The waterproof fabric with good quality can withstand the pressure of water seepage without water seepage in the humid climate environment for a long time. For example, if you walk outdoors for a long time, kneel or sit on the wet ground, there will be no water seepage. Waterproof fabrics are generally divided into several basic types: PTFE, FEP, PFA and ETFE. The general TPU high permeable membrane can only achieve a moisture permeability of 5000 when it is made of three in one (top cloth + membrane + lining).
How to test waterproof fabric?
Waterproof fabric is a kind of common fabric for outdoor clothing, such as charge clothes. The detection methods of waterproof fabric are various. This paper simply introduces the most commonly used and the most accurate methods.
At present, the most commonly used testing methods of waterproof fabric at home and abroad mainly include the American Society for testing materials standard water vapor pouring cup method, and the Japanese industrial standard testing method.
The United States has always been in the leading position in the waterproof fabric industry, and the market in the country is also very large. The test data of this method is relatively high, and the ASTM standard naturally becomes the most commonly used method. Now most customers use this method for testing.
The principle of water vapor pour cup method is to cover the tested fabric on the moisture permeable cup containing distilled water, fix it and turn it upside down, weigh it with a top loading balance with an accuracy of 0.001g, and place it on the position of the wind tunnel row.
Record the temperature and relative humidity of the environment before the cup enters the environment room with temperature of 23 ℃, relative humidity of 50%, and wind speed of 2.5m/s for weighing.
The weight of each cup and the time of weighing are recorded. Record the weight at 3h, 6h, 9h, 13h, 23h, 26h and 30h, and calculate the water vapor transfer speed with WVT = 24 * △ M / (s * t). The average value of 6 samples is taken as the test result, and the average value multiplied by 24 is converted into the result in g / m2 * 24 h.
The textile fabric of waterproof fabric has the properties of oil repellent, water repellent and water pressure resistant.
The highest test result of this kind of fabric is JIS l-1099b1, B2 Japanese industrial standard test.
The PTFE film is made into a water vapor permeable cup with a rubber band on the plastic cup.
Before coating the film on the cup, put enough liquid into the water vapor permeable cup, and fill the cup with a volume of about 2 / 3.
Take 3 samples of 20cm * 30cm square from each fabric. Each sample is placed on a test stand.
All coated or laminated fabrics shall be fixed to the support frame with rubber rings and the coated or laminated surface shall face outwards.
The sample support system shall be installed in a water tank with a temperature of 23 ℃. After the test cup mass (including sample, desiccant and film) is tested in the upward direction of the film, quickly turn the test cup upside down and put it into the sample support frame. This assembly method is placed in a device with a constant temperature of 30 ℃± 2 ℃.
After 15 minutes, take out the test cup from the thermostatic device, turn it upside down and measure its weight.
The above is the most practical method of waterproof fabric testing at home and abroad. Most of the waterproof fabrics tested by these methods can achieve the effect of waterproof and moisture-proof.
