The raw materials produced by melt polymerization are generally processed into pellets of about 2.5*2.5*3mm, commonly known as polyester chips. The chips are mainly used for the production of fibers, containers, packaging materials, films, engineering plastics, etc. However, its intrinsic viscosity is relatively low, usually only about 0.65dl/g. The production, like conveyor belts, tire cords, solar back sheet films, packing belts, etc. require a high IV polyester chip. Hubei Decon can supply high IV PET pellet (0.75dl/g and 0.92dl/g), which is used for solar back sheet film.
There are two ways to obtain high-viscosity polyester. One is to use melt viscosification (ie, liquid phase viscosification), that is, to add a post-polycondensation kettle in the polycondensation process. This method is suitable for ultra-large-scale production. The another is solid-state tackification of the regular PET chips. And there are two types, continuous and batch. A continuous solid-phase polycondensation system is suitable for large-scale modern production with PET chips as raw materials because of its high production efficiency and automatic control. A large amount of high-temperature (above 205℃) nitrogen flow is applied in the production process. Batch solid-phase polycondensation is suitable for producing small amounts and multiple varieties. The chips are run in a vacuum drum at high temperatures. Generally, the higher the viscosity, the slower the viscosity increases. So the solid phase tackification time is very long. The high IV polyester chip for industrial monofilament yarn generally reaches 1.05-1.25dl/g, and the tackification time often takes 35-60 hours.