| 摘要 |
PURPOSE:To obtain releasing agent, from which neither oily volatile matter nor silicon dioxide powder develops even through the usage at high temperature, by a method wherein specified dimethyl polysiloxane is used as major agent. CONSTITUTION:The releasing agent concerned mainly consists of dimethyl polysiloxane, the content of dimethyl siloxane oligomer having the number of silicon atoms not more than 20 in which is 500ppm or less and the viscosity at 25 deg.C of which is 50-150,000 cSt. If the content of dimethyl siloxane oligomer in the agent exceeds 500ppm, the oligomer evaporates out of dimethyl polysiloxane, adheres to an exhaust fan or the like, turns into oily smears and further oxides by heat into silicon dioxide powder, resulting in exerting an adverse effect on electrical and electronic parts. If the viscosity at 25 deg.C of the agent is smaller than 50 cSt, the agent is volatile and consequently has insufficient release properties. If the viscosity is larger than 150,000 cSt, the viscosity is too thick for hardling convenience as a releasing agent. |
