DENIM PROCESS SIMPLIFIED: FROM FIBRE TO FABRIC
Denim process begins with the spinning of raw cotton to cotton yarn. Hundred percent cotton still remains the preferred fabric despite attempts made by denim manufacturers in India and abroad to introduce union denims which has not found any wide acceptance either in the international or Indian market. Spinning is followed by dyeing of warp yarn to required shades and other weaving preparatory treatments like sizing etc. The yarn is woven into fabric and the fabric is subjected to various finishing processes. The finished material is then checked, packaged and delivered to customers. The production of fabric mainly involves spinning, dyeing and sizing, weaving and processing.
TABLE 2.1 : DENIM PRODUCTION TECHNOLOGIES
CHOICE OF TECHNOLOGY & THE PROCESS SEQUENCE
Open End Spinning – v – Ring Spinning
Denim plants have both open-end and ring denim capabilities, although a majority of the capacities are open-end, which historically cater to mass-market denim products. However, open-end plants are also able to manufacture specialty denim fabric with changes to their processes. Ring spun denim is of a higher quality and commands higher prices in the denim fabric market. The process sequence of OE and ring spinning are given in the following Table 2.2
TABLE 2.2 : SPINNING – PROCESS SEQUENCE
The rope method is generally used in the mass production of fabrics with set specifications. The slasher method is generally used in smaller scale production of fabrics and allows for modification of specifications. Rope-dyeing technology provides a uniform dye to denim fabric when compared to the slasher-dyeing process. Steps involved in the Slasher Process and Rope process are as follows:
TABLE 2.3 : DYEING – PROCESS SEQUENCE
Wet and Foam Finishing
While application and distribution of chemicals is quite uniform in wet finishing, the practical alternative to reduce energy bill is to use foam technology. The foam finishing is environmentally-friendlier and reduces pollution. The Table below depicts the process sequence adopted.
TABLE 2.4 : FINISHING – PROCESS SEQUENCE