This document discusses various technologies and methods for creating waterproof breathable fabrics. It describes two main types of membranes used - micro porous and hydrophilic membranes. Methods of applying membranes include laminating, liner/insert processing, and laminating the membrane between outer and lining fabrics. The document also discusses testing methods for waterproofness and breathability, common standards, and applications of breathable fabrics such as in mechanical counter pressure suits, outdoor apparel, and neoprene sportswear.

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Technical
Review
Issue: October ,
2013
Waterproof breathable fabrics: Technologies and practices
Laga S.K. Vignesh Dhanabalan and Joshi Rashmi M.
D.K.T.E.S Textile & Engineering Institute, Ichalkaranji-416115(M.H), India
Email: swapan.laga@gmail.com, vigneshdhanabalan@hotmail.com, xpress.joshi99@gmail.com
This article is published in two parts, this is the second part. Please continue reading from the previous issue.
6. Method employed for application of coating
The lamination process has to be chosen carefully to ensure that the breathability of the laminate is maintained at a high level.
There are four main methods of incorporating membranes into textile
Laminate of membrane and outer fabric
Liner or insert processing
Laminate of membrane and lining fabric
Laminate of outer fabric, membrane and lining
6.1 Laminating
Laminating waterproof breathable fabrics are made by application of membranes onto textile product. They are thin membrane
made from polymeric materials that offer high resistance to water penetration but allow water vapor at the same time. The
maximum pore size of the membrane is around 10 micron. They are of two types:
1) Micro porous membranes 2) Hydrophilic membranes
Micro porous membranes have tiny holes on their surface smaller than a rain drops but larger than water vapor molecule. Some of
the membranes are made from Polytetrafluroethylene (PTFE) polymer, Polyvinylidene fluoride (PVDF) etc,. The hydrophilic
membranes are thin films of chemically modified polyester or polyurethane. The poly (ethylene oxide) constitutes hydrophilic part of
the membrane by forming amorphous region in the main polymer system. This amorphous region acts as intermolecular pores
allowing water vapor molecules to pass through but, preventing the penetration of liquid water due to the solid nature of the
membrane.
Fig 4: Laminated waterproof breathable fabrics
7. Breathable, Permanent Water-Repellent Treatment of Cotton
Rudolph d. Deanin made etherification on cotton to determine Breathable permanent Water-Repellent Treatment and stated that
cotton fiber or fabric treated commercially with long chain aliphatic acid chlorides in hot organic amine baths by a rapid economical
process. To cause low degrees of etherification and produce good water repellency and dry-cleaning resistance, with no loss of
vapor permeability was observed [8].
8. Nano web on water proof and breathability
Hae Wook Ahn et al studied and compared the waterproof and breathable properties of clothing made from an electrospun
nanoweb and conventional coating of PTFE, and have stated results that, the Nano web laminate had a higher water vapor
transmission rate but lower water resistance than the polytetrafluroethylene laminate. The water penetration tests carried suggested
that water resistances are sufficient enough to prevent wetting by rain. The wearing test revealed that Nano web laminated clothing
provided more comfortable clothing-microclimate than polytetrafluroethylene laminated clothing in normal warm environment. In the

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provided more comfortable clothing-microclimate than polytetrafluroethylene laminated clothing in normal warm environment. In the
rainy test conditions, no difference was observed between the polytetrafluroethylene and the Nano web laminated clothing in any of
the measured variables [9].
Roohollah Bagherzadeh studied Transport properties of multi-layer fabric based on electro spun nanofibers mats as a breathable
barrier textile material and found that Multi-layered electro spun nanofibers mats equipped fabric (MENMEF) showed better
performance in windproof property better than Gortex fabric. Also, the water vapor permeability of MENMEF was in a range of
normal woven sport and work clothing. Comparisons of barrier properties of MENMEF and conventionally PTFE coated
materials showed that, the properties obtained by conventional PTFE could be achieved by layered fabric systems with electro
spun Nano fiber mats [10].
9. Water Vapor Transport through Protective Textiles at Low Temperatures
Volkmar T. Bartels et al studied on water vapor transport at low temperatures and have stated that the moisture accumulation in
clothing are much better in breathable than in non breathable garments (These differences are highly significant on a level of at least
p > 0.995). The ability to transport water vapor and the physiological function of breathable foul weather protective clothing
existed at subzero ambient temperatures down to -20°C [11].
10.1 Testing of waterproof breathable fabrics
The many methods employed to test the water vapor permeability of the fabric they are
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 material
3 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
Moisture vapor transmition behavior of fabric
7 Dynamic moisture
permeable cell
Moisture transmition capability of cell
8 Holographic bench
technique
Calculating mass flow
10.2 Waterproof 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
Rainproof and waterproof under high
pressure
Heavy rain, wet snow, some pressure
20,000 mm+
Rainproof and waterproof under very high
pressure
Heavy rain, wet snow, high pressure
10.3 Calculation of permeability index
The permeability index was developed by woodcock
Im = Rt/(LR x Ret)
Where Rt - the total thermal resistance of the clothing plus surface air layer (m2 ºC/W).
Ret - total evaporation resistance of the clothing plus the air layer (m2 kPa/W).
Rt/Ret – the ratio represents effective heat transmition.
LR (lewis relation) - the ratio of evaporative mass transfer coefficient.
10.4 Acceptance standard level worldwide for water repellent breathable fabrics
BS 7209 is a standard widely acceptable throughout the world for the water vapor permeable index (WVPI). The good breathable

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BS 7209 is a standard widely acceptable throughout the world for the water vapor permeable index (WVPI). The good breathable
fabric should have a minimum of 80% and lower grade should have at least 50% WVPI.
10.5 The relative water vapor permeability (%) is govern by
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.
Similarly, 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
11. Labeling of a water proof fabric and the breathable characteristics
Manufacturers describe the waterproof breathability of fabrics using two numbers. The first is in millimeters (mm) and is a measure
of how waterproof a fabric is. In the case of a 10k or 10,000 mm fabric, if a square tube with inner dimensions of 1” x 1” over a
piece of said fabric is set, it will be filled with water to a height of 10,000 mm (32.8 feet) before water would begin to leak through.
The higher the number, the more waterproof the fabric. The second number is to measure how breathable the fabric is, and it is
normally expressed in terms of how many grams (g) of water vapor can pass through a square meter (m2) of the fabric from the
inside to the outside in a 24 hour period. In the case of a 20k (20,000 g) fabric, this would be 20,000 grams. Larger the number,
higher the breathability of the fabric.
12. Application of breathable fabrics in end products
12.1 Mechanical Counter Pressure (MCP) Suit.
A skin-tight suit for high tech cloth exerts pressure over the rocketer's body to provide pressure. Open pores in the suit actually
allow the body to be cooled by perspiration. Tears will cause bruising to the skin, but are not as lethal as they are on a conventional
suit. These materials provide 20% energy expenditure compared with NASA suit [13].
12.2 Air Permeable Outerwear
Gore tech, Polartec Neoshell and Mountain Hardwear Dry.Q allow a nominal amount of airflow, helping to more quickly and
effectively carry moisture away from your body. Meanwhile, they remain totally water and windproof. You get breathability
comparable to a soft shell and waterproofing on par with a hard shell. You stay 100 percent dry from the inside and out.
12.3 Neoprene sports wear
Stomatex “breathable neoprene” is made from closed-cell foam neoprene. These fabrics can be applied as laminates or loose
linings according to users’ requirements. The product is suitable for use wherever thermal insulation or body protection is required
and comfort would normally be compromised by sweating. It has already been used in wide-ranging application including
orthomedical supports, sports supports, back supports, equestrian underwear, surface water sports, wetsuits, survival suits, surfing
wetsuits, warm-up suits, dive suits, liners and footwear [15].
12.4 Mountain wear
Mountain Hardwear's Dry.Q water-proof breathable fabric is among a new breed of sporting apparel [14]
Fig 5: Breathable snow protect mountain wear
12.5 Medical Fabric Waterproof and Breathable

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Eastex Medical Fabrics include 100% polyester and polyester-nylon blends offered in several stretch and non-stretch constructions
with different coatings to match specific product requirements. Fluid-proof, breathable, antimicrobial, flame-retardant, and air-tight
for manufacturing inflatable products, these healthcare fabrics can be sewn and sonic- or RF welded. A full line of fabrics for
OEMs and contract manufacturers of healthcare products such as wheelchair cushions, mattresses, and orthopedic braces [18].
12.6 Neo-G MEDICAL GRADE OPEN PATELLA KNEE SUPPORT 'breathable design
Used For - strains, sprains and instability, injured, weak or arthritic knees, patellar tracking, rehabilitation, sporting and
occupational injuries
Fig 6: Neo-G knee support
12.7 3M™ Conformable Breathable Incise Tape 9948
The Conformable Incise Tape is a single coated medical tape consisting of a 1 mil moisture vapor permeable plastic film coated
with a hypoallergenic, pressure sensitive adhesive. They are translucent material with very Good MVTR, high breathability and
Comfortness.
Fig 7: 3M incise tape 9948
13. Conclusion
Thermal comfort remains a major comfort factor in deciding of the fabric. Thermal comfort can be attained once when the
difference in outer temperature is in parallel to the microclimate created within the fabric. Various ventilation factors for the required
end application have to be predetermined clearly without fail because wrong usage leads to lag in comfortness.
Extensive research is required to understand the relationship between segmental ventilation and local comfort of the fabric
subjected to active usage of the person.
14. 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” , Journalof 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).

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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)
Holme, I., “Porous Polymers and Fusible Films”, J. Coated Fabrics15, 198–204 (1985).
Hae Wook Ahn, Chung Hee Park and Seung Eun Chung, “Waterproofand breathable properties of nanoweb applied
clothing”, Textile Research Journal 81(14) 1438–1447. (2011).
Roohollah Bagherzadeh, Masoud Latifi, Saeed Shaikhzadeh Najar1, Mohammad Amani Tehran, Mohsen Gorji and Lingxue
Kong, “Transport properties of multi-layer fabric based on electrospun nanofiber mats as a breathable barrier textile
material”, Textile Research Journal 82(1) 70–76. September 14, (2011).
Sanjay S. Chaudhari, Rupali S. Chitnis and Dr. Rekha Ramkrishnan, ”Waterproof Breathable Active Sports Wear Fabrics”,
(2010).
Apurba das and R.Alagiruswamy, “Science in clothing comfort”, Woodhead publications, ISBN 13:978-81-908001-5-0,
(2010).
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