• Textile Coloration and Finishing
• /
• v.24 no.1
• /
• pp.18-26
• /
• 2012

In this work, colorants extraction process from gromwell was studied for making powder form of colorants by solving the high viscosity problem of gromwell extracts. In order to do that, sugar extracted together with colorants must be pre-extracted. For sugar decomposition, gromwell roots were pretreated with various enzyme solutions. The total sugar content of pre-extract with enzyme solution was measured. Accordingly, the effects of enzyme type and pretreatment condition on sugar decomposition were investigated to find appropriate enzyme(amylase, hemicellulase, pectinase) and enzyme activity (100~1000unit), pre-extracted time(3~24hr). Color characteristics and dye uptake of dyed fabrics were evaluated. Gromwell colorants were assessed for their potential antimicrobial activities, which possibly expand their end use as functional pigments. The efficiency of removing sugar was increased in the order of hemicellulase, pectinase, amylase, $H_2O$. Gromwell colorants powder yield was in the range of 4.4% to 9.8% depending on pretreatment enzyme. Gromwell colorants produced RP color on the silk and wool fabrics with good dye uptake. Antimicrobial activity of gromwell colorants will greatly increase its potentiality for applying as functional natural colorants in the future.

• Textile Coloration and Finishing
• /
• v.21 no.4
• /
• pp.23-32
• /
• 2009

The objective of this study is to investigate the efficacy of leaf powder colorants as substitutes for traditional indigo dyeing. Leaf powder colorants were prepared by hot air($50^{\circ}C$) and room temperanrre($25^{\circ}C$) drying methods from fresh leaves. The presence of indigo in the leaf powder colorants was confirmed by UV/Visible absorption spectra. All the powder colorants showed broad absorption at 602 nm as same as synthetic indigo. Dyeing was done by reduction method with sodium hydrosulfite and sodium hydroxide. Leaf powder colorants produced blue color on silk fabrics, showing similar color to the one dyed traditionally with fresh juice extract. The powder colorants prepared at room temperature drying were more stable for long term storage than that prepared by hot air drying. Thus, the powder colorants prepared by room temperature drying was reduced and dyed in one-step process without sodium hydroxide in the dyebath for further investigate dyeing properties. K/S value of the fabric dyed without sodium hydroxide was much higher than one dyed with sodium hydroxide. Regardless of the addition of sodium hydroxide, rubbing fastness was fairly good showing above 4 rating. Fastness to dry cleaning and light of the fabrics dyed without sodium hydroxide were mote higher than that dyed in alkaline condition.

• Textile Coloration and Finishing
• /
• v.21 no.1
• /
• pp.10-20
• /
• 2009

The objective of this study is to investigate the efficacy of leaf powder colorants as substitutes for traditional fresh juice extract dyeing. Three kinds of leaf powder colorants were prepared by freeze drying method with or without deep freezing as pre-treatment: one powder colorant from fresh leaf juice with deep freezing; two kinds of powder colorant from fresh leaves with and without deep freezing. Their dyeing properties and storage stabilities were studied and compared with the traditional fresh juice extract dyeing. The presence of indigo in the powder colorants was confirmed by UV/Visible absorption spectra. They showed absorption peak at 602nm which was same with indigo absorption peak. Dyeing was done at low temperature around 6$^{\circ}C$. All three powder colorants produced B colors on silk fabrics, showing similar color to the one dyed traditionally with fresh juice extract. The powder colorants from leaves gave higher color strength than the powder from leaf juice. The powder colorant prepared from leaves with deep freezing was the most stable for long term storage as its color and color strength were not changed after 360 days. So, this was used for further dyeing to study the effects of concentration and repeat dyeing on color strength and colorfastness. Fastnesses to dry cleaning and rubbing were fairly good above 4 rating. Further study is needed to improve light fastness. It was concluded that the leaf powder colorant with deep freezing could be used as a substitute for traditional juice extract dyeing at all seasons.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.3
• /
• pp.549-552
• /
• 2004

A simple, efficient and accurate method was developed for the simultaneous determination of non-permitted oil soluble colorants (sudan I, II, III and IV) in foods. The identification has been carried out for sudan colorants by TLC as well as HPLC with photodiode array (PDA) detection. Separation of sudan colorants was achieved within 20 min by a gradient elution with water and acetonitrile as eluents. Sudan colorants showed good linear relationships in the range of 0.1 ～ 100 $\mu\textrm{g}$/mL. The correlation coefficients of the calibration curve for sudan colorants exceeded 0.999. The detection limits (signal-to-noise ratio 3 : 1) for sudan I, II, III and IV were 0.01, 0.01, 0.02 and 0.02 $\mu\textrm{g}$/mL, respectively. This method has been successfully applied to the analysis of red pepper powder, Kimchi and Kakdugi, and the average recoveries for real samples ranged from 83.02% to 104.3%.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.32 no.6
• /
• pp.928-934
• /
• 2008

The objective of this study is to investigate the dyeing properties of safflower yellow dye on silk for the standardization of dyeing process and color reproducibility. Yellow colorants were water-extracted from safflower petals, concentrated, and freeze-dried to obtain colorants powder. The effects of dye concentration, dyeing temperature, and pH of dye bath were studied in terms of dye uptake and shade. Fastness to dry cleaning and light was evaluated. Dye uptake increased with raising temperature and brighter and more vivid yellow shade was obtained when dyed at $30^{\circ}C$. As colorants concentration increased, dye uptake increased progressively and the shade got darker and deeper. Maximum color strength was obtained at pH 3.5. It was speculated that the adsorption of colorants seemed to occur mainly by hydrogen bonding and physical force at pH 5.5 and by ionic bonding as well as hydrogen bonding below isoelectric point(pH 3.8-4.0). The results of reproducibility test showed acceptable color difference in the range of $1.11{\sim}2.01$. Washing fastness was fairly good as 4/5 rating, while light fastness was 2/3 rating.

• Textile Coloration and Finishing
• /
• v.10 no.3
• /
• pp.20-28
• /
• 1998

Natural indigo colorants were prepared by extraction of polygonum tintorium which was harvested just in the blooming season(in the late of July). The components were analyzed by TLC and HPLC, and its structures were analyzed by FT-IR, EI-mass and NMR. The dyeing mechanism and fermentation conditions were investigated. Its colour fastness was studied as well. The results obtained are summarized as follows ; The natural indigo powder was dissolved in DMSO and developed in eluent, $CHCl_3/CH_3CN(8.5:1.5v/v)$ by means of TLC for its quality analysis. It was segregated into indirubin as il red colour and indigo as a blue colour. In case of HPLC analysis, the retention times of indirubin and indigo were 7.442 and 6.543, respectively. FT-IR spectrum of indirubin showed a peak for NH residue between 3200 and $3300cm^{-1}.^1H-NMR$ spectrum for indigo displayed AA'BB' spin system caused by indole structure between 6.5 and 7.7ppm of H4, 5, 6 and 7, and -NH proton for indirubin showed an singlet between 10.88 and. 11.0ppm. EI-mass spectrum of indigo an d indirubin both disclosed their molecular size as 262 and it implies that these two substances are isomer.

• Journal of the Korean Home Economics Association
• /
• v.38 no.9
• /
• pp.119-130
• /
• 2000

The purpose of this study was to confirm the possibility of screen printing with Natural dyes. The coloring matter such as sappan wood was used in order to obtain the colorant powder through the processes of extraction, low pressure concentration and the spray dry. After the screen printing on silk and cotton fabrics with colorant, K/S value changes of color and color fastness were measured. The main resets were as follows : 1. The viscosity of printing thickeners of sappan wood powder was about 15,200 cps, and the highest K/S value of the fabrics printed with sappan wood was obtained at 90$\pm$2$\^{C}$ of steaming temperature and 80 minutes of steaming time. 2. For the fabrics printed with sampan wood, adding of urea was not effective, since the more the concentration of urea increased, the more K/S values decreased. 3. For the natural dyes printing, the more the concentration of colorants increased, the more K/S values increased. In general, the K/S values of the printed fabrics were higher when treated with mordants rather than without mordants. Specifically, the λmax sappan wood was 520∼570 nm, and the K/S value was highest when treated with Cu mordant and lowest when treated with Sn. 4. Generally, the color fastness was relatively fair.

• Textile Coloration and Finishing
• /
• v.22 no.1
• /
• pp.71-76
• /
• 2010

In this study the optimum dyeing conditions and blocking effect of UV deodorization efficiency of Ligustrum japonicum Thunb were investigated. Colorants were water-extracted from Ligustrum japonicum Thunb fruit and freeze-drided to obtain colorants powder. The effects of dye concentration, dyeing temperature, dyeing time, and the number of dipping count were studied. Fastness to dry cleaning, rubbing, perspiration, and light were measured according to KS K 0644, KS K 0650, KS K 0715 and KS K 0700, respectively. In order to examine the dyeability according to dyeing conditions, reflectance of fabrics were measured by using UV/VIS spectrophotometer. The bath ratio was 1:20. Dyeing concentration was 100, 200, 300, 400 and 500% on the weight of fiber. Dyeing time was 20, 40, 60, and 80 minutes. Dyeing temperature was 20, 40, 60, 80, and $100^{\circ}C$. The infrared high pressure dying machine was used. As dyeing concentration increased, dye adsorption increased up to 400% and it slowed down. Dye uptake was increased with raising themperature up to $80^{\circ}C$ and it slowed down. Dye adsorption occurred rapidly at first 20 minutes and then it slowed down and reached almost maximum dye uptake at 60 min. Dye uptake increased by repeated dyeing. Therefore, it is considered that optimum dyeing condition is 400%(o.w.f.), $80^{\circ}C$, 60 min. And repeated dyeing improves dye uptake. Color fastness to dry cleaning and rubbing was good, but light fastness and perspiration fastness was not good. Blocking effect of ultraviolet radiation and deodorization efficiency was good.

• Textile Coloration and Finishing
• /
• v.14 no.4
• /
• pp.229-239
• /
• 2002

Colorants were extracted from the heartwood of sappan lin. with MeOH under reflux, and the concentrate or the powder of dye was prepared by low pressure concentration method using suitable organic solvent. Various components were isolated from sappan wood, and the chemical structure and mechanism of compound having the excellent antibacterial and deodorization properties were analyzed. The results obtained are as follows ; The seventeen components of sappan wood were seperated by HPLC chromatography, and the five components among them were existed more than 6% and the other components were existed lower than 0.6%. The resolving powers of the non-polar solvent and polar solvent systems were evaluated by their ability to resolve the samples. It showed that chloroform-methanol-water(800:150:10) system has the best resolving power. Although the seperation rate is very slow, polyamide C-100 column chromatography gives a clear seperation of sappan wood. On the basis of the spectrometric data such as IR, UV, $GC-Mass,\;^1H-NMR,\;^{13}C-NMR\;and\;^1H-^{ 13}C-NMR$, the chemical structure of compound haying the excellent antibacterial and deodorization properties was established as brazilin containing the functional groups such as two quaternary carbon, one benzyl carbon, methylene contiguous to oxygen and methylene caused by oxygen atom.

• Journal of Sericultural and Entomological Science
• /
• v.40 no.1
• /
• pp.78-85
• /
• 1998

Colorants were prepared by extraction of natural indigo which was harvested just in the blooming season(in the late of July). 100 g of fresh leaves soaking in 1 ιwater was kept at 3$0^{\circ}C$, 30 hours. A solution of 3g/l calcium hydroxide was added into it to precipitate dye substance and it was freezing-dried into powder form. The fermentation and dyeing conditions were investigated. The results obtained are summarized as follows; K/S value of dyed silk fabrics of fermentation conditions was higher at 95$^{\circ}C$ for 20 min. than at 4$0^{\circ}C$ for 20 hours. Furthermore, K/S value of dyed silk fabric was raised by the addition of 5g/l of glucose and 5g/l of NaOH. K/S value of dyed silk fabric was raised by the addition of 5g/l of glucose and 5g/l of NaOH. K/S value increased as extending of dyeing time when dyed till 2 hours at 3$0^{\circ}C$. K/S value decreased in order of 3$0^{\circ}C$, 4$0^{\circ}C$ and 5$0^{\circ}C$, at the various dyeing temperatures and dyeing concentrations, and colour fastness ranged from 4 to 5 grade in terms of washing, perspiration and light fastness.