Some processing issues about PVC
1. Question: I often hear that PVC powder has types 5, 7, and 8. Is there any difference? Answer: PVC powder can be divided into types 0-9 according to the degree of polymerization. Our more commonly used PVC powders are type 3, type 5,
Type 8. Type 3 has a polymerization degree of around 1500 and is mainly used to make films and shoes; Type 5 has a polymerization degree of around 1000 and mainly produces pipes and special shapes; Type 8 has a polymerization degree of around 700 and is mainly used for injection molding.
2. Question: How is the fluidity of your company’s PVC particles? How many melting fingers are there?
Camp: PVC particles generally do not use the expression melt index, because the melt index has a great relationship with temperature and shear, and PVC particles are not like general plastics such as PE and PP. Their processing temperature is relatively low and the processing range is relatively narrow. , and denier is more sensitive to shear force. Generally speaking, the flow of PVC hard materials is relatively poor, making its injection molding process more difficult. Injection molding of PVC soft material is relatively easy because it contains more plasticizers.
3. Question: What is the processing performance of PVC particles?
Answer: The main processing methods of the PVC particles produced by our company are molding and extrusion. PVC is an amorphous polymer with no obvious melting point and becomes plastic when heated to 120-150°C. Due to its poor thermal stability, a small amount of HCl is released at this temperature, which promotes its further decomposition. Therefore, an alkaline stabilizer must be added to neutralize the released HCL and inhibit its autocatalytic decomposition reaction. Therefore, PVC is hard Special attention should be paid to the processing temperature of mass injection plastics, which must be controlled within a relatively narrow processing range. After the process parameters are locked, normal processing can be performed. The processing difficulty of soft PVC injection plastic and PVC extrusion material is slightly lower, and most customers can solve it.