Pigments are substances that can dye objects. Dyes are substances that can color fibers and other materials, and the difference is that pigments can easily fade in a certain environment after coloring objects, while dyes are not easy to fall off and change color.
Pigments are insoluble in the medium, and dyes are dissolved in the medium (such as: water, solvent, oil, plastic or high molecular weight, etc.).
The pigment is in the form of particles in the medium, and the dye is in the form of molecules. Many surfaces are susceptible to damage, such as wind, snow, sunlight, rain, heat, friction, oxidation, chemicals, etc., which have corrosive effects.
Pigments usually have the following properties:
1. Color. Color pigments are pigments that selectively absorb and scatter visible light, and can present yellow, red, blue, green and other colors under natural light conditions.
2. Coloring power. The ability of colored pigments to absorb incident light. It can be expressed as a relative percentage of the tinting power of a standard pigment sample.
3. Covering power. The ability to cover the color of the substrate surface in the film-forming substance. It is usually expressed by the number of grams of pigment contained in a paint covering an area of 1 square meter.
4. Light resistance. The pigment retains its original color performance under certain light. Generally speaking, an eight-level system is used, and eight-level is the best.
5. Weather resistance. The ability of a pigment to maintain its original performance under certain natural or artificial climate conditions. Generally speaking, a five-level system is used, and five-level is the best.
6. Volatile matter. Mainly refers to moisture, generally stipulated not to exceed 1%.
7. Oil absorption. Refers to the number of grams of refined linseed oil required for 100 grams of pigment to form a uniform mass. The oil absorption is better. The oil absorption is related to the specific surface area and structure of the pigment particles.