Heat-conducting silicone grease and preparation method thereof

Abstract

The invention provides heat-conducting silicone grease and a preparation method thereof. The heat-conducting silicone grease is prepared from the following components in parts by mass: 100 parts of polydimethylsiloxane, 5-20 parts of modified silicone oil, 1300-1800 parts of modified heat-conducting composite powder and 2-10 parts of a thermal gel additive. Through grading of spherical aluminum oxide with different particle sizes and by utilizing the characteristics of strong surface effect and small-size effect of nano quantum dots, cavity gaps dispersed among aluminum oxide particles are uniformly filled, so that the thermal resistance of the product is effectively reduced, the thixotropic index of the heat-conducting silicone grease is improved, and the heat-conducting silicone grease is endowed with a shear thinning characteristic; and meanwhile, the heat-conducting silicone grease has enough binding power, and the aging property of the heat-conducting silicone grease is improved.Meanwhile, the particle size distribution of the filler is strictly controlled, and the selected filler is very narrow in particle size distribution and has good monodispersity; the filler with the particle size larger than 20 microns is screened out through sieving processing, so that it is ensured that the filler grading effect is good, and gaps are avoided; and the heat-conducting silicone grease is low in thermal resistance value and excellent in aging performance.

Description

technical field [0001] The application relates to the field of thermally conductive materials, in particular to a thermally conductive silicone grease and a preparation method thereof. Background technique [0002] At present, there are many types of thermal conductive silicone grease on the market. Different physical characteristics and parameters determine different uses. For example, some are suitable for heat conduction of central processing units, some are suitable for heat conduction of power supplies, and some are suitable for heat conduction of memory sticks, etc. Due to different working conditions, different requirements are put forward for the performance of thermal conductive silicone grease. As thermal conductive silicone grease is used more and more widely, more requirements are put forward for its characteristics. Generally, thermally conductive silicone grease with thixotropy has better scraping property during use, no sag phenomenon, is conducive to glue coa...

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Problems solved by technology

[0003] However, although the thixotropic silicone grease with high thermal conductivity introduced on the market has agitation and thixotropy, it mainly achieves thickening and thixotropy by adding thixotropic agents, resulting in high thermal resistance, and although it has certain Thixotropy, due to the thickening of the system, its shear thinning characteristics are not obvious, and the viscosity drops little after shearing, resulting in poor fluidity and other deficiencies

At the same time, when the thermal conductive silicone grease is applied between the heat source and the radiator, due to the inconsistent thermal expansion coefficients of the radiator and the heat source, the heat source and the radiator will be slightly deformed after multiple cold and heat cycles during long-term use, which is easy Pumping occurs, and at the same time, the separation of silicone oil and thermal filler often occurs, the thermal grease coating becomes dry, differentiated, cracked, and the thermal conductivity deteriorates, which leads to thermal runaway due to the lack of thermal grease between the heat source and the radiator

[0004] The current thermal conductive silicone grease products still have many disadvantages, such as low thermal conductivity, large thermal resistance, poor aging resistance, easy to dry powder under high temperature and high humidity, high viscosity, poor rheology, not conducive to screen printing, etc. It cannot effectively solve the heat dissipation problem of high-power electronic components

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