Effect pigment masterbatch technology to help manufacturers enhance product appearance, quality

Advanced technology and know-how to process effect pigment master batch with minimum damage to the mica structure has been introduced by STEER. This is a welcome relief for manufacturers struggling with issues related to product appearance, quality and higher reject rates. STEER is a creator of materials platform technology that transforms and functionalises materials in the fields of plastics, pharmaceuticals. food & nutraceuticals, biomaterials and bio-refining. Effect pigments are used in thermoplastics to produce products with an aesthetically pleasing appearance. However, because of the sensitivity of the mica structure, damage occurs to the pigment during compounding, particularly during master batch production, where high volumes of free powders are introduced into the extruder. Speaking on Processing Mica-based Pigments, Robert Roden, Head - Global Compounding and ADC, STEER, said, “Pre-wetting of the pigment is particularly important prior to dispersion. Effective wetting is achieved through the use of proper mixing attributes, including elongation, laminar, and surface renewal, and by maintaining a low melt viscosity. For dispersive mixing the use of standard two lobe kneading blocks should be avoided due to their characteristic shear peaks and non-homogeneity of mixing energy input. Excessive energy input and damage to mica pigment cannot be avoided.” Four distinct and important steps were adopted while processing effect pigments into a compound— Wetting, Dispersion, Distribution, Stabilizing. STEER’s Omega 1.71 Do/DI platform technology with low shear signature was customized for precise implementation of the required steps to reduce pigment damage and wastage, protect quality and ensure an effective and economical product. Product quality is improved through the utilization of fully intermeshing multi-lobe mixing elements, such as STEER’s patented Fractional-Lobe special elements; these significantly reduce or eliminate shear peaks and possess highly efficient task-specific mixing functions. Moreover, pigment distribution, or homogeneity, is important to ensure that there is a uniform surface appearance in molded parts. STEER’s mixing elements possess excellent dispersive mixing characteristics so that a separate distribution process section is not required. “For additional distributive mixing STEER”S special self-wiping elements with fully intermeshing characteristics to prevent stagnation and degradation of the resin is used. This reduces the reject rate of the final molded part by reducing color body formation”, added Roden.