Low-hardness high-thermal-conductivity gel sheet and preparation method thereof

Abstract

The invention discloses a low-hardness high-thermal-conductivity gel sheet and a preparation method thereof, and relates to the technical field of thermal interface materials.The preparation method comprises the steps that mixed resin is prepared, specifically, epoxy resin, acrylated epoxy bifunctional resin and acrylic resin with methyl are added into stirring equipment to be fully and evenly mixed; the preparation method comprises the following steps of: adding an anti-aging agent, an anti-oxidation auxiliary agent, a dispersing auxiliary agent and a proper amount of organic acid as a dissolving and removing agent of a lubricant on the surface of the flake silver powder, stirring at a high speed of 1000-1500 revolutions, fully dissolving and uniformly mixing the solid auxiliary agent, and then carrying out vacuum defoaming to ensure that a resin matrix does not have a large amount of foam. According to the invention, by using the antioxidant, the aging of the resin caused by oxygen and moisture in the air can be effectively prevented, the oxidation of the silver powder can be prevented, the oxidation of the silver powder can be prevented, and the like, so that the aging resistance can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal interface materials, and in particular to a low-hardness high-thermal-conductivity gel sheet and a preparation method thereof. Background Art

[0002] The requirements for high-performance electronic devices are getting higher and higher. The high packaging and high power density components of modern electronic devices inevitably lead to thermal failures. Effective heat dissipation has become a key technology that affects the life and performance of electronic devices. Thermal interface materials are the best choice to help solve the heat dissipation problem. Thermal interface materials (TIM) are widely used in electronic packaging to enhance the heat conduction between the heat source and the heat sink interface. Thermal conductive gel has become one of the increasingly popular thermal interface materials due to its excellent thermal conductivity and reliability. Thermal conductive gel sheet belongs to a material of the silicone system.

[0003] Although low-hardness and high-thermal-conductivity gel sheets can currently be used to encapsulate some electronic devices, their aging resistance performance is severely reduced after long-term use, which has a certain impact on the subsequent normal use of the electronic equipment. Summary of the invention

[0004] The present invention provides a low-hardness and high-thermal-conductivity gel sheet and a preparation method thereof. By using an antioxidant and an antioxidant, the aging of the resin by oxygen and moisture in the air can be effectively prevented, and the oxidation of silver powder can be prevented, etc., thereby improving its aging resistance. In summary, the problems in the background technology are solved.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a low-hardness and high-thermal-conductivity gel sheet comprises the following steps;

[0007] S1, preparation of mixed resin, adding epoxy resin, acrylated epoxy bifunctional resin and methyl-containing acrylic resin into a stirring device and mixing them evenly; then adding an anti-aging agent, an antioxidant, a dispersing agent and a suitable organic acid as a dissolving and removing agent for the surface lubricant of the flaky silver powder in sequence, stirring at a high speed of 1000 to 1500 rpm to fully dissolve and mix the solid additives evenly, and then vacuum degassing to ensure that there is no large amount of foam in the resin matrix;

[0008] S2, preparation of curing agent, take an appropriate amount of the mixed resin matrix tree prepared above, put the curing agent, the auxiliary curing agent and the accelerator into the stirring kettle in turn, keep the stirring speed at 30-60rpm / min to mix evenly, then grind the evenly mixed mixture through a grinder two to three times, and then grind it through a ceramic roller three-roller mill to obtain the curing agent, and test the fineness of the curing agent with a 0-100um fineness scraper. Only when the fineness is less than 50um, it can be used as a qualified curing agent matrix for use;

[0009] S3, preparation of gel, put the resin matrix mixture prepared in the above into a stirring kettle and stir evenly, then add the ground and mixed qualified curing agent matrix, keep the stirring speed at 30-60rpm / min, slowly add the formulated amount of silver powder during the stirring process, and continue to maintain the stirring speed of 30-60rpm / min for 10-20 minutes after the silver powder is added to make the silver powder and the resin matrix mixture and the curing agent matrix evenly mixed, then grind and mix the stirred silver glue semi-finished product with a three-roller mill made of ceramic roller material at a spacing of less than 30-50um, then add the gel ground by the three-roller mill into a low-speed mixing mixer and mix evenly, then package it, and then use a revolving and rotating vacuum mixer for necessary degassing.

[0010] As a further description of the above technical solution:

[0011] The roller spacing of the grinding machine is generally adjusted to less than 20 um.

[0012] As a further description of the above technical solution:

[0013] The silver powder is added in batches slowly according to the principle of adding large silver powder first and then small silver powder and adding spherical silver powder first and then flake silver powder; and during the process of adding the silver powder, the mixer must always maintain a low speed of 30-60rpm / min.

[0014] As a further description of the above technical solution:

[0015] The epoxy resin is taken in an amount of 800-1000 parts, the acrylated epoxy bifunctional resin is taken in an amount of 200-350 parts, and the methyl-containing acrylic resin is taken in an amount of 50-150 parts.

[0016] As a further description of the above technical solution:

[0017] The anti-aging agent is taken in 10-30 parts, the antioxidant auxiliary agent is taken in 8-20 parts, the dispersing auxiliary agent is taken in 15-25 parts, and the silver powder is taken in 10-20 parts.

[0018] As a further description of the above technical solution:

[0019] The curing agent is 50-150 parts, and the accelerator is 25-50 parts.

[0020] A low-hardness and high-thermal-conductivity gel sheet is obtained by curing the gel prepared in the above method.

[0021] A chip package is prepared according to a high-power chip packaging bonding method.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] In the present invention, by using antioxidants and antioxidants, the aging of the resin by oxygen and moisture in the air can be effectively prevented, and the oxidation of the silver powder can be prevented and the oxidation of the silver powder can be prevented, thereby improving its aging resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Process flow chart for gel sheet preparation. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in 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 creative work are within the scope of protection of the present invention.

[0026] Reference Figure 1 , a low-hardness and high-thermal-conductivity gel sheet and a preparation method thereof, comprising the following steps;

[0027] S1, preparation of mixed resin, adding epoxy resin, acrylated epoxy bifunctional resin and methyl-containing acrylic resin into a stirring device and mixing them evenly; then adding an anti-aging agent, an antioxidant, a dispersing agent and a suitable organic acid as a dissolving and removing agent for the surface lubricant of the flaky silver powder in sequence, stirring at a high speed of 1000 to 1500 rpm to fully dissolve and mix the solid additives evenly, and then vacuum degassing to ensure that there is no large amount of foam in the resin matrix;

[0028] S2, preparation of curing agent, take an appropriate amount of the mixed resin matrix tree prepared above, put the curing agent, the auxiliary curing agent and the accelerator into the stirring kettle in turn, keep the stirring speed at 30-60rpm / min to mix evenly, then grind the evenly mixed mixture through a grinder two to three times, and then grind it through a ceramic roller three-roller mill to obtain the curing agent, and test the fineness of the curing agent with a 0-100um fineness scraper. Only when the fineness is less than 50um, it can be used as a qualified curing agent matrix for use;

[0029] S3, the preparation of gel, the resin matrix mixture prepared in the above is put into the stirring kettle and stirred evenly, then the ground and mixed qualified curing agent matrix is ​​added, and the silicone body is added at the same time, and the stirring speed is maintained at 30-60rpm / min. During the stirring process, the silver powder in the formula is slowly added. After the silver powder is added, the stirring speed is continued to be maintained at 30-60rpm / min for 10-20 minutes to make the silver powder and the resin matrix mixture and the curing agent matrix mixed evenly. Next, the stirred silver glue semi-finished product is ground and mixed with a three-roller mill made of ceramic roller material at a spacing of less than 30-50um. Next, the gel ground by the three-roller mill is added to a low-speed mixing mixer and mixed evenly, and then packaged, and then used. Use a revolving and rotating vacuum mixer for necessary degassing. The roller spacing of the three-roller machine should not be too small or too wide. If it is too small, some silver powder will be crushed easily, thus destroying the silver powder and silver packaging and affecting the conductive performance. If it is too large, a small amount of agglomerated silver powder cannot be effectively dispersed. Not only does it affect the utilization efficiency of the silver powder, but the agglomerated silver powder may also clog the dispensing needle or screen during the dispensing process due to the large agglomeration particles, thus affecting the performance of the silver glue. Since the thermal conductive gel sheet belongs to a type of silicone system, the thermal conductive gel sheet, also known as thermal conductive gel, heat sink gel, etc., is a gel-like silicone-based thermal conductive material, which is made of silicone resin, cross-linking agent, thermal conductive filler, etc. through stirring, mixing, encapsulation and curing, and has two forms: single-component and two-component.

[0030] Furthermore, the roller spacing of the grinder is generally adjusted to less than 20 um, and the grinder can be a three-roll grinder.

[0031] Furthermore, the silver powder is required to be added in batches slowly according to the principle of adding large-particle silver powder first and then small-particle silver powder and adding spherical silver powder first and then flake silver powder; and during the process of adding the silver powder, the mixer must always maintain a low-speed stirring of 30-60rpm / min.

[0032] Furthermore, 800-1000 parts of the epoxy resin, 200-350 parts of the acrylated epoxy bifunctional resin, and 50-150 parts of the methyl acrylic resin are taken. The epoxy resin is bisphenol F type epoxy resin, which has good heat resistance and adhesion properties and relatively high viscosity. The acrylic resin has low viscosity, good heat resistance, and good adhesion to the substrate.

[0033] Furthermore, the anti-aging agent is taken in 10-30 parts, the antioxidant is taken in 8-20 parts, the dispersing agent is taken in 15-25 parts, and the silver powder is taken in 10-20 parts. The antioxidant can select some suitable quinone-containing antioxidants to have a very good antioxidant effect. The dispersing agent is to facilitate the dispersion of the silver powder in the resin system to avoid uneven dispersion, which affects the efficiency of the silver powder, and also increases the volume and resistivity, etc. The dispersing agent can select a silane coupling agent.

[0034] Furthermore, the curing agent is 50-150 parts, and the accelerator is 25-50 parts.

[0035] A low-hardness and high-thermal-conductivity gel sheet is obtained by curing the gel prepared in the above method.

[0036] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a low-hardness and high-thermal-conductivity gel sheet, characterized in that: The method comprises the following steps: S1, preparation of mixed resin, adding epoxy resin, acrylated epoxy bifunctional resin and methyl-containing acrylic resin into a stirring device and mixing them evenly; then adding an anti-aging agent, an antioxidant, a dispersing agent and a suitable organic acid as a dissolving and removing agent for the surface lubricant of the flaky silver powder in sequence, stirring at a high speed of 1000 to 1500 rpm to fully dissolve and mix the solid additives evenly, and then vacuum degassing to ensure that there is no large amount of foam in the resin matrix; S2, preparation of curing agent, take an appropriate amount of the mixed resin matrix tree prepared above, put the curing agent, the auxiliary curing agent and the accelerator into the stirring kettle in turn, keep the stirring speed at 30-60rpm / min to mix evenly, then grind the evenly mixed mixture through a grinder two to three times, and then grind it through a ceramic roller three-roller mill to obtain the curing agent, and test the fineness of the curing agent with a 0-100um fineness scraper. Only when the fineness is less than 50um, it can be used as a qualified curing agent matrix for use; S3, preparation of gel, put the resin matrix mixture prepared in the above into a stirring kettle and stir evenly, then add the ground and mixed qualified curing agent matrix, keep the stirring speed at 30-60rpm / min, slowly add the formulated amount of silver powder during the stirring process, and continue to maintain the stirring speed of 30-60rpm / min for 10-20 minutes after the silver powder is added to make the silver powder and the resin matrix mixture and the curing agent matrix evenly mixed, then grind and mix the stirred silver glue semi-finished product with a three-roller mill made of ceramic roller material at a spacing of less than 30-50um, then add the gel ground by the three-roller mill into a low-speed mixing mixer and mix evenly, then package it, and then use a revolving and rotating vacuum mixer for necessary degassing.

2. The method for preparing a low-hardness and high-thermal-conductivity gel sheet according to claim 1, characterized in that: The roller spacing of the grinding machine is generally adjusted to less than 20 um.

3. The method for preparing a low-hardness and high-thermal-conductivity gel sheet according to claim 1, characterized in that: The silver powder is added in batches slowly according to the principle of adding large silver powder first and then small silver powder and adding spherical silver powder first and then flake silver powder; and during the process of adding the silver powder, the mixer must always maintain a low speed of 30-60rpm / min.

4. The method for preparing a low-hardness and high-thermal-conductivity gel sheet according to claim 1, characterized in that: The epoxy resin is taken in an amount of 800-1000 parts, the acrylated epoxy bifunctional resin is taken in an amount of 200-350 parts, and the methyl-containing acrylic resin is taken in an amount of 50-150 parts.

5. The method for preparing a low-hardness and high-thermal-conductivity gel sheet according to claim 1, characterized in that: The anti-aging agent is taken in 10-30 parts, the antioxidant auxiliary agent is taken in 8-20 parts, the dispersing auxiliary agent is taken in 15-25 parts, and the silver powder is taken in 10-20 parts.

6. The method for preparing a low-hardness and high-thermal-conductivity gel sheet according to claim 1, characterized in that: The curing agent is 50-150 parts, and the accelerator is 25-50 parts.

7. A low-hardness and high-thermal-conductivity gel sheet, characterized in that: The gel prepared in right 1 can be cured to obtain a low hardness and high thermal conductivity gel sheet.

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