Preparation method of magnesium oxide type heat-conducting gasket for improving volume resistivity stability

Abstract

The invention belongs to the technical field of heat-conducting gasket preparation processes, and particularly relates to a preparation method of a magnesium oxide type heat-conducting gasket capable of improving volume resistivity stability, the magnesium oxide type heat-conducting gasket comprises the following raw materials by mass: 100 parts of vinyl silicone oil, 0.1-0.3 part of a catalyst, 1-3 parts of hydrogen-containing silicone oil, 600-800 parts of magnesium oxide, and 300-500 parts of alumina; the magnesium oxide is subjected to surface treatment by adopting a treating agent. The magnesium oxide is subjected to surface treatment through the treating agent, so that a hydrophobic layer is formed on the surface of the magnesium oxide, magnesium oxide particles are coated with the hydrophobic layer, moisture in air is not prone to permeating into the magnesium oxide, and the magnesium oxide subjected to surface treatment is added to preparation of the heat-conducting gasket. Therefore, the volume resistivity of the heat-conducting gasket is kept stable for a long time.

Description

Technical Field

[0001] The invention relates to a method for preparing a magnesium oxide type heat-conducting gasket capable of improving the stability of volume resistivity, and belongs to the technical field of heat-conducting gasket preparation technology. Background Art

[0002] With the development of electronic technology, thermal pads are used more and more widely. With the changes in the use and storage environment of thermal pads, some types of thermal pads will absorb moisture during long-term storage, resulting in a gradual attenuation of resistivity, which brings certain instability to the client's use, especially the use and testing of the power on. Therefore, it is necessary to avoid using thermal pads with poor long-term stability of volume resistivity. However, since the volume resistivity of the thermal pad will not show obvious attenuation until several months of storage, this important indicator becomes difficult to monitor, which is unacceptable for use scenarios that require higher electrical performance. Magnesium oxide thermal pads are more prone to the phenomenon of volume resistivity attenuation during long-term storage. Therefore, it is necessary to improve the long-term stability of the volume resistivity of magnesium oxide thermal pads, so that the volume resistivity of magnesium oxide thermal pads can remain stable for a long time. Summary of the invention

[0003] The present invention aims to solve the technical problem that the existing magnesium oxide type thermally conductive gasket is prone to volume resistivity attenuation during long-term storage, and provides a method for preparing a magnesium oxide type thermally conductive gasket with improved volume resistivity stability.

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

[0005] A method for preparing a magnesium oxide type thermally conductive pad for improving the stability of volume resistivity, comprising the following raw materials in parts by mass:

[0006] 100 parts of vinyl silicone oil, 0.1-0.3 parts of catalyst, 1-3 parts of hydrogen-containing silicone oil, 600-800 parts of magnesium oxide, and 300-500 parts of aluminum oxide;

[0007] The magnesium oxide is surface treated with a treating agent.

[0008] On the basis of the above technical solution, the present invention can also make the following improvements:

[0009] Further, the preparation of the treatment agent comprises the following steps:

[0010] The treating agent is obtained by mixing single-terminal alkoxy vinyl silicone oil with dumbbell-shaped hydrogen-containing resin, adding a catalyst, and then adding double-terminal hydrogen-containing silicone oil to control the molecular weight.

[0011] Furthermore, the ratio of the single-end alkoxy vinyl silicone oil to the dumbbell-shaped hydrogen-containing resin is 30:1 to 50:1.

[0012] Furthermore, the molecular weight is controlled within the range of 3000 to 5000, and the viscosity of the treating agent is controlled within the range of 100 mPa·s to 150 mPa·s, so that the treating agent can be easily coated on the surface of the filler.

[0013] Furthermore, the structural formula of the dumbbell-shaped hydrogen-containing resin is as follows:

[0014]

[0015] Furthermore, the single-end alkoxy vinyl silicone oil has a viscosity of 40 mPa·s to 70 mPa·s and a vinyl content of 0.1% to 0.2%.

[0016] Furthermore, the viscosity of the double-ended hydrogen-containing silicone oil is 300mPa·s to 600mPa·s, and the active hydrogen content is 0.05% to 0.1%.

[0017] Further, the method specifically includes the following steps:

[0018] (1) Surface treatment of magnesium oxide: 100 parts of magnesium oxide and 3-5 parts of treatment agent are fully mixed, the temperature is raised to 60°C to 80°C, small molecules are removed by vacuuming, and the mixture is cooled naturally for later use;

[0019] (2) Preparation of thermally conductive gasket: All raw materials are mixed evenly, put into a mold, and pressed into a blank with a thickness of 2 mm. The blank is cured at a temperature of 120° C. for 30 minutes to obtain a thermally conductive gasket.

[0020] Furthermore, the particle size of the magnesium oxide is 5 μm to 15 μm.

[0021] Furthermore, the aluminum oxide is spherical, and the particle size of the aluminum oxide is 5 μm to 15 μm.

[0022] Furthermore, the viscosity of the vinyl silicone oil is 200 mPa·s to 300 mPa·s, and the vinyl content is 0.15% to 0.30% (by weight).

[0023] Furthermore, the viscosity of the hydrogen-containing silicone oil is 20 mPa·s to 60 mPa·s, and the active hydrogen content is 0.1% to 0.3% (weight fraction).

[0024] Furthermore, the catalyst is a platinum catalyst.

[0025] The beneficial effects of the present invention are as follows: the present invention performs surface treatment on magnesium oxide through a treatment agent, so that a hydrophobic layer is formed on the surface of the magnesium oxide, and the magnesium oxide particles are coated in the hydrophobic layer, so that moisture in the air is not easy to penetrate into the magnesium oxide, and the surface-treated magnesium oxide is added to the preparation of the thermally conductive gasket, so that the volume resistivity of the thermally conductive gasket remains stable for a long time. DETAILED DESCRIPTION

[0026] 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.

[0027] The raw materials used in the embodiments of the present invention are from:

[0028] Dumbbell-shaped hydrogen-containing resin, purchased from Zhejiang Runhe Silicone New Materials Co., Ltd., brand RH-XL28;

[0029] Magnesium oxide was purchased from Shinjima Chemical Industry Co., Ltd. of Japan with the brand name MSL Hebei.

[0030] The remaining raw materials are commercially available.

[0031] Preparation of treatment agent:

[0032] The single-end alkoxy vinyl silicone oil and the dumbbell-shaped hydrogen-containing resin are uniformly mixed in a ratio of 40:1, a platinum catalyst is added, and then the double-end hydrogen-containing silicone oil is added to control the number average molecular weight to 3000-5000 to obtain a treating agent, and the viscosity of the treating agent is controlled at 180mPa·s.

[0033] Surface treatment of magnesium oxide:

[0034] Mix 100 parts of magnesium oxide and 4 parts of treating agent thoroughly, select the particle size of magnesium oxide to be 8 μm, heat to 75°C, vacuum to remove small molecules, and cool naturally for use.

[0035] Example 1

[0036] A method for preparing a magnesium oxide type thermally conductive pad for improving the stability of volume resistivity. The raw materials include: 100 parts of vinyl silicone oil, 0.1 parts of platinum catalyst, 1 part of hydrogen-containing silicone oil, 600 parts of surface-treated magnesium oxide, and 300 parts of aluminum oxide.

[0037] The above raw materials, aluminum oxide and treated magnesium oxide were simply mixed evenly, and cured at 120° C. for 30 minutes to prepare a 2 mm thick thermal conductive gasket, and then the volume resistivity was tested according to ASTM D257.

[0038] Example 2

[0039] Different from Example 1, the raw materials of this example include: 100 parts of vinyl silicone oil, 0.3 parts of platinum catalyst, 3 parts of hydrogen-containing silicone oil, 800 parts of surface-treated magnesium oxide, and 500 parts of aluminum oxide.

[0040] The rest is the same as Example 1 and will not be described in detail.

[0041] Example 3

[0042] Different from Example 1, the raw materials of this example include: 100 parts of vinyl silicone oil, 0.2 parts of platinum catalyst, 2 parts of hydrogen-containing silicone oil, 700 parts of surface-treated magnesium oxide, and 400 parts of aluminum oxide.

[0043] The silicone oil catalyst and the treated magnesium oxide and aluminum oxide were simply mixed evenly, and cured at 120° C. for 30 minutes to prepare a 2 mm thick thermal conductive gasket, and then the volume resistivity was tested according to ASTM D257.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that the magnesium oxide in this comparative example is not surface treated, and the other details are the same as those in Example 1 and will not be described again.

[0046] Comparative Example 2

[0047] The difference from Example 2 is that the magnesium oxide in this comparative example is not surface treated, and the other details are the same as those in Example 2 and will not be described again.

[0048] Comparative Example 3

[0049] The difference from Example 3 is that the magnesium oxide in this comparative example is not surface treated. The other details are the same as those in Example 3 and will not be described again.

[0050] The volume resistivity test results of the above embodiments and comparative examples are as follows:

[0051] Table 1 Volume resistivity test results

[0052]

[0053]

[0054] From the results in Table 1, it can be seen that the volume resistivity of the thermally conductive pads prepared by using magnesium oxide surface-treated by a treatment agent in Examples 1 to 3 of the present invention remained stable within 12 months without any change in magnitude; while the volume resistivity of the thermally conductive pads obtained by adding only ordinary magnesium oxide in Comparative Examples 1 to 3 gradually decreased with the extension of storage time, and even decreased by 2 to 3 orders of magnitude after 12 months of storage. It can be seen that the preparation method of the present invention can effectively prevent moisture from penetrating into magnesium oxide, thereby improving the long-term stability of the volume resistivity of the thermally conductive pads.

[0055] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability, characterized in that: In parts by weight, the following raw materials are included: 100 parts of vinyl silicone oil, 0.1-0.3 parts of catalyst, 1-3 parts of hydrogen-containing silicone oil, 600-800 parts of magnesium oxide, and 300-500 parts of aluminum oxide; The magnesium oxide is surface treated with a treating agent.

2. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 1, characterized in that: The preparation of the treatment agent comprises the following steps: The single-terminal alkoxy vinyl silicone oil is mixed with a dumbbell-shaped hydrogen-containing resin, a catalyst is added, and then double-terminal hydrogen-containing silicone oil is added to control the number average molecular weight to obtain a treating agent.

3. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 2, characterized in that: The weight ratio of the single-end alkoxy vinyl silicone oil to the dumbbell-shaped hydrogen-containing resin is 30:1 to 50:

1.

4. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 3, characterized in that: The number average molecular weight is controlled within the range of 3000 to 5000, and the viscosity of the treating agent is controlled within the range of 100 mPa·s to 150 mPa·s.

5. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 4, characterized in that: The structural formula of the dumbbell-shaped hydrogen-containing resin is as follows:

6. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 5, characterized in that: The viscosity of the single-end alkoxy vinyl silicone oil is 40mPa·s to 70mPa·s, and the weight content of vinyl is 0.1% to 0.2%.

7. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 5, characterized in that: The viscosity of the double-ended hydrogen-containing silicone oil is 300mPa·s to 600mPa·s, and the weight content of active hydrogen is 0.05% to 0.1%.

8. The method for preparing a magnesium oxide type thermally conductive gasket with improved volume resistivity stability according to claim 6 or 7, characterized in that: The specific steps include: (1) Surface treatment of magnesium oxide: 100 parts of magnesium oxide and 3-5 parts of treatment agent are fully mixed, the temperature is raised to 60°C to 80°C, small molecules are removed by vacuuming, and the mixture is cooled naturally for later use; (2) Preparation of thermally conductive gasket: All raw materials are mixed evenly, put into a mold, and pressed into a blank with a thickness of 2 mm. The blank is cured at a temperature of 120° C. for 30 minutes to obtain a thermally conductive gasket.

9. The method for preparing a magnesium oxide type thermally conductive pad with improved volume resistivity stability according to claim 8, characterized in that: The particle size of the magnesium oxide is 5 μm to 15 μm.

10. The method for preparing a magnesium oxide type thermally conductive gasket with improved volume resistivity stability according to claim 8, characterized in that: The aluminum oxide is spherical, and the particle size of the aluminum oxide is 5 μm to 15 μm.

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