Knit Processing – SDC Concept
Ashok Athalye & Vinay Jadhav
Technical Service, Atul Ltd (Colors Division), Atul – 396 020, Valsad, Gujarat, India The textile wet processing industry for apparel applications is considered to comprise of three main segments viz, yarn dyeing (including Denim yarn), piece dyeing (including garments) & the Knit dyeing. Recent years have witnessed highest growth in knit or commonly called hosiery processing. In India , this knit processing industry is spread across the country from north to south & east to west. The Indian textile industry can be broadly classified into 2 groups based on working condition, 1. Organized sector- units are well equipped with facilities like water softening (Ion exchange), TDS control (Reverse Osmosis), effluent treatment facility (water discharge/ reuse of treated water), modern machinery with auto control facilities having very high productivity & skilled work force. These units aim at value addition to fulfill stringent global customer requirements.
2. Unorganized sector- units lacking above facilities & using conventional machinery, compromising on quality over cost. This sector mainly aims at producing economical products for low end sector The common wet processing problems associated are generally considered to be due to 3 M’s (Man- MachineMethod) i.e. manual errors, mechanical limitations & inappropriate processing methods. Apart from these there are some geographical or regional issues related to the two basic ingredients i.
The substrate – Variation in cotton fiber cultivated in various regions across the country, in terms of impurities like alkali earth & heavy metal ion content,
Water - its availability, purity & discharge/ recycling.
SDC (Symptoms, Diagnosis & Curing ) Concept
The problems faced during Cotton knit wet processing in these two sectors vary widely owing to the above mentioned reasons like water, fiber sources & processing conditions. However, in order to overcome/ minimize the processing related problems it is essential to first understand the Symptoms (problems), Diagnose (ascertain the probable cause) & Cure (adopting remedial measure).
Given below are some general & common problems encountered in Knit processing & the effectiveness of the ‘SDC’ approach to overcome/minimize these issues. However, it is always advisable to use adequate, appropriate & optimum quality / quantity of Dyestuffs & auxiliary chemicals as per the suppliers recommendations.
DIAGNOSIS / POSSIBLE CAUSE
CURE / POSSIBLE REMEDY
- Overloading of fabric / uneven tube
- Adjust the jet pressure properly &
calculate the weight of fabric to be loaded
based on rope length/ diameter/ gsm of
- Too high jet pressure also leads to
entanglement at the reel & accumulation of
fabric at rear side of the machine.
- Use of surfactants like Tulachem
Hyperwet RW a very low foaming
detergent having optimum adsorption &
- Improper (low or very high) jet
pressure, reduced nozzle aperture
- Foaming due to detergent, emulsifier,
rapid decomposition of Peroxide,
lubricant used during knitting or other
surfactant chemicals causing foaming.
absorption for quick wetting, emulsification
& detergency for thorough oil/soil removal
& rewetting absorbency .
- Use of a non foaming alkali stable anticrease lubricant like Tulachem Texlube AC
- Controlled heating during peroxide
dosing & adequate organo-inorganic
bleach controller like Tulachem
-Addition of a deareating/ penetrating
agent like Tulachem Texflow DAP.
Oil marks on fabric
- Inadequate emulsification/ removal of
- Improper removal of Silicone oil from
Elastane/ lycra blends
- Use of a strong emulsifier for knitting oil
removal like Tulachem Wettex SRL
- After every process, if possible check
filter & clean it.
Pin hole damage
- Oxidation of the knitting...
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