On the characteristics of transparent raw material

2022-08-08
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Talking about the characteristics of transparent raw materials commonly used in plastics and injection molding process

because plastics have light weight, good toughness and easy molding. It has the advantages of low cost. Back then, in modern industry and daily-use products, more and more plastics are used to replace glass, especially in optical instruments and packaging industry, and the development is particularly rapid. However, due to the requirements of good transparency, high wear-resistant parts and good impact toughness, the composition of plastic, the process and equipment of the whole injection molding process are also required. A lot of work must be done to ensure that these plastics used to replace glass (hereinafter referred to as transparent plastics) have good surface quality, so as to meet the requirements of use. At present, the transparent plastics commonly used in the market to add the weighed powder into the mixing chamber of the high-speed mixer are polymethylmethacrylate (commonly known as subalpine or plexiglass, code named PMMA) and polycarbonate (code named PC). Polyethylene terephthalate (PET), transparent nylon. As (acrylonitrile styrene copolymer), polysulfone (code PSF), etc. among them, PMMA is the one we contact most to improve the energy density of the battery. Due to the limited weaving width of PC and pet plastics, the following takes these three plastics as examples to discuss the special ductility and injection molding process of transparent plastics. 1、 Properties of transparent plastics

transparent plastics must first have high transparency, and then have certain strength and near abrasion resistance, impact resistance, good heat-resistant parts, excellent chemical resistance, and small water absorption. Only in this way can they meet the requirements of transparency in use and remain unchanged for a long time. The following table lists and compares the properties of PMMA, PC, and pet

(1) due to various varieties, this is only the average value, and the actual data of different varieties are different

(2) PET data (Mechanical) is the data after stretching

II. Common problems that should be paid attention to in the injection molding process of transparent plastics

due to the high light transmittance of transparent plastics, it is inevitable that the surface quality of plastic products is strictly required, and there should be no stripes, pores, and whitening. Fog halo, black spots, discoloration, poor gloss and other defects, so in the whole injection molding process, the raw materials and equipment. Mold and even product design should pay great attention to and put forward strict or even special requirements. Secondly, because most transparent plastics have high melting point and poor fluidity, in order to ensure the surface quality of products, it is often necessary to make subtle adjustments to the high temperature, injection pressure, injection speed and other process parameters of the machine, so that when injecting plastics, the mold can be filled without internal stress causing product deformation and cracking

the following is the preparation of raw materials. Talk about matters needing attention in terms of equipment and mold requirements, injection molding process and raw material treatment of products

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