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The Development Of Cationic Dyes In China

Jun 19, 2017

    Cationic dyes are produced with the development of petrochemicals. In the 1950s, with the advent of acrylonitrile fibers, Geigy and Bayer of Germany have developed cationic dyes for acrylonitrile fibers. China in the early 60s have also been research and development to produce the first generation of a variety of cationic dyes. 70 years and the development of the second generation of X-type cationic dyes, to expand the chromatographic range, improve the dyeing performance, taking into account the compatibility between the ternary color. 70 years of trial production and production of the third generation of M-type cationic dyes, known as the migration of cationic dyes, can be applied to a variety of acrylonitrile fiber dyeing.Cationic Dyes

     The world's production of dyes in developed countries, the production of cationic dyes and alkaline dye production accounted for only 10% of the total output of dyes. China's cationic dye production in the 1990s was more than 2 thousand tons / year, accounting for more than 1% of total dyestuff production, but also part of the export. Cationic dyes in the X-type three primary colors and cationic pink FG and brilliant red 5GN for the larger varieties. In recent years at home and abroad to research and development of dyeing performance, special, new structure of the species, as well as the improvement of old products, energy saving, waste management and other fields.Cationic Dyes

    Cationic dyes on the affinity of acrylic, dyeing, due to rapid diffusion and slow diffusion, prone to uneven dyeing phenomenon, and once the uneven dyeing, it is difficult to extend the dyeing time by correcting. Cationic dye dyeing, in order to get a uniform staining results, should be appropriate to reduce the rate of dyeing. Factors affecting the dyeing rate of cationic dyes in addition to the types of acrylic, there are the following aspects:1. Temperature is an important factor in controlling leveling. When the dyeing temperature reaches the glass transition temperature (75-85 ℃), the dyeing rate of the dye increases rapidly. Therefore, when the dyeing temperature reaches the glass transition temperature of the fiber, it should slowly increase the temperature, generally every 2 ~ 4 min temperature l ℃. Can also be 85 ~ 90 ℃ when the insulation dyeing for some time, and then continue to heat up to boiling 2. Dyeing bath pH value, adding acid in dye bath, can inhibit the dissociation of acidic groups in acrylic fiber, reduce the number of anionic groups on the fiber, so that the Coulomb gravitational pull between the dye and fiber decreases, the dyeing rate decreases. The effect of pH on the dyeing rate is more significant with the carboxylic acid group-containing acrylic fiber, and the dyeing rate of the sulfonic acid group-containing acrylic fiber is less affected by the pH value of the bath. Dyeing should be reasonable control of the pH value of dye bath. Cationic dyes are generally not alkali, the best pH value of dyeing is generally 4-4.5, dyeing dark dye bath when the pH value can be higher, light color should be carried out at a lower pH value. The pH value of the dye bath is generally adjusted with acetic acid, acetic acid can reduce the dye bath pH value, but also improve the solubility of the dye. In the dye bath at the same time by adding sodium acetate, can stabilize the dye bath pH within the required range.Cationic Dyes