The traditional method to apply the colorant in plastic industry is making the colorant as powder. Now, many colorants can be made as Color Masterbatch, which is small plastic pellets with over-loaded color (2% to 5%, normally 2%). The advantages of using color masterbatch include:
1. Good disperibility of color in the plastics. Because the color-carrier plastic is same as the molding plastic, the color can be dispersed in the melted plastic more easily.
2. Stability of color. Sometimes the powder will absorb the moisture from the air and decompose then. However, colored plastic doesn’t have such problem.
3. Easier to weight so more accurate for measuring.
4. Avoid the powder flying in the air to keep worker’s health and environment cleanness.
In the industrial production, it is necessary to mix well colorant and the molding plastic before the mixture is sent into the molding machine. Sometimes, the raw materials supplying line will be equiped with a mixer that assures sufficient mixing. If mixing is not sufficient, the color of one batch of finished plastic is not consistent.