1 Introduction 7
2 Manufacturing Process 15
3 Denim Washing 37
4 Market Condition 46
5 Denim Manufacturers 51
6 Denim Buyers 56
7 Denim Products 59
8 Buying Solutions 63
9 Conclusion 66
Introduction 1 8
A popular conception of the etymology of the word denim is that it is a contraction or derivative of the French term, serge de Nîmes. Denim was traditionally colored blue with indigo dye to make blue “jeans,” though “jean” then denoted a different, lighter cotton textile; the contemporary use of jean comes from the French word for Genoa, Italy (Gênes), from which the first denim trousers were made. A similarly woven traditional American cotton textile is the diagonal warp-striped hickory cloth that was once associated with railroad men’s overalls, in which blue or black contrasting with un-dyed white threads form the woven pattern. Hickory cloth was characterized as being as rugged as hickory wood—not to mention the fact that it was deemed to be worn mainly by “hicks”— although neither may be the origin of that term [from a nickname for “Richard”]. Records of a group of New Yorkers headed for the California gold fields in 1849 show that they took along four “hickory shirts” apiece. Hickory cloth would later furnish the material for some “fatigue” pantaloons and shirts in the American Civil War.
The classical denim is a heavy fabric made from 100% cotton and woven from coarse indigo dyed warp and grey un-dyed weft yarn. The traditional denim is hard-wearing, high density fabrics with a high mass per unit area and a 3/1 or 2/1- twill weave construction. Denim is available in attractive indigo blue shades and is made for a variety of applications and in a wide range of qualities and shades. Classical denim is made from 100% cotton dyed with Indigo blue shades. Besides classic indigo blue, denim is also dyed in other fashion shades and colors, the most popular being black denim. Denim is comfortable, fashionable, affordable and durable and popular in all the age group. Denim is available in different weight ranges from 6 – 16 oz/sq yd which is categories as light denim 10-12 oz/sq yd., heavy denim 14-16 oz/sq. yd.
In order to produce good quality denim, the yarn quality used for denim production should be optimal. In rope and slasher dyeing machine the passage of yarn is very long. Hence it is necessary to control the lapping of yarn in the passage of yarn, otherwise bands of high and low densities will be formed in the yarn, which ultimately cause shade variation in the fabric. This leads huge loss of fabric. Therefore the TM of the yarn is to be appropriate to avoid any snarling of yarn during running through the passage. The yarn should be free of weak place, to avoid any breakages during dyeing. Long slub, thick and thin places in the yarn may leads to prominent fabric defects in the fabric, as denim is a contrast fabric made of indigo blue warp and grey weft yarn. The weft yarn hairiness should be low, otherwise high yarn hairiness and major variation in yarn hairiness shown weft bands which is a major fabric defects. Higher yarn neps may also cause serious fabric defects.
The quality criteria of carded OE or ring spun yarns used for denim production are as follows:
- Minimum staple length: 2.7cm
- Short fibers proportion (less than 12 mm long) should be under 40%,
- Micronaire value should be 4.0 – 4.5,
- Twist factor : 4.5 to 5.0, for warp yarns, 4.2 for filling yarn,
- Low yarn hairiness, low neppiness
- Good yarn strength and uniformity.
In the early 1990s, the majority of yarns used in denim production were OE yarns. However, recently, there is a strong demand of using more carded ring spun yarns in both warp and weft, which gives the fabric a softer handle. Warp yarns for bottom weight jeans typically range from Ne 4.0 to Ne 12.5/1 or as per requirement of finished denim fabric. Finer yarns are used for lighter weight jeans, vests, dresses, and skirts and the yarns range may be from Ne 12.5 to Ne 30.