Basics of Dyes
The concept of dyes
Dyes are colored organic compounds that can be fiber materials to obtain color, but not all colored organic compounds can be used as dyes. There are generally four conditions that must be met in order to be used as a dye.
1
Color
That is, it must be able to dye a certain concentration of color (have a certain rate of dye enhancement)
2
Ability to take on color
That is, it has a certain binding power with the textile material, i.e. affinity or directness.
3
Solubility
That is, it can be directly dissolved in water or dissolved in water by chemical action.
4
Dyeing Firmness
That is, the color dyed on the textile material needs to have a certain durability, not easy to fade or change color.
Some colored substances are insoluble in water, no affinity for fibers, can not be counted inside the fiber, but can rely on the role of the adhesive mechanically fixed on the fabric, this material becomes pigment. Pigment and dispersant, hygroscopic agent, water, etc. for grinding, can be made of paint, paint can also be used for dyeing, but not as common as the application in printing.
Development and Classification of Dyes
Dyestuff production generally takes 1857 as the dividing line: before 1857 for the extraction and processing stage of natural dyestuffs; after 1857 for the production and processing stage of synthetic dyestuffs.
Classification of Dyes
There are two ways to classify dyestuffs, one is to classify them according to their properties and application methods, which becomes the application classification, and the other is to classify them according to their chemical structure or their characteristic groups, which is called the chemical classification.
1 Classification according to chemical structure
It is divided into: azo dyes, anthraquinone dyes, arylmethane dyes, indigo dyes, sulfide dyes, phthalocyanine dyes, nitro and nitroso dyes, in addition to other structural types of dyestuffs, such as methanoguan and multimethanoguan dyestuffs, stilbene dyestuffs, as well as a variety of heterocyclic dyestuffs, and so on.
2 Classification by application
Divided into: direct dyes, acid dyes, cationic dyes, reactive dyes, insoluble azo dyes, disperse dyes, reducing dyes, sulfur dyes, condensation dyes, fluorescent whiteners, in addition, there are also oxidizing dyes used in textiles (e.g., aniline black), solvent dyes, polypropylene dyes, as well as food pigments used in food, and so on.
Naming of Dyes
There are many kinds of dyestuffs. In order to meet the requirements of production and application, and to correctly reflect the color and application properties of dyestuffs, it is necessary to give special naming to dyestuffs.
According to the “Draft Nomenclature of Dyestuff Products”, which has been implemented by the former Ministry of Chemical Industry of China since January 1965, the nomenclature of dyestuffs in China – the three-part nomenclature is introduced as follows, the name of dyestuffs consists of three parts, i.e., “Crown”, “Color”, “Color”, “Color” and “Color”, The name of dyestuff consists of three parts, namely, “crown”, “color” and “character end”.
Coronation part – indicates the application category of dyestuff. In the international market, the trade name or application category of dyestuff indicates the coronation of dyestuff, while in the domestic market, the application classification or nature of dyestuff is used as the coronation of dyestuff.
In China, there are 31 kinds of dyestuffs such as Acid, Acid Complex, Acid Mordant, Neutral, Direct, Direct Sunlight Resistant, Direct Blend, Alkaline, Cationic, Reactive, Reduced, Soluble Reduced, Sulphurized, Sulphurized Reduced, Dispersed, Chromophenol, Chromophore, Colour Base, Colour Salt, Condensed, Fast Pigment, and so on.
Color section – marking the color of the dye on to the fiber, domestic and foreign basically the same.
The color name adopts twenty-nine color names: tender yellow, yellow, golden yellow, deep yellow, orange, red, red, peach, rose red, magenta, red violet, jujube red, purple, Cuilan, blue, blue, blue, blue, blue, blue, dark blue, green, green, green, green, dark green, yellow-brown, red-brown, brown, brown, brown, dark brown, olive green, green, grass green, gray, black.
For the adjectives of color, the words “tender”, “brilliant” and “dark” are used.
The end of the word – that is, a certain number of symbols and figures to illustrate the color and light, form, special properties and other dyeing properties.
Commonly used symbols and their meanings are listed
①Indicates the quality of the color light or color of the dye.
A The customary name of the dyestuff, such as Lake Blue A, Acid Red A.
B Indicates blue or greenish light.
G Indicates yellowish or greenish light.
R Indicates reddish color.
F denotes pure color light
D denotes dark or darker color
②Indicates properties and uses
AS Series name of insoluble azo dye color phenol, such as AS-D, etc.
B Bis(homotriazine) dyes, such as Megafix gold BES, etc.
C Indicates chlorine bleaching resistance, such as reducing blue BC, cotton; insoluble azo dyes hydrochloride, such as yellow-based GC.
D For dyeing, high temperature resistant blended direct dyes, such as direct blended yellow D-RL; high temperature type disperse dyes, such as Dispersol Orange D-G, can be printed reduction dyes, such as reduction brown RRD.
Dye Endnotes
In the endnotes of dyestuffs, it is also common to indicate the strength of the dyestuff, such as 100%, 200% and so on. The so-called dyestuff strength refers to the relative concentration determined by the dyestuff manufacturer by using a certain mass fraction as the standard of dyestuff strength (the strength is regarded as 100%), compared with other dyestuffs. For example, 50% means that the strength of a dye is half that of a standard dye. Different manufacturers have different power content standards, which are not comparable. Fillers such as dyeing promoters, diffusers, co-solvents and other auxiliaries are often added to dyestuffs by dyestuff factories, and care should be taken when using them.
