problems and remedies in wet processing of cotton 100% - P.Shroff

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This presentation is based on problems & remedies in wet processing of cotton. starting from grey room to finishing.

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problems and remedies in wet processing of cotton 100% - P.Shroff

  1. 1. Problems & Remedies in Wet Processing of 100% Cotton (Woven) - Pathik Shroff
  2. 2. PROCESS SEQUENCE Grey Room Shearing Cropping Singeing Desizing Scouring Bleaching Mercerization Dyeing Printing Finishing
  3. 3. GREY ROOM Sr .no. defects causes Remedies 01 Thick & thin place . 1.Immature fibre . 2.Staple length. 3.Neps. 4.Drafting limitation 1.Selection of raw material. 1a.Mature fibre. 2.Good staple length. 3.Maximum Neps should be removed (carding & combing). 4.set Required draft.(no of doubling , speed of drafting roller.) 03 Weft bar Count variation Density of pick more.  use Less variation of weft count. Required density of weft. 04 End & Pick missing •Warp stop motion not working on loom at warp break. •Moving empty shuttle •Breakage of weft thread •Use warp stop motion as per break . •New extra thread joining •Mending.
  4. 4. Weft bar Missing Ends & Pick
  5. 5. SHEARING & CROPPING Sr .no. defects causes Remedies 01 Cut or holes damage to fabrics. 1.Presence of metallic particle on fabric. 2.Due to abrading action. 1.Use magnetic metal detector in feeding device. 1a.Removal of metal particle from grey fabric. 2.Covering the emery roll with a piece of cloth which reduce abrading action. 02 Rough & uneven surface of fabric. Inefficient Sharpness of blade. Grinding to blade & proper position & adjustment of blade
  6. 6. HOLES, CUT
  7. 7. SINGEING Sr .no. Defects Causes Remedies 1 Incomplete singeing 1. low flame height 2. fast fabric speed 3. High Moisture content 1. flame height 4”- 6” 2. Fabric speed 90-120 m/min 3. Ensure moisture content should be 6-8% 2 Uneven singeing [lengthways] 1. Change in fabric speed during Singeing 1. Maintain Uniform fabric speed through out Singeing 3. Thermal damage or Reduction in tear strength 1. Too slow fabric speed 2. close distance between the fabric and the burner 1. Fabric speed must be set Above 60-70 m/min 2. From 6-8 mm upto 6-20 mm distance between the fabric and the burner
  8. 8. FABRIC BEFORE SINGEING & AFTER SINGEING
  9. 9. DESIZING Sr. No. Defects Causes Remedies 1. Incomplet e desizing 1. Inappropriate desizing bath pH Set pH of bath depend on enzyme type of enzyme pH 1. Malt extract 6-7.5 2. Pancreatic 6.5-7.5 3. Bacterial 5.5-7.5 2. Inappropriate desizing bath temperature Temperature of bath must be 80-95◦ C . 3. Insufficient fabric pick- up 3. Use of wetting Agent 4. Deactivation of enzyme due to presence of metals or other contaminants 4a. Use of soft water 4b. Use of appropriate sequestering agents
  10. 10. Sr. No. Defects Causes Remedies 2 Uneven Desizing 1. Foaming in the bath 1. Use of appropriate defoamers 2. Inappropriate bath temperature 2. Ensure bath temperature of bath 80-90◦ C 3. Non-uniform washing after desgizin 3. Ensure Hot wash at 95◦C for 10-15min Thorough and uniform washing after desizing 4.Preferential drying of outer layers of the batch 4a. Covering the batch with polythene or other suitable sheet 4b. Keep the batch rolling 5.Temperature variation during digestion 5. Covering the batch with polythene or other suitable sheet
  11. 11. SCOURING Sr. No. Defects Causes Remedies 1. Inadequate absorbency or High residual impurities Inadequate concentration of scouring chemicals Check recipe Sodium carbonate - 2-3% owf Anionic detergent - 1-3 g/l Incompatible or ineffective surfactant/wetting agent Compatible and effective surfactant/wetting agent Water hardness or ineffective chelating agents Use of soft water or effective chelating agents 2 Tendering or damage or loss in strength 1. Presence of air in the machine, leading to the formation of oxycellulose 2. Contamination of iron 1a. Exclusion of air 1b. Use of mild reducing agent 2a. Water purification 2b. Use of appropriate complexing agent
  12. 12. BLEACHING Sr. No. Defects Causes Remedies 1. Uneven whiteness 1. Use of inappropriate surfactants 2. Water hardness 3. Irregular chemical feeding 4. Condensation or water marks 5. Foaming in the bath 6. Inappropriate use of defoamer 1. Appropriate/ compatible surfactants 2. Soft water or use of sequestering agents 3. Optimum chemical feeding 4. Optimum steaming conditions 5. Appropriate use of defoamer 6. Appropriate use of defoamer 2 Resist marks 1. Deposits of insoluble salts of surfactants 2. Redeposition of impurities 1. Use of soft water or appropriate chelating agents 2a. Careful selection of scouring auxiliaries 2b. Thorough washing after scouring
  13. 13. BLEACHING Sr. No. Defects Causes Remedies 3. Harsh handle 1. Silicate deposits 1a. Use of organic stabilisers 1b. Optimum control of pH (low pH reduces silicate solubility) 1c. Thorough washing after bleaching 4. Fibre degradation OR Reduction in fibre strength 1. Metal contaminants 1a. Treatment of water to remove metal contaminants 1b. Use of appropriate complexing agents
  14. 14. Sr. No. Defects Causes Remedies 5. Low degree of whiteness (Bleaching fabric by pad-Steam) 1.Residual sodium acetate after Neutralization 2.Too low bleaching pH 3.. short steaming time 4. low steaming temperature 1.Thorough rinsing after Neutralization 2. Ph 10-11 3. Steaming 60-90min 4. Steaming at 90-95◦ C Check no leakage of steam
  15. 15. MERCERIZATION Sr. No. Defects Causes Remedies 1. Low increase in lustre 1.Low concentration of Caustic 2. Insufficient fabric stretching while on the frame 3. Dwell time 1.Caustic concentration must be 52◦ Tw or 26 Be 2. Use of tensioner device 3. dwell time should be 60 sec 2. Poor shrinkage control 1. Insufficient fabric stretching while on the frame 2. Too much caustic on the fabric as it comes off the frame 1. Optimum fabric stretching while on the frame 2. Removal of excess caustic from the fabric before it comes off the frame
  16. 16. DYEING Sr. No. Defects Causes Remedies 1. 1. Poor Washing Fastness in Direct Dyeing 1. Dye substantivity, too high 2. Inherent low fastness properties of the dyes 1a. Treatment with Copper salts Copper sulphate 0.5-2% owf, Acetic acid 0.5% temp- 80◦C time 30-45min 1b. Treatment with chromium compound Potassium dichromate 2-3% owf Acetic acid 1-2% owf Temp- boil , time -30 min 2. Use of cationic dye fixing agents or other fastness improving aftertreatment
  17. 17. PROBLEMS IN REACTIVE Sr .no. defects causes Remedies 1.Shade change/ inconsistent shade Shade change/ inconsistent shade 1. Residual peroxide, alkalinity or other contaminants in the substrate 2. Water hardness 3. Contamination of dyebath with calcium, magnesium, chlorine or heavy metals 4. Improper use of dyebath assistants, e.g. surfactants, sequestrants, fixatives, lubricating agents 1. Substrate free from contamination before dyeing 2. Use of soft water or appropriate sequestrants 3. Use of appropriate sequestrants 4. Use of compatible dyebath assistants 2. Poor colour yield Poor colour yield 1. Poor pre-treatment 2. Residual peroxide in the substrate 3. Dye hydrolysis (only in case of reactive dyes) 1. Good pre-treatment 2. No residual peroxide in the substrate 3a. Careful storage of dyes 3b. Use of freshly prepared dye solution
  18. 18. PROBLEM IN VAT DYEING defects causes Remedies Poor levelling/uneven dyeing 1. Low dye diffusion 2. High dye affinity 3. Dyes of poor migration 4. Over reduction of the dye .5 Low liquor flow rate 6. Poor rinsing before oxidation 7. Uneven washing/soaping after-treatments. 1. Use of dyes of good diffusion 2. Use of dyes of optimum affinity 3. Use of dyes of good migration 4. Use of sodium nitrite to avoid over reduction of the dye 5. Optimum liquor flow rate 6. Thorough rinsing before oxidation 7. Thorough and uniform washing/soaping after treatments. Premature oxidation 1. Presence of air inside the Machine. 2. Insufficient amount of sodium dithionite and/or alkali 1. Prevention of air inside the Machine. 2. Optimum amount of sodium dithionite and/or alkali
  19. 19. cause reason remedie Oxidation patch in vat dyeing Improper oxidation - Sodium bicarbonate rinsing after after dyeing & prior to oxidation Poor rubbing fastness 1. Dyes of poor rubbing fastness 2. Catalytic damage of the material 3. Presence of polyvalent ions 4. Too high moisture in the test material 5. Improper use of finishing agent 1. Use dyes of good rubbing fastness 2. No catalytic damage of the material 3. Use of appropriate complexing agents 4. Proper conditioning of the test material 5. Proper use of finishing agents
  20. 20. Problem Cause remedie Shade change/ inconsistent shade 1. Residual peroxide, alkalinity or other contaminants in the substrate 2. Water hardness 3. Contamination of dyebath with calcium, magnesium, chlorine or heavy metals 4. Improper use of dyebath assistants, e.g. surfactants,sequestrants, fixatives, lubricating agents 1. Substrate free from contamination before dyeing 2. Use of soft water or appropriate sequestrants 3. Use of appropriate sequestrants 4. Use of compatible dyebath assistants
  21. 21. Other Dyeing Problem Problem Cause remedie Specky dyeing. Too much foaming during padding. water drop on fabric before or after padding. Add defoamer if required depending on class of dyestuff. take preventive measures. maintain the temp. speed & time . Patchy dyeing. Insufficient dip in padding trough Selection of proper padding mangle. Centre to selvedge variation. Uneven wearing out of rolls of padding mangle. Temp.gradient from centre to side of steaming chamber Check the uniform expression of padding mangle. Ensure uniform temp.across width of steamer. Tailing effect. Too large size of padding trough. Use narrow & deep trough of smaller capacity.
  22. 22. Patchy Dyeing Shade Variation Shade Bar
  23. 23. Problem in Jigger Dyeing defects causes Remedies Dark or light selvedge . Non-uniform batching on jigger . Proper batching on jigger. Streakiness. Improper function of tensioning device in jigger lead to too high tension to wet state. Ensure proper functioning of tension rollers on jigger. Face to face variation. Too high batching tension on jigger. Ensure correct batching on jigger.
  24. 24. Problems in Jet & Winch Dyeing Sr .no. defects causes Remedies 01 Crow –feet mark (crush mark). Improper jet diameter . Use suitable jet depending on fabric quality. 02 Oil stains . Use wrong type defoamer which are break in rapid jet dyeing cause staining problem. Use self emulsifying type silicone defoamer.
  25. 25. Crush marks Oil Stains
  26. 26. Problems in Continuous Dyeing defects Causes Remedies Specky dyeing. Too much foaming during padding. water drop on fabric before or after padding. Add defoamer if required depending on class of dyestuff. take preventive measures. maintain the temp. speed & time . Choke feeding lines. Inferior dye dispersion Improper selection of dyestuff. Centre to selvedge variation. Uneven wearing out of rolls of padding mangle. Check the uniform expression of padding mangle. Tailing effect. Too large size of padding trough. Use narrow & deep trough of smaller capacity.  Use hydraulic controlled rollers Colour dosing system PLC Dye stuff stain  Due to improper handeling  improper mixing of dyes •Ensure proper housekeeping Proper mixing of dyes
  27. 27. Dye Stain White Spots
  28. 28. PRINTING
  29. 29. Defect cause by Hanging Thread Problem Cause remedies A break in Pattern of Printed fabric caused by Hanging Thread Loose thread not treammed well before Printing Non mendable
  30. 30. MISPRINT Problem Main Cause Remedies: MISPRINT -Design not set properly -unequal pressure -Screen Design not Properly Engraved -cloth feed with uneven tension -Check Proper Feeding of cloth & Speed of m/c -Ensure proper engraving of Design
  31. 31. TINTING Problem Cause Remedies Tinting -Uneven Printing roller & doctor blade pressure -Printing Paste level not maintained -- defective doctor blade - Printing table not proper -Check viscosity of Printing Paste -Check doctor blade -Check Screen
  32. 32. BLURERD PATCH - Problem Cause Remedies Blurred patch Uncleaned Doctor blade & printing roller -Doctor blade not properly aligned cleaned Doctor blade & printing roller -Doctor blade properly aligned
  33. 33. WATER MARK Problem Cause remedies Water maks -Contamination with water prior to tinting on padding mangle -Surface pressure of one layer over another -Ensure proper cleaning of padding mangle -- ensure optimum pressure
  34. 34. MISFITS Problem cause Remedies Misfits -Printing screen Not adjusted properly -Improper feed of fabric -Faulty engraving -Proper adjustment of screen -- ensure proper feed of fabric use guiders, feed rollers -Ensure proper Engraving acc. To pattern
  35. 35. FLUSHING Problem Cause remedies Flushing -Printed area bleed into unprinted Portion -Removal of unfixed print Do curing at reqired temperature
  36. 36. SPOTTING Problem Cause remedies Spotting -Unclean Screen roller -Spots due to handling -Poor uptake of print paste -Cleaning of screen -Avoid marks in steaming -- ensure proper squeegee pressure
  37. 37. PRINT COLOUR VARIATION Problem Cause Remedies Colour variation -Uneven squeegee pressure - Check even appliation of pressure through out application of print paste.
  38. 38. BLEEDING Problem Cause Remedies Bleeding -Too low viscosity of color paste -Too high dyestuff concentration Ensure proper viscosity of Print paste - Ensure optimum concentration of dyestuff taken
  39. 39. STAINING DURING STEAMING Problem Main cause Remedy: Staining during steaming -Poorly washed printing Table -Irregular Steam & temperature Ensure Optimum Temperature while Steaming for reactive 102-105ºC
  40. 40. SLIGHT TOUCHING Problem Main Cause Remedies SLIGHT TOUCHING -Uneven Squeegee Pressure -A squeegee with improper Hardness -Improper viscosity of paste -Improper use of thickener -Optimum squeegee pressure -- check squeegee before use -Ensure viscosity of paste -Proper use of thickner
  41. 41. DOUBLE PRINTING Problem Main Cause Remedy Double printing -Disfigured design -Poor engraving -Poor cloth adhesion Ensure Proper engraving
  42. 42. PRESSING PASTE BY FRAME Problem Cause Remedies Pressing paste -Poor belt drive and frame installation -Frame mark in printed area -Proper frame installation over fabric
  43. 43. FINISHING
  44. 44. STARTING MARKS Problem Cause Remedies Staring marks 1. Sudden start, stopped of machine 2. Squeezing roll not properly clean 3. At start fabric pass throgh finishing chemical & not squeeze properly 1. Avoid sudden start and stoppage 2.Squeezig roller clean 3. Ensure proper squeezing action
  45. 45. BOWING Problem Cause Remedies Bowing 1. Uneven tension during processin g 2. Guiders not present 1. Maintain even tension Use of Weft straightn er 2. Use of guiders
  46. 46. PILLING Problem Cause Remedies Pilling 1. Broken filament 2. Low twist 1. Shearing , singeing 2. Ensure optimum twit
  47. 47. PIN HOLES Problem Cause Remedies Pin holes 1. Stenter pin 1. Go for clip for holding fabric
  48. 48. Finishing (Stenter) Sr .no. defects Causes Remedies 01 Clips cuts and escape . Inadequate grey width or reed space Mechanical defect in clip bar & chain rails of the stenter. Use provide adequate grey width & reed space with shrinkage expected. Ensure proper maintenance of clips & chain rails of stenter. 02 Yellow stains . Overheating & curing of the finished especially when acid liberating are used in finish . Optimum drying & curing condtion w.r.t time ,temp. 03 Oil dropping & carbon soot . Condensation of duct & water , oil particles Ensure proper cleaning of stenter exhaust. 04 Uneven heat setting. Variation in parameter Maintain parameter.
  49. 49. Calendering (Finishing) Sr .no. defects causes Remedies 01 creases & cut . non-alignment of guide rolls on calendering m/c giving rise to crease formation. Improper stitching of cloth. Proper selvedge to selvedge stitching of material & proper feeding over well aligned guide rolls . 02 Dent mark & stains .  Dents in the calendering bow Filling of dent.& proper brushing of the bowl .
  50. 50. Sanforiser(Finishing) Sr .no. defects causes Remedies 01 Rubber blanket marks . Dent or uneven surface of the rubber blanket . Ensure proper and even grinding of rubber blanket .
  51. 51. REFRENCES • Towards zero Defect Amubhai patel • www.textilelerner.com • Major fabric defects during chemical processing • Quality and Process control S.M. Doshi & HA Shah • Chemical technology of fibrous materials - F. Sadov • Technology of Dyeing – V. A. Shenai • www.kyungin.co.kr/eng/sup/page1.htm#list1 • www.textileinfo.com • www.alleycatscratch.com • Critical Solutions In The Dyeing Of Cotton Textile Materials R. Shamey and T. Hussein • Reduction of values in textile industry,(Bombay textile research ass.nov.14 1983) p-23-38.
  52. 52. THANK YOU

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