Waterproof-breathable fabric has been of interest in the area of protective clothing and sportswear in cold weather. For these materials, the protection level against water is known to have an inverse relationship with the vapor permeability, or breathability. That is, textile material of a more open structure would show high air permeability and low water resistance, while that of a compact structure would show opposite characteristics. There could be three types of waterproof fabrics. One is impermeable fabrics that prevent all permeation of aerosols, liquids, vapors, and gases. Another is water-repellent fabrics that repel the splash of liquids and permit the permeation of gas or vapor. The other is waterproof/breathable fabrics which can prevent liquid phases and permit the permeation of gas or vapors.

For waterproof breathable clothing, both the water resistance and the vapor transmission are very important for user comfort. The water-resistant fabric with low vapor transmission would build up humidity and sweat under the garment very quickly, possibly causing hyperthermia. Hence, there is a necessity for developing a waterproof-breathable fabric that can block water while exhibiting a certain level of vapor permeability.

Due to the inverse relationship between water resistance and vapor/air permeability, the protection level against water should be compromised to attain a certain level of vapor transmission. So this paper describes the mechanism of waterproof breathable fabric, various fabrics, and its application in cold weather apparel.

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About Author:

Harun Venkatesan and V.N. Gowrishankar are students in the 4th year of B.Tech in Textile Chemistry at SSM College of Engineering.