HOW FOAM DYE­ING PROCESS TAKES PLACE…

Stitch World - - SUSTAINABILITY -

The foam dye­ing tech­nol­ogy con­sist of three se­quen­tial cham­bers: the purge cham­ber, ap­pli­ca­tion cham­ber and ki­netic cham­ber so as to en­sure anaer­o­bic en­vi­ron­ment for dye­ing.

Purge Cham­ber re­moves oxy­gen from the yarns be­fore en­ter­ing into the ap­pli­ca­tion cham­ber. This elim­i­nates the use of sul­phur re­duc­ing com­pounds which are pri­mar­ily used dur­ing the con­ven­tional wet dye­ing.

Ap­pli­ca­tion Cham­ber con­trols the delivery of foam­based dye liquor to de­liver the dye liq­uid from the col­lapsed foam. It en­ables the con­trol of dye up­take and pen­e­tra­tion.

Ki­netic Cham­ber is mainly re­spon­si­ble for mod­u­lat­ing dye ab­sorp­tion so as to min­imise the amount of detri­men­tal sur­face indigo as well as wasted indigo. It also en­hances the dark­ness of blue colour and improves the colour-fast­ness prop­erty.

For re­li­able foam dye­ing process along with the cham­bers, there should be a yarn han­dling sys­tem. Since yarns do not be­have as struc­tured fab­ric, thus in this case, foam dye­ing tech­nique is highly ef­fec­tive along with the re­ac­tive and other nonox­i­dis­ing dyestuff. Con­sis­tent qual­ity re­quires con­sis­tent con­trol of both yarns as well as foam.

The yarn han­dling sys­tem is re­spon­si­ble for de­liv­er­ing yarns from a small beam through the dye­ing sys­tem and rewind­ing the dyed yarns onto an­other beam. It pro­vides com­put­erised con­trol of yarn ten­sions from the be­gin­ning to end. Also a yarn creel with com­put­erised con­trol of yarn ten­sions is at­tached to the sys­tem just to en­sure the yarn pack­ages are con­sis­tently fed into the yarn han­dling sys­tem.

The sys­tem also con­tains a foam gen­er­a­tor for fab­ri­ca­tion. The gen­er­a­tor de­liv­ers me­tered foam di­rectly on the sheets when it passes over a se­quence of rollers. It is con­nected with the yarn han­dling sys­tem so that con­stant yarn ten­sion is main­tained through­out. It also en­ables real-time ad­just­ment of the foam blow ra­tios as well as wet pick-up lev­els.

The ox­i­da­tion and the dry­ing rack which is present in­be­tween the ki­netic cham­ber and the yarn take-up beam is mainly re­spon­si­ble for the ox­i­da­tion process of the dyed yarns. Yarns need time to ox­i­dise be­fore dry­ing as mois­ture is re­quired for ox­i­da­tion to take place. The process of ox­i­da­tion hap­pens quite rapidly and the de­sign of the rack is ad­e­quate enough even when run­ning at high speed.

Royo stated that it is a sys­tem that is en­tirely free of wa­ter, that is, a dry dye­ing process in which indigo is ap­plied us­ing foam. This breath­tak­ing tech­nol­ogy not only saves wa­ter but also cuts down on the con­sump­tion of chem­i­cals by 90 per cent. What is more, en­ergy con­sump­tion is also re­duced tremen­dously. He added that the fu­ture of indigo dye­ing lies in sus­tain­able pro­duc­tion.

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