Talking about the Characteristics of Transparent Materials Used in Plastics and Injection Process

Due to its light weight, good toughness, and easy molding. The advantages of low cost, back in this modern industry and daily-use products, more and more use of plastic instead of glass, especially for optical instruments and packaging industry, particularly rapid development. However, due to its requirement for better transparency, wear-resistant parts should be higher, and impact resistance and toughness should be better. Here, the composition of plastics, the entire process of injection molding process, equipment. Moulds, etc., must do a lot of work to ensure that these plastics used to replace glass (hereinafter referred to as transparent plastic), the surface quality is good, so as to meet the requirements of use. The commonly used transparent plastics on the market today are polymethyl methacrylate (commonly known as acrylic or plexiglass, codenamed pmma) and polycarbonate (coded pc). Polyethylene terephthalate (codename pet), transparent nylon. As (acrylonitrile styrene copolymer), polysulfone (code psf), etc., of which we are the most contact is pmma. Pc and pet three kinds of plastic, due to limited knitting, the following three plastics as an example to discuss the characteristics of transparent plastic and injection molding process.

First, the performance of transparent plastic

Transparent plastic must first have high transparency, followed by a certain degree of strength and wear resistance, impact resistance, heat-resistant parts is better, chemical resistance should be superior, the water absorption rate should be small, only in this way can be in use, to meet the transparency The requirements remain the same for a long time. The following table lists the performance of pmma, pc, and pet.

(1) Due to the variety of species, this is just taking the average value. Actually, different varieties of data are different.

(2) Pet data (mechanical) is the stretched data.

Second, transparent plastic injection process should pay attention to common issues

Because of the high light transmittance of transparent plastics, it is bound to require strict surface quality of plastic products, and it must not have any stripes, air holes, or whitening. Fog haze, dark spots, discoloration, poor gloss and other defects, and thus raw materials and equipment throughout the injection molding process. The design of molds and even products must pay great attention to and put forward strict or even special requirements. Second, because transparent plastics are mostly of high melting point and poor flowability, in order to ensure the surface quality of products, fine adjustments are often made to the process parameters such as machine height temperature, injection pressure, injection speed, etc., so that injection molding plastics can be filled with molds, but not Internal stress can cause deformation and cracking of the product.

Below it is prepared in raw materials. For equipment and mold requirements, injection molding process and product raw material handling aspects, talk about matters that should be noted.