Dyeing of aramid fibers


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Dyeing of aramid fibers

  2. 2. What are aramid fibers These are also called aromatic polyamides Those polyamides,which have aromatic six carbon rings in polymeric chain
  3. 3. Main types of aramid fibers Technora (made by Teijin of Japan) Conex (made by Teijin) Kevler (made by Dupont) Nomex (made by Dupont)
  4. 4. Good Qualities of fibers Good heat resistance High tenacity & modulus of rigidity Non flammability Greater sticking temperature Aramid dominate over glass fibers,and carbon fibers in all over the world market Stiffest &Toughest than even carbon and steel
  5. 5.  High modulus five times greater than polyester Excellent in tension Good chemical resistance Compactness and solidity of molecular structure In dry air,at 260C Aramid shrink only 2% By Sputter etching, depth of shade increased considerably
  6. 6. DISADVENTAGES No substantivity to dyes No environment friendly Poor UV resistance Rapid loss of strength with flexing ,folding &flogging Low light fastness,even spun dyed yarn Very expensive Poor in compression than glass
  7. 7. Main physical properties Melting poit371C Tenacity 5.3gmden at 65%RH&70F Specific gravity of fiber is 1.38 Tg 275C
  8. 8. Dying of nomex with Basic dyes Fiber (2dtex50mm) Fabric form GSM (265gmWashingNomex in fiber form are washed in Vald henriksen FBK MACHINE.In fabric form,Walter Franke dying apparatus
  9. 9. Recipe for washing Nonionic surfactant 1gl Trisodiun phosphate dodecahydrate1gl Liqour ratio 30:1 Washing condition Start at 40C &temperature raised to80C for 30 min Rinsing with hot and cold for 10 min
  10. 10. Dying procedure Polycolor zeltex AG machine, used for dying Resipe Dye 2% o.w.f (Special dye, CI Basic 41) Sodium nitrate 20gl Career benzyl alcohol 70 gl Acetic acid 2.5gl (60%) Liqour ratio 20:1
  11. 11. After treatment process Materials are treated with 2gl nonionic surfectant for 20 min at 95C Acetic acid added to maintain PH to 3 Hot &cold rinsing Fixation was carried out fir 30sec at 200C
  12. 12. Dyeing of Technora and conex with disperse dyesThree commercial disperse dyes are used1)Terasel yellow3GW(CI Disperse yellow54)2)resolin red FB(CI Disperse Red 60)3) Resolin blue FB (CI Disperse blue56)DYING CONDITIONTemperature 190 &time 60 minDying machineMini –colour (Texam GIKEN)
  13. 13. Recipe Disperse dye (4-24%o.w.f) Dispersing agent (Disper VG) Nonionic surfectant 0.5gl Acetic acid 0.2gl & PH to4.2 Liqour ratio15:1 Dying temp is raised at 2degCmin Maintaining temp to 190C for 60 min Reduction clearing is carried out twice
  14. 14. Dyeing of Nomex type430filament yarn Three commercial basic dyes are use for dying CI Basic blue54 (CIBB-54) CI Basic red29 (CIBR-29) CI Basic redGL22(CIBR22) Dyeing Procedure Weight of skein of yarn(2.5) Infinite Liqour ratio140:1 Commercial dyestuff (10% o.w.f)
  15. 15.  Using no career Temperature of dying range of 80 to 100C
  16. 16. Approaches to improve dyebility of aramid fibers More polar solvent Pretreatment of liquid ammonia Using benzyl alcohol as carrier
  17. 17. Pretreatment with liquid ammonia Pretreatment fibers with liquid ammonia,substantivity towards basic dye increase quite significantly Condition of pretreatment process Immersing 2.5g m-aramid in 100ml liquid ammonia Time 10 min &at 40 C Rinsing with hot and cold water
  18. 18. Dependence of light fastness properties on pretreatment & dyeing procedure CI Basic fastness to light A B C Yellow 28 3 3-4 4-5 Orange 22 1 3 4 Red46 1 2 3 Red29 1 4 4-5 Blue 49 1 3-4 3-4 A : Without pretreatment, dyed without career B : Without pretreatment,dyed with 70 gl benzyl alcohol C : Pretretment with liquid ammonia,dyed without carrier
  19. 19. Conclusion Pretreatment of aramid fibers with liquid ammonia can not only increase substantivity for basic dyes,but also light fastness properties, as comparing with those of fibers dyed conventionally with basic dyes using career benzyl alcohol
  20. 20. Effect of polar solvent on dyebility of aramid fiber These are three high polar solvents Dimethyl formamide Dimethyl acetate Dimethyl sulfoideThese solvents provide chemical energy to fibers,permitting rearrangement of the polymer chain through breakage and reformation of interchain hydrogen bonding
  21. 21. Factor of changing solvent diffusion in nomex fiber 1)Molecular volumeMol vol = Mol.wtr * 10 24NWhere r is densityN is Avogedro number2)Temperature of corresponding to onset of shrinkage.
  22. 22. Exhaust dyeing of treated nomex yarns Exhaustion of CIBB54 at 100C At 30 min Attaining max degree of structural modification Order of increasing exhaustion rate DMF<DMAc<DMSO In DMF,90% of dye liquor being exhausted after 4hours In DMAc&DMSO leads to very rapid exhaustion 95% of dye liquor being exhausted in 45 minutes
  23. 23.  Untreated yarns dyed according to commercial dying procedure in presence of Dymex career resulted in low exhaution45% of dye liquor Temperature dependence of exhaustion rate With DMF A slight decrease in rate occurs when treatment temperature decreases from 100 to 50C Considerable larger decrease in rate occurs on reducing temp of treatment to further to 40C With DMAc major change in exhaustion rate occurs between samples treated at 82.2&75C
  24. 24. Influence of treatment time on exhaustion rate An increase in treatment time, leads to faster exhaustion rate Temp from 30 sec to 30 min,solvent diffusion And polymer interaction are considerably faster But exhaustion rate is unaffected Structural modification changes also depends on treatment time
  25. 25. Conclusion Optimum condition of dying 100c and 30 minutes then substrate is readily dyeable in atmosphere pressure After solvent treatment ,loss of polymer chain orientation and or formation of void takes place Solvent treated fabric leads to attain greater dyebility at expense of initial modulus and tensile strength Elimination of larger amount of careers
  26. 26.  Lower dyeing temperature and shorter dyeing time (significant benefit)
  27. 27. Effect of varying liquid ammonia pretreatment time &dying temppretreatment Dying KS Wash fast-time temp VALUE -ness inC0.2 130 12.1 3-45 130 12.4 3-410 130 10.8 3-430 130 11.0 3-430 100 10.6 3-4
  28. 28.  Method of removing ammonia Rinsing Rinsing &drying Evaporation without rinsing Treatment Tensile strength Extension step mNtex (%) A 270 48 B 230 64 C 213 47 D 222 27 E 243 43 A Raw fiber B; Pretreatment 15 min in liquid ammonia C; Pretreated fiber dyed with basic dye D; Untreated fiber dyed with basic dye using benzyl alcohol E; Untreated fabric dyed with basic but without career( Effect of pretretment and dying method on fiber strength and extension)
  29. 29. Influence of sputter etching in shade of dyed fabrics The aramid fabric Technora dyed with CI Disperse54 etc, are treated by sputter etching and argon low-temperature plasma Sputter etching is effective I increasing color depth of dyed Technora As a decrease of L* for blue and red dyeing and considerable increase in C*for all three colors These effects on dyed Technora are slightly less with low temperature plasma treatment
  30. 30.  No significant effect on CONEX FABRIC Basic purpose of sputter etching is to produce deeper shade deeper and or more vivid colors on dyed aramid fabric without actually increasing concentration dye Technora caused by sputter etching is thought to be due to formation of Microcrates during treatment that severely restrict the reflection of incident light
  31. 31.  Name of device used for sputter etching, Shinku-kiku RFS-200 Depth of shade is measured with colorEye MS2020 Spectrophotometer under illuminant D65 AND WITH 10 OBSERVER Spectrophotometer calculate value lightness L* and color difference E in CIELAB color space CONDITION OF SPUTTER ETCHING Pressure of 20 pa Power rating of 100 Wt Time of treatment from 30 to 300sec
  32. 32. References JSDC Volume111 Mach 1995,page72 JSDC Volume 111 March 1995 ,page 111 TRJ April 1986, page 254 JSDC Volume 110 JulyAug , page228,1994 Encyclopedia of textile finishing by H.K.ROUETTE Man made fibers, page408 By R.W.Moncrieff www.dupont product.com