Generally, the sheath consists of "PU waterproof coating+heat sealing glue at the joint".
Glue-pressing is a special glue-pressing treatment, which is mainly aimed at the situation that the PU coating on garment stitches and seams is easy to be damaged and seeped. Generally, professional glue presses and glue strips are used to press glue at joints at high temperature to seal all joints to further prevent water leakage and water seepage.
★PU coating
PU coating is a kind of hydrophilic fabric, and its main component is polyurethane, which is soft, elastic and wear-resistant. A thin coating can be made, but it is impermeable to water vapor, so the air permeability is poor. Moreover, with the increase of time, the waterproof effect will become worse and the low temperature will become hard. The jacket made of this fabric is characterized by its low price.
★ Waterproof membrane E-PTFE
Waterproof membrane: The most important component of another waterproof fabric is called breathable waterproof membrane, also called microporous membrane. The pore size of microporous membrane is about one ten thousandth of a drop of water, so it can block the entry of raindrops, and at the same time it is 700 times larger than water molecules, so it does not hinder the evaporation and discharge of sweat, so it is waterproof, dry and breathable. So how to prevent wind?
Wind-proof principle: due to the disordered arrangement of microporous membrane structure, there is no wind passing through the required one-way channel in the membrane, and the wind scatters on the membrane surface and cannot pass through the labyrinth membrane structure.