Introduction to waterproof and breathable fabric testing
Introduction to waterproof and breathable fabric testing
Waterproof and breathable fabric is a new type of textile fabric, which is composed of polymer waterproof and breathable material (PTFE membrane) and fabric. It is made into two-layer composite and three-layer composite according to different product requirements. It is widely used in outdoor clothing, mountaineering clothing, windbreakers, raincoats, shoes, hats and gloves, cold-proof jackets, sporting goods, medical equipment, etc., and is gradually used in fashion clothing.
Working principle
In the state of water vapor, the water particles are very small. According to the principle of capillary movement, they can smoothly penetrate into the capillary tube to the other side, thus causing vapor permeability. When water vapor condenses into water droplets, the particles become larger. Due to the surface tension of the water droplets (the water molecules “pull and compete” with each other), the water molecules cannot smoothly break away from the water droplets and penetrate to the other side, which is to prevent Water penetration occurs, making the breathable membrane waterproof
Types of waterproof and breathable fabrics: There are two main types: water-resistant and waterproof. The former is divided into fiber/cloth type (not windproof but good breathability) and membrane type (windproof but poor breathability); the latter is generally breathable. Membrane type, two or three layers, windproof, two layers are softer and more breathable than three layers, while three layers are stronger. Water-resistant or highly water repellent fabrics will seep when pressure is applied to them, such as when you sit on a wet stool wearing pants made of this material.
The development of completely waterproof and breathable fabrics (waterproof) began in the late 1970s. The current second generation products are completely waterproof and windproof and maintain good breathability. However, garments made of this kind of fabric are not necessarily completely waterproof, mainly because of water seepage in seams or zippers. To ensure that the garment is completely waterproof, you need to tape all the seams (good garments use waterproof tape). This requires a lot of labor and cost, which is one of the reasons why such clothes are so expensive.
At fabric exhibitions in Shanghai, we often encounter customers who need composite fabrics with a waterproof and moisture permeability of 10000/10000. I fainted when I heard it. As I said before, American Gore fabrics can achieve this moisture permeability. The general TPU high-permeability film can only achieve a moisture permeability of 5,000 when made into a three-in-one (surface fabric + membrane + lining). Moisture content. If you use British Porelle or Dutch Sypamtex membrane, the moisture permeability will be higher, but it cannot reach 10,000, and these imported membranes are also expensive. So how do you explain that customers require such high indicators? One possibility is that customers don’t understand this industry and see Gore’s clothes marked with 10000/10000, so they have to set such high indicators; another possibility is that they are laymen. What people don’t understand and are often exploited by some is the difference in testing methods.
How many testing methods are there now? I hope you don’t have to hold on to the methods I’ve listed!
1. Cup control method
1.1 Water vapor transmission method
1.1.1 Cup correcting method
A, Chinese national standard: GB/T12704-91-B
B, American Society for Testing and Materials standard: ASTM-E96-Produce-B-and-D
C, Japanese Industrial Standard: JIS-L-1099-A2
D, Canadian Standard: (CGSB)-4.2-No.49-99
E, British Standard: BS-7209-1990
1.1.2 Cup pouring method (also called moisture absorption method)
A. American Society for Testing and Materials standard: ASTM-E96-BW (1995 and 2000 editions)
1.2 Desiccant method
1.2.1 Cup correcting method
A, Chinese national standard: GB/T-12704-91-A
B, Japanese Industrial Standard: JIS-L-1099-A1
C, American Society for Testing and Materials standards: ASTM-E-96-A, C, E
1.2.2 Cup pouring method
A, Japanese Industrial Standard: JIS-L-1099-B1, B2
B, American Society for Testing and Materials standard: ASTM-E-96
C, Belgian UCB company standard: UCB-Law
D, British Standard: B.T.T.G method
2. Sweating hot plate method, also called skin model method
A, ISO standard: ISO-11092
B. Fire protective clothing test: NFPA-1971
C, American Society for Testing and Materials standard: ASTM-F-1868-98-B
D, German standard: DIN-54-010-T01-A
3. Sweating dummy method
The sweat dummy dummy is somewhat like a hot plate and is used to simulate the shape and size of a typical human body. The dummy test is more practical than the sweating hot plate test because it can take into account more variables, including the surface area of the body covered by the garment, the number of layers of textiles and the distribution of the air layer on the body’s surface, a loose or tight fit, and different parts of the body. skin temperature difference, body position and movement status, etc. However, there has not yet been a sweat dummy that can test evaporative thermal resistance under dynamic conditions such as walking.
Currently, there are no design standards and testing procedures for sweat dummies. And because sweating dummies are more complex and expensive, dummy testing is more expensive than the hot plate method.
4. Other methods
A, Watkins-Method
B, Mernander method
C, Farnworth method
D, Van-Beest method
E, Ruchman method
F, Gibson LawyjGJxls7a
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