Coating method is the fabric directly or indirectly by coating, so that the fabric is waterproof, breathable is generated through the microporous structure or the hydrophilic and have. It can be divided into three types: porous coating, hydrophilic coating, microporous hydrophilic binding method. The production process of the coated fabric has low cost, hydrophilic coating with water as the solvent, low cost, less pollution, hydrophilic coating can be made by traditional process. But the method of coating with organic solvent system, the solvent recovery equipment, high cost, and easy to cause environmental pollution. Fabric coating treatment, drape and flexibility becomes poor, waterproof poor durability, attachment fastness.

Waterproof fabric is a fabric impedance water molecules through the. Silicone Coated Fabric The traditional method is coating on the surface of the fabric coated with a layer of impermeable, such as polyvinyl chloride resin, polyurethane resin, to eliminate its permeability, such methods are the best method used in the past, but not to solve the problem, because the coating can not through the water vapor, it limits sporadic human sweat after evaporation, and condensation in the inner surface of the fabric, wear very uncomfortable.

Waterproof and moisture permeable surface seems to be contradictory, but the agreement from the fabric structure and processing methods can be. The molecules of water vapor in diameter is 4 * 10-4 µ m, raindrop diameter is usually 102 µ M. So as long as the diameter control pore fabric in the molecules of water vapor through water droplets and range cannot pass, can play the role of waterproof and moisture permeable. Permeability of fabrics to prevent water, depending on the size and droplet surface energy of fabric on fabric surface contact angle Q, when Q is greater than or equal to 90, the fabric of the critical surface tension of water is less than the critical surface tension, the fabric can be wetted by water. But because the fabric with a wicking (capillary effect), can prevent water infiltration, so waterproof finishing properly, so that the surface of the fabric can be lower than water, at the same time as the cohesive force of the role of water, drop a pearl shaped, so that the fabric with waterproof performance. Formed in the human body, clothing, environment of the three system of moisture transfer and heat transfer mode, there are two kinds of wet: sweating divergence (liquid phase transfer) and no sense of evaporation discharge (gas phase transfer). Human body with the environment and the activity and wearing clothes, appeared in the people around the skin of the artificial climate, the relative humidity of 50%, comfortable temperature is 32 ℃. Species, moisture permeable fabric and fabric structure and fabric finishing are closely related, when the garment inside temperature is higher than the outer fabric on both sides, there is a pressure gradient, under the influence of it, the water vapor molecules can pass through the fabric of fine channel with the outside world for heat and moisture exchange. Waterproof and moisture permeable PTFE Coated Fiberglass finishing method is using film has pores on the surface of the fabric coated with or using superfine fiber woven tightly woven fabric, thereby preventing liquid water through, and allows water vapor molecules to pass through, while maintaining the fabric has a certain air permeability and moisture (water vapor), also known as waterproof and moisture permeable the fabric waterproof and breathable finishing or waterproof and moisture permeable finishing polyester mainly has the following three kinds: waterproof fabric close type is used to change the fabric structure to achieve the purpose of waterproof and moisture permeable. This kind of fabric is waterproof and moisture permeable fabrics was the earliest successful, the mechanism is: the water vapor in the yarn gap between the simple diffusion; capillary between fiber bundles passing; diffusion in the single fiber. The compact waterproof fabric now, most of the ultra-fine polyester fiber as raw material, the fabric fibers, yarns, between between closely spaced, make the fabric without water repellent finishing conditions, the water pressure up to 104-1O5Pa. At the same time, capillary formation fiber yarn, due to the capillary effect, can very good transmission of water vapor. Compact fabric has the advantages of simple preparation process, is mainly the change of yarns and filament fineness, clothing drape made good, good moisture permeability. But the fabric water pressure is relatively low, greatly limits its scope of application. Laminated fabric is also called paste film waterproof and moisture permeable fabric, it is the functional film is pasted onto the fabric, the fabric according to the functional film used can be divided into three categories: microporous membrane type, dense hydrophilic membrane, microporous hydrophilic membrane. Adhesive here also play a very important role, there are two main types of adhesives: moisture permeable, continuous coating; not breathable, only to dot type adhesive, not to undermine the fabric moisture permeability, the most successful, the most famous is the American company W.L.Gore Gore-Tex fabric, it is currently on the market recognized the most advanced waterproof breathable fabric, it is the use of polytetrafluoroethylene (PTFE) membrane and fabric composite, due to the preparation of microporous membranes need special equipment and technology, product processing difficulty is big, cost is high, the price of your clothing, the soft soft, drape, not too satisfactory.