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CN-122012016-A - Bi-component organic silica gel and preparation method and application thereof

CN122012016ACN 122012016 ACN122012016 ACN 122012016ACN-122012016-A

Abstract

The invention discloses a bi-component organic silica gel and a preparation method and application thereof, wherein the bi-component organic silica gel comprises an A component and a B component, the A component and the B component comprise modified hollow glass beads, the modified hollow glass beads are obtained by modifying hollow glass beads by a modifier, and the modifier comprises trimethoxy mono-end-capped polydimethylsiloxane. The invention adopts the specific modifier to modify the hollow glass beads, improves the dispersion stability of the beads in the matrix, prevents the beads from floating or sinking in the curing process, enhances the interface bonding strength between the beads and the matrix, and obviously improves the thermal expansion behavior of the material while maintaining the integral mechanical property, the heat conduction capability and the mass density of the material.

Inventors

  • Cai Shuidong
  • LIU BIN
  • ZHAO JINGGAN
  • ZHANG YINHUA

Assignees

  • 广州回天新材料有限公司

Dates

Publication Date
20260512
Application Date
20260105

Claims (10)

  1. 1. The double-component organic silica gel is characterized by comprising a component A and a component B, wherein the component A comprises double-end ethylene polysiloxane, aluminum oxide, a silane coupling agent, a catalyst and modified hollow glass beads, the component B comprises double-end ethylene polysiloxane, terminal hydrogen polysiloxane, side hydrogen polysiloxane, aluminum oxide, a silane coupling agent, an inhibitor and modified hollow glass beads, the modified hollow glass beads are obtained by modifying hollow glass beads by a modifier, and the modifier comprises trimethoxy single-end-capped polydimethylsiloxane.
  2. 2. The two-component organic silica gel according to claim 1, wherein the mass ratio of the hollow glass beads to the trimethoxy mono-terminated polydimethylsiloxane is 1 (0.05-0.3); and/or the modifier further comprises trimethyl end-capped polydimethylsiloxane, wherein the mass ratio of the hollow glass beads to the trimethyl end-capped polydimethylsiloxane is 1 (1-3); And/or the content of the modified hollow glass beads in the component A is 1-10wt%; and/or the content of the modified hollow glass microspheres in the component B is 1-10wt%.
  3. 3. The two-component organic silica gel according to claim 1, wherein the hollow glass beads have a particle size of 20-70 μm; and/or the true density of the hollow glass beads is 0.15-1 g/cm 3 .
  4. 4. The two-component organic silica gel according to claim 1, wherein the modified hollow glass beads are prepared by a method comprising the steps of mixing the modifier with the hollow glass beads, and performing heat treatment to obtain the modified hollow glass beads, wherein the temperature of the heat treatment is 100-150 ℃.
  5. 5. The two-component silicone gum according to claim 1, wherein the two-terminal ethylene polysiloxane has a viscosity of 50-500 mpa-s at 25 ℃; And/or the vinyl content of the double-end ethylene polysiloxane is 0.4-2wt%; And/or the viscosity of the hydrogen-containing polysiloxane at 25 ℃ is 10-1000 mPa.s; And/or the hydrogen content of the terminal hydrogen-containing polysiloxane is 0.01-0.18wt%; And/or the viscosity of the side hydrogen-containing polysiloxane at 25 ℃ is 20-200 mPa.s; and/or the hydrogen content of the side hydrogen-containing polysiloxane is 0.08-0.3 wt%; And/or the silane coupling agent is trimethoxy mono-terminated polydimethylsiloxane, triethoxy mono-terminated polydimethylsiloxane or a combination thereof; And/or the particle size of the alumina is 1-70 mu m; And/or the catalyst is a platinum catalyst, wherein the platinum catalyst comprises at least one of a divinyl tetramethyl disiloxane platinum complex, a divinyl octamethyl tetrasiloxane platinum complex or a chloroplatinic acid alcohol solution; and/or the inhibitor comprises at least one of acetylene cyclohexanol, methylbutynol, tetramethyl divinyl disiloxane or trimethyl-dodecyl alkynol.
  6. 6. The two-component silicone gel according to claim 1, wherein the alumina comprises alumina a having a particle size of greater than 30 μm and less than or equal to 70 μm, alumina B having a particle size of greater than 4 μm and less than or equal to 30 μm, and alumina C having a particle size of greater than or equal to 1 μm and less than or equal to 4 μm.
  7. 7. The two-component organic silica gel according to claim 1, wherein the component A comprises, by mass, 100-200 parts of double-end ethylene polysiloxane, 600-1000 parts of aluminum oxide, 10-30 parts of silane coupling agent, 2-6 parts of catalyst and 10-120 parts of modified hollow glass microspheres, the component B comprises, by mass, 60-100 parts of double-end ethylene polysiloxane, 60-80 parts of terminal hydrogen polysiloxane, 5-15 parts of side hydrogen polysiloxane, 600-1000 parts of aluminum oxide, 10-30 parts of silane coupling agent, 1-5 parts of inhibitor and 10-120 parts of modified hollow glass microspheres, and the mass ratio of the component A to the component B is 1 (0.5-1.5).
  8. 8. A method for preparing the bi-component organic silica gel according to any one of claims 1 to 7, which is characterized by comprising the steps of mixing the bi-terminal ethylene polysiloxane in the component A with a silane coupling agent, adding aluminum oxide, performing heat treatment at 80 to 120 ℃, cooling to below 45 ℃, adding the rest of the components, mixing the bi-terminal ethylene polysiloxane in the component B with aluminum oxide, performing heat treatment at 80 to 120 ℃, cooling to below 45 ℃, and adding the rest of the components, and mixing to obtain the component B.
  9. 9. The organic silica gel material is characterized in that the organic silica gel material is obtained by mixing and curing the two-component organic silica gel according to any one of claims 1-7, the hardness of the organic silica gel material is 28-35 HA, the density of the organic silica gel material is 1.5-2.4 g/cm 3 , the heat conductivity coefficient of the organic silica gel material is 0.8-1.5W/m.K, the linear expansion coefficient of the organic silica gel material is 150-220 mu m/(m.DEG C), and the viscosity of a sample after the two-component organic silica gel material is mixed is 3000-4500 m Pa.s at 25 ℃.
  10. 10. Use of the two-component silicone gel according to any one of claims 1 to 7 in electronic packaging.

Description

Bi-component organic silica gel and preparation method and application thereof Technical Field The invention belongs to the technical field of adhesives, and particularly relates to a bi-component organic silica gel, and a preparation method and application thereof. Background The organic silicon pouring sealant is widely applied to encapsulation protection of electronic components due to excellent high and low temperature resistance, electrical insulation and flexibility, and particularly in the fields of power modules, inverters, vehicle-mounted electronics and the like which need long-term stable operation. However, conventional silicone potting adhesives generally have a high Coefficient of Thermal Expansion (CTE) (> 200ppm/°c), which is prone to the following problems under severe temperature changes (high and low temperature impact) or long term heat aging conditions: Firstly, stress damage to components on a PCB (printed circuit board) is caused by mismatching of thermal expansion coefficients of silica gel and materials such as the PCB, magnetic elements (such as inductors and magnetic cores of transformers) and the like in a high-low temperature cycle (such as-40 ℃ to 150 ℃), so that the colloid repeatedly contracts/expands, and periodic mechanical stress is applied to the components. Long-term operation can cause core cracking, solder joint fatigue, and even device failure. The magnetic element (such as ferrite) has high brittleness and is sensitive to tensile stress, and the high CTE silica gel can shrink and pull the magnetic core when the temperature is reduced, so that the damage risk of the magnetic element is increased; And secondly, the problem of volume expansion in the sealed package is that when the sealed container (such as a power module with a metal shell) is filled and sealed, the volume of the silica gel expands after being heated (the CTE of the silica gel is greatly different from that of the metal), but the silica gel cannot be freely stretched due to the limitation of the shell, so that stress is accumulated in the colloid. After long-term heat aging, the colloid may locally bulge (bulge) and even separate from the heating element (such as a power chip), so that an air gap is formed, and the heat dissipation efficiency is remarkably reduced. In the prior art, the CTE is mainly reduced by adding filler (such as alumina and silica micropowder), but the high filling amount can lead to the increase of the density of silica gel, so that the increase of the gel consumption is caused, the use cost of customers is increased, the light weight of products is affected, and the other method for reducing the CTE is to increase the crosslinking density of the silica gel, and the corresponding increase of the colloid hardness along with the increase of the crosslinking density, so that the material loses the capability of buffering vibration impact and the stress on brittle elements is increased. Disclosure of Invention In order to overcome at least one of the problems of the prior art, it is an object of the present invention to provide a two-component silicone gel, which can obtain a material with high thermal conductivity, low density and low thermal expansion coefficient by adding specific modified hollow glass beads. The second purpose of the invention is to provide a preparation method of the bi-component organic silica gel. The invention further aims to provide an organic silica gel material. The invention aims at providing an application of the two-component organic silica gel. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the invention provides a bi-component organic silica gel, which comprises a component A and a component B, wherein the component A comprises double-end ethylene polysiloxane, aluminum oxide, a silane coupling agent, a catalyst and modified hollow glass beads, the component B comprises double-end ethylene polysiloxane, terminal hydrogen polysiloxane, side hydrogen polysiloxane, aluminum oxide, a silane coupling agent, an inhibitor and modified hollow glass beads, the modified hollow glass beads are obtained by modifying hollow glass beads by a modifying agent, and the modifying agent comprises trimethoxy single-end-capped polydimethylsiloxane. On the premise of ensuring that the original hardness, density and heat conduction performance of the bi-component organic silica gel are basically unchanged, the invention realizes effective regulation and control of the Coefficient of Thermal Expansion (CTE) of the material by introducing the hollow glass microspheres. The traditional method usually needs to sacrifice other key performances when the CTE is reduced, but the innovation of the invention is that the modified hollow glass microsphere with specific structural characteristics is adopted for compound modification, so that the thermal expansion behavior of the material is obviously improved while the whole mechanica