Study On One Component Addition Curing Thermal Insulate Silicone Rubber

With the miniaturization development of microelectronic packaging and IC, the demand of thermal conductive materials expands fastly. The thermal interface materials of silicone rubber are widely concerned due to the outstanding properties, such as aging resistance properity, high and low temperature durability, high voltage, wether resistance and electrical insulation and so on.In this paper, a high performance one component additional silicone rubber is developed, whose thermal conductivity (TC) is up to 1.08W/mK and Dielectric Breakdown Strength is above 13kV/mm. The study includes how the filler (single and mixed), methods of filler modification, catalyst and crosslinker affect the TC, shore hardness, curing temperature, shearing strength and insulation performance of this thermal silicone rubber, and it's comprehensive performance is equal to Henkel 5404.Firstly, the effect of different fillers (single and mixed) on thermal performance is studied by testing the thermal conductivity with steady flow method. It is found that the descending sequence of thermal conductivity of thermal insulate adhesive with different fillers is AlN, Al₂O₃, ZnO in same conditions. Compared with thermal insulate adhesive with single fillers, the adhesive with mixed fillers can be improved significantly and the best ratio is 4:1.Secondly, it is found in filler modification research that the thermal insulate adhesive will be demixed if the filler is modified by overall blending method. While the phenomenon is avoided by alcohol water deposition method and the different of fillers between before and after being modified are analyzed by FTIR, XRD and SEM.Thirdly, it is found that with the increase of crosslinkers, the thermal insulate adhesive of the thermal conductivity decreases, the shoreA hardness decreases, the crosslinking density decreases, the curing temperature decrease and with the increases of catalyst, the thermal insulate adhesive of thermal conductivity decreases, the shoreA hardness has no clear changing and the curing temperature decreases at same time during adjusting the amounts of crosslinker and catalyst to solving the problem of bubbles. And finalized the best dosages of them are matrix's 5%and 0.2%.At last, this paper investigates the effect of different curing temperature on the conductivity of thermal insulate adhesive. It is found that the thermal conductivity decreased and the shoreA hardness increased with the curing temperature increased. The shear strength of the thermal insulate adhesive on aluminum is higher than on copper and the shear strength significant improve after the metal materials are immersed by silane coupling agent. If add some silane coupling agent during preparation the thermal insulate adhesive, The shear strength can also be enhanced. But with the increase of silane coupling agent the shear strength decrease.