The Geometry of Knit Fabrics Made of Staple Rayon and Nylon and Its Relationship to Shrinkage in Laundering

Abstract

The geometry of six plain, six rib, and three interlock circular knit fabrics made of staple fibers of viscose, acetate-viscose, and nylon has been studied. Data on both gray and finished fabrics for stitch length, diameter of yarn, and wale and course spacings were used in evaluating the equations derived by Peirce for length of yarn in one stitch and for weight per unit area. Measured stitch length ranged from l = 2 p + w + 4.18d to l = 2 p + w + 6.74d, as compared to the theoretical value of l = 2 p + w + 5.94d which Peirce derived. Weight of the fabrics calculated by Peirce's equation showed good agreement with that obtained by weighing a known area. In laundering tests, it was found that the various yarns shrank or stretched less than 3% in the finished fabrics. The data of wale and course spacings of both the laundered gray and laundered finished fabrics followed parabolic curves. Curves relating the wale and course spacings of the unlaundered materials conformed to no orderly pattern. Those unlaundered materials in which wale and course spacings approximated the parabolic relationship of the laundered fabrics changed the least in the length and width dimensions. Shrinkage in area increased with knitting stiffness for all of the gray fabrics and for the finished viscose; but, for the finished acetate-viscose and nylon, shrinkage in area usually decreased as the knitting stiffness increased.