First understand the properties of Dispersed Green Orchid S-GL before you can understand the factors affecting the color flower of the dye itself. Disperse Blue S-GL (C.I.Disperse Blue 60) is a typical anthraquinone-type disperse dye with a molecular formula of C20H17N3O5 and a molecular weight of 379.37. The structural formula is as follows. It is green light on polyester fiber.
Domestic one-component dispersed emerald blue S-GL usually refers to the above structure. Its molecular weight of 379.37 is not considered a large molecule among disperse dyes. It may be due to the anthraquinone ring structure and The good sublimation fastness of Cuilan S-GL has caused everyone to think that Cuilan is a macromolecular disperse dye. As for the poor high-temperature dispersion or level dyeing properties of single-component dispersed green orchid, it is caused by many reasons and has nothing to do with its molecular weight. Some people say that the two-component dispersed green orchid has good level dyeing properties. As for why, the author believes that it includes dye application theory and dyeing theory, which cannot be explained clearly in a few words. Everyone is welcome to discuss. The quality of the domestic two-component dispersion Cuilan is also very good, which is no different from that of Huntsman and DyStar.
The influencing factors discussed in this article are based on good pre-treatment of polyester fiber or fabric.
1 The influence of dyeing water quality
The quality of dyeing water refers to Water hardness and metal ions.
For Dispersed Cuilan S-GL, the Mg2+ and Ca2+ in the water hardness index generally have a small impact on the dye color. However, when the concentration is high, it will also affect the color of the dye. Dyeing will have adverse effects, so it is recommended to use soft water during the Cuilan printing and dyeing process. Heavy metal ions in water often refer to copper, iron ions, etc. Especially iron ions will make the color of Cuilan S-GL darker, while copper ions have less impact on the color.
In the printing and dyeing process, iron elements exist in the following forms: iron powder, rust, Fe2+, Fe3+, etc. The combination of rust, Fe3+ and dyes causes the green light to deviate, and iron powder and Fe2+ not only Combining with dyes causes Cuilan to produce a color deviation, and it also has certain reducing properties. The printing and dyeing process under acidic conditions also promotes the production of iron powder and Fe2+ reducing properties.
2 Effect of dyeing pH
Dispersed Emerald Blue S-GL The applicable range of dyeing pH described in relevant literature and dye index is 3 to 9. So why is Cuilan said to be more sensitive to pH? It is generally recommended to control the pH for dyeing. This may be due to two reasons: 1. The biggest characteristics of Cuilan The color is bright, and a slight deviation of the bright color will be obvious to human vision, so the requirements for printing and dyeing are relatively high; 2. The influence of iron ions and comprehensive economic costs, the pH should be adjusted to a narrow, weakly acidic condition , iron ions will not combine or aggregate with dyes, so they will not cause color flowers or color differences.
Preventive measures:
1. Add metal ion chelating agent. For Fe2+, Fe3+, and Cu2+, metal chelating agents containing EDTA or NTA that are effective in acid and neutral dye baths can be used. For Mg2+ and Ca2+, polycarboxylic acid metal chelating agents can generally be used.
2. Strictly control the dyeing pH value between 4.5-5.0 so that the ferric ions will not settle or bind to the dye. It is recommended to use glacial acetic acid + Sodium acetate buffer system.
3. Add an appropriate amount of weak oxidizing agent, the dosage must be tested in the laboratory first, such as sodium chlorate, anti-staining salt S, etc.
Solution to colored flowers:
Use 0.6g/L oxalic acid, boil in water at 60℃×20min (laboratory required Do a small trial first).
3 Dye Selection and Dyeing Process Control
Dispersed Emerald Blue S-GL is not suitable as the three primary colors. In the printing and dyeing industry, it is generally used to combine light aqua blue (color matching with dispersed brilliant blue 2BLN), brilliant green (color matching with bright yellow 3G, 7G, fluorescent yellow 8G, 10G), dark blue-green (color matching) Brilliant blue 2BLN or green 6B, yellow 3G, 7G color matching), etc. The above dyes are available in low-temperature, medium-temperature, and high-temperature types for color matching with Cuilan. Their compatibility with Cuilan is not ideal, but such dyeing formulas exist objectively.
The glass transition temperature of polyester fiber is 70-80℃. After reaching 80℃, disperse dyes begin to dye. The dyeing speed accelerates at 90℃. The fastest speed is 110℃. 90 Colored flowers are most likely to occur at ~110°C. The measures taken by the dyeing factory are to control the heating rate within 1°C/min, and to maintain heat in stages at 90°C, 100°C, 110°C, and 120°C. Even so, problems such as color flowers and color differences may still occur.
Just think about why. In addition to the above-mentioned dyeing medium factors, above the glass transition temperature of polyester, the dye dyeing channel in the amorphous area of polyester fiber has been opened, but each The characteristics of the dye itself are different from the resistance to the external environment. Specifically, the crystal morphology of the dye molecule, the structural characteristics of the dye, the solubility of the dye, the affinity of the dye to the fiber, the affinity between the dye and the dye, and the binding force between the dye and the additives are all There are differences, and the dyeing speed is not synchronized or uniform. These are microscopic factors that cause color flowers and color differences. Macroscopically, it manifests as color flowers, color spots, color difference, layer difference, etc.
Improvement method:
Add an appropriate amount of leveling agent and dispersant to improve the asynchrony of dyeing and high temperature Dispersion stability.
Need to be classified into three categories:
Two misunderstandings:
1. Dispersed Cuilan S-GL products already have a large amount of dispersants. Is it necessary to add dispersants when dyeing? The author believes that it is necessary to add dispersants with good high-temperature stability, especially Cuilan type in thick and heavy colors. , tight fabric or yarnThread dyeing, such as suede, zipper cloth, cheese yarn, etc., is an important method to improve the color of green orchid flowers by improving their dispersion under high temperature or preventing the dye from re-condensing under high temperature.
2. Many technicians think that green is easy to color, so they increase the use of leveling agents. However, they do not know that they have already entered medium to dark colors, or even extremely dark colors. The dyeing depth is Refers to the total dye usage. Improper addition of leveling agent will not only cause the problem of “decolorization”, but also serious “dye aggregation”, which is a fatal factor for the color blooming of green orchid dyes.
4 “Discoloration” of Dispersed Emerald Blue S-GL staining
Disperse 60# Emerald Blue S-GL is a high-temperature dye with a macromolecular anthraquinone structure. When dyeing, please pay attention to:
❶Select the synchronous high-temperature dye, and the dyeing formula should not be high-temperature. Try to avoid incompatible dyes.
❷ Cuilan is very sensitive to pH value, so the amount of acetic acid should not be less. Ensure that the dyeing pH value is controlled between 4 and 5.5 before and after dyeing. If necessary, add a pH sliding agent.
❸The key factor affecting the dyeing stability of Cuilan is the high-temperature leveling agent, which has an excellent retarding effect, but the amount should not be too much, otherwise the color will become lighter. A salt-resistant leveling agent would be better (mainly because the recycled water has a high salt content).
❹A large amount of diffusion agents, anti-settling agents and other additives are added during the production of dyes, which are sensitive to water quality. Calcium and magnesium ions in the water easily combine with dyes to produce color spots, especially iron. Ions have the greatest impact, so chelating dispersants must be added, which is good for the color purity and brilliance of the cloth surface.
❺The glass transition temperature of polyester is as low as 70-80°C. After reaching 80°C, disperse dyes begin to dye, and the dyeing speeds up at 90°, and the fastest is 110°! At this time, it is easiest to control the temperature rise rate within 1°C/min; it is best to keep the temperature for ten minutes at 90°C, 110°C, and 120°C. For high-temperature S-GL dyeing, the dyeing temperature should be increased to 135°C. The dyeing properties are the best, the dyeing is even, the discoloration is small, and the fastness is good!
❻Disperse dye dyeing on polyester is different from other dyes. It is prone to sublimation and thermal migration, which affects color fastness and color change. During finishing, the setting temperature should not be too high. It is best around 160℃.
❼Domestic one-component dispersion emerald blue S-GL has a relatively large molecular weight. Ordinary dispersion leveling agents have dispersion properties at medium and low temperatures, but may be turbid at high temperatures. Point problems will be weakly positive, and the dispersion performance will basically be lost, which will cause the dye molecules to agglomerate and become larger, and the leveling power will decrease, resulting in colored flowers and stains. Be sure to choose a special leveling agent; the dye is recommended to use two-component emerald blue, which has good leveling properties. Domestic BGE emerald blue and imported emerald blue from DyStar and Huntsman.
❽Analysis of the causes of yellowish and dark dyeing:
❏The pH value of dyeing is unstable, and alkaline substances are used as the dyeing temperature increases. The precipitation pH tends to be moderately alkaline.
❏Reducing substances such as sodium lignosulfonate in the dye and formic acid or citric acid in the dye liquor have a great influence on the discoloration of Cuilan. It is best to add dye resist Salt S.
❏It is recommended to avoid reused water if you are sensitive to green orchid green. When dyeing, the color will turn green and dark when exposed to iron ions. The color will also change slightly when exposed to copper ions. It absorbs the most Wavelength (λmax) 670nm, add chelating dispersant to reduce color change.
❏ Set the shape at a low temperature as much as possible within the requirements of the fabric surface. </p
