How is the drying time for TPE thermoplastic elastomers determined?

In the injection molding process of TPE thermoplastic elastomers, drying treatment is a critical step in ensuring product quality. Whether it is injection molding, extrusion, or blow molding, if the moisture content of the material exceeds the specified limit, it can easily lead to surface defects such as bubbles and surface defects, and even cause serious issues like reduced adhesion and performance degradation. Therefore, scientifically and reasonably determining the drying time for TPE thermoplastic elastomers is a prerequisite for ensuring smooth production and product quality. So, how exactly is the drying time for TPE thermoplastic elastomers determined? Let’s take a look together with the TPE experts from Zhongsu Wang!

1. Factors influencing drying time

The drying time for TPE thermoplastic elastomers is not a fixed value but rather the result of multiple factors acting in concert. First, the material's inherent properties are the core influencing factor, as different types of TPE exhibit varying degrees of water absorption and initial moisture content. Second, external environmental conditions play a crucial role, such as the level of ambient temperature and relative humidity, which directly impact drying efficiency. Additionally, the temperature and time settings of the drying equipment are also critical variables that must be considered.

2. Conventional Drying Conditions and Recommendations

Although drying time is influenced by multiple factors, there are some universally applicable reference standards within the industry. Based on practical experience, TPE thermoplastic elastomers are typically dried using a circulating forced-air drying oven, with a recommended drying temperature range of 70–90°C. At this temperature, the generally recommended drying time is approximately 6 hours. However, this is only a general guideline, and adjustments should be made based on specific circumstances during actual operation.

3. Handling Special Cases

Not all TPE thermoplastic elastomers require prolonged drying before processing. In fact, TPE thermoplastic elastomers are typically dried during production before packaging and storage, with moisture content generally controlled below 0.5%. For TPE thermoplastic elastomers with moisture content already meeting standards, drying is unnecessary, and they can be directly processed into finished products. However, for precision products with extremely high aesthetic requirements, or in cases where the storage environment has high humidity or prolonged exposure, even if the initial moisture content is low, appropriate pre-drying is still highly recommended.

The above content regarding how to determine the drying time for TPE thermoplastic elastomers is shared here. The drying time for TPE thermoplastic elastomers is a process parameter that requires comprehensive consideration. It depends on multiple variables such as material type, initial moisture content, environmental temperature and humidity, and the set drying temperature. Manufacturers should first understand the specific characteristics of the TPE being used, then combine actual processing requirements and environmental conditions to determine the optimal drying process through testing.

In summary, under normal conditions, drying at 70–90°C for 6 hours is a reliable starting point. However, the ultimate goal is always to ensure the material achieves an ideal drying state, thereby laying a solid foundation for producing high-quality TPE products.