Whether it is dyes or pigments, they are all substances that can give people the color they need. The existence of red, orange, yellow, green, cyan, blue, and purple enriches our lives and makes the world a better place. colorful.
Pigments and dyes are both colored organic compounds. From the chemical structure of organic pigments and dyes, they are very similar. Even some organic compounds can be used as dyes and organic pigments, but organic pigments and dyes are indeed Two different concepts, so what is the fundamental difference between dyes and pigments?
basic concepts
Dyes are organic compounds that can dye fibers or other substrates into a certain color. Most of them are soluble in water, or converted into a soluble state during dyeing through certain chemical treatments. Some dyes are insoluble in water but soluble in alcohol and oil, and can be used for the coloring of oil wax, plastic and other substances.
Pigments are colored organic or inorganic colored compounds that are insoluble in water and general organic solvents, but not all colored substances can be used as organic pigments. To become pigments, colored substances must have the following properties:
1. The color is bright, which can give the colored object (or substrate) a firm color and luster
2. Insoluble in water, organic solvent or application medium
3. It is easy to disperse uniformly in the application, and it is not affected by the physical and chemical effects of the application medium during the whole dispersion process, and retains their own inherent crystal structure.
4. Sunlight resistance, weather resistance, heat resistance, acid and alkali resistance and organic solvent resistance.
different coloring methods
The dye is dissolved in the resin;
Pigments are uniformly dispersed in the resin.
Difference in color change
Dyes are generally dissolved in the medium during use. Even disperse dyes or vat dyes undergo a process of first dissolving in water from a crystalline state to a molecular state and then dyeing on the fibers during dyeing. The color of the dye itself does not represent its color on the fabric.
Since the pigment is insoluble in the use medium during the use process, it always exists in the original crystal state. Therefore, the color of the pigment itself represents its color on the substrate.
different main uses
The main use of dyes is to dye and print textiles;
The traditional use of pigments is to color non-textiles such as inks, paints, coatings, plastics, rubber, etc. This is because dyes have affinity (or directness) for textiles and can be adsorbed and fixed by fiber molecules, while pigments have no affinity for all coloring objects, and mainly rely on resins, adhesives and other film-forming substances to combine with the coloring objects together.
Transparency contrast
The plastic made of dye is very transparent;
The transparency of plastics made of pigments is much worse. It is not excluded that there are transparent pigments, but there is still a certain gap between the transparency and the dyes.
Although dyes and pigments are different concepts, they can be used in general under certain circumstances. For example, some anthraquinone vat dyes are insoluble dyes, but they can also be used as pigments after pigmentation. Such dyes Known as pigment dyes, or dye pigments.
