Technical Textile

Friday, 31 August 2012

Development of Insect-Repellent Wipe for Indian Travel and Tourism Industry

ABSTRACT

Currently, Insect-repellents are most widely used in India for protection against insects and other parasites. Owing to the various diseases caused by insects (e.g. Malaria, Dengue, Chikungunya, Typhoid, etc.), the demand for insect-repellents in cream, liquid and spray form is increasing every year. However, none of the currently available products (i.e. insect-repellent lotion, cream, spray and coil) are friendly for frequent travelers as it doesn’t provide any guidance regarding quantity to be applied for maximum insect-repellency. Additionally, the packing is not optimized and suitable for travel and tourism industry.

This project aims to develop a cost-effective disposable insect-repellent wipe for the Indian travel and tourism market. The wipe has also been optimized as per different age groups and body parts. The spunlace nonwoven materials are being used for the initial feasibility study. The proposed formulations are being optimized so that each wipe provides maximum insect-repellency and sufficient time to the user before it dries up. An innovative way of incorporating insect-repellents to the nonwoven substrate has been studied in order to provide a longer ‘insect-free time’ to the user. The feasibility study also incorporates application of dry insect-repellent formulations which can be triggered by impregnating in water while applying on skin. This will reduce the cost of transportation and increase the shelf-life of our newly developed wipes. Additionally, a herbal insect-repellent, neem, has also been tested which can be used by persons having sensitive skin

Keywords: Wipe, Aroma, Insect repellent, Insect Free time, Super Absorbent Polymer, Spunbonded nonwoven, Spunlace nonwoven, Chicken blood and Mosquito net.

1. INTRODUCTION

Insect-repellent wipe is a fibrous structure impregnated with Insect-repellent formulation. These wipes helps in driving the insects away thus protecting you from bite. The wipe has this kind of aroma which keeps insects away but that can not affect your nose. There are insect repellents available in the market and mostly it comes in spray, however spraying it on your room could give you a very itchy nose. It is known that the human blood is very delicious for insects therefore these repellents work by covering the blood fragrant with its own fragrance. The aroma from those repellents are scattered therefore the insects will not think that you are in the place or in the room, therefore it is really effective.

Fig. 1 Insect-Repellent Wipe

However there are some repellents that irritate not only the insects but also the person using it. For those users that have very sensitive skin they feel like their skin is burning when they applied the repellent in lotion form. Therefore, it is best to choose those repellents that are made of natural ingredients so that the sensitive skin won’t get irritated. There are also users that have very sensitive nose so they have to choose those repellents that have an aroma that is not that strong yet effective. This wipe provide the maximum insect repellency with a optimized quantity of Insect repellent formulation with easy to use, Additionally a Eco Friendly wipe is being also developed using neem and tulsi which provide the insect-repellency and which can be used by person having skin problems. The probability of insect biting is more near the wounded parts of the human body and generally the commonly used insect repellent chemicals are not suitable to apply over the wounded parts but this eco friendly wipes which uses neem can be applied even on the wounded parts of the body these products not only provide insect-repellency but will also helps in healing the wounds. So, these products can be really use full. Apart from this the wipes are very easy to apply and the formulation can be applied evenly/uniformly over the exposed body parts.

The Table: 1 enlists the advantages and disadvantages of currently available Insect-repellent products.

Table: 1 Comparison of Currently available Insect-repellent Products

Products available	Advantages	Disadvantages
Cream and Lotion (Odomoss, Goodnight)	Easy to apply	Quantity as per age group, weather conditions, body parts not known. ‘Insect-free’ time not established. May cause skin irritation.
Spray (Hit)	Effective in closed environment	Not suitable during travelling.
Coils(Mortein, Maxo) and Liquids (All out, Mortein)	Effective in closed environment	Not suitable during travelling.

So, from the above table it is clear that the currently available products are not suitable during travelling and it leads us to develop a completely new and innovative product “Insect-Repellent Wipe” for Indian Travel and Tourism Industry.

2. TYPES OF INSECT-REPELLNT WIPE

The Insect-repellent wipes can be made into two types:

2.1 Wet Wipe These types of wipes can be defined as a fibrous structure wetted with aqueous solution of insect repellent formulation which helps in repelling the insects.

2.2 Dry Wipe These type of wipes can be defined as a fibrous structure with dry insect-repellent formulation which can be triggered by impregnation with water or other solvent prior to application on skin and thus when applied providing the insect repellency.

The Table: 2 gives the idea of suitability between Wet and Dry wipe for use.

Table: 2 Comparisons between Wet and Dry Wipe

Parameters	Wet Wipe	Dry Wipe
Application on skin	Ready to use	Require Water or solvent
Transportation cost	More	Less
Shelf life	Less	More

So, from the above table it can be seen that Dry wipe is superior to Wet wipe in terms of Shelf Life and Transportation cost (as it weigh less) but it will require Water or solvent in order to apply it over the Skin.

3. MATERIALS AND METHODS:

3.1 Material The Different Materials used for the Development of Insect-repellent wipe are:

Ø A Fibrous Structure of Spunlace and Spunbond nonwoven for wipe.

o Spunbonded Nonwoven 60 GSM (100% polypropylene)

o Spunbonded Nonwoven 65 GSM (polyester-67% and Viscose-33%)

o Spunlace Nonwoven 45 GSM (polyester-50% and Viscose-50%)

o Spunlace Nonwoven 45 GSM (polyester-70% and Viscose-30%)

Ø DEET (N, N-diethyl benzamide-12%), Neem oil and powder extract as insect-repellents.

Ø Super-absorbent (SAP) polymers/fibres.

Ø Chicken blood sample to evaluate repellency.

3.2 Preparation Method

The Five different types of Insect-repellent wipe has been developed namely

Ø Wipe A

Ø Wipe B

Ø Wipe C

Ø Wipe D and

Ø Wipe E

3.2.1 Wipe A

The Wipe A is Prepared using a Spunbonded nonwoven 60 GSM (100% polypropylene). The nonwoven fabric is impregnated in Insect-repellent formulation DEET (N, N-diethyl benzamide-12%)/ Neem oil for about 8 hours at 27 ºC.

3.2.2 Wipe B The Wipe B is Prepared using a Spunbonded nonwoven 65 GSM (polyester-67% and Viscose-33%). The nonwoven fabric is impregnated in Insect-repellent formulation DEET (N, N-diethyl benzamide-12%)/ Neem oil for about 8 hours at 27 ºC.

3.2.3 Wipe C

The Wipe C is Double Layered wipe in which the Top layer is like Insect-Repellent wipe A which is impregnated in Insect-repellent formulation DEET (N,N-diethyl benzamide-12%)/ Neem oil for about 8 hours at 27 ºC. and SAP(Super absorbent Polymer is sprinkled between the two layers as shown in Fig. 2 to increase the moisture holding capacity thus Increasing the Drying time of wipe and giving the more time to user for applying the wipe over his/her exposed body parts. The SAP if inhaled can cause some serious problems in breathing as it swells when comes in contact with moisture. So, later on the Super Absorbent Polymer is replaced by Super Absorbent Fiber. Fig. 2 Sprinkling of SAP over Bottom layer

The Wipe C (Fig. 3) has Insect-repellent formulation only on one side and other side of the wipe is dry so it becomes easy for user to apply without getting unnecessary amount of Insect-repellent formulation over his/her hands. The two layers of nonwoven fabric can be fusion bonded which is more easy by using fibers having low melting temperature e.g. polypropylene and polyolefin.

Fig. 3 SAP is sandwiched between two layers

3.2.4 Wipe D This wipe falls into category of Dry Wipe, the wipes discussed above are wet wipes. This wipe is also Double Layered. In preparation of Wipe D the dry powder of Insect-repellent is sprinkled between two layers of nonwoven fabric as shown in Fig. 4 which can be triggered by impregnating in water prior to applying on skin. Initial trials have shown that this concept can reduce the cost of transportation and increase the shelf-life of our newly developed wipes. The two layers of nonwoven fabric can be fusion bonded which is more easy by using fibers having low melting temperature e.g. polypropylene and polyolefin.

Fig. 4 Dry Insect Repellent between two nonwoven layers

3.2.5 Wipe E

This wipe is multilayered wipe having three layers of nonwoven fabric namely bottom, centre and top layer. (65 gsm/45 gsm/45 gsm) as shown in Fig. 5.

The SAP is sprinkled between bottom and centre layer whereas dry insect-repellent formulation is applied between centre and top layer. Thus the Sprinkled SAP helps in providing more Drying time to for Dry Wipe thus giving more time to user for applying it over the exposed body parts. The Wipe E has Insect-repellent formulation only on one side and other side of the wipe is dry so it becomes easy for user to apply without getting unnecessary amount of Insect-repellent formulation over his/her hands.

Fig. 5 Three layered wipe with Dry Insect-repellent formulation and SAP

The two layers of nonwoven fabric can be fusion bonded which is more easy by using fibers having low melting temperature e.g. polypropylene and polyolefin.

3.6 Testing Method

The Wipes are being tested for Insect repellency with the help of Chicken Blood which attracts the insects. The experiments were conducted in a closed mosquito net by trapping insects inside. The nonwoven fabric is treated with Chicken blood which will attracts the insects and over that the wipes are kept in a closed mosquito net with trapped insects for checking the insect repellency. After few hours the same wipe is again tested for insect repellency so that its protection time can be determined. The whole assembly for testing the insect repellency is shown in the Fig. 6. Fig. 6 Testing assembly for checking the Insect Repellency

4. RESULT AND DISCUSSION

4.1 Drying time

When a wipe is opened up to use after some time the wipe get dried as all the moisture get evaporated the time taken by the wipes to get dry depends upon the weather and wind condition. So user get a limited time for applying the wipe over his/her exposed body parts. So a study has been done on the drying time provided by different wipes. The Drying time of different wipes are shown in Fig: 7.

Fig: 7 Comparison of Drying Time for Different Wipes

This shows that wipes with SAP take longer to dry providing sufficient time for the application of repellents.

4.2 Insect Repellency The wipes has been tested for the insect repellency (It’s ability to repel insects) for this first a testing assembly as shown in Fig. 6 is prepared and then a insect is trapped inside a closed mosquito net with a chicken blood sample inside which will attract the insect to come over it but our newly developed insect repellent wipe is kept over it which will drive the insects away as shown in Fig. 8.

As shown in Fig. 8 there is no insects coming over the Blood Sample as it is covered by the Insect Repellent wipe but after few hours the effect of wipe is getting demolished as tested under the same condition the Fig. 9 is result after 6 hours at which insects are coming over the Blood Sample.

Fig. 8 Insect repellent wipe over Blood Sample(DEET)

Fig. 9 Insect Repellent Wipe Over Blood Sample after 6 hours (DEET)

Fig. 10 Insects coming onto the Blood Sample

To check wheather the Blood sample will attract the insects or not the same experiment is done withouut the Insect repellent wipe. The Fig. 10 shows the complete attraction of insects over the Blood sample as the Insect repellent wipe is removed from the top of the Blood sample so insect starts coing over it.

4.3 Optimization study for various age groups

A study is currently being carried out to optimize the amount of formulation required for different age groups to get the maximum repellency. The Fig: 11 shows the amount of insect-repellents required in grams:

Fig. 11 Optimization of Insect Repellent according to Body Parts and Age Group

5. CONCLUSIONS

• Insect-repellent wipes can be developed for Indian travel and tourism industry.

• Multilayered dry wipes are superior option than that of single layer wet wipes for insect-repellency.

• SAP can be used to increase the drying time.

• Insect-repellent formulations can be optimized as per different age groups.

• Natural products such as Neem extracts can be used to develop insect-repellent wipes.

6. REFERENCES

1) Information on www.allbusiness.com/sector-44-45-retail.../1187809-1.html

2) Information on http://timesofindia.indiatimes.com/city/delhi/Dengue-risk-at-Games-venues-angers-HC/articleshow/6477411.cms#ixzz12GgXUdm6

3) Information on http://www.myinsectrepellent.com/ar/3m-insect-repellent.php

4) Information on http://www.myinsectrepellent.com/ar/insect-repellent-clothing.php

5) Information on http://en.wikipedia.org/wiki/Insect_repellent

6) Information on http://www.malariasite.com/malaria/MalariaInIndia.htm

7) Information on http://en.wikipedia.org/wiki/Superabsorbent_polymer

8) Wet Wipes, Ho-ward J. Yoh, W. Berlin, N.J, United States Patent 4904524 Feb. 27 1990.

9) Insect Repellents, Richard Arthur Birch, Hyth (G.B), Henk Helweg, Huizen (N.L) United States Patent US 7455852B2, November 25 2008.

10) Process and System for Impregnated Garment with Insect Repellent, Bartley F. Mcnally, North Providence R.I. United States Patent 5884418, March 23, 1999.

11) System for Impregnating Garment with Insect Repellent, Bartley F. Mcnally, North Providence R.I. United States Patent 5930909, Aug 3, 1999.

Fire Retardant Clothing for Personnel Protection

Abstract:

With the developments in modern technologies there is a vast increase in the kinds of hazard to which workers are exposed. Therefore the need of Protective clothing is also increasing to ensure the safety of peoples and the work place. Protective clothing refers to garments and other fabrics related items designed to protect the wearer from harsh environmental effects that may result in injury to death. Protective textiles have become an integral part of our milieu in one or the other form. These textiles are designed to protect the wearer from harsh environmental effects that may cause injury or may turn out to be fatal. The biggest need in the personnel and property protection is the protection from fire hazards. Protection from heat, flame, molten-metal splashes, severe cold and frost, radiation sources, etc is a prime requirement for both civil and defense applications. For many peoples in this world fire is an unavoidable part of their daily work. The fire fighters and the peoples involved in the industries such as steel, glass, cutting stations, edge working, glass toughening, automotive, light assembly, coal mines, etc. needs to have protection against fire. Fire causes the loss to both personnel and property. Every year many peoples around the globe die because of fire and it also causes the loss to the property. So it becomes very necessary to use the fire retardant clothing in required places, area and by personnel. In many countries there are set norms to use the fire retardant clothing in certain places. This paper discusses the need of fire retardant clothing, mechanism and its importance in personnel and property protection (PPP). The various technique and fibers used in fire retardant clothing along with its area of application has also been discussed.

Keywords: fire, hazards, pyrolysis, combustion, splashes, ignition, inherently.

1. Introduction

Textiles are found everywhere in modern society. The textiles are used in numerous applications other than simple clothing. One of these applications includes protective textile, which is used for the protection from various hazards. Protective textile is an ensemble of textile products and related material used in the manufacture of various protective clothing for personnel working in hazardous environment. Protective textile refers to garments and other fabrics related items designed to protect the wearer from harsh environmental effects that may result in injury to death. Protective textiles have become an integral part of our milieu in one or the other form. These textiles are designed to protect the wearer from harsh environmental effects that may cause injury or may turn out to be fatal. The protective clothing includes garments and related paraphernalia used for protection against extreme heat and fire, extreme cold, toxic chemicals and gases, mechanical hazards, electrical hazards, radiation, etc². Some of the different protective clothing used against different hazards are:

1) Ballistic Protective Textile

2) Chemical and Biological Protective Textile

3) Fire Retardant Textile

4) Mechanical Protective Textile

5) Radiation Protective Textile

6) Foul Weather Protective Textile/High Visibility Clothing

7) High Altitude Clothing

Fig: 1 Fire Retardant Clothing

The safety of human beings has become an issue of concern with rapid industrialization. Therefore, a growing segment of the industrial textiles industry has been involved in a number of new developments in fibers, fabrics and protective clothing². Indian Defense Forces with a total strength of around 1.5 million individuals comprising the army, navy and air force, is one of the largest consumers of protective textiles⁸. Approximately 25-30 % of the troops is involved in high risk, counters insurgency & special operations in super high attitude areas and requires protective clothing. In addition, around 1.2 million individuals are present in paramilitary forces and other security forces. In the last decade, extensive work has been carried out in a number of laboratories to develop protective clothing for both industrial workers, and the army. Protective clothing made from woven, knitted, nonwoven fabrics have been designed to suit specific requirements, and performance-evaluation techniques to simulate the work wear conditions have been developed.

Health and safety at work requires protective textiles for certain jobs and the threat from fire at work place is currently a topical issue. The range of hazards and the means of combating them continue to grow and become ever more complex. A consequence of this is the development and exploitation of new textile fibers, structures and clothing systems whose purpose is to provide improved protection, whilst maintaining comfort, efficiency and well being¹. The production of environment friendly, non-toxic, flame retardant systems that compliment the comfort properties of textiles have been the major challenges to coatings and fabrication technology⁴.

Flame resistant clothing protects the wearer from flames or flares, flying slag, metal droplets, and red-hot sparks. The primary purpose of flame resistant clothing is to delay the increase in skin temperature caused by heat exposure in order to give the wearer time to escape the source of the flames and avoid or minimize the risk of burns. Using different fibers, fabrics or weaves, it is possible to provide protection against noise, insulation against the cold, heat and fire or a combination of these qualities. In many situations fire retardant work wear should provide insulation against heat as workers in many industries are exposed to direct flame as well as heat^{9, 18}.

2. Need of Fire protection:

Probably it is the biggest need in the world today. Protection from heat, flame or flares, molten metal splashes, metal droplets, and red-hot sparks etc., is a prime requirement for both civil and defense applications. For many peoples in this world fire is an unavoidable part of their daily work. The fire fighters and the peoples involved in the industries such as oil, iron, steel, metal, chemical, welding, electrical steel, glass, cutting stations, edge working, automotive, light assembly, coal mines, etc. are routinely exposed to potentially harmful situations or hazards like fire, electrical sparks and fluctuating temperature etc.

Several workers die every year due to fire related injuries. As per National Crime Records Bureau of India there were 23,360 deaths (64 deaths per day) due to fire in India only during 2009, and many more suffered the fire related injuries. The deaths due to fire have a share of 6.5% of total deaths during 2009 in India by natural and unnatural causes³. So this shows there is a very much need of the fire retardant clothing. Fig: 2 Fire Hazard

Thermal risks in fire situations against which the human skin has to be protected may be due to:

flame (convective heat), contact heat, radiant heat, sparks and drops of molten metal, hot gases and vapours. Human tissue is very sensitive to temperature. Total heat energy as low as 0.64cal/cm²results in a sensation of pain, and 1.2 cal/cm²causes second-degree burns on exposed tissues. At 45^OC, the sensation of pain is experienced, and at 72^OC the skin is completely burnt. The purpose of protective clothing is therefore to reduce the rate of heating-up of human skin in order to provide the time the wearer needs to react, to escape, and to avoid or minimize burns.

3. How Textiles Catches Fire

Combustion of textiles is a complex phenomenon that involves heating, decomposition leading to gasification, ignition, and flame propagation. Combustion in textiles is a cyclic phenomenon. It’s a self catalyzing process. The main requirements to burn textiles are heat, oxygen & fuel. When heat is given to a cloth, its fibers get heated. The effect of heat on a fiber can produce a physical as well as a chemical change. In thermoplastic fibers, the physical changes occurs at second order glass transition temperature(Tg) and subsequently melting occurs at a melting temperature Tm_,whereas chemical changes take place at pyrolysis temperature(Tp) and combustion temperature(Tc). At Tp fiber undergoes thermal degradation and at Tc subsequent oxidation and combustion may occur. When heat is given to fiber, at Tp it pyrolysis and if produced volatile liquids and gases are combustible, they act as a fuel for further combustion. If oxygen is present in sufficient quantity and after pyrolysis the temperature is equal to or greater than Tc, the flammable volatile liquids burn to give products such as carbon dioxide and water and thus putting the material on fire. In fact, when a textile is ignited, heat from an external source raises its temperature until the structure begins to degrade. The rate of this initial rise in temperature depends on the specific heat of the fiber, its thermal conductivity and also the latent heat of fusion, vaporization or other changes that occur during the combustion of the material¹. Fig: 3 Mechanism of combustion

3.1 Thermal and Fire Retardant Parameters for Fibers

When solid materials are heated it undergoes physical and chemical changes at specific temperatures depending on the chemical make-up of the solid. Thermoplastic polymers soften at the glass transition temperature (Tg), and subsequently melt at Tm. At some higher temperature (Tp), both thermoplastic and non-thermoplastic solids will chemically decompose (pyrolyse) into lower molecular weight fragments. Chemical changes begin at Tp and continue through the temperature at which combustion occurs (Tc). These four temperatures are very important when considering the flame resistance of fibers. Another important factor in combustion is the Limiting Oxygen Index (LOI). This is the amount of oxygen in the fuel mix needed to support combustion. The higher the number, the more difficult it is for combustion to occur. Natural fibers are not thermoplastic, therefore when they are subjected to a heat source, pyrolysis and combustion temperatures are encountered before softening or melting temperatures are reached and eventually ignite. On the other hand, low melting thermoplastic fibers will melt and drip away from the flame before pyrolysis and combustion temperatures are reached. However if the melt does not shrink away from the flame front, pyrolysis and combustion temperatures are eventually reached and ignition will occur.

In textile material ignition from a flaming source should be low or if the material ignites, the fire spread should also be low with minimum heat output. This makes these materials suitable to be used as protective clothing. In general, thermoplastic fibers or fabrics such as nylon, polyester and polypropylene fibers fulfill these requirements because they shrink away from flame and if they burn they do so with a small slowly spreading flame and ablate. However, for protective clothing there are additional requirements such as protection against heat (as workers are exposed to it during their course of work) by providing insulation as well as high dimensional stability of the fabrics. So that upon exposure to the heat fluxes they will neither shrink nor melt, and if they then decompose, form char. The above mentioned requirements cannot be met by thermoplastic fibers as wearer exposes to direct heat and to burns caused by contact of the molten mass with the body. So the high performance fibers such as aramid fiber started being used against heat and fire. It may also be noted that the aramid fibers, in spite of their high oxygen index and high thermal stability, have not been found suitable for preventing skin burns in molten-metal splashes because of their high thermal conductivity. The mode of decomposition and the nature of the decomposition products (solid, liquid, and gaseous products) depend on the chemical nature of the fiber and also on the type of finishes or coatings applied to the fabrics. If such decomposition products are of a flammable nature, the presence of atmospheric oxygen gives rise to ignition with or without flames. When the heat evolved is higher than that required for thermal decomposition, it can spread the ignition to cause the total destruction of the material⁴. The thermal and flame-retardant parameters of some fibers are given in the Table: 1.

Table: 1 Thermal and flame-retardant properties of fibers^{1, 4}

Fiber	Tg (⁰C) (Glass Transition)	Tm (⁰C) (Melting)	Tp (⁰C) (Pyrolysis)	Tg (⁰C) (Combustion)	LOI
Wool	-	-	245	600	25.0
Cotton	-	-	350	350	18.4
Viscose	-	-	350	420	18.9
Triacetate	172	290	305	540	18.4
Nylon 6	50	215	431	450	20.0-21.5
Nylon 6.6	50	265	403	530	20-21
Polyester	80-90	255	420-477	480	20-21.5
Acrylic	100	>220	290	>250	18.2
Polypropylene	-20	165	469	550	18.6
Modacrylic	<80	>240	273	690	29-30
PVC	<80	>180	>180	450	37-39
PVDC	-17	180-210	>220	532	60.0
PTFE	126	>327	400	560	95.0
Oxidized acrylic	>640	-	55	-	-
Nomex	275	375	310	500	28.5-30
Kevlar	340	560	590	>550	29
PBI	>400	-	>500	>500	40-42

High performance fibers aid enormously in allowing products to meet these challenges. High performance fibers and high temperature resistance fibers offer numerous advantages over traditional materials. Higher strength, light weight, higher operating temperatures and flame retardant ability are some of the most prominent features of these fibers. These outstanding properties create opportunities to manufacture products that historically could not be made due to technical constraints.

3.2 Fire Retardant Clothing needs to meet these requirements:

· Flame-resistance (it must not continue to burn and be a hazard)

· Integrity (the garments should remain intact, that is, not shrink, melt, or form brittle chars, which may break open and expose the wearer)

· Insulation (garments must retard heat transfer in order to provide time for the wearer to take evasive action, during combustion, they must not deposit tar or other conductive liquids)

· The Fire retardant clothing must have high dimensional stability and breathability.

· Fume toxicity should not be there in fire.

· Liquid-repellency to block dangerous chemicals (this is sometimes necessary to avoid penetration of oils, solvents, water, and other liquids)^{8, 15}.

4. Fibers used in Flame Retardant Protective Clothing:

Such fabrics can be made by selecting special fibers which are:

· Inherently flame retardant, like aramid fibers(Kevlar, Nomex and Conex), modacrylic fibers, polybenzimidazole (PBI) fibers, semicarbon fibers and phenolic fibers.

· Chemically treated fiber/fabric by using flame retardant finishes, where fabric is treated with chemicals to impart flame retardancy.

4.1 Inherently flame retardant fibers

4.1.1 Aramid: Aramid fiber is a heat-resistant and strong synthetic fiber; these fibers have unique properties that set them apart from other fibers. Aramid fiber tensile strength and modulus are significantly higher than those of earlier organic fibers, and fiber elongation is lower. Aramid fibers can be woven on fabric looms more easily than brittle fibers such as glass, carbon or ceramic. They also exhibit inherent resistance to organic solvents, fuels, lubricants and exposure to flame. In Para Aramid (Kevlar), the polymer chains are very stiff, brought about by bonding of rigid phenylene rings in the para position. In contrast, for Meta Aramid (Nomex), the phenylene and amide units are linked in the meta position, which results in an irregular chain conformation and a correspondingly lower tensile modulus. The LOI Value for Para Aramid (Kevlar) and Meta Aramid (Nomex) are 29 and 30 respectively.

It is used in aerospace and military applications for Fire-Retardant Clothing and Bullet-proof body armor fabric and as a substitute of Asbestos. It provides long-lasting protection. Whether it is found in protective suits, underwear, socks or gloves, the exceptional flame-resistance provided by aramid cannot be washed out or worn away. They begin to char at about 400 °C with little or no melting, have low flammability and ensure good fabric integrity at elevated temperatures⁵.

4.1.2 Semi Carbon or Panox: Panox is used when it comes to industry standard fire-retardant textile fibers. Panox is an oxidized, thermally stabilized polyacrylonitrile (PAN) fiber. Panox fiber does not burn, melt, soften or drip. Panox can be easily processed into yarns, woven fabrics, nonwovens and felts. This fiber has excellent flammability classification S-a (DIN EN 532/533), High thermal stability, High LOI (Limiting Oxygen Index) value. The LOI value for Panox is 29%.

4.1.3 Polyphenylene Sulphide: It has exceptional heat and flame resistance property. They do not support combustion under normal atmospheric conditions, and the LOI is 34–35%. Chemical resistance and the ability to retain physical properties under extremely adverse conditions make the fiber valuable for protective clothing with a low density of 1.34 g/cm3. Maximum Constant Temperature can be sustained is 200⁰ C.

4.1.4 PBI (Polybenzimidazole): PBI fiber is a high-performance fiber recognized for its exceptional thermal stability and chemical resistance. These two qualities, along with its excellent textile processing characteristics, have secured PBI fiber a unique position in the high-performance fiber markets. PBI gains much of its thermal stability from the fact that it is a wholly aromatic, ladder-like polybenzimidazole structure. PBI fiber does not undergo sustained burning in air. The lowest concentration of oxygen that will sustain burning is 41%. Fabric produced from PBI fiber exhibits no after-flame and minimal char length (10 mm or 0.4 inches) in vertical flammability test (FSTM 191–5903). This further confirms PBI’s exceptional flame resistance. The PBI retains integrity up to 450°C. The fiber first used in spacecraft applications. Even today it is popular in military and aerospace applications due to its thermal stability and ability to retain fiber integrity even in exposure to flame⁵.

4.1.5 PBO: PBO fibers exhibit very high flame resistance and have exceptionally high thermal stability (onset of thermal degradation in the 600–700 °C range). PBO fibers also have very good resistance to creep, chemicals and abrasion. However, the poor compressive strength of these fibers restricts their use in composites. PBO fabrics are light and flexible, providing improved comfort and mobility, and are ideal for heat and flame resistant work-wear such as for fire fighters. Motorcycle suits have particular areas, such as the knee and elbow regions, reinforced with PBO fabric, providing the required excellent heat, flame and abrasion resistance. The LOI value for PBO is 68%⁵.

4.1.6 Modacrylic: It is inherently flame resistance acrylonitrile fibers, can be used in chemical plants and tyre manufacturing plants since it is resistance to most acids, alkalis and bleaches. Modacrylic has properties that are similar to an acrylic. However, modacrylics are flame retardant and do not combust. The fibers are difficult to ignite and will self-extinguish. Modacrylic fibers have a moderate resistance to abrasion and a very low tenacity. They also have great dimensional stability and high elastic recovery, which gives them the ability to hold their shape. The lowest concentration of oxygen that will sustain burning is 29%. Modacrylics have the ability to combine flame retardancy with a relatively low density, meaning protective gear is not uncomfortably heavy (i.e. shirts and trousers worn by electrical linemen). The combination of flame retardancy and low density is also useful in furnishings, draperies.

4.1.7 Vinex: This is fire resistance comprised of 85% inherently flame resistant vinyl and 15% polynosic rayon. It retains its flame resistant properties throughout the service life of the garment. The fabrics produced from vinex are used as protective clothing at major aluminum companies worldwide. It also has good comfort properties. Vinexis specifically engineered to perform as a specialty protective clothing fabric for use in the aluminum industry because it exhibits a unique ability to shed molten metal. Since insulation from thermal heat sources is directly related to fabric weight, heavier weight styles of vinex will offer more protection from second-degree burns than lighter weights. Many aluminum companies have also performed in-house splash tests to determine the protection level required for their unique situation.

4.1.8 Polyacrylate fiber: Polyacrylate is a crosslinked copolymer of acrylic acid and acrylamide. It’s a nonflammable fiber has an LOI of 43%. When subjected to a flame, it neither burns nor melts. It emits virtually no smoke or toxic gases. It has very good fire resistance properties but due to its low strength and brittleness durability of Protective clothing may not be adequate. This fiber also offers protection from attack by chemicals, including strong acids and alkalis, it may be found useful in filtration of liquids and hot gases⁴.

4.1.9 Phenolic or novoloid fibres: Phenolic are highly fire retardanr fiber. The fabrics made from these fiber can withstand short term exposure to an open flame without damage or shrinkage. Their ignition temperature is above 2500⁰C and the Limiting Oxygen Index is 30-35%. Kynol, Philene and Basofil are the type of phenolic fiber.

4.1.10 Glass: Silica based fibers that provide insulation and also flame resist characteristics, are also popular for use as fire protective clothing. They are used for protective apparel and also the fire extinguisher covers. Glass fiber fails to provide comfort characteristics to the wearer. Hence it is coated with PU, silicones, or aluminized polyester film to improve the comfort properties along with flame resist and heat barrier properties⁴.

4.2 Chemically treated fiber/fabric.

Fabrics which have been treated with flame retardant chemicals unlike inherently flame resistant fabrics suffer from the drawback that their efficacy will diminish over time. As the Fabric is washed subsequently their flame retardancy also gets washes away and also with the use of clothing its flame retardant property is rubbed off. By contrast, the flame resistant properties of fabric composed of inherently flame resistant fibers are permanent and will remain effective until the garment itself has worn out.

There are various chemicals and agents available for different type of fiber for making them flame retardant. However the treated flame retardant fabric mainly uses the Pyrovatex and Pyroguard treatment as coating material on Cotton. Pyrovatex and Pyroguard are the more commonly use treatment on cotton.

The treated flame retardant fabric are mainly used where washing of textile is not so often e.g. curtains, sheers, upholstery, stage curtains, blankets, bedding, wall coverings, blinds and others home textile products.

5. Application

5.1 Firefighters’ Suits: The fabric has three layers, an outer shell, a vapour barrier and a thermal barrier. A batting or a needle punched construction in fabric uses as linings on inside or on both sides. The shell fabrics used were of aramid fiber, an aramid/novoloid fiber blend, and FR cotton. Proper protection against heat and flames is essential for fire fighters. When entering a dangerous environment, the fire fighter must be confident that he/she has the best protection available. Fig: 4 Fire fighter’s Suit

Clothing for Naval and Armed-forces Personnel: It is mostly made up of lightweight Nomex fibers. It is used by men working at board ship. Garment used here must provide protection against cold also.

5.2 Oil Refinery: Fire is a hazard in Oil Drilling both offshore and onshore, refineries, pipeline maintenance and where ever there is a risk of flame or explosion. The work has to be done, even when the risk of the fire cannot be completely averted in mind, the hazardous work environments of offshore drilling units where the workers needs protection not only against flame but also against water and oil.

Fig: 5 Workers in Oil Refinery

5.3 Iron and steel industry: This is the most hazardous work place where the workers are exposed not only to high temperatures but also to the risk of open flame and large splashes of molten metal. To provide adequate protection to the workers in this industry the Fire Retardant clothing should be provided to the worker.

Fig: 6 Worker exposed to heat at steel industry

Some of the big steel producers such as Tata Steel, Steel Authority of India Ltd, Ispat Industries and Essar Steel are making significantly higher investments in this area.

5.4 Chemical industry: The handling of chemicals in a production facility can represent a potential fire hazard therefore, workers need to be protected.

5.5 Welding Industry: Heavy and medium welding operations are associated with the risk of Flame, Heat, Sparks and drops of molten metal. Flame protective work wear first became important in the metal industry. Workers in these industries need protection not only from heat and flames, but also from sparks and drops of molten metal.

Fig: 7 Protective Wear during Welding

5.6 Electrical Industry: Flame protective work wear is becoming increasingly important to the electrical industry.

5.7 Others: The Fire retardant fabric also finds an extensive area of application in (Mainly the treated flame retardant fabric are used in most of these application as there are not so frequent washing requirement.)

· All building and constructions need to get fire safety clearance from the fire department. However these clearances are more from the construction perspective rather than furnishing perspective. With boom in retail and real estate there has been rapid emergence of shopping complex, malls, cinema multiplex etc. There is need of fire retardant fabrics in these areas from the security point of view.

· The fabrics used in the interiors of Airlines, Railways and Ships are another key market.

· Office furnishings and hospitals are another key sector.

· The fabrics find application in curtains, sheers, upholstery, stage curtains, blankets, bedding, wall coverings and blinds. However the awareness of these materials is low and there is no regulation on usage of these materials from the safety perspective which hinders the market off-take⁸.

6. Test for Flame Retardancy:

The fire Retardant fabrics need to clear some standard test before making it for use. The type of test to be cleared depends on the application area in which fabric is to be used e.g. 16 CFR 1610 is used for general wearing apparel². NFPA 701 is used for fabric or other materials used in curtains, draperies, table skirts and other window treatment where as NFPA 1971 is used for fire fighting protective ensembles and ensembles element that include coats, trousers, coveralls, helmets, gloves, footwear and interface component. If the clothing is used for the protection against molten metal splashes then EN 373 test needs to be considered. The test to determine the critical oxygen content or LOI is ASTM D2863. The other standard tests used for the fire retardant textiles are: 16CFR1615/1616, EN 531, EN 533, BS 5852/5438, IS 11871, ISO 11613, ISO 6940/6941, ASTM D 1230, ASTM D 6413-08 and ASTM F 1506.

7. Conclusion:

Now a day’s fire retardant clothing are found to be used in different areas as we have found. The fabric should provide protection against flame, heat and molten-metal splashes to be used as fire retardant clothing. The market for fire retardant clothing is getting expand, so there is a lot of scope to flourish fire retardant clothing in this new generation. As now-a-days the safety of peoples at work place and also the protection of property are of prime importance. These types of fabrics are used commercially in domestic purposes, defense purpose and many research applications. The fire retardant clothing which are made by coating of fabric with fire retardant agent are more economical as compare to fire retardant clothing made by using inherent fire retardant fiber. However the coated fire retardant fabric tends to lose their fire retardancy after certain washes. The fire retardant clothing find their application in many areas including work wear for various industries (Oil, iron, steel, Metal, Chemical, Welding and Electrical) to Fire Fighter’s Suit and furnishing fabric used in home, office, buses, trains, cars and air craft. These fabrics are used against life threatening hazards so one must be very much cautious about the new developments or a new products and testing should be done prior to adopting new products.

8. References:

1. “Protective Clothing”, by Pushpa Bajaj & A K Sengupta. Textile Progress, Vol 22, No 2/3/4.

2. Handbook of Industrial Textile: Safety and Protective Textile by S. Adanur pp 415-468

3. Information on http://ncrb.nic.in/

4. Handbook of Technical Textile: Heat and Flame Protection by Pushpa Bajaj, pp 223-259 and Textile in Defence by Richard A Scott, pp 425-458.

5. High Performance fiber by JWS Hearle: Aramids by Serge Rebouillat, pp 23-61 and Thermally Resistant Fiber by A Richard Horrocks, Hans Eichhorn, Hasso Schwaenke, Neil Saville, and Charles Thomas pp 281-324.

6. Indian Journal of Fiber and Textile Research Vol. 32, September 2007, pp 306-318, Inderjeet Kaur, Vibha & Rajneesh Sharma.

7. Information on http://www.technotex.gov.in

8. Baseline survey of the technical textile industry in India, March 2009, IMaCS Analysis

9. The Indian Textile Journal “Application of protective clothing in textiles” by : M Parthiban and M Rameshkumar, May 2007

10. Flame Retardants for Plastics and Textiles: Practical Applications By Edward D. weil Sergei V. Levchik

11. Fire Retardants Materials By AR Horrocks and Dennis Price pp 128-178

12. Information on http://ehow.com/about_7371432_history-flame_retardant-clothing.html

13. Defence Science Journal, vol. 58, No. 4, July 2008, pp 451-459, “Nanotechnology and protective Clothing for Defense Personnel” By: G. Thilagavathi, A.S.M. Raja and T. Kannaian

14. Industrial Textile Association, USA “An Overview of Protective Clothing- Markets, Materials, Needs”: By William C. Smith

15. EFRA European Flame Retardants Association- Making Textiles safer against fire, May 2007.

16. Environmental Aspects of flame Retardants, By: Dr. Heinz Hofer, Osterreilaisches Forschungszentrum Seibersdorf

17. Current Challenges for advanced fire proof / fire resistant, composites and related materials-general Issues By Dick Horrocks, University of Bolton.

18. White Paper on Formulation of Regulations in respect of Safety Industrial Work Wear (Heat and Flame), Draft Report Prepare by : CoE (Protech), NITRA

19. Engineered garments for fire protection by : Dr. Hireni Mankodi and Mehul Pancholi www.fibre2fashion.com