Plastic colouring is an important link in plastic production and processing. Plastic products often have some requirements for color, and under these requirements, it is necessary to make different colors according to the design, so there is plastic colouring. So what are the general methods of plastic colouring?

　　1. Dry staining. Put a certain proportion of dye and plastic pellets into the rotating drum, and add 0.01% ~ 0.1% zinc stearate or white mineral oil as wetting agent to make the plastic easy to bond with the dye. Rotate the drum to completely mix the plastic and dye evenly.

　　2. Extrusion dyeing. In this method, the dye and plastic are mixed according to the dry dyeing method, and then extruded into a thin strip with a special extruder and cut into granules. The color mixing of this method is good and helps to disperse bad pigments.

　　3. Dry dense staining. This method is basically the same as the extrusion dyeing method. The difference is that the proportion of dyes in plastics is more than 10 times higher than usual. Multiple primary color plastics can be added to dilute during injection molding.