Waterproofing principle of waterproof and breathable film TPU

The waterproofing principle of waterproof and breathable film TPU (thermoplastic polyurethane) is mainly based on its unique microstructure and physical properties. TPU is a polymer material composed of soft segments and hard segments alternately arranged. The soft segments provide elasticity and flexibility, while the hard segments give the material strength and shape-retention capabilities. In TPU films, these hard segments form a microphase-separated structure, creating a physical barrier that prevents water molecules from passing through.

Due to this structure of TPU, it is able to prevent the penetration of liquid water while maintaining the overall breathability of the film. This breathability is due to the gaps between TPU molecular chains being large enough to allow water vapor molecules to pass through, but not large enough to allow larger water droplets to pass through. Therefore, the TPU film can effectively discharge moisture generated by the body while preventing external moisture from entering, achieving the dual functions of waterproofing and moisture permeability.

In addition, the surface of the TPU film is usually specially treated to increase the surface energy, making it difficult for water droplets to adhere when contacting the film, and instead forms water droplets rolling off, further improving the waterproof performance. This design makes the TPU film very suitable for use in outdoor sports equipment, footwear, clothing and other fields, providing users with a waterproof and breathable wearing experience.