Preparation method of ultra-soft low-oil-permeability 3W heat-conducting gasket

Abstract

The invention relates to the technical field of preparation of heat-conducting gaskets, in particular to a preparation method of an ultra-soft low-oil-permeability 3W heat-conducting gasket. Comprising the following steps: selecting low-volatility vinyl-terminated silicone oil and low-volatility side hydrogen-containing silicone oil as hydrosilylation reaction base materials; single-ended vinyl-trimethylsilyl siloxane is selected as a treating agent; high-thermal-conductivity single crystal aluminum oxide is selected as a thermal conductive filler; the materials are mixed and subjected to a hydrosilylation reaction, and the crosslinking density is controlled, so that the hardness of the heat-conducting gasket is smaller than shore oo 45, and the oil penetration rate is lower than 0.5%. The problem that the hardness and the oil penetration rate cannot be met at the same time in the prior art is solved, the reliability and the stability of the heat-conducting gasket in practical application are remarkably improved, and the heat-conducting gasket has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of thermal conductive pad preparation, and in particular to a method for preparing a 3W thermal conductive pad with ultra-soft low-penetration oil. Background Art

[0002] Thermal pads are materials used to transfer heat and fill the gap between the heat source and the heat sink. They are widely used in electronic equipment, military products, optical communications, LEDs, power supplies and other industries. As electronic equipment gradually develops towards miniaturization and integration, the performance requirements of thermal pads are becoming higher and higher, especially for the control of hardness and oil permeability.

[0003] The thermal pads currently used in the market face two major problems: they cannot meet the requirements of ultra-soft hardness and low oil permeability at the same time. Specifically, (1) They cannot meet the requirements of ultra-soft hardness while meeting the requirements of low oil permeability: Some thermal pads reduce the oil permeability by reducing the number of unreacted free organic molecules, but this will increase the hardness of the pad and cannot meet the ultra-soft requirement. (2) They cannot meet the requirements of low oil permeability while meeting the ultra-soft hardness: Other thermal pads achieve the ultra-soft effect by reducing the cross-linking density, but this will result in more free organic molecules, thereby increasing the oil permeability.

[0004] The oil seepage of thermal pads can cause a variety of problems in practical applications, including: (1) Electrostatic breakdown: Oil stains can easily absorb dust in the air, causing electrostatic breakdown. (2) Poor contact: When oil stains flow to switch components, they can easily cause poor contact. (3) Pollution of optical components: Oil stains can pollute optical components and affect their performance. (4) Corrosion of the silicone package of the chip: Oil stains can corrode the silicone package of the chip, causing the chip to fail. Summary of the invention

[0005] The present invention provides a method for preparing an ultra-soft, low-oil-permeability 3W thermally conductive gasket. By selecting low-volatile end vinyl silicone oil and low-volatile side hydrogen-containing silicone oil as a base material, using single-end vinyl-trimethylsilylsiloxane as a treating agent, and filling high thermal conductivity single crystal alumina as a thermally conductive filler, the problem that hardness and oil permeability cannot be met at the same time in the prior art is solved, and the reliability and stability of the thermally conductive gasket in practical applications are significantly improved, and the method has broad application prospects.

[0006] The technical solution adopted by the present invention is: a method for preparing a 3W thermal conductive pad with ultra-soft low-penetration oil, comprising the following steps:

[0007] Step 1: Select low-volatile end vinyl silicone oil and low-volatile side hydrogen-containing silicone oil as the substrate for the hydrosilylation reaction;

[0008] Step 2: Selecting single-end vinyl-trimethylsilylsiloxane as a treating agent;

[0009] Step 3: Select high thermal conductivity single crystal alumina as thermal conductive filler;

[0010] Step 4: Mix the above materials, perform a hydrosilane addition reaction, and control the cross-linking density so that the hardness of the thermal conductive gasket is less than shore oo 45 and the oil permeability is less than 0.5%.

[0011] As a further improvement of the present invention, the weight loss of the low-volatile end vinyl silicone oil and the low-volatile side hydrogen-containing silicone oil after being baked at a constant temperature of 150° C. for 24 hours is less than 0.05%.

[0012] As a further improvement of the present invention, the single-terminated vinyl-trimethylsilyl siloxane treating agent is used to eliminate hydroxyl groups on the surface of the thermal conductive filler and participate in the hydrosilylation reaction to reduce the presence of free treating agent molecules.

[0013] As a further improvement of the present invention, the thermal conductive filler comprises alumina powders of different particle sizes, wherein the particle size of alumina 1 is less than 1 um, the particle size of alumina 2 is 10 um, and the particle size of alumina 3 is 60 um.

[0014] As a further improvement of the present invention, the materials include, by weight: 90-100 parts of low-volatile end vinyl silicone oil, 1-3 parts of low-volatile side hydrogen-containing silicone oil, 1-3 parts of single-end vinyl-trimethylsilyl siloxane treatment agent, 80-120 parts of aluminum oxide 1, 380-420 parts of aluminum oxide 2, and 480-520 parts of aluminum oxide 3.

[0015] As a further improvement of the present invention, the viscosity of the low-volatile end-vinyl silicone oil is 500cps; the viscosity of the low-volatile side hydrogen-containing silicone oil is 50cps; the viscosity of the single-end vinyl-trimethylsilyl siloxane treatment agent is 50cps

[0016] As a further improvement of the present invention, the hydrosilylation reaction is carried out in a temperature range of 120-150° C. and the reaction time is 2-4 hours.

[0017] Beneficial effects of the present invention: (1) Reducing oil permeation rate: The present invention can effectively reduce the free organic molecules in the thermal conductive gasket by selecting low-volatile end vinyl silicone oil and low-volatile side hydrogen silicone oil as the base material, and using single-end vinyl-trimethylsilylsiloxane as the treating agent, so that the oil permeation rate of the prepared thermal conductive gasket can be lower than 0.5%, which significantly reduces the occurrence of oil permeation.

[0018] (2) Maintaining ultra-soft hardness: The present invention precisely controls the cross-linking density of the hydrosilylation reaction so that the prepared thermally conductive gasket can maintain a hardness less than shore oo 45, meeting the ultra-soft requirement, making the thermally conductive gasket softer during installation and use, and better able to adapt to irregular surfaces, thereby improving heat conduction efficiency.

[0019] (3) Improving thermal conductivity: The present invention uses high thermal conductivity single crystal alumina as the thermal conductive filler, and alumina powders of different particle sizes are reasonably matched in the formula, so that the thermal conductivity coefficient of the thermal conductive gasket reaches above 3.0W / mK, which significantly improves the thermal conductivity and meets the heat dissipation requirements of high-performance electronic equipment.

[0020] (4) Solved the problems caused by oil seepage of thermal gaskets in practical applications. Specifically, ①. Electrostatic breakdown: Due to the significant reduction in oil seepage rate, the phenomenon of oil stains absorbing dust in the air is reduced, thereby reducing the risk of electrostatic breakdown. ②. Poor contact: The oil seepage phenomenon on the surface of the thermal gasket is reduced, avoiding the poor contact problem caused by oil stains flowing to the switching device, and improving the stability and reliability of the equipment. ③. Pollution of optical devices: The reduction in oil seepage rate reduces the pollution of optical devices by oil stains, ensuring that the performance of optical devices is not affected. ④. Corrosion of the silicone package of the chip: The reduction in oil seepage rate effectively prevents the corrosion of the silicone package of the chip by oil stains, extending the service life of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of low-volatile vinyl-terminated silicone oil in a method for preparing a 3W thermally conductive pad with ultra-soft and low-permeability oil of the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of low-volatile side hydrogen-containing silicone oil in a method for preparing a 3W thermal conductive pad with ultra-soft low-permeability oil of the present invention;

[0023] Figure 3 It is a schematic diagram of the structure of single-terminal vinyl-trimethylsilylsiloxane in a method for preparing a 3W thermally conductive gasket with ultra-soft low oil permeability of the present invention;

[0024] Figure 4 It is a simplified formula of the hydrosilylation reaction of a method for preparing a 3W thermally conductive gasket with ultra-soft low permeability oil of the present invention;

[0025] Figure 5 It is a reaction principle diagram of a method for preparing a 3W thermal conductive gasket with ultra-soft low-permeability oil according to the present invention. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] The present invention provides a method for preparing a 3W thermally conductive pad with ultra-soft low-penetration oil, comprising the following steps:

[0028] Step 1: Select low-volatile end vinyl silicone oil and low-volatile side hydrogen silicone oil as the substrate for the hydrosilylation reaction, and the weight loss of the low-volatile end vinyl silicone oil and the low-volatile side hydrogen silicone oil after constant temperature baking at 150° C. for 24 hours is less than 0.05%;

[0029] Step 2: Selecting single-terminal vinyl-trimethylsilyl siloxane as a treating agent, the single-terminal vinyl-trimethylsilyl siloxane treating agent is used to eliminate the hydroxyl groups on the surface of the thermal conductive filler and participate in the hydrosilylation reaction to reduce the presence of free treating agent molecules;

[0030] Step 3: Select high thermal conductivity single crystal alumina as a thermal conductive filler, the thermal conductive filler includes alumina powders of different particle sizes, wherein the particle size of alumina 1 is less than 1um, the particle size of alumina 2 is 10um, and the particle size of alumina 3 is 60um;

[0031] Step 4: Mix the above materials and perform a hydrosilylation reaction to control the crosslinking density. The hydrosilylation reaction is performed in a temperature range of 120-150° C. for 2-4 hours, so that the hardness of the thermal conductive gasket is less than shore oo45 and the oil permeability is less than 0.5%.

[0032] The materials in the present invention include, by weight: 90-100 parts of low-volatile end-vinyl silicone oil with a viscosity of 500cps, 1-3 parts of low-volatile side hydrogen-containing silicone oil with a viscosity of 50cps, 1-3 parts of single-end vinyl-trimethylsilyl siloxane treatment agent with a viscosity of 50cps, 80-120 parts of aluminum oxide 1, 380-420 parts of aluminum oxide 2, and 480-520 parts of aluminum oxide 3.

[0033] Preparation and testing were carried out according to the above method. The test cases included Examples 1-8. After preparation, the obtained thermal conductive gasket was subjected to performance tests, including thermal conductivity, oil permeability, and hardness. The specific test cases and performance test results are shown in the following table.

[0034]

[0035]

[0036] It can be seen from the above table that when ordinary vinyl silicone oil, ordinary hydrogen-containing silicone oil or silane treating agent that has not been stripped is used in the formula, the oil permeation rate cannot meet the requirement of <0.5%; only when the formula of low-volatile vinyl silicone oil, low-volatile hydrogen-containing silicone oil and siloxane treating agent is used (Example 1), the oil permeation rate can meet the requirement of <0.5%.

[0037] In summary, the thermal conductive pad product prepared by the method for preparing a super-soft low-oil permeability 3W thermal conductive pad of the present invention solves the problem that the hardness and oil permeability cannot be satisfied at the same time in the prior art, and also significantly improves the thermal conductivity and reliability of the thermal conductive pad, and has important application value and broad market prospects. It is particularly suitable for military products, optical communications, LED, power supply and other industries, and is expected to play an important role in the heat dissipation field of high-performance electronic equipment.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil, characterized in that: The following steps are involved: Step 1: Select low-volatile end vinyl silicone oil and low-volatile side hydrogen silicone oil as the substrate for hydrosilylation reaction; Step 2: Selecting single-end vinyl-trimethylsilylsiloxane as a treating agent; Step 3: Select high thermal conductivity single crystal alumina as thermal conductive filler; Step 4: Mix the above materials, perform a hydrosilylation reaction, and control the cross-linking density so that the hardness of the thermal conductive gasket is less than shore oo 45 and the oil permeability is less than 0.5%.

2. The method for preparing a 3W thermally conductive pad with ultra-soft low permeability oil according to claim 1, characterized in that: The weight loss of the low-volatile end vinyl silicone oil and the low-volatile side hydrogen-containing silicone oil after being baked at a constant temperature of 150° C. for 24 hours is less than 0.05%.

3. The method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil according to claim 1, characterized in that: The single-terminal vinyl-trimethylsilyl siloxane treating agent is used to eliminate the hydroxyl groups on the surface of the thermal conductive filler and participate in the hydrosilylation reaction, thereby reducing the presence of free treating agent molecules.

4. The method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil according to claim 1, characterized in that: The thermal conductive filler includes aluminum oxide powders of different particle sizes, wherein the particle size of aluminum oxide 1 is less than 1 um, the particle size of aluminum oxide 2 is 10 um, and the particle size of aluminum oxide 3 is 60 um.

5. The method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil according to claim 1, characterized in that: The materials include, by weight: 90-100 parts of low-volatile end vinyl silicone oil, 1-3 parts of low-volatile side hydrogen-containing silicone oil, 1-3 parts of single-end vinyl-trimethylsilyl siloxane treatment agent, 80-120 parts of aluminum oxide 1, 380-420 parts of aluminum oxide 2, and 480-520 parts of aluminum oxide 3.

6. The method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil according to claim 1, characterized in that: The viscosity of the low-volatile vinyl-terminated silicone oil is 500 cps; the viscosity of the low-volatile hydrogen-containing silicone oil is 50 cps; and the viscosity of the single-terminated vinyl-trimethylsilyl siloxane treating agent is 50 cps.

7. The method for preparing a 3W thermally conductive pad with ultra-soft low-permeability oil according to claim 1, characterized in that: The hydrosilylation reaction is carried out in a temperature range of 120-150° C. and the reaction time is 2-4 hours.

Images