Effects of Adding Sodium Acetate on Dyeing Linen Fabrics with Persimmon Tannin

Abstract

It takes 3 years to make the astringent juice of persimmons that contain mainly persimmon tannin for use in dyeing. Fabrics dyed with the juice deepen with time, and a large amount of energy is expended to more rapidly obtain deeply colored fabrics by artificial means, for example, by heating. A speedy method for extracting persimmon tannin from persimmons has recently been developed. We used this persimmon tannin in this study to make dying easier, and examined the effect of sodium acetate as an agent to promote the adhesion of the tannin to fabrics. The absorption spectrum of the dyeing bath containing persimmon tannin showed a broad peak at 450nm; however, this peak disappeared and the absorption at around 500nm increased when sodium acetate was added. This effect was also apparent in the K/S spectrum of fabrics dyed by persimmon tannin in the absence or presence of sodium acetate. In addition, higher K/S values for the dyed fabrics were shown, and the L* values in the CIE L* a* b* system were lower than those without sodium acetate. The results show that sodium acetate had a promoting effect on the adhesion of the tannin to the fabrics. This effect was greater than that at room temperature when the persimmon tannin dyeing bath was prepared with boiled water and dyeing was carried out at 70°C.