Dyeing of pet wool blends


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Dyeing of pet wool blends

  1. 1. Minimisation of damage to wool <ul><li>The advantages of high temperature dyeing above 110 0 C are </li></ul><ul><ul><li>Fast deep shades </li></ul></ul><ul><ul><li>Shorter leveling time </li></ul></ul><ul><ul><li>Better levelling </li></ul></ul><ul><ul><li>Less staining of wool </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Wool degradation –reduction in strength, elongation, abrasion resistance, yellowing </li></ul></ul>
  2. 2. <ul><li>Therefore, to protect the wool component during high temperature dyeing, </li></ul><ul><ul><li>Most common agent HCHO (5% owf) allows dyeing at </li></ul></ul><ul><ul><ul><li>105 0 C for 4 hrs </li></ul></ul></ul><ul><ul><ul><li>110 0 C for 3 hrs </li></ul></ul></ul><ul><ul><ul><li>115 0 C for2 hrs </li></ul></ul></ul><ul><ul><ul><li>120 0 C for 1 hr </li></ul></ul></ul><ul><ul><li>pH: 3.5-4.5 </li></ul></ul>
  3. 3. Recommended dyeing times <ul><li>100 0 C for 120-150 min with carrier, no formaldehyde </li></ul><ul><li>106 0 C ,90 –120 min with carrier and without formaldahyde </li></ul><ul><li>110 -115 0 C, 60 –90 min, reduced amount of carrier, formaldehyde necessary </li></ul><ul><li>120 0 C, 20-30 min (not >40 min), carrier optional, formaldehyde necessary </li></ul><ul><li>High temperature dyeing is recommended for deep shades –yellowing is not so critical </li></ul>
  4. 4. Precautions for formaldehyde use <ul><ul><li>Shades of some dyes are affected -careful dye selection </li></ul></ul><ul><ul><li>HCHO vapours are potentially hazardous -restricted use by health and safety considerations </li></ul></ul><ul><li>Therefore, agents which will release HCHO during dyeing (in-situ release) are preferred. E.g DMEU -HCHO release above 0 0 C </li></ul>
  5. 5. Dyeing methods: <ul><li>One bath dyeing method with disperse and acid or metal complex dyes </li></ul><ul><li>Dye selection: </li></ul><ul><ul><li>Disperse dye –low energy ->minimum staining of wool –easily removed by after wash </li></ul></ul><ul><ul><li>Acid or metal complex –not so critical </li></ul></ul>
  6. 6. General dyeing recipe <ul><li>X% disperse dye </li></ul><ul><li>Y% acid/metal complex dye </li></ul><ul><li>Z% carrier </li></ul><ul><li>1 –2% dispersing agent </li></ul><ul><li>5 -10% glauber’s salt </li></ul><ul><li>pH :4.5 –5.5 with acetic acid </li></ul>
  7. 7. Dyeing procedure <ul><li>Set bath with auxuliaries </li></ul><ul><li>Preheat 10 –20 min at 50 -70 0 C </li></ul><ul><li>Add disperse and dissolved acid dye </li></ul><ul><li>Treat for 10 min </li></ul><ul><li>Raise temperature to boil or 103-106 0 C 30-45 min </li></ul><ul><li>Dye for 1½-2hrs depending on depth of shade </li></ul><ul><li>Cool, cold and hot rinse –shading 80 -100 0 C </li></ul>
  8. 8. One-bath dyeing <ul><li>Improve dye exhaustion </li></ul><ul><li>Minimise wool staining </li></ul><ul><li>Wool protecting agent is necessary </li></ul><ul><li>Recipe: </li></ul><ul><ul><li>X% disperse dye </li></ul></ul><ul><ul><li>Y% acid / metal complex dye </li></ul></ul><ul><ul><li>3-5% HCHO (30%) </li></ul></ul><ul><ul><li>1-2% dispersing agent , pH : 5 -6 with HAC’ </li></ul></ul>
  9. 9. <ul><li>Pretreat with auxiliary at 50-60 0 C </li></ul><ul><li>Add disperse and acid dyes </li></ul><ul><li>Treat for 10 min </li></ul><ul><li>Raise temperature to 110 0 C/120 0 C in 45 min </li></ul><ul><li>Dye for 30 –60 min </li></ul>
  10. 10. After treatment <ul><li>Staining of wool with disperse dyes cannot be avoided even if the process is carried out with most siutable dyes under the most favourable conditions </li></ul><ul><li>Disperse staining on wool –poor fastness –must be removed completely </li></ul><ul><li>One-bath method –reduction clear is not possible </li></ul><ul><li>After wash: 1-2 gpl non-ionic detergent, pH 5-6 with HAC’, 20-30 min at 60 0 C, good rinse </li></ul><ul><li>With deep shades, repeat the above process </li></ul>
  11. 11. Two bath process <ul><li>Used for deep shades -particularly navy and black </li></ul><ul><li>Dye polyester component with </li></ul><ul><ul><li>X % disperse dye </li></ul></ul><ul><ul><li>Y% carrier </li></ul></ul><ul><ul><li>1 –2% dispersing agent </li></ul></ul><ul><ul><li>pH 5-6 with HAC’ </li></ul></ul><ul><ul><li>Maximum temperature :103 -106 0 C or boil </li></ul></ul><ul><ul><li>Cold rinse </li></ul></ul>
  12. 12. Reduction clearing: <ul><ul><li>3 gpl hydrose </li></ul></ul><ul><ul><li>0.5- 1 ml/l ammonia(25%) </li></ul></ul><ul><ul><li>0.5-1 gpl non-ionic emulsifying agent </li></ul></ul><ul><ul><li>For 30 min at 45 -50 0 C </li></ul></ul><ul><li>Good rinse, acidify with HAC’ </li></ul><ul><li>Dyeing of wool component </li></ul>
  13. 13. Thermosol dyeing <ul><li>Not common </li></ul><ul><li>Can be used for coloration of PET component only </li></ul><ul><li>Wool component is dyed seperately ( detail sin page 256-257) </li></ul><ul><li>Dry heat treatment: </li></ul><ul><ul><li>190 -200 0 C for 45 –60 secs </li></ul></ul><ul><ul><li>Not harmful to wool except slight yellowing </li></ul></ul><ul><ul><li>Less wool staining </li></ul></ul>
  14. 14. Correction of faulty dyeings <ul><li>Faulty shades can be levelled or partially stripped with </li></ul><ul><ul><ul><li>X gpl carrier </li></ul></ul></ul><ul><ul><ul><li>2-4% levelling agent for wool </li></ul></ul></ul><ul><ul><ul><li>1 –2% emulsifying agent </li></ul></ul></ul><ul><ul><ul><li>pH 5-6% with HAC’ </li></ul></ul></ul><ul><ul><li>Treatment at boil for 1 –2 hrs or 103 -106 0 C for 1 –1 ½ hrs </li></ul></ul><ul><ul><li>If only shade on wool is to be corrected, carrier is not necessary </li></ul></ul>