Understanding dispersion of copper phthalocyanine alpha blue pigment in polyethylene masterbatch with the use of wax

Abstract

AbstractColoured plastics and polymers are widely used in packaging and consumer goods. Despite their critical roles, there is limited literature on detailed analysis of effective pigment dispersion in polymer matrices for masterbatch applications. In this study, detailed research was conducted on pigment dispersion using different wax materials and their performances in polyethylene masterbatches were compared. During the study, it was first found that the presence of salt crystals plays a critical role in dispersion in one of the tested pigments. Using a laser particle size device, it was shown that homogeneous particle size distribution is another critical parameter for proper pigment distribution. Although filter testing is a common method in industrial applications, there is very limited information in the academic literature. The filter test method was used to examine the effects of different polyethylene waxes on pigment dispersion. The best filter pressure values were obtained in masterbatches made with micronised wax. It was also observed that the improved dispersion increased the mechanical properties of the masterbatch. The masterbatch colours were measured with a sphere spectrophotometer and it was observed that uniform pigment distribution increased the colour strengths. Similar results were also seen in polyethylene films produced by the blown film process.