2012 Volume 53 Issue 9 Pages 723-730
Controlling knit fabrics under high moisture conditions is known as one of the methods for preventing yarn breakage due to needle penetration during machine sewing. In this study we considered the relation between the fiber materials and the water content of knit fabrics from the point of prevention of sewing damage.
In the experiment we focused on cellulosic fibers such as cotton and modal as textile materials. The ratio of yarn breakage to needle penetration was observed from the stitched seam of knit fabrics controlled with different moisture levels.
In dry conditions it was ascertained that not a few yarn breakage due to needle penetration was caused in cotton knit fabrics and the preventive effect was obtained by controlling the moisture level of cotton knit fabrics. This result agreed with the papers reported already. On the other hand, though the yarn breakage in modal knit fabrics was negligible in dry conditions, the ratio of yarn breakage to needle penetration was increased by the increase of the water(moisture) content. The tendency observed in modal knit fabrics was opposite with the case of cotton knit fabrics. In mixture knit fabrics (50% cotton and 50% modal) ,the level of yarn breakage in the knit fabrics was situated between the levels of cotton and modal fabrics and the effect preventing yarn breakage with water content was observed.
To consider the reason why the tendency between cotton and modal fabrics was differrent, we observed the changes in the appearance of kitting yarn, and measured the raveling force from a knit fabric, the shear and bending rigidities of the knit fabric by KES System, and the tensile and edge strengths of knitting yarn. The tendency difference in the yarn breakage during sewing between cotton and modal fabrics with the water content, was caused by the decrease in the movability of yarn in modal fabrics due to swelling with water, and the large decrease in the edge strength of modal yarn.
The result of this study shows that to wet knit fabrics in same rule is not always appropriate as a countermeasure for preventing yarn breakage and it is necessary to investigate the characteristics of fiber materials of knit fabrics in various moisture conditions.
