Waterproof breathable fabric is a new type of textile fabric. According to the principle of moisture permeability, it can be divided into two types: molecular conductive moisture permeability and microporous moisture permeability.
Microporous moisture permeability principle: in the state of water vapor, water particles are very small, according to the principle of capillary movement, can be successfully permeated into the capillary to the other side, thus the phenomenon of vapor penetration. When water vapor condenses into water droplets, the particles become larger. Due to the surface tension of water droplets (" pulling and counteracting "between water molecules), water molecules cannot successfully break away from the water droplets and penetrate to the other side, which prevents water infiltration and makes the vapor membrane waterproof.
Moisture vapor transmission principle: molecular conductivity is in the condition of water vapor, on both sides of the membrane water vapor concentration difference exists, IPU composite cloth layer in the inside of the TPU molecular hydroxyl and carboxyl combination of high concentration of water molecules inside, and then release to the low concentration of water vapor, because the molecular conduction, by reducing the moisture concentration difference on both sides of the TPU composite material, and no gap, so you can be totally waterproof.
The development of fully waterproof breathable fabrics (TPU composite fabrics) began in the late 1970s, and the current generation 2 products are completely waterproof and windproof with good air permeability. But using this kind of fabric made of clothing is not necessarily completely waterproof, mainly because it is in the clamps or zip the ooze water, make sure that the garment completely waterproof at all clamps are wearing TPU waterproof strip, and the zipper on TPU film, into TPU waterproof zipper, this requires a lot of artificial and cost, is why such clothes again a few years ago one of the reasons for the unit price is high, but as the dosage of waterproof and moisture permeable TPU composite fabric is more and more big, so the mature of laminating process, makes the laminating process, cost reduction, material also reduced a lot, this also is this kind of clothes over the years the unit price lower.