制备工艺对有机硅导热垫片性能影响分析

Influence Analysis of Process on Performance of Thermally Conductive Pad

以乙烯基硅油、含氢硅油、铂催化剂、扩链剂等为原料制得有机硅导热垫片,研究了混料时间、混料真空度、硫化温度对导热垫片的性能影响。结果表明:延长混料时间,物料在剪切作用下产生的热量增多,在热作用下,活性较高的扩链剂优先与乙烯基发生扩链反应,使参加交联反应的乙烯基数量减少,最终导致混炼胶黏度升高,垫片的拉断伸长率提高,硬度降低,热导率略有增加;真空度增加,体系密堆积提升,垫片硬度,热导率和拉断伸长率提高;相较于室温硫化制备的垫片,采用100℃加热硫化制备的垫片,因温度升高,扩链反应早于交联反应,故硬度降低,拉断伸长率增加。

The silicone thermal conductive pad was prepared by vinyl silicone oil,hydrogen containing silicone oil,platinum catalyst and chain extender as raw materials.The effects of mixing time,mixing vacuum and vulcanization temperature on the performance of thermal conductive pad were studied.The results show that the heat generated by shearing increases with the mixing time increasing.Under the thermal action,the chain extender with higher activity preferentially reacts with vinyl,reducing the amount of vinyl participating in cross-linking reaction,eventually lead to the increase of the viscosity of the compounds,the increase of the elongation at break of the pad,the decrease of the hardness,and the slight increase of the thermal conductivity;the vacuum degree increases and the system is dense,the hardness,thermal conductivity and elongation at break of the pad increases accordingly;compared with the pad prepared by room temperature vulcanization,the pad prepared by 100℃ heating vulcanization has lower hardness and higher elongation at break since the chain extension reaction is earlier than the crosslinking reaction due to higher temperature.