Effects of the extrusion processes on the rheological, chemical, and coloration properties of a copper phthalocyanine-based masterbatch

The production process of a monodispersed blue masterbatch for the coloration of the carpet filaments, constituted by a polyamide 6 (PA6) resin and a copper blue phthalocyanine pigment, was investigated and optimized. It was found that a compounding process based on three extrusions without any subsequent filtration was the best way to achieve a fine pigment dispersion within the PA6 matrix, with a filter pressure value reduction of 50% and a relative color strength increase of about 10% with respect to the standard production process (i.e. a single extrusion). Rheological tests, viscosity measurements and end groups analyses were used to determine the thermal stability of the prepared compounds. It was found that the triple extrusion promoted thermo-oxidative reactions. This innovative process setup can reduce the production waste, increasing the productivity and the quality of the final product without compromising the rheological properties of the monodispersed masterbatches.