Effect of gloss and texture on the color of injection-molded pigmented plastics

A model that describes the influence of gloss on the measured (reflected) color, initially developed for xero-graphic prints and which takes into account the geometry of the color measuring device, was applied to colored injection-molded plastics used in the interior of a car. The model is shown to give reasonable results for the material used (acrylonitrile-butadiene-styrene polymer) in four different colors. The gloss dependence of the measured color can also be expressed in terms of suitable surface topography descriptors, in this case the root-mean-square roughness and the lateral correlation length. The relation between the color of these pigmented plastics and material properties such as the light absorption and scattering coefficients is described using the Kubelka-Munk equation for pigment-paste mixtures. The scattering coefficient was found to be significantly affected by the surface texture, with a coarser texture giving a higher scattering. (c) 2005 Society of Plastics Engineers.