Water proof breathable fabrics by Vignesh Dhanabalan

Waterproof
Breathable Fabrics:
Technologies and
Practices
ByVignesh Dhanabalan
12M.Tech13

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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) - vigneshdhanabalan@hotmail.com

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

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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 prevent
catching 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 ofTeflon 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) e1
Moisture transmition capability of cell

Relative water vapor permeability (%)
Heat loss when the fabric is placed on the measuring head X 100
Heat 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 rating
Waterproof Rating
(mm)
Resistance provided Withstand capabilities
0-5,000 mm
No resistance to some resistance
to moisture
Light rain, dry snow, no pressure
6,000-10,000 mm
Rainproof and waterproof under
light pressure
Light rain, average snow, light pressure
11,000-15,000 mm
Rainproof and waterproof except
under high pressure
Moderate rain, average snow, light pressure
16,000-20,000 mm
high pressure
Heavy rain, wet snow, some pressure
20,000 mm+
very high pressure
Heavy 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

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) -
vigneshdhanabalan@hotmail.com

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 Dhanabalan
12M.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 IndustrialTextiles 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 IndustrialTextiles 33: 269, (2004).
• Rudolph D. Deanin AND Dhirajlal C. Patel, Breathable, Permanent Water-Repellent Treatment of
C1ot,Textile Research Journal; 40; 970, (1970).
• VolkmarT. Bartels and Karl Heinz Umbach, “WaterVaporTransport through ProtectiveTextiles at
LowTemperatures”, Textile Research Journal 72: 899, (2002)

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