• Journal of the Korean Society of Clothing and Textiles
• /
• v.43 no.5
• /
• pp.753-767
• /
• 2019

Dyeing behavior of indigo leaf powder was examined in regards to the effect of the amount of pigments on color and dye adsorption for silk dyed by reduction and nonreduction dyeing. The amount of indigotin and indirubin pigments adsorbed in dyed silk was examined by HPLC-DAD analysis. The color of dyed silk showed 7.7BG - 2.7B hue when silk was dyed at $50^{\circ}C$, and 3.5G - 4.9BG when dyed at $70^{\circ}C$. Blue ($b^*$) and green ($a^*$) color decreased as the pH of dyebath increased. When silk was dyed using nonreduction, R (red) and RP (red purple) hue and R hue was more apparent in samples dyed at $90^{\circ}C$. In reduction dyeing, amount of indigotin detected from silk exceeded the amount that was initially contained in the input dye. The amount of indirubin was lower than indirubin that was initially in the powder. In nonreduction dyeing, silk showed a higher amount of indirubin adsorption compared to silk dyed by reduction. The amount of indigotin adsorbed in silk was lower than the amount initially contained in the input dye. The amount of indigotin and indirubin adsorption was primarily dependent upon the dyeing method-reduction or nonreduction along with dyeing temperature and the pH of dyebath.

• The Research Journal of the Costume Culture
• /
• v.23 no.5
• /
• pp.768-777
• /
• 2015

In this study, the dyeing of silk fabric with Polygonum cuspidatum extracts was investigated. The contents of this study are as follows. First, the proper dyeing conditions were investigated by measuring the dye uptake (K/S value) that depended on the dyeing conditions when silk fabric was dyed with Polygonum cuspidatum extract. Second, the brightness (L), hue, and chroma differences that appear after mordanting with Al, Cu and Fe were investigated by measuring the CIELAB and Munsell values. And third, the colorfastness and antibacterial property were measured. When the silk fabric was dyed with Polygonum cuspidatum extract, the proper dyeing conditions were a colorant concentration of 90% v/v, a dyeing of time 100 minutes, a dyeing temperature of $70^{\circ}C$, and a dyeing of pH 3. In mordanting methods, the dyeabilities of post-mordanting were higher than those of premordanting. The hue value displayed yellow (Y) and yellow-red (YR) in cases of pre and post mordanting. The C value decreased by the mordanting of Polygonum cuspidatum extracts. Generally the colorfastness of mordanted fabrics was improved by mordanting. The dyed fabrics showed a 90.6% of Staphylococcus aureus reduction rate, and the dyed and mordanted fabrics showed 97.1% bacteria reduction rate. The dyed and mordanted fabrics showed above 90.5% Klebsiella pneumoniae reduction rate, and Cu mordant revealed the most effective bacterial reduction.

• Textile Coloration and Finishing
• /
• v.33 no.4
• /
• pp.191-201
• /
• 2021

In this study, an eco-friendly indigo reduction system(scale up reduction, use of buffer solution, and pH control) using baker's yeast(Saccharomyces cerevisiae) was applied for natural indigo(Polygonum tinctorium) dyeing of Hanji fabric and Hanji-mixture fabric(Hanji/Cotton, Hanji/Silk). The effect of concentration of baker's yeast, repeat dyeing, and bath reuse was investigated in terms of dye uptake indicating reduction power. And the oxidation-reduction potential(ORP) was monitored. We also evaluated color properties and colorfastness according to the color strength. The yeast concentration did not significantly affect the maximum reduction power. However, the highest yeast concentration was effective in improving the initial dye uptake, and its the reduction retention power was the most excellent. Even on the last reduction day, the effect of increasing the dye uptake by repeat dyeing was observed. And it was confirmed that the reduction bath could be reused for up to 30 days by supplementing yeast at the end of reduction. For all the fabrics used, deeper and darker PB color were obtained by repeat dyeing. As dyeing was repeated, purplish tint got stronger on the Hanji/Silk fabric compared to other fabrics. Regardless of the composition of Hanji fabrics and color strength, washing and dry cleaning fastness were relatively good with above rating 4-5, and fastness to rubbing and light were acceptable with a rating 3-4 ~ 4-5. The eco-friendly natural indigo dyeing process using niram and baker's yeast would offer global marketability and diversity of Hanji product as a sustainable high value-added material.

• Textile Coloration and Finishing
• /
• v.21 no.6
• /
• pp.12-21
• /
• 2009

The dyeing property of direct-spinning type and seaisland type 0.2D micro polyester nonwoven fabrics was characterized by three disperse dyes (Dorosperse Red KFFB, Blue KGBR, Yellow KRL) at $120^{\circ}C$ and $130^{\circ}C$. Before and after reduction cleaning, dyeing fastness was evaluated and the thermomigaration after heat setting at $180^{\circ}C$ for 60 min were also evaluated. Direct-spinning type fabric showed better dyeing property, wash fastness, and light fastness, but worse rub fastness than seaisland type fabric. The dyeing property and fastness of direct-spinning type fabric increased at higher dyeing temperature, whereas seaisland type fabric exhibited lower dyeing fastness and the increase of thermomigration at higher dyeing temperature. Non-fixed dye in fiber surface was removed by reduction cleaning process, then dyeing fastness was improved and thermomigration decreased. The higher dye uptake of direct-spinning type non-woven fabric caused the increase of dye molecule migration from fiber internal to fiber surface, so this fabric showed larger thermomigration than seaisland type non-woven fabric.

• Textile Coloration and Finishing
• /
• v.22 no.2
• /
• pp.101-109
• /
• 2010

The objective of this study is to investigate the characteristics of natural indigo dyeing of cotton fabric. Reduction and dyeing were carried out by one-step process using an infrared dyeing machine at the liquor ratio of 1:100, and subsequently oxidation and washing in water were followed. Dye uptake was increased with the increase of indigo concentration. Over the full range of dyeing tests, the dyeing condition was optimized to $40^{\circ}C$ for 40min. For most of dye concentrations, the cotton fabrics showed mainly PB color. Maximum K/S value was shown at 4g/L of sodium hydrosulfite concentration and the color strength increased with the increase of dye concentration. Value(lightness) decreased with the increase of dye uptake irrespective of mercerization or reduction method, while the mercerized cotton showed two times higher dye uptake than the untreated cotton. Whereas hue of the untreated cotton showed large decrease of P character(5.6~3.5 PB) with the increase of dye uptake, that of the mercerized cotton increased P character(4.7~5.5 PB). Irrespective of mercerization, value and chroma decreased with the increased of dye uptake. In addition, the untreated showed lower chroma than the mercerized cotton. In the case of traditional reduction, hue of the untreated cotton was changed very little with the increase of dye uptake. For hydrosulfite reduction, P character decreased with the increase of dye uptake. The difference of hue value was small with the change of reduction method(hydrosulfite reduction or traditional fermentation). Color character was not influenced by the changed maximum absorption wavelength. Washing fastness showed 4~4/5 shade change rating without any staining. And dry rubbing fastness was good at low color strength. The bacterial reduction ratios of dyed cotton fabric were also increased.

• Fashion & Textile Research Journal
• /
• v.4 no.6
• /
• pp.550-556
• /
• 2002

The changes of the main body temperature of a I tube 2 chamber bent silkworm type dyeing machine and the reduction of energy consumption of the dyeing machine by the energy saving design are reported. This dyeing machine was developed for the purpose of the energy saving and high efficiency. In this study, the changes of the main body temperature of the 1 tube 2 chamber bent silkworm type dyeing machine were studied experimentally. Especially the effect of the blower motor electric current and the main body pressure at various blower frequencies were studied experimentally. In the experimental data for the changes of main body temperature, it was shown that the main body temperature increased as the blower motor electric current and the main body pressure increased.

• Journal of the Korean Professional Engineers Association
• /
• v.15 no.2
• /
• pp.24-31
• /
• 1982

This study concerns with the reduction of the COD and deceleration of dyeing wastewater from DAEGU city area by ozonation. The COD reduction by ozonation follows near linear relationships versus ozonation time, temperature and concentration. The color in dyeing wastewater and of dyes can he strikingly reduced as the water is quasi colorless after ozone treatment. COD reduction rate of wastewater was found not to be dependented on pH, however, high temperature gave better results, although economically not feasible. The ozonation of dyeing wastewater can give good results when dyes, scouring agent and sticking agents were pre-separated.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.42 no.2
• /
• pp.342-359
• /
• 2018

This research investigated the relationship between the amount of fixed pigment and the color of silk dyed with three types of fermented indigo powder dye under different temperatures and pH, by reduction or nonreduction method. Amount of fixed pigment was analyzed using the Ultimate 3000 HPLC-DAD instrument and the color of dyed silk was measured using the X-rite spectrocolorimeter. All silk samples dyed by reduction method showed PB color. The amount of indigotin fixation was dependent on the dyeing temperature and pH regardless of the indigotin composition in the dye. Indirubin was less dependent upon the dyeing condition in the reduction dyeing and its fixation was minimum level. Dyeing conditions which can maximize the indigotin fixation were $50^{\circ}C/pH$ 11 and $70^{\circ}C/pH$ 7 conditions in reduction dyeing. Color of silk showed more redness ($a^*$) thus higher PB color when the indigotin fixation was low and indirubin fixation was relatively high. Indirubin fixation was very low with slightly better fixation by nonreduction method. More reddish color was obtained by nonreduction dyeing, and by more alkaline dyebath.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.34 no.3
• /
• pp.508-517
• /
• 2010

One-step reduction/dyeing method was optimized for wool dyeing with natural indigo dye in this study. The effects of reduction/dyeing conditions including dye temperature and time, the pH of bath, concentration of dye, and reducing agent on dye uptake and color were investigated. The dye uptake was higher with no addition of alkali. Dyeing was carried out through the use of only sodium hydrosulfite in the bath. The maximum dye uptake was obtained at $60^{\circ}C$ for 30min and the dyed fabrics appeared in the PB Munsell color range. Dye uptake improved with the increase of a natural indigo dye concentration with the same sodium hydrosulfite concentration. At a higher dye uptake, the fabric color became more purplish and the maximum absorption shifted from 660nm to 620nm. Color reproducibility was reliable with a color difference in the range of 0.41~1.43. Regardless of color strength, washing and dry cleaning fastnesses were good with a 4/5 rating, and fastnesses to rubbing and light were acceptable with a 3/4~4 rating.

• Textile Coloration and Finishing
• /
• v.15 no.6
• /
• pp.1-7
• /
• 2003

Polyester microfiber has usually greater dye uptake than normal denier polyester fiber in same dyeing condition. In spite of this high dye uptake dyed microfiber fabric has not only low visual colour depth but also poor washing fastness property. In order to study high colouring dyeing technology and high washing fastness of polyester microfiber, dyeing property of polyester microfiber was investigated according to the dye solubility and particle size of used disperse dyes in aqueous dye solution. After disperse dyeing, dyed fabric with disperse dye was redyed with a vat dye without reduction clearing in order to obtain a high washing fastness property. The result were as followings ; A small particle sized disperse dyes such as C. I. Disperse Blue 56 and Red 60 showed high rate of initial exhaution compared with a large particle sized disperse dyes like C. I. Disperse Blue 165 and Red 343. In study of dyeing property of polyester microfiber with C. I. Vat Blue 1, polyester microfiber could achieve high dye uptake at a given optimum vatting process conditions. On the other hand, in consecutive dyeing with disperse and vat dye, K/S value of polyester microfiber with a small particle sized disperse dye increased without reduction clearings, but K/S value of polyester microfiber with a large particle sized disperse dye decreased with reduction clearings.