 | This article or sectionis undergoing significant expansion or restructuring. You are welcome to assist in its construction by editing it as well. If this article or sectionhas not been edited in several days, please remove this template. If you are actively editing this article or section, you can replace this template with {{in use|5 minutes}}.This article waslast edited byNetstars22(talk |contribs) 0 seconds ago.(Update timer) |
 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Waterproof fabric" – news ·newspapers ·books ·scholar ·JSTOR(June 2016) (Learn how and when to remove this message) |
Waterproof fabrics are fabrics that are inherently, or have been treated to become, resistant to penetration by water and wetting. The term "waterproof" refers to conformance to a governingspecification[1] and specific conditions of a laboratorytest method. They are usually natural or synthetic fabrics that are laminated orcoated with awaterproofing material such aswax,rubber,polyvinyl chloride (PVC),polyurethane (PU),silicone elastomer, orfluoropolymers. Treatment could be either of the fabric during manufacture or of completed products after manufacture, for instance by a waterproofing spray. Examples include the rubberized fabric used inMackintosh jackets,sauna suits, andinflatable boats.
Waterproof fabrics may also includewaterproof-breathable fabrics, which are fabrics that allowwater vapor to move across the fabric while still resisting liquid water and wetting.
.jpg)
Waterproof/breathable fabrics resist liquid water passing through, but allowwater vapour to pass through. Their ability to block out rain and snow while allowing vapour from sweat to evaporate leads to their use in rainwear, waterproof outdoor sports clothing, tents, and other applications.
Standard laboratory testing protocols[which?] define the performance of these fabrics. Water resistance is measured by the amount of water, in mm, which can be suspended above the fabric before water seeps through.[citation needed] Breathability ormoisture vapor transmission rate is measured by the rate at which water vapor passes through, in grams of water vapour per square meter of fabric per 24-hour period (g/m2/d),[2] often abbreviated to just "g". In recent years[timeframe?] some,[who?] but not all, sporting goods manufacturers have begun including this information on their product labels. Typical mid-range fabrics tend to have values of 5,000 mm of water resistance and 5,000 g of breathability; the best materials have 20,000 mm and 20,000 g.
One specific definition of "waterproof/breathable" requires the fabric to withstand a pressure of over 1,000 millimetres of water (9.8 kPa) pressure without leaking (seehydrostatic head).[citation needed]
These values should be taken with some caveats. Rain room tests show that some fabrics with less than 1,000 mm of water resistance keep water out sufficiently for practical purposes.[citation needed] Garments made from these fabricstested in theLeeds University Rain Room show no signs of leakage after 4 hours of simulated rain five times heavier than heavy rain.[clarification needed] However, some garments made from fabrics that exceed 20 000 mm have leaked through zips, hoods, and seams. Fabric head ratings do not totally specify water resistance of a garment, as it does not test closures such as zips. In addition, thebreathability of nearly all waterproof/breathable fabrics is very dependent upon weather conditions, especially temperature, humidity, and wind.[according to whom?]
Fabrics such ascotton ornylon may be coated with various compounds such aswax,silicone, orpolyurethane to confer waterproof properties. The resulting fabrics (i.e.waxed cotton andsilnylon) are fully waterproof but are not considered breathable as the coating creates a fabric that blocks both liquid water and water vapor from moving across the fabric.
Woven waterproof-breathable fabrics are made from fibers that arewoven at such a high density thatwater is unable to pass through the pores of the fabric, either at all times or, in the case of textiles made fromhygroscopic fibers likeVentile, after the fabric has been exposed to water[3]. In contrast to other waterproof-breathable textiles, these fabrics do not use a membrane or coatings to achieve waterproofing.
Polyurethane laminate (PUL) textiles arecomposites that consists of a fabric such aspolyester laminated to a thin film of polyurethane to provide waterproofing.
Membrane-based waterproof/breathable fabrics use anePTFE orPVDF membrane that has pores that are large enough to allowwater vapor to pass through, but small enough that rain droplets and other precipitation cannot.[3] The membrane is laminated between an outer fabric likeripstop nylon and an inner liner, typically either a fabric liner or apolyurethane coating. Both layers provide structure to the membrane and protect it from physical damage and contamination[4].
Insportswear applications, the outer liner fabric may also be coated with adurable water repellent. The durable water repellent coating must be maintained on a regular basis to prevent a phenomenon known as "wetting out"[5], wherein the outer protective layer becomes saturated and prevents the movement of water vapor.
Waterproof/breathable fabrics are commonly used inrainwear,ski suits,cycling kits, and other types ofouterwear, where the fabric is used in a garment that is intended to maintain the wearer's comfort. Apparel applications will typically use membrane-based waterproof/breathable fabrics, such asGore-Tex.
Polyurethane laminates are often used in household applications such as waterproofmattress protectors where they provide a more comfortable alternative to vinyl mattress covers.
Polyurethane laminates are also used as materials forcloth diapers, where the polyurethane layer is used to contain fluids within the diaper.
{{citation}}: CS1 maint: work parameter with ISBN (link)
