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Breathable fabric

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Antistatic finish in textile
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Breathable fabric

  1. 1. Breathable Fabrics or waterproof breathable/waterproof-breathable Some important points Waterproof fabric completely prevents the penetration and absorption of liquid water. Breathable fabric is actively ventilated and it passively allow water vapor to diffuse through them yet prevents the penetration of liquid water. Waterproof breathable fabrics resist water droplets from passing through while at the same time allowing water vapor through. The breathability of almost all waterproof breathable fabrics is very dependent upon weather conditions, especially temperature and humidity. Waterproof breathable fabrics are widely used in sportswear and similar Application.
  2. 2. Breathable Fabrics or waterproof breathable/waterproof-breathable Breathability is measured by the rate at which water vapor passes through in the units of grams of water vapor per square meter of fabric per 24 hours period (g/m2/d), often abbreviated to just ‘g’. In recent years some of the sporting goods manufacturers have begun including this information on their labels. Typical mid-range fabric tends to have values of 5000 mm of water resistance and 5000g of breathability. The highest end materials boast 20000 mm and 20000 g.
  3. 3. Breathable Fabrics and Applications or waterproof breathable/waterproof-breathable
  4. 4. Waterproof Breathable Fabric Drops of water (10000-2000000A diameter) are too big to penetrate the membrane wind Perspiration vapor (3.5A) passes through inter-molecular opening easily
  5. 5. Uses of Waterproof Breathable Fabric Leisure Work Heavy duty, foul weather clothing: Anoraks, cagoules, packs , over-trousers, hats, gloves, gaiters Foul weather clothing: survival suits, special military protective clothing, clean room garments, surgical garments, hospital drapes, mattress and seat covers, specialized tarpaulins, packaging, wound dressings ,filtration Domestic and transport: non-allergic bedding, car covers, fire smoke curtains in ships, cargo wraps in aircraft Fashionable weather protection: rainwater, skiwear, golf suits, walking boot linings, panels and inserts, sport footwear linings, panels and inserts Tents Sleeping bag covers
  6. 6. Examples of Breathable Fabrics Anorak Cagoule Gaiter Gaiter
  7. 7. Examples of Breathable Fabrics
  8. 8. Types of waterproof breathable fabric There are several types of waterproof breathable fabric. These can be divided into three groups: Densely woven waterproof breathable fabrics Membranes/Laminated waterproof breathable fabrics Coated waterproof breathable fabrics
  9. 9. Waterproof Breathable Fabric Densely Woven • For cotton, the finest type of long staple are selected so that there are very small space between the fibers. The cotton is processed into combed yarn, which is then plied. This improves regularity and ensures that the fibers are as parallel as possible to the yarn axis, and that there are no large pores where water can penetrate. The yarn is woven using an oxford weave, which is a plain weave with two threads acting together in the warp. This gives maximum crimp in the weft, again ensuring that the fibers are as parallel as possible to the surface of the fabric. When the fabric surface is wetted by water, the cotton fibers sell transversely reducing the size of the pores in the fabric and requiring very high pressure to cause penetration. This fabric is thus become waterproof without the need for water-repellent.
  10. 10. Waterproof Breathable Fabric Densely Woven Densely woven fabric can be made from synthetic microfilament yarns. The individual filaments are less than 10 micrometer in diameter, so that fiber with very small pores can be engineered. Microfilaments are usually made from polyamide or polyester. The latter is particularly useful as it has inherent water-repellent properties. The water penetration resistance of the fabric is improved by application of silicone or fluorocarbon finish. The use of very fine fibers and microfilaments and dense construction (sett) results in fabric with very small pores size compared with conventional fabrics. Typical pores size for a waterproof fabric is about 10um compared to 60um for a conventional fabric. Fabric made from microfilaments is claimed to have up to 7000 filaments per centimeter.
  11. 11. Waterproof Breathable Fabric Fig: Maximum crimp in weft Warp Weft
  12. 12. Microscopic View Scanning Electron Micrograph of Densely woven Fabric Photomicrograph of Densely woven Fabric (Dry) Photomicrograph of Densely woven Fabric (Wet)) Scanning Electron Micrograph of Microfilament Fabric
  13. 13. Waterproof Breathable Fabric Membranes/Laminated waterproof breathable fabrics: are made by application of membranes into textile product. These thin membrane made from polymeric materials. This offer high resistance to water penetration but allow water vapor. The maximum thickness of the membrane is 10micron. They are two types: Micro porous membranes Hydrophilic membranes • Micro porous membranes Micro porous membrane is a thin film of expanded polytetrafluoroethylene • The membrane contains tiny holes which are much smaller than the finest raindrop but much larger than a water vapor molecule. • The hydrophobic nature of the polymer and small pore size requires very high pressure to cause water penetration.
  14. 14. Hydrophilic membranes • Hydrophilic membranes are very thin films of chemically modified polyester or polyurethane containing no holes which therefore are sometimes referred to as non-poromeric. • The polyester or polyurethane polymer is modified by incorporating up to 40% by weight of poly(ethylene oxide) • The poly(ethylene oxide) constitutes the hydrophilic part of the membrane by forming part of the amorphous regions of the polyurethane polymer system. • These amorphous regions are described as acting like intermolecular pores’ allowing water vapor molecules to pass through but preventing the penetration of liquid water owing to the solid nature of the membrane.
  15. 15. Figure that differ coated Laminated fabric
  16. 16. Methods of Membrane incorporation There are four main methods of incorporating membranes into textile articles. The method employed depends on cost, required function and processing condition, 1 Laminate of membrane and outer fabric (Fig. a) – The membrane is laminated to the underside of the outer fabric to produce a two-layer system. Advantage:1.Has very effective protective properties like waterproof, wind resistance. Disadvantage:1.This method produces a rustling ,paper-like handling apparel. Use: mainly used in protective clothing.
  17. 17. Methods of Membrane incorporation Liner or insert processing (Fig. b) – The membrane is laminated to a light- weight knitted material or web. This structure is then loosely inserted between the outer fabric and the liner. The three materials (outer, laminate and lining) are joined together by concealed stitch seams. Advantage :1.This method gives soft handle good drape properties 2.In this method ,the outer fabric can be modified to suit fashion demand.
  18. 18. Methods of Membrane incorporation Laminate of membrane and lining fabric (Fig. c) – The laminate is attached to the right side of the lining material. -The functional layer is incorporated into the garment as a separate layer independent of the outer fabric. Advantage: In this method the fashion aspects can be maximized.
  19. 19. Methods of Membrane incorporation Laminate of outer fabric, membrane and lining (Fig. d) – This produces a three-layer system, which gives a less attractive handle and drape than the other methods and, therefore, is not commonly used.
  20. 20. Coated waterproof breathable fabrics: consist of polymeric material applied to one surface of fabric. Polyurethane is used as coating material. The coatings are of two types: Micro porous Coating Hydrophilic Coating
  21. 21. Figure of Micro porous coating
  22. 22. • Micro porous Coating • Micro porous coatings have a similar structure to the micro porous membranes. • The coating contains very fine interconnected channels, much smaller than the finest raindrop but much larger than a water vapour molecule Micro porous Coating
  23. 23. Hydrophilic coating • Hydrophilic coating: It uses the same basic water vapour permeability mechanism as the hydrophilic membranes. • These coatings are all based on polyurethane, which has been chemically modified by incorporating polyvinyl alcohols and polyethylene oxides. These have a chemical affinity for water vapour allowing the diffusion of water vapour through the amorphous regions of the polymer
  24. 24. Figure of Waterproof coating
  25. 25. Desirable Attributes of WBF for Sportswear Optimum heat and moisture regulation Good air and water vapor permeability Rapid moisture absorption and conveyance capacity Absence of dampness Rapid drying to prevent catching cold Low water absorption of the layer of clothing just positioned to the skin Dimensionally stable even when wet Durable, Easy care lightweight, Soft and pleasant touch Does it possible to maintain above mentioned qualities in one fabric?
  26. 26. How to get these attributes? Two layer structures are needed. The first layer closed to skin should be of the wicking property, made of synthetic fibers, e.g., micro-denier polyester. The outer layer usually cotton that absorbs and evaporates the perspiration/water vapor. The first layer is ideal for wicking perspiration away from the skin. Wicking refers to technical property in fabrics that move sweat away from the skin to the outer surface of the fabric where it evaporates
  27. 27. Moisture Transport Mechanism The mechanism by which moisture is transported in textiles is similar to the wicking of a liquid in capillaries. Capillary action is determined by two fundamental properties of the capillary: Its diameter, and Surface energy of its inside face. The smaller the diameter of the greater the surface energy (hydrophilic action), the greater the tendency of a liquid to move up the capillary. In textile structures, the space between the fibers effectively form capillaries. Hence, the narrower the spaces between these fibers, the greater the ability of the textile to wick moisture. Fabric constructions, which effectively form narrow capillaries, pick up moisture easily. Such constructions include fabrics made from micro fibers are packed closely together. However, capillary action ceases when all parts of a garments are equally wet.
  28. 28. Factors affecting Moisture Transport There are several factors, which affect moisture transport in a fabric. The most important are: Fiber type Cloth construction or weave Weight or thickness of the materials Presence of chemical treatments
  29. 29. Assessment Techniques Assessment of the effectiveness of waterproof breathable fabrics requires measurement of three properties: Resistance to penetration and absorption of liquid water Wind resistance Water vapor permeability.

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