Water Repellency Principle Of Non Woven Fabric Waterproof

1. What is non woven fabric waterproof

With the rapid economic development today and in the future, people's living standards have been continuously improved, and the nonwovens industry has also developed rapidly. Because it can have superior properties different from traditional textiles, nonwovens are widely used in various fields. Among them, non woven fabric waterproof has also been widely used. This article briefly introduces the water repelling principle of non woven fabric waterproof.

2. Water-repellent finishing

The water-repellent finishing of non-woven fabrics is mainly to use low surface tension finishing agents to make the surface tension of non-woven fabrics far lower than that of water, so that the surface of non-woven fabrics has a water-repellent effect, and non-woven fabrics can Maintaining good breathability, this finish is called breathable waterproof finish.

Relationship with surface energy When water droplets drop on a solid surface, the following situations may occur, as shown in the figure below: one situation is that the water droplets spread completely on the solid surface, and the second situation is that the water droplets form small droplets . The contact angle formed by the tangential direction of the solid surface and the edge of the droplet may appear in the following states. It can be seen from the figure that when the contact angle is greater than 90°, it can be breathable and water permeable.

3. Relationship between water repellency and surface roughness

The acquisition of water repellency mainly depends on the following two aspects: one is the size of the surface energy of the object; the other is the structure and state of the surface of the object to be treated.

Wenzel pointed out that if the roughness factor f is defined as the ratio of the real surface area to the apparent geometric area between the solid and liquid interface. The larger f is, the rougher the surface area is. Through calculation, it can be seen that the rough surface area can increase the contact angle, that is, the increase of f is beneficial to improve the water repellency of plants.