Smart breathable fabric:
Ø It
is not possible to achieve all of desirable properties of water proof
breathable fabrics in a simple structure of any single fibre or their
blend.
Ø The
two layer structure has layer close to skin of the wicking type
comprised of synthetic fibers. e.g micro denier polyester and the outer
layer usually cotton or rayon that absorbs and evaporates.
Ø Micro denier polyester is ideal for wicking perspiration away from the skin.
Ø Dense fabric with superfine or micro fibre yarn gives the best wicking properties.
Polyester
Ø Advantages:
o Dimensional Stability.
o Excellence resistance to dust, dirt, alkalis, decay, mold, organic solvent.
o Light weight.
o Durable.
o Smooth hand feel.
o Elasticity.
o Heat resistance.
o Low Cost.
o Easy care.
Ø Disadvantages
o Low moisture absorption.
Ø Most polyester used un base layer clothing is chemically treated so that they are able to wick moisture.
Ø This can be done by
o Coating the polyester with hydrophilic finish.
o Changing its surface chemistry to improve its wetting by moisture
Ø Molecular modification
o Costly.
o Permanent(50 wash)
Ø Toray:
o Develops airfine fieldsensor.
o Grooves polyester filament yarn.
o Grooves help the fabric absorb sweat quickly and disperse it along the surface.
Ø Polyester coolmax:
o Increase wearer comfort through rapid removal of perspiration by capillary.
o Has good wicking properties and non absorbency.
o Coolmax
and thermostat polyester used in two fold garments, coolmax is used to
wick moisture away from the skin and polyester is used to maintain
warmth.
2. Polypropylene
Ø Hydrophobic nature.
Ø Has good thermal characteristics (keeping warm in cold weather and cold in warm weather).
Ø Cannot wick liquid moisture but moisture vapour can still forced through polypropylene fabric by body heat.
Ø More oleophilic than polyester.
Ø Has a great tendency to attract and hold oily body odours.
3. Nylon
Ø Advantages
o Lightweight.
o High strength.
o Durable.
o Soft hand feel.
o Higher moisture absorption than the polyester and has better wicking behaviour.
Ø Disadvantages
o Expensive.
o It dries more slowly than polyester due to its higher moisture absorption.
Ø Nylon is good fabric choice when combined with PU coating.
Ø Used in tightly woven outwear, which can trap heat because of low air permeability.
Ø Used in breathable knitted g=fabrics and premimum application.
Ø Polus - Ex:
o Developed by DuPont
o Permeable to moisture.
o Made by laminating a multi porous film to a nylon fabric and moisture permeability of 8000g/m2 /24 hours, as well as 20 m head of water.
3. Silk
Ø Advantages:
o Breaths well for its hollow structure.
o Soft
o Strong
o Has natural wicking properties
Ø Disadvantages:
o Dries Slowly.
o Requires care cleaning.
4. Viscose
Ø Not preferred next to skin as it holds water in sportswear.
Ø Wicking behaviour improves by incorporation of some hydrophobic finishes
5. Wool
Ø Not appropriate for a base layer for its 'itch'.
Ø Fibre should be very fine thus make a higher density, strength, abrasion resistence, increase warmth.
Ø Fine fiber absorb less water weight per cross sectional area, so they are more resilient than coarser fibers.
Ø Natural wicking properties.
Ø Fine cholorinated merino wool is employed is sportwool as a base layer.
Ø Disadvantages:
o Slow to dry.
Ø A wool fabric has absorb significantly more sweat than a polyester fabric.
Ø The skin temperature decreased faster and recovered more slowly after contact with the wool fabric compared polyester fabric.
5. Special Fibers:
5.1. Hygra
Ø Launched by unitika limited.
Ø Sheath core type filament yarn made from water absorbing polymer and nylon
Ø The water absorbing polymer has a special network structure that absorbs 35 times its own weight of water.
Ø Offer quick releasing properties.
Ø Nylon gives tensile strength and dimensional stability.
Ø It has superior anistatic properties even under low wet condition.
Ø Use in athletic wear, skiwear, golf wear etc.
5.2 Lumiace
Ø Product from Unitika.
Ø A collection of polyester filaments having different fineness (0.5-2.0 denier per filament) and irregular cross section.
Ø Hygra-Lumiace combination in knitted fabric is very popular in top Japanese athletes.
5.3 Dryarn
Ø Fiber from aquafil.
Ø Completely recyclable polyproplyene microfibers.
Ø Lightweight, comfortable, use in different sports.
Ø Soft handle.
Ø High thermoregulatory.
Ø Dries quickly.
Ø Avoids unpleasant odour associated with bacteria.
5.4 Killat N
Ø Nylon hollow filament from Kenebo Ltb.
Ø Hollow portion is about 33% of the cross section of filament.
Ø Gives good water absorbency and warmth retentive property.
Ø The
yarn is spun as bio component filament yarn with soluble polyester
copolymer as the core portion and nylon as the skin portion.
Ø Soluble polyester copolymer is dissolved by alkali treatment and a hollow portion is crated.
5.5 Triactor
Ø Developed by Toyoba Co. Ltd.
Ø Quick sweat absorbency by capillary action due to Y shaped cross section.
Ø First drying.
5.6 Field Sensor (Smart Breathable Fabric)
Ø Very popular high performance fabric from Toray.
Ø Multi layer structure.
Ø Absorb perspiration quickly and transport it up to the outer layer of fabric very rapidly by capillary action.
Ø Composed
of coarser denier yarn on the inside surface and fine denier
hydrophobic polyester yarn in a mesh construction on the outer surface
to accelerate quick evaporation of sweat.
5.7 Naiva (Smart Breathable Fabric)
Ø Developed by Unitika.
Ø Combining the Naiva yarn with a nylon microfibre.
Ø Naiva is an Eval/Nylon bi-component filament yarn.
Ø Eval is a copolymer resin of ethylenevinylalchol.
Ø Composition 55% Eval and 45% nylon.
Ø Many micro loops on the surface, which are formed by making use of high thermal shrinkage property of Naiva yarn,
Ø Good moisture permeability.
Ø Lightweight.
Ø Soft.
Ø Use in active sportswear.
5.8 Entrant Dermizax EV (Smart Breathable Fabric)
Ø Lightweight fabric.
Ø Have feather smooth texture.
Ø Excellent water proof.
Ø Excellent moisture permeability.
5.9 Entrant HB (Smart Breathable Fabric)
Ø New generation fabric.
Ø Hybrid structure that synergistically integrates the advantages offered by a coating and lamination.
Ø HIgh resistance to water pressure.
Ø High durability.
Ø Used in outdoor wear.
5.10 H2OFF (Smart Breathable Fabric)
Ø Made up of polyester microfibre fabric.
Ø High density weave structure comprising millions of microcrimped fiber loops.
Ø Superb and durable water repellency.
Ø Superior breathability.
Ø Wind chill resistance.
Ø Attractive with soft handfeel.
Assessment technique
Assessment of the effectiveness of water proof breathable fabric requires measurement of three properties
1. Resistance to penetration and absorption of liquid water.
2. Wind resistance.
3. Water vapour permeability.
Comparision of Budesmann simulated shower and actual rain
Type of Drop
|
Diameter(mm)
|
Terminal Velocity (cms-1)
|
Kinetic Energy (J X 10-6)
|
Cloud Burst
|
0.30
|
700
|
346
|
Excessive rain
|
0.21
|
600
|
87
|
Heavy rain
|
0.15
|
500
|
22
|
Moderate rain
|
0.10
|
400
|
4.2
|
Light Rain
|
0.045
|
20
|
0.095
|
Drizzle
|
0.02
|
75
|
0.0012
|
Bundesmann
|
0.64
|
540
|
2000 |
No comments:
Post a Comment