Studies On The Preparation Of MQ Resin And Its Application In Halogen Free Flame Retardant Thermal Conducting Silicone Glue

MQ (MDQ, MTQ) silicone resin was prepared through hydrolytic condensation of tetraethoxysilane and hexamethyl disiloxane in this paper. The effect of content of the acid catalyst,the kinds and contents of co-solvent and hydrolysis reaction time on properties of MQ silicone resin was studied. Halogen free flame retardant thermal conducting silicone glue was prepared, which contained vinyl silicone oil, flame retardant and thermal conducting fillers, MQ silicone resin as the reinforcing filler. The effects of content of the MQ resin, M/Q value, vinyl content, and the MDQ, MTQ resin, flame retardant and thermal conductivity of fillers on the viscosity, tensile properties, thermal conductivity, flame retardancy and electrical properties of RTV silicone rubber were studied.The results showed that the content of the acid catalyst,the kinds and contents of co-solvent and hydrolysis reaction time had a great influence on the performance of MQ silicone resin. Gel was easy to form when the content of hydrochloric acid and solvent and hydrolysis reaction time was too small. MQ silicone resin had a goof reinforcement effect when toluene content was 0.5 in total sovent. Effect of MQ silicone resin on viscosity of RTV silicone rubber depended on M/Q value and the content of MQ silicone resin. The smaller M/Q value of MQ silicone resin, the higher the viscosity. MQ silicone resin with less M/Q ratio had higher influence on the viscosity of silicone rubber; Effect of MQ silicone resin on properties of RTV silicone rubber depended on the M / Q value, vinyl content and its contents. When M / Q value of MQ silicone resin was 0.6, vinyl content was 6.8% and its amount was 7 phr, MQ silicone resin provided the silicone rubber with proper mechanical properties. The silicone rubber had higher mechanical properties when the molar ratio of D unit in MDQ silicone resin and the molar ratio of T unit in MTQ resin were 10% and 20%; With the increase of content of MQ silicone resin in the silicone glue, the thermal conductivity of silicone rubber and its flame retardant properties would decrease. For suitable properties, the content of MQ silicone resin should be controlled in less than 10 phr. With the increase of MQ silicone resin, volume resistivity of silicone rubber increased correspondingly.