長繊維漁網糸の摩擦に対する強さ-I

Abstract

Among various physical properties of fishing net twines, wear resistance seems to be affected by the number of twists given to yarn, strand and twine. In the present study the sample twines used were the same in quality (vinyle chloride synthetics, Teviron, 300 deniers ZN1×SN2×ZN3) and in number of yarns of which they consisted. But they differed one another in number of twists given to yarn, strand and cord as shown in Table 1. When the breaking strength of a material rubbed n times with an apparatus (Fig. 1) is represented by Tn, and that of a non-rubbed material by To, one may denote the wear resistance as Tn/To for comparing it among the differently twisted samples. The results obtained are summarized as follows. 1) There is much difference in the wear resistance (Tn/To) even in the same quality of the synthetic twines (Fig. 2 and Table 1). 2) It has been recongnized that the difference in the wear resistance among these twines tested is concerned with the number of the second twists (N2) of the twines (Table 2). 3) Neither the weight nor the diameter of the twines seems to affect the wear resistance. 4) There are marked differences in rigidity closely related the 2 nd twist (N2) but hardly with the 1 st and the 3 rd twists (N1, N3) (Fig. 3). See the foot note under Table 1 concerning for N1, N2 and N3. 5) Relationship between coefficient of the friction and either the rigidity or the wear resistance had an inclination inverse from each other: the smaller the coefficient of friction, the greater is the rigidity as well as the wear resistance (Figs. 5 and 6). 6) On the other hand, a high correlation has been noticed between the wear resistance and rigidity of the tested twines (Fig. 4). 7) It is inferable that the differences in the wear resistance are primarily attributed to the number of twists, and in the present case, 2 nd twists, as the twists govern the rigidity which in turn affects coefficient of friction. 8) It is doubtful, however, whether or not the number of 2 nd twists is the only factor that always increases the rigidity and decreases the coefficient.