Effects of Tｒace Metals in Wool Fibers on the Dyeing with Carminic Acid

Abstract

Thus far, we have found the color difference between silk and wool fabrics dyed with hematein in spite that both fabrics are protein. This finding motivated us to investigate the function of trace metal ions in the cell membrane complex (CMC) wool fiber that play important role in the dyeing of wool fabrics [1-2]. In this paper, we clarify the effects of the trace metal ions in the CMC and identify the metal ions that affected the color of dyed wool fabrics. This is done, by examining the effect of metal ions in wool fabrics dyed with carminic acid; on the K/S--wavelength (λ) curves of the surface color of dyed wool fabrics and pre-treated wool fabrics, i.e., cortex cells, and wool fabrics modified using formic acid and ethylenediaminetetraacetic acid (EDTA). Consequently, effects of trace metal ions was discernible from the wavelength shift of K/S-λ curves between wool fabrics treated using EDTA and untreated wool fabrics. Then, silk fabrics pre-mordanted with copper (Cu), zinc (Zn) and iron (Fe) have treated with a buffer in the pH range of 3-9 after dyeing, and K/S-λ curves of dyed three-metal mordant silk fabrics was compared with that of dyed wool fabrics. The K/S-λ curves of wool fabrics were comparable to those of zinc-mordanted silk fabrics among all three metal ions studied. Therefore, we concluded that the trace metal ion that affects the surface color of wool fabrics dyed with carminic acid is zinc.