1. ECO-FRIENDLY TECHNOLOGIES FOR TEXTILE PRODUCTION.
R.B.Chavan
Former Professor,
Textile Dept. IIT Delhi
Consultant, MGIRI, Wardha
E-mail rbchavan@hotmail.com
Abstract
Cradle to grave or womb to tomb is the most effective concept for cleaner production activities
including textiles. This concept has coined the terms such as production ecology, user ecology
and disposal ecology. According to this concept it is no longer adequate to have a finished
product to be safe only to human beings but the production processes and the product disposal
after use should be environment friendly. In the present paper attempt has been made to discuss
critically the cleaner production technologies such as use of organic cotton, naturally coloured
cotton, environment friendly Reactive, Vat, and Sulphur dyeing and finishing processes for
cotton, the use of synthetic thickener as a substitute for kerosene in pigment printing. Eco-norms
Eco-labels for identification of environment friendly textiles and the attempts made by the
Government of India, Ministry of Textiles to facilitate the use of eco-friendly textile production
are briefly discussed.

2. Introduction
During the manufacture of textiles very large number of chemicals are used e.g. during
the cultivation of cotton, the use of fertilizers, pesticides is quite common, during sizing one uses
size preservatives and during chemical processing a large number of chemicals, textile
auxiliaries, dyes, pigments, thickeners, finishing agents etc are used. Many of these agents are
responsible for problems during their handling, water and air pollution causing health problems
to human beings, aquatic life, plant and foliage. Thus giving rise to various environmental issues.
In India no serious thought was given to these environmental issues caused by industrial activities
in general and textile production in particular till recently Germany has put the ban on the use of
certain azo dyes, commonly known as German Ban.
Eco-friendly Textiles
The German Ban acted as catalyst to develop the concept of eco-friendly textiles. In
developing this concept "Cradle to Grave" or "Womb to Tomb" approach is followed. According
to this concept textile industry should take the environmental and health hazard aspects into
consideration right from the stage of fibre cultivation/manufacture to spinning, weaving,
chemical processing, apparel manufacture, packaging and disposal after use. The material flow
diagram during textile production is shown in Fig. 1

3. Fig. 1 MATERIAL FLOW ALONG THE TEXTILE
CLOTHING CHAIN
Synthetic Natural
Production
Fibre Fibre
Basic chemicals - Cultivation
Fibre,
petrochemistry .fertilizers
yarn,
Production of pesticides
fabric
monomers / - Crop
auxiliary
Textile Processing
e.g. desizing,
mercerizing, bleaching,
dyeing, printing,
finishing
Garment / Textile industry
Use
Packing, washing, dry-cleaning
Disposal

4. In order to make the textiles totally environment friendly, not only the final product to be
used by the consumer be eco-friendly, but the production technology, packaging and disposal
after use should also be eco-friendly. Therefore, the production ecology, user ecology and
disposal ecology must be taken into consideration.
Production Ecology
This comprises of
• Cultivation and harvesting of natural fibres
• The manufacture of regenerated and synthetic fibres
• Yarn and fabric manufacture
• Textile chemical processing
• Garment manufacture
• Packing
The production should be as environmentally sound as possible with regard to its impact on
air, water, soil as well as human beings.
User Ecology
This refers to the aesthetics, performance characteristics and effects of textiles on human
body.
Disposal Ecology
This refers to the disposal of textiles after use i.e. to recycling, composting, dumping,
incineration in a manner that ensures that the least possible environmental impact.
Eco-fibres
Organic Cotton
Cotton is cultivated using pesticides, fertilizers and other crop related chemicals. The
residues of these chemicals remain on cotton bolls. These residues are removed during the
preparatory processes and enter into the wash liquor resulting in water pollution. Therefore, in
true sense, cotton cultivated by using such chemicals is not considered to be eco-friendly. A trend
is started to cultivate cotton without the pesticides, fertilizers and other chemicals. Such cotton is
considered to be eco-friendly and is known as natural cotton, green cotton or organic cotton.
The use of biotechnology to introduce disease resistant cotton and organic farming
techniques may decrease the use of chemicals, pesticides, herbicides, fungicides, defoliants and
harvest aid chemicals used for cotton cultivation. This would help to decrease soil pollution

5. during cultivation and water pollution during preparatory processes. The eco labels shown in fig.
2 identify the organic cotton
Fig 2 Eco-labels for cotton
Naturally coloured cotton
Naturally coloured cotton of various colours particularly green and brown varieties were
cultivated since ancient times in many countries. However, such cotton did not gain commercial
popularity due to low yield, short staple length, poor fibre strength, poor spinnability and possible
contamination due to pollination. The present environment protection trends have given impetus
to the revival of cultivation of naturally coloured cotton. Such cotton is not subjected to dyeing
and thus is free from pollution caused by dyeing operations.
Lyocell
It is regenerated cellulose marketed by Courtalds. It is obtained by wet spinning of cellulose pulp
dissolved in an aqueous solution of an eco-friendly solvent N-methyl morpholine oxide
(NMMO). The solvent can be totally recovered, purified and recycled.
Biodegradable Polyester (Corn Fibre)
Kanebo spinning and Kanebo Gohsen of Japan, jointly developed an environment friendly
corn fibre under the trade name Lactron. It is produced from lactic acid obtained through the
fermentation of corn starch. Strength, stretchability and other properties of Lactron fibre are
comparable to petrochemical based nylon and polyester except lower melting point (175o C). The
fibre is suitable for both textile and non-textile applications.
Environment Friendly Chemical Processing
The input/output analysis during chemical processing of textiles is shown in Fig 3

6. Fig. 3 Input / output analysis of Textile chemical Processes
Base chemicals
(e.g. acid, Alkali, Textile Energy
sodium chloride) Natural Fibres; 10-20 MJ/kg
Dyes
Chemical Fibres: 5-50 MJ/kg
Water
Textile Auxiliaries
60-360 l/kg textile
Wet Processing
(pre-treatment,
dyeing, printing,
finishing.)
Polluted Air Waste
Sewage sludge:
60-70 g/kg textile
Water Effluent
Large number of base chemicals, dyes, auxiliaries, and finishing agents are used during
chemical processing of textiles as in put. As an out put we have air pollution, water pollution and
problems of sludge disposal. There are two major pollution control strategies
• Cleaner production techniques and processes
• End-of-pipe treatments
Cleaner Production Techniques and Processes
Some of the cleaner production techniques with reference to cotton are discussed.

7. Dyeing
Different dye classes which are suitable for dyeing of cotton and the chemicals in the
effluent stream is shown in Table 1
Table 1 - Chemicals in effluent streams
Dye Chemicals in effluent streams
Vat Residual dyestuff (5 - 20 %)
Reducing agents
Oxidising agents
Detergents
Salt
Reactive Residual dyestuff (20 - 50 %)
Salt
Alkali
Detergent
Direct Residual dyestuff (5 - 20 %)
Salt
Dye fixing agents
Sulphur Residual dyestuff (30 - 40 %)
Sodium sulphide
Alkali
Salt
Dyeing of Cotton with Reactive dyes
Amongst the different dye classes suitable for dyeing of cotton, reactive dye class is the
most important.

8. The use of reactive dyes is predicted to rise by 50%. Presently, most of the reactive dye
manufacturers are concentrating on addressing the following environmental problems associated
with the reactive dyes:
Colour in the effluent.
Minimization of chemical usage.
Colour in the Effluent
Removal of colour from the effluent is one of the expensive approaches for the end of
pipe technology. Therefore, it is necessary to find suitable alternatives. In exhaust dyeing, the use
of reactive dyes is the major source of concern. The vat, sulphur and azoic dyes exhibit a high
degree of exhaustion and the insoluble unfixed dye can readily be removed as a part of the
primary flocculation process. Whereas in case of reactive dyes, sometimes as high as 30% dye
remains unbound during primary treatment and needs to be treated either on site as a secondary
process after biological oxidation or at a municipal sewage works. The adsorption of hydrolyzed
reactive dye on biomass is not as efficient as of other water-soluble dye classes. However, the
amount of hydrolyzed dye in the effluent can be minimized through process innovations.
The government pressure for regulating industrial effluent discharge has led to the
development of new reactive dyes, machinery and processes to minimize waste and colour in the
effluent. The development of bifunctional reactive dyes is important from this point of view.
Bifuntional Reactive Dyes
Bifunctional reactive dyes consist of two reactive groups capable of forming covalent
bonds with the fibre. There are two types: (i) those consisting of two similar reactive groups
(homobifunctional reactive dyes) and (ii) those with two different reactive groups
(heterobifunctional reactive dyes). Fig. shows various homobifunctional. and heterobifunctional
reactive dyes presently marketed by main dyestuff manufacturers .
Fig. 4 Homo and Hetero Bifuntional Reactive dye

9. The characteristics of these dyes is their high exhaustion and high reactivity with the fibre
so that there is less quantity of dye in the effluent.
Dye Liquor Wastage
Minimization of dye liquor wastage is a major environmental consideration in a
continuous dyeing to reduce colour in the effluent. At the end of every dyeing, there is liquor left
in the pad trough as well as in the stock tank prepared as a precaution against running out before
the dyeing is completed. A latest development from Monforts (Matex 3 bowl padder) has the
feasibility to decrease the pad liquor volume to 15 litres as the fabric comes to the end of the run.
Ramisch Kleinwefers has also developed a padder with a minimum trough volume of 10 litres.
2.2 Minimization of Chemical Usage
Some of the approaches to minimize the use of chemicals are:

10. Dyeing at low liquor ratio.
Right-first-time approach.
Process innovations in continuous dyeing.
Use of low-salt reactive dyes.
Dyeing at Low Liquor Ratio
The average consumption of water per kilogram of finished fabric is around 80-100 litres.
Lowering of liquor ratio bring down the volume of water used and the waste generated. Apart
from the easier handling of lower volume of effluent, the dosing of chemicals and auxiliaries in
the dye bath is done on the basis of g/litre of liquor. This significantly reduces the quantities of
chemicals and auxiliaries and finally the effluent load. In reactive and vat dyeing systems, a
change of liquor ratio from 1:10 to 1:5 brings about a decrease in pollution load by about 40%.
Right-first-time Approach
Carefully following the dyestuff manufacturer’s recommendations for salt, alkali usage,
temperature, time, etc. to ensure optimum fixation levels and right-first-time production, thereby
avoiding the need to make shading additions. The computer colour matching should help in this
regard.
Low salt Reactive Dyes
Substantial quantities of electrolytes, such as sodium chloride and sodium sulphate, are used
for the dyeing of cotton with reactive dyes. Exhaust dyeing with 10:1 liquor-to-material ratio
needs a salt concentration of 30-80 g/L. This corresponds to 300-800g salt per kg of dyed cotton.
During effluent treatment, only a small quantity of salt is removed. Thus, a major quantity of salt
enters the environment on discharge of effluent treated water. High salt concentration in effluent
has the following disadvantages :
Rivers and lakes get polluted with effluent containing high salt concentration .
Fresh water organisms can have toxic effects.
In the regions with scarce fresh water resources, such water has to be used for irrigation. If salt
concentration is too high, soil may become overloaded with salt, and making the land infertile
and ultimately useless.
Low salt reactive dyes
Ciba Speciality Chemicals has introduced low-salt Cibacron LS dyes, which require only 20
g/L salt, whereas the conventional reactive dyes require 60-80 g/L salt for exhaustion. The dyes
have the general structure as shown in Fig. . The main features of these dyes are given below:
• Bifunctional reactive dyes have medium reactivity, but high dye affinity and high dye
fixation.
• Stable dye-fibre bond
• Less dye to be removed from fabric after dyeing.
• Rinsing step is much faster.
• Less water is needed for wash off.
• Less dye effluent.

11. Fig. 5 General characteristics of Cibacron LS dyes
Chromophore bridge Chromophore
Reactive Reactive
group group
As the salt requirement is reduced to ¼ of that required for conventional dyes, the saving in
cost is observed. Another benefit is that rinsing step after dye application is much faster and less
water consuming. Since the Cibacron LS dyes have a higher fixation rate than the conventional
dyes, this leads to lower dyestuff concentration in the effluent.
Ecological benefits of Cibacron LS dyes are summerized in Fig 6.
Fig. 6 Higher fixation rate of Cibacron LS dyes
Conventional dyes Cibacron LS (bireactive)
60 % fixation 80 % fixation
600 gm on the fibre + 33% 800 gm on the fibre
%
1 kg dye 1 kg dye
400 gm into 200 gm into
the waste water - 50% the waste water
%
Alternative Reducing Systems for the Dyeing of Cotton with Vat and Sulphur Dyes
Vat Dyes
Vat dyes are applied by using sodium hydrosulphite as reducing agent and sodium hydroxide as
an alkali. A few of the byproducts formed are sulphur compounds like Na2S which pollute air
through the formation of H2S. At the same time, the salts of sulphur in the form of sulphate and
sulphites (Na2SO3, NaHSO4, Na2SO4, Na2S2O3) contaminate sewage, lower its pH and show
corrosive action on concrete pipes. To overcome these problems, attempts were made by several

12. researchers to develop alternate reducing systems, which are ecofriendly in nature. Such new
systems include electrochemical reduction, use of organic reducing agents like hydroxy acetone,
iron pentacarbonyl compounds and iron (II) complexes.
Sulphur Dyes
Sodium sulphide is commonly used for the reduction in the application of sulphur dyes on
cotton. Residual sodium sulphide acts as contaminant in the effluent. Sodium sulphide causes no
marked odour nuisance above pH 9 but in acidic pH, gaseous H2S is liberated, giving fowl smell
of rotten eggs and is toxic when inhaled. Its odour threshold value is 10 ppm
Replacement of Sodium Sulphide
Glucose
Glucose has long been known as reducing agent for sulphur dyes. Sulphur black is almost
always reduced using glucose A considerable improvement is achieved when the dyeing is
carried out under strongly alkaline condition
Chavan and Vhanbatte obtained glucose by acid hydrolysis of molasses and cane sugar.
On the basis of detailed investigations of various parameters, such as concentration of glucose,
caustic soda, temperature and time, they concluded that at dyeing temperature of 90oC, glucose
gives colour yield equivalent to that obtained with sodium sulphide. Century mill at Mumbai also
established, on commercial scale, that sodium sulphide can be totally replaced with glucose
obtained from hydrolysis of starch.
Synthetic Thickener for Pigment Printing
Emulsion thickener using kerosene oil or mineral turpentine oil was the ideal and most
popular thickener for pigment printing of cotton. However, emulsion thickener poses serious
health hazards, fire hazards and air pollution problems. Attempts to recover and recycle kerosene
or MTO were not successful. Synthetic thickeners based on polyacrylates have successfully
replaced emulsion thickener in pigment printing. Many indigenous as well as imported products
are readily available.
Easy care or Wrinkle free Finishes
Majority of cross-linking agents used today are formaldehyde based including DMDHEU
and etherified DMDHEU, which have low formaldehyde level. Formaldehyde based cross-
linking agents are cost effective and efficient. However, the release of formaldehyde vapours
during finishing processes as well as during subsequent storage and consumer use of finished
products has caused world wide concern on its impact on human health and environment because
of the fears that it is carcinogenic and its well known dermatitis effects. The release of
formaldehyde is restricted to 20-ppm level. Non-formaldehyde based cross linking agents is one
of the approaches which has been explored.
Polycarboxylic acids (PCA) as cross linking agents
An alternative approach has been based on the use of PCAs. In 1998 Welch reported that
cotton fabric treated with 1,2,3,4 butane tetra carboxylic acid (BTCA) in presence of sodium
hypophosphite showed high level of wrinkle resistance and strength retention as well as good
durability to home launderings. However, exceedingly high cost has prevented the use of BTCA

13. on commercial scale. Citric acid (CA), a low priced tri-functional carboxylic acid is less effective
to home launderings than BTCA. It also causes yellowing of fabric under curing conditions.
Other carboxylic acids
Performance of various PCAs has been compared with conventional methylol derivatives as
wrinkle free finishing agents using sodium hypophosphite as catalyst. Most of these acids
imparted DP rating of 4.3-4.7, and crease recovery angle 285-300°. However, the resultant
finishes differed considerably in durability in alkaline laundering. The acids arranged in order of
decreasing durability in terms of maximum number of washings and tumble drying cycles
withstood were as follows
BTCA>CA>Maleic acid.>Succinic acid.
Softeners
Fabrics and 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 usually made
worst after wrinkle free finishing. To compensate this; softeners are widely used. They also act
as fibre lubricants decreasing both fibre-fibre and fibre-metal friction. The draping and, cutting
properties are also enhanced. The trend is towards the use of silicone softener that provides a soft
luxurious handle, thereby imparting a higher quality and added value to the material.
Silicone softeners
Silicones have been used as textile softeners since 1960.
Currently available silicone softeners can be classified as
1. Non-reactive
2. Reactive
Studies indicate that the silicone softeners are safe to environment as well as human health.
Bio finishing
Cellulase enzymes are widely used for the bio-polishing of cotton and for producing stone wash
effects on indigo dyed denim. The technology is well established and widely accepted as eco-
friendly.
Identification of Eco-friendly Textiles
Eco Parameters and Norms for Eco-friendly Textiles
In the past textiles were considered primarily from economical, functional and fashion
points of view. More recently consumers are imposing demands on the safety of textiles for the
health and also on the environmental soundness as decided by eco-parameters stipulated by well
established organizations. These norms are based on the analysis of textile products entire life
cycle commencing from cultivation of raw material (e.g. cotton), various production stages,
packing, distribution, utilization and disposal after use. For formulating eco norms different
classes of chemicals are considered. These are

14. Toxic Substance Process
Pesticides Cotton cultivation
Penta chlorophenol Sizing
Emulsifiers, chlorinated solvents Scouring
Halogeneted carriers Polyester dyeing
Sodium hypochlorite bleaching
Azo dyes containing banned amines Dyeing, printing
Dyes containing traces of heavy metals Dyeing, printing
Formldehyde as dye fixing agent Dyeing, printing
Formaldehyde cross-linking agent Finishing
Chlorinated stain removers Garment manufacture
Insecticides Packaging wooden boxes
Some of the most important eco-parameters are given in Table
Table 2 Comparison of norms/criteria stipulated for eco-lebelling of textiles
Eco-parameter M.S.T OTN 100 Clean Steilmann Comitextil Indian
Fashion ec0-lable
Formaldehyde
Baby clothing 20 20 20 50 20 20
Close to skin 75 75 75 300 75 75
Outer Wear 300 300 300 300 300 300
Toxic 1 5 1 1 0.1-1 1
pesticides
Pentachloro 0.5 - 0.5 Ban 0.05-0.5 0.5
phenol
Heavy metals
Arsenic 0.1-0.2 0.1-0.2 0.1-0.2 0.1-0.2 0.1-0.2
Lead 0.04-0.8 0.04-0.8 0.04-0.8 0.04-0.8 0.04-0.8
Cadmium 0.005-0.1 0.005-0.1 0.005-0.1 0.005-0.1 0.005-0.1
Mercury 0.001-0.1 0.001-0.1 0.001-0.1 0.001-0.1 0.001-0.1
Copper 3-100 3-100 3-100 3-100 3-100
Cobalt 0.2-20 0.2-20 0.2-20 0.2-20 0.2-20
Zinc 5-100 5-100 5-100 5-100 5-100
Nickel 0.2-10 0.2-10 0.2-10 0.2-10 0.2-10
Azo dyes Ban Ban Ban Ban Ban 50
containing
carcinogenic
amine
Halogen Ban - - Ban Ban 200
carriers
Chlorine - - - To avoid Ban -
bleaching

15. Eco Trade marks, Eco Labels
There are large number of eco trade marks, eco labels are available for identification of
eco-friendly textiles. These eco labels are made available by associations, institutions and service
companies of the textile industry. Most of these initiatives were originated in Gemany, but they
claim validity for the whole Europe and in some cases for the whole world. Ministry of
Environment and Forest under the certifying agency of Bureau of Indian Standards (BIS) has also
developed eco label. Some of these eco labels are given in Fig.
Fig. 7 Eco labels
Republic of China–Taiwan European Union Eco-label “Flower”
Green Mark
India Eco Mark Netherland Ecolabel Foundation
Commercial Activities
Organic cotton is grown at several places in India. Naturally coloured cotton comes in
fawn brown and pista green colour. It was grown in India in olden days. Textile items made from
organic and coloured cotton fetch considerable higher price. Green minded people are willing to
pay high price for eco-friendly textiles, which are free from carcinogenic dyes and harmful
chemicals.
Eco-friendly apparels
Eco friendly apparels are manufactured by the following industries in India
1. Alps Textiles, ghaziabad: Produce vegetable dyes and fabrics dyed with vegetable dyes.
2. Reymonds : Green shops in most big cities. Products are free from banned dyes.
3. Arvind Mills : Eco-friendly denim using pesticide free cotton. Trade mark-Ecologically
optimized fabric (EOF) issued by Eco-Tex, Germany. Specialized environmental stores in
Switzerland like Globus and Jumoli are marketing arvind Mills EOF denim. Arvind mills
also have plans to introduce EOF denim in US and European markets.

16. 4. Coats Viyella : Astra brand sewing threads, free from carcinogenic dyes
5. Century Mills : Cool cotton and Eco-friendly fabrics and garments. Also developed eco-
friendly process for dyeing of cotton with Sulphur dyes.
Efforts Made by Government of India
To meet the challenges posed by eco regulations by Germany and other countries, the
Government of India, through the Ministry of Textiles and the Ministry of Environment and
Forests, charted two approaches, viz. regulatory and developmental. Some of the regulatory
measures and development efforts include the following:
Regulatory Measures
• Prohibition on the use of 112 dyes, which are capable of releasing harmful amines.
• Evolution of eco standards and logo for eco-friendly textiles.
Developmental Efforts
• Organization of educative seminars, workshops and camps to inculcate the eco-friendly
concepts among the industry and consumer.
• Assistance to be provided by Textile Research Associations and Textile Committee to textile
units for securing ISO 9000 Quality System Certification and ISO 14000 Environment
Management System Certification.
• Keeping in mind the need for modernization on war footing, the Ministry of Textiles has
announced the scheme called Technology upgradation fund (TUF), wherein the credit is
available at concessional rate of interest to enable industry to take up modernization projects
in a big way.
• Similarly, as part to support textile industry for testing of eco-friendly textiles, the Ministry of
Textiles took up a massive programme of setting up of eco testing laboratories. In this
pursuit, the Textile Committee, a statutory body under Ministry of Textiles, is identified as a
nodal agency.
Conclusion
Two approaches viz. clean production technology and end of pipe treatment are available
to deal with the environment problems. Among these, clean production technology is more
effective. Some of the clean production technologies for dyeing, printing and finishing of cotton
are highlighted. Eco- friendly textiles are identified by means of eco labels which are based on
eco norms. Government of India Ministry of textiles made serious efforts to popularize the
concept of eco-friendly textiles and provided facilities in terms of setting up of eco laboratories
and modernization funds to textile industry.