25 Protective Textiles

S. Amsamani

1. INTRODUCTION

   The development in novel technology, need to explode the unseen or unknown and unpredicted climatic changes has increased unexpected hazards especially in work place to which humans are exposed. Hence protection measures have become the key for all industries and special work areas. The need for protection has paved way for researches and developments of protective clothing. The technical textile products under this category are fire retardant apparels and fabrics for furnishings, chemical protection clothing, high altitude clothing, ballistic protective clothing, bullet-proof jackets, high visibility clothing, radiation protection textile, protection industrial helmets and gloves. They are intended to protect the persons from extreme temperature environments, bullets, explosive, harmful chemical environment, low visibility and so on. Defense sector is one of the largest consumers of protective textiles. The protective textiles required in defense sector are bullet proof jackets, NBC suits, high altitude clothing and fire-retardant apparel. The worker’s safety practices, fire safety standards and increase in terrorist attacks create demand for protective products especially clothing.

1.1 LEARNING OBJECTIVES

At the end of the session the learner will be able to

•  Understand the significant role of protective textiles on the preservation of human life
•  Identify various types of protective textiles and their uses

2. DEFINITION

  Protective textile or Protech is a collection of various fiber, yarn or textile products, and garments exclusively manufactured to safe one from different type of climatically conditions and on the other side ease the working conditions and also to protect them from any type of miss happening. Protective textiles include products used to help the worker to complete his assigned job without much difficulty in hazardous environment and his clothing and accessories.

3. Classification of Protective Textiles

  All textile and clothing materials offers protection only the type and degree of protection differs. Climatically changes require textiles to protective one self. In case of rain a rain coat is used but during snow fall a fur jackets which is specially designed to shed off snow is required. This type of clothing is also protective textiles but the level of protection is low. Since these types of clothing and accessories are used in our day to day life the module concentrates on textiles used in special conditions like accidents and hazardous environments. Protective textiles can be classified based upon the usage, like clothing used in moderate climatically changes eg summer or winter clothing used in case of environments related to the extreme temperature changes, like clothing required at North Pole, mining areas, chemical industries which are specially designed for the comfort of the user.

These clothing can also be classified based on the duration of usage as products used for a short period like in case of fire accidents, the flame proof uniforms used be the firemen or items used for a longer period like glacier caps used during mountaineering. Another classification is based on the need of the product as protective textiles need for the survival at that particular point like nuclear, ballistic biological and chemical jackets or masks and products which ease the environment like gloves used by the farmers while spraying chemical manure.

3.1Types of Protective Textiles

Based on the need and end uses the types these products are generally made out of specific yarns, with special finishes. These products are covered under all three methods of fabric construction namely woven, nonwoven and knitting. In special cases the fibers are chemically made. Recent researches have given genetically modified fibers to upgrade protective textiles. Nano Technology also plays a very vital role in production protective textiles.

3.1.1 High Altitude Clothing

High altitude clothing or extreme cold climate clothing (ECC) is used for protecting from extreme weather conditions like high velocity winds, extreme low temperature and snow fall specifically in regions like the Everest. These clothing items are well supported with thermal protection devices which are mainly designed for preventing hypothermia, described as the ‘killer of the unprepared’. It is a condition that occurs when the heat lost from the body exceeds the heat gained through food, exercise and external sources.

The high-altitude clothing consists of glacier gloves, rappelling gloves, jacket, trousers, glacier cap and waist coat. The characteristics required for this type of clothing are resistance to quick wear and tear, hydrophilic, abrasion resistance, moderate weight and thickness, breathable and maintain high integrity. Mostly thermal insulation properties are incorporated in clothes which are used during work to protect the wearer in case of accidental or emergency immersions in cold water. The thermal conductive yarns are integrated with in the woven structure for clothing used by air lines workers and navy crew travelling to the polar regions. Special finishes for maintaining heat has been imparted to these types of clothes. Micro porous coatings can be made by mechanical fibrillation, solvent exchange, solvent extraction or phase separation. Lamination is another method of coating these fabrics. Specially designed flotation vests are also used during water sports. The properties of these coats are high resistance to tear and wear, abrasion, uv rays, water proof, light weight and breathability. Usually these garments are made with polymers and the given required finishes.

3.1.2 Survival Suits and Bags

Survival suits and bags are made from spun bonded polyolefin fiber after aluminized. In India high altitude suits named Suit Yeti, consists of three layers that conform to an extended cold weather clothing system. All the three different layers can be worn depending on the individual’s metabolic response to cold climate and weather conditions. The outermost garment consists of PTFE sandwiched between two layers of nylon fabric which acts as a breathable membrane. It is coated to give a fully windproof and waterproof garment. This helps to keep the inner shell’s thermal insulation intact though transmitting the moisture out wards. Wind stopper fleece is used to make the middle layer which is extremely breathable due to PTFE membrane that helps to transmit the body moisture from inner most layers to outer shell. This middle garment is capable  to achieve very high level thermal insulation. The innermost layer made up of knitted polypropylene terry pile fabric enables fast evaporation of sweat by wicking.

For the safety of these suits and easy transport they are packed and stored in special bags. The bags used are also made PVC coated with suitable solvents. The sizes and color of these bags vary. The handles of these bags are made out high quality double plain nylon. There is a small pocket or pouch attached to the sides of the bags to fix the name tags. It is made out of plastic. Some bags have provision to carry papers and some important personal belongs. The major properties of these bags are easy to handle, flexible, light weight, thin and resistance to water and fire.

3.1.2 Ballistic protection

Ballistic protection includes guarding the wearer’s body against fragments and projectiles of various size, shapes and impact velocity. The high tenacity, low density and high modulus of elasticity make them capable to absorb large amounts of energy. The ballistic protection clothing is made from natural fibres like silk to metallic fibres like steel. The commonly used fibres are nylon 6.6, glass fibre and aramid (Kevlar and Twaron), aromatic polyamide (Aramid) and Ultra High Modulus Polyethylene (UHMPE). High tenacity polyethylene fibre, are chiefly used to make Blast-proof vests. The outstanding elongation and elasticity of Aramid yarns gives them best resilience to ballistic impact properties. Multiple layers of woven fabric were used in traditional ballistic armour and bullet-resistant vests. The degree of protection is directly proportion to the number of layers. Neoprene coating is also commonly used. Plain square weaves are the most effective weave in ballistic protection.

The bullet-proof jackets made from Aramid, Nylon 66, or Carbon fibres weighs about 5 kilograms. The jackets should be comfortable to wear, able to spread the projectile energy efficiently, light weight and facilitate body movement. Needle punched nonwoven fabric made out of high performance polyolefin fibres and polyethylene is claimed to provide brilliant ballistic protection as well as outstanding protection against sharp fragments by absorbing projectile energy and deformation along with low density, light weight and thin construction.

Very low mass per unit area felts are most effective materials, but, as the mass increases, the woven textiles stand superior to felts in performance. The key manufacturers of bullet-proof jacket in India are Tata Advanced Material Limited (TAML) – Southern Group of Industries Pvt. Limited and Isolar India for Glass based bullet-proof jackets.

3.1.3 Fire Protection Textiles

Textiles themselves are flammable material and can turn into prime source of fire in case of break-out. Flame and heat resistant textiles which are chiefly used to protect fire should prevent fire, flammability, melt, heat conduction and should not emit toxic fumes. This kind of textiles are largely used by firefighting personnel, offshore oil and gas ring workers and in airlines, ship, railways, office furnishings, hospitals and cinema multiplex The two major classes of fire retardant fabrics are natural fire retardant fabrics like glass and fire retardant coated fabrics. The inherently permanent fire retardant fibres are modified polyester fibre.

Fabric woven with inherently non-combustible glass fibre coated with exclusive water-based polymers is having the characteristics such as, it does not melt, ignite, rot, drip, stretch or shrink. It is also distinguished for its low level toxicity of smoke emissions. Hence it is used during the manufacture of fire and smoke proof curtains in ship, furniture barriers and cargo wraps in air crafts.

Aramid (meta and para), modacrylic and polyamide are the other fire-retardant fabrics.

The ideal features of the fire-retardant fabric are:

•  High tear and abrasion resistance
•  High dimensional stability
•  Anti-decay and Anti mould
•  Breathable and comfortable
•  Very low fume toxicity in fire
•  Crease resistance
•  No fading and excellent colour tone

Trevira® a Reliance Netherlands B.V. brand is the world leader in fire retardant fabric. Manufacturers of chemical coated fire-retardant fabrics in India are Rajasthan Weaving and Spinning Mills Limited and Jaya Shree Textile.

3.2 Exposure to hazardous environments

Exposure to hazardous environment comprises the long-term exposure to milder conditions that is not normally associated with disasters or accidents. This includes rain, foul weather, wind, extreme cold, high temperatures, nuclear reagents, molten metal splashes, chemical reagents, microbes and dust. Normally modified polyester high performance fibers are used. In some cases even natural fiber like silk blends, wool and glass fibers are also used. These fabrics have woven knitted or non woven structures. The fabrics are usually coated with suitable solvents to resist the hazards conditions.

3.2.1 High-Visibility Clothing

High visibility clothes or Reflective-wear is essential for protecting people working in poorly light workplace like mines, airport runways and high ways. The photo luminescent materials absorb artificial light and emit green-yellow light in the darkness. There are generally three types of high visibility clothing:

•  Photo luminescent material which give yellow light in dark
•  Reflection materials which shine when struck by light
•  Fluorescent material which is more visible even during the day

   Non-radioactive and non-toxic Zinc Sulphide crystals are used. Fluorescent materials have the ability to convert non-visible UV ray’s energy into visible energy which is useful during daylight. There are two types of high visibility clothing such as suits with plastic tapes and suits with glass beads or retro-reflective tapes, which give visibility up to 600 meters. The technology encompasses of coating highly reflective glass beads with a density of 50,000 tiny glass beads per square inch light.

The characteristics required for ideal high visibility apparel are day and night visibility, light weight, permeability to air and moisture, comfort, universal one-size-fits-all design features, durability and neatness with finished edges. The fabric used for making high visibility clothing is normally fluorescent polyester tricot fabric with 120 GSM with reflective micro sheeting. The typical width of reflective tapes is 5 cm. The fabrics used to manufacture high visibility clothing are imported from China and Korea.

3.2.2 Chemical Protection Clothing

Chemical Protective Clothing (CPC) is used for protecting the whole body from toxic chemicals and physical hazards. The chemicals can be absorbed into the human body either by physical contact or by inhaling, hence chemical protective clothes are specially designed to prevent the physical contact of toxic substances. The chemical protective clothing suits can be of durable type made out of non-permeable textile fabrics such as rubber/ PVC coated fabrics which block the penetration of the chemicals through the fabrics. It is an effective method, but it does not permit moisture and air too thus it leads to stress rather it becomes a non breathable fabric. The next category is air and moisture permeable disposable type made out of non-woven fabric and can be used only for 3-4 times.

Carbon-containing materials were also developed. It includes carbon-impregnated polyurethane foam, carbon-coated nonwoven fabric, activated charcoal cloth and hard carbon microsphere-adhered woven fabric. Durable type chemical protective clothing is having good demand in India. Cotton or polyester cotton base fabric coated with PVC is used in India. The chemical protective clothing is used by workers engaged in petroleum, dyes, paints, chemicals and chemicals products industries.

3.2.3 Industrial gloves

Industrial gloves serve as an item of protective accessories. Cushioning and protection for hand from blows in heavy-duty work for workers in factories, iron and steel industry, welding applications, oil refineries, construction, pharmaceuticals and chemical industries can be obtained from industrial hand gloves. It protects the hands from sparks, heat and rough objects.

 They are classified under thermal protection as well as cut-slash protection. Gloves are made out from cotton, asbestos, variety of leather, Spectra and Kevlar (Para-aramid). The construction methods of gloves vary as construction of leather, knitted, non-latex (nitrile) and rubber or latex gloves. They are also available in varying gauges or sizes.

The characteristics required for gloves are comfortable and durable, mild heat resistance, protection against cut and hot splash, high abrasion protection and better grip with anti-slip coating. Aramid gloves have temperature tolerance from 250 to 750 centigrade and nitrile gloves provide chemical splash protection.

The leading manufacturers of industrial gloves are Mallcom India Limited, Rajda Industries and Exports Pvt. Limited, Lumens India and KDM Impex Pvt.

3.2.4 Industrial Helmets

Industrial helmets are being used for protecting head from exposure to hazardous environments at work places like mines or chemical industries. It consists of two layers, the inner layer made up of polypropylene or foam and an outer layer made out of steel fibres. Its primary function is to protect the skull and brain injury. The two kinds of helmets available are Full face helmet and Open face helmet. The full face helmets have glass or plastic transparent cover across the face so as to enable the wearer to view. It is used while working in under water units, mines, chemical industries and welding units where the workers has more chances of coming in contact with fire or poisonous chemicals and gases. In some helmets provision for light emission in the form of torches are attached at the top to enable the wearer to see his surrounding and work with both his hands. The helmets are bounded to the wearers head by means of a strip of fabrics which is made up of nylon 66 or polyester and its blends. Mostly these strips are braided.

4. CONCLUSION

Along with the development of technology it is essential to provide safe and protective work environment. The new inventions in textile science has offered numerous multifunctional materials designed with specialized spun yarns or bonded fabrics finished with novel solvents to  provide protection against specific conditions such as extreme cold climate, war, heat, high darkness, biological and industrial harshness. Great care and advance technology has been put in developing protective wear which enable more efficient work from men and thus increasing productivity.

Web links

• www.apparelsearch.com/definitions/clothing/protective_clothing.htm
• https://en.wikipedia.org/wiki/Personal_protective_equipment
• www.honeywellsafety.com/USA/Product_Catalog/Protective_Clothing.aspx
• www.dupont.co.in/…protective…protective…/industrial-protective-clothing.html
• www.ist.com.tr/[phone]
• https://www.bsigroup.com/en-IN/Our-services/…Protective…/Protective-Clothing/
• www.about.com/Chemical+Protective+Clothing