Key points for PET sheet production
(1) The primary conditions for PET sheet production are the control of drying time and hot air dew point, and the drying effect directly determines the physical and mechanical properties and yield of the sheet. When drying, pay attention to adjusting the drying temperature and time. The drying temperature and time should not be too high or too low. If the dew point cannot be reduced, check the molecular sieve. Aging molecular sieves cannot absorb moisture from the air and cannot achieve the purpose of drying slices. Therefore, molecular sieves need to be replaced.
(2) When the melt temperature exceeds 280C, PET sheets will discolor or decompose, so the melt temperature should be adjusted below 280C.
(3) The crack gap of the head mold determines the flatness and thickness uniformity of the sheet metal. The temperature of the three rollers plays an important role in the transparency and surface finish of the sheet metal. The melt of PET should quickly avoid the temperature region with the fastest crystallization rate. The melt temperature instantly drops below the crystallization temperature, so the distance between the mold and the embossing roller is particularly important.
The main advantages of PET sheets are their exquisite appearance, good gas resistance, good protection, good toughness, and good expansion. PET sheets do not contain stabilizers and plasticizers, and do not contain harmful elements. Their prices are very good, so they are very popular among consumers. PET sheets can be recycled and reused during production, transportation, and use, therefore they have high practical value. In the production process of PET sheets, it is necessary to correctly grasp the drying process and hot air dew point according to the production process requirements, adjust the gap between rolling rollers and the subsequent unit traction speed ratio, and improve production quality.