含气材料的可压缩性在注塑微发泡中的研究与应用

Study and application of pressure⁃volume behaviors of entrained gas materials in foam injection molding

利用改进的常规微发泡注射成型机可对预塑含气聚合物熔体产生高压而实现了注射成型的压力-体积-温度(PVT)的在线测量。通过对聚苯乙烯和聚丙烯的含气或不含气熔体在一定温度下的压力-体积(PV)行为进行研究,发现含气聚合物熔体的可压缩性远大于不含气聚合物熔体。在实际应用中,含气聚合物熔体的较大的可压缩性可用于辅助注射和加快气体融入熔体过程从而提高发泡质量。另一方面,根据含气聚合物熔体的可压缩性大而存在的安全隐患所做的压力释放试验,首次在国内提出了新的含气材料注射成型的安全操作指导。

In this study,in⁃line measurement of pressure⁃volume⁃temperature in injection molding was achieved by using a modified conventional microcellular injection molding machine that generates high pressure on the recovered entrained gas polymer melt.The studies on the pressure⁃volume behavior of entrained gas melts of polystyrene and polypropylene at a certain temperature indicated that the compressibility of entrained gas polymer melts was much greater than that of gas free polymer melts at specific temperature.In practical applications,the larger compressibility of entrained gas polymer melts can be used to assist in injection and speed up the gas integration process into the melt,thereby improving foaming quality.On the other hand,the pressure release test based on the potential safety hazards of entrained gas polymer melt due to its large compressibility of the melt has put forward a new safety operation guide for injection molding of entrained gas materials for the first time in China.