This is how we test the waterproof performance of fabrics

Good-quality waterproof fabrics can withstand the pressure of water seepage even if they are exposed to humid climates for a long time without water seepage. For example, if you walk outdoors in wind and rain for a long time, kneel or sit on wet ground, there will be no water leakage. Waterproof fabrics are generally divided into several basic types: PTFE, FEP, PFA, and ETFE. 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 fabric).

How to detect waterproof fabrics?

Waterproof fabrics are commonly used in outdoor clothing such as jackets. There are various testing methods for waterproof fabrics. This article only briefly introduces several methods that are commonly used and have accurate testing results.

At present, the commonly used waterproof fabric testing methods at home and abroad mainly include the water vapor cup method standard by the American Society for Testing and Materials; and the Japanese Industrial Standard testing method.

The United States has always been in a leading position in the waterproof fabric industry, and the country’s market is also very large. The test data of this method is also relatively high, and the ASTM standard has naturally become a commonly used method. Most customers now use this method for testing.

The test principle of the water vapor inverted cup method is to cover the fabric to be tested on a breathable cup filled with 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 in the position of the wind tunnel row. superior.

Before the cup enters an environmental chamber with a temperature of 23°C, a relative humidity of 50%, and a wind speed of 2.5m/s for weighing, record the temperature and relative humidity of the environment.

The weight of each cup and the time it took to weigh it were recorded. Record the weight at 3h, 6h, 9h, 13h, 23h, 26h, and 30h, and use the formula wvt=24*△m/(s*t) to calculate the water vapor transfer rate. The average value of 6 samples is used as the test result. The average value is multiplied by 24 and converted to the result in g/m2*24h.

Waterproof fabrics are made of textiles that are oil-repellent, water-repellent and water-pressure resistant.

The method with high test results for this kind of fabric is JIS L-1099 b1, b2 Japanese industrial standard testing.

Hoop the PTFE film on the plastic cup with a rubber ring to create a water vapor permeable cup.

Before wrapping the film on the cup, put enough liquid into the water vapor-permeable cup to fill about 2/3 of the cup’s volume.

Take 3 samples of 20cm*30cm square from each fabric. Each sample is placed on a test support frame.

All coated or laminated fabrics are secured to the support frame with rubber rings, with the coated or laminated side facing outward.

The installation of the sample support system shall be subject to being able to float in a water tank with a water temperature of 23°C. After testing the quality of the test cup (including sample, desiccant and film) with the film facing upwards, quickly turn the test cup upside down and place it into the sample holder. This assembly method is placed in a constant temperature device of 30℃±2℃.

After 15 minutes, take the test cup out of the thermostatic device, turn it upside down and measure its weight.