脱醇型单组分陶瓷化有机硅密封胶的研制

Preparation of Dealcoholized RTV-1 Ceramic Silicone Sealant

以70 g烷氧基封端聚二甲基硅氧烷和30 g二甲基硅油为基料,甲基三乙氧基硅烷为交联剂,二月桂酸二丁基锡为催化剂,气相法二氧化硅为补强填料和触变剂,γ-缩水甘油醚氧丙基三氧基硅烷(KH 560)为增粘剂,加入2 g乙酸乙烯酯,并添加复合陶瓷化粉制得脱醇型单组分可陶瓷化防火有机硅密封胶。研究了气相法二氧化硅用量、催化剂用量、交联剂用量、复合陶瓷化粉用量、增粘剂用量和羟基清除剂种类对密封胶性能的影响。结果表明,上述组分较佳用量为气相法二氧化硅10 g、催化剂二月桂酸二丁基锡0. 75 g、甲基三乙氧基硅烷1 g、复合陶瓷化粉用量80 g、KH 560 1. 5 g,羟基清除剂采用乙酸乙烯酯,该条件下制得的有机硅密封胶的拉伸强度为2. 7 MPa,拉伸粘接强度为1. 05 MPa,破坏类型为内聚破坏,表干时间为66 min,下垂度为2 mm,瓷化后弯曲强度为7. 5 MPa,瓷化后体积略微膨胀且外观完整无缺陷,具有良好的防火隔热效果。

A dealcoholized ceramized fire-resistant silicone RTV-1 sealants was prepared by blending 70 g of alkoxy-terminated polydimethylsiloxane,30 g of dimethyl silicone oil,methyltriethoxysilane( MTES) as a cross-linking agent,dibutyltin dilaurate as catalyst,fumed silica as reinforcing filler and thixotropic agent,3-glycidoxypropyltrimethoxysilane( KH 560) as tackifier,2 g of vinyl acetate and ceramifiable powder. The effects of the amount of fumed silica,catalyst,cross-linking agent,composite ceramic powder,tackifier,and the types of hydroxyl scavenger on the properties of silicone sealants were studied. The results show that the preferred amount of the above components is 10 g of fumed silica,0.75 g of dibutyltin dilaurate,1 g of methyltriethoxysilane,80 g of composite ceramic powder,and 1.5 g of KH 560. Using vinyl acetate as the hydroxyl scavenger,the tensile strength of the silicone sealant is 2.7 MPa,and the tensile bond strength is 1.05 MPa with cohesive failure,the surface drying time is 66 min,and the drooping degree is 2 mm,the flexural strength is 7.5 MPa after porcelainification. The volume of the ceramized silicone sealant is slightly expanded and the appearance is complete and defect-free,and it has a good fire insulation.