Water proof breathable fabrics by Vignesh Dhanabalan

Waterproof Breathable Fabrics: Technologies and Practices

By Vignesh Dhanabalan12M.Tech13

INTRODUCTION

20000 times smaller than a drop of liquid water, but 700 times larger than a water molecule

Effective transmission of moist vapor from inside to outside atmosphere but rendering water transportability.

Actively ventilated.

14/3/2014 Vignesh Dhanabalan (M.Tech) - [email protected]

Principles of moisture vapor transfer

Absorption, transmition and desorption of the water vapor by the fibers.

Diffusion of the water vapor through the air spaces between the fibers.

Transmition of water vapor by forced convection


TRANSPORT

MECHANISM

Capillary’s diameter and surface energy

Capillary pressure and capillary raise are determined using

P = 2γLV cos / Rc , L = ((Rcγ cos /2)* t1/2

P = capillary pressure L = liquid pressure

Rc – capillary radius t and - time and viscosity


Properties required for breathable fabrics

Soft feel, light weight and Durable

Easy care/launderability

Rapid drying to preventcatching cold.

Good air and water vapor permeability.Rapid moisture absorption and conveyance capacity

Optimum heat and moisture regulation (thermo-regularity effect)

Absorption of surplus heat.

Dimensionally stable even when comes in contact to water

No/Minimum water absorption of the layer of clothing just positioned to the skin.


Producing breathable fabrics

Smart Breathable fabrics (PCP)SMP – PU material Micro porous Membrane

Densely Woven Fabric (Micro denier<10 micron)

Closely woven fabrics(oxford weave) up to 20 min


Cont……

Various methods for generating microspores membrane and coating

•Mechanical fibrillation (Film) - PTFE films – biaxial stretched- negative poissons

ratio - 50– 400 µm – crystallinity of polymer >98% - 9 billion pores /inch2 -

•Wet coagulation - ultrafine pores < 1µm – salt leaching - Requires Precise

control below 3 µm.

•Thermo coagulation - volatile solvent - PU dissolved in methyl ethyl ketone,

toluene, and water, having 15–20% solid

•Foam coating - fluorocarbon (FC) polymer, PU coating – soft n flexible - abrasion

•Radio frequency (RF)/ion/UV or E beaming - Sputtering of Teflon by Ar gas


Application of Polyurethane coating

• Pore dia of 0.0004 µm possible

•PU-based film designed (Permatex) by J.B. Broadley coated on fabrics offers a

vapor permeability of at least 70%.

•Grabotter membrane (Grabo Ltd.) used in waterproof shoes is a PU-based film.

•Micro porous PU film is being produced by Acordis (Tarka) is applied by a

transfer process from the release paper and it can be applied to almost any type

of substrate.

Knife coating

Floating knife

Extrusion

Calendaring

Curtain coating

Gurave coating

Reverse roll


Testing of Breathability of Fabrics using different techniques

S.no Methodology Standard Purpose

1 Sweating Guarded Hot Plate

Tests

(ISO 11092, ISO

1999, and ASTM F

1868)

Measurement of thermal and water-vapor resistance under

steady-state conditions

2 Upright Cup Method ASTM E96 Water Vapor Transmission of Materials , permeability,

plastics (general), plastic sheet and film, sheet material3 Inverted Cup Method ASTM E96

4 Desiccant Inverted Cup Test

Method

E96 M-05

5 Dynamic Moisture

Permeation Cell Test

ASTM F 2298

Standard Test Methods for Water Vapor Diffusion

Resistance and Air Flow Resistance of Clothing Materials

Using the Dynamic Moisture Permeation

6 Moisture vapor transmition

cell

ASTM D1653 - 13 Moisture vapor transmition behavior of fabric

7 Dynamic moisture

permeable cell

ASTM F2298-

03(2009) e1Moisture transmition capability of cell


Relative water vapor permeability (%)

Heat loss when the fabric is placed on the measuring head X 100Heat loss from bare measuring head

The main requirements for WVPI are based on

•Water vapor permeability index percentage.

•Resistance to water penetration.

•Cold cracking temperature.

•Surface wetting (spray rating) after cleaning.

For a typical breathable fabric the acceptable parameters should have

•Water-vapor permeability (min 5000gm-2 for 24 hrs)

•Water proofness min 130 cm (hydrostatic pressure)

•Wind proofness less than 1.5 ml/cm2/second @ 1M bar


Water Proof ratingWaterproof Rating

(mm)Resistance provided Withstand capabilities

0-5,000 mmNo resistance to some resistance

to moistureLight rain, dry snow, no pressure

6,000-10,000 mmRainproof and waterproof under

light pressureLight rain, average snow, light pressure

11,000-15,000 mmRainproof and waterproof except

under high pressure Moderate rain, average snow, light pressure

16,000-20,000 mmRainproof and waterproof under

high pressureHeavy rain, wet snow, some pressure

20,000 mm+Rainproof and waterproof under

very high pressureHeavy rain, wet snow, high pressure

For example : 10000/10000 – First number represents water proofness of fabric and second number represents breathability of the fabric. Higher the value better is the result


http://www.evo.com/shop/clothing/outerwear/waterproof_000-mm.aspx

http://www.evo.com/shop/clothing/outerwear/waterproof_000-10-000.aspx

http://www.evo.com/shop/clothing/outerwear/waterproof_11-000-15-2.aspx

http://www.evo.com/shop/clothing/outerwear/waterproof_16-000-20-3.aspx

http://www.evo.com/shop/clothing/outerwear/waterproof_20-000-mm-2.aspx

Application

3M incise tape 9948Neo-G knee support

Breathable snow protect mountain wear

Fire man Protective Apparel

Racer Suite

Ventile Roofing Membrane

Somatex Casing layer

14/3/2014 Vignesh Dhanabalan (M.Tech) [email protected]

Conclusion

• Comfort property has become the most prime objective of the buyer/consumer where breathability of the fabric with water proofness has been the primary importance in areas that do not enjoy the evergreen nature.

• Extensive research is required to understand the relationship between segmental ventilation and local comfort of the fabric subjected to active usage of the person.


Thank you

Vignesh Dhanabalan12M.Tech13


Bibliography• Arunangshu Mukhopadhyay and Vinay Kumar Midha, “A Review on Designing the Waterproof

Breathable Fabrics Part I, Fundamental Principles and Designing Aspects of Breathable Fabrics” , Journal of Industrial Textiles 37: 225, (2008).

• Apurba das and R.Alagiruswamy, “Science in clothing comfort”, Woodhead publications, ISBN 13:978-81-908001-5-0, (2010).

• Shishoo.R, “Textiles for Sport”, Woodhead publications, ISBN 978-1-85573-922-2, 2005.

• Williams.J.T, “Textiles for cold weather apparel”, Woodhead publications, ISBN 978-1-84569-411-1, (2009).

• Horrocks.A.R, Anandh.S.C, “Handbook of technical textiles”, Woodhead Publishing Limited, ISBN 1 85573 385 4, (2000).

• Shirley Institute, Toray Industries Inc., Naka, Y. and Kawakami, K. (1985).Moisture-Permeable Waterproof Coated Fabric, USP 4560611, December: 8602376

• Manjeet Jassal, Amit Khungar, Pushpa Bajaj and T. J. M. Sinha, “Waterproof Breathable Polymeric Coatings Based on Polyurethanes”, Journal of Industrial Textiles 33: 269, (2004).

• Rudolph D. Deanin AND Dhirajlal C. Patel, Breathable, Permanent Water-Repellent Treatment of C1ot, Textile Research Journal; 40; 970, (1970).

• Volkmar T. Bartels and Karl Heinz Umbach, “Water Vapor Transport through Protective Textiles at Low Temperatures”, Textile Research Journal 72: 899, (2002)


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