挤出硅橡胶气孔的分析研究与解决方法

通过目视观察硅橡胶切面气孔情况,探讨了脱低时间、填料用量、羟基硅油用量、放置时间、生胶硫化速率、含氢硅油用量对硅橡胶气孔的影响。结果表明,未脱低的硅橡胶硫化后存在较多气孔。当胶料脱低时间超过30 min后硅橡胶中几乎不存在气孔;较佳的填料用量为480份;较佳的羟基硅油用量为28份;当放置时间不超过24 h时硅橡胶中无明显气孔;当放置时间延长到360 h时硅橡胶中存在较多气孔;选用乙烯基摩尔分数为0.16%、0.23%、0.08%的生胶进行复配较好,不建议使用乙烯基摩尔分数高于1%的生胶或单纯使用乙烯基摩尔分数为0.16%的生胶;2,4-二氯过氧化苯甲酰硫化体系中不需要添加含氢硅油。

Analysis and Solution of Pores in Extruded Silicone Rubber

By visual observing the pores in the cross-section of silicone rubber,the effects of off-volatile time,amount of filler and hydroxyl silicone oil,storage time,vulcanization rate of raw rubber and amount of hydrogen-containing silicone oil on the pores of silicone rubber were discussed.The results show that there are many pores in the silicone rubber without off volatile after vulcanization.When the off-volatile time exceeds 30 min,there are almost no pores in the silicone rubber.The optimal filler is 480 parts,the optimal hydroxy silicone oil is 28 parts.When the storage time is less than 24 h,there are no obvious pores in the silicone rubber.When the storage time is extended to 360 h,there are more pores in silicone rubber.It is better to use raw rubber with a vinyl mole fraction of 0.16%,0.23%,and 0.08%for compounding,and it is not recommended to use raw rubber with vinyl mole fraction of 1%or only use rubber with a vinyl molar fraction of 0.16%.Hydrogen-containing silicone oil is not necessary to be added in the vulcanization system of 2,4-dichlorobenzoyl peroxide.