Waterproof and breathable fabric
Jul 30, 2019
Definition of waterproof and breathable fabric:
Waterproof and breathable fabric, it sounds like a contradiction. Since it is waterproof fabric, it is sealed. We all know that water is pervasive, so how can it be breathable? In fact, this is related to the characteristics of water. Everyone knows that the surface of water is tensioned. It can be found in life that when we pour water, water can often rise above the cup a little bit and will not flow out. This is the surface tension of water. As a result, this phenomenon is mainly because water molecules only have relatively large molecular gravitational forces, so that each water molecule is as close as possible without being separated, and water vapor is also a water molecule, but between each water molecule at this time It is completely independent and therefore not so closely linked. Using this property, the laboratory found through testing that if the pores are small enough, then it is completely possible to pass only the water in the vapor state without passing the liquid water. Using this characteristic, a waterproof and breathable material was invented by using a polyester fiber material to form a plurality of minute holes in the fabric. The most common waterproof and breathable material GORE-TEX is exemplified. There are hundreds of millions of small holes in the square inch. Each hole has a diameter of one-twentieth of the smallest liquid droplet, but 700 times larger than the minimum state of water vapor. This is the principle of waterproof and breathable fabric.
Waterproof and breathable fabric is a new type of textile fabric. Its composition is made of polymer waterproof and breathable material (PTFE film or TPU film) plus fabric composite fabric. The main functions of waterproof and breathable fabrics are: waterproof, moisture permeable, breathable, insulated, windproof and warm. From the production process, the technical requirements of waterproof and breathable fabrics are much higher than those of ordinary waterproof fabrics. At the same time, from the perspective of quality, waterproof and breathable fabrics also have functional features not available in other waterproof fabrics. The waterproof and breathable fabric enhances the airtightness and watertightness of the fabric, and its unique steam permeability can quickly discharge the water vapor inside the structure, avoiding the structure of mold and mold, and keeping the body always dry, perfectly solving the ventilation and windproof, waterproof, The problem of keeping warm is a new type of fabric that is healthy and environmentally friendly.
The waterproof and breathable composite fabric is English: Waterproofbreathablecompositefabric;
The working principle of waterproof and breathable fabric:
In the state of water vapor, the water particles are very small, and according to the principle of capillary movement, the capillary can be smoothly infiltrated to the other side, thereby causing vapor permeability. When the water vapor condenses into water droplets, the particles become larger. Due to the surface tension of the water droplets (water molecules collide with each other), the water molecules cannot smoothly escape from the water droplets and penetrate into the other side, which is to prevent The penetration of water occurs so that the vapor permeable membrane has a waterproof function.
Note that there are two kinds of waterproof and breathable fabrics: water-resistant and waterproof. The former is divided into fiber/cloth type (not windproof but good air permeability) and transparent type (windproof but poor air permeability); the latter is generally transparent. Type, two or three layers, windproof, two layers are softer than three layers, and the gas permeability is good, and the three layers are relatively strong. Water-resistant or highlywaterrepellent fabrics can seep when there is pressure on them, such as when you wear pants with this material on a wet stool.
The development of fully waterproof and breathable fabrics began in the late 1970s, and now the 2nd generation is completely waterproof and windproof and maintains good breathability. However, the garment made of this kind of fabric is not necessarily completely waterproof, mainly because it is water seepage at the seam or zipper. To ensure that the garment is completely waterproof, it is necessary to press the glue at all the seams (good waterproofing bead for good garments). This requires a lot of labor and cost, and is one of the reasons why such clothes are expensive.
