What is Yarn Hairiness?
Yarn hairiness is defined as hairs protruding from the main body of a yarn. It is the ratio of length of all protruding fiber in 1 cm and the yarn actual length (1 cm). Yarn hairiness is an undesirable property which causes problems in fabric production. It is a unit less parameters. Yarn hairiness, one of the most important yarn parameters, is usually characterized by the amount (number or cumulative length) of fibers protruding out of the compact yarn body. Therefore it is very important to measure the length of hair in order to control it. However, at the same time it is not possible to represent hairiness with a single parameter because the length of hair and number of hairs exceeding 3 mm length as a percentage of the total number of hairs is found to be linearly related to the linear density of yarn. Hairiness value of the coarser yarns is normally lower than the finer yarn due to good cohesive / frictional forces between the constituent fibers in the coarser yarns. Hairiness could broadly be classified under three categories, namely leading hairs, trailing hairs and looped hairs. Yarn hairiness has a great influence on the sizing, weaving and knitting processes. Higher hairiness increases the cost of sizing. During the shedding operation in weaving, the hairy yarns often entangle with each other and thus hinder the creation of distinct shed which is essential for the passage of the weft or weft carrier. In case of air-jet weaving, the yarn hairiness favorably influences the air-drag exerted on the yarns. Hairy yarns generate fly during the knitting and obstruct the smooth functioning of the machine parts, including needles. Excessive variation of yarn hairiness may cause a ‘Barre’ effect in the finished fabric. However, yarn hairiness is a necessary evil. Too much hairiness is detrimental for the fabric appearance but a certain amount of hairiness is important to both the textile operations and the appearance of fabrics and garments so that the fabric possesses a softer feel and a warmer hand.
Causes of Yarn Hairiness:
1. Raw material
2. Maturity: In case of cotton 70% maturity of the fibers is needed; if less it then leads to hairiness. Immature and dead fibers result in hairiness.
3. Micronaire (fineness): Range of micronaire value of fiber for cotton yarn is 4.2 ± 0.2. Micronaire value of 4.2 ± 0.6 results in increased hairiness, which is used in soft, flannel-like fabrics.
4. Uniformity ratio: Normally, uniformity ratio of fibers is 40%-50%. If it is less then hairiness occurs.
5. Process: Inadequate drafting and orientation – spinning triangle.
6. Maintenance: Rubbery surfaces, life of devices or machine parts.
Effects of Yarn Hairiness:
▪ It causes problems in printing.
▪ Fine designs are difficult to make.
▪ Machine parts life is reduced.
Let’s talk some Benefits of yarn hairiness.
- Benefits of Yarn Hairiness:
1. Flannel-type fabrics can be produced
2. Increasing feel softer and warmer to the touch, enhancing the comfort of fabrics
3. Slightly hairy yarn can create a natural, rustic, or matte finish in home decor or casual wear
4. The comfort parameters of textile fabrics (air permeability, moisture vapour transport and thermal properties) depend on yarn hairiness.
- Disadvantages of Yarn Hairiness:
1. Hairiness lowers the yarn strength.
2. If yarn is fuzzy, size material will not penetrate to the required amount and a greater amount will accumulate on yarn surface, that is, coating is more but penetration is less.
3. In air jet weaving, clear shed is not produced. Similarly if fabric density is more, two adjacent yarns cause problems due to hairiness.
4. The machine parts like drop wires, heald wires and reed get worn out frequently.
5. In knitting, the needles get worn out frequently.
References:
1. Physical Testing of Textiles by B. P. Saville
2. A Practical Guide to Textile Testing By K. Amutha
3. Technical Textile Yarns: Industrial and Medical Applications Edited by R. Alagirusamy and A. Das
4. Textile Engineering – An Introduction Edited by Yasir Nawab
5. Bamboo Fibers: Processing, Properties and Applications By K. Murugesh Babu and S.M. Chandrasekhara
6. Computer Technology for Textiles and Apparel Edited by Jinlian Hu