60μm spherical alumina, 8μm spherical alumina, 100nm alumina, 10μm boron nitride and zinc oxide whiskers with an aspect ratio of 1:15 were treated with KH550 surface treatment solution , the treatment condition is 60°C, electromagnetic stirring for 2 hours, drying and crushing after filtration to obtain various thermally conductive fillers with surface treatment; wherein, the micron alumina is the main thermally conductive filler, and the nanometer alumina, boron nitride , Zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) The surface-treated 60μm spherical alumina, 10μm boron nitride, 8μm spherical alumina, 100nm alumina and zinc oxide whiskers with an aspect ratio of 1:15 obtained in step 1) were selected according to the particle size from large to large Add it to the silicone rubber matrix in order of size, and add methyl polysiloxane softener containing hydrolyzable groups, knead for 30 minutes in vacuum, take it out and place it at room temperature for 24 hours to obtain a multi-scale compound filled thermally conductive insulating silicone rubber compound rubber mixing;

3) Pass the mixed rubber obtained in step 2) on the twin-shaft mixer for 4 to 6 times, and add bis-2,5 vulcanizing agent with a weight percentage of 1.5% of the silicone rubber matrix during the thin pass, and thin pass After the sheet is released, perform high-temperature molding vulcanization at 170°C for 15 minutes to obtain a formed sheet-shaped silica gel material;

4) Secondary vulcanization of the formed sheet-shaped silica gel material at 200°C for 4 hours to obtain a sheet-shaped heat-conducting insulating silicone rubber thermal interface material with a thickness of 2mm that removes small molecule volatiles;

The mass percentages of each component of the thermally conductive and insulating silicone thermal interface material are as follows:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 60 μm spherical alumina 50% and 8 μm spherical alumina 20%. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 100nm; the boron nitride is hexagonal boron nitride, and the particle size is 10 μm; the oxide The aspect ratio of zinc whiskers is 15:1. Described surface treatment agent is KH550. The softener is a methylpolysiloxane softener containing hydrolyzable groups.

Test its related performance as follows:

In this embodiment, the particle size of the micron alumina is a compound of two particle sizes, which can be replaced by three or more, and the compound particle size ranges from 2 μm to 100 μm, which is also applicable. It is also applicable to replace the surface treatment agent with one or more of KH550, KH560, KH570, A151, and Si-69. It is also suitable to replace the softener with one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

Embodiment 6: The thermally conductive and insulating silicone rubber thermal interface material and its preparation method provided in this embodiment are basically the same as those in Examples 1 to 5, the difference lies in the composition and weight of the thermally conductive and insulating silicone rubber thermal interface material The percentages are as follows:

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 40 μm spherical alumina 25% and 2 μm spherical alumina 5%. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride, and the particle size is 35 μm; the oxide The aspect ratio of zinc whiskers is 10:1. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

In the preparation method of the heat-conducting and insulating silicone rubber thermal interface material, in the silicone rubber matrix, micron alumina treated with a surface treatment agent is used as the main heat-conducting filler through a softener, so as to reduce the viscosity of the filling system and increase the filling amount of the heat-conducting filler , and the nano-alumina, boron nitride, and zinc oxide whiskers treated by compounding surface treatment agents are used as auxiliary thermal conductivity fillers to further improve thermal conductivity and reduce thermal resistance.

The specific implementation process is as follows:

1) Surface treatment of multi-scale composite thermally conductive filler: 95 parts of absolute ethanol and 5 parts of deionized water are made into an alcoholic aqueous solution, and the pH value is adjusted to 4 with acetic acid; the coupling agent KH570 is added according to the above ratio, and electromagnetic stirring is performed for 10 Minutes later, the prepared KH570 surface treatment solution was obtained; 40μm spherical alumina, 2μm spherical alumina, 40nm alumina, 35μm boron nitride and zinc oxide whiskers with an aspect ratio of 10:1 were treated with KH570 surface treatment solution , the treatment condition is 60°C, electromagnetic stirring for 2 hours, drying and crushing after filtration to obtain various thermally conductive fillers with surface treatment; wherein, the micron alumina is the main thermally conductive filler, and the nanometer alumina, boron nitride , Zinc oxide whiskers are auxiliary thermal conductivity fillers;

2) The surface-treated 40μm spherical alumina, 35μm boron nitride, 2μm spherical alumina, 40nm alumina and zinc oxide whiskers with a length-to-diameter ratio of 10:1 obtained in step 1) were selected according to the particle size from large to large Add it to the silicone rubber matrix in order of size, and add a hydroxy silicone oil softener, knead in vacuum for 30 minutes, take it out and place it at room temperature for 24 hours to obtain a multi-scale compound filled thermally conductive insulating silicone rubber compound;

3) Pass the mixed rubber obtained in step 2) on the twin-shaft mixer for 4 to 6 times, and add bis-2,5 vulcanizing agent with a weight percentage of 1.5% of the silicone rubber matrix during the thin pass, and thin pass After the sheet is released, perform high-temperature molding vulcanization at 170°C for 15 minutes to obtain a formed sheet-shaped silica gel material;

4) Secondary vulcanization of the formed sheet-shaped silica gel material at 200°C for 4 hours to obtain a sheet-shaped thermally conductive insulating silicone rubber thermal interface material with a thickness of 2 mm from which small molecule volatiles have been removed; the thermally conductive insulating silicone thermal interface material The mass percentages of each component are as follows:

5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone thermal interface material obtained in step 4) for storage and use.

Among them, the micron alumina is the main heat-conducting filler, the shape is spherical, and the particle size is a compound of various particle sizes, which is a compound of 40 μm spherical alumina 25% and 2 μm spherical alumina 5%. The nano-alumina, boron nitride, and zinc oxide whiskers are auxiliary thermally conductive fillers; wherein, the particle size of the nano-alumina is 40nm; the boron nitride is hexagonal boron nitride, and the particle size is 35 μm; the oxide The aspect ratio of zinc whiskers is 10:1. Described surface treatment agent is KH570. The softener is a hydroxy silicone oil softener.

Test its related performance as follows:

In this embodiment, the particle size of the micron alumina is a compound of two particle sizes, which can be replaced by three or more, and the compound particle size ranges from 2 μm to 100 μm, which is also applicable. It is also applicable to replace the surface treatment agent with one or more of KH550, KH560, KH570, A151, and Si-69. It is also suitable to replace the softener with one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.

The above are only preferred feasible embodiments of the present invention, and are not intended to limit the patent scope of the present invention, so all equivalent changes made by using the content of the description of the present invention are included in the protection scope of the present invention.

Claims (6)

1. A heat-conducting and insulating silicone rubber thermal interface material, characterized in that: it is made of the following mass percentage components: The micron alumina is the main thermally conductive filler, the shape is spherical, and the particle size is a compound of various particle sizes, and the compound particle size ranges from 2 μm to 100 μm; the nano-alumina, boron nitride, and zinc oxide whiskers are Auxiliary thermally conductive filler; wherein, the nano-alumina particle size range is 10-100nm; the boron nitride is hexagonal boron nitride, and the particle size range is 1-40 μm; the zinc oxide whisker aspect ratio is greater than 5: 1. 2. The heat-conducting and insulating silicone rubber thermal interface material according to claim 1, wherein the surface treatment agent is one or more of KH550, KH560, KH570, A151, and Si-69. 3. The heat-conducting and insulating silicone rubber thermal interface material according to claim 1, characterized in that: the softener is hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and a low degree of polymerization of 200-2000. One or more of polysiloxanes with a degree of polymerization. 4. A method for preparing the thermally conductive insulating silicone rubber thermal interface material according to any one of claims 1 to 3, characterized in that: its specific preparation process comprises the following steps: 1) Surface treatment of multi-scale composite thermally conductive fillers: prepare surface treatment agents into corresponding solutions, and then perform surface treatment on various thermally conductive fillers of different scales, filter, dry, and pulverize after treatment to obtain various surface treatments Good thermally conductive filler; the various thermally conductive fillers of different scales include micron alumina, nano-alumina, boron nitride and zinc oxide whiskers; wherein, the micron-alumina is the main thermally conductive filler, and the nano-alumina, Boron nitride and zinc oxide whiskers are auxiliary thermal conductivity fillers; 2) Add the surface-treated thermally conductive filler obtained in step 1) into the silicone rubber matrix in order of particle size from large to small, and add a softener, carry out vacuum kneading and mixing in a vacuum kneader, and take out After standing at room temperature for 24 hours, a multi-scale compound filled thermally conductive silicone rubber compound was obtained; 3) Pass the mixed rubber obtained in step 2) on an open mill, add a vulcanizing agent during the thin pass, perform high-temperature molding vulcanization or calender vulcanization after thin pass, and obtain a formed sheet-shaped silica gel material; 4) High-temperature secondary vulcanization of the formed sheet-shaped silica gel material obtained in step 3) to obtain a sheet-shaped thermally conductive insulating silicone rubber thermal interface material from which small molecule volatiles have been removed; each of the thermally conductive insulating silicone rubber thermal interface materials Component mass percentages are as follows: In the silicone rubber matrix, the micron alumina treated with the surface treatment agent is used as the main thermal conductive filler to reduce the viscosity of the filling system and increase the filling amount of the thermal conductive filler; the softener is used to reduce the hardness of the thermally conductive insulating silicone rubber after molding; Nano-alumina, boron nitride, and zinc oxide whiskers treated with surface treatment agents can further improve thermal conductivity and reduce thermal resistance; the shape of the micron alumina is spherical, and the particle size is a compound of various particle sizes. The particle size range of the nano-alumina is 2 μm to 100 μm; the particle size range of the nano-alumina is 10-100 nm; the boron nitride is hexagonal boron nitride, and the particle size range is 1-40 μm; the zinc oxide whisker aspect ratio Greater than 5:1. 5. The method for preparing thermally conductive insulating silicone rubber thermal interface material as claimed in claim 4, characterized in that: it also includes the following steps: 5) Paste a layer of release film on the upper and lower surfaces of the sheet-shaped thermally conductive insulating silicone rubber thermal interface material obtained in step 4) for storage and use. 6. The method for preparing a heat-conducting and insulating silicone rubber thermal interface material as claimed in claim 4, wherein the surface treatment agent is one or more of KH550, KH560, KH570, A151, and Si-69; The softening agent is one or more of hydroxyl silicone oil, magnesium carbonate, methyl polysiloxane containing hydrolyzable groups, and polysiloxane with a low polymerization degree of 200-2000.