Chemical Technology in the Pre-Treatment Processes of Textiles by S. R. Karmakar

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Chemical Technology in the Pre-Treatment Processes of Textiles
by S. R. Karmakar

Chemical technology in the pre-treatment processes of textiles

Contents

Preface
Chapter 1
Kinds of fibres
Introduction
Classification of fibres
Chemical composition, morphology and structure of cotton
1.3.1 Cotton impurities
Natural protein fibres
1.4.1 Molecular structure of wool fibres
1.4.2 Impurities in raw wool
1.4.3 Morphology and chemical structure of silk
Long vegetable fibres
1.5.1 Flax (linen)
1.5.2 Remie
1.5.3 Hemp
1.5.4 Jute
Regenerated natural fibres
1.6.1 Cuprammonium rayon
1.6.2 Viscose rayon
1.6.3 Acetate fibres
1.6.4 Regenerated protein fibres
Synthetic fibres
1.7.1 Polyester
1.7.2 Nylon
1.7.3 Acrylic fibres
1.7.4 Olefin fibres
Miscellaneous synthetic fibres
1.8.1 Chlorofibres
1.8.2 Poly(vinyl alcohol) fibres
1.8.3 Elastomeric fibres
1.8.4 Carbon fibres
1.8.5 PTO fibres (Enkatherm)
References
Other synthetic fibres 42
Chapter 2
Preparation before chemical processes
Introduction
Inspection
Sewing
Mechanical cleaning of fabrics
2.4.1 Brushing
2.4.2 Cropping and shearing
Singeing
2.5.1 Singeing different kinds of fibres fabrics
2.5.2 Plate singeing machine
2.5.3 Rotary cylinder machine
2.5.4 Gas singeing machine
2.5.5 Singeing circular knit fabrics
Process sequence
2.6.1 Cotton fabric on kier
2.6.2 Cotton fabric on J-Box
2.6.3 Cotton fabric on pad-roll/thermoreaction chamber
(T.R.C.)
2.6.4 Cotton fabric on Jumbo jigger
2.6.5 Knitted cotton goods
2.6.6 Woollen fabrics
2.6.7 Silk fabrics
2.6.8 Polyester fabrics
2.6.9 Nylon fabrics
2.6.10 Polyester/cotton blends
2.6.11 Polyester/viscose blends
2.6.12 Polyester/wool blends
2.6.13 Diacetate/viscose blends
Chapter 3 Desizing
3.1 Introduction
3.2 Methods of desizing
3.2.1 Rot steeping
3.2.2 Acid desizing
3.2.3 Enzymatic desizing
3.2.4 Desizing with oxidising agents
3.3 Desizing of synthetic fabrics and their blends
3.4 Desizing machineries
References
Chapter 4 Scouring
4.1 Introduction
4.2 Mechanism of removal of impurities
4.3 Scouting of cotton in alkaline agents
4.3.1 The lime-soda boil
4.3.2 The caustic soda boil
4.3.3 The soda-ash boil
4.3.4 The mixture of caustic soda and soda-ash boil
4.3.5 The soap/detergent-soda-ash boil
4.3.6 Sequestering agents
4.3.7 Builders
4.3.8 Fibre protecting reducing agents
4.3.9 Mild oxidising agents
4.3.10 Water insoluble solvents
4.4 Surfactants
4.4.1 Anionic surfactants
4.4.2 Cationic surfactants
4.4.3 Non-ionic surfactants
4.4.4 Amphoteric surfactants
4.4.5 Blends of surfactants
4.4.6 Surfactants as wetting agent
4.4.7 Surfactants as detergent (scouting agent)
4.4.8 Emulsion scouting
4.5 Solvent scouting
4.6 Scouting of raw wool
4.6.1 Emulsion scouting
4.6.2 Suint scouring
4.6.3 Solvent extraction scouring
4.6.4 Refrigeration process
4.7 Scouting wool yarn and fabric
4.7.1 Setting and scouting of wool yarn
4.7.2 Crabbing (setting) of woollen fabric
4.7.3 Potting of woollen fabric
4.7.4 Scouting of wool fabric
4.8 Carbonising of wool
4.9 Degumming of silk
4.9.1 Degumming in water
4.9.2 Degumming with alkali and acid
4.9.3 Degumming with soap
4.9.4 Degumming with synthetic detergents
4.9.5 Enzymatic degumming
4.9.6 Foam degumming
4.9.7 Partial degumming
4.9.8 Washing of degummed silk
Degumming of remie
Scouting of linen
Scouting of jute
Scouting of synthetic-polymer fibres
4.13.1 Polyester
4.13.2 Nylon
4.13.3 Polyacrylonitrile fibres
4.13.4 Acetate fibres
4.13.5 Regenerated cellulose
4.13.6 Texturised fabrics
Scouting of blended fibre fabrics
4.14.1 Polyster/cotton
4.14.2 Polyester/wool
4.14.3 Polyester/acrylic
4.14.4 Acrylic/wool
4.14.5 Acrylic/cellulosics
4.14.6 Acetate/wool
4.14.7 Blends containing viscose
4.14.8 Polyester/silk
4.14.9 Blends containing casein
References
Chapter 5
Scouring machineries
Introduction
Batch type (rope) scouting machines
5.2.1 Low pressure kier
5.2.2 High pressure kier
5.2.3 Jafferson-Walker’s kier
5.2.4 Gebauer kier
Batch type (open-width) scouting machines
5.3.1 Mather and Platt horizontal kier
5.3.2 Jackson kier
5.3.3 Jig process
Semi-continuous scouting machines
5.4.1 Padd-roll system
5.4.2 Padd-steam-roll system
5.4.3 Padd-roll on perforated cylinder
Continuous scouring machines
5.5.1 Saturator J-Box-rope washer
5.5.2 Open-width roller steamer
5.5.3 Batch or re-batching system
5.5.4 Vaporloc system
5.5.5 High pressure Klienewefer roller steamer
5.5.6 Conveyer storage steamer system
5.5.7 Roller-bed steamer with pre-swelling time
5.5.8 Continuous relaxing/scouring machines
5.5.9 Solvent scouting machines
Wool scouring machines
5.6.1 Raw wool scouting machines
5.6.2 Wool hank scouring machines
5.6.3 Wool fabric scouting machines
5.6.4 Carbonising range for woollen fabric
5.6.5 Crabbing and decatising machines
5.7 Silk degumming machines
5.7.1 Yarn degumming machines
5.7.2 Piece goods degumming machines
References
Chapter 6
Bleaching of textiles
Introduction
Bleaching with hypochlorites
6.2.1 Calcium hypochlorite (bleaching powder)
6.2.2 Sodium hypochlorite
6.2.3 Lithium hypochlorite and chlorinated trisodium phosphate
6.2.4 Factors effecting hypochlorite bleaching operations
6.2.5 Accelerated hypochlorite bleaching
6.2.6 Advantages of hypochlorite bleaching over bleaching powder 167
6.2.7 Disadvantages of sodium hypochlorite bleaching over bleaching powder 168
Bleaching with peroxides 168
6.3.1 Mechanism of peroxide bleaching 170
6.3.2 Stabilisers for peroxide bleaching 170
6.3.3 Parameters in peroxide bleaching operations 172
Bleaching of wool with hydrogen peroxide 173
6.4.1 In alkaline hydrogen peroxide 174
6.4.2 In acidic hydrogen peroxide 174
6.4.3 Alkaline peroxide followed by hydrosulphite treatment 175
6.4.4 Mordanting and peroxide bleaching 175
6.4.5 Sequential oxidative and reductive bleaching 176
6.4.6 In emulsion of hydrogen peroxide 178
Bleaching of silk with hydrogen peroxide 178
Bleaching of synthetic fibres with peroxide 180
6.6.1 Regenerated cellulose 180
6.6.2 Acetate fibres 180
6.6.3 Acrylic fibres 180
Advantages and disadvantages of peroxide over hypochlorite
bleaching 181
Bleaching with sodium chlorite 182
6.8.1 Mechanism of bleaching 182
6.8.2 Bleaching of cotton 183
6.8.3 Bleaching of polyester 184
6.8.4 Bleaching of nylon 184
Bleaching of acetate fibres
Bleaching of polyacrylonitrile
Bleaching of polyvinyl alcohol
Problem of corrosion and its prevention
Merits and demerits of chlorite bleaching
Bleaching with peracetic acid
6.9.1 Cotton
6.9.2 Nylon
6.9.3 Cellulose acetate
6.9.4 Acrylics
6.9.5 Merits and demerits
Reductive bleaching of wool
6.10.1 Sulphur dioxide
6.10.2 Sodium bisulphite
6.10.3 Sodium hydrosulphite
6.10.4 Thio-urea bleaching of wool
6.10.5 Photo-bleaching of wool
Bleaching of silk with reducing agents
Reductive bleaching of nylon
Peroxygen bleaching compounds
Bleaching of jute
6.14.1 Hypochlorite
6.14.2 Hydrogen peroxide
6.14.3 Sodium chlorite
6.14.4 Peracetic acid
6.14.5 Drawbacks in bleaching of jute
6.14.6 Causes of yellowing and improvement of photostability
of bleached jute
Bleaching of linen
Bleaching of blended fabrics
6.16.1 Polyester/cotton
6.16.2 Polyester/wool
6.16.3 Nylon/cellulose
6.16.4 Nylon/wool
6.16.5 Acrylic/cellulose
6.16.6 Acrylic/wool
6.16.7 Acetate/cellulose
6.16.8 Polyester/linen
6.16.9 Wool/viscose
6.16.10 Viscose/cotton
6.17 Bleaching of cotton weft knitted fabrics
References
Chapter 7
Bleaching and washing equipment
Introduction
Batch bleaching process machineries
Semi-continuous bleaching process machineries
Continuous bleaching by J-Box systems
Continuous open-width bleaching equipment
7.5.1 Steamers without plaited storage
7.5.2 Conveyer steamer without pre-steeping zone
7.5.3 Conveyer steamer with pre-steeping zone
7.5.4 Pressureless or Combi-steamers
7.5.5 Submerged bleaching systems
7.6 Washing equipment
7.6.1 Rope washing machines
7.6.2 Open-width washing machines
References
Chapter 8
Heat-setting
Introduction
Thermal behaviour of synthetic fibres
Stages of heat-setting
Methods of heat-setting
8.4.1 Contact method
8.4.2 Steam-setting method
8.4.3 Hydro-setting method
8.4.4 Heat-setting using tenter frame
8.4.5 Selective infra-red emitters method
Heat-setting conditions for different kinds of fibres
8.5.1 Polyester fabrics
8.5.2 Nylon fabrics
References
Texturised fabrics
Acrylic and modacrylic fabrics
Cationic dyeable polyester
Triacetate fibres
Polyvinyl chloride fibres
Elastomeric fibres
Heat-setting of blended fibre fabrics
8.6.1 Polyester/cotton
8.6.2 Polyester/wool
8.6.3 Polyester/linen
8.6.4 Polyester/silk
8.6.5 Polyvinyl chloride/cellulosics
Effect of heat-setting on properties of synthetic fibres
8.7.1 Structural changes
Dimensional stability
Stiffness
Crease recovery
Dyeability
Chapter 9
Mercerization
Introduction
Conditions for mercerization
Changes in properties of cellulose on mercerization
9.3.1 Swelling and shrinkage
9.3.2 Structural modification
9.3.3 Increased lustre
9.3.4 Gain in strength
9.3.5 Increased moisture absorption
9.3.6 Increased dye absorption
9.3.7 Increased reactivity
9.3.8 Removal of immature cotton
9.3.9 Physical compactness
Mercerization of remie and flax fibres
Mercerization of blended fibre fabrics
Mercerizing machineries
9.6.1 Cloth (woven) mercerizing machines
9.6.2 Yarn mercerizing machines
9.6.3 Knit goods mercerizing machines
9.7 Hot mercerization
9.8 Liquid ammonia mercerization
References
Chapter 10
Optical brightening agents
Introduction
Chemical constitution of optical brighteners
Mechanism of fluorescent whitening
Factors influencing the functions of optical whiteners
10.4.1 Substrate
10.4.2 Saturation
10.4.3 Method of application
10.4.4 Time
10.4.5 Temperature
10.4.6 pH
10.4.7 Salt
10.5 Application of optical brighteners
10.5.1 Cellulose fabrics
10.5.2 Woollen fabrics
10.5.3 Silk fabrics
10.5.4 Polyester
10.5.5 Nylon
10.5.6 Polyacrylonitrile
10.5.7 Cationic dyeable polyester
10.5.8 Polyvinyl chloride
10.5.9 Other synthetic polymers and plastics
10.5.10 Blended fibre fabrics
References
Chapter 11
Combined pre-treatment processes of textiles
Introduction
Combined scouring and desizing
Combined scouring and bleaching
11.4 Combined desizing, scouting and bleaching
References
Chapter 12 Degradation of fibres associated with chemical pre-treatment processes
12.1 Introduction
12.2 Degradation of cotton during desizing
12.3 Degradation of cotton during scouring
12.4 Degradation of cotton during bleaching
12.4.1 Hypochlorite bleaching and damage
12.4.2 Peroxide bleaching and damage
12.5 Damage of wool during pre-treatment processes
12.6 Damage of silk during pre-treatment processes
12.7 Damage of polyester during pre-treatment processes
References
Chapter 13 
Conservation of energy and water, economy and effluent control in pre-treatment processes
Water consumption in textile industry
Impurities in water
Water purification
13.3.1 Soda-alum process
13.3.2 Lime-sodaprocess
13.3.3 Base exchange process
Economy through energy conservation
13.4.1 Efficient generation of energy and minimum consumption
13.4.2 Mechanical removal of water before drying
13.4.3 Increased efficiency of drying and heat-setting
13.4.4 Reduced liquor to material ratio
13.4.5 Efficient heat recovery
13.4.6 Heat recovery from process effluents
Economy through water conservation
13.5.1 Minimising liquor to material ratio
13.5.2 Minimising wash liquor
13.5.3 Re-using rinsing bath water
13.5.4 Direct steam injection
13.6 Economy through process modification
13.6.1 Vaporloc bleaching
13.6.2 J-Box bleaching
13.6.3 Solvent scouting
13.6.4 Cold bleaching
13.6.5 Combined processing
13.6.6 Shortening of process sequence
13.7 Pollution aspects in pre-treatment processes of textiles
13.7.1 Water and air pollution
13.7.2 Parameters for assessment of harmful materials in waste water
13.8 Pollution load and pre-treatment processes
13.8.1 Desizing effluents
13.8.2 Scouting effluents
13.8.3 Bleaching effluents
13.8.4 Auxiliary effluents
13.9 Waste water treatment from pre-treatment plants
13.10 Protective measures for ultra-violet radiation
References
Chapter 14
Pre-treatment of textiles under plasma conditions
Introduction
The concept of plasma
14.2.1 Corona discharge
14.2.2 Glow-discharge
14.3 Generation of plasma and its action
14.3.1 Machine performance for producing plasma
14.3.2 The interaction of plasma with substrate
14.4 Surface modification of fabrics under plasma treatment
14.4.1 Plasma treatment of wool
14.4.2 Plasma treatment of other fabrics
14.5 High energy radiation of textiles
References
Chapter 15 Application of bio-technology in the pre-treatment processes of textiles
15.1 Introduction
15.2 Enzymes for textile application
15.2.1 The chemistry of enzymes
15.2.2 Mechanism of enzyme action on cotton
15.2.3 Parameters governing the cellulase treatments
15.2.4 Structural and morphological changes of fibres by enzymatic hydrolysis
15.2.5 The use and advantages of enzymatic processing
15.3 Treatment of cotton with enzymes
15.3.1 Enzymatic desizing of cotton and silk
15.3.2 Use of enzymes in mercerization
15.3.3 Enzymatic scouting and bleaching processes
15.3.4 Bio-polishing
15.3.5 Effect of cellulase treatment in washing processes
15.3.6 Stone washing
15.4 Treatment of protein fibres with enzyme
15.4.1 Wool carbonising
15.4.2 Wool bleaching
15.4.3 Shrink-proofing and modification of wool
15.5 Bio-technology and effluent treatment
References
Chapter 16
Analysis and testing in preparatory processes
Introduction
Analysis of water
16.2.1 Suspended matter
16.2.2 Total soluble salts
16.2.3 Total hardness
16.2.4 Calcium hardness
16.2.5 Magnesium hardness
16.2.6 Temporary and permanent hardness
Analysis of non-cellulosic residues
16.3.1 Ash content (mineral matter)
16.3.2 Silicate and phosphate
16.3.3 Calcium and magnesium
16.3.4 Iron and copper
Evaluation of wax content in cotton
Evaluation of lubricants
16.5.1 Total fatty matter
16.5.2 Saponification value of an oil
16.5.3 Unsaponification matter
Determination of moisture content
Tests and analyses of sizes
16.7.1 Identification of sizes
16.7.2 Percentage size by ordinary method
16.7.3 Total size by Soxhlet method
16.7.4 Total size by enzyme method
Determination of the efficiency of scouting
16.8.1 Measurement of weight loss
16.8.2 Measurement of residual wax content
16.8.3 Practical test of absorbancy
16.8.4 Removal of motes (kitties)
Testing and evaluation of bleaching agents
16.9.1 Bleaching powder
16.9.2 Sodium hypochlorite
16.9.3 Sodium chlorite
16.9.4 Hydrogen peroxide
16.9.5 Stabilisers for peroxide bleach
16.9.6 Sodium hydrosulphite
16.9.7 Sodium bisulphite
16.9.8 Sodium silicate
Assessment of damage of cellulose
16.10.1 Determination of fluidity
16.10.2 Determination of Copper Number
16.10.3 Methylene Blue absorption test
16.10.4 Silver nitrate test
16.10.5 Determination of acidic groups by iodometric method
Assessment of damage of wool
16.11.1 Microscopic test
16.11.2 Swelling test
16.11.3 Solubility test
16.11.4 Spectrophotometric test
16.12 Determination of degree of mercerization
16.12.1 Deconvolution count
16.12.2 Swelling index
16.12.3 Benzopurpurine test
16.12.4 Sodium hydroxide spotting test
16.12.5 Goldthwait red-green test
16.12.6 Staining test
16.12.7 Barium activity number
16.12.8 Determination of lustre
16.12.9 X-ray analysis
16.12.10 Infra-red analysis
16.13 Evaluation of whitening efficiency of optical brighteners
16.13.1 Visual assessment
16.13.2 Extraction method
16.13.3 Instrumental analysis
16.14 Determination of degree of heat-setting
16.14.1 Shrinkage test
16.14.2 Crease recovery angle
16.14.3 Assessment of handle
16.14.4 Iodine absorption method
16.15 Determination of biodegradability of surfactants
16.15.1 Methylene Blue method
References
Subject index 474

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