Pretreatment of textile substrates

Pretreatment of Textile Substrates......Page 1
Copyright......Page 3
Contents......Page 5
Preface......Page 11
1 - Pretreatment of cellulosics – singeing & desizing......Page 13
  1.1.1 Composition of cotton......Page 14
  1.1.2 Other impurities added to cotton during weaving or knitting......Page 18
  1.2.1 Plate singeing......Page 21
  1.2.2 Roller singeing......Page 22
  1.2.3 Gas singeing......Page 23
   1.2.3.2 Tangential singeing......Page 24
  1.2.6 Important care to be taken while singeing......Page 25
  1.2.8 Demineralisation......Page 27
  1.3.1 Effect of metal ions in preparation......Page 28
  1.3.4 Sizing requirements......Page 30
  1.3.5 Needs of subsequent processes......Page 31
  1.3.6 Starches......Page 32
  1.3.7 Modified starches......Page 34
  1.3.8 Cellulose derivatives......Page 35
  1.3.10 Polyvinyl alcohols......Page 36
  1.3.11 Polyacrylates......Page 37
  1.3.12 Polyester (PES)......Page 38
 1.4 Size possibilities in different fibres......Page 39
  1.5.1 Detection of size on the fabric surface......Page 40
  1.5.2 Size detections in the aqueous extract......Page 47
  1.5.4 Test and observations......Page 48
   1.5.4.2 Enzymatic starch decomposition......Page 49
   1.5.4.3 Preparation of chemicals for the above tests......Page 51
  1.6.1 Enzymatic desizing......Page 53
  1.6.2 Batch wise processes......Page 57
  1.6.3 Guideline recipes......Page 58
  1.6.4 Semi-continuous and continuous processes......Page 62
   1.6.5.1 Pad batch desizing......Page 63
  1.7.1 Water soluble starches......Page 66
   1.7.1.1 Acid treatment recipes......Page 67
   1.7.2.1 Pad-J box desizing......Page 68
 1.8 Oxidative desizing......Page 69
  1.8.1 Desizing with hydrogen peroxide (oxidative shock desizing)......Page 74
  1.8.2 Bromite desizing......Page 76
  1.8.3 Desizing of garments......Page 77
  1.8.4 Iodine test for starch–TEGEWA violet scale......Page 78
   1.8.4.2 Assessment......Page 79
   2.1.1.2 Obtaining a silky look......Page 82
   2.1.1.9 Improving % dye exhaustion......Page 83
   2.1.1.13 Improving moisture absorption......Page 84
  2.1.2 Mercerisation methods......Page 85
   2.1.2.1 Parameters of mercerisation......Page 87
  2.1.3 The practical mercerisation process......Page 89
  2.1.4 Changes in the properties of cellulose due tomercerisation......Page 96
  2.1.5 Mercerising machines......Page 97
  2.1.6 Hank mercerising......Page 101
  2.1.8 Single end mercerisation......Page 102
  2.1.10 Chainless/roller mercerising machine......Page 103
  2.1.11 Chain mercerizing machine......Page 105
  2.1.12 Merceriser with combined chainless–Chain combination......Page 108
  2.1.13 Batch mercerisers......Page 109
  2.1.14 Mercerising knitted fabrics......Page 110
  2.1.15 Stenter mercerising (SM) process......Page 114
  2.1.16 Caustic recovery......Page 116
   2.1.16.1 Other analysis method for mercerising process......Page 118
  2.1.17 Ammonia mercerisation......Page 121
   2.1.17.1 Process and theory......Page 122
  2.1.18 Prograde process–J. & P. Coats Ltd. (Scotland)......Page 123
  2.1.19 Sanforset process......Page 124
  2.1.20 Weight reduction (deweighting) of polyester......Page 125
   2.1.20.1 Discontinuous deweighting......Page 126
   2.1.20.2 Semi continuous and Continuous deweighting......Page 127
  2.1.21 Continuous reductive causticising process (CRC process)......Page 128
  2.1.22 One bath causticisation and bleaching (CBF process)......Page 131
 2.2 Scouring......Page 132
   2.2.1.1 Surfactants......Page 134
   2.2.1.2 Sequestering agents......Page 146
   2.2.1.4 Fibre protecting reducing agents......Page 149
   2.2.1.7 Emulsion scouring......Page 150
   2.2.1.8 Solvent scouring......Page 151
  2.3.1 Alkaline scouring......Page 152
   2.3.1.1 Kier boiling......Page 153
  2.3.2 Acid scouring......Page 154
  2.3.3 Continuous scouring......Page 158
  2.3.4 Preparation of cotton knitted goods......Page 163
 3.1 Bleaching of cellulosics......Page 169
  3.1.1 Hypochlorites......Page 170
  3.1.3 Sodium chlorite......Page 174
  3.1.4 Chlorite bleaching–Theory......Page 175
  3.1.5 Open-width bleaching using sodium chlorite......Page 179
 3.2 Hydrogen peroxide (H-O-O-H)......Page 184
  3.2.1 Mechanisms......Page 185
  3.2.2 Physical and chemical properties of hydrogen peroxide in various forms......Page 186
  3.2.3 Decomposition of hydrogen peroxide......Page 188
  3.2.4 Stabilisation of bleaches and bleach liquors......Page 189
   3.2.6.1 Sodium silicate......Page 190
   3.2.6.2 Polyphosphates......Page 193
   3.2.7.1 Some organic stabilisers (sequestrants) used in peroxide bleaching......Page 194
  3.2.8 Persulphates......Page 197
  3.2.9 Peracetic acid......Page 198
 3.3 Reductive bleach......Page 202
  3.4.3 Cold peroxide bleach–Pad roll–Cotton, Polyester/cotton wovens......Page 213
  3.4.4 Continuous desizing and cold pad batch bleaching (CPB)......Page 215
   3.4.5.1 Process technology: Wet-on-wet......Page 216
  3.4.6 Discontinuous methods......Page 219
  3.4.7 Bleaching knit goods on overflow machines (batchprocess)–Peroxide......Page 220
  3.4.8 Combined boil-off and bleaching......Page 221
  3.4.9 Continuous cold peroxide bleach......Page 223
   3.4.10.1 Continuous methods......Page 224
  3.4.11 Continuous hydrogen peroxide bleach......Page 225
  3.4.12 Bleaching of knitted goods......Page 231
  3.4.13 Continuous bleaching machineries for knitted goods......Page 234
  3.4.14 Bleaching with hypochlorites......Page 239
  3.4.15 Available chlorine and active chlorine......Page 243
   3.4.15.1 Formation of hypochlorite......Page 245
   3.4.15.3 Recipe for sodium hypochlorite bleach......Page 246
   3.4.15.4 Hypochlorite bleach–other materials......Page 248
   3.4.15.5 Classification of cellulose according to Cu fluidity values......Page 250
  3.4.16 The preparation of viscose and blends of viscose......Page 252
   3.4.16.1 Demineralising......Page 256
   3.4.16.2 Causticising......Page 262
   3.4.17.2 Desizing......Page 266
   3.4.17.4 Mercerisation......Page 267
  4.1.1 Features of linen......Page 270
   4.1.1.1 Cross-section of a flax stem......Page 271
  4.1.2 Enzymatic desizing/enzymatic scouring......Page 273
   4.1.2.1 Alkaline scouring......Page 274
   4.1.3.1 Continuous peroxide bleach (silicate)......Page 275
   4.1.3.3 Discontinuous peroxide bleach (silicate)......Page 276
   4.1.3.4 Pad-batch cold peroxide bleach......Page 277
   4.1.3.6 Chlorite bleach......Page 278
   4.1.4.2 Quality test for calcium on the fabric......Page 280
   4.1.4.3 Qualitative test for iron on the fabric......Page 281
   4.1.4.7 Sodium diethyldithiocarbamate test......Page 282
   4.1.4.8 Qualitative tests cellulosic damages......Page 283
   4.2.1.1 Wool......Page 284
   4.2.1.3 Scouring wool and woollen blends (WO, WO/PES, WO/PA)......Page 294
   4.2.1.4 Continuous scouring......Page 295
   4.2.1.6 Discontinuous bleaching......Page 296
   4.2.1.7 Discontinuous peroxide bleach for full bleach......Page 297
   4.2.1.8 Bleaching wool and its blends with synthetics......Page 298
 4.3 Silk......Page 299
  4.3.2 Chemical composition of mulberry silk......Page 300
   4.3.3.1 Cleaning and degumming......Page 301
   4.3.3.2 Degumming with soap solution......Page 302
   4.3.3.3 Degumming......Page 303
   4.3.3.4 Other degumming methods......Page 305
   4.3.4.1 Oxidative bleach......Page 310
   4.3.4.2 Reductive bleach......Page 311
  5.1.1 Pretreatment of Polyester......Page 316
   5.1.2.2 Washing of polyamide......Page 324
   5.1.2.3 Bleaching of polyamide......Page 325
   5.1.3.1 Desizing......Page 327
   5.1.4.2 Processing sequences for warp knitted fabrics......Page 329
   5.1.4.3 Pre-stabilisation......Page 330
   5.1.4.4 Heat setting......Page 332
  5.2.1 Pre-treatment of polyester/cotton (cellulosic) blends......Page 333
   5.2.1.2 Desizing......Page 334
   5.2.1.3 Heat setting......Page 336
   5.2.1.4 Scouring......Page 337
  5.2.2 Preparation polyester/acetate blends......Page 338
  5.2.4 Pre-treatment of polyester/acrylic blends......Page 339
   5.2.4.2 Full white......Page 341
   5.2.6.3 Heat setting......Page 342
  5.2.7 Pre-treatment of polyester/wool blends......Page 343
   5.2.7.2 Washing......Page 345
   5.2.7.3 Bleaching......Page 346
   5.2.7.4 Crabbing......Page 348
   5.2.7.5 Heat setting......Page 349
   5.2.8.1 Pre-treatment......Page 350
  5.2.9 Pre-treatment of acrylic/wool blends......Page 351
   5.2.9.2 Bleaching......Page 352
  5.2.10 Pre-treatment of acrylic/polyamide......Page 353
   5.2.10.2 Bleaching......Page 354
  5.2.11 Pre-treatment of acrylic/acetate blends......Page 355
   5.2.12.1 S-finish......Page 356
   5.2.12.2 Bleaching......Page 357
   5.2.13.1 Discontinuous scour boiling......Page 358
   5.2.13.2 Continuous scouring of Co, Co/PES, PA/Co, Modal/Co......Page 359
   5.2.13.3 Discontinuous scouring of synthetic fibres (PA, PAC, PES, CT, CA)......Page 360
   5.2.13.4 Continuous scouring of synthetic fibres (PA, PAC, PES, CT, CA)......Page 361
   5.2.13.5 Continuous scouring and washing of synthetic fibres......Page 362
   5.2.13.6 Discontinuous scouring and washing......Page 363
  5.2.14 Optical whitening......Page 364
   5.2.14.1 Optical brightening agents......Page 365
  5.2.15 Energy diagram of optical brighteners and transitions......Page 367
   5.2.15.1 Different groups of optical brightening agents......Page 368
   5.2.15.2 General molecular structure OBA......Page 369
   5.2.15.3 General requirements of an OBA for a textile processor......Page 370
   5.2.15.5 OBAs for cotton and viscose......Page 371
   5.2.15.6 OBAs for polyamide......Page 372
   5.2.15.8 OBAs for polyester......Page 373
   5.2.15.9 Typical recipes......Page 374
   5.2.16.1 Pad + heat-set......Page 376
   5.2.16.2 OBAs for wool......Page 377
  5.2.17 Preparation of elastane fabric......Page 378
   5.2.17.1 Storage of grey/partly processed fabrics......Page 380
   5.2.17.2 Relaxation......Page 381
   5.2.17.3 Heat setting......Page 385
   5.2.17.5 Heat setting of open -width material......Page 386
   5.2.17.6 Effect of heat setting temperature and time on the fabric......Page 388
   5.2.17.7 Heat setting efficiency......Page 389
  5.2.19 Scouring......Page 390
   5.2.20.1 Discontinuous one step peroxide bleach......Page 391
   5.2.20.2 Discontinuous reductive bleach for cotton elastane......Page 392
   5.2.20.4 Optical white for cotton/lycra and viscose/lycra......Page 393
  5.2.21 Combined scouring/bleaching of elastane fabrics......Page 394
  5.2.22 Modern continuous bleaching......Page 396
   5.2.22.1 Example recipes (Benninger CBR example)......Page 399
   5.2.22.2 Example recipes for preparation–Erbatech CBR......Page 403
   5.2.22.4 Example recipes......Page 406
   5.2.22.5 Recipes for Mezzera CBR......Page 408
 6.1 Bio-preparation......Page 410
  6.1.1 How an enzyme works......Page 413
  6.1.2 Mechanism of enzyme action......Page 416
  6.1.3 Enzyme activators and inhibitors......Page 417
 6.2 Cotton fibre morphology......Page 418
   6.2.1.1 Composition of the primary wall in cotton......Page 419
  6.2.2 Enzymes......Page 420
 6.3 Bio-preparation......Page 421
  6.3.1 Properties of enzymatic scoured fabrics......Page 422
   6.3.2.1 Bio-preparation process......Page 425
   6.3.2.2 All-in-one process......Page 426
  6.3.3 General yarn Bio-preparation procedure......Page 427
  6.3.5 Pad-roll Bio-preparation procedure......Page 428
   6.3.6.3 Enzyme-enhanced bleaching of wool......Page 431
   6.3.7.1 Degummase enzymes in the processing of silk......Page 432
  6.3.10 Other bio-treatments–Retting of flax......Page 434
   6.3.11.1 Bio-washing......Page 435
   6.3.11.2 Bio-polishing......Page 436
  6.3.12 Enzyme fading......Page 437
  6.3.13 Solvent scouring......Page 440
   6.3.13.1 Advantages and disadvantages of solvent scouring......Page 441
 6.4 Mineral earth–Technology for preparation ofcellulosics......Page 442
  6.4.1 Characteristics......Page 443
 6.5 Emerging technologies......Page 444
References......Page 450
Index......Page 455