Effects of Injection Molding Process on Shrinkage Rate of GFPP/Expandable Microspheres Foam Products
Zhang Chao, Ge Congxiao, He Zhilan
Crerax Science and Technology Co. Ltd., Shanghai 201315, China
摘要：以可膨胀微球DU260为发泡剂添加到玻璃纤维增强聚丙烯(GFPP)中，并注塑成哑铃状试样，研究塑化温度、微球添加量、注塑压力、注塑背压、螺杆转速以及保压时间等工艺参数对试样密度和收缩率的影响。结果表明，可膨胀微球的发泡能显著改善GFPP的密度和收缩率，且收缩率与微球发泡减重有很强的相关性。确定最佳注塑工艺条件为塑化温度240℃、微球添加量3份(相对于100份GFPP)、注塑压力0.9 MPa、注塑背压0.04 MPa、螺杆转速25 r/min以及保压时间5 s。相比于GFPP材料，GFPP/DU260材料注塑试样的密度降低17.13%，平均收缩率降低75.91%，收缩率标准差降低45.66%。
Abstract：The expandable microsphere DU260 was added to the glass fiber reinforced polypropylene (GFPP) as a foaming agent, and the dumbbell samples were prepared by injection molding. The effects of process parameters such as plasticizing temperature, microsphere addition amount, injection pressure, injection back pressure, screw rotation speed and holding time on the density and shrinkage rate of samples were investigated. The results show that the expandable microsphere can reduce the density and shrinkage rate of the GFPP sample, moreover, the decline of shrinkage rate has a strong correlation with the foaming weight loss of GFPP/DU260 material. The optimum process conditions for GFPP/DU260 are as follows, plasticizing temperature is 240℃, microsphere is added as 3 phr (for 100 phr GFPP), injection pressure is 0.9 MPa, injection back pressure is 0.04 MPa, screw rotation speed is 25 r/min and the holding time is 5 s. Compared with GFPP, the density of GFPP/DU260 is reduced by 17.13%, the average shrinkage rate is reduced by 75.91%, and the standard deviation of shrinkage rate is reduced by 45.66%.
Keywords：glass fiber reinforced polypropylene; expandable microsphere; injection molding process; shrinkage rate
Zhang Chao，Ge Congxiao，He Zhilan. Effects of injection molding process on shrinkage rate of GFPP/expandable microspheres foam products[J]. Engineering Plastics Application，2020，48(5)：69-73，87.