High-thermal-conductivity heat-conducting silica gel sheet and preparation method thereof

Abstract

The invention relates to the technical field of preparation of heat-conducting silica gel sheets, and discloses a high-heat-conductivity heat-conducting silica gel sheet which comprises the following raw materials in parts by weight: 90 parts of silicone rubber, 40-50 parts of heat-conducting filler, 1-5 parts of a reinforcing agent, 1-3 parts of an anti-aging agent, 1-3 parts of an antioxidant, 2-3 parts of a cross-linking agent, 3-6 parts of a flame retardant and 1-2 parts of a catalyst. The silicon rubber is organic silicon rubber; the heat-conducting filler is graphite and aluminum oxide, and the ratio of the graphite to the aluminum oxide is 1: 2. When the heat-conducting silica gel sheet is prepared, the mechanical property and the heat resistance of the heat-conducting silica gel sheet can be improved by adding the reinforcing agent, and the weather resistance and the aging resistance of the heat-conducting silica gel sheet can be enhanced by the anti-aging agent, so that the heat-conducting silica gel sheet can be used outdoors or in a severe environment; by using the antioxidant, the oxidation resistance of the heat-conducting silica gel sheet can be improved, the service life of the heat-conducting silica gel sheet can be prolonged, and by using the flame retardant, the flame retardance of the heat-conducting silica gel sheet can be improved, and the safety of the heat-conducting silica gel sheet at high temperature is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of thermally conductive silicone sheets, in particular to a thermally conductive silicone sheet with high thermal conductivity and a preparation method thereof. Background Art

[0002] High thermal conductivity thermal silicone sheet is a thin sheet product made of thermal conductive silicone material. It has excellent thermal conductivity, good insulation, excellent fire resistance, good cushioning, controllable self-adhesion, optional thickness, adjustable color, easy construction, stable quality and other characteristics, making thermal conductive silicone sheet have broad application prospects in many fields.

[0003] A Chinese patent discloses a thermally conductive silicone sheet and a preparation method thereof (Announcement No. CN115584129A). The preparation materials of the patented technology include the following components: 50-80 parts of silicone rubber, 30-45 parts of graphene, 15-20 parts of dispersant, 0.1-5 parts of coupling agent, 0.01-10 parts of curing agent, and 3-15 parts of fiber filler; wherein the dispersant includes one or more of polyvinyl alcohol, polyamide, polyvinyl acetate, polyurethane and polyacrylate. The technical solution of the present invention improves the thermal conductivity of the thermally conductive silicone sheet.

[0004] However, the existing thermally conductive silicone sheets only serve to improve the production efficiency of thermally conductive silicone sheets during the preparation process, and their flame retardant properties are poor, which can easily cause fires and property losses, and are easily affected by external factors during use, leading to accelerated aging and oxidation, which reduces their service life. Therefore, those skilled in the art provide a high thermal conductivity thermally conductive silicone sheet and a preparation method thereof to solve the problems raised in the above background technology. Summary of the invention

[0005] The object of the present invention is to provide a high thermal conductivity thermally conductive silicone sheet and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high thermal conductivity thermally conductive silicone sheet, comprising the following raw materials in parts by weight: 90 parts of silicone rubber, 40-50 parts of thermally conductive filler, 1-5 parts of reinforcing agent, 1-3 parts of anti-aging agent, 1-3 parts of antioxidant, 2-3 parts of cross-linking agent, 3-6 parts of flame retardant, and 1-2 parts of catalyst;

[0008] The silicone rubber is organic silicone rubber;

[0009] The thermal conductive filler is graphite and alumina, wherein the ratio of graphite to alumina is 1:2.

[0010] As a further solution of the present invention: the reinforcing agent comprises a metal powder filler, a metal oxide and an inorganic non-metal, wherein the ratio of the metal powder filler, the metal oxide and the inorganic non-metal is 1:0.8:0.7;

[0011] The metal powder filler is copper powder or aluminum powder, the metal oxide is aluminum oxide or magnesium oxide, and the inorganic non-metal is graphite or silicon carbide.

[0012] As a further embodiment of the present invention, the anti-aging agent is benzophenone-p-diazahaloalkane or butylhydroxymethylbenzamide, and the antioxidant is tert-butyl-p-toluic acid or 2,6-di-tert-butyl-4-methylphenol.

[0013] As a further solution of the present invention: the crosslinking agent is composed of an organic silicon crosslinking agent and an inorganic silicon crosslinking agent, wherein the ratio of the organic silicon crosslinking agent to the inorganic silicon crosslinking agent is 0.4:0.6,

[0014] The organosilicon crosslinking agent is one of polydimethylsiloxane or siloxane and epoxy crosslinking agent;

[0015] The inorganic silicon cross-linking agent is one of silicon dioxide, silicon trioxide or silicate.

[0016] As a further solution of the present invention: the flame retardant is magnesium hydroxide and aluminum hydroxide, wherein the ratio of magnesium hydroxide to aluminum hydroxide is 0.6:0.4.

[0017] As a further solution of the present invention: the catalyst is graphene or aluminum oxide.

[0018] As a further solution of the present invention: the preparation method of the high thermal conductivity thermally conductive silicone sheet comprises the following steps:

[0019] S1. Raw material preparation: First, select organic silicone with high plasticity and fluidity as the basic material, and select thermal conductive fillers, reinforcing agents, anti-aging agents, antioxidants, cross-linking agents, flame retardants and catalysts in a certain proportion;

[0020] S2. Raw material stirring and degassing: Pour the prepared raw materials into the mixing drum and stir the raw materials fully through mechanical equipment. After stirring, let the mixture stand for a period of time and then perform vacuum extraction to expel the air mixed in during stirring to avoid bubbles during the molding process;

[0021] S3, molding and vulcanization:

[0022] S31: pouring the stirred raw materials into a molding die, and rolling them through a calender to achieve a desired thickness;

[0023] S32: placing the calendered silicone sheet into a vulcanizer for high-temperature vulcanization treatment to improve physical properties;

[0024] S33: vulcanizing the vulcanized silicone sheet again in a vulcanizer to further improve the performance of the silicone sheet;

[0025] S4, cutting and trimming: cutting the vulcanized silicone sheet to obtain a thermally conductive silicone sheet of a desired size and shape, and trimming the cut silicone sheet to remove burrs and uneven parts;

[0026] S5. Finished product inspection: The cut and trimmed thermal conductive silicone sheet is subjected to a thermal conductivity test to ensure that it meets the requirements.

[0027] As a further solution of the present invention: the stirring time in S2 is 30-40 minutes, the first vulcanization time in S3 is 10-30 minutes, the second vulcanization time is 15-20 minutes, and the temperature of the two vulcanizations is 150°C-200°C.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: the mechanical properties and heat resistance of the thermally conductive silicone sheet of the present invention can be improved by adding a reinforcing agent during preparation, the weather resistance and aging resistance of the thermally conductive silicone sheet can be enhanced by an anti-aging agent, so that the thermally conductive silicone sheet can be used outdoors or in harsh environments, the antioxidant can improve the antioxidant properties of the thermally conductive silicone sheet and extend its service life, the cross-linking agent can promote the cross-linking of the internal structure of the thermally conductive silicone sheet and improve its bonding performance and heat resistance, the flame retardant can improve the flame retardant properties of the thermally conductive silicone sheet and ensure its safety at high temperatures, and finally, the addition of a catalyst can accelerate the curing process of the thermally conductive silicone sheet and improve production efficiency. The addition of these additives can significantly improve the comprehensive performance of the thermally conductive silicone sheet, making it more adaptable to various complex application scenarios and meeting the needs of electronic products, automotive parts, industrial equipment and other fields for high-performance heat dissipation materials. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] Please refer to the first embodiment of the present invention.

[0031] A high thermal conductivity thermally conductive silicone sheet, comprising the following raw materials in parts by weight: 90 parts of silicone rubber, 40 parts of thermally conductive filler, 1 part of reinforcing agent, 1 part of anti-aging agent, 1 part of antioxidant, 2 parts of cross-linking agent, 3 parts of flame retardant, and 1 part of catalyst;

[0032] Silicone rubber is organic silicone rubber;

[0033] The thermal conductive filler is graphite and alumina, wherein the ratio of graphite to alumina is 1:2.

[0034] Specifically, in this embodiment, the reinforcing agent includes metal powder filler, metal oxide and inorganic non-metal, wherein the ratio of metal powder filler, metal oxide and inorganic non-metal is 1:0.8:0.7;

[0035] The metal powder filler is copper powder or aluminum powder, the metal oxide is aluminum oxide or magnesium oxide, and the inorganic non-metal is graphite or silicon carbide.

[0036] Specifically, in this embodiment, the anti-aging agent is benzophenone or butyl hydroxymethylbenzamide, and the antioxidant is tert-butyl p-toluic acid or 2,6-di-tert-butyl-4-methylphenol.

[0037] Specifically, in this embodiment, the crosslinking agent is composed of an organic silicon crosslinking agent and an inorganic silicon crosslinking agent, wherein the ratio of the organic silicon crosslinking agent to the inorganic silicon crosslinking agent is 0.4:0.6.

[0038] The organosilicon crosslinking agent is polydimethylsiloxane or one of siloxane and epoxy crosslinking agent;

[0039] The inorganic silicon crosslinking agent is one of silicon dioxide, silicon trioxide or silicate.

[0040] Specifically in this embodiment, the flame retardant is magnesium hydroxide and aluminum hydroxide, wherein the ratio of magnesium hydroxide to aluminum hydroxide is 0.6:0.4.

[0041] Specifically in this embodiment, the catalyst is graphene or aluminum oxide.

[0042] Embodiment 2

[0043] A high thermal conductivity thermally conductive silicone sheet, comprising the following raw materials in parts by weight: 90 parts of silicone rubber, 45 parts of thermally conductive filler, 3 parts of reinforcing agent, 2 parts of anti-aging agent, 2 parts of antioxidant, 2 parts of cross-linking agent, 4 parts of flame retardant, and 1 part of catalyst;

[0044] Silicone rubber is organic silicone rubber;

[0045] The thermal conductive filler is graphite and alumina, wherein the ratio of graphite to alumina is 1:2.

[0046] Specifically, in this embodiment, the reinforcing agent includes metal powder filler, metal oxide and inorganic non-metal, wherein the ratio of metal powder filler, metal oxide and inorganic non-metal is 1:0.8:0.7;

[0047] The metal powder filler is copper powder or aluminum powder, the metal oxide is aluminum oxide or magnesium oxide, and the inorganic non-metal is graphite or silicon carbide.

[0048] Specifically, in this embodiment, the anti-aging agent is benzophenone or butyl hydroxymethylbenzamide, and the antioxidant is tert-butyl p-toluic acid or 2,6-di-tert-butyl-4-methylphenol.

[0049] Specifically, in this embodiment, the crosslinking agent is composed of an organic silicon crosslinking agent and an inorganic silicon crosslinking agent, wherein the ratio of the organic silicon crosslinking agent to the inorganic silicon crosslinking agent is 0.4:0.6.

[0050] The organosilicon crosslinking agent is polydimethylsiloxane or one of siloxane and epoxy crosslinking agent;

[0051] The inorganic silicon crosslinking agent is one of silicon dioxide, silicon trioxide or silicate.

[0052] Specifically in this embodiment, the flame retardant is magnesium hydroxide and aluminum hydroxide, wherein the ratio of magnesium hydroxide to aluminum hydroxide is 0.6:0.4.

[0053] Specifically in this embodiment, the catalyst is graphene or aluminum oxide.

[0054] Embodiment 3

[0055] A high thermal conductivity thermally conductive silicone sheet, comprising the following raw materials in parts by weight: 90 parts of silicone rubber, 50 parts of thermally conductive filler, 5 parts of reinforcing agent, 3 parts of anti-aging agent, 3 parts of antioxidant, 3 parts of cross-linking agent, 6 parts of flame retardant, and 2 parts of catalyst;

[0056] Silicone rubber is organic silicone rubber;

[0057] The thermal conductive filler is graphite and alumina, wherein the ratio of graphite to alumina is 1:2.

[0058] Specifically, in this embodiment, the reinforcing agent includes metal powder filler, metal oxide and inorganic non-metal, wherein the ratio of metal powder filler, metal oxide and inorganic non-metal is 1:0.8:0.7;

[0059] The metal powder filler is copper powder or aluminum powder, the metal oxide is aluminum oxide or magnesium oxide, and the inorganic non-metal is graphite or silicon carbide.

[0060] Specifically, in this embodiment, the anti-aging agent is benzophenone or butyl hydroxymethylbenzamide, and the antioxidant is tert-butyl p-toluic acid or 2,6-di-tert-butyl-4-methylphenol.

[0061] Specifically, in this embodiment, the crosslinking agent is composed of an organic silicon crosslinking agent and an inorganic silicon crosslinking agent, wherein the ratio of the organic silicon crosslinking agent to the inorganic silicon crosslinking agent is 0.4:0.6.

[0062] The organosilicon crosslinking agent is polydimethylsiloxane or one of siloxane and epoxy crosslinking agent;

[0063] The inorganic silicon crosslinking agent is one of silicon dioxide, silicon trioxide or silicate.

[0064] Specifically in this embodiment, the flame retardant is magnesium hydroxide and aluminum hydroxide, wherein the ratio of magnesium hydroxide to aluminum hydroxide is 0.6:0.4.

[0065] Specifically in this embodiment, the catalyst is graphene or aluminum oxide.

[0066] Embodiment 4

[0067] The method for preparing a high thermal conductivity thermally conductive silicone sheet comprises the following steps:

[0068] S1. Raw material preparation: First, select organic silicone with high plasticity and fluidity as the basic material, and select thermal conductive fillers, reinforcing agents, anti-aging agents, antioxidants, cross-linking agents, flame retardants and catalysts in a certain proportion;

[0069] S2. Raw material stirring and degassing: Pour the prepared raw materials into the mixing drum and stir the raw materials fully through mechanical equipment. After stirring, let the mixture stand for a period of time and then perform vacuum extraction to expel the air mixed in during stirring to avoid bubbles during the molding process;

[0070] S3, molding and vulcanization:

[0071] S31: pouring the stirred raw materials into a molding die, and rolling them through a calender to achieve a desired thickness;

[0072] S32: placing the calendered silicone sheet into a vulcanizer for high-temperature vulcanization treatment to improve physical properties;

[0073] S33: vulcanizing the vulcanized silicone sheet again in a vulcanizer to further improve the performance of the silicone sheet;

[0074] S4, cutting and trimming: cutting the vulcanized silicone sheet to obtain a thermally conductive silicone sheet of a desired size and shape, and trimming the cut silicone sheet to remove burrs and uneven parts;

[0075] S5. Finished product inspection: The cut and trimmed thermal conductive silicone sheet is subjected to a thermal conductivity test to ensure that it meets the requirements.

[0076] Specifically, in this embodiment, the stirring time in S2 is 30-40 min, the first vulcanization time in S3 is 10-30 min, the second vulcanization time is 15-20 min, and the temperature of the two vulcanizations is 150° C.-200° C.

[0077] Experiment: A Chinese patent thermal conductive silicone sheet (Announcement No. CN110517996A) was selected as comparative example 1.

[0078] A Chinese patent for a thermally conductive silicone sheet and its preparation method (Announcement No. CN115584129B) is a comparative example 2

[0079] The thermal conductivity is tested by DRL-3 thermal conductivity tester, and the testing standard is ASTMD5470; the high temperature resistance test is tested by high temperature test box, placed at 200℃ for 48 hours, and the appearance changes are observed by naked eyes; the density test method is to divide the mass of the conductive silicone sheet by its volume, and the volume can be tested by the water displacement method. The test results are shown in Table 1:

[0080] Table 1 Performance test results are as follows:

[0081] sample Thermal conductivity / W(m·K) <![CDATA[Density / g / cm 3 > Appearance changes Embodiment 1 28 3.0 No change Embodiment 2 30 3.1 No change Embodiment 3 32 3.2 No change Comparative Example 1 12 2.5 Discoloration occurs Comparative Example 2 9.4 1.8 Discoloration occurs

[0082] It can be seen from the above that the thermal conductivity of the thermally conductive silicone sheet of the present invention is at least 28W / (m·K), while the thermal conductivity of comparative examples 1 and 2 is relatively small. Therefore, compared with the existing thermally conductive silicone sheet and the thermally conductive silicone sheet of the comparative example, the thermally conductive silicone sheet of the present invention has a high thermal conductivity and can replace the existing thermally conductive silicone sheet, which is beneficial to the thermal conduction and heat transfer of the product.

[0083] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0084] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high thermal conductivity thermally conductive silicone sheet, characterized in that: The invention comprises the following raw materials in parts by weight: 90 parts of silicone rubber, 40-50 parts of thermal conductive filler, 1-5 parts of reinforcing agent, 1-3 parts of anti-aging agent, 1-3 parts of antioxidant, 2-3 parts of cross-linking agent, 3-6 parts of flame retardant and 1-2 parts of catalyst; The silicone rubber is organic silicone rubber; The thermal conductive filler is graphite and alumina, wherein the ratio of graphite to alumina is 1:

2.

2. A high thermal conductivity thermally conductive silicone sheet according to claim 1, characterized in that: The reinforcing agent comprises metal powder filler, metal oxide and inorganic non-metal, wherein the ratio of metal powder filler, metal oxide and inorganic non-metal is 1:0.8:0.7; The metal powder filler is copper powder or aluminum powder, the metal oxide is aluminum oxide or magnesium oxide, and the inorganic non-metal is graphite or silicon carbide.

3. The high thermal conductivity thermally conductive silicone sheet according to claim 1, characterized in that: The anti-aging agent is benzophenone-p-diazepine halide or butyl hydroxymethylbenzamide, and the antioxidant is tert-butyl p-toluic acid or 2,6-di-tert-butyl-4-methylphenol.

4. The high thermal conductivity thermally conductive silicone sheet according to claim 1, characterized in that: The crosslinking agent is composed of an organic silicon crosslinking agent and an inorganic silicon crosslinking agent, wherein the ratio of the organic silicon crosslinking agent to the inorganic silicon crosslinking agent is 0.4:0.

6. The organosilicon crosslinking agent is one of polydimethylsiloxane or siloxane and epoxy crosslinking agent; The inorganic silicon cross-linking agent is one of silicon dioxide, silicon trioxide or silicate.

5. The high thermal conductivity thermally conductive silicone sheet according to claim 1, characterized in that: The flame retardant is magnesium hydroxide and aluminum hydroxide, wherein the ratio of magnesium hydroxide to aluminum hydroxide is 0.6:0.

4.

6. The high thermal conductivity thermally conductive silicone sheet according to claim 1, characterized in that: The catalyst is graphene or aluminum oxide.

7. A high thermal conductivity thermally conductive silicone sheet according to any one of claims 1 to 6, characterized in that: The method for preparing the high thermal conductivity thermally conductive silicone sheet comprises the following steps: S1. Raw material preparation: First, select organic silicone with high plasticity and fluidity as the basic material, and select thermal conductive fillers, reinforcing agents, anti-aging agents, antioxidants, cross-linking agents, flame retardants and catalysts in a certain proportion; S2. Raw material stirring and degassing: Pour the prepared raw materials into the mixing drum and stir the raw materials fully through mechanical equipment. After stirring, let the mixture stand for a period of time and then perform vacuum extraction to expel the air mixed in during stirring to avoid bubbles during the molding process; S3, molding and vulcanization: S31: pouring the stirred raw materials into a molding die, and rolling them through a calender to achieve a desired thickness; S32: placing the calendered silicone sheet into a vulcanizer for high-temperature vulcanization treatment to improve physical properties; S33: vulcanizing the vulcanized silicone sheet again in a vulcanizer to further improve the performance of the silicone sheet; S4, cutting and trimming: cutting the vulcanized silicone sheet to obtain a thermally conductive silicone sheet of a desired size and shape, and trimming the cut silicone sheet to remove burrs and uneven parts; S5. Finished product inspection: The cut and trimmed thermal conductive silicone sheet is subjected to a thermal conductivity test to ensure that it meets the requirements.

8. The high thermal conductivity thermally conductive silicone sheet according to claim 7, characterized in that: The stirring time in S2 is 30-40 minutes, the first vulcanization time in S3 is 10-30 minutes, the second vulcanization time is 15-20 minutes, and the temperature of the two vulcanizations is 150°C-200°C.