Key in PET Injection Moulding: "Drying" Is an Irreplaceable Component!

Key in PET Injection Moulding: "Drying" Is an Irreplaceable Component!

To ensure the processing quality and performance of PET plastic, drying is an essential step. Did you know that PET plastic is quite hygroscopic and has a relatively high moisture content? In the injection moulding industry, PET plastic is widely used in the packaging of beverages and is considered a very common material.

So why does PET plastic need drying? The reasons are simple, and there are many benefits to drying PET for processing. Firstly, dried PET can improve the surface gloss and transparency of the final products, while also enhancing flexural and tensile strength. The drying process helps to prevent internal cracks and bubbles, ensuring stable product quality. In addition, dried PET can improve its plasticizing ability, shorten the moulding cycle, and increase production efficiency.

Did you know that PET plastic is highly sensitive to moisture, especially in its molten state? It tends to undergo hydrolysis with moisture, resulting in reduced characteristic viscosity and weakened structural strength. Therefore, thorough drying is necessary before processing PET plastic.

In general, the drying time for PET plastic needs to be at least 6 hours or more to meet normal processing requirements. The recommended drying temperature is set between 170°C and 185°C.

For effective drying, a PET dryer must meet the following conditions: firstly, it must have sufficient heating capacity to heat the air up to a maximum of 185°C; secondly, the dew point should be below -25°C to prevent water vapor from recondensing on the surface of the plastic pellets; meanwhile, proper air circulation can preheat the pellets and carry away water vapor; and finally, the dryer needs to have sufficient processing capacity to ensure a drying time of at least 6 hours, allowing highly moisture-laden pellets to dry thoroughly.

If you have further inquiries or require more information about PET plastic, PET injection moulding machines, or plastic injection moulding, please feel free to contact us! As an injection moulding machine manufacturer, UNIQUE will be glad to provide you with more details.