醇型透明室温硫化硅橡胶的制备

Preparation of Translucence Dealcoholized RTV Silicone Rubber

以烷氧基封端聚二甲基硅氧烷为基础聚合物、气相法白炭黑为补强填料、添加适量的硅烷偶联剂和有机锡催化剂制得醇型透明单组分室温硫化硅橡胶,并研究了其硫化后的性能。较佳配方为:黏度20 Pa·s与5 Pa·s的烷氧基封端聚二甲基硅氧烷各50份,甲基三甲氧基硅烷2份,比表面积为260 m^2/g的气相法白炭黑10份,γ-氨丙基三乙氧基硅烷0.5份,二月桂酸二丁基锡0.3份。采用此配方制得的单组分室温硫化硅橡胶的外观为透明触变膏状,邵尔A硬度40度、拉伸强度1.6 MPa、剪切强度1.4 MPa、拉断伸长率250%;将硫化7天后的硅橡胶试片置于120℃鼓风烘箱中老化1 000 h后,剪切强度为1.65 MPa;置于温度85℃、相对湿度85%的恒温恒湿试验箱老化1 000 h后,剪切强度为1.22 MPa。

A translucence dealcoholized RTV-1 silicone rubber was prepared by α, ω-alkoxy terminated polydimethylsiloxane as the basic gel, fumed silica as the filler, silane coupling agent as the tackifier, organic tin as the catalyst, and its vulcanization performance was studied. The preferred RTV-1 silicone rubber formula was that with 50 parts of alkoxy terminated polydimethylsiloxane with the viscosity of 20 Pa · s and 5 Pa · s re- spectively ,2 parts of methyhrimethoxysilane, 10 parts of fumed silica with 260 m^2/g BET surface,0. 5 parts of silane coupling agent of （3-aminopropyl） triethoxysilane, and 0.3 parts of dibutyltin dilaurate. The prepared RTV-1 silicone rubber was a composition of transparent thixotropic paste, it cured to silicone elastomeric rubber with a shore A hardness of 40, a tensile strength 1.6 MPa, a shear strength 1.4 MPa and an elongation of 250%. After aging for 1000 hrs at 120~C in the oven for 7 days, it maintained good mechanical properties with shear strength of 1.65 MPa. After aging 1000 hrs at 85℃ and 85% relative humidity,it had the shear strength of 1.22 MPa.