Technical Textiles – A Vision of Future

In most of the developed countries, technical textiles already account for 4% of the total textile production. Even in many developing countries, the proportion is well above 10%. At present, India's contribution in this area is negligible at about 0.2%.However, due to competition from neighboring countries ad emerging economic power, India has tremendous potential for production, Consumption and export of technical textile. In the circumstances, textiles are playing major role through its diversified applications and undoubtedly the future of this technical textiles appears tom be bright in this, lot of uses are there. They are medical textiles, protective textiles, agricultural textiles, geo textiles, automotive textiles, smart textiles and industrial textiles.

1. INTRODUCTION

Technical textiles are the textiles in which more technical are involved. It has lot of advantageous in all sides. Among these, we explained about agro textiles, automotive textiles, geo textiles, medical textiles, protective textiles, smart textiles.

2. AGROTEXTILES

With the continuous increase in population worldwide, stress on agricultural crops has increased. In order to keep grains, vegetables and flowers, it is necessary to increase the yield and quality of agro- products. However, it is not possible to meet fully with the rationally adopted ways of using pesticides and herbicides. Further, methods are expensive and have long lasting ecological impact on soil as well as delivered product. Today, agriculture, horticulture area has realised the need of tomorrow and opting for various technologies to get higher overall yield, quality and tasty agro products. Adopting the hi-tech farming technique, where textile structures are used, could enhance quality and overall yield of agro-products. Textile structures in various forms are used in shade house/ poly house, green house and also in open fields to control environmental factors like, temperature, water and humidity. It also poly avoids agro products damage from wind, rain and birds. Agro textiles like sunscreen, bird net windshield, mulch mat, hail protection net, harvesting net, etc can be used for achieving the above goal.

2.1. Products

Wide varieties of agro textile products are available and the selection of suitable type of product depends on the protection that the crop-Selection of the agro textile is greatly influenced by the geographical location. At some location agro textiles are used to protect the plantation from excessive sunlight while at some places it is expected to protect plant from cold. Therefore selection of agro textile is done as per the location and the desired protection from the external agencies. With the use of high quality agro textile quality and yield of agro products can be enhanced. Some of the agro textiles explained are:

4.4.5. SMART CLOTHES

F A C Fashion and Design, Germany has developed smart clothes that have some excellent characteristics like rounded lines, new pocket shapes, rounded zippers, smart reflective logo, natural soft lettering , and topstitching integrated in solar cell. These smart clothes have wearable electronics as integral part of the garment, mobile, recorder and global positioning GPS systems.

4.4.6 SPORTS JACKET

A Philips Research laboratory has developed material with conductivity that changes in a predictable why as it is stretched. They made a sport jacket that can sense the arm movements of the wearer. Sport jacket could be used to monitor and assist people when playing sports.

7.2. EXTREME COLD

Cold protection requires products with high degrees of insulation, the least bulk, good/relative comfort, and still allowing good dexterity for doing useful work. Still air is a poor conductor of heat, so insulation requires a layer of still air between the skin the source of the heat or cold.

7.3. BALLISTIC PROTECTIVE MATERIALS

Most military casualties which are due to high speed ballistic projectiles are not caused by bullets. The main threat is from fragmenting devices. In combat, this means in particular grenades, mortars, artillery shells, mines, and improvised explosive devises used by the terrorists. There may also be casualties from the secondary effects of bombs including collapsing buildings, exploding air craft, sinking ships and flying debris.

Shield technology lays the parallel strands of synthetic fibres side -by-side and holds them in place with a thermoplastic resin, creating a unidirectional tape. Two layers of the tape are then cross - plied at right angles (0 or 90) and fused in to a composite structure under heat and pressure. The cross plied unidirectional panels are then pre consolidated into rolls, which are used to make the finished products.

7.3.1. Chemical Protection

Protective clothing is used for chemical production is categorized from high to low, level A -D. fabrics containing electrometric barriers such as butyl rubber provide excellent protection from chemical warfare agents, but wearers can use the clothing only intermittently due to rapid on set of heat stress, motion restriction, and weight. These fabric systems are heavy bulky and subject the soldiers to heat stress under high workload and battlefield conditions.

4.4.2. MUSICAL JACKETS

4.4.3. INTELLIGENT WEAR (I - WEAR)

I-clothes composed of six technical layers, each with a specific function. The team of star lab developed a wireless communication system and fabric area network to permit networking of sensors and data on clothing. This wireless network allows communication between the various layers, without danger of radiation to the body. The network is integrated in a natural and flexible manner into the fabrics.

4.4.4. Data wear

Data wear incorporates sensors at each of the body joints plotting the position on a graph, which is calculated on a computer. The sensors are made from conductive elastane. Data wear clothes consists a bunch of magnetic position sensors, the TCAS system measures the angle of each of the joints to determine absolute position of each of the limbs. It has been designed for comfort and ease. The sensors can be places to specification for individual applications. The Datawear body unit consists of jacket, trousers and gloves that are circuited or wired electronically for interaction with computer. The application of Datawear is to track position of limbs in computer data, medical imaging, measurement, ergonomics, biomechanics, robotics and animation. The whole body can be monitored by Datawear, which has a particular relevance in fields of sports injuries and biomechanics.

4.5. WEARABLE COMPUTER

Boeing Computer Services, Honeywell IND, Virtual Vision, Carnegie Mellon University and some other research organizations are developing a wearable computer system that is better powered computer system worn on the user's body ( on a belt, backpack or vest) Wearable Computer is designed for mobile and predominately hands free operations, head mounted displays and speech input.

MEDICAL TEXTILES

Nowadays in medicals also textiles is used in many ways. It is divided as follows;

5.1. IMPLANTABLE MEDICAL TEXTILES:

The materials are used in effecting repair to the body whether it is wound closure (sutures) or replacements Surgery like vascular grafts, artificial ligaments, etc). There are many shapes and sizes, for duplications as found in human body. Filament, textures yarns used nowadays, which are coated to prevent leakage of blood while tissue, is forming on the inner walls.

.Carbon fibre is a popular material for tissue repair.

.Suspensors and reinforcing surgical meshes are used in plastic surgery for repairing defects of the abdominal wall. Surgical treatments of hermia in Urology etc.

.Hydrophobic snivels felt dressings are high porosity textiles made from man- made fibres designed for treatment of bums and different dermatological defects.

5.2 NON - IMPLANTABLE MATERIALS:

These materials are used for external applications on the body and may or may not contact with skin. They are made form co-polymer of two amino acids. They are employed as covering, absorbent, protective and supports for injured or diseased part. They are different types.

5.3. PRIMARY WOUND DRESSINGS:

Placed next to the wound surface. Nonwoven with a binder content of 60% and made from cellulose fabrics are being used.

5.3.1. Absorbent:

Similar to wound pads used in surgery, manufactured from well-bleached, carded and cleaned cotton fabrics.

5.3.2. Bandages:

These are narrow cotton or linen, plain weave cloth of low texture, either woven or knitted. Ex: Plaster of Paris Bandage, orthopedics bandage, crepe Bandage.

5.3.3. Protective eye pad:

Scientifically shaped 2 " x2 x to lit over the eye used in outpatient clinic and industrial medical department.

5.3.4. Adhesive tapes:

It is narrow, plain weave fabric having a coating of adhesive paste. It is used with other pads to conform them to the injury.

5.4. EXTRA CORPOREAL DEVICES:

Extra corporal devices are mechanical organs that are used for blood purification and include the artificial kidney, the artificial liver and the mechanical lung.

5.4.1. ARTIFICIAL KIDNEY:

.Tiny instrument, about the size of a two - cell flashlight.

.Made with hollow hair sized cellulose fibres or hollow polyester fibre slightly latest than capillary vessels.

.Fabric which is used to remove waste products from patient's blood.

5.4.2. ARTIFICIAL LIVER:

Made with hollow viscose to separate and dispose patient's plasma and supply fresh plasma.

5.4.3. ARTIFICIAL HEART:

.An 8 - ounce plastic pump lined with dacom velour to reduce damage to blood and is a chambered apparatus about the size of a human heart.

.Silastic backing makes the fabric imperious to emerging gas that is not desirable in the blood.

5.4.4. MECHANICAL LUNG:

.Made with hollow polypropylene fibre or a hollow silicone membrane.

.Used to remove carbon-di-oxide from patient's blood and supply fresh oxygen. Health care textiles

5.5. PRODUCTS USED FOR MEDICAL SURGICAL DRESSINGS

The modern wound dressing is usually made of three layers-

a.Wound contact layer: - It should not stick to the wound or cause maceration of the skin if the dressing is not changed. It can be woven, knitted or non-woven made from silk, viscose, polyamide or polyethylene.

b.Middle absorbing layer: - If has to absorb blood or liquids while providing a cushioning effect to protect the wound. It is generally a non-woven composed of cotton or viscose.

c.Base Material: It provides a means by which the dressing is applied to the wound. The material is coated with acrylic adhesive to hold the dressing in place, eliminates the need for bandage.

5.6. BANDAGES:

Bandages are designed to perform a whole variety of specific functions depending upon the final medical requirement. They can be woven, knitted, non - woven or composite in structure. They can be classified into various classes depending upon the function they serve as.

a)Simple bandages - It is an open weave cotton or viscose fabric cut into strips which have been scoured, bleached and sterilized. The problems of fraying in the plain woven bandage are overcome by use of non-fraying cotton leno bandage. The structure of bandage is more stable with crossing warp threads in the leno woven structures. These can be further coated with paraffin to prevent sticking of the bandage to the wound. Further some ointment dressing can also be given along with paraffin to aid faster healing of the wound. Elasticated yarns are incorporated into bandages to form elastic bandage for providing support and comfort.

b)Light support bandages - Woven light support bandages are used for sprains or strains. Elastic crepe bandages are used for sprained wrist or ankle support. The elasticized properties of these bandages are obtained by weaving cotton crepe yarns that have twist content. Stretch and recovery properties of these bandages apply sufficient tension to support the sprained limb.

c)Compression bandages - Compression bandages are used to exert a certain compression for the treatment and prevention of deep vein thrombosis, leg ulceration and varicose veins. Depending upon the compression they provide, compression bandages are classified as light, moderate, high and extra - high compression bandages. They can be woven

Warp or weft knitted from cotton and electrometric yarns.

d)Orthopedic bandages - These bandages are used under plaster casts and compression bandages to provide padding and prevent discomfort. Non - woven orthopaedic cushion bandages are made from polyester or polypropylene and blends of natural and synthetic fibres. Polyurethane foam can also be used. Light needle punching gives bulk and left to the structure for greater cushioning effect.

5.7. PLASTER:

Plasters are made up of three layers - 1) Plaster fabrics, 2) adhesive and 3) - wound pad. A simple plaster cast consists of gauze impregnated with plaster of Paris. The modern plaster fabric is made from spun bonded nonwovens of cotton, viscose, polyester or glass fibre. The adhesive used for plaster fabric is acrylic that doesn't stick to the skin. The cushioning wound pad is made from knitted viscose fabric impregnated with an antiseptic. The highly absorbent wound pad helps in rapid absorption of secretion from the wound.

6. GEOTEXTILES

Geo textiles have been defined as woven or non woven fabrics having application in civil engineering, such as, interfacing of fabrics with soils to give reinforced structures or enhancing hydraulic properties of water transport.

6.1. USES OF GEO TEXTILES

6.1.1. FILTRATION

Filtration is one of the functions most widely performed by geo textiles. The filtration function has two concurrent objectives: to retain the particles of the filtered soil, while permitting water to pass through the plane of the geotextile from the filtered soil. These two parallel roles are the key to filtration design (Figure).

Geotextile in roads

Geonet made of polypropylene with following specifications are capable of withstanding high temperature and are suitable for Asphalt reinforcement. The Geonet are non-corrodible, inert to chemical attack, non-biodegradable and thermally stable. They are available in a width up to 10 meters and suitable roll length. The aggregate in the overlay gets interlocked in the mesh openings and a stiff layer is formed at the interface of base layer and overlay. This system prevents further propagation of cracks.

Advantages

.Control reflection cracking in overlays.

.Increases fatigue life

.Improved load distribution

6.1.2. DRAINAGE

The drainage function of geo textile involves transmission of liquid in the plane of fabric without soil loss. The major difference between filtration and drainage function is the direction of flow which makes in-plane permeability critical for drainage function. Nonwoven geo textiles can assist in the collection and removal of this potentially damaging water. Geo textiles used at the native soil/aggregate interface also protect the drainage system from contamination by soil fines, while permitting the free flow of water. Composite geo textile material allows water flow within the plane of the material, rather than across it, such as behind a retaining wall.

6.1.3. EROSION CONTROL

Riverbanks and coastlines can be undermined and damaged by wave or tidal action. The defensive elements that require protection are:

.The in-situ soil

.The filter unit protecting the soil

.The rock armour protecting the filter

The hydraulic and filtration properties of geo textiles allow them to be used in place of some of the traditional filter layers. Consequently, a single layer of geotextile fabric can replace a succession of stone filter layers. A single bedding layer of stone is laid on the geotextile, to carry the rocks that resist the movements caused by the hydraulic forces.

Other benefits include

.Geotextiles have built-in, factory-controlled filter properties

.Working underwater is much easier because the filter system can be assembled above the water and lowered into position

.Less time lost through bad weather or difficult water condition

6.1.4. ROCKFALL PROTECTION

Hill slopes composed of rocks are prone to generate rock fall and rock side hazards. Falling rock are highly dangerous to life and property because of large momentum they acquire during rolling and bouncing motion.

Solution

Use a high strength net very close to the surface profile with anchor behind the crest of the cutting and at the toe rock face. The vertical section will also have anchoring as far as possible with split bolts of capacity 3000 kg. Split bolts of 600 kg. Capacity will also be used as required by rock profile to stitch the net and to ensure that contour profile is followed to the best extent possible. The net is thus under reasonable tension and exerts a compression or inward force holding the loose mass together and prevents from easily getting disturbed due to surface movement of water, movement of fines and any untoward disturbance caused by vibrations.

6.1.5. COASTAL PROTECTION-GABIONS

Generally angular stones are preferred for dissipation of current and wave energy in hydraulic applications. However, based on wave surge and water depth, the stone sizes may become too large for convenient handling

.Sunscreens
.Bird protection net
.Plant net
.Harvesting net
.Windshield
.Root ball nets
.Turf Protection Net
.Mulch mat
.Nets for covering pallets
.Packing materials for agricultural products

SCREEN

In order to protect fields and greenhouses from the intense solar radiation for healthily plant growth and good harvest, sunscreen nets with open mesh construction are used to control sunshine and amount of shade required. Sunscreen fabrics are available with different shade coefficient like 35% 50% 65% 95%. These net fabrics allow the airflow freely, so the excess heat does not built up under the sunscreen.

Use of Gabions holding the small boulders together offer the ideal solution of coastal protection. Gabions are sausages made of polypropylene twisted ropes are appropriately woven by a special process to fabricate in various sizes. Gabions are generally available in prefabricated collapsible form with a bottom and four sides held together by appropriate binding and with a flip open top lid. The border rope is of 10mm/12mm size and body rope is of 10mm/8mm/6mm. The sizes are selected depending on the severity of the problem and the method of installations to be adopted.

Advantages of Polymer Gabions

.Resistance to acidic and alkaline environments. Immune to rot, mildew, marine organisms.
.Flexible and can easily take the riverbed contour.
.No rusting and no damage to fishes.
.No effect of water, non-biodegradable.
.High tensile strength, High abrasion resistance, High thermal stability.
.Resistance to U.V. degradation.
.Can be lifted with cranes. Suitable for underwater construction.

Apart from this there are various other applications in railways, airport runways, reservoirs and also for taking blasting impacts.

PROTECTIVE TEXTILES
A market that is receptive to new products and suppliers and abounding with niche markets. The environment is consider to have the highest priority where protection of individual is considered un the defense application such as rain, snow, fog, wind, lighting, sun light, dust and also it should have to survive the intense heat, cold, wetness, UV light, wind-chill and other discomforts on land, sea and in the air.

7.1. PROTECTIVE CLOTHING COMPILATION

.Productive clothing can be divided in to the following groups:
.Clothing against heat and flame
.Clothing against mechanical impacts
.Fire men's protective clothing
.Clothing against cold
.Clothing against foul weather(moisture wind)
.Clothing against chemical substances (gas liquids, particles)
.Clothing against radio active contamination

7.3.2. Biological Protection

Biological protection comes in two categories. The first is the protection of humans and earth from harm. It usually involves stopping disease (or other kind of damages) from either natural sources or human cause accidents. The second is protection of potential new alien life forms from harm. It involves stopping humans from damaging alien life in space.

7.3.3. ADVANCED EOD BOMB SUIT AND HELMET

An advanced design bomb suit and helmet that offers highest ballistic protection in the world. The suit is constructed from Kevlar with an outer anti static cover of 50/50 Nomex/Kevlar and comprises of a jacket, crotch-less trousers, groin cup and rigid ballistic panels. The suit itself is light weight in comparison with other suits, with frond protection plates and this maneuverability reduces operator fatigue and increases operator effectiveness.

7.3.4. NBC LIGHTWEIGHT OVERBOOT

Lighter then all existing ECW boots within its category, the boot has a polyester shell with a moisture vapour permeable (MVP) barrier layer, assuring water resistance, good breathability and dryness in all weather conditions.

Microtherm has been one of the leading high temperature thermal insulation materials. It is a better insulation even than still air and at high temperatures has a thermal conductivity as much as four times lowers than most conventional insulations such as fibre. Microtherm products cover a comprehensive range in both rigid and flexible forms, facilitating neat and effective design solutions to the many diverse thermal problems that can be encountered in military equipments.

7.4. CONCLUSION

The technical textile market is respective to innovative new products. There is opportunity and need for functional, cost-effective materials. But the market is fragmented and complex. Development and lead times are often long and expensive. The market is quite small but exhibits moderately strong growth and produces are generally of high unit values. Due to increasing health and safety issues at work this may be an increasingly attractive segment. Good products are needed and they must work well. It is a market that offers opportunity, but also one that demands that much development and testing be done prior to adopting new products. There may be long lead times much resistance to things new products to market. The truth is, we can not afford not to have the ideas and products

7.5. REFERENCE

.Smart fibres, fabrics and clothing; Xiaoming Tao, Wood Head publishing.
.Synthetic fibre materials; H.Brody, polymer science and technology series.
.New fibres; second Edition, tatsuya Hongu
.Technical textiles -NCUTE
.Textiles in automotive engineering; walter fung &mike hard castle, wood head publishing
.www.textiles.edu
.www.textilesinfo.com
.Geo synthetics , J. k. Mandrel
.High performance fibres; JWS Hearle,Wood Head publishing.

About the author:

Mr. Gopalakrishnan is doing his Diploma in Home Textile Management. He did hisDiploma in Textile Technology & B.Tech in Textile Technology from PSG College of Technology & Polytechnic College. After his diploma he worked as a Production & maintenance Supervisor in Cambodia Mills (NTC) Coimbatore, after three years of experience he came back to his B.Tech.He did 17 paper presentation in various technical symposiums, national & international confrences in all over india and participated in various technical workshops & innovative project works. He published several articles in journals, magazines.

Area of Interest: innovative textiles, Technical textiles

Email dgk_psgtech@yahoo.co.in

To read more articles on Textile, Fashion, Apparel, Technology, Retail and General please visit www.fibre2fashion.com/industry-article

2.3. BIRD PROTECTION NET

Open -mesh net fabrics are used as a means of protecting fruit plantation crops and vegetables from flocks of birds. Plantation area is covered from top and side to stop the birds from getting into the fields. The advantage of using pets as a cover other means of protection is that the nets only have to be erected once in the season.

2.4. PLANT NET

Fruits, which grow close to the ground, can be kept away from the damp soil by allowing them to grow through vertical or tiered nets in order to keep the amount of decayed fruit to a minimum.

2.5. HARVESTING NET

Harvesting nets are extremely helpful to those countries where labour charges are costlier. With the application of such nets for harvesting purpose the labour cost could be reduced considerably. They are laid on ground or tied under the tree so that fruits fall directly on to them.

In Windshields are used in forming to protect fruit plantation from wind this way hard as well as soft fruits can be harvested with minimum proportion of is not damage and to prevent damage to plants. It also prevents plants being cooled by the wind. These measures create favorable climate condition for growth and improve harvest yields. Windshields can have large or small openings depending on the amount of wind protection required.

2.6. ROOT BALL NET

For safe and speed growing of young plants it is extremely important that root system is not damaged when they are dug up, transported or replanted. Normally the root balls are wrapped in cloth. Elastic netting tubes are an effective alternative to this. The soil and root system are held together by gentle pressure from the elastic yarns surrounding them, so that root balls and the earth sticking to them can be transported safely. When the plants are transported the nets on the outside do not have to be removed since the roots can protrude through the nets. Particulars advantage of tubular net wrapping is the ease of handle.

2.7. TRUF PROTECTION NET

Nets are put over the grassy areas on riverbanks. Dykes, etc so that lumps of earth are not removed while animals are grazing them. This will help in minimizing soil erosion loss and improve conservation.

2.8. MULCH MAT

Mulch mats are used to suppress weed growth in horticulture applications. Mulch mat covers the soil blocking out light and preventing the competitive weed growth around seedlings. This also reduces the need for herbicides required for weed control. Needle punched non-woven and black plastic sheet are used for this application, Biodegradable and non-biodegradable type or mulch mats are available.

2.9. NETS FOR COVERING PALLETS

For safe transportation of fruits and vegetable to the market individual boxes are collected into larger units and these boxes are covered with wide, large mesh nets on pallets to stop the boxes being turned upside down or squashing each other. This prevents damage to goods during transportation.

2.9.1. PACKING MATERIALS FOR AGRICULTURAL PRODUCTS

Nets can be used in the form of sacks, bags and tubes for packaging of farm products for many end uses. If includes:

.Packing sacks for vegetables.
.Tubular packing nets for fruits

Net structures are preferred because of their high strength, low weight transparency, air permeability and cheapness. The pressure exerted on soft fruits is very less because of the use of flat tape yarns. Desired open-mesh structure can be produced.

3. AUTOMOTIVE TEXTILES

The growth of automotive textiles is very good in lost decades. There are few driving forces behind the growth of automotive textiles. These forces could be

.Improvement in the standard of living of people resulting in the greater demand for personal vehicles.

.A car interior has become more and more important as people are spending more time in cars.

.For better fuel economy the trend is towards light weight vehicles replacing metal by fibre composites in most of the applications.

.Stringent legislations led to more safety devices in the vehicles in the form of air bags and seat belts.

.Eco logical reforms for recycling of used cars have increased the amount of textiles in an automobile.

.Apart from interiors and safety, textiles have also come up with the solution to engineering problems such as tyre reinforcement, acoustics protection, gas and air filtration.

3.1. CAR INTERIORS

People are spending more time in car due to increased traffic density, greater mobility and long distance traveling. Car interiors becoming increasingly important with raised consumer expectations. Car interiors comfort is an important priority reflecting in their costs of car interiors.

Today, over 90% car seat covers are made of polyester filament yarns. Apart from good abrasion resistance and UV resistance, polyester also offers good tearing strength, ease of cleaning, mildew resistance. Wool is sometimes used due to its flame resistant characteristics but it is only limited to upper end cars. Polypropylene is also striving to capture market but it is associated with certain inherent drawbacks such as lack of dyeability, low thermal and abrasion resistance.

3.2. SEAT BELTS

Wearing of seat belt can reduce fatal and serious injuries by 50%. All new cars in western countries have diagonal seat belts made of 250 grams of fabrics. Seat belt is an energy absorbing device, which controls the forward movement of wearer in an event of sudden deceleration of vehicle. Seat belt is designed to keep the load imposed on victim's body during crash, down to survivable limits and deliver non recoverable extension in an event of crash. This non recoverable extension prevents the occupant from being pulled back into their seats and sustains whiplash injuries soon after the impact.

Today in modern cars seat belts are designed to hold the occupants in correct position to strike air bag then it is inflated. Thus in modern car seat belts and the air bags are not substitute to each other but complementary. Due to non recoverable stretch the seat belts has to be replaced after major accidents.

Polyester is the most preferred fibre for seat belts as it satisfies the requirements of maximum extension upto 24 to 30%, good abrasion resistance, heat and light resistance and light weight. About 90% seat belts are made from polyester only.

Basically, seat belts are narrow fabrics (mostly 46 mm) from polyester filaments. They can either be formed spun dyed yarns or piece dyed.

3.3. AIR BAGS

In most countries air bags are mandatory for all passenger cars due to stringent in legislation. In 2002 alone, air bags system has contributed up to 20% reduction in fertilities resulting from front collision. Earlier air bags were considered as substitute to seat belts and were only limited up to high speed sports cars. But today, air bags are working in coordination with seat belts. In fact, air bags cushion an occupant in an event of crash. This helps in avoiding the heat on collision.

The working of air bag is precision application. In just 0.03 seconds air bags should begin and by 0.06 seconds after crash bag should be fully inflated. Air bag may build into stearing or in some other strategic location. Mostly, nitrogen gas is used in air bags.

Fabrics used for air bags must be able to withstand force of hot gases and they must not penetrate through fabric. Air bags are typically oven from HT multifilament nylon 6.6. Nowadays, one piece weaving system, produces air bag directly on loom. But earlier it was two piece seen together with suitable threads. Also research is going on to use nonwoven for this end use. Air bags can be coated or uncoated. Typically, front air bags are uncoated. Size of air bags may vary according to position.

3.4. CARPETS

There is about 3.5 to 4.5 sq. mts. carpet in each car. Apart from ethical and sensual comfort, carpets also play significant role in acoustic and vibration control. Increasing popularity of multi purpose vehicles and headliner carpets had also increased the demand of the same.

Road noise is considered as an environmental pollution in few countries. There are pressures on automobiles to reduce external noise about 50%. Carpets are contributing to solve this problem. Carpets by providing thermal and acoustic protection, thus directly contributing to safety.

3.5. TYRE CORD FABRICS

Tyre cord fabric is skeleton structure, which holds the uniform rubber mass of tyre. Tyre cord fabric has a tyre reinforcement performs to basis functions:

.It gives dimensional stability to tyre. Tyre is a pressure vessel and cord fabric keeps it dimensionally stable.
.
.Cord fabric also gives skeleton stage, fatigue and braises resistance, load carrying capacity.

Mainly polyester, nylon, HT rayon and Kevlar is used in tyre cord. Warp consists of any of above yarn (300 to 500 tex) with very few weft threads 1 to 2 ppi of 15 to 25 decitex. The main purpose of weft thread is only to keep warp threads together. Single yarns are twisted about 300 to 500 tpm and then doubled with same twist level but in opposite direction. Weaving is mostly carried out on heavy shuttle looms; projectile or rapier looms without temples with batching motion.

4. SMART TEXTILES

Some active smart fibres contain electric conductive materials, Phase Change Materials (PCM), and graphite particles, which can conduct electricity. In this way the resistance of the fibre is changeable along with the change of the fibre temperature due to change of fibre volume. As the materials warms, it expands and reduce conductivity between graphic particles. These materials can automatically regulate the on/off of the electricity and keep the temperature stable. PCM microcapsule was developed for US space travel agencies. In the production process, PCM is introduced into the textile fibre matrix in microcapsule form. These capsules prevent temperature variations by discontinuing temperature increase when the so-called phase change temperature is reached. The continuous energy fed from environment or from human body to PCM is soared in it, increasing its thermal capacity. Inversely PCM materials give up their stored heat again as the environment cools down. Paraffin's in particular find use for this function in the textile section.

The thermo catch heat insulation system developed by Mitsubishi Rayon with acrylic fibres contains the fibre core fine ceramic particles which convert light into heat, and with an antimony/stannic oxide component in the fibre sheath. Such bicomponent yarn was used in Mobile-thermo' snow jacket with an integral heating system inside the garment which assured precise temperature control, that snow jacket was worn during 1995 winter Olympics by members of Swiss team and 300 media persons in Nagano Japan.

4.1. SHAPE MEMORY MATERIALS

Shape memory materials are materials that are stable at two or more temperature states. In these different temperature states, they have the potential to be different shapes. When their transformation temperature have been reached. Shape memory polymers (SMP) are materials that have hard segments and soft segments e.g. polyurethane, polyester ether styrene- butadiene copolymer.

This is because the shape - memory materials exhibit some novel performance such as sensitivity, actuation, damping and adaptive response to external stimuli such as temperature, lighting stress and field, which can be utilized in various ways in smart systems.

Shape memory alloy wire and shape memory polymer films are already finding application in clothing. UKs Defense Clothing and Textile Agency is designing garment with these materials to protect wearers against heat or cold- Cold protection in leisure wear is usually achieved by laminating a layer of insulation material, consequently, the wearer needs to select the appropriate garment for facing weather conditions. A garment having variable insulation would have greater versatility and this could be achieved by using a composite firm of shape memory polymer as inter- liner.

The use of shape memory alloy in multiple layer fabric systems that change shape within a certain temperature range can be utilized to change the density between the individual layers. When temperature rises, an additional layer of insulating air is formed to enhance protection against heat.

4.2. TEMPERATURE SENSITIVE FABRIC

SWAY was multicolor fabric, basic 4 colors and combined 64 colours. SWAY can reversibly change color at temperature greater than 50C and is operable from-40 to 80oC. The change of color with temperature of these fabrics is designed to match the application, e.g. for ski-wear 11-190C, women's clothing 13-220C temperature shades 24-320C.

They developed an efficient, inexpensive method of attaching chromophores to the surface of polymers specially polyaniline. Polyprol, ploythiopene, and poly (ethylenedixoythiphene)

4.3. HEAT STORAGE TEXTILES

The main object of heat storage or thermal regulatory textiles is to maintain the wearer in a state of thermo physiological comfort under the widest possible range of workloads and ambient conditions. Heat storage and thermo regulated textiles are novel comfort textiles that can absorb, redistribute and release heat by phase change in low melting point materials, according to change in surrounding temperature. National Aeronautics and space Administration (NASA) planned to put the PCMs into gloves to keep pilot's hand warm. NASA developed textiles that aimed to improve the protection of instruments and astronauts against extreme fluctuations in temperature in space on the basis of heat absorbing and temperature regulating technology. It is very difficult to produce the composite fibre by melt spinning only using PCMs as one component because melt viscosity of textile grade PCMs remains lower than required. They do not posses the required spin ability. After mixing PCMs with PEG of sufficient molecular weight, heat absorbing and temperature regulating fibre can be spun by core- sheath spinning watanabe and thermo regulated fibre containing Micro PCMs.

4.4. ULTRA SMART TEXTILES

Very smart textiles are developing with or without the help of SOFT switch technology and related to spacesuits Musical Jackets Smart clothing (Remina Smart Suit] I -wear, Data wear, Wearable computers, Intelligent Interior surfaces, Flexible Computing Interfaces, Advanced Learning Products, Clinical Pressure Monitoring.

4.4.1. SPACESSUITS

The earliest developed Apollo spacesuits contained an inner layer of nylon fabric with network of thin walled plastic tubing which circulated cooling water around the astronaut to prevent over headings. This inner layer was comfort layer of light weight nylon with fabric ventilation ducts, than a three layer system formed the pressure garment. Net followed five layers of aluminized Mylar for heat protection mixed with four spacing layers of Dacron. These were covered with a non - flammable and abrasion - protective layer of Teflon - coated beta cloth. The outer layer was Teflon communication cloth. The backpack unit contained a life support system providing oxygen, waters and radio communications.