Colouring plastic is an important procedure in the production and processing of plastic products. It is of great significance for the processing of many plastic products, especially in the case of more and more customized production, the requirements for color are also an important part.

　　For colouring plastic, several common methods are mainly colored powder coloring, color paste coloring, liquid colorant coloring and color masterbatch coloring.

　　1. Toner coloring method. The method of directly coloring plastic particles with toner (pigment or dye) and an appropriate amount of powdery additives, also known as dry coloring, has the advantages of good dispersion, low cost and small batch operation.

　　2. Paste coloring method. The traditional color paste coloring is to use pigment powder directly added to the coating, or some coating manufacturers simply make the pigment into slurry, and then add it to the coating to color the coating.

　　3. Liquid colorant method. Liquid colorant is formed by dispersing colorant in organic liquid with high concentration. This colorant has good dispersibility and easy to use.

　　4. Masterbatch coloring method. The so-called Color Masterbatch means that the pigment (or dye) is mixed into the carrier under the action of additives by using a certain process and corresponding equipment, and the molecules of pigment powder and carrier resin are fully combined through heating, plasticizing, stirring and shearing, and then made into particles of similar size to resin particles.