1. Polyethylene. The English abbreviation of polyethylene is "PE". At the time of polymerization, polyethylene is also divided into high-pressure polyethylene and low-pressure polyethylene according to different pressures. The English abbreviations are "LDPE" and "HDPE", respectively. High-pressure polyethylene has a low crystallinity, so it has a small density and a soft texture. Compared with low-pressure polyethylene, it has higher transparency, and has superior impact resistance and low temperature resistance, but it is not heat resistant. Low pressure polyethylene is more permeable than high pressure polyethylene, but it is less impact resistant than high pressure polyethylene. Both polyethylenes are susceptible to stress and crack.
2. Polyamide. The acronym for polyamide is "PA". There are many classifications of polyamides, and the chemical structure should also be different for different synthesis, and the performance will be somewhat different, but their common points and properties are similar. Polyamide has a high crystallinity, high mechanical strength, good toughness and fatigue resistance, and it is relatively easy to color and mold, and can be used at room temperature for a long time. However, its thermal deformation temperature is low, its hygroscopicity is relatively large, and its dimensional stability is relatively poor.
3. Polyformaldehyde. POM is a highly crystalline substance and is abbreviated as "POM" in English. POM is a very elastic material. Its chemical stability, impact resistance and creep resistance are very strong, and its rigidity, strength and abrasion resistance are very high. It is a commonly used project Sexual material. However, the shrinkage rate of polyoxymethylene is high, the size control technology is very high, and the corrosion resistance is relatively low.
Influence of plastic bottle cap material on mold
1. Different plastics will have different shrinkage. When we consider processing plastic molds, we must pay attention to the shrinkage of plastic molds. Before we open the plastic mold, we must determine the shrinkage of the mold, otherwise it is easy to cause the mold to be scrapped. Especially large plastic molds.
2, plastic characteristics requirements for plastic mold steel. When we are processing plastic molds, we must first understand the type of plastic when selecting mold steel. For example, the nylon plastic we often use is corrosive. When we choose mold steel, we must consider using stainless steel mold steel. If we use highly transparent PC plastic, we have to choose mold materials with high polishing performance, such as 2738 and other materials.