How to test the waterproof performance of oil- and water-repellent fabrics?

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.

Water-repellent fabrics are generally divided into several basic types: polytetrafluoroethylene, FEP, PFA, and ETFE. The general TPU high-permeability film can only be made into a three-in-one (fabric + membrane + lining) Reach 5000 air permeability.

How to detect water-blocking fabric?

Water-blocking fabric is a commonly used fabric for outdoor workwear such as Outdoor Jackets.

There are many methods for testing water-blocking fabrics. This article only briefly introduces a few methods that are commonly used and have accurate testing results.

At present, the commonly used testing methods for water-blocking fabrics at home and abroad include the Japanese Industrial Standard Testing Method of Water Vapor Cup Method Standardized by the American Society for Testing and Materials.

The United States has always been in the leading position in the water-blocking fabric industry, and the country’s market is also particularly large. The test data of this method is also relatively high, so the ASTM standard has naturally become a commonly used method.

Most customers now adopt this method for testing.

Water vapor inverted cup method testing principle The fabric to be tested is immediately covered with a breathable cup filled with distilled water, fixed and inverted, weighed using a top-loading balance with an accuracy of 0.001g, and weighed Placed in the position of the wind tunnel row.

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.

The fabric of water-blocking fabric has the properties of oil repellency, water repellency and water pressure resistance.

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

Test principle as a desiccant.

Hoop the PTFE film on the plastic cup with a rubber ring to make 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 out 3 samples of 20cm*30cm square from each fabric. Each sample is placed on a test support frame.

All PU coated or laminated fabrics are fixed on the support frame with rubber rings, and the PU coated or laminated side faces outward.

The sample support system must be installed in a water tank with a water temperature of 23°C. After testing the quality of the test cup (including the 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.

The above are the useful methods for testing water-blocking fabrics at home and abroad. Most of the water-repellent fabrics that pass these testing methods can achieve water-blocking and moisture-proof effects.

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