三元乙丙橡胶汽车门框密封条析出物分析与胶料配方优化

Analysis on the Migrated Substances of EPDM Car Door Seals and Formulation Optimization

分析三元乙丙橡胶(EPDM)汽车门框密封条析出物产生的原因,研究密封条胶料配方改进方案。红外光谱分析得出,析出物为加工助剂L-24和少量喷涂材料的混合物,不含聚乙二醇(PEG-4000)。加工助剂L-24用量由4份减至2份的胶料硫化特性变化不大,门尼粘度提高,物理性能和耐热老化性能变化不大,满足企业标准要求;密封条在存放和使用过程中未出现析出物。EPDM汽车门框密封条胶料加工助剂L-24用量不宜超过2份,或与润滑剂并用。

In this study, the reasons for substances migrating to the surface of EPDM car door seal were analyzed and the formulation was improved. Through FTIR analysis, main migrated substance was identified to be processing aid L-24 and the rest was small amount chemicals from coating composition. It did not contain any PEG（PEG-4000）. In the improved formulation, the addition level of L-24 was reduced from 4 phr to 2 phr. It was found that the curing characteristics of the compound changed little, the Mooney viscosity increased, and the physical properties and heat aging resistance of the vulcanizates were kept unchanged, which met the requirements of the enterprise standard. The testing results showed that no migrated substance was detected during the storage and application of the improved door seal. It was recommended to use L-24 at the addition level not exceeding 2 phr or with a lubricant.