Combination Dyeing of Juniperus Chinensis Heartwood and Alnus Japonica Heartwood Extracts

Abstract

The purpose of this study was to examine improvements in dye uptake, expression of various colors, and color fastness when washed or exposed to light. We examined these improvements by doing the combination dyeing of Juniperus chinensis heartwood and Alnus japonica heartwood extracts. In this study, two combination dyeing methods were used. One-bath dyeing involves combining Juniperus chinensis heartwood extract and Alnus japonica heartwood extract. Two-bath dyeing involves dyeing by sequence, which means that we dyed the Juniperus chinensis heartwood extract first and then dyed Alnus japonica heartwood extract sequentially (or in the opposite order). In terms of improving dye uptake, two-bath dyeing was more effective than one-bath dyeing. For cotton, dyeing Juniperus chinensis heartwood extract first and then dyeing Alnus japonica heartwood extract sequentially showed higher dye uptake in the two-bath method, while for silk, there wasn't much difference in the dyeing order. Through combination dyeing, red-violet color from Juniperus chinensis heartwood and brown color from Alnus japonica heartwood made various Y, YR, R series of color as a result. Moreover, combination dyeing improved fabric's fastness when washed or exposed to light. In the case of cotton, fabric dyed using two-bath dyeing, with Juniperus chinensis heartwood extract being the first dye, showed improvement in fastness to washing and light. And in the case of silk, fastness to washing and light improved regardless of dyeing order in two-bath dyeing.