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Ecofriendly Processing of Textiles
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 2 (2015) 1776 – 1791
4th International Conference on Materials Processing and Characterization
Ecofriendly Processing of Textiles a
Bikash Jena,b Bishnu Priya Das,cA. Khandual*, dSanjay Sahu&e Lingaraj Behera c Dept.
a,b NIIFT, Bhubaneswar, Odisha, India-751003 of Textile Engineering., CET,Bhubaneswar,Odisha, India-751003 dColorband Dyestuff (P). Ltd., Mumbai e Chemistry Dept., Sambalpur University, Odisha
Abstract In this the world, though it the major employment generator, the textile industry is considered as ecologically one of the most polluting industries [2]. The issues which make the life cycles of textiles and clothing unsustainable are the use of harmful chemicals, high consumption of water and energy, generation of large quantities of solid and gaseous wastes, huge fuel consumption for transportation to remote places where textile units are located, and use of non-biodegradable packaging materials. Chemical processing of textiles ranging from preparatory processing to dyeing and finishing majorly add its value for fashion and function. It is a matter concern that these processes use water, energy, and chemical intensive and cause serious environment hazard. Thus, global awareness on environmental demands natural fiber-based textiles, natural dye and finishes are gaining momentum in academic, research and industrial research. We discussed here various eco-friendly processes emerging in this area. © 2014Published The Authors. Elsevier © 2015 by Elsevier Ltd.Ltd. All rights reserved. the 4th International on Selection andpeer-review peer-review under responsibility ofconference the conference committee members ofInternational Selection and under responsibility of the committee members of the 4th conferenceconference on Materials ProcessingProcessing and Characterization. Materials and Characterization. Keywords:Eco-friendly, Scouring, Bleaching, Mercerisation, enzymes, BOD
1. Introduction Levinson Elsa [1] of Stockholm University has conducted an important survey to see if consumers have a willingness to pay extra for an environmentally friendly garment or the garments those are produced by environmental friendly process. He has reported that 89% of the respondents expressed their willingness to pay extra to make sure the garment they buy is eco-friendly. In fact, the median amount they are willing to spend is around 65 SEK( swiss currency) extra. There is n increasing trend in demand of organically produced cotton garments which are expanding in global cotton market for niche product. * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address:[email protected]
2214-7853 © 2015 Published by Elsevier Ltd. Selection and peer-review under responsibility of the conference committee members of the 4th International conference on Materials Processing and Characterization. doi:10.1016/j.matpr.2015.07.020
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In this the world, though it the major employment generator, the textile industry is considered as ecologically one of the most polluting industries [2]. The issues which make the life cycles of textiles and clothing unsustainable are the use of harmful chemicals, high consumption of water and energy, generation of large quantities of solid and gaseous wastes, huge fuel consumption for transportation to remote places where textile units are located, and use of nonbiodegradable packaging materials. Chemical processing of textiles ranging from preparatory processing to dyeing and finishing majorly add its value for fashion and function. It is a matter concern that these processes use water, energy, and chemical intensive and cause serious environment hazard. Thus, global awareness on environmental demands natural fiber-based textiles , natural dye and finishes are gaining momentum in academic, research and industrial research. [3] The textile industry uses vegetable fibers such as cotton, animal fibers such as wool and silk, and a wide range of synthetic materials such as nylon, polyester, and acrylics. The production of natural fibers is approximately equal in amount to the production of synthetic fibers. Polyester accounts for about 50% of synthetic. The stages of textile production are fiber production, fiber processing and spinning, yarn preparation, fabric production, bleaching, dyeing and printing, and finishing. At the Each stage wastes generates, which is injected to the environment, because of that there is deterioration of environmental conditions. Depletion of the ozone layer, global warming, rapid disappearance of forest, pollution of water, noise and air etc. are the various problems arises due to the industrialization development. In the past few years, garment processing has become increasingly popular and exports of garments from India have been increasing with leaps and bounds every year. This has created a very healthy atmosphere for the growth of garment processing in our country. The majority of garments exported are cotton based. But the textile processors have come in for a lot of criticism over the last decade for its association with toxic chemicals and the occasional environmental horror story has stained its image. Processing is a term used to describe a wide range of preparation, coloration and finishing techniques performed on the garment. This is clearly identified as having a potentially adverse effect on the environment. Hence for today’s textile processor it has become absolutely necessary to take into consideration the ecological aspects in production of certain quality of garment. Alternatively garment dyers, printers and finishers are attempting to reduce the environmental impact of their processes and it is this area which is the subject of this article. 4 2. Eco-Friendly Processing: Definition With rapid industrialization and urbanization, coupled with the general tendency to assault nature by indiscriminate throwing of waste into the environment, there is a general deterioration of environmental conditions. Depletion of the ozone layer, global warming, rapid disappearance of forest, pollution of air and water, noise, dust, toxic gases, hazardous materials, etc. pose threat to the quality of life and all aspects of health and safety. Our natural resources have only limited ability to assimilate pollution due their restricted self-purification capacity. Hence a time has come to apply effective controls to regulate what and how much should be discharged, dumped or emitted in the environment.1 Garments are indeed our “second skin” and hence the customer is worried whether he is putting himself in contact with the “toxins in clothing”. Thus the need of eco-friendly processing of garment arises, generally referred as “eco-textile”.5 The word ‘eco’ is short for ecology. Ecology is the study of the interactions between organisms and their environment. Therefore ‘eco’ friendly (or ‘ecology friendly’) is a term to refer to goods and services considered to inflict minimal or no harm on the environment. There is really no such thing as a 100% eco friendly piece of clothing. This is because all clothing takes water (to grow the fiber which makes the fabric) and energy (to make the fabric and the garment).When we talk about eco friendly textiles, we are talking about those companies which make it a point to minimize this damage by using fibers not grown or produced with damaging chemicals, and fabrics not colored with harsh dyes and paints. In summary, ‘Eco’ friendly clothing might mean:-Clothing made of fibers such as organic cotton and hemp.-Clothing that has been organically dyed with vegetables.
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Eco-textiles are those that have been produced with the lowest possible negative impact on the environment. All aspects from origination right through to disposal have to be taken into account. The processor must be able to identify, understand and measure a lot of parameters and their relations. 6 Why eco? The main environmental issues associated with textile industry arise from emissions to water. The changing face of environmental legislation is causing serious problems for industries many and the textile industry is no exception. A new parameter that today increasingly vital is ecology. The logo of eco-labeling is becoming an increasingly important factor. Worldwide environmental problems associated with the textile industry are typically those associated with the water pollution caused by the discharge of untreated effluents and those because of use of toxic chemicals especially during processing. These chemicals can harm consumer if retained in the fabric. There is always a danger to the workforce in the industry via air, direct contact, accidental exposure etc. Hence the substitution of the non eco-friendly auxiliaries will only serve towards the consumer and the environment. The eco norms are also becoming stringent these days. Thus it is increasingly becoming necessary for the industry to adapt the novel trends which are benevolent to the nature. The Garment Industry And The Environment The garment industry occupies a unique place in our country. One of the earliest to come into existence in India,it accounts for 14% of the total Industrial production, contributes to nearly 30% of the total exports and is the second largest employment generator after agriculture. In the new competitive environment after the garment quota regime of quantitative import restrictions under the multi-fibre arrangement (MFA) have come to an end on 1st January, 2005, developing countries with both textile and clothing capacity may be able to prosper. Thus if the Indian garment industry has to compete successfully it has to immediately adopt positive measures to control all the stages of production to comply with the mandatory requirements of the foreign buyers. Garments are a result of a complex series of manufacturing processes, in the course o which an extremely diverse range of chemicals may be used. Some examples of these hazardous chemicals are 7:x Pesticides. x Pentachlorophenol. x Acidiy/Alkalinity (pH) x Dyestuffs. x Dye Carriers (Chloro organic). x Loose Dye. x Volatile Compounds. x Odours. x Formaldehyde. x Extractable Heavy Metals. x Flame Retardants. x Biocides. 2.1 Causes Of Pollution Due To Garment Processing 1.
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Use of chemical like potassium dichromate, sodium hydroxide or peroxide, sodium hypochlorite in the preparation process of desizing, scouring and bleaching with their associated wash-off stages produce heavy biological oxygen demands (BOD) in the effluent. Chlorine is prohibited for bleaching because of generating halogenated organic substance of which some are suspected to be carcinogenic e.g. chloroform. Dyeing and Printing: a. Use of azo dyes releasing harmful amines: - The amines, which are released from azo dyestuff in preference of a reductive chemical medium or by enzymatic action, exert their effect by causing DNA damage, which leads to tumor formation. The reduction
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b. c. 3.Finishing:
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products are electrophonic and covalently bonded to the nucleic acid of DNA resulting in DNA damage and hence inducing cancer. Use of dyes containing traces of heavy metals. Use of formaldehyde.
Use of formaldehyde as an easy care finish: Formaldehyde is a toxic chemical, skin irritant and sensitizer. Controversial animal inhalation tests with very high concentration have shown that it is a nasal carcinogen to rats and mice. b. Use of stiffeners containing plasticizer such as tributyl/triphynyl phosphate. c. Use of optical brighteners and softeners cause sensitizing effect. d. Application of flame retardant chemicals, manufacture and its transportation. Use of stain removers containing chlorinated products in garment manufacture. High energy and water consumption during processing. 8 a.
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2.2 Various Terms Used In Eco-Friendly Processing The processor must be aware of certain terms and quantities used while determining the eco-friendliness of garment processing. Below are the three methods used to determine the amount of water pollution: I. Biological oxygen demand (BOD) BOD, mg/litre = (D1 – D2)/V Where D1 = Initial dissolved oxygen D2 = Dissolved oxygen after five days V = Volume of sample used II. Chemical oxygen demand (COD) COD, mg/litre = (B – A)*N*8000/V Where A= volume of ferrous ammonium sulphate solution used for titration in ml B= blank titration reading in ml N= normality of ferrous ammonium sulphate solution V= sample volume in ml 6 III. Adsorbable organic halogen (AOX) In this method, the organic substances are adsorbed from the sample onto (halogen free) activated charcoal. The charcoal is then burnt in a stream of oxygen and the hydrogen chloride formed is determined quantitatively. This parameter includes a wide range of compounds like volatile chlorinated hydrocarbons, plastic (PVC), toxic chlorophenols, etc.7 ECO-LABELS: Eco labels are fast assuming great significance for the successful export and market promotion in apparel textile industry. In addition to the requirement to the individual firms there are a large number of trademarks and labels for textiles, made available by associations, institutions and service companies of textile industry. Eco-labels are used as tools to identify green products. 11 Criteria for awarding of eco-label basically consist of: x General requirements of eco-toxicological and health aspects of chemicals used at various stages of processing x The demand that certain harmful substances are absent or present below the specified limits on marketed garment x Restrictions on the environmental impact of discharge in water/air during processing x Quality requirements as regard the fastness of the color and other performance Some of the popular eco-labels are The EU Eco-label, OKO-TEX Standard 100, Eco Mark, Green Seal, Blue Angel, etc.
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ISO 14000 The ISO 14000 series of International Standards have been designed to address those issues confronting environment today. The main goals of ISO 14000 are: a) Conservation of natural resources. b) Reduction and abatement of waste and emission. c) Continuous improvement in environmental performances. d) Efficiency in operation by use of best available technology. e) Compliance to National and International environmental laws and convention. 12 2.3. Strategies for eco-friendly processing: Any systematic approach to shift average production towards clean production should undergo the following steps: AVOID: To ‘avoid’ is to drop a procedure or product in favour of dramatically improving the environmental situation. REDUCE: This can be achieved by reduction of pollutant load, exhaustion and fixation of dyes close to 100 %( ideal) and saving of water and energy. REUSE: Reuse of the dyebath is an essential consideration under the pressure of dwindling resources. This has now become a reality due to inclusion of new auxiliaries, modern filter technology and spectrophotometers that measure the content of the dye in the dyebath accurately.
RECYCLE: The recycling of natural fibers is possible but is limited due their natural degradation. Synthetic fibers can be recycled by melting down and regranulating with or without the addition of fresh granules. This is probably the most acceptable to‘green’ organizations but is limited owing to lack of uses for the material recycled. 8 3. Garment Processing: Considerations The term ‘garment processing’ may be perceived as preparation, dyeing, printing and finishing operations performed on apparel that has been fully made and is ready for sale immediately after these operations. Now it would be interesting to ask why we bother to process garments at all? Pre-dyed yarn for knitwear and hosiery and pre-dyed fabric for woven goods would sometimes seem to be an easier option. However, there are several good reasons why garment processing is advantageous. ADVANTAGES: x Handling of smaller lots economically x Enables various special effects to achieved x Distressed look can be effectively imparted x Unsold light shades can be converted into medium and deep shades x By the time the garment has been in a boiling dyebath and then tumble dried, it will have adopted its lowest energy state and will not suffer further shrinkage under consumer washing conditions x Latest fashion trends can be effectively incorporated by immediate feedback from the customer But advantages are also associated with disadvantages, which are:
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x High cost of processing x A little complicated dyeing x Garment accessories like zips, buttons, etc impose restrictions. 13,14 GARMENT PROCESSING IS INVARIABLY A BATCHWISE PROCESS In garment processing the accessories play very important part that need to be considered: SUPPORT MATERIALS: These are important to provide shape, stability, increase retention of the original appearance and conceal garment interiors. These include linings, interlinings, shoulder pads, tapes, etc. Compatibility factors to be considered are they should have soft hand, flexibility, bulk and should be stable to heat and pressure. SEWING THREAD: Sewing is the most value adding stage in the entire garment manufacturing process. This is where the conversion of fabric cut pieces to garment takes place by means of stitches and seams. A stitch is the configuration of the interlacing of sewing thread in a specific repeated unit and seam is a line where two or more fabrics are joined. METAL COMPONENTS: Garment design incorporates certain metal components such as zips, buttons, etc. which can present difficulties to the garment dyeing operation 15,16. 4. Garment Processing Machinery Garment to be processed have to be carried out in specialized machines. Various types of machines have been developed to handle hundreds of individual articles of different shapes and sizes. The availability of equipment with high temperature capability further expands the potential of garment processing for both polyester and its blends. The machines likely to be used in garment processing are: 4.1 Hydro-Extracter Or Centrifuging Machine
Fig.1.Hydro - Extracter14,17 Hydro-extractors are ideal machines for extraction of water or liquid from garments. Machine has a central rotating (perforated) basket shell made of stainless steel or any other material lined rubber line FRP (Fiber reinforced plastic) covered with safety covers. The bottom part is of conical shape and is of heavy casting. Conical shape increases the centrifuging action and extracts the water from the garments. Machine is mounted on a triangular base and drive is given to basket by means of motor and V-belts. It rotates with a speed of around 650 – 1400 rpm. High-speed models are also available which gives much drier product in less time. Maximum permissible load varies from 70 – 400 kg. Thus water is removed from garments by exerting centrifugal force on garments. Centrifugal force will create tension in garments and thus RPM must be selected according to the strength of the fiber.
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Fig-2 Horizontal Paddle MachineFig. 3 Lateral Oval Paddle MachineFig.4 HT Paddle Machine
4.2 Paddle Dyeing Machine: These are very versatile and are generally of three types – I.Horizontal Paddle Machine This machine consists of curved back like lower section, which contains the material and the dye liquor. The goods are moved by a rotating paddle, which extends over the width of the machine. The paddle is just about half submerged in the liquor and moves the dye liquor evenly over the entire width of the back. The design of the paddle causes material to move upwards and downwards through the liquor. The material and the liquor move in an axial circular movement. II. Lateral Oval Paddle Machine Here the liquor flow is improved by constructing an oval tank. In the middle of this tank is a closed oval island around which the liquor is kept in motion. The paddle moves in lateral direction and is fully submerged in the liquor. III. HT Paddle Machine The operating principle is same as that of horizontal paddle machine. Here the liquor receptacle is cylindrical and is so designed that dyeing can be carried out at temperatures upto 140 0C.
Fig.5 Drum Dyeing Machine. Fig.6 Rotary drum dyeing machine
4.3 Drum dyeing cetrifuging machine: This machine is also called as “multipurpose drum machine” since it can perform all wet processing operations successfully with automated programme control. This machine is distinguished by the fact that it permits rapid loading and unloading, can operate with a very low liquor ratio and its ability for dyeing at temperatures upto 1400C 4.4Rotary Drum Dyeing Machine: Here a perforated drum is suspended along a lengthwise axis in the horizontal position submerged in the liquor. To ensure good movement of the material the drum is divided into four equal compartments separated by cross perforated dividing walls. The drum is capable of rotating in either direction. The compartments can be loaded individually.
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4.5 Tumble Driers:
After washing or dyeing garments are centrifuged and finally dried. This machine consists of perforated stainless steel drum, which rests on friction wheels. Loading and unloading can be done from front side or from the top of the machine. The suction unit draws the fresh air through the heating element and enters the drum, which is rotating. After drying the garments the air comes out of the machine through exhaust duct. Recently, tumblers are also available with reverse drive and also have automatic temperature control giving constant drying temperature. In modern machines temperature, moisture, air circulation rate, drum speed can be automatically adjusted. The garment processing route involves various stages which will now be discussed taking into consideration their eco-friendly aspect. 5. Garment Preparation One might ask why is it necessary to prepare garment or in that case textile substrate at all ? The answer is – x To remove natural substances such as oils, fats and waxes, pectin, etc. x To remove sizes and waxes applied during weaving x To remove soil accumulation x To achieve good and even absorbency for uniform dyeing x To remove self color of material 5.1 Desizing: Sizes constitute a basic problem for the ecology. In the manufacture of woven and knitted fabrics it is necessary to cover the yarn with a transitory finish, which is easily eliminated by water. This finish may amount to 20% of the weight of the fabric and has to be removed prior to further chemical processing. An analysis of dye house waste water shows the magnitude of this problem. Based on the measurement of the COD, it was demonstrated that 57%of the waste water load comes from sizes. Desizing is done to remove the various sizes applied to the fabric during sizing. Common sizes for cotton are starch, carboxyl methylcellulose, polyvinyl acetate, etc which are applied along with lubricants and waxes. Desizing is carried by two methods, the former being the popular one. I. BIOLOGICAL DESIZING This is carried using α-amylase enzyme. This is much safer than the oxidative desizing as the α-amylase enzyme attacks only the size and not the garment. Efficient desizing with α-amylase requires: 1. Thorough impregnation of fabric with enzyme solution 2. A digestion period for the conversion of starch into soluble dextrin 3. Proper temperature 4. Proper pH 5. Efficient washing/rinsing to remove the degraded starch II. OXIDATIVE DESIZING This typically employs an alkaline, oxidative solution of hydrogen peroxide or persulphate. Oxidative desizing is much more versatile than biological desizing as it removes a wide range of sizing agents. But these can damage the garment if not carefully controlled. ,18,19 5.1.1 ECO-FRIENDLY PROCESS In general about 50% of the water pollution load is due to the desized wash water which has a high BOD and COD. This can be minimized by: 1. Selection of sizes: The most commonly used sizing agent is starch whose decomposition products have a very high BOD and can no longer be reused. 2. Recovery and reuse of sizing polymer: In partial recycling, easily soluble sizes such as modified starch, polyvinyl alcohol, and polyacrylics are selected and the first, concentrated wash liquor, is isolated and
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only the other dilute washes are let off in waste water, thus reducing the pollution load by 50%. The isolated first wash water is reused by adding a calculated fresh quantity of sizing polymer. 20 5.2 Scouring: Scouring is typically performed in an alkaline solution and high temperature environment. The removal of natural impurities is based upon saponification at high pH. The removal of natural impurities can be done in a single process or can be combined with desizing and/or bleaching. The use of sequestering and reducing agents can be avoided when softened water is used. Impurities (natural as well as added) are totally removed in scouring process. This makes the fabric more absorptive without undergoing any chemical or physical change. 21 The main processes occurring during scouring are 1) Saponifiable oils are converted into soaps. 2) Proteins are hydrolysed into soluble degradation products. 3) Simpler ammonia compounds are hydrolyzed to ammonia. 4) Pectose and pectin are changed into soluble salts of pectic or metapectic acid. 5) Unsaponifiable waxes and oils are emulsified by the soluble soaps formed from saponifiable oils. 6) Dust particles are removed and held in stable suspension form in the kier liquor by the detergent present. 5.3 Bleaching: Bleaching is a process which removes the intrinsic color of the material, thus making it whiter in appearance. Oxidants typically used in bleaching are hydrogen peroxide and sodium hypochlorite. After scouring, cotton becomes more hydrophilic. However, the original colour stays unchanged due to coloured matter that cannot be completely removed by washing and alkaline extraction. When the material has to be dyed in dark colors it can be directly dyed without need of bleaching.18 Three chemicals are commonly used: 1) Hydrogen peroxide (H2O2) 2) Sodium hypochlorite (NaClO) 3) Sodium chlorite (NaClO2). The bleaching process is mainly divided into two categories. Such as: I. PEROXIDE BLEACHING II. HYPOCHLORITE BLEACHING 5.3.1 Eco-Friendly Process The scouring and bleaching processes have been identified as highly polluting and energy intensive. Scouring assistants containing chlorinated hydrocarbons, solvent emulsion are highly toxic. Hypochlorite bleaching is considered as main source of AOX and also results in formation of chloroform by reaction between chlorine and organic alcohols. Hence a greener process is badly required here which can be achieved using following methods: I. COMBINED SCOURING/BLEACHING: The bath is set with .5-1% alkali stable surfactant, 2-4% caustic soda flakes, 1-2% non-silicate stabilizer and 3-5% H2O2. MLR is kept at 1:10. Material is entered at room temperature and then the temperature is further raised to 85-900C. the material is treated for 40-60 min. Rinse the material thrice in water of gradually decreasing temperature. II. ENZYME APPLICATIONS: The discovery of novel, powerful alkaline pectinase promises to provide an eco-friendly, cost effective means to prepare cotton substrate. This unique pectinase functions well under slightly alkaline conditions in the presence of chelating and selected wetting agents. A combination of pectinase and cellulase significantly improves water wetting and retention properties, to level similar to those of commercially scoured cotton. Amongst other benefits listed are shorter washing process, savings in water consumption and increase in the efficiency and reproducibility of subsequent dyeings.19,22
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MERCERISATION Mercerization is the treatment of pure cotton fabrics or yarn with a strong caustic soda solution (usually 280-300 gpl) to improve strength, dye substantivity, strength and smoothness. The effects of mercerization 21 x
Improved luster , Increased ability to absorb dye,Improved reactions with a variety of chemicals ,Improved stability of form ,Improved strength/elongation & Improved smoothness etc.
Ways to minimise pollution in mercerising x Dilute alkali from mercerizing should be reused in scouring, bleaching or dyeing operations, so that discharges from alkaline treatment can be minimised, resulting less polluted effluents. x Liquid ammonia is a low pollution substitution for conventional mercerisation (NaOH). x
Heavy cotton fabrics treated with liquid ammonia require less dye for a given depth of shade, and consequently contribute to pollution abatement due to using less chemical for the same requirement.
Alkali should be recovered and recycled or reused after regenerative treatment to remove dirt (coagulation, flotation, microfiltration, nanofiltration) and after concentration. 6. Dyeing: The general dyeing technology for garments is the same as for standard exhaust procedures, except for pigment dyes. Here important factor to be considered are the accessories used in garment manufacturing. Adequate penetration of dye liquor into garment seams and a good balance between different fabrics and sewing threads used must be achieved. Garment dyeing is carried out as a batch process with a typical lot weight of 100 – 200 kg in the machineries discussed earlier. 18 6.1 Dyestuff Selection
While garments are made largely of 100% cotton, other fibers such as acrylic, nylon, wool and polyester/polyester blends can be processed. The table below illustrates dye classes available for different fibers. FIBER DYE CLASS Acrylic Cationic Cotton Direct Reactive Vat, Pigment Sulphur Nylon Acid Premetallized Polyester Disperse Wool Acid Premetallized Reactive The dyeclass selection will follow certain criteria: x What are the fastness requirements? x What are the cost requirements? x What is the shade range desired? What performance requirements will be needed because of the type of garments, machine restrictions, and dyeclass needed to meet fastness, cost, and shade demands? 23 6.1.1
Reactive Dyes Fiber reactive dyes are noted for their brightness and high wetfastness properties. Available in a complete range of shades. 6.1.2 Direct Dyes These are generally considered for their economy and short dyeing cycles but have limited wet fastness properties, particularly in heavy shades. 6.1.3 Vat Dyes For high fastness to industrial laundering, or where severe chlorinated water fastness is a requirement, there is a limited use of vat dyes. 6.1.4 Pigments
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Pigments produce bright, fluorescent shades of low wet-fastness properties at moderate cost. The theory behind exhaust dyeing of pigments is “cationization” of the garment. The garment is pretreated with a cationic dye acceptor forming a positive charge. Pigments being insoluble in water are made with additions of anionic surfactants and dispersants and therefore they have a negative charge. This results in deposition of pigments on the garment surface. These pigments are then fixed with a binder and further thermofixed during drying to improve the fastness. 24
6.1.5 Sulphur Dyes Sulphur dyes offer moderate to limited brightness of shade, moderate to low cost and generally lower wetfastness. Sulphurs would be an ideal choice for economic navies and blacks or when dyed garments are to acid washed. 6.1.6 Acrylic Dyeing Cationic dyes on acrylic will offer bright shades with excellent fastness properties. 6.1.7 Polyester Dyeing Disperse dyes for polyester offer wide range of shades, fastness properties, economics, and application flexibility. Polyester is far more difficult to dye than other synthetic fibers and requires either high dyeing temperatures or a carrier. 6.1.8 Nylon Dyeing For nylon, acid or premetallized acid dyes should be considered. Acids offer a complete range of bright shades with excellent leveling and moderate to good wet fastness properties. For improved wet fastness aftertreatment can be included. Premetallized dyes are less bright and have lower leveling properties than acids. However, premetallized dyes would offer improved wet fastness properties without requiring an aftertreatment. 6.1.9 Wool Dyeing Wool may be dyed with acid, premetallized or wool reactive dyes. Acid dyes would offer a complete, bright shade range with good leveling properties and moderate wet fastness properties. For bright, high wetfastness shades, the wool reactive dyes may be preferred.23 6.2 Eco-Friendly Process Of Dyeing Dyeing also commonly called as coloration is associated with significant environmental problems as: x In the manufacture of dyes due to use of carcinogenic intermediates x Discharge of dyes into streams. Azo dyes are readily cleared at the – N = N – bond to produce aromatic amines considered to be harmful. Auxiliaries used like carriers, dye fixing agents, retarders, heavy metal salts, etc. Hence to make dyeing more eco-friendly following strategies would be handy: Selection of dyestuff necessary from the following point of view – x Avoiding use of dyes which can form on reduction carcinogenic amines x Selection of high exhaustion dyes particularly among reactives x Avoiding the use of copper and zinc salts as aftertreatment agents or catalysts or reducing agents x Replacing the halogenated organic carriers with combinations of other carrier types Avoiding the use of chromium salts for the dyeing of acid dyes. 8 6.2.1 Cotton Dyeing x Optimization of fixation and washing off properties resulting in improved wash fastness thus cleaner effluent. High fixation means that very little unfixed dye must be washed off reducing the amount of waste water itself x Use of low salt range of reactives which need only fraction of the salt necessary for all other reactive ranges to ensure adequate exhaustion, fixation and reproducibility. Thus resulting in massive reduction of electrolytes in the waste water. 6.2.2 Polyester Dyeing x Improvement in the formulation of disperse dye to achieve increased dyebath and to decrease the need for carrier use x Producing readily-cleared alkali soluble disperse dyes, which eliminate the need for conventional reduction clearing x Use of low liquor ratios to reduce the effluent volume
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6.2.3 Wool Dyeing x Selection of wool reactive dyes which are metal free x Use of formic acid instead of acetic acid results in a substantial reduction in COD 6.2.4 Role Of Natural Dyes Although the use of natural dyes in the production of eco-textiles is attracting growing attention, their extraction and processing cannot, in general, be regarded as environmentally benign or even eco-friendly. For example, cochineal is extracted from lice by crushing them alive! Practical disadvantages also exist. To dye 1 kg cotton to a medium shade takes 20 g synthetic product such as reactive dye. To obtain the same shade with vegetable dyes requires approximately 1 kg dried leaves, equivalent to 5 – 10 kg freshly picked leaves. Thus even if only a small fraction of fiber to be processed are thus dyed, very large plantations are necessary. Also, mordants are often required to fix them.6 Thus the use of natural dyes only comes with a word of caution and hence the use of synthetic dyes is indispensable. 7. PRINTING Printing is used to show production of design of various colors and pattern on the fabric also called as localized dyeing. Here one or more colors are applied to the goods locally and then developed during steaming. Fabric printing is an age old art but garment printing is of recent origin say a maximum two decades. During the last one decade the technology has changed at a fast pace from its primitive hand operated printing machine to the latest fully automatic microprocessor controlled machine. So far only chest or the back or the sleeves of the garment could be printed but of late complete garment say a T-shirt can be printed with an over all print on both sides of the T-shirt. However sophisticated be the systems used to control the production, a printer will not succeed unless the design and colors appeal to the end user. There are two types of garment printing machines available viz. colossal (round) and oval type. The machines are available with a possibility of printing 4-12 colors and a print area of maximum 30” X 40” for overall prints. Both types of machines have pallets or boards of various sizes to suit the sizes and shapes of the garment. Pallets are necessary to avoid printing on the backside of the garments. A modern machine can print upto 600 garments per hour. The technology used on these machines is screen printing. Most popular colors used in garment printing are pigments, reactives and plastisols. In case of pigment printing it is necessary to use some kind of solvents viz. kerosene or mineral turpentine oil (MTO). 25 7.1 eco-friendly printing x Use of all aqueous system for pigment printing to avoid solvents, which are called as water base. The advantage being freedom from any toxic smell. x Use of automatic weighing systems which are capable of dispensing liquid dyes and even dye powders with minimal release of dust x Wastage of print paste can be reduced by installing return systems that recover much of the paste otherwise lost in supply pipes and from within the screens themselves x Residual paste can be recycled, with the assistance of colorimetric measuring and recipe prediction systems x The ultimate option is to recover the thickening agent from waste paste, this being achieved by the use of an ultrafiltration process; tests have shown that the recovered thickeners showed no degradation. x Continuous preparation of print paste to prevent the preparation of excess print paste. This entails an in-line measurement of the print paste consumption in the printing process. 26,27 8. FINISHING Finishing treatments are important to increase the appeal and usage characteristics of the garment. It assumes considerable significance because of the value addition realized through functional finishing of cotton in garment form to impart desirable properties. Some of the important finishes are discussed henceforth. 8.1 easy care / wrinkle free finishes One of the major shortcomings of cotton garment is its tendency to creasing during wearing and after washing. In order to impart wrinkle free appearance they are treated with cross linking agents. The process is traditionally known as resin finishing which imparts crease resistant property to cotton and keeps the shrinkage under control. The principle benefits in wrinkle free processing in garment form are: x Permanent fixing of creases at desired places
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x The risk of premature cross linking during drying, storage, and transportation is avoided x Puckering of garment seams is minimized There are two methods of garment finishing: 1. TUMBLE METHOD x 2. DIP METHOD 8.1.1 eco-friendly process Majority of cross-linking agents used today are formaldehyde based which are cost effective and efficient. However the release of formaldehyde vapors during processing as well as during storage and consumer use has caused worldwide concern of its impact on human health and environment due to its suspected carcinogenic and well-known dermatitis effects. Some of the approaches to limit problem of formaldehyde release are: x After wash of cured garment x Addition of formaldehyde acceptors or scavengers such as carbohydrazide, urea to the finishing bath x Application of 10-30% urea solution with 5-10% add-on by atomized spray technique using BASF fog chamber x Modification of DMDHEU with alcohol to produce etherified DMDHEU to decrease formaldehyde release x Treatment of DMDHEU with diethylene glycol or 2,3-propanediol. 29,30 8.2 softeners Garments are usually comfortable to wear if they are soft to touch. Chemical pretreatments remove natural cotton waxes rendering cotton harsh to handle. This is made worse after wrinkle free finishing. To compensate this; softeners are widely used. There are many kinds of softeners available which are classified as anionic, cationic, nonionic, amphoteric and reactive. Most famous being silicone softeners. Silicone is a general term that refers to class of man-made polymers based on the frame work of alternate silicone and oxygen bonds with organic substituents attached to silicones. Methyl group is the most important of organic substituents used in commercial silicones. 8.2.1 eco-friendliness Pdms becomes part of thewastewater stream in the form of tiny dispersed droplets and attach to suspended solids. Because non-volatile PDMS fluid is essentially insoluble in water, these materials become a minor component of the sludge. Though PDMS materials are highly resistant to biodegradation they break down into lower molecular weight products during soil contact. The degradation products are susceptible to biological decomposition eventually oxidizing to natural silica. 30 8.3 Bio Finishing For Denims Many garments especially jeans commonly referred as denim are defaced after machining to give it a faded look. The traditional methods involve pressure cooking of the jeans in presence of sodium hydroxide or an oxidizing agent. Moreover pumice stone has been used to achieve the same effects. Hence is also called as “stone wash” effect. This method has two main drawbacks: 1. It causes damage to the machine 2. Occurrence of pumice dust in the environment and in the garment creating a harsher handle. 8.3.1 Eco-Friendly Way: Enzyme technology now offers a novel process to achieve the same “stone wash” effect using cellulose enzyme which is generally referred as bio washing or bio finishing or in that case even as biostoning. Cellulases are multicomponent enzyme systems that are commonly produced by fungi and bacteria. Neutral cellulases are preferred for biostoning of indigo dyed denim trousers and other garments. Along with their eco-friendly advantage they also provide reduced pilling, durable soft handle and increased gloss or luster. 30,31 9. The Future of Garment Processing The current trend in clothing to the more casual and worn out look is proving to be very promising for garment processors. As has been shown, casual and distressed looks are better produced by garment processing and in some cases can only be achieved in this way. The chain stores are looking to shorter, more frequent seasons to stimulate sales. Already companies are changing colors and styles every few weeks, and the type of quick response is ideally suited to garment processing.
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Even the latest developments in electronics and information technology can be used to advantage for garment processing. It is now possible to develop color palettes using the Imagemaster system, which allows manufacturers to show ranges of new clothes on a screen without any physical garment manufacture or processing having taken place. Production can then commence, using garment processing wherever possible to replace stock quickly as it is sold.13,20 10. Consemer Acceptance While our industry is still far from perfect, and it will take a huge shift in consumer thinking to change wasteful consumption, this assignment gives us great hope that there are industry leaders out there pushing for a new industrial revolution. One that goes back to quality, not quantity, and encourages thoughtful manufacturing processes, as well as ecological awareness. There has been a significant increase over the past few years in the use of eco-labels, i.e. environmental labels attached to a variety of products to attract the attention of consumers about the environmentally positive features of the products. Generally these labels are voluntary and mostly used for the promotion of the products on the basis of their environmentally friendly characteristics. In the case of textiles and clothing there are for the time being no eco-labels the use of which has been enforced by mandatory rules. To enhance awareness about the environmental impacts of products, the Ministry of Environment and Forests (MoEF), Government of India (GoI) has initiated a sheme in 1991,which is basically a scheme of labeling the eco-friendly products .It is known as “Eco mark” scheme and aims at easy identification of eco-friendly products.The scheme is based on a “cradle to grave” approach and takes into account the impact of a product from the raw material extraction, to manufacturing, and to final disposal. an earthen pot has been chosen as a logo for the eco-mark scheme. There are different eco-labeling schemes both in developed and developing countries. The following list includes some of the government sponsored and some private labeling schemes: 32 Government Sponsered Scheams: x Angel (D), Eco Mark (JPN), x Environmental Choice (CND), x White Swan (Nordic Countries), x EU, Eco-Mark (India), x Green Label (Singapore) x Green Seal-(USA) x ToxProof-TUV (GERMANY) xFlower(EU) 11. Success of Eco-Friendly Processing For solving ecological problem a total commitment from top management to technologist and quality personnel is necessary. The chart shown below could be a guide to successful eco-friendly processing:7 Environmental policy x Commitment to continual improvement and prevention of pollution x Commitment to complying with relevant legislation and other requirements x Setting environmental objectives an targets
x x x x
Planning Environmental aspects Legal and other requirements Objectives and targets Environmental management programs
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x x x x x
x x x
Implementation and operation Structure and responsibility Training, awareness and competence Communication Operational control Emergency preparedness and response
Checking and corrective action Monitoring and measurement Nonconformance and preventive action Records
Management review Key to maintaining commitment throughout the organization
12. Conclusion The environment is nothing but conditions surrounding us. With respect to the human beings, it covers everything in the biosphere. Oceans, fresh water, atmosphere, rocks, soil, organism & so on. No doubt that the industrialization is must for the development & better standard of the living but it is detrimental to the overall quality of the life due to encroachment on the natural resources & injection of the pollutant in the environment. Along with the rapid increase in industrialization and the ever burgeoning population the production of textiles is bound to increase many folds. Thus, the already severe impact on the environment will get much more intense in the future. Also, as the public’s awareness and concern for the environment continues to increase, so the pressure on the garment processor for him to use eco-friendly processes will intensify. This needs a fundamental change in the attitude of the management and the technologists to take corrective actions for a brighter future of our garment industry and for exports in particular. References Levinson, Elsa, Thesis, Stockholm Universe, “Green clothes: A surveyof people’s willingness to pay for environmentally friendly clothes”, 2010. http://www.diva-portal.org/smash/record.jsf?pid=diva2:350380 2. A. K. Roy Choudhury ed. S.S.Muthu, Environmental Impacts of the Textile Industry and Its Assessment Through Life Cycle Assessment ; Roadmap to Sustainable Textiles and Clothing ,Textile Science and Clothing Technology Spinger,1-39, 2014 3. Kartick K. Samanta, S. Basak,S. K. Chattopadhyay, ed. S.S.Muthu, Roadmap to Sustainable Textiles and Clothing ,Textile Science and Clothing Technology, Spinger, 263-287, 2014 4. Mehta, K. H., A Journal of "Developments in environmental legislation in India with regard to dyes and chemicals industry." Colourage” 40, 49,1993 5. Prof.Dr.J.Mecheels , Melliand Textilber,74,(7), 159, 1994 6. G.Horstmann, Journal of Society of Dyers and Colorists ,Textile Technology Digest, publisher Institute of Textile Technology , 52, I7-12,1995 7. J.J.Shroff, Colourage, 47,17,2001 8. U.Sewekow, Textile Chemist and Colorist ,Publisher American Association of Textile Chemists and colorist, 28 (1) ,21-27,1996 9. J.Hilden, International Textile Bulletin, 40, (3),4, 1994 10. Prof.W.B.Achwal, A Indian Textile Journal,Colourage,, 99,1992 11. B.J.McCarthy and B.C.Burdett, Review of Progress in Coloration, 28 , 61,1998 12. M.Joshi ,Indian journal of “Fabre & Textile Research”, Environmental Management Systems For The Textile Industry ,28, 33-38, 2001 13. G.Cawood and J.Scotney, Review of Progress in Coloration, 30 , 35,2000 1.
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14. Mazadul Hasan ,Textile Engineer at INTRAMAX ,”Garment dyeing Machine”-slide Share, 2014 ,www.slideshare.net/sheshir/garments-dying-machine 15. “DOC” Cheek, American Dyestuff Reporter, 76, (8),74, 1987, 16. V.Budhiraja and Dr.Ela Dedhia, “Book of Papers” NCUTE, 113,2001 17. R.S.Bhagwat, Handbook of Textile Processing Machinery, Color publications, 1983 . 18. J.A.Bone, P.S.Collishaw and T.D.Kelly, Review of Progress in Coloration, 30,41, (2000) 19. J.N.Etters, B.D.Condon, P.A.Hussain and N.K.Lange, American Dyestuff Reporter,88, (6), , 19, 1999 20. Prof.W.B.Achwal, Colourage, 99, 1992 21. V.A.Shenai, “Technology of Bleaching and Mercerising”, Sevak Publication,3, 23,80,188,243,299, 2003 22. N.Duran and M.Duran, Review of Progress in Coloration, 30,41,2000 23. N.E.Houser, American Dyestuff Reporter, 80, (5), 18,1991, 24. D.C.Gore and J.H.Settle, American Dyestuff Reporter, 83,(5), 24, 1994, 25. D.K.Jain, Colourage, 43, (3), 23,1996 26. T.L.Dawson and C.J.Hawkyard, Review of Progress in Coloration, 30, 7, 1999 27. E.Roelofs and Tebodin.B.V, Melliand Textilber, 80,(6), 126, 2000 28. E.Menezes, Colourage, 48,(8) , 29, 2001 29. J.R.Provost, Journal of Society of Dyers and Colorists, 108 , 260, 1992 30. Dr.R.B.Chavan, “Book of Papers” NCUTE, 198,2001 31. D.L.Shah and Dr.A.Kulkarni, Man-made Textiles in India, 6, 1990 32. HJ Gam , A Journal of Fashion Marketing and Management , "Are fashionǦconscious consumers more likely to adopt ecoǦfriendly clothing ?", Department of Family and Consumer Sciences, : An International Journal, 15, (2), 178 – 193, 2011.
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ScienceDirect Materials Today: Proceedings 2 (2015) 1776 – 1791
4th International Conference on Materials Processing and Characterization
Ecofriendly Processing of Textiles a
Bikash Jena,b Bishnu Priya Das,cA. Khandual*, dSanjay Sahu&e Lingaraj Behera c Dept.
a,b NIIFT, Bhubaneswar, Odisha, India-751003 of Textile Engineering., CET,Bhubaneswar,Odisha, India-751003 dColorband Dyestuff (P). Ltd., Mumbai e Chemistry Dept., Sambalpur University, Odisha
Abstract In this the world, though it the major employment generator, the textile industry is considered as ecologically one of the most polluting industries [2]. The issues which make the life cycles of textiles and clothing unsustainable are the use of harmful chemicals, high consumption of water and energy, generation of large quantities of solid and gaseous wastes, huge fuel consumption for transportation to remote places where textile units are located, and use of non-biodegradable packaging materials. Chemical processing of textiles ranging from preparatory processing to dyeing and finishing majorly add its value for fashion and function. It is a matter concern that these processes use water, energy, and chemical intensive and cause serious environment hazard. Thus, global awareness on environmental demands natural fiber-based textiles, natural dye and finishes are gaining momentum in academic, research and industrial research. We discussed here various eco-friendly processes emerging in this area. © 2014Published The Authors. Elsevier © 2015 by Elsevier Ltd.Ltd. All rights reserved. the 4th International on Selection andpeer-review peer-review under responsibility ofconference the conference committee members ofInternational Selection and under responsibility of the committee members of the 4th conferenceconference on Materials ProcessingProcessing and Characterization. Materials and Characterization. Keywords:Eco-friendly, Scouring, Bleaching, Mercerisation, enzymes, BOD
1. Introduction Levinson Elsa [1] of Stockholm University has conducted an important survey to see if consumers have a willingness to pay extra for an environmentally friendly garment or the garments those are produced by environmental friendly process. He has reported that 89% of the respondents expressed their willingness to pay extra to make sure the garment they buy is eco-friendly. In fact, the median amount they are willing to spend is around 65 SEK( swiss currency) extra. There is n increasing trend in demand of organically produced cotton garments which are expanding in global cotton market for niche product. * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address:[email protected]
2214-7853 © 2015 Published by Elsevier Ltd. Selection and peer-review under responsibility of the conference committee members of the 4th International conference on Materials Processing and Characterization. doi:10.1016/j.matpr.2015.07.020
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In this the world, though it the major employment generator, the textile industry is considered as ecologically one of the most polluting industries [2]. The issues which make the life cycles of textiles and clothing unsustainable are the use of harmful chemicals, high consumption of water and energy, generation of large quantities of solid and gaseous wastes, huge fuel consumption for transportation to remote places where textile units are located, and use of nonbiodegradable packaging materials. Chemical processing of textiles ranging from preparatory processing to dyeing and finishing majorly add its value for fashion and function. It is a matter concern that these processes use water, energy, and chemical intensive and cause serious environment hazard. Thus, global awareness on environmental demands natural fiber-based textiles , natural dye and finishes are gaining momentum in academic, research and industrial research. [3] The textile industry uses vegetable fibers such as cotton, animal fibers such as wool and silk, and a wide range of synthetic materials such as nylon, polyester, and acrylics. The production of natural fibers is approximately equal in amount to the production of synthetic fibers. Polyester accounts for about 50% of synthetic. The stages of textile production are fiber production, fiber processing and spinning, yarn preparation, fabric production, bleaching, dyeing and printing, and finishing. At the Each stage wastes generates, which is injected to the environment, because of that there is deterioration of environmental conditions. Depletion of the ozone layer, global warming, rapid disappearance of forest, pollution of water, noise and air etc. are the various problems arises due to the industrialization development. In the past few years, garment processing has become increasingly popular and exports of garments from India have been increasing with leaps and bounds every year. This has created a very healthy atmosphere for the growth of garment processing in our country. The majority of garments exported are cotton based. But the textile processors have come in for a lot of criticism over the last decade for its association with toxic chemicals and the occasional environmental horror story has stained its image. Processing is a term used to describe a wide range of preparation, coloration and finishing techniques performed on the garment. This is clearly identified as having a potentially adverse effect on the environment. Hence for today’s textile processor it has become absolutely necessary to take into consideration the ecological aspects in production of certain quality of garment. Alternatively garment dyers, printers and finishers are attempting to reduce the environmental impact of their processes and it is this area which is the subject of this article. 4 2. Eco-Friendly Processing: Definition With rapid industrialization and urbanization, coupled with the general tendency to assault nature by indiscriminate throwing of waste into the environment, there is a general deterioration of environmental conditions. Depletion of the ozone layer, global warming, rapid disappearance of forest, pollution of air and water, noise, dust, toxic gases, hazardous materials, etc. pose threat to the quality of life and all aspects of health and safety. Our natural resources have only limited ability to assimilate pollution due their restricted self-purification capacity. Hence a time has come to apply effective controls to regulate what and how much should be discharged, dumped or emitted in the environment.1 Garments are indeed our “second skin” and hence the customer is worried whether he is putting himself in contact with the “toxins in clothing”. Thus the need of eco-friendly processing of garment arises, generally referred as “eco-textile”.5 The word ‘eco’ is short for ecology. Ecology is the study of the interactions between organisms and their environment. Therefore ‘eco’ friendly (or ‘ecology friendly’) is a term to refer to goods and services considered to inflict minimal or no harm on the environment. There is really no such thing as a 100% eco friendly piece of clothing. This is because all clothing takes water (to grow the fiber which makes the fabric) and energy (to make the fabric and the garment).When we talk about eco friendly textiles, we are talking about those companies which make it a point to minimize this damage by using fibers not grown or produced with damaging chemicals, and fabrics not colored with harsh dyes and paints. In summary, ‘Eco’ friendly clothing might mean:-Clothing made of fibers such as organic cotton and hemp.-Clothing that has been organically dyed with vegetables.
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Eco-textiles are those that have been produced with the lowest possible negative impact on the environment. All aspects from origination right through to disposal have to be taken into account. The processor must be able to identify, understand and measure a lot of parameters and their relations. 6 Why eco? The main environmental issues associated with textile industry arise from emissions to water. The changing face of environmental legislation is causing serious problems for industries many and the textile industry is no exception. A new parameter that today increasingly vital is ecology. The logo of eco-labeling is becoming an increasingly important factor. Worldwide environmental problems associated with the textile industry are typically those associated with the water pollution caused by the discharge of untreated effluents and those because of use of toxic chemicals especially during processing. These chemicals can harm consumer if retained in the fabric. There is always a danger to the workforce in the industry via air, direct contact, accidental exposure etc. Hence the substitution of the non eco-friendly auxiliaries will only serve towards the consumer and the environment. The eco norms are also becoming stringent these days. Thus it is increasingly becoming necessary for the industry to adapt the novel trends which are benevolent to the nature. The Garment Industry And The Environment The garment industry occupies a unique place in our country. One of the earliest to come into existence in India,it accounts for 14% of the total Industrial production, contributes to nearly 30% of the total exports and is the second largest employment generator after agriculture. In the new competitive environment after the garment quota regime of quantitative import restrictions under the multi-fibre arrangement (MFA) have come to an end on 1st January, 2005, developing countries with both textile and clothing capacity may be able to prosper. Thus if the Indian garment industry has to compete successfully it has to immediately adopt positive measures to control all the stages of production to comply with the mandatory requirements of the foreign buyers. Garments are a result of a complex series of manufacturing processes, in the course o which an extremely diverse range of chemicals may be used. Some examples of these hazardous chemicals are 7:x Pesticides. x Pentachlorophenol. x Acidiy/Alkalinity (pH) x Dyestuffs. x Dye Carriers (Chloro organic). x Loose Dye. x Volatile Compounds. x Odours. x Formaldehyde. x Extractable Heavy Metals. x Flame Retardants. x Biocides. 2.1 Causes Of Pollution Due To Garment Processing 1.
2.
Use of chemical like potassium dichromate, sodium hydroxide or peroxide, sodium hypochlorite in the preparation process of desizing, scouring and bleaching with their associated wash-off stages produce heavy biological oxygen demands (BOD) in the effluent. Chlorine is prohibited for bleaching because of generating halogenated organic substance of which some are suspected to be carcinogenic e.g. chloroform. Dyeing and Printing: a. Use of azo dyes releasing harmful amines: - The amines, which are released from azo dyestuff in preference of a reductive chemical medium or by enzymatic action, exert their effect by causing DNA damage, which leads to tumor formation. The reduction
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products are electrophonic and covalently bonded to the nucleic acid of DNA resulting in DNA damage and hence inducing cancer. Use of dyes containing traces of heavy metals. Use of formaldehyde.
Use of formaldehyde as an easy care finish: Formaldehyde is a toxic chemical, skin irritant and sensitizer. Controversial animal inhalation tests with very high concentration have shown that it is a nasal carcinogen to rats and mice. b. Use of stiffeners containing plasticizer such as tributyl/triphynyl phosphate. c. Use of optical brighteners and softeners cause sensitizing effect. d. Application of flame retardant chemicals, manufacture and its transportation. Use of stain removers containing chlorinated products in garment manufacture. High energy and water consumption during processing. 8 a.
3 4
2.2 Various Terms Used In Eco-Friendly Processing The processor must be aware of certain terms and quantities used while determining the eco-friendliness of garment processing. Below are the three methods used to determine the amount of water pollution: I. Biological oxygen demand (BOD) BOD, mg/litre = (D1 – D2)/V Where D1 = Initial dissolved oxygen D2 = Dissolved oxygen after five days V = Volume of sample used II. Chemical oxygen demand (COD) COD, mg/litre = (B – A)*N*8000/V Where A= volume of ferrous ammonium sulphate solution used for titration in ml B= blank titration reading in ml N= normality of ferrous ammonium sulphate solution V= sample volume in ml 6 III. Adsorbable organic halogen (AOX) In this method, the organic substances are adsorbed from the sample onto (halogen free) activated charcoal. The charcoal is then burnt in a stream of oxygen and the hydrogen chloride formed is determined quantitatively. This parameter includes a wide range of compounds like volatile chlorinated hydrocarbons, plastic (PVC), toxic chlorophenols, etc.7 ECO-LABELS: Eco labels are fast assuming great significance for the successful export and market promotion in apparel textile industry. In addition to the requirement to the individual firms there are a large number of trademarks and labels for textiles, made available by associations, institutions and service companies of textile industry. Eco-labels are used as tools to identify green products. 11 Criteria for awarding of eco-label basically consist of: x General requirements of eco-toxicological and health aspects of chemicals used at various stages of processing x The demand that certain harmful substances are absent or present below the specified limits on marketed garment x Restrictions on the environmental impact of discharge in water/air during processing x Quality requirements as regard the fastness of the color and other performance Some of the popular eco-labels are The EU Eco-label, OKO-TEX Standard 100, Eco Mark, Green Seal, Blue Angel, etc.
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ISO 14000 The ISO 14000 series of International Standards have been designed to address those issues confronting environment today. The main goals of ISO 14000 are: a) Conservation of natural resources. b) Reduction and abatement of waste and emission. c) Continuous improvement in environmental performances. d) Efficiency in operation by use of best available technology. e) Compliance to National and International environmental laws and convention. 12 2.3. Strategies for eco-friendly processing: Any systematic approach to shift average production towards clean production should undergo the following steps: AVOID: To ‘avoid’ is to drop a procedure or product in favour of dramatically improving the environmental situation. REDUCE: This can be achieved by reduction of pollutant load, exhaustion and fixation of dyes close to 100 %( ideal) and saving of water and energy. REUSE: Reuse of the dyebath is an essential consideration under the pressure of dwindling resources. This has now become a reality due to inclusion of new auxiliaries, modern filter technology and spectrophotometers that measure the content of the dye in the dyebath accurately.
RECYCLE: The recycling of natural fibers is possible but is limited due their natural degradation. Synthetic fibers can be recycled by melting down and regranulating with or without the addition of fresh granules. This is probably the most acceptable to‘green’ organizations but is limited owing to lack of uses for the material recycled. 8 3. Garment Processing: Considerations The term ‘garment processing’ may be perceived as preparation, dyeing, printing and finishing operations performed on apparel that has been fully made and is ready for sale immediately after these operations. Now it would be interesting to ask why we bother to process garments at all? Pre-dyed yarn for knitwear and hosiery and pre-dyed fabric for woven goods would sometimes seem to be an easier option. However, there are several good reasons why garment processing is advantageous. ADVANTAGES: x Handling of smaller lots economically x Enables various special effects to achieved x Distressed look can be effectively imparted x Unsold light shades can be converted into medium and deep shades x By the time the garment has been in a boiling dyebath and then tumble dried, it will have adopted its lowest energy state and will not suffer further shrinkage under consumer washing conditions x Latest fashion trends can be effectively incorporated by immediate feedback from the customer But advantages are also associated with disadvantages, which are:
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x High cost of processing x A little complicated dyeing x Garment accessories like zips, buttons, etc impose restrictions. 13,14 GARMENT PROCESSING IS INVARIABLY A BATCHWISE PROCESS In garment processing the accessories play very important part that need to be considered: SUPPORT MATERIALS: These are important to provide shape, stability, increase retention of the original appearance and conceal garment interiors. These include linings, interlinings, shoulder pads, tapes, etc. Compatibility factors to be considered are they should have soft hand, flexibility, bulk and should be stable to heat and pressure. SEWING THREAD: Sewing is the most value adding stage in the entire garment manufacturing process. This is where the conversion of fabric cut pieces to garment takes place by means of stitches and seams. A stitch is the configuration of the interlacing of sewing thread in a specific repeated unit and seam is a line where two or more fabrics are joined. METAL COMPONENTS: Garment design incorporates certain metal components such as zips, buttons, etc. which can present difficulties to the garment dyeing operation 15,16. 4. Garment Processing Machinery Garment to be processed have to be carried out in specialized machines. Various types of machines have been developed to handle hundreds of individual articles of different shapes and sizes. The availability of equipment with high temperature capability further expands the potential of garment processing for both polyester and its blends. The machines likely to be used in garment processing are: 4.1 Hydro-Extracter Or Centrifuging Machine
Fig.1.Hydro - Extracter14,17 Hydro-extractors are ideal machines for extraction of water or liquid from garments. Machine has a central rotating (perforated) basket shell made of stainless steel or any other material lined rubber line FRP (Fiber reinforced plastic) covered with safety covers. The bottom part is of conical shape and is of heavy casting. Conical shape increases the centrifuging action and extracts the water from the garments. Machine is mounted on a triangular base and drive is given to basket by means of motor and V-belts. It rotates with a speed of around 650 – 1400 rpm. High-speed models are also available which gives much drier product in less time. Maximum permissible load varies from 70 – 400 kg. Thus water is removed from garments by exerting centrifugal force on garments. Centrifugal force will create tension in garments and thus RPM must be selected according to the strength of the fiber.
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Fig-2 Horizontal Paddle MachineFig. 3 Lateral Oval Paddle MachineFig.4 HT Paddle Machine
4.2 Paddle Dyeing Machine: These are very versatile and are generally of three types – I.Horizontal Paddle Machine This machine consists of curved back like lower section, which contains the material and the dye liquor. The goods are moved by a rotating paddle, which extends over the width of the machine. The paddle is just about half submerged in the liquor and moves the dye liquor evenly over the entire width of the back. The design of the paddle causes material to move upwards and downwards through the liquor. The material and the liquor move in an axial circular movement. II. Lateral Oval Paddle Machine Here the liquor flow is improved by constructing an oval tank. In the middle of this tank is a closed oval island around which the liquor is kept in motion. The paddle moves in lateral direction and is fully submerged in the liquor. III. HT Paddle Machine The operating principle is same as that of horizontal paddle machine. Here the liquor receptacle is cylindrical and is so designed that dyeing can be carried out at temperatures upto 140 0C.
Fig.5 Drum Dyeing Machine. Fig.6 Rotary drum dyeing machine
4.3 Drum dyeing cetrifuging machine: This machine is also called as “multipurpose drum machine” since it can perform all wet processing operations successfully with automated programme control. This machine is distinguished by the fact that it permits rapid loading and unloading, can operate with a very low liquor ratio and its ability for dyeing at temperatures upto 1400C 4.4Rotary Drum Dyeing Machine: Here a perforated drum is suspended along a lengthwise axis in the horizontal position submerged in the liquor. To ensure good movement of the material the drum is divided into four equal compartments separated by cross perforated dividing walls. The drum is capable of rotating in either direction. The compartments can be loaded individually.
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4.5 Tumble Driers:
After washing or dyeing garments are centrifuged and finally dried. This machine consists of perforated stainless steel drum, which rests on friction wheels. Loading and unloading can be done from front side or from the top of the machine. The suction unit draws the fresh air through the heating element and enters the drum, which is rotating. After drying the garments the air comes out of the machine through exhaust duct. Recently, tumblers are also available with reverse drive and also have automatic temperature control giving constant drying temperature. In modern machines temperature, moisture, air circulation rate, drum speed can be automatically adjusted. The garment processing route involves various stages which will now be discussed taking into consideration their eco-friendly aspect. 5. Garment Preparation One might ask why is it necessary to prepare garment or in that case textile substrate at all ? The answer is – x To remove natural substances such as oils, fats and waxes, pectin, etc. x To remove sizes and waxes applied during weaving x To remove soil accumulation x To achieve good and even absorbency for uniform dyeing x To remove self color of material 5.1 Desizing: Sizes constitute a basic problem for the ecology. In the manufacture of woven and knitted fabrics it is necessary to cover the yarn with a transitory finish, which is easily eliminated by water. This finish may amount to 20% of the weight of the fabric and has to be removed prior to further chemical processing. An analysis of dye house waste water shows the magnitude of this problem. Based on the measurement of the COD, it was demonstrated that 57%of the waste water load comes from sizes. Desizing is done to remove the various sizes applied to the fabric during sizing. Common sizes for cotton are starch, carboxyl methylcellulose, polyvinyl acetate, etc which are applied along with lubricants and waxes. Desizing is carried by two methods, the former being the popular one. I. BIOLOGICAL DESIZING This is carried using α-amylase enzyme. This is much safer than the oxidative desizing as the α-amylase enzyme attacks only the size and not the garment. Efficient desizing with α-amylase requires: 1. Thorough impregnation of fabric with enzyme solution 2. A digestion period for the conversion of starch into soluble dextrin 3. Proper temperature 4. Proper pH 5. Efficient washing/rinsing to remove the degraded starch II. OXIDATIVE DESIZING This typically employs an alkaline, oxidative solution of hydrogen peroxide or persulphate. Oxidative desizing is much more versatile than biological desizing as it removes a wide range of sizing agents. But these can damage the garment if not carefully controlled. ,18,19 5.1.1 ECO-FRIENDLY PROCESS In general about 50% of the water pollution load is due to the desized wash water which has a high BOD and COD. This can be minimized by: 1. Selection of sizes: The most commonly used sizing agent is starch whose decomposition products have a very high BOD and can no longer be reused. 2. Recovery and reuse of sizing polymer: In partial recycling, easily soluble sizes such as modified starch, polyvinyl alcohol, and polyacrylics are selected and the first, concentrated wash liquor, is isolated and
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only the other dilute washes are let off in waste water, thus reducing the pollution load by 50%. The isolated first wash water is reused by adding a calculated fresh quantity of sizing polymer. 20 5.2 Scouring: Scouring is typically performed in an alkaline solution and high temperature environment. The removal of natural impurities is based upon saponification at high pH. The removal of natural impurities can be done in a single process or can be combined with desizing and/or bleaching. The use of sequestering and reducing agents can be avoided when softened water is used. Impurities (natural as well as added) are totally removed in scouring process. This makes the fabric more absorptive without undergoing any chemical or physical change. 21 The main processes occurring during scouring are 1) Saponifiable oils are converted into soaps. 2) Proteins are hydrolysed into soluble degradation products. 3) Simpler ammonia compounds are hydrolyzed to ammonia. 4) Pectose and pectin are changed into soluble salts of pectic or metapectic acid. 5) Unsaponifiable waxes and oils are emulsified by the soluble soaps formed from saponifiable oils. 6) Dust particles are removed and held in stable suspension form in the kier liquor by the detergent present. 5.3 Bleaching: Bleaching is a process which removes the intrinsic color of the material, thus making it whiter in appearance. Oxidants typically used in bleaching are hydrogen peroxide and sodium hypochlorite. After scouring, cotton becomes more hydrophilic. However, the original colour stays unchanged due to coloured matter that cannot be completely removed by washing and alkaline extraction. When the material has to be dyed in dark colors it can be directly dyed without need of bleaching.18 Three chemicals are commonly used: 1) Hydrogen peroxide (H2O2) 2) Sodium hypochlorite (NaClO) 3) Sodium chlorite (NaClO2). The bleaching process is mainly divided into two categories. Such as: I. PEROXIDE BLEACHING II. HYPOCHLORITE BLEACHING 5.3.1 Eco-Friendly Process The scouring and bleaching processes have been identified as highly polluting and energy intensive. Scouring assistants containing chlorinated hydrocarbons, solvent emulsion are highly toxic. Hypochlorite bleaching is considered as main source of AOX and also results in formation of chloroform by reaction between chlorine and organic alcohols. Hence a greener process is badly required here which can be achieved using following methods: I. COMBINED SCOURING/BLEACHING: The bath is set with .5-1% alkali stable surfactant, 2-4% caustic soda flakes, 1-2% non-silicate stabilizer and 3-5% H2O2. MLR is kept at 1:10. Material is entered at room temperature and then the temperature is further raised to 85-900C. the material is treated for 40-60 min. Rinse the material thrice in water of gradually decreasing temperature. II. ENZYME APPLICATIONS: The discovery of novel, powerful alkaline pectinase promises to provide an eco-friendly, cost effective means to prepare cotton substrate. This unique pectinase functions well under slightly alkaline conditions in the presence of chelating and selected wetting agents. A combination of pectinase and cellulase significantly improves water wetting and retention properties, to level similar to those of commercially scoured cotton. Amongst other benefits listed are shorter washing process, savings in water consumption and increase in the efficiency and reproducibility of subsequent dyeings.19,22
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MERCERISATION Mercerization is the treatment of pure cotton fabrics or yarn with a strong caustic soda solution (usually 280-300 gpl) to improve strength, dye substantivity, strength and smoothness. The effects of mercerization 21 x
Improved luster , Increased ability to absorb dye,Improved reactions with a variety of chemicals ,Improved stability of form ,Improved strength/elongation & Improved smoothness etc.
Ways to minimise pollution in mercerising x Dilute alkali from mercerizing should be reused in scouring, bleaching or dyeing operations, so that discharges from alkaline treatment can be minimised, resulting less polluted effluents. x Liquid ammonia is a low pollution substitution for conventional mercerisation (NaOH). x
Heavy cotton fabrics treated with liquid ammonia require less dye for a given depth of shade, and consequently contribute to pollution abatement due to using less chemical for the same requirement.
Alkali should be recovered and recycled or reused after regenerative treatment to remove dirt (coagulation, flotation, microfiltration, nanofiltration) and after concentration. 6. Dyeing: The general dyeing technology for garments is the same as for standard exhaust procedures, except for pigment dyes. Here important factor to be considered are the accessories used in garment manufacturing. Adequate penetration of dye liquor into garment seams and a good balance between different fabrics and sewing threads used must be achieved. Garment dyeing is carried out as a batch process with a typical lot weight of 100 – 200 kg in the machineries discussed earlier. 18 6.1 Dyestuff Selection
While garments are made largely of 100% cotton, other fibers such as acrylic, nylon, wool and polyester/polyester blends can be processed. The table below illustrates dye classes available for different fibers. FIBER DYE CLASS Acrylic Cationic Cotton Direct Reactive Vat, Pigment Sulphur Nylon Acid Premetallized Polyester Disperse Wool Acid Premetallized Reactive The dyeclass selection will follow certain criteria: x What are the fastness requirements? x What are the cost requirements? x What is the shade range desired? What performance requirements will be needed because of the type of garments, machine restrictions, and dyeclass needed to meet fastness, cost, and shade demands? 23 6.1.1
Reactive Dyes Fiber reactive dyes are noted for their brightness and high wetfastness properties. Available in a complete range of shades. 6.1.2 Direct Dyes These are generally considered for their economy and short dyeing cycles but have limited wet fastness properties, particularly in heavy shades. 6.1.3 Vat Dyes For high fastness to industrial laundering, or where severe chlorinated water fastness is a requirement, there is a limited use of vat dyes. 6.1.4 Pigments
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Pigments produce bright, fluorescent shades of low wet-fastness properties at moderate cost. The theory behind exhaust dyeing of pigments is “cationization” of the garment. The garment is pretreated with a cationic dye acceptor forming a positive charge. Pigments being insoluble in water are made with additions of anionic surfactants and dispersants and therefore they have a negative charge. This results in deposition of pigments on the garment surface. These pigments are then fixed with a binder and further thermofixed during drying to improve the fastness. 24
6.1.5 Sulphur Dyes Sulphur dyes offer moderate to limited brightness of shade, moderate to low cost and generally lower wetfastness. Sulphurs would be an ideal choice for economic navies and blacks or when dyed garments are to acid washed. 6.1.6 Acrylic Dyeing Cationic dyes on acrylic will offer bright shades with excellent fastness properties. 6.1.7 Polyester Dyeing Disperse dyes for polyester offer wide range of shades, fastness properties, economics, and application flexibility. Polyester is far more difficult to dye than other synthetic fibers and requires either high dyeing temperatures or a carrier. 6.1.8 Nylon Dyeing For nylon, acid or premetallized acid dyes should be considered. Acids offer a complete range of bright shades with excellent leveling and moderate to good wet fastness properties. For improved wet fastness aftertreatment can be included. Premetallized dyes are less bright and have lower leveling properties than acids. However, premetallized dyes would offer improved wet fastness properties without requiring an aftertreatment. 6.1.9 Wool Dyeing Wool may be dyed with acid, premetallized or wool reactive dyes. Acid dyes would offer a complete, bright shade range with good leveling properties and moderate wet fastness properties. For bright, high wetfastness shades, the wool reactive dyes may be preferred.23 6.2 Eco-Friendly Process Of Dyeing Dyeing also commonly called as coloration is associated with significant environmental problems as: x In the manufacture of dyes due to use of carcinogenic intermediates x Discharge of dyes into streams. Azo dyes are readily cleared at the – N = N – bond to produce aromatic amines considered to be harmful. Auxiliaries used like carriers, dye fixing agents, retarders, heavy metal salts, etc. Hence to make dyeing more eco-friendly following strategies would be handy: Selection of dyestuff necessary from the following point of view – x Avoiding use of dyes which can form on reduction carcinogenic amines x Selection of high exhaustion dyes particularly among reactives x Avoiding the use of copper and zinc salts as aftertreatment agents or catalysts or reducing agents x Replacing the halogenated organic carriers with combinations of other carrier types Avoiding the use of chromium salts for the dyeing of acid dyes. 8 6.2.1 Cotton Dyeing x Optimization of fixation and washing off properties resulting in improved wash fastness thus cleaner effluent. High fixation means that very little unfixed dye must be washed off reducing the amount of waste water itself x Use of low salt range of reactives which need only fraction of the salt necessary for all other reactive ranges to ensure adequate exhaustion, fixation and reproducibility. Thus resulting in massive reduction of electrolytes in the waste water. 6.2.2 Polyester Dyeing x Improvement in the formulation of disperse dye to achieve increased dyebath and to decrease the need for carrier use x Producing readily-cleared alkali soluble disperse dyes, which eliminate the need for conventional reduction clearing x Use of low liquor ratios to reduce the effluent volume
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6.2.3 Wool Dyeing x Selection of wool reactive dyes which are metal free x Use of formic acid instead of acetic acid results in a substantial reduction in COD 6.2.4 Role Of Natural Dyes Although the use of natural dyes in the production of eco-textiles is attracting growing attention, their extraction and processing cannot, in general, be regarded as environmentally benign or even eco-friendly. For example, cochineal is extracted from lice by crushing them alive! Practical disadvantages also exist. To dye 1 kg cotton to a medium shade takes 20 g synthetic product such as reactive dye. To obtain the same shade with vegetable dyes requires approximately 1 kg dried leaves, equivalent to 5 – 10 kg freshly picked leaves. Thus even if only a small fraction of fiber to be processed are thus dyed, very large plantations are necessary. Also, mordants are often required to fix them.6 Thus the use of natural dyes only comes with a word of caution and hence the use of synthetic dyes is indispensable. 7. PRINTING Printing is used to show production of design of various colors and pattern on the fabric also called as localized dyeing. Here one or more colors are applied to the goods locally and then developed during steaming. Fabric printing is an age old art but garment printing is of recent origin say a maximum two decades. During the last one decade the technology has changed at a fast pace from its primitive hand operated printing machine to the latest fully automatic microprocessor controlled machine. So far only chest or the back or the sleeves of the garment could be printed but of late complete garment say a T-shirt can be printed with an over all print on both sides of the T-shirt. However sophisticated be the systems used to control the production, a printer will not succeed unless the design and colors appeal to the end user. There are two types of garment printing machines available viz. colossal (round) and oval type. The machines are available with a possibility of printing 4-12 colors and a print area of maximum 30” X 40” for overall prints. Both types of machines have pallets or boards of various sizes to suit the sizes and shapes of the garment. Pallets are necessary to avoid printing on the backside of the garments. A modern machine can print upto 600 garments per hour. The technology used on these machines is screen printing. Most popular colors used in garment printing are pigments, reactives and plastisols. In case of pigment printing it is necessary to use some kind of solvents viz. kerosene or mineral turpentine oil (MTO). 25 7.1 eco-friendly printing x Use of all aqueous system for pigment printing to avoid solvents, which are called as water base. The advantage being freedom from any toxic smell. x Use of automatic weighing systems which are capable of dispensing liquid dyes and even dye powders with minimal release of dust x Wastage of print paste can be reduced by installing return systems that recover much of the paste otherwise lost in supply pipes and from within the screens themselves x Residual paste can be recycled, with the assistance of colorimetric measuring and recipe prediction systems x The ultimate option is to recover the thickening agent from waste paste, this being achieved by the use of an ultrafiltration process; tests have shown that the recovered thickeners showed no degradation. x Continuous preparation of print paste to prevent the preparation of excess print paste. This entails an in-line measurement of the print paste consumption in the printing process. 26,27 8. FINISHING Finishing treatments are important to increase the appeal and usage characteristics of the garment. It assumes considerable significance because of the value addition realized through functional finishing of cotton in garment form to impart desirable properties. Some of the important finishes are discussed henceforth. 8.1 easy care / wrinkle free finishes One of the major shortcomings of cotton garment is its tendency to creasing during wearing and after washing. In order to impart wrinkle free appearance they are treated with cross linking agents. The process is traditionally known as resin finishing which imparts crease resistant property to cotton and keeps the shrinkage under control. The principle benefits in wrinkle free processing in garment form are: x Permanent fixing of creases at desired places
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x The risk of premature cross linking during drying, storage, and transportation is avoided x Puckering of garment seams is minimized There are two methods of garment finishing: 1. TUMBLE METHOD x 2. DIP METHOD 8.1.1 eco-friendly process Majority of cross-linking agents used today are formaldehyde based which are cost effective and efficient. However the release of formaldehyde vapors during processing as well as during storage and consumer use has caused worldwide concern of its impact on human health and environment due to its suspected carcinogenic and well-known dermatitis effects. Some of the approaches to limit problem of formaldehyde release are: x After wash of cured garment x Addition of formaldehyde acceptors or scavengers such as carbohydrazide, urea to the finishing bath x Application of 10-30% urea solution with 5-10% add-on by atomized spray technique using BASF fog chamber x Modification of DMDHEU with alcohol to produce etherified DMDHEU to decrease formaldehyde release x Treatment of DMDHEU with diethylene glycol or 2,3-propanediol. 29,30 8.2 softeners Garments are usually comfortable to wear if they are soft to touch. Chemical pretreatments remove natural cotton waxes rendering cotton harsh to handle. This is made worse after wrinkle free finishing. To compensate this; softeners are widely used. There are many kinds of softeners available which are classified as anionic, cationic, nonionic, amphoteric and reactive. Most famous being silicone softeners. Silicone is a general term that refers to class of man-made polymers based on the frame work of alternate silicone and oxygen bonds with organic substituents attached to silicones. Methyl group is the most important of organic substituents used in commercial silicones. 8.2.1 eco-friendliness Pdms becomes part of thewastewater stream in the form of tiny dispersed droplets and attach to suspended solids. Because non-volatile PDMS fluid is essentially insoluble in water, these materials become a minor component of the sludge. Though PDMS materials are highly resistant to biodegradation they break down into lower molecular weight products during soil contact. The degradation products are susceptible to biological decomposition eventually oxidizing to natural silica. 30 8.3 Bio Finishing For Denims Many garments especially jeans commonly referred as denim are defaced after machining to give it a faded look. The traditional methods involve pressure cooking of the jeans in presence of sodium hydroxide or an oxidizing agent. Moreover pumice stone has been used to achieve the same effects. Hence is also called as “stone wash” effect. This method has two main drawbacks: 1. It causes damage to the machine 2. Occurrence of pumice dust in the environment and in the garment creating a harsher handle. 8.3.1 Eco-Friendly Way: Enzyme technology now offers a novel process to achieve the same “stone wash” effect using cellulose enzyme which is generally referred as bio washing or bio finishing or in that case even as biostoning. Cellulases are multicomponent enzyme systems that are commonly produced by fungi and bacteria. Neutral cellulases are preferred for biostoning of indigo dyed denim trousers and other garments. Along with their eco-friendly advantage they also provide reduced pilling, durable soft handle and increased gloss or luster. 30,31 9. The Future of Garment Processing The current trend in clothing to the more casual and worn out look is proving to be very promising for garment processors. As has been shown, casual and distressed looks are better produced by garment processing and in some cases can only be achieved in this way. The chain stores are looking to shorter, more frequent seasons to stimulate sales. Already companies are changing colors and styles every few weeks, and the type of quick response is ideally suited to garment processing.
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Even the latest developments in electronics and information technology can be used to advantage for garment processing. It is now possible to develop color palettes using the Imagemaster system, which allows manufacturers to show ranges of new clothes on a screen without any physical garment manufacture or processing having taken place. Production can then commence, using garment processing wherever possible to replace stock quickly as it is sold.13,20 10. Consemer Acceptance While our industry is still far from perfect, and it will take a huge shift in consumer thinking to change wasteful consumption, this assignment gives us great hope that there are industry leaders out there pushing for a new industrial revolution. One that goes back to quality, not quantity, and encourages thoughtful manufacturing processes, as well as ecological awareness. There has been a significant increase over the past few years in the use of eco-labels, i.e. environmental labels attached to a variety of products to attract the attention of consumers about the environmentally positive features of the products. Generally these labels are voluntary and mostly used for the promotion of the products on the basis of their environmentally friendly characteristics. In the case of textiles and clothing there are for the time being no eco-labels the use of which has been enforced by mandatory rules. To enhance awareness about the environmental impacts of products, the Ministry of Environment and Forests (MoEF), Government of India (GoI) has initiated a sheme in 1991,which is basically a scheme of labeling the eco-friendly products .It is known as “Eco mark” scheme and aims at easy identification of eco-friendly products.The scheme is based on a “cradle to grave” approach and takes into account the impact of a product from the raw material extraction, to manufacturing, and to final disposal. an earthen pot has been chosen as a logo for the eco-mark scheme. There are different eco-labeling schemes both in developed and developing countries. The following list includes some of the government sponsored and some private labeling schemes: 32 Government Sponsered Scheams: x Angel (D), Eco Mark (JPN), x Environmental Choice (CND), x White Swan (Nordic Countries), x EU, Eco-Mark (India), x Green Label (Singapore) x Green Seal-(USA) x ToxProof-TUV (GERMANY) xFlower(EU) 11. Success of Eco-Friendly Processing For solving ecological problem a total commitment from top management to technologist and quality personnel is necessary. The chart shown below could be a guide to successful eco-friendly processing:7 Environmental policy x Commitment to continual improvement and prevention of pollution x Commitment to complying with relevant legislation and other requirements x Setting environmental objectives an targets
x x x x
Planning Environmental aspects Legal and other requirements Objectives and targets Environmental management programs
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x x x x x
x x x
Implementation and operation Structure and responsibility Training, awareness and competence Communication Operational control Emergency preparedness and response
Checking and corrective action Monitoring and measurement Nonconformance and preventive action Records
Management review Key to maintaining commitment throughout the organization
12. Conclusion The environment is nothing but conditions surrounding us. With respect to the human beings, it covers everything in the biosphere. Oceans, fresh water, atmosphere, rocks, soil, organism & so on. No doubt that the industrialization is must for the development & better standard of the living but it is detrimental to the overall quality of the life due to encroachment on the natural resources & injection of the pollutant in the environment. Along with the rapid increase in industrialization and the ever burgeoning population the production of textiles is bound to increase many folds. Thus, the already severe impact on the environment will get much more intense in the future. Also, as the public’s awareness and concern for the environment continues to increase, so the pressure on the garment processor for him to use eco-friendly processes will intensify. This needs a fundamental change in the attitude of the management and the technologists to take corrective actions for a brighter future of our garment industry and for exports in particular. References Levinson, Elsa, Thesis, Stockholm Universe, “Green clothes: A surveyof people’s willingness to pay for environmentally friendly clothes”, 2010. http://www.diva-portal.org/smash/record.jsf?pid=diva2:350380 2. A. K. Roy Choudhury ed. S.S.Muthu, Environmental Impacts of the Textile Industry and Its Assessment Through Life Cycle Assessment ; Roadmap to Sustainable Textiles and Clothing ,Textile Science and Clothing Technology Spinger,1-39, 2014 3. Kartick K. Samanta, S. Basak,S. K. Chattopadhyay, ed. S.S.Muthu, Roadmap to Sustainable Textiles and Clothing ,Textile Science and Clothing Technology, Spinger, 263-287, 2014 4. Mehta, K. H., A Journal of "Developments in environmental legislation in India with regard to dyes and chemicals industry." Colourage” 40, 49,1993 5. Prof.Dr.J.Mecheels , Melliand Textilber,74,(7), 159, 1994 6. G.Horstmann, Journal of Society of Dyers and Colorists ,Textile Technology Digest, publisher Institute of Textile Technology , 52, I7-12,1995 7. J.J.Shroff, Colourage, 47,17,2001 8. U.Sewekow, Textile Chemist and Colorist ,Publisher American Association of Textile Chemists and colorist, 28 (1) ,21-27,1996 9. J.Hilden, International Textile Bulletin, 40, (3),4, 1994 10. Prof.W.B.Achwal, A Indian Textile Journal,Colourage,, 99,1992 11. B.J.McCarthy and B.C.Burdett, Review of Progress in Coloration, 28 , 61,1998 12. M.Joshi ,Indian journal of “Fabre & Textile Research”, Environmental Management Systems For The Textile Industry ,28, 33-38, 2001 13. G.Cawood and J.Scotney, Review of Progress in Coloration, 30 , 35,2000 1.
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14. Mazadul Hasan ,Textile Engineer at INTRAMAX ,”Garment dyeing Machine”-slide Share, 2014 ,www.slideshare.net/sheshir/garments-dying-machine 15. “DOC” Cheek, American Dyestuff Reporter, 76, (8),74, 1987, 16. V.Budhiraja and Dr.Ela Dedhia, “Book of Papers” NCUTE, 113,2001 17. R.S.Bhagwat, Handbook of Textile Processing Machinery, Color publications, 1983 . 18. J.A.Bone, P.S.Collishaw and T.D.Kelly, Review of Progress in Coloration, 30,41, (2000) 19. J.N.Etters, B.D.Condon, P.A.Hussain and N.K.Lange, American Dyestuff Reporter,88, (6), , 19, 1999 20. Prof.W.B.Achwal, Colourage, 99, 1992 21. V.A.Shenai, “Technology of Bleaching and Mercerising”, Sevak Publication,3, 23,80,188,243,299, 2003 22. N.Duran and M.Duran, Review of Progress in Coloration, 30,41,2000 23. N.E.Houser, American Dyestuff Reporter, 80, (5), 18,1991, 24. D.C.Gore and J.H.Settle, American Dyestuff Reporter, 83,(5), 24, 1994, 25. D.K.Jain, Colourage, 43, (3), 23,1996 26. T.L.Dawson and C.J.Hawkyard, Review of Progress in Coloration, 30, 7, 1999 27. E.Roelofs and Tebodin.B.V, Melliand Textilber, 80,(6), 126, 2000 28. E.Menezes, Colourage, 48,(8) , 29, 2001 29. J.R.Provost, Journal of Society of Dyers and Colorists, 108 , 260, 1992 30. Dr.R.B.Chavan, “Book of Papers” NCUTE, 198,2001 31. D.L.Shah and Dr.A.Kulkarni, Man-made Textiles in India, 6, 1990 32. HJ Gam , A Journal of Fashion Marketing and Management , "Are fashionǦconscious consumers more likely to adopt ecoǦfriendly clothing ?", Department of Family and Consumer Sciences, : An International Journal, 15, (2), 178 – 193, 2011.
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