Because PVC plastic raw materials have the advantages of high transparency, good stability and good weather resistance, it is widely used in toys, daily necessities, auto parts, profiles and so on. The appearance quality requirements of these plastic products are very strict, and there should be no defects such as streaks, pores, whitening, halo, black spots, discoloration, poor gloss, etc. Therefore, in the entire injection molding process, the raw materials, equipment, and molds are very strict. and special requirements. Product design and mold design should pay attention to the following points: the product should not have sharp corners or sudden changes as much as possible, and the thickness should not change much to avoid the degradation of PVC; the mold should have a draft angle of more than 10 degrees, and reserve about 0.5% shrinkage; the mold temperature should be controlled by cooling water, so that the mold temperature can be controlled between 30 °C and 60 °C; the mold should be bright and chrome-plated to prevent corrosion; PVC is a heat-sensitive material, and its injection molding process is relatively high. The reason is that too high melting temperature or too long heating time can easily make PVC synthesized, so controlling the melting temperature is the key to injection molding PVC products.
