Many people misunderstand that water-repellent fabric is also water-proof. However, water-proof textile is totally different from water-repellent one. Water-proof or water-repellent fabric, this article tells you the way to identify them.
Water repellency refers to the deposition of hydrophobic compounds on the surface of the fiber. That’s to say, there are still pores on the surface, through which air and water vapor can also pass. Generally, water droplets are formed on the cloth surface (like lotus leaves). It’s not really waterproof, but it reduces the water absorption by the fabric. As a result, the water can be “pulled away” from the surface of the fabric. But the water will still seep into the fabric after a long stay.
Water-repellent processing uses various chemical materials to attach a layer of ultra-fine “needle beds” on the surface of the fabric. So the tension on the fabric surface is less than the cohesive force of the water. And the water droplets will form water droplets and roll away instead of spreading out and soaking.
However, If this “needle bed” structure is flattened or covered with oil stains, the water repellency will be greatly reduced, and even fabrics begin to absorb water. The water repellent effect of the fabric will gradually weaken or even fail with washing and long-term use.
Therefore, if you wear water-repellent clothes in the rain, you can quickly shake off the water droplets on the surface of the clothes. But whether the clothes inside will get wet depends on the amount of rainwater and the time it stays in the rain. Water-repellent is not completely waterproof.
For fabric, there are two ways to achieve the water-proofing property, lamination, and coating.
lamination refers to a composite layer of waterproof material. and there are also various treatment forms such as capsule fibers, compact fabrics, siliconization, etc., They are usually located in the inner layer of the fabric, which is often referred to as a “waterproof membrane”. The waterproof membrane is a composite fabric that combines the membrane with other materials through the pasting process. The fabric itself is not waterproof. When wearing waterproof clothing in the rain, we will see water seeping into the clothing, just like ordinary fabric. But the inner layer of the garment is dry. Because the waterproof film is playing a role in the middle of the composite fabric.
The coating is that we apply on film on the surface of fabrics. Our polyester resin dispersion can form a film, which can bring water-proofing properties to the textile.