Transparent PVC pipe is made by adding a large amount of plasticizer, a certain amount of stabilizer and other additives to PVC resin, and then extruded to form. It is widely used in construction, chemical industry, home use, for water and fluid transportation, conveying corrosive media, as well as wire casing and insulation layer. The formula of transparent PVC clear hard plastic tube mainly includes PVC resin, heat stabilizer, lubricant, plasticizer and coloring agent. Based on the above technical indicators analysis, the formula design should meet the requirements of transparency, moderate hardness, and high strength.
Accurately weigh various raw materials and put them into the kneading machine in a certain order. The feeding sequence is: PVC resin, plasticizer, stabilizer, lubricant. When the temperature reaches 100~110℃, it can be discharged.
The temperature should be controlled well in this process. The highest temperature of the material should be controlled at a level higher than the melting temperature of the material and lower than the extrusion temperature of the transparent tube pvc, that is, between 155~160℃. The purpose of granulating transparent pipe fittings is to achieve full mixing and preliminary plasticization.
The temperature of extrusion molding should be slightly higher. Generally, the transparency of the pipe is related to the molding temperature. Within a certain temperature range, the higher the temperature, the better the transparency, and vice versa. At the same time, the traction speed and cooling speed will also affect the transparency of the pipe. The traction speed of transparent PVC pipe fittings is slightly faster, and the cooling speed is faster, so the transparency of the pipe is better. The traction speed is generally 10%~15% faster than the extrusion speed, and the cooling of the transparent hose is first sprayed with cold water at the head mouth of the machine and then cooled in a water tank.
When directly extruding powder into shape, the extrusion temperature of the extruder is about 5℃ lower than that of granules. When cooling and shaping larger diameter pipe blanks, compressed air must be blown into transparent PVC pipe fittings to ensure the accuracy and stability of the pipe diameter. Note that the compressed air pressure should be stable. Pay attention to the smoothness of the traction speed to avoid changes in pipe diameter or wall thickness due to unstable traction. When stopping for a long time, it must be disassembled and cleaned to avoid decomposition problems.