Why are polyester color masterbatches divided into injection molding grade, spinning grade, and film grade?

Reasons for classification

polyester color masterbatches are classified into injection molding grade, spinning grade, and film grade based on the different downstream processing techniques and molding methods. There are significant differences in the requirements for the dispersion, purity, and flow characteristics of the masterbatch. The classification is done to adapt to different production scenarios and reduce processing defects. 

Spinning grade color masterbatches mainly supply fiber spinning processes. During spinning, the melt needs to pass through tiny spinnerets, and there are very high requirements for impurities, particle fineness, and dispersion uniformity. If the dispersion is not good, problems such as blockages, broken fibers, and fuzz can occur. At the same time, color fastness needs to be considered, and it should be adapted to subsequent stretching and setting processes. 

Injection molding grade color masterbatches are mostly used for the molding of various plastic parts. The flow channels and mold cavity space of the injection molding process are relatively spacious, and the focus is on the uniformity of coloration, heat resistance stability, and compatibility with the base material. It needs to adapt to the shear environment during the injection process to ensure uniform surface color and reduce color differences and spots, meeting the appearance and usage requirements of the plastic parts. 

Film grade color masterbatches serve the film extrusion molding process. The finished film products are thin, and strict control is required for crystal points and fish eyes. The masterbatch needs to be finely dispersed to avoid forming defects on the film surface. At the same time, transparency and covering power need to be considered to ensure that the film does not break during the stretching process and the color is transparent and uniform. 

Summary of selection

The carrier systems and additive formulations of the three types of color masterbatches have been specifically adjusted. They cannot be mixed randomly. The spinning masterbatches used for injection molding generally have fewer problems, but directly using injection molding masterbatches for spinning is very likely to cause production failures; film scenarios have strict control over impurities, and it is not suitable to use ordinary injection molding masterbatches. When purchasing, prioritize matching the processing technology, combined with equipment, product appearance, and post-treatment requirements, to ensure stable production yield. 

If you need to consult about polyester color masterbatches samples, please feel free to contact us.