Heat-conducting silicone rubber composite material and preparation method thereof

Abstract

The invention relates to a heat-conducting silicone rubber composite material and a preparation method thereof. The heat-conducting silicone rubber composite material comprises, by weight, 20-80 parts of silicone rubber matrix, 20-80 parts of inorganic heat-conducting powder, 0.5-5 parts of silicone oil, 0.2-2 parts of cross-linking agent and 0.2-2 parts of coupling agent. The preparation method includes: 1, premixing: adding the silicone rubber matrix, the inorganic heat-conducting powder after being pretreated and auxiliaries like the cross-linking agent into a highly-mixing machine for premixing; 2, extruding and granulating: adding premixed materials into extensional rheological plasticizing and extruding equipment for extruding and granulating, wherein temperature of the extensional rheological plasticizing and extruding equipment at each stage of extrusion is 150-250 DEG C, rotating speed of a rotor is 10-150rpm, and rotating speed of a feeder is 10-100rpm. By the preparation method, the injection-molding-grade heat-conducting silicone rubber composite material which is high in heat conductivity and excellent in mechanical performance can be prepared to be widely applied in the heat-radiating field of electronic appliances, space flight and aviation and military industry.

Description

technical field [0001] The invention relates to the field of thermally conductive polymer composite materials, in particular to a high thermally conductive injection molding grade composite material and a preparation method thereof. Background technique [0002] With the development of modern electronics industry, information industry and high-tech, especially the rapid development of microelectronics integration technology, the problem of heat dissipation of devices has become increasingly important. High thermal conductivity composite materials can not only provide safe and reliable heat dissipation channels for electronic components, but also play the role of insulation, shock absorption, moisture resistance and corrosion resistance. The thermal conduction path formed by thermal conductive fillers in thermal conductive composite materials greatly affects the composite material thermal conductivity. [0003] Silicone rubber is a kind of special synthetic rubber, which is ...

AI Technical Summary

Problems solved by technology

However, the thermal conductivity of unfilled silicone rubber is very poor, and the thermal conductivity is generally only 0.165 W / (m﹐K). It can be improved by filling thermal conductive materials (aluminum trioxide, aluminum nitride, boron nitride, etc.). Some solutions to improve the thermal conductivity of silicone rubber are basically adding thermal conductive fillers to the silicone rubber matrix to achieve the purpose of improving thermal conductivity. The existing problems are: (1) The viscosity of the resin polymer used is relatively high, and the viscosity is greater after adding fillers ; (2) The filler is prone to agglomeration and settlement, and the amount of thermally conductive filler added is limited, which affects the improvement of the thermal conductivity of the obtained material; (3) To achieve the ideal thermal conductivity effect, the amount of thermally conductive material is usually greater than 70~80 wt%. This may deteriorate the mechanical properties of silicone rubber and affect the performance of other aspects; (4) the preparation process is relatively complicated, requiring multiple heating and stirring or heating vulcanization, high energy consumption, which is not conducive to energy saving and emission reduction, such as Chinese patent No. The invention patents of ZL20081146554.X and ZL102220006.X basically adopt the above steps

(5) Most of the products need to be molded by secondary molding or potting and vulcanization. The processing procedure is complicated and inconvenient to use