Due to the high light transmittance of transparent plastics, the surface quality of plastic products must be strict, and there must be no markings, pores or whitening. Fog, black spots, discoloration, poor gloss and other defects, so the raw materials, equipment throughout the injection process. Molds and even product designs must pay great attention to and impose strict or even special requirements.
Secondly, because transparent plastics have high melting point and poor fluidity, in order to ensure the surface quality of the products, the process parameters such as temperature, injection pressure and injection speed are often finely adjusted, so that the plastic can be filled with the mold without generating the plastic. Internal stress causes deformation and cracking of the product.
Therefore, strict preparation is required from the preparation of raw materials, equipment and mold requirements, injection molding processes and raw material handling of products.
(1) Preparation and drying of raw materials
Since it contains any impurities in the plastic, it may affect the transparency of the product, and therefore, storage and transportation. During the feeding process, attention must be paid to the sealing to ensure that the raw materials are clean. In particular, the raw material contains moisture, which causes deterioration of the raw material after heating, so it must be dried, and when it is injected, the drying hopper must be used for the feeding. It should also be noted that during the drying process, the input air should preferably be filtered and dehumidified to ensure that the raw materials are not contaminated.