Method for improving pseudo hardness of heat-conducting gasket

Abstract

The invention belongs to the technical field of heat-conducting gasket processing, and particularly relates to a method for improving pseudo hardness of a heat-conducting gasket, the heat-conducting gasket is prepared from the following raw materials in parts by mass: 100 parts of vinyl silicone oil, 1-2 parts of color paste, 0.5-0.7 part of catalyst, 5-10 parts of hydrogen-containing silicone oil and 500-700 parts of mixed heat-conducting filler; the mixed heat-conducting filler comprises the following components in parts by mass: 100 parts of aluminum oxide, 40 parts of boron nitride and 5 parts of a coupling agent. The coupling agent, the aluminum oxide and the boron nitride are mixed to prepare the heat-conducting filler, and the fluorosilicone oil is introduced into the surface of the heat-conducting filler, so that the filler has a good lubricating effect, and the false hardness phenomenon of the heat-conducting gasket can be eliminated.

Description

Technical Field

[0001] The invention relates to a method for improving the pseudo-hardness of a thermally conductive gasket, and belongs to the technical field of thermally conductive gasket processing. Background Art

[0002] As a high-performance gap-filling thermal conductive material, thermal conductive gaskets are widely used in the heat transfer interface between electronic equipment and heat sinks or product housings. With the rapid development of integrated technology and assembly technology in the field of electrical and electronic technology, the volume of electronic components and logic circuits has been continuously reduced, which has put forward higher requirements on the performance of thermal conductive materials. In the processing of thermal conductive gaskets, the purpose of heat conduction is achieved by adding thermal conductive fillers. In the molding process of thermal conductive gaskets, the paste material needs to be pressed to a certain thickness first, and then heated and molded into a solid sheet. However, in the molding process of thermal conductive gaskets, the orientation of thermal conductive fillers has become an issue that cannot be ignored. Due to the obvious orientation of fillers, the thermal conductive gaskets often have false hardness. The hardness of the thermal conductive gaskets will drop significantly after rubbing them a few times. Specifically, the orientation degree of thermal conductive fillers directly affects the thermal conductivity of thermal conductive gaskets. This situation is not conducive to the performance control of the product. Therefore, in the preparation process of thermal conductive gaskets, how to control the orientation of thermal conductive fillers and avoid the appearance of false hardness of thermal conductive gaskets has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] The present invention aims at the technical problem that the existing thermally conductive gasket has pseudo-hardness due to the orientation of the thermally conductive filler, and provides a method for improving the pseudo-hardness of the thermally conductive gasket.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] A method for improving the pseudo-hardness of a thermally conductive gasket, comprising the following raw materials, measured by mass: 100 parts of vinyl silicone oil, 1-2 parts of color paste, 0.5-0.7 parts of a catalyst, 5-10 parts of hydrogenated silicone oil and 500-700 parts of a mixed thermally conductive filler;

[0006] In parts by mass, the mixed thermal conductive filler includes 100 parts of aluminum oxide, 40 parts of boron nitride and 5 parts of coupling agent.

[0007] On the basis of the above technical solution, the present invention can also make the following improvements:

[0008] Furthermore, the aluminum oxide is angular, and the average particle size of the aluminum oxide is 40 μm to 60 μm; the boron nitride is flaky, and the average particle size of the boron nitride is 3 μm to 5 μm.

[0009] Alumina and boron nitride are used as thermal conductive fillers. The raw materials are easy to obtain, the contact area is large, the cost is low, and the contact area between flaky particles and angular particles is larger, which makes it easier to improve thermal conductivity.

[0010] Further, the method specifically includes the following steps:

[0011] (1) Preparation of coupling agent;

[0012] (2) Preparation of mixed thermal conductive filler:

[0013] The coupling agent prepared in step (1) is mixed with aluminum oxide and boron nitride in proportion to prepare a mixed thermal conductive filler;

[0014] (3) Preparation of thermal conductive pads.

[0015] Furthermore, in step (1), the preparation of the coupling agent includes: mixing single-end vinyl trimethoxy silane and terminal vinyl polytrifluoropropyl methyl siloxane in a mass ratio of 1:1, taking the mixed resin as the base material, adding 0.05% to 0.2% of a catalyst, and then adding 5% to 10% of a double-end hydrogenated silicone oil, reacting at 80°C to 120°C for 30min to 40min, controlling the viscosity to 300mPa·s to 450mPa·s, to obtain a coupling agent.

[0016] Furthermore, the viscosity of the terminal vinyl-containing polytrifluoropropylmethylsiloxane is 100 mPa·s to 150 mPa·s.

[0017] Furthermore, the viscosity of the double-ended hydrogen-containing silicone oil is 90 mPa·s to 120 mPa·s, and the hydrogen content is 0.04%.

[0018] Using a lower viscosity resin can make it easier to add irregular thermally conductive fillers into the system.

[0019] Furthermore, in step (3), the preparation of the thermally conductive gasket includes: mixing all raw materials into a paste, putting the paste into a mold, pressing the paste into a 2 mm thick blank, and curing the blank at 125° C. for 30 minutes to obtain the thermally conductive gasket.

[0020] Furthermore, the viscosity of the vinyl silicone oil is 500mPa·s to 600mPa·s, and the vinyl content is 0.1% to 0.3%.

[0021] Furthermore, the viscosity of the hydrogen-containing silicone oil is 30 mPa·s to 50 mPa·s, and the active hydrogen content is 0.1% to 0.3%.

[0022] Furthermore, the catalysts are all platinum catalysts.

[0023] The beneficial effects of the present invention are as follows: the present invention adopts a coupling agent mixed with aluminum oxide and boron nitride to prepare a thermally conductive filler, and introduces fluorosilicone oil into the surface of the thermally conductive filler, so that the fillers have a good lubrication effect, and the compatibility between the filler and the matrix silicone oil is improved, so that the overall viscosity of the system is moderate, and the presence of fluorine-containing coupling agent between particles of the thermally conductive filler makes the fillers more isotropic, thereby reducing the orientation caused by the limited free movement ability of the filler due to adhesion and agglomeration, and can reduce the false hardness phenomenon of the thermally conductive gasket. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] The raw materials used in the embodiments of the present invention are from:

[0026] Terminal vinyl-containing polytrifluoropropylmethylsiloxane was purchased from Hubei Xinyuhong Biopharmaceutical Technology Co., Ltd., brand 809;

[0027] The remaining raw materials are commercially available.

[0028] Preparation of mixed thermal conductive filler:

[0029] 50 g of single-terminal vinyl trimethoxysilane and 50 g of terminal vinyl polytrifluoropropyl methylsiloxane were mixed, and the mixed resin was used as the base material, 0.1 g of catalyst was added, and then 6 g of double-terminal hydrogen silicone oil was added, and the reaction was carried out at 100° C. for 30 min, and the viscosity was controlled at 300 mPa·s to 450 mPa·s to obtain a coupling agent;

[0030] 100 parts of angular aluminum oxide, 40 parts of flake boron nitride and 5 parts of coupling agent are fully mixed to obtain a mixed thermal conductive filler.

[0031] Example 1

[0032] A method for improving the pseudo-hardness of a thermally conductive pad comprises raw materials including: 100 parts of vinyl silicone oil, 1 part of blue color paste, 0.5 parts of platinum catalyst, 5 parts of hydrogen-containing silicone oil, and 500 parts of mixed thermally conductive filler.

[0033] The silicone oil, color paste, catalyst and mixed thermal conductive filler are mixed evenly into a paste, put into a flat vulcanizer, pressed into a 2 mm thick blank, and the blank is cured at 125° C. for 30 minutes to obtain a thermal conductive gasket.

[0034] Example 2

[0035] A method for improving the pseudo-hardness of a thermally conductive pad comprises raw materials including: 100 parts of vinyl silicone oil, 2 parts of blue color paste, 0.7 parts of platinum catalyst, 10 parts of hydrogen-containing silicone oil, and 700 parts of mixed thermally conductive filler.

[0036] The silicone oil, color paste, catalyst and mixed thermal conductive filler are mixed evenly into a paste, put into a flat vulcanizer, pressed into a 2 mm thick blank, and the blank is cured at 125° C. for 30 minutes to obtain a thermal conductive gasket.

[0037] Example 3

[0038] A method for improving the pseudo-hardness of a thermally conductive pad comprises raw materials including: 100 parts of vinyl silicone oil, 1.5 parts of blue color paste, 0.6 parts of platinum catalyst, 7 parts of hydrogenated silicone oil, and 600 parts of mixed thermally conductive filler.

[0039] The silicone oil, color paste, catalyst and mixed thermal conductive filler are mixed evenly into a paste, put into a mold, pressed into a blank with a thickness of 2 mm, and the blank is cured at 125° C. for 30 minutes to obtain a thermal conductive gasket.

[0040] Comparative Example 1

[0041] Different from Example 1, the thermal conductive filler used in this comparative example is a mixture of angular aluminum oxide and flaky boron nitride, wherein the aluminum oxide is 100 parts and the boron nitride is 40 parts.

[0042] The rest is the same as in Example 1 and will not be described in detail.

[0043] Comparative Example 2

[0044] Different from Example 2, the thermal conductive filler used in this comparative example is a mixture of angular aluminum oxide and flaky boron nitride, wherein the aluminum oxide is 100 parts and the boron nitride is 40 parts.

[0045] The rest is the same as in Example 2 and will not be described in detail.

[0046] Comparative Example 3

[0047] Different from Example 3, the thermal conductive filler used in this comparative example is a mixture of angular aluminum oxide and flaky boron nitride, wherein the aluminum oxide is 100 parts and the boron nitride is 40 parts.

[0048] The rest is the same as in Example 3 and will not be described in detail.

[0049] The thermally conductive gaskets prepared in the above-mentioned embodiments and comparative examples were subjected to a vibration test, and the process of the vibration test was as follows: the prepared samples were vibrated on a vibration table at 60 times / min for 5 minutes.

[0050] The test results are shown in Table 1 below:

[0051] Table 1 Vibration test results

[0052] sample Hardness before vibration (Shore OO) Hardness after vibration (Shore OO) Example 1 42 41.6 Example 2 66 64 Example 3 54 53 Comparative Example 1 63 54 Comparative Example 2 85 73 Comparative Example 3 72 65

[0053] From the test results in Table 1 above, it can be seen that the hardness of the thermally conductive gaskets prepared by the mixed thermally conductive filler of the present invention in Examples 1-3 did not decrease significantly before and after the vibration test, indicating that no false hardness occurred. However, in Comparative Examples 1-3, which did not use the mixed thermally conductive filler of the present invention to prepare the thermally conductive gaskets, the system dispersion state was poor, the wettability of the cured product was poor, and the hardness was too high because the thermally conductive filler of the present invention was not added. Before and after the vibration test, the hardness of the thermally conductive gaskets decreased significantly, indicating that the comparative examples 1-3 had false hardness. It can be seen that the method of the present invention can eliminate the false hardness phenomenon of the thermally conductive gaskets.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the pseudo-hardness of a thermally conductive gasket, characterized in that: The following raw materials are included in parts by mass: 100 parts of vinyl silicone oil, 1-2 parts of color paste, 0.5-0.7 parts of catalyst, 5-10 parts of hydrogenated silicone oil and 500-700 parts of mixed thermal conductive filler; In parts by mass, the mixed thermal conductive filler includes 100 parts of aluminum oxide, 40 parts of boron nitride and 5 parts of coupling agent.

2. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 1, characterized in that: The aluminum oxide is angular, and the average particle size of the aluminum oxide is 40 μm to 60 μm; the boron nitride is flake-shaped, and the average particle size of the boron nitride is 3 μm to 5 μm.

3. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 2, characterized in that: The specific steps include: (1) Preparation of coupling agent; (2) Preparation of mixed thermal conductive filler: The coupling agent prepared in step (1) is mixed with aluminum oxide and boron nitride in proportion to prepare a mixed thermal conductive filler; (3) Preparation of thermal conductive pads.

4. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 3, characterized in that: In step (1), the preparation of the coupling agent comprises: mixing single-end vinyl trimethoxy silane and terminal vinyl polytrifluoropropyl methyl siloxane in a mass ratio of 1:1, taking the mixed resin as the base material, adding 0.05% to 0.2% of a catalyst, and then adding 5% to 10% of a double-end hydrogenated silicone oil, reacting at 80°C to 120°C for 30min to 40min, controlling the viscosity to 300mPa·s to 450mPa·s, and obtaining a coupling agent.

5. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 4, characterized in that: The viscosity of the terminal vinyl-containing polytrifluoropropylmethylsiloxane is 100 mPa·s to 150 mPa·s.

6. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 4, characterized in that: The viscosity of the double-ended hydrogen-containing silicone oil is 90 mPa·s to 120 mPa·s, and the hydrogen content is 0.04%.

7. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 4, characterized in that: In step (3), the preparation of the thermally conductive gasket includes: mixing all raw materials into a paste, putting the mixture into a mold, pressing the mixture into a blank with a thickness of 2 mm, and curing the blank at 125° C. for 30 minutes to obtain the thermally conductive gasket.

8. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 7, characterized in that: The viscosity of the vinyl silicone oil is 500mPa·s to 600mPa·s, and the vinyl content is 0.1% to 0.3%.

9. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 7, characterized in that: The viscosity of the hydrogen-containing silicone oil is 30mPa·s to 50mPa·s, and the active hydrogen content is 0.1% to 0.3%.

10. The method for improving the pseudo-hardness of a thermally conductive pad according to claim 7, characterized in that: The catalysts are all platinum catalysts.