EFFECTS OF THE TWIST OF YARNS ON THE COMPRESSIBILITY OF FABRICS

Abstract

In the previous reports^{1, 2)}, the difference between the respective compressibilities of a twistless yarn fabric and a conventional twisted yarn fabric was reported. It is made clear that, whereas the compressibility of the conventional twisted yarn fabric is little influenced by the fabric density, that of the twistless yarn fabric is much influenced by the fabric density. The present report has it as an object to make more definitely the effect of the twist of the yarn on the compressibility of the fabric. Five kinds of yarns different in the twist constant were spun and fabrics were woven of the respective yarns. The followings are made clear from the compressive force-strain curves of the respective fabrics and analyses of the deforming behaviors of the yarns in the fabrics. The compressive force-strain curve of the fabric is represented by the following equation: where P is a compressive force in g/cm², 1-h/h_0.5 is a strain, B is a constant of 0.5g/cm², and β is a compression characteristic value.
Here, the factor β is called a compression characteristic value showing the degree of the compressibility of the fabric. That is to say, the fabric low in the value of β means a fabric easy to be compressed and high in the softness. This β is very much correlated with the yarn packing factor (1-ε0) in the initial fabric. (1-ε0) can be represented also as a function of the yarn twist constant (T) and fabric density (N_c.p ). From these relations, the compression characteristic value β and compressive force-strain curve can be determined by calculation and further coincidence of the calculated value and experimental value is recognized. In the stage of weaving and designing the fabric, β can be calculated and the softness of the fabric can be known in advance.