Many Jackets use PU and TPU materials, also waterproof and moisture permeable, but they are very different from GoreTex's E-PTFE materials in actual outdoor environments.
First, the three major types of waterproof and breathable fabrics on the market today:
1. High-density fabrics: Use high-count cotton yarns and in fact ultra-fine synthetic fiber fibers to make tight fabrics with high water vapor permeability and waterproof properties after water repellent finishing. The high density is characterized by good moisture permeability, good softness and drape, but low water pressure resistance (usually less than 1 meter), high defective rate, difficulty in dyeing and finishing, and poor edge rub resistance.
2, coated fabric: can be divided into hydrophilic coating and microporous coating fabric (TU and TPU). Hydrophilic coatings coat the surface of the fabric with a hydrophilic coating, which is waterproof because it covers all the voids in the fabric. If there are hydrophilic genes on the polymer chain and their content and arrangement are appropriate, they can interact with water molecules, adsorbing water molecules on the high-humidity side by means of hydrogen bonds and other intermolecular forces, and passing the hydrophilic gene clusters on the polymer chains. Desorb on the side of low humidity. Coated fabrics are generally simple to process and are characterized by low moisture permeability and low water pressure resistance. Due to the limitations of raw materials, processes, and the method itself, the contradiction between moisture permeability, air permeability, water pressure resistance, and washability has not been solved.
3. Laminated composite fabric: The laminated composite fabric combines waterproof, moisture-permeable and wind-proof warmth, and has obvious technical advantages. It uses laminated technology to integrate ordinary fabrics with E-PTFE to complement one another, and is the main development direction of waterproof and moisture-permeable fabrics. At present, GOER-TEX of Gore Inc. and Dentik of Dengding Co., Ltd. in the US all use E-PTFE (expanded polytetrafluoroethylene microporous membrane).
Second, the difference between E-PTFE and TPU, PU:
At present, some brand-name counterfeit goods, Weihuo, and some clothes that are known to have waterproof and moisture-permeable functions on the domestic outdoor product market are labeled GOER-TEX. In fact, they mainly use PU and TPU. Only those foreign formal channel products (labeled as GOER-TEX) and domestic (labeled as DENTIK) use E-PTFE microporous membranes.
From the test data point of view, the current test standards mainly include ASTM E96 BW (7 types) in the United States and JIS 1092B (6 types) in Japan. The TPU can achieve: 5800 g/m2/day water vapor transmission and 10000 mmH2O static water pressure. This data is similar to that of E-PTFE, but this test is performed under normal temperature and static conditions. The humidity is greatly affected by temperature, humidity, and air pressure. TPU and PTFE are static at temperatures between 20 and 30 degrees. It is quite, but under dynamic conditions, the amount of exercise is large, and the sweating is increased. The TPU is limited in moisture conduction, and it is too late to absorb vomiting. At low temperatures, the lower the temperature is, the greater the difference is. As the temperature decreases, the TPU molecular activity declines and contracts. At 0°C, the TPU's moisture-transfer capacity drops exponentially. At 0°C or below, it is almost zero. Brittleness is easily broken at -15°C. If the water is poured directly above it, the temperature will be high, and the E-PTFE will be under zero temperature. There will be no change from 150 degrees to 300 degrees, no change in the ability to conduct moisture, and the ability to expel water vapor faster and keep it dry and comfortable. In addition, it has strong corrosion resistance, strong acid resistance, and strong alkali resistance. It can protect against toxic chemicals. The micropores of E-PTFE are not a straight channel, but channels form a net structure in the membrane and the wind cannot pass through directly. When the barrier is changed and the direction is changed back to achieve the windproof effect and at the same time maintain the warmth, E-PTFE is an ideal material for use in harsh environments.
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