SKIN-CORE STRUCTURE OF NYLON AND “TETORON” FIBERS

Abstract

A new technique for the differential staining of the skin-core structure of nylon yarn cross-sections is described. The technique is different from the method recently developed by W. R. Berry in that a single metal-complex dye, Lanasyn Grey BL (Sandoz), is used instead of a combination of two dyes, Kiton Pure Blue V, an acid dye, and Methyl Violet 2B Supra I, a basic dye. According to the staining and differentiation procedures applied one can obtain either the skin staining or the core staining in a highly reproducible manner.
It is evident that a distinct skin-core structure is present in nylon filament, both undrawn and drawn, and that the outer skin portion always permits the dye to enter and leave much more readily than the inner core portion.
A similar structure can also be revealed in “Tetoron” polyester fiber cross-sections. Disperse dyes were used to stain slide preparations with or without carrier, followed by washing with trichlorethylene. It was, however, difficult to get a sufficiently deep staining of the cross-sections, in particular of drawn yarns.