Fabric Products,Fabric Information,Fabric Factories,Fabric Suppliers Fabric News Very strange! Why does Disperse Emerald Blue S-GL dyeing “discolor” so easily?

Very strange! Why does Disperse Emerald Blue S-GL dyeing “discolor” so easily?

Knowledge of Dispersed Green Orchid S-GL First understand the properties of Dispersed Green Orchid S-GL before you can understand the factors that affect the color of the dye itself. Disperse Blue S-GL (C.I.Dis…

Knowledge of Dispersed Green Orchid S-GL

First understand the properties of Dispersed Green Orchid S-GL before you can understand the factors that affect the color 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 single-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 Due to the anthraquinone ring structure and the good sublimation fastness of Cuilan S-GL, everyone thinks 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.

Influence of dyeing water quality

The quality of dyeing water refers to the hardness and metal ions of the water.

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. Iron elements in printing and dyeing processes exist in the following forms: iron powder, rust, Fe2+, Fe3+, etc. The combination of rust and Fe3+ with dyes causes the color deviation of Cuilan, while iron powder and Fe2+ not only combine with dyes to cause color deviation of Cuilan, but also have certain Reducibility, and printing and dyeing processing under acidic conditions also promotes the reduction of iron powder and Fe2+.

The influence of dyeing pH

Dispersed Emerald Blue S-GL is introduced in relevant literature and dye index The dyeing pH applicable range is 3 to 9, so why is it said that Cuilan is more sensitive to pH? Generally, it is recommended to control the pH for dyeing. This may be due to two reasons: 1. The biggest feature of Cuilan is its bright color and bright color. A slight deviation will be obvious to human vision, so the requirements in printing and dyeing processing are relatively high; 2. The impact of iron ions, comprehensive economic costs, the appropriate amount of pH in a narrow, weakly acidic condition, iron ions will not interact with the dye Combining or aggregating, it will not cause color flowers or color difference.

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: boil with 0.6g/L oxalic acid at 60℃×20min (a small test in the laboratory is required).

Dye Selection and Dyeing Process Control

Dispersed Emerald Blue S-GL is not suitable as The three primary colors are generally used in the printing and dyeing industry 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 ​​the polyester fiber has been opened, but each dye has different characteristics and resistance to the external environment. Specifically, there are differences in the crystal morphology of dye molecules, the structural characteristics of dyes, the solubility of dyes, the affinity of dyes to fibers, the affinity between dyes, and the binding force between dyes and auxiliaries. The dyeing speed is not synchronous or uniform. These are the 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.

It needs to be classified into three categories:

Two misunderstandings

1. There is already a large amount of dispersant in Disperse Cuilan S-GL products, which is still necessary when dyeing.Should I add a dispersant? I think it is necessary to add a dispersant with good high temperature stability, especially when dyeing heavy, tight fabrics or yarns, such as suede, zipper cloth, cheese yarn, etc., to improve the quality of the dispersant. Dispersion under high temperature, or prevention of dye re-aggregation under high temperature, is an important method to improve the color of green orchid flowers.

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 “color loss”, but also serious “dye agglomeration phenomenon”, which is a fatal factor for the color flowers of green orchid dyes.

Dispersed Emerald Blue S-GL staining “discoloration”

Dispersed 60# Emerald Blue S-GL is a high-temperature dye with a macromolecular anthraquinone structure

Pay attention when dyeing

[1] Choose simultaneous high-temperature dyes, and try to avoid incompatible non-high-temperature dyes in dyeing formulas.

[2] Cuilan is very sensitive to pH value. 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 pH sliding agent.

[3] The 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 change. Shallow, salt-resistant leveling agent will be better (mainly because the recycled water has a high salt content).

[4] During the production of dyes, a large amount of diffusion agents, anti-settling agents and other additives are added, which are sensitive to water quality. Calcium and magnesium ions in the water easily combine with dyes to produce color spots, especially It is iron ions that have the greatest impact. Chelating dispersants must be added, which is good for the color purity and brilliance of the cloth surface.

[5] The glass transition temperature of polyester is lower than 70-80°C. After reaching 80°C, disperse dyes begin to dye, and dyeing accelerates at 90°, and 110° is the fastest! 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!

[6] Disperse 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 cannot be Too high is best around 160℃.

[7] Domestic one-component dispersed emerald blue S-GL has a relatively large molecular weight. Ordinary dispersed leveling agents have dispersing properties at medium and low temperatures, but may not be effective at high temperatures. The cloud point problem will be weakly positive, and the dispersion performance will be basically 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 leveling dye. Well, domestic BGE emerald blue and imported emerald blue from DyStar and Huntsman.

[8] Analysis of the causes of yellowish and dark dyeing:

ØThe dyeing pH value is unstable, and as the dyeing temperature increases, the alkali The pH of the precipitation of chemical substances tends to be moderately alkaline.

ØReducing 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.

ØIt 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.

ØSet at as low a temperature as possible within the fabric requirements! </p

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Author: clsrich

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