By: Prof. (Dr.) M. D. Teli

Among the diverse field of application of TechnicalTextiles, which is poised for tremendous growth in fast developing economieslike that of India and China, non implantable healthcare and hygiene productsare gaining significant importance because of specificity of their end uses.Protective textiles offer protection from hazardous chemicals, heat, extremecold, radiation and have special application potential in today'stechnologically advanced world. In addition to this, advent of nanotechnologyhas opened innumerable avenues giving rise to high performance textiles andapparels. This paper discusses overall status of this field and its scope forgrowth in near future.

The demography of India has been totally shifted towardsyoung population and the purchasing potential of this young population has beenincreasing. For this reason most of the developing countries are looking at India as a global market. India and China constitute over 40% population of the globe andapplication of technical textiles in this region will increase with a very highrate. The developed countries are much ahead of India with respect tomanufacture and consumption of Technical Textile. They are now finding a greatpotential to exploit the Asian market and hence, as per the industrialanalysis, the field of technical textiles is considered to be quite promisingfor the growth. Hence, those involved in textile business dealing with apparelsand also thinking of diversification or adding new line to their businessshould look at this segment of Technical Textile with a great promise.

The experience and the background of production as well assupply of conventional textiles as a whole will enable them to triumph in thesegment of Technical Textile. It does not however mean that the new comers inthis business cannot succeed.

As far as developed countries such as US & Japan are concerned, more than 35% of the textile industrial production is in terms ofTechnical Textile. For China it is over 19% and in India it is just 5% and thusthere is a very high growth prospect in Asia creating entirely a new market.Considering the fast growing (8%) economy of India and the significant size ofover 1 billion population, the presence of raw material, and well trainedmanpower, the technical textile field is surely going to develop at asignificant rate and so also its various segments such as Medical and HealthCare Textiles, Functional Textiles, Protective Textiles, etc.

Medical Textiles

The application of textile in the medical field requires anumber of properties for the fibre, depending upon where exactly this materialis used. The important aspects include non toxic nature of the material,ability to sterilize and to conform to the requirements of the mechanicalproperties as well as the bio-compatibility etc. All these properties areimportant since the material is expected to be free from contamination withbacteria and it is not supposed to be causing temperature rise of the personor chronic tissue inflammation or allergic reactions. Hence, it should benon-toxic. The bio compatibility is also equally important property.

Depending upon the end use application, the properselection of the fibre could be made.

In case of Protective health care textiles and apparels,the main purpose is to protect the health care professionals from gettingcontaminated by blood and other infectious material while dealing with thepatients. Many a times the surgeons, nurses as well as the attendants in theoperation theatre or emergency rooms are expected to wear the health caretextiles and apparels so that, they will get required protection. The productsunder this include operating and emergency room textiles, breathable membranes,caps for surgeon and nurses, masks, footwear's, coats etc. The need forprotecting the medical personnel is ever growing and thus increasinglyeffective health care garments and various barrier products are required to bemanufactured.

The biological protective garments are defined byoccupational safety and health administrative (OSHA) as follows: "Personnelprotective equipment will be considered appropriate only if it does not permitblood or other potentially infectious materials to pass through to or reach theemployees work clothes, street clothes, undergarments, skin, eyes, mouth orother mucous membranes under the normal conditions 01 use and for theduration of time which the protective equipment will be used.'

The surgical drapes are used in the operation theatre tocover patients or cover clothes. Many times, a nonwoven type is used having thebacking material on one or both the sides of the film. While the film ispermeable to bacteria, non woven backing is highly absorbent to both bodyperspiration and secretions from the wound. Surgical masks are made of 3layers. Middle layer of extra glass fibre or synthetic micro fibre is coveredon both sides by acrylic. The performance requirement for surgical face maskis high bacteria filtration capacity, high air permeability, light weight andnon allergic nature. The surgical caps are made of non woven cellulosic fibresusing spunlaid process or parallel process and now-a-days hydroentaglement isgaining popularity in producing disposable products and garments to be used inoperation room. The properties for the surgical drapes include stiffness barrierperformance for gowns as stiffness may affect the perspiration and movement.There should not be any linting which otherwise may carry particles to the wounds.

Flame resistance is needed during laser applications and oxygen administration. There are specific norms by CPSC and also National Fibre Production Association with respect to flame retardancy required for this product. The other Medical Textiles or Hygiene Textiles include bedding, shoe covers, mattress cover and wipes. Cotton leno woven blankets replace woollen blankets to reduce the risk of cross infection due to the water washability of the former. In isolation wards and Intensive Care Unit (ICU), composite fibres are used for protective clothing, incontinal textiles, diapers or bedding.

The disposable diapers have 3 layers: Inner covering layer, an absorbent layer and an outer layer. The inner covered hydrophilic finish treated polyester web or spun-laid poly propylene non woven bonded fabric as well as tissue papers are used in clothes and wipes having antiseptic finish. These clothes and wipes are used to clean the wounds. Surgical hosiery or knitted material have a lot of compressibility and are used to support the knees and also in the treatment of disorder and during physical injury.

Protective Textiles

In case of protective textiles, the industrial need is to offer the protection either from extreme heat and fire on one hand or from extreme cold on the other. Also protection from harmful chemicals, gases, bacterial environment, radiation etc. and ballistic protection which is also the form of mechanical protection is required. Low visibility textiles are used in military and defense purposes. These kind of textiles not only become the present need for accident free operations, but also it is by the legislations which are presently existing in the developed countries and which will soon be the part of human rights protection in our country. It has now become a law that the employer has to conduct the hazard assessment at the work place and provide the employee the proper safe surrounding and see that they wear safely designed and constructed protective clothing.

Of course, these products also had to adhere to certain international quality standards. As to the protection from high temperature, in the standard clothing asbestos and mineral fibres were used in the past. However, because of its carcinogenic nature, it has been withdrawn. By definition a material which can be used at a temperature more than 200C without decomposition and losing its physical property, is considered to be high temperature textile. It is important that due to the continuous exposure to heat, the strength of the fabric should not be decreased to a level lower than what is required as optimum. By using higher GSM of the fabric, its weight strength loss can be delayed.

The flame retardant clothes are designed to prevent ignition and even if they are ignited it is with a great difficulty. They have ability to get extinguished thus preventing the spread of flame. Flame resistant fabrics are obtained by using inherently flame retardant textile materials or treating the fibres or the fabrics with special flame retardant chemicals.

The requirement of flame retardant clothing includes ability to offer the protection from the flame, without compromising the comfort property and durability of such flame retardancy. Light weight garments with a flame retardant property is the present need and for a fire fighter, the moisture transferability along with flame retardant property becomes special requirement. As far as textile garment offering protection from flame is concerned, sewing thread should also be made of flame retardant material. The protective clothing should also have thermal comfort properties and thus under the higher outside temperature and humidity the vapours of sweat have to smoothly escape.

Flame retardant textiles find applications in fire fighters dresses, manufacture of furniture, airline suits, children sleepwear, etc. The fire fighters protective clothing system includes coat, pant, underwear, helmet, boots, gloves and breathing devices. While core property of resistance to flame has to be expected by such clothing, resistance to cut and punctures and mobility, water proofness, durability are other essential characteristics. In general fire fighting clothes of 3 layered material are made, the outer layer, the moisture barrier and the thermal barrier. The outer layer must be heat and flame resistance.

The two most common materials used for outer layer are Kevlar and PBI 60:40 and Nomex. The main purpose of moisture barrier is to keep the fire fighter dry and the material is expected to prevent water penetration. Woven and spun bonded substrates coated or laminated with neoprene or PTFE are commonly used as moisture barrier. Although the first two layers are flame resistant, the 3rd inner layer of thermal barrier offers proper protection against heat. Different fibres can be used after planning to form a composite. It has to be light and airy. While it is a multi layer garment, it has to also offer least resistance to movement of the body parts.

Chemical Protective Clothing (CPC)

In this case the body parts are isolated from hazardous chemicals coming in direct contact with them e.g. protection of the farmers from insecticides or truck drivers from chemicals toxic during loading or unloading and fire fighters from chemical substances. These CPC may be of encapsulating i.e. covering the whole body including the respiratory protection or non-encapsulation which is assembled from supported components and the respiratory apparatus may be worn outside the suit.

A number of products are manufactured and supplied by various manufacturers to offer protection from hazardous particulates as well as liquid and gaseous substances. The chemical protective clothing includes gloves, boots, face mask, aprons and also highly sophisticated system enable encapsulated suit.

Clean Room Textiles (CRT)

In case of CRT where the environment is protected from the wearer for clothing carrier a good amount of dust, ions, hair, tobacco smoke and it is said that the human body sheds 1 billion skin cells every day. The clean room textiles should be lint free, antistatic and should retard human contamination of textiles. Institute of environmental services recommends different types of garments for clean room. Woven, non woven and laminate fabrics are used for clean room.

The main properties of the fabrics require optimum filtration efficiency, moisture vapour transmission rate, static decay property and Flame retardance. The typical air permeability range is 1 to 45 cfm and typical filtration efficiency varies from 50-60% for particles measuring 0.3 to 0.5 microns. Conductive yarns such as carbon, nickel or aluminum can be woven in the clean room fabrics. The chemical protection ability and the flame retardency are added requirements during fabrication of clean room garment.

Protection from Radiation

People working in radioactive environment require such kind of outfits so that the transfer of radioactive materials to the human skin is prevented. Radiation protection is necessary for employees of nuclear plant, x-ray professionals and the workers working in cancer treatment centres. Nuclear protection fabrics are made of cotton, polyester cotton, nylon polyester. One of the techniques for use of protection from gamma, beta emissions from an artificial material is by shielding the same using lead (Pb) metal barrier between the radioactive dirt. Protective clothing from radiation include head cover, gloves, shoe covers, etc.

Protection from Extreme Cold

These insulating materials offer protection while playing the wonderful games under the extreme cold conditions. The material with fine denier yarn offers better insulation as compared to that of the coarser denier.

High Visibility Materials

HVMs have become very essential for the protection of pedestrians. Accidents in us 110ne in the night due to the vehicles, result in the death of more than 4,000 pedestrians and injury of more than 30,000 annually. In the dark, HVM clothes increase the detectability and application of such high visibility material (HVM) has resulted in 40% decline was observed in such road accidents. There are 3 main type of HVM:

1)       Reflection materials which shine when struck by light,

2)       Photo luminescent material which give yellow light in dark

3)       Fluorescent material which is visible during the day.

Textile substrates of these kinds are used in personnel safety products. Fabrics covered with reflective micro prison sheeting offer high visibility for personnel safety. They are used by pedestrians, cyclists, joggers, police etc. Personnel's working in airlines, law enforcement and medical field also make use of reflective materials. Photoluminiscent materials absorb the daylight or artificial light and emit green- yellow light in the darkness. Zincsulphide crystals which are non radioactive and non toxic pigments provide the visibility in the dark.

Nanotechnology Applications

The application of nano technology in the field of textiles and apparels is gaining increasing importance. Nanotechnology is defined as the utilization of structures with at least 1 dimension of nano size for the construction of material with improved properties owing to such a small size. Commonly, the products in the range of 1100 nano meters are considered to be nano particles. It has been proved beyond doubts that permanent effect with improved performance properties even after repeated laundering are possible in case of textile goods manufacturer using nano technology.

Nano particles have high surface area to volume ratio and thus present increased affinity for fabric which leads to improved durability. Some of the finishes based on nano particles are found to maintain the breathability and soft hand. A US based Berlinton industry first reported the nano technology application under the trade name Nano-text. The nano materials can be applied to textile by coating using various other ingredients and by varying the technology of coating. Out of the many possible applications in textile, some of the most successful one are water repellence, soil resistance, UV protection, anti bacterial and anti static finishes and as well as wrinkle resistance.

Wrinkle Resistance: In order to impart wrinkle resistance, normal procedure is to use resin precondensates. However, to overcome the limitations of resin, nano Titanium dioxide and nano silica are employed using polycarboxylic acid as a catalyst under UV radiation to catalyze the cross linking reaction between cellulose molecules and the acid. On the other hand, the application of nano-silica with maleic anhydride showed successful improvement in the wrinkle resistance of silk.

Anti Bacterial property: Nano silver Titanium dioxide and nano Zinc oxide are found to impart sterilizing effect with anti bacterial property. Nano silver particles with large surface area improve their contact with bacteria or fungi, inhibit cell growth by affecting the cellular metabolism and thus act as effective bactericide or fungicide. Nano silver particle is used in socks and other health care products such as dressings for burns and skin donor, etc. Nano Zinc oxide can also be used as a good photocatalytic agent having anti bacterial property. Self cleaning suits make use of a film polymer of polyglycidylacrylate mixed with nano silver which has inherent property of imparting anti microbial or odor free effects.

Antistatic Properties: Synthetic fibres are notorious for development of static large and thus durable anti static finishes are required to be given to these fibres to enable processing of them free of problems. Nano size titanium dioxide, zinc oxide, viscous and nano antimony dioxide, tin dioxide have been found to provide anti static effect, as they are electrically conducting materials causing the effective decay of static charge.

UV Protection : Titanium dioxide, zinc oxide, silicon dioxide and aluminum dioxide are some of the semi conductors which are used as inorganic UV blockers and these materials in nano size are highly efficient in absorbing and scattering UV radiation. Due to the minute size of the particles, the lights scattering predominate at approximately 1/10 of the wave length of the scattered light and hence for UV radiation to be scattered in the 200-400 nano metre, optimum particle size required is about 20-40 nano metre. The UV blocking treatment for cotton fabric consists of forming a thin layer of titanium dioxide on the surface of the treated cotton fabric which in turn found to give a very high UPF.

Nano Finished Garments: In general the nano finished garments offer protection due to a coating which is water and beverage repellent. The naked eye cannot detect the protective layer due to the near about 100 nano meter size of finish on the clothing which is water and dirt resistant. A lot of saving on laundry time and cost can be obtained with good feel and breathability as well as resistance to wrinkles. The finish is non toxic in nature and bright and fresh looking. These are value added effects with environment friendly technology.

Functional textiles have opened a new vista of applications in diverse field of human life. Many of these applications are highly crucial and thus these materials with high end performance properties are going to play paramount role in the life of modern man. Surely in the fast developing economy like ours, the growth of such Textile Materials will take place at galloping rate. Not only will it act as the driving force for R&D activities, tapping hitherto untapped field of Functional Textiles and Apparels, it will also be a great booster to our economy and to the same extent it will slowly reduce India's dependence of imported Technologies in this field.

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