绝缘子用热硫化硅橡胶注射成型常见缺陷分析

Analysis of Common Defects in Injection Molding of HTV Silicone Rubber for Insulators

分析了绝缘子用热硫化硅橡胶在注射成型中的缺陷(如窝气、开裂、色痕),并提出了相应的改进建议。应选择挥发分质量分数小于1%,100℃下门尼黏度ML(1+4)为20~30的混炼胶,以保证其注射成型时具有好的流动性和成品率;根据产品大小、薄厚,选择合适的硫化剂以及硫化助剂,优先选择焦烧时间长、正硫化时间短的硫化体系,以确保较长的操作安全期,缩短生产周期,提高生产效率;从产品配方上讲,应严格控制材料中的水汽及低分子物质含量,通过高温以及抽真空等工艺减少挥发分的含量;可选择耐温性较好的色膏,加入炭黑时先将其做成色膏再成型;优化模具设计,改善注胶口分布,使流道圆润顺畅能极大避免成型制品的缺陷。

The defects of injection molding of HTV silicone rubber for the insulators(such as pocket gas,cracking,color marks)were analyzed,and the suggestions for the improvement were proposed.The compounds with volatile content less than 1%and Mooney viscosity ML(1+4)of 20~30 at 100℃should be selected to ensure good fluidity and high pass rate in injection molding.According to the sizes and thickness of the products,the appropriate curing agent and vulcanization additives were selected.The vulcanization systems with long t 10 and short t 90 is preferred to ensure a longer operating safety period,shorten production cycle and improve productivity.In terms of product formula,it is necessary to strictly control the content of water vapor and low molecular substances in the material,reduce the volatile content by high temperature and vacuum process.Selecting a color paste with good temperature resistance,making carbon black into a color paste before loading and molding,optimizing the mold design,and improving the distribution of the injection port to make flow channels go smooth,which can greatly avoid the defects of the products.