For applications involving waterproof yet breathable fabrics, medical consumables, and inflatable products, many customers have already replaced polyester-TPU composites with polyether-based systems, primarily driven by the requirement for hydrolysis resistance during prolonged use under humid and hot conditions.
The ester bonds in polyester-based TPU segments are highly susceptible to degradation by water vapor under high temperature and high humidity conditions; this can lead to gradual surface tackiness and a steady decline in tensile strength, resulting in complete performance failure after several months of storage or service. In contrast, polyether-based TPU relies on a more stable ether bond structure, granting it significantly superior hydrolysis resistance; however, this comes at the cost of slightly reduced tensile strength and oil resistance.
For applications in apparel, outdoor gear, and medical devices, priority is given to long-term repeated use while maintaining flexibility and resilience, rather than solely pursuing extreme strength. This has transformed polyether TPU from a niche solution into a popular choice across the industry-particularly for orders requiring extended storage periods or shipment to tropical, humid regions.
However, do not assume that the presence of polyether alone guarantees hydrolysis resistance, as the molecule still contains urethane bonds that are prone to hydrolysis. Factors such as the additive dosage, catalyst residue levels, and whether proper drying was performed prior to production can lead to significant variations in actual durability. Currently, procurement requirements increasingly mandate the provision of strength retention data obtained from accelerated hydrolysis tests, rather than relying solely on verbal claims such as "hydrolysis resistance."
Additionally, the production phase cannot be overlooked: TPU is highly susceptible to moisture absorption; if the drying process is inadequately performed, hydrolysis may already commence during the extrusion process, with many potential risks only becoming apparent after the products are shipped. For film manufacturers, implementing effective hopper dehumidification and strictly adhering to drying protocols is as essential as formulation development.
