2024年4月3日发(作者：影视大全2022年最新版本)

如何区别WaterproofWater RepellentWater ResistantWeather Resistant

Fabrics and garments may be labeled waterproof, water-repellent,

weather-resistant or some combination of these. But what does it all mean?

Waterproof

A waterproof fabric is completely impermeable to water.(1) Since all the pores

are closed, these fabrics are also impermeable to air and can become hot and

uncomfortable as apparel. A vinyl raincoat is an example of a waterproof garment.

The wearer remains dry since rain stays outside the coat; it can not soak into or

through the fabric. Waterproofness is easy to determine either water can get in or

it can not.

Water Repellent

Water repellence and water resistance introduce a lot more uncertainty. Water

repellency is the resistance to wetting; water resistance is the resistance to wetting

and water penetration.(2) Different fabrics resist wetting (absorbing water) to

different degrees and the AATCC Technical Manual includes two methods for

determining water repellency. AATCC Test Method (TM) 22, Water Repellency:

Spray Test calls for a visual evaluation of the wetting pattern after the fabric is

sprayed with water. Manufacturers and retailers must agree on an acceptable level

of repellency based on the end-use of each fabric. A rating of 80-90 (on a scale of

0-100) is generally acceptable for unlaundered samples intended for use as

water-repellent outerwear.(3) Water repellency tests measure the amount of water

that soaks into the fabric, not the amount that soaks through.

Intended mainly to measure the water-repellent efficacy of finishes, TM 70,

Water Repellency, Tumble Jar Dynamic Absorption Test is not intended to predict

rain penetration resistance.(4) Specimens are tumbled in water, weighed, and the

wet weight is compared to the dry weight.

Water Resistant

AATCC TM 35, Water Resistance: Rain Test and TM 42, Water Resistance:

Impact Penetration Test use the weight of the water penetrating the fabric as a

measure of resistance. Less than 1 g is usually considered acceptable;3 anything

over 5 g is reported as > 5 g and indicates failure as a water-resistant fabric.2 The

rain test may be performed at different pressures to simulate different intensities

of rain and acceptable values for both tests may vary according to end-use.

Another measure of water resistance is TM 127, Water Resistance: Hydrostatic

Pressure Test. Water is directed at one side of the fabric under increasing pressure

and the point at which water droplets appear on the opposite side is recorded.

This test differentiates between the water resistance of the fabric and the water

repellency of the fiber, yarn, and fabric construction. The degree to which the

fibers and yarns resist wetting, combined with the size, shape, and number of

pores in the fabric construction, influences the overall penetrability of the fabric.(5)

Weather Resistant

Weather resistance, the ability of a material to resist degradation of its

properties when exposed to climactic conditions,6 is an even more complicated

issue. AATCC TM 186, Weather Resistance: UV Light and Moisture Exposure

subjects fabrics to artificial weathering through the use of ultraviolet (UV) light,

humidity, and/or water spray. Exposed fabrics are compared to control fabrics in

terms of color change and breaking or bursting strength. This test is most

appropriate for items which will be placed outdoors for extended periods of time.

The test method suggests three cycle options based on end-use梘eneral

applications (e.g., outdoor furniture fabrics, and tent material), architectural

applications where thermal shock may be an issue, and automotive exteriors. The

UV and humidity/spray conditions for each application vary slightly. TMs 111, 169,

and 192 are similar tests, using different combinations of light and/or water to

simulate weathering.

So, will your fabric keep you dry?

Waterproof fabric will protect you from rain, but will eventually make you hot

and sweaty. A water-repellent fabric will probably keep you dry if you are out in the

rain for just a few minutes. Water-resistant fabrics may also keep you dry

temporarily and they will be more breathable than waterproof fabrics, but water

will eventually soak in, making the fabric heavy and wet. While a weather-resistant

fabric makes no promise to keep you dry, it will continue to look and perform as it

was intended even after prolonged exposure to sun and rain.

References

1. Dictionary of Fiber & Textile Technology, KoSa, Charlotte, N.C., U.S.A., 1999,

p215.

2. AATCC Technical Manual, Vol. 81, 2006, pp65-67, 85-88.

3. Annual Book of ASTM Standards, Vol. 7.02, West Conshohocken, Pa., U.S.A.,

2005, p992.

4. AATCC Technical Manual, Vol. 81, 2006, pp99-100.

5. AATCC Technical Manual, Vol. 81, 2006, pp211-212.

6. AATCC Technical Manual, Vol. 81, 2006, pp348-352.

Note: Story by Diana Wyman, AATCC.