What is the difference between water repellent and waterproof of fabrics

Many people have the misunderstanding that the water-repellent function of the fabric is waterproof. After using it, it is discovered that the fabric will seep after a long time underwater, and it is not really waterproof. In fact, "splash-proof" and "waterproof" are two different things, let's briefly describe the difference between the two.

Water repellent
Water repellent, also known as water repellent, is water repellent in English, 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, and air and water vapor can pass through. Generally, water droplets (like lotus leaves) will form on the surface of the fabric. It is not really waterproof, but Reduce the adsorption of water by the fabric, so that the water can be "pushed away" on the surface of the fabric, and the water will still seep into it after a long time.

Water-repellent processing uses various chemical materials to attach a layer of ultra-fine "needle beds" on the surface of the fabric, so that the tension on the surface of the fabric is less than the cohesive force of water, so that after the water drops, it will form water droplets and roll away instead of spreading and soaking.

If this layer of "needle bed" structure is flattened or covered with oil, the water repellency of the fabric will be greatly reduced, and it will even start to absorb water. The water-repellent effect of the fabric will gradually weaken with washing and long-term use, or even become invalid.

water proof
The English word for waterproof is water proof, which refers to waterproof and moisture-permeable fabrics. Generally, it refers to making rubber soles on the bottom of the fabrics, which are divided into two types: coating and lamination. Coating is often referred to as coating, and lamination refers to lamination, that is, compounding a layer of waterproof material. The vast majority of waterproof fabrics use laminated (film) materials, and there are also various treatments such as capsule fibers, compact fabrics, and siliconization, and are usually located in the inner layer of the fabric, which is often called a "waterproof membrane".

The waterproof membrane is a kind of composite fabric that combines the membrane with other materials and fabrics through the pasting process. The fabric itself is not waterproof, so when we wear waterproof clothing and encounter water, we will see water seeping into the clothing, just like ordinary The clothing of the fabric is the same, but the inner layer of the clothing is dry, which is where the waterproof film in the middle of the composite fabric plays a role.

The functional distinction between the two
1. Waterproof products are more durable than water-repellent products, and their physical and chemical properties are more stable.
2. Waterproof products usually will not fail due to washing and long-term use.
3. Waterproof products have a higher water pressure resistance index than water-repellent products, usually at least 3000mmH2O.
4. In the specific application of clothing, the main function of water repellent treatment is to reduce the adsorption of water on the fabric, so that water can be "pushed away" on the surface of the fabric; waterproof treatment is a completely impermeable barrier, regardless of whether the fabric absorbs water or not , it keeps water out.