Rubber colorant is only insoluble in water and solvent called pigment, not soluble in water and organic solvent dyes, which should be distinguished as rubber formula designers. Pigment has no affinity with any different rubber. It is through the mechanical pressure of the rubber mixer, kneading and shearing action, so that the pigment particles are dispersed in the mixed rubber material that is colored, and the mixed rubber material produces the required color. In latex products, added to the emulsion [natural latex and synthetic latex and synthetic latex] of inorganic pigment process method and join into the dry glue method is completely different, not in the form of powder added to the natural latex and synthetic latex and synthetic latex, but to put the powder paint colorants, along with a small amount of dispersant, stabilizer and deionized water, With 20% or 30% of the water bulk, and then through the grinding machine grinding, to reach the specified value of settlement, according to the design of the number of mass, with latex or vulcanization, semi-vulcanization with latex added. Coloring water dispersion preparation of the total solid content must not be too high, otherwise grinding and dispersion effect is not good.

Colorant pigments for rubber [containing latex, the same below] can be divided into inorganic pigments and organic pigments according to different chemical composition.

Inorganic pigments are usually metal oxides, sulfides, sulfates, chromate, molybdate and other salts. The common characteristics of inorganic pigments are strong covering power, heat resistance, light resistance and weather resistance, small migration, the deficiency is poor coloring power, color brilliance is not enough, commonly used inorganic colorants. Some contain toxicity, do not meet environmental protection and health requirements, has been banned. Such as lead yellow, chromium orange, molybdenum chromium red, cadmium yellow, cadmium red and so on; Some have no toxicity, but to consider whether it contains heavy metals, such as titanium dioxide, titanium yellow, iron oxide yellow, chromium titanium yellow, zinc iron oxide, iron oxide red, group green, cobalt blue, chromium oxide green, spinel green and so on. All kinds of inorganic pigments added to rubber should be certified by relevant standards before they can be used.

Species than inorganic pigments, organic pigments have phthalocyanine class, the two hue, such as phthalocyanine green, blue, green, phthalocyanine blue, widely used surface 】, azo, [though many varieties, single azo chemical structure, double azo, and condensation azo, but also limited to red, orange, yellow hue, such as lake red C, 2 b], quetiapine acridine ketones, [hue has orange, red, purple three categories, Its heat resistance, light resistance and migration resistance are very good, similar to phthalocyanine pigments. Therefore, some manufacturers are used to call it phthalocyanine red, phthalocyanine violet and isoindolinone, with more yellow varieties, such as yellow 2GLT, red 2BLT, orange RLT]. Naphthalene tetracarboxylic acid and perylenetetracarboxylic acid derivatives [good heat and mobility, orange and red,] dioxazines [good light resistance and coloring power, such as permanent purple]. Organic pigments have distinct hue, strong coloring power, good dispersity, good migration resistance, but heat resistance and light resistance are poor, but a high temperature vulcanization is easy to change color, especially after two vulcanization.