WHAT IS WATER REPELLENT AND WATERPROOF?
My clothes are obviously waterproof, how is it still wet? Waterproof and water repellent, can you really distinguish between them? There is a university question.
Perhaps you have had such an experience: I walked in the rain with my own water-repellent function, and I felt more and more wrong when I walked. My clothes are obviously waterproof. How is it still wet?
In fact, "water repellent" and "waterproof" are two different things. What is the difference between the two?
Water repellent, also known as water repellent, English is water repellent, abbreviated as W/R. Water repellent refers to the deposition of hydrophobic compounds on the surface of the fiber. The surface of the fabric is left with pores. The air and moisture can also pass through. Generally, water droplets are formed on the surface of the fabric (like the lotus leaf). Reducing the adsorption of water by the fabric, so that the water can be "pushed" on the surface of the fabric, and the water will stay in it for a long time.
Water repellent processing uses a variety of chemical materials to attach a layer of ultra-fine "needle bed" on the surface of the fabric, so that the tension on the surface of the fabric is less than the cohesive force of the water. Therefore, the water droplets will form a water droplet to roll away instead of spreading out. If this layer of "needle bed" structure is flattened or covered with oil, the water repellent capacity of the fabric will be greatly reduced, and even begin to absorb water. The water repellent effect of the fabric will gradually weaken or even fail with washing and long-term use.
Therefore, when you wear the water-repellent clothes on the rainy day, you can quickly shake off the water drops on the surface of the clothes, but whether the clothes inside will be wet depends on the amount of rain and the time spent in the rain. The splash-proof water is not really completely waterproof. .
Waterproof English is water resistant/water proof, which refers to waterproof and moisture permeable fabrics, generally refers to the bottom of the fabric as a rubber sole, divided into coating and lamination. Coating is a commonly used coating, and lamination refers to lamination, that is, a composite layer of waterproof material. Most waterproof fabrics use laminated (film) materials, as well as capsule fibers, compact fabrics, silicidation and other treatments, and are usually located in the inner layer of the fabric, which is often referred to as "waterproof membrane".
Waterproof film is a composite fabric that combines film with other material fabrics through the pasting process. The fabric itself is not waterproof. Therefore, when we wear waterproof clothing and encounter the rainy weather, we will see water seeping into the clothing, just like ordinary The fabric is the same as the clothing, but the inner layer of the garment is dry, which is the waterproof film in the middle of the composite fabric.
The waterproof capacity is expressed by the water pressure resistance value, that is, the water pressure of the fixed area is blocked by the tarpaulin with a fixed area, and the water pressure resistance value of the fabric is obtained when the surface oozes the third drop of water, which is usually more than 1000 mmH2O. The most basic waterproof ability.