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New green chemical techniques in textile coloration processes   Dr. Richard S. Blackburn Senior Lecturer and Head of Green...
Where can Green Chemistry have an impact in Coloration? <ul><li>Dye chemistry </li></ul><ul><ul><li>Alternative synthesis,...
Sustainable platform chemicals <ul><li>Natural dyes derived from plant material represent a more sustainable source of col...
Sustainable platform chemicals <ul><li>Derivatisation of alizarin to produce more hydrophobic molecule </li></ul><ul><ul><...
Sustainable platform chemicals <ul><li>Problem with application of alizarin is pH sensitivity </li></ul><ul><li>1H2EA disp...
Sustainable platform chemicals <ul><li>Dyes applied with dispersing agent to PET and PLA </li></ul><ul><li>Colour strength...
 
Sustainable platform chemicals <ul><li>Wash fastness comparable and excellent on all dyeings </li></ul><ul><li>Light fastn...
Green Chemistry Sulphur Dyeing <ul><li>Economical, good colour strength, good fastness dyeings on cellulosics </li></ul><u...
Mechanism of sulphur dyeing <ul><li>Initially dye is in insoluble oxidised (pigment) form </li></ul><ul><li>Addition of re...
Reducing agents in sulphur dyeing <ul><li>Sulphur dyes themselves have a relatively low detrimental environmental impact <...
Alternative reducing agents <ul><li>Thiourea dioxide from both a practical and ecological point of view </li></ul><ul><ul>...
Application of various reducing  D -sugars <ul><li>D -arabinose </li></ul><ul><li>D (-)-fructose </li></ul><ul><li>D (+)-g...
D -arabinose D (-)-fructose D (+)-galactose α - D -glucose
D -maltose β - D -lactose
Environmental and economical considerations Relative theoretical COD and price of reducing agents per kg dyed cotton a  Ba...
Greener reactive dyeing of cellulose <ul><li>Treatment of cellulose with cationic, nucleophilic polymers to enable reactiv...
Problems with high electrolyte concentration <ul><li>High levels of salt (sodium sulfate/chloride) used when dyeing cotton...
Mechanism of reactive dye fixation to cellulose (Nucleophilic substitution)
Mechanism of reactive dye fixation to cellulose (Michael Addition)
Colour (unfixed dye) in effluent <ul><li>Reactive dyes poor fixation </li></ul><ul><ul><li>10-40% dyestuff hydrolysed </li...
High water consumption <ul><li>High level of water used in reactive dyeing </li></ul><ul><li>Incredible volume used in was...
Pre-treatment agents Copolymer of diallyldimethylammonium chloride and 3-aminoprop-1-ene (PT1) Copolymer of 4-vinylpyridin...
High substantivity of pre-treatments for cotton <ul><li>Both pre-treatment polymers are highly substantive to cellulosic f...
PT1 Conformational interaction between PT1 and cellulose
PT2 <ul><li>Ion-dipole interactions between cellulose hydroxyl groups and pyridinium residues of PT2 </li></ul><ul><li>Yos...
Mechanism of operation (schematic)
Advantages of pre-treatment system <ul><li>Polymers cationic </li></ul><ul><ul><li>No requirement for salt </li></ul></ul>...
System comparison pre-treatment (10), detergent (20) 0 0 0 50 195 1 Pre-treatment acetic acid (60), detergent (20) 500 150...
Publications <ul><li>Blackburn, R. S.; Burkinshaw, S. M.  Green Chemistry  2002  4  (1), 47. </li></ul><ul><li>Blackburn, ...
DyeCat Ltd. <ul><li>A University of Leeds Spinout Company </li></ul><ul><li>Dr. Patrick McGowan </li></ul><ul><ul><li>Orga...
DyeCat Technology <ul><li>Patented technology for the preparation of light absorbing polymeric materials (IR, visible, UV)...
Contacts <ul><li>Laura Bond (general inquiries) </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>Dr. Patrick M...
Acknowledgements <ul><li>Colleagues </li></ul><ul><ul><li>Prof. Chris Rayner </li></ul></ul><ul><ul><li>Prof. Tony Cliffor...
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Wun Presentation

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  1. 1. New green chemical techniques in textile coloration processes Dr. Richard S. Blackburn Senior Lecturer and Head of Green Chemistry Group Centre for Technical Textiles UNIVERSITY OF LEEDS, LS2 9JT, UK [email_address]
  2. 2. Where can Green Chemistry have an impact in Coloration? <ul><li>Dye chemistry </li></ul><ul><ul><li>Alternative synthesis, sustainable source, natural platform chemicals </li></ul></ul><ul><li>Dyes in effluent </li></ul><ul><ul><li>Reduction (efficiencies of sorption) and cleaner treatment technologies </li></ul></ul><ul><li>Auxiliary chemicals </li></ul><ul><ul><li>Reduction in use and emission of harmful auxiliaries ( e.g. salt, reducing agents, carriers) </li></ul></ul><ul><li>Application processes </li></ul><ul><ul><li>Reduction in energy, water usage, time </li></ul></ul><ul><li>Coloration of ‘greener’ fibres </li></ul><ul><ul><li>PLA, PHAs, lyocell, etc . </li></ul></ul>
  3. 3. Sustainable platform chemicals <ul><li>Natural dyes derived from plant material represent a more sustainable source of colorants </li></ul><ul><li>Natural dyes colour natural fibres (cotton, wool, silk) to a greater or lesser extent </li></ul><ul><ul><li>need application with a mordant (salts of Cr, Sn, Zn, Cu, Al, Fe) to secure sufficient wash and light fastness and to give good build-up </li></ul></ul><ul><li>Natural dyes have found limited success in coloration of synthetic fibres </li></ul><ul><ul><li>PET has a 45% share of the global textile market </li></ul></ul><ul><li>Madder plant ( Rubia tinctorum L. ) is an important dye plant </li></ul><ul><ul><li>produces the dye alizarin (1,2-dihydroxyanthraquinone) </li></ul></ul><ul><ul><li>also contains rubiadin (1,3-dihydroxy-2-methylanthraquinone) and purpurin (1,2,4-trihydroxyanthraquinone) </li></ul></ul>
  4. 4. Sustainable platform chemicals <ul><li>Derivatisation of alizarin to produce more hydrophobic molecule </li></ul><ul><ul><li>higher affinity for hydrophobic polyesters </li></ul></ul><ul><li>Successful synthesis of 1-hydroxy-2-ethylanthraquinone (1H2EA) </li></ul><ul><ul><li>93% yield </li></ul></ul><ul><ul><li>confirmed by FT-IR and NMR </li></ul></ul><ul><ul><li>OH at 1-position not derivatised due to intramolecular hydrogen bond formation and lower intrinsic reactivity </li></ul></ul>
  5. 5. Sustainable platform chemicals <ul><li>Problem with application of alizarin is pH sensitivity </li></ul><ul><li>1H2EA displays no such sensitivity due to derivatisation of 2-OH </li></ul>Table: The effect of pH on solubility and colour of alizarin and 1H2EA insoluble no colour v. sparingly soluble no colour 4 insoluble no colour soluble purple colour 10 insoluble no colour sparingly soluble orange/yellow colour 7 1H2EA Alizarin pH
  6. 6. Sustainable platform chemicals <ul><li>Dyes applied with dispersing agent to PET and PLA </li></ul><ul><li>Colour strength (K/S) achieved with 1H2EA higher than alizarin </li></ul><ul><li>Dyeings unlevel, poor quality with alizarin </li></ul><ul><li>Dyeings level, bright, good quality with 1H2EA </li></ul><ul><li>Alizarin gives higher K/S on PET w.r.t. PLA, but opposite observed for 1H2EA </li></ul><ul><ul><li>increased interactions with PLA via alkyl chain addition </li></ul></ul>Table: Colour strength (K/S) values of dyed samples   20.9   19.2 4% omf at 130 °C 10.6   2.2   4% omf at 115 °C   8.7   6.5 1% omf at 130 °C 5.1 4.3 2.1 3.1 1% omf at 100 °C 4.3   1.5   1% omf at 90 °C PLA PET PLA PET 1H2EA Alizarin Conditions of application
  7. 8. Sustainable platform chemicals <ul><li>Wash fastness comparable and excellent on all dyeings </li></ul><ul><li>Light fastness considerably higher for 1H2EA compared to alizarin </li></ul><ul><ul><li>2-OH susceptible to photo-oxidation, as it cannot form an intra-molecular H-bond </li></ul></ul><ul><ul><li>In 1H2EA 2-OH derivatised, so not as susceptible to photo-oxidation </li></ul></ul>Table: Light fastness of dyed samples (1-8 scale)   6   5 4% omf at 130 °C 6   3/4 4% omf at 115 °C   6   4 1% omf at 130 °C 5/6 6 3 3 1% omf at 100 °C 5   3   1% omf at 90 °C PLA PET PLA PET 1H2EA Alizarin Conditions of application
  8. 9. Green Chemistry Sulphur Dyeing <ul><li>Economical, good colour strength, good fastness dyeings on cellulosics </li></ul><ul><li>Significant share of the colorants market </li></ul><ul><ul><li>annual consumption of ca. 70,000 tons </li></ul></ul><ul><li>C. I. Sulphur Black 1 alone represents a substantial portion (20-25%) of dyestuff market for cotton </li></ul><ul><ul><li>highest consumption of any single textile dye in the world </li></ul></ul><ul><li>Complex mixtures of reproducible, but uncertain, compositions </li></ul><ul><li>Contain within their ring structure thiazole, thiazone, or thianthrene as chromophores </li></ul><ul><li>All sulphur dye molecules contain disulfide linkages </li></ul>
  9. 10. Mechanism of sulphur dyeing <ul><li>Initially dye is in insoluble oxidised (pigment) form </li></ul><ul><li>Addition of reducing agent cleaves a proportion of the disulfide linkages to form the partially soluble ‘leuco’ sulphur form </li></ul><ul><li>Further addition of reducing agent and increase in redox potential causes reduction of the remaining disulfide linkages and quinoneimine groups </li></ul><ul><li>After exhaustion of the dye onto fibre, the reduced, adsorbed dye is reformed in situ within the fibre by air or chemical oxidation </li></ul>
  10. 11. Reducing agents in sulphur dyeing <ul><li>Sulphur dyes themselves have a relatively low detrimental environmental impact </li></ul><ul><ul><li>free from heavy metals and AOX </li></ul></ul><ul><li>Significant environmental problem with the dyeing process </li></ul><ul><ul><li>employ sulfides as reducing agents </li></ul></ul><ul><ul><li>90% of all sulphur dyes are reduced using sodium sulfide </li></ul></ul><ul><li>Discharge of sulfides only permissible in very small amounts (usually the legal allowance is 2 ppm) </li></ul><ul><ul><li>danger to life from liberated hydrogen sulfide </li></ul></ul><ul><ul><li>corrosion of sewerage systems </li></ul></ul><ul><ul><li>damage to treatment works </li></ul></ul><ul><ul><li>high pH </li></ul></ul><ul><ul><li>aquatic life down stream significantly affected </li></ul></ul><ul><ul><ul><li>damage to the DNA of tadpoles </li></ul></ul></ul><ul><ul><li>classed as micropollutants </li></ul></ul><ul><ul><li>over time the substance can reach high concentrations </li></ul></ul>
  11. 12. Alternative reducing agents <ul><li>Thiourea dioxide from both a practical and ecological point of view </li></ul><ul><ul><li>dyeings comparable, but environmental effect unclear </li></ul></ul><ul><ul><li>significantly more expensive than sodium sulfides </li></ul></ul><ul><li>Indirect cathodic reduction processes </li></ul><ul><ul><li>successfully reduce sulphur dyes </li></ul></ul><ul><ul><li>some reducing agent was required to prevent premature re-oxidation of the dye </li></ul></ul><ul><ul><li>dyeing was comparable </li></ul></ul><ul><ul><li>electrolysis is an appreciably more expensive technology </li></ul></ul><ul><li>Glucose/NaOH </li></ul><ul><ul><li>above 90°C has sufficient reducing potential </li></ul></ul><ul><ul><li>no current systems in commercial use </li></ul></ul><ul><ul><li>dyeings secured had lower colour strength and fastness </li></ul></ul><ul><ul><li>no fundamental work on the reducing sugar/NaOH system conducted to understand optimum </li></ul></ul>
  12. 13. Application of various reducing D -sugars <ul><li>D -arabinose </li></ul><ul><li>D (-)-fructose </li></ul><ul><li>D (+)-galactose </li></ul><ul><li>α- D -glucose </li></ul><ul><li>β- D -lactose </li></ul><ul><li>D -maltose </li></ul><ul><li>sodium polysulfide </li></ul><ul><li>sodium hydrosulfide </li></ul>Blackburn, R. S.; Harvey, A. Env. Sci. Technol. 2004 , 38 (14), 4034.
  13. 14. D -arabinose D (-)-fructose D (+)-galactose α - D -glucose
  14. 15. D -maltose β - D -lactose
  15. 16. Environmental and economical considerations Relative theoretical COD and price of reducing agents per kg dyed cotton a Based on 2.5 g dm -3 reducing agent (typical optimum concentration) at a liquor ratio of 25:1 4.30 70.1 D -maltose 2.08 70.1 β- D -lactose 0.58 66.6 α- D -glucose 4.14 66.6 D (+)-galactose 1.65 66.6 D (-)-fructose 28.06 66.6 D -arabinose 1.18 71.3 sodium hydrosulfide 1.60 51.3 sodium sulfide £ kg -1 dyed cotton a g O 2 kg -1 dyed cotton a Reducing agent
  16. 17. Greener reactive dyeing of cellulose <ul><li>Treatment of cellulose with cationic, nucleophilic polymers to enable reactive dyeing at neutral pH without electrolyte addition </li></ul><ul><li>Reactive dyeing problems </li></ul><ul><ul><li>High electrolyte concentrations used </li></ul></ul><ul><ul><li>High colour concentrations in effluent </li></ul></ul><ul><ul><li>High volume of water consumed </li></ul></ul>
  17. 18. Problems with high electrolyte concentration <ul><li>High levels of salt (sodium sulfate/chloride) used when dyeing cotton </li></ul><ul><ul><li>Particularly reactive dyes </li></ul></ul><ul><ul><li>Fibre has negative charge in water </li></ul></ul><ul><ul><li>Repels anionic dyes – low adsorption </li></ul></ul><ul><ul><li>Electrolyte screens negative charge </li></ul></ul><ul><ul><li>Overcomes repulsion between dye anions and negative fibre surface to allow adsorption </li></ul></ul><ul><li>Soil too alkaline to support crops </li></ul><ul><li>Kills aquatic life </li></ul><ul><li>Examples of fresh water courses turned saline downstream from reactive dyeing operations </li></ul><ul><li>Difficult to remove from effluent </li></ul>
  18. 19. Mechanism of reactive dye fixation to cellulose (Nucleophilic substitution)
  19. 20. Mechanism of reactive dye fixation to cellulose (Michael Addition)
  20. 21. Colour (unfixed dye) in effluent <ul><li>Reactive dyes poor fixation </li></ul><ul><ul><li>10-40% dyestuff hydrolysed </li></ul></ul><ul><ul><li>Goes down drain </li></ul></ul><ul><ul><li>Aesthetically unpleasant </li></ul></ul><ul><ul><li>Blocks sunlight </li></ul></ul><ul><ul><ul><li>Algae overpopulate </li></ul></ul></ul><ul><ul><ul><li>Reduction in O 2 levels in water </li></ul></ul></ul><ul><ul><ul><li>Suffocation of flora and fauna in watercourses </li></ul></ul></ul><ul><li>Clean effluent </li></ul><ul><ul><li>High cost </li></ul></ul>
  21. 22. High water consumption <ul><li>High level of water used in reactive dyeing </li></ul><ul><li>Incredible volume used in wash-off of hydrolysed dye </li></ul><ul><ul><li>Up to 10 separate rinsings </li></ul></ul><ul><ul><li>High energy consumption </li></ul></ul><ul><ul><li>50% total cost dyeing procedure </li></ul></ul>
  22. 23. Pre-treatment agents Copolymer of diallyldimethylammonium chloride and 3-aminoprop-1-ene (PT1) Copolymer of 4-vinylpyridine quaternised with 1-amino-2-chloroethane (PT2)
  23. 24. High substantivity of pre-treatments for cotton <ul><li>Both pre-treatment polymers are highly substantive to cellulosic fibre </li></ul><ul><li>ion-ion interactions between cationic groups in the agent and the anionic carboxylic acid groups in the substrate </li></ul><ul><ul><li>low pK a values will be ionised at the pH values of application (pH 6-7) </li></ul></ul><ul><li>Other forces of attraction </li></ul><ul><ul><li>H-bonding, van der Waals </li></ul></ul>
  24. 25. PT1 Conformational interaction between PT1 and cellulose
  25. 26. PT2 <ul><li>Ion-dipole interactions between cellulose hydroxyl groups and pyridinium residues of PT2 </li></ul><ul><li>Yoshida H-bonding between cellulose hydroxyl groups and pyridine residues in PT2 </li></ul>
  26. 27. Mechanism of operation (schematic)
  27. 28. Advantages of pre-treatment system <ul><li>Polymers cationic </li></ul><ul><ul><li>No requirement for salt </li></ul></ul><ul><li>Nucleophiles in polymer more reactive than hydroxyl groups in fibre </li></ul><ul><ul><li>Neutral pH of application </li></ul></ul><ul><ul><li>Hydrolysis minimised </li></ul></ul><ul><ul><li>Colour fixation yield maximised </li></ul></ul><ul><ul><li>Less colour in effluent </li></ul></ul><ul><ul><li>Less wash-off requirement </li></ul></ul><ul><ul><li>Significant reduction in operation time </li></ul></ul><ul><ul><li>Significant reduction in water consumption </li></ul></ul>
  28. 29. System comparison pre-treatment (10), detergent (20) 0 0 0 50 195 1 Pre-treatment acetic acid (60), detergent (20) 500 1500 0 125 295 5 Cibacron F detergent (20) 500 0 1625 105 365 4 Procion H-EXL acetic acid (60), detergent (20) 500 1250 0 145 355 6 Remazol RR Other Chemicals (g/kg fabric) Na 2 CO 3 (g/kg fabric) Na 2 SO 4 (g/kg fabric) NaCl (g/kg fabric) Water ( ℓ /kg fabric) Time (mins) Wash-off stages Procedure
  29. 30. Publications <ul><li>Blackburn, R. S.; Burkinshaw, S. M. Green Chemistry 2002 4 (1), 47. </li></ul><ul><li>Blackburn, R. S.; Burkinshaw, S. M. Green Chemistry 2002, 4 (3), 261. </li></ul><ul><li>Blackburn, R. S.; Burkinshaw, S. M. Journal of Applied Polymer Science , 2003, 89 , 1026-1031. </li></ul><ul><li>“ Dye Hard”, New Scientist , 1 st December 2001 </li></ul><ul><li>“ Greener Dyes”, The Alchemist , 6 th February 2002 </li></ul><ul><li>“ Problem Fixed”, Chemistry in Britain , April 2002 </li></ul>
  30. 31. DyeCat Ltd. <ul><li>A University of Leeds Spinout Company </li></ul><ul><li>Dr. Patrick McGowan </li></ul><ul><ul><li>Organometallic chemistry </li></ul></ul><ul><ul><li>Novel polymerisation catalysts </li></ul></ul><ul><ul><li>Organometallic anticancer drugs </li></ul></ul><ul><li>Dr. Richard Blackburn </li></ul><ul><ul><li>Coloration of natural and synthetic polymers and fibres </li></ul></ul><ul><ul><li>Physical organic chemistry of dyeing processes </li></ul></ul><ul><ul><li>Green Chemistry in the textile and coloration industries </li></ul></ul><ul><li>Prof. Chris Rayner </li></ul><ul><ul><li>Organic synthesis (pharmaceuticals and fine chemicals) </li></ul></ul><ul><ul><li>Supercritical carbon dioxide </li></ul></ul><ul><ul><li>Green Chemistry </li></ul></ul>©DyeCat 2006
  31. 32. DyeCat Technology <ul><li>Patented technology for the preparation of light absorbing polymeric materials (IR, visible, UV). </li></ul><ul><li>Variety of approaches; allows flexibility in </li></ul><ul><ul><li>Polymer composition </li></ul></ul><ul><ul><li>Polymer molecular weights and polydispersities </li></ul></ul><ul><ul><li>Coloration strength </li></ul></ul><ul><ul><li>Range of light absorbing chromophores </li></ul></ul><ul><li>Applicable to natural and synthetic polymers (particularly polyesters such as PLA and PET). </li></ul><ul><li>Superior coloration technology </li></ul><ul><ul><li>Homogeneous colorant throughout cross section of polymer </li></ul></ul><ul><ul><li>Increased wash and light fastness </li></ul></ul><ul><li>Greatly improved preparative method </li></ul><ul><ul><li>Significant cost reductions on comparable conventional technology </li></ul></ul><ul><ul><li>Reduced environmental impact </li></ul></ul><ul><li>Applicable to sustainable, biodegradable polymers such as PLA and PHB. </li></ul>©DyeCat 2006
  32. 33. Contacts <ul><li>Laura Bond (general inquiries) </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>Dr. Patrick McGowan </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>Dr. Richard Blackburn </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>Prof. Chris Rayner </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><li>www.dyecat.com </li></ul>©DyeCat 2006
  33. 34. Acknowledgements <ul><li>Colleagues </li></ul><ul><ul><li>Prof. Chris Rayner </li></ul></ul><ul><ul><li>Prof. Tony Clifford </li></ul></ul><ul><ul><li>Prof. Stephen Burkinshaw </li></ul></ul><ul><ul><li>Prof. Carl Lawrence </li></ul></ul><ul><ul><li>Prof. Paul Knox </li></ul></ul><ul><ul><li>Dr. Patrick McGowan </li></ul></ul><ul><ul><li>Dr. Steve Russell </li></ul></ul><ul><ul><li>Dr. Abbas Dehghani </li></ul></ul><ul><li>Research Assistants </li></ul><ul><ul><li>Dr. Tony Blake </li></ul></ul><ul><ul><li>Dr. Nagitha Wijayathunga </li></ul></ul><ul><ul><li>Dr. Xiangfeng Zhao </li></ul></ul><ul><li>PhD Students </li></ul><ul><ul><li>Iram Abdullah </li></ul></ul><ul><ul><li>Nabeel Amin </li></ul></ul><ul><ul><li>Ioannis Drivas </li></ul></ul><ul><ul><li>Parikshit Goswami </li></ul></ul><ul><ul><li>Anna Harvey </li></ul></ul><ul><ul><li>Andrew Hewitt </li></ul></ul><ul><ul><li>Nandan Kumar </li></ul></ul><ul><ul><li>Wei Zhang </li></ul></ul><ul><li>Industrial Partners </li></ul><ul><ul><li>Body Shop International plc (UK) </li></ul></ul><ul><ul><li>DyStar (Germany) </li></ul></ul><ul><ul><li>Lenzing Fibers Ltd. (Austria) </li></ul></ul><ul><ul><li>NatureWorks LLC (USA) </li></ul></ul><ul><ul><li>Reilly Industries inc. (USA) </li></ul></ul><ul><ul><li>Uniqema (UK) </li></ul></ul>
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