• 한국염색가공학회지
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• 제24권4호
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• pp.253-259
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• 2012

In this work, the natural indigo production process from Polygonum tinctorium was balanced based on the traditional Niram method in Korea. A standard procedure was determined considering the conditions of indican extraction from plant material, the amount of alkali for precipitation, storage of extract, etc. The effect of experimental conditions on the yield of crude dye was investigated. The contents of indigo and indirubin of the crude dyes were analyzed by HPLC. Increase of the amount of crude dye was observed within 1-2.5 days of extraction time. Longer extraction beyond 2.5 days resulted in a slight decrease in the amount of crude dye. There was no consistency in terms of indigo content depending on extraction pH. We found that the storage of extract or harvested plants affected adversely to dye yield and dye quality. Based on the lab scale extraction, large scale extraction was performed for 2-2.5 days in water and 2.0-2.5 g/L of $Ca(OH)_2$ was applied for precipitation of indigo dye. We obtained natural indigo dye containing about 15% of pure indigo in scale-up production using whole plant except root.

• 복식문화연구
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• 제19권3호
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• pp.612-621
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• 2011

The process of making or cultivating indigo dyes is very cumbersome and complex. The dye extraction and dyeing methods using general plant dye, moth repellent dye, fast acting natural dye, and other dyes are very different. This research investigates the extraction of indigo dye and liquid dye extraction of polygonum(indigo) plants using calcium oxide water. While extracting indigo dye the concentration of purified indigo dye may be controlled by adjusting the pH level. Due to the various uses of dyes the adjustment of surface color must be considered. In regard to the change according to different concentrations of reducing agents, it was found that cotton fabrics and ramie fabrics show the highest color difference at 0.4% and 0.3% respectively. As the reduction temperature increases, the color difference increases as well. The maximum color difference was found to appear at $90^{\circ}C$. Cotton fabrics and ramie fabrics showed 70.55 and 67.01 respectively. The color difference increases as the concentration of dyes increases, but at a concentration of 300%, cotton fabrics was found to show 6.22PB in H value using the Munsell color system, containing purple and blue color. The pH of the polygonum dyes extracted through this experiment were adjusted by adding calcium oxide to the experimental water, without directly adding calcium oxide to the liquid polygonum extract. In a refine state, it was mixed with polygonum extract to extract a more refine and highly concentrated indigo dye. When lye and reducing agents are added to extracted indigo dye and sealed for long-term storage, it can be effective and easily used for dyeing.

• 한국염색가공학회지
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• 제12권3호
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• pp.174-182
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• 2000

We prepared natural indigo/calcium hydroxide complex powder from tinctoria's leaf, according to the demand of developing new dyeing technique of natural fibre with natural indigo. FT- IR and UV/Visible spectra were operated to find the dyeing properties of synthetic indigo and natural indigo powder. Cotton, flax and silk fabrics were dyed with different pH, dye concentration and dyeing time. The colour yield of indigo dye was quite sensitive to dye bath pH and fabric. In synthetic indigo, the highest K/S value of dyed silk fabric was shown at near pH 9.0, and which of flax and cotton fabric were shown at pH 11.0. In other hand, in the case of natural indigo complex powder, the highest K/S value of dyed silk fabric was shown at near pH 8.0, and which of flax and cotton fabric were shown at pH 9.5∼pH 10. Mercerized cotton fabric dyed with natural indigo powder has a little antimicrobial activity.

• 한국의류학회지
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• 제34권12호
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• pp.1933-1946
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• 2010

This paper is a comparative analysis of the $19^{th}$ century practice of indigo dyes and dyeing in Korea and England. From over hundreds species of indigo plants in the world, it was dyer's knotweed and woad that were cultivated in Korea; however, the only indigo plant grown in England was woad. Indigo dye was produced in the form of damp indigo sediment (jeon) in Korea; however, imported indigo (as a main dye) and couched woad (as an additional dye) were indigo dyes used in England. There existed three kinds of indigo vats, the ice vat, ash-water vat, and indigo sediment (jeon) vat, in Korea. The fresh leaves of indigo were used for both the ice vat and ash-water vat. The ice vat was very convenient for preparation, but had a weakness in the inability to produce a very deep shade of blue. The ash-water vat and indigo sediment (jeon) vat were in use for producing a very deep shade of blue. The indigo sediment Goon) vat was employed presumably only by professional dyers. The indigo vat practiced in England was categorized into two types; one was woad-indigo vat, and the other was an indigo powder vat prepared by using imported indigo rock. There was a tendency to adopt different kinds of indigo vats according to the material to be dyed. The woad-indigo vat was employed for the dyeing of wool. A few of chemical vats with imported indigo were adopted, especially for the dyeing of cotton. Indigo dyers in 19th century Korea were differentiated from the rest of the dyers. They managed the growing of indigo plants as well as the production of indigo sediment (jeon). Woad dyers in 19th century England handled woolen cloth as well as worsted and woolen yarn in general. However, they sometimes dyed silk skein as well. They produced several colors such as black, blue, slates, grays, by using both woad and imported indigo.

• 한국의류학회지
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• 제32권12호
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• pp.1963-1970
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• 2008

전통적인 니남쪽염료 제조법을 기준으로 굴껍질가루 대신 칼슘하이드록사이드를 사용하여 천연인디고분말염료를 만들었다. 제조한 인디고분말염료에 대한 텐셀의 염색성을 몇 가지 실험조건에서 조사하였으며 염색견뢰도를 측정하였다. 제조한 인디고분말염료는 약 15.5%의 인디고 성분과 0.757%의 인디루빈 성분을 함유하는 것으로 분석되었다. 환원과 염색을 자동염색기로 one-step으로 하였으며 환원제로 소디움하이드로설파이트를 사용하였다. 최대염착량은 $60^{\circ}C$에서 얻었으며 초기 20분 동안에 염착이 거의 이루어졌다. 본 연구의 실험조건 범위에서는 염료농도 4g/L까지는 2g/L의 환원제 농도에서, 염료농도 8g/L에서는 3g/L의 환원제 농도에서 최대염착량을 보였다. 텐셀은 염욕에 가성 소다를 넣지 않고 pH 5.75에서 염색할 때 훨씬 높은 염착량을 나타냈다. 염색견뢰도는 4/5-5등급으로 대체로 우수하였으며, 염착량이 낮을수록 더 높은 광퇴색을 보였다.

• 한국의류학회지
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• 제41권2호
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• pp.212-223
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• 2017

This research investigated the screen printing method for natural indigo dye on cotton fabric. We examined four types of thickening agents (arabic gum, guar gum, indalca, and CMC) based on their ability to retard the oxidation of natural indigo print paste while the paste remained on the screen frame. The results indicated that the retardation of arabic gum towards oxidation was the greatest among the four types of thickening agents. The highest K/S value of the printed cotton was observed with a dye concentration of 50g/L fermented indigo powder. The best printing results were obtained when the duration of dye efficiency was tested for the 10 minutes of the dye paste remaining on the screen with a thickening agent concentration of 26.56% that represented 530 cps viscosity. The test of colorfastness to washing and rubbing of the printed cotton resulted in grade 5, and the colorfastness to sunlight resulted in grade 4. Chinese traditional Naminwhapo printing was reproduced on cotton fabric using the natural indigo printing method derived from this study.

• 한국의류학회지
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• 제35권7호
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• pp.736-747
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• 2011

This study investigates the current status and dyeing properties of various natural indigo powder dyes in the domestic market. Products from India, China, Europe are sold in the market and only a few manufacturers provide recommendation for the method of dyeing and information on the additives. Through the market research and the preliminary investigation on 21 products, 11 were selected for the dyeing experiment which include 3 Indian, 3 Chinese, 2 German, and 1 Pakistani origin indigo reduced powders, and 2 Indian origin dried indigo leaf powder. The two dyeing methods used were the precipitation method and the fresh juice method, both at $10^{\circ}C$, $25^{\circ}C$, and $60^{\circ}C$. Color difference, K/S value, and colorfastness of dyed cotton fabrics were examined. Indian reduced indigo powder showed the highest K/S value, deep dyeing, and the best color fastness. Chinese reduced indigo powder resulted in a more greenish and bluish color. Powders of dried indigo leaves were easy to use but resulted in a pale color due to low dye uptake.

• 한국의류학회지
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• 제34권3호
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• pp.508-517
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• 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.

• 복식문화연구
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• 제24권6호
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• pp.777-787
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• 2016

This study was carried out in order to provide useful data for planning fabrics of summer eco-friendly fashion products. The fabrics used in this study were four cellulose fibers: cotton, cotton/mulberry blended, flax, and flax/lyocell blended. Dyeing with natural indigo was carried out under three different reducing conditions (i.e., general, eclectic, and eco-friendly) that have different reducing agent and pH levels, and hydrosulfite and glucose were used as a reducing agent. The dye uptake (K/S value) of fabrics dyed with natural indigo by a reducing condition was the highest at 660nm. Regardless of the fabrics, dye uptake was the highest under the general reducing condition and the lowest under the eco-friendly reducing condition. Under different reducing conditions, the dye uptake of natural indigo fabrics with the maximum absorption wavelength indicated a difference. The colorfastness of cellulose fabrics that were dyed with natural indigo had a rate of 4 to 5 except for rubbing fastness, which indicated good colorfastness. Additionally, natural indigo-dyed cotton and flax fabrics had good antibiosis. When the color characteristics of fabrics dyed with natural indigo were measured, all of the three reducing conditions created purple blue (PB) colors, and the color characteristics of dyed fabrics by reducing condition and fabric showed significant differences.

• 한국염색가공학회지
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• 제22권4호
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• pp.306-313
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• 2010

To achieve color diversification of natural dyeing, color mixture dyeing with Indigo and Japanese pagoda tree is applied to wool and silk fabrics. After dyeing with Japanese pagoda tree extract solution of 5~25%(o.w.f.), the indigo dyeing was carried out up to four times. Alternatively after repeat dyeing with indigo one to seven times, the dyeing with Japanese pagoda tree extract solution was applied in 5 steps(5~25%). In color mixture dyeing, the dye uptake of wool fabrics appears higher than that of silk. The sequence of Japanese pagoda tree extract dyeing after Indigo dyeing was generally higher dye uptake compared with that of Indigo dyeing after Japanese pagoda tree extract dyeing. For wool and silk fabric, the pre-dyeing with Japanese pagoda tree solution was more effective for color diversification but the pre-dyeing with Indigo was more effective for the exhibition of intermediate color shade.