A highly puncture-resistant, high thermally conductive insulating sheet and its preparation method

Abstract

This invention relates to a highly puncture-resistant and thermally conductive insulating sheet, comprising a substrate and a mixture coated on the substrate. The mixture consists of the following components in parts by weight: 10-40 parts of vinyl raw rubber with a molecular weight of 350,000, 0.1-1.0 parts of curing agent, 5-15 parts of reinforcing resin, 5-10 parts of flame retardant, and 50-80 parts of thermally conductive powder. The highly puncture-resistant and thermally conductive insulating sheet material of this invention is a material with high puncture resistance, high tensile strength, and high tear strength, possessing excellent thermal conductivity and outstanding electrical insulation properties. This allows the silicone thermally conductive adhesive insulating sheet material to operate continuously at temperatures ranging from -40°C to 200°C, enabling its application in industries such as high-power power supplies, transformers, new energy vehicle battery packs, and high-power IGBT modules, as well as in the aerospace field.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive and insulating materials, and in particular to a high-puncture-resistant, high-thermal-conductivity insulating sheet and its preparation method. Background Technology

[0002] Currently, the traditional thermally conductive insulating sheets used in welding machines and large transformers are mainly thermally conductive polypropylene sheets or Mylar sheets. Due to their excellent toughness, physical strength, and electrical insulation properties, they are not easily torn during installation and can ensure that the equipment is not easily broken down by current. They are suitable for many low-power electrical applications. However, because thermally conductive polypropylene and Mylar sheets have low thermal conductivity, they do not have good heat dissipation capabilities. When high heat is generated during equipment operation, they cannot dissipate heat in time. Prolonged use will reduce the lifespan of components and may even lead to safety accidents. Therefore, this invention... In the future, a high-puncture-resistant, high-thermal-conductivity insulating sheet material will replace traditional insulating materials. This high-thermal-conductivity insulating sheet is mainly composed of silicone rubber, and its thermal conductivity is several times that of polypropylene sheets and Mylar sheets. It has good high and low temperature resistance and can work continuously at temperatures ranging from -40 to 200°C. The excellent physical strength and electrical insulation properties of the silicone material itself ensure the safe use of the original device. Its excellent puncture resistance and tear strength prevent short circuits caused by breakage during the fixing and use of MOS blocks and heat sinks, improving safety, insulation and reliability. Summary of the Invention

[0003] The present invention provides a high puncture resistance and high thermal conductivity insulating sheet, comprising a substrate and a mixture coated on the substrate, the mixture being composed of the following components in parts by weight: 10-40 parts of vinyl raw rubber with a molecular weight of 350,000, 0.1-1.0 parts of curing agent, 5-15 parts of reinforcing resin, 5-10 parts of flame retardant, and 50-80 parts of thermally conductive powder.

[0004] Furthermore, the substrate is a glass fiber cloth with a thickness of 0.05 mm. The tensile strength of the glass fiber cloth in both the warp and weft directions is greater than or equal to 1250 N / 50 mm, the alkali resistance tensile breaking force retention rate is greater than 90%, and the weight per square meter is greater than or equal to 160 grams. After meeting the above conditions, the substrate is not easy to break during production.

[0005] Furthermore, the reinforcing resin is vinyl MQ resin with a viscosity of 100,000 cps, and CX-3900 resin from Guangdong Chenxi Organosilicon Materials Co., Ltd., which has excellent toughness and can meet the requirements for use.

[0006] The curing agent is benzoyl peroxide; the flame retardant is modified aluminum hydroxide powder with a particle size of 20 μm, specifically H-32 aluminum hydroxide from Showa Chemical Co., Ltd. of Japan.

[0007] The thermally conductive powder is alumina powder with a particle size of 20um to 0.5um, mixed at a particle size weight ratio of 3:1 and then added.

[0008] The present invention also relates to the preparation steps of the above-mentioned insulating sheet as follows: the base resin, reinforcing resin, flame retardant and thermally conductive powder are added to the internal mixer in sequence at a speed of 80 rpm and a temperature of 120°C. The mixture is vacuum-mixed for 90 minutes. After cooling, the mixture is mixed evenly using an open mill. A curing agent is added and the mixture is mixed evenly again. Calendering is then started. A 5-roll calender production line is used to press the sheet. The base film is a PET release film with a release force of 5g. The substrate is an alkaline glass fiber cloth with a thickness of 0.05mm. The total thickness of the insulating sheet is controlled at 0.45mm. The sheet is cured using a high-temperature automatic rotary drum molding machine. The resulting sheet is an insulating sheet roll.

[0009] The beneficial effects of this invention are: the high puncture-resistant thermally conductive insulating sheet material of this invention is a material with high puncture resistance, high tensile strength and high tear strength, with excellent thermal conductivity and excellent electrical insulation properties, enabling the silicone thermally conductive adhesive insulating sheet material to work continuously at temperatures from -40 to 200°C, and can be applied to industries such as high-power power supplies, transformers, new energy vehicle battery packs, and high-power IGBT modules, as well as aerospace fields. Detailed Implementation

[0010] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0011] Example 1

[0012] A high-puncture-resistant and high-thermal-conductivity insulating sheet is provided, with a base material of glass fiber cloth with a thickness of 0.05 mm. The tensile strength of the glass fiber cloth in both the warp and weft directions is greater than or equal to 1250 N / 50 mm, the alkali-resistant tensile breaking strength retention rate is greater than 90%, and the weight per square meter is greater than or equal to 160 grams. The base resin is 20 parts of vinyl ester raw rubber with a molecular weight of 350,000, the curing agent is 0.7 parts of benzoyl peroxide, the reinforcing resin is 5 parts of vinyl MQ resin, the flame retardant is 8 parts of modified aluminum hydroxide powder, and the thermally conductive powder is alumina with particle sizes of 10 μm and 0.5 μm. After mixing them at a weight ratio of 3:1, the total mixture is 60 parts.

[0013] Example 2

[0014] A high-puncture-resistant and high-thermal-conductivity insulating sheet is provided. The substrate is fiberglass cloth with a thickness of 0.05 mm. The tensile strength of the fiberglass cloth in both the warp and weft directions is greater than or equal to 1250 N / 50 mm. The alkali-resistant tensile breaking strength retention rate is greater than 90%. The weight per square meter is greater than or equal to 160 grams. The base resin is 10 parts of vinyl MQ resin with a molecular weight of 350,000. The curing agent is 0.5 parts of benzoyl peroxide. The reinforcing resin is 10 parts of vinyl MQ resin. The flame retardant is 8 parts of modified aluminum hydroxide powder. The thermally conductive powder is alumina with particle sizes of 20 μm and 5 μm. After being mixed evenly at a weight ratio of 3:1, a total of 60 parts of the powder are added.

[0015] Example 3

[0016] A highly puncture-resistant and thermally conductive insulating sheet is disclosed. The substrate is fiberglass cloth with a thickness of 0.05 mm. The tensile strength of the fiberglass cloth in both the warp and weft directions is greater than or equal to 1250 N / 50 mm. The alkali-resistant tensile breaking strength retention rate is greater than 90%, and the weight per square meter is greater than or equal to 160 grams. The base resin is 15 parts of vinyl ester raw rubber with a molecular weight of 350,000; the curing agent is 0.5 parts of benzoyl peroxide; the reinforcing resin is 5 parts of vinyl MQ resin; the flame retardant is 8 parts of modified aluminum hydroxide powder; and the thermally conductive powder is modified alumina with particle sizes of 10 μm and 2 μm, mixed evenly at a weight ratio of 3:1, totaling 60 parts.

[0017] The preparation method of a high puncture resistance high insulation sheet in Examples 1-3 is as follows: the base resin, reinforcing resin, flame retardant and thermally conductive powder are added to a mixer in sequence at a speed of 80 rpm and a temperature of 120°C. The mixture is vacuum-mixed for 90 minutes. After cooling, the mixture is mixed evenly using a two-roll mill. A curing agent is added and the mixture is mixed evenly again. Calendering is then started. A 5-roll calender production line is used to press the sheet. The base film is a PET release film with a release force of 5g. The substrate is a 0.05mm thick alkaline glass fiber cloth. The total thickness of the insulation sheet is controlled at 0.45mm. The sheet is cured using a high-temperature automatic rotary drum molding machine. The resulting insulation sheet roll is a high-temperature automatic rotary drum molding machine.

[0018] The high-puncture-resistant insulating sheets obtained in Examples 1-3 were tested for relevant indicators, as shown in Table 1. The data in the table show that the self-adhesive silicone thermally conductive insulating sheets of Examples 1-3 exhibit good thermal stability and mechanical properties.

[0019] Table 1. Performance Tests of High-Puncture-Resistant Insulating Sheets in Examples 1-3

[0020]

[0021] The experimental comparison data shows that traditional thermally conductive polypropylene sheets and Mylar sheets have the same physical and electrical properties as silicone materials. However, due to the inherent limitations of the materials, their thermal conductivity cannot be improved by adding a large amount of thermally conductive filler. The thermally conductive insulating sheet of this invention has relatively ideal puncture resistance and excellent thermal conductivity, and has a wider range of applications.

[0022] 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 within the protection scope of the present invention.

Claims

1. A highly puncture-resistant, highly thermally conductive insulating sheet, characterized in that, It includes a substrate and a mixture applied to the substrate, the mixture being composed of the following components in parts by weight: 10-40 parts of vinyl raw rubber with a molecular weight of 350,000, 0.1-1.0 parts of curing agent, 5-15 parts of reinforcing resin, 5-10 parts of flame retardant, and 50-80 parts of thermally conductive powder. The substrate is fiberglass cloth with a thickness of 0.05 mm. The tensile strength of the fiberglass cloth in both the warp and weft directions is greater than or equal to 1250 N / 50 mm, the alkali resistance tensile breaking strength retention rate is greater than 90%, and the weight per square meter is greater than or equal to 160 grams. The reinforcing resin is vinyl MQ resin with a viscosity of 100,000 cps. The curing agent is benzoyl peroxide. The flame retardant is modified aluminum hydroxide powder with a particle size of 20 μm. The thermally conductive powder is alumina powder with particle sizes of 20 μm and 5 μm, which are mixed evenly at a weight ratio of 3:1 and then added.

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