Water repellent, abbreviated as W/R.
Water repellent refers to the deposition of hydrophobic compounds on the surface of the fiber. There are pores on the surface of the fabric. Air and water vapor can pass through. Generally, water droplets (like lotus leaves) are formed on the cloth surface. It is not really waterproof, but Reduce the absorption of water by the fabric, so that the water can be "pulled away" on the surface of the fabric, and the water will still seep into it if it stays for a long time.
Water-repellent processing uses a variety of chemical materials to attach an ultra-fine "needle bed" to the surface of the fabric to make the surface tension of the fabric less than the cohesive force of water, so water droplets will roll away instead of spreading and soaking.
Therefore, you can quickly shake off the water droplets on the surface of the clothes when you wear water-repellent clothes on rainy days, but whether the clothes inside will get wet depends on the amount of rainwater and the time spent in the rain. Splash-proof water is not really completely waterproof.
Waterproof refers to waterproof and moisture-permeable fabrics, generally refers to the rubber bottom on the bottom of the fabric, divided into coating and lamination.
Coating is often referred to as coating, and lamination refers to lamination, that is, compounding a layer of waterproof material. Most waterproof fabrics use laminated (film) materials, and there are also various treatments such as capsule fibers, compact fabrics, and siliconization, and they are usually located in the inner layer of the fabric, which is what people often call "waterproof membrane."
Water resistance is expressed by the water pressure resistance value, that is, a fixed area of tarpaulin blocks the continuously rising water pressure. When the surface sees a third drop of water, it is the water pressure resistance value of the fabric. Usually, it can reach the maximum value if it exceeds 1000mmH₂O. Basic waterproof ability.