Objective The application of natural dyes in textile printing and dyeing has attracted extensive attention because of their non-toxic and harmless characteristics. In order to improve the color yield and color fastness of plant dye dyeing products, mordant dyeing treatment is often needed in the dyeing process, but this will lead to long dyeing process and a large number of metal ions in wastewater. Metal ions were introduced into natural dye molecules in advance through complexation reaction to prepare metal complexed plant dyes, and their dyeing properties and influencing factors on textiles were studied in detail. These studies were deemed necessary for developing short dyeing process with natural dyes and achieving energy saving and emission reduction.Method In this paper, catechin-iron ion complex dye C-Fe was prepared by hydrothermal method through the coordination reaction between catechin and metal ion Fe 2+ . Fourier transform infrared spectroscopy（FT-IR）, ultraviolet visible spectrophotometer（UV-VIS）, scanning electron microscope energy spectrometer（EDS） and X-ray photoelectron spectroscopy（XPS） were adopted to characterize and analyze the structure of the complex dyes. The dyeing of a silk fabric with iron ion complexed catechin was studied by grinding dispersion method. The influences of technological parameters such as pH value, dyeing temperature and dye dosage on the K/S value of textiles were analyzed, and the technological conditions were optimized.Results Energy spectrum analysis of plant complex dyes showed that the C-Fe molecules contained not only C and O elements, but also Fe elements（Fig.2, Tab.1）. Based on the energy spectrum scanning component element content analysis and the structure analysis of the complex dye, the complex ratio of C-Fe molecule was calculated as 1：2. UV-VIS spectrum analysis showed that the maximum absorption wavelength of catechin was red shifted after complexation with metal ions, which was consistent with the law that the UV-VIS spectrum of dye molecules moved to the long wavelength direction caused by the attraction of metal ions to electrons（Fig.3）. IR spectrum analysis showed that the complex dye C-Fe produced a new absorption peak at 556 cm -1 , indicating that it was the stretching vibration peak of Fe—O bond formed after coordination（Fig.4）. X-ray photoelectron analysis showed that the peak position of Fe element was found at 706.7 eV for the complex dye C-Fe（Fig.5）. The coordination of metal ions had different effects on the whole molecular chemical environment. The complex dye occurred on the adjacent hydroxyl groups or the adjacent hydroxyl groups and carbonyl groups of the benzene ring（Fig.6, Fig.7, Tab.2 and Tab.3）.A complex dye suspension with an average particle size of 405.47 nm was obtained by grinding and dispersion（Fig.8）. The test showed that the optimal process parameters for dyeing silk fabrics with complex dye C-Fe were pH value of 4, dyeing temperature of 90 ℃, and temperature maintaining and continuous dyeing for 60 min（Fig.9, Fig.10 and Fig.11）. The color fastness to sunlight and rubbing of silk fabrics dyed with complex dye C-Fe reached grade 3, and the color fastness to perspiration and soaping were all above grade 4（Tab.4）. The UPF value of silk fabrics dyed with complex dye was 72, reflecting excellent ultraviolet protection performance（Tab.5）.Conclusion In this paper, plant complex dyes were prepared by the coordination reaction between plant dyes and metal ions, and then the silk fabric was dyed with good dyeing effect, and the fabric demonstrated good color fastness and UV resistance. The experimental results show that the preparation of plant complex dyes from plant dyes as raw materials is feasible for textile dyeing. It is expected to be developed as a short process technology for plant dye dyeing, which provides a theoretical basis for the development of metal complex natural dyes and their application in textile dyeing.

以铁离子络合羟基茜草素制备的络合染料(P-Fe)为研究对象,采用碱溶解和分散研磨两种方法对羊毛纤维进行染色.通过测试染色羊毛的K/S值和色牢度,研究P-Fe络合染料对羊毛织物的染色性能.结果表明:碱溶解和分散研磨染色法的最佳工艺均为染浴pH为4,染色温度100℃,时间60 min.两种方法染得羊毛纤维的耐日晒色牢度达到3级,耐汗渍色牢度、耐皂洗色牢度均在4级以上;分散研磨染色法所得纱线对金黄葡萄球菌和大肠埃希菌的抑菌率分别为82％和75％,体现出较好的抑菌效果.

为探索农业废弃物用作天然染料的可行性,以碧根果壳为对象,研究碧根果壳色素稳定性以及对真丝织物的染色性能.结果表明:碧根果壳色素具有较好的耐酸碱稳定性和耐光稳定性,金属离子可以通过络合反应改变碧根果壳色素的颜色;蚕丝织物的优化染色工艺为:温度90～95℃,时间40～60 min,pH为3.预媒染有利于提高染色织物的得色量,同浴媒染对染色织物的色牢度提升效果较好.

为了了解核桃色素对真丝织物的染色性能,试验了染色pH值、温度、时间、硫酸钠质量浓度等因素对核桃色素上染真丝织物的影响,并以硫酸铝和硫酸亚铁为媒染剂,研究了预媒染和后媒染工艺对核桃色素染色真丝的影响.结果 表明:核桃色素直接染色真丝织物的最佳工艺为染浴pH值为3,染色温度98℃,时间70 min,适当加入硫酸钠可提高匀染性;随着核桃色素用量的增加,染色织物的K/S值明显增大,但总体得色量不高;媒染对染色织物的颜色特征值和色牢度影响不大.

研究硫酸钠用量、pH、温度、时间等对儿茶色素上染真丝织物的影响,分析媒染剂硫酸铝对儿茶色素染色真丝的影响.结果表明,染色优化工艺:pH 4,90℃,70 min,加入适量硫酸钠可提高匀染性;随着儿茶色素用量增加,染色织物K/S值增大,但总体得色量不高;媒染对染色织物的颜色特征值和色牢度影响不大.