A Study on the Relation between Hairiness Index of Uster Tester 3 and Hairiness Values of Uster-Zweigle Hl 400 Tester

The term “hairiness”, is used to express the fibres which protrude from staple or spun yarn body and is an inherent characteristic of staple fibre yarn. Two widely used hairiness measuring instruments are -Uster tester 3 and Uster –Zweigle HL 400. The principles of measuring hairiness are far apart from each other in these instruments. The first one measures the hairiness value as hairiness index (H), which is defined as the total length of all fibre ends sticking out in cm, related to a yarn section of 1cm in length where as the second one measures the number of protruding fibres from yarn surface at different length zone per 100 meter which is an absolute non cumulative value. Jute yarn samples are prepared to correlate the hairiness values obtained from these two instruments by varying the linear density and the twist factor of the jute yarn tested parallely. Regression equations and corresponding correlation coefficient values for number of hairs at different specified distance from yarn body and hairiness index for set of jute yarns having different yarn linear density at a constant twist multiplier and different twist multiplier at a constant linear density are calculated. Maximum correlation between yarn hairiness index and hairiness value of Uster –Zweigle HL 400 is obtained form number of hairs present between 3 and 4 mm distance from yarn body. Finally when all samples are considered simultaneously, a very good correlation coefficient is obtained from the regression equation. Since Uster Zweigle HL 400 is a newly developed instrument, this equation helps to predict the number of hairs of length between 3mm/100m from the hairiness index value obtained from the commonly used hairiness meter attached with Uster tester 3.