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

Abstract

A model that describes the influence of gloss on the measured (reflected) color, initially developed for xerographic 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. POLYM. ENG. SCI., 45: 733-744, 2005.

Color changes due to thermal ageing and artificial weathering of pigmented and textured ABS

“…The lightness of the glossy plaque did not virtually change due to the treatment, whereas those with a fine and coarse finish became visible darker (0.5–0.6 units). To some extent this is in accordance with the notion that color changes are more evident in case of samples with a low gloss [13]. The ageing resulted in a decrease along the red–green axis (the a *‐value) which is in contrast to the behavior of the naturally colored ABS, cf Fig.…”

“…Interior components in automotive (and other details) are often textured in order to enhance their appearance in a positive manner. It is known that optical properties such as color and gloss of the component depend on the type of surface texture [13, 14]. It is of significant interest to assess if the ageing results in different courses of events with regard to the color change depending on the type of surface texture.…”

Roughness of pigment coatings and its influence on gloss

“…It has been shown that increasing roughness (amplitude) increases the spreading of reflected light, thus increasing diffuse scattering and reducing gloss [8][9][10]12,15,16]. Also the lateral distribution of topographical heights (wavelength) has been shown to affect light scattering and gloss [12,16]. Problems in correlating gloss and surface roughness have been encountered related to accuracy of characterizing surface roughness (e.g.…”

“…gloss) and its dependence on factors such as coating color formulation, particle packing, pore structure and especially refractive index and surface roughness [8][9][10][12][13][14][15][16]. It has been shown that increasing roughness (amplitude) increases the spreading of reflected light, thus increasing diffuse scattering and reducing gloss [8][9][10]12,15,16]. Also the lateral distribution of topographical heights (wavelength) has been shown to affect light scattering and gloss [12,16].…”

The Influence of the Measuring/Viewing Angle on the Color of Injection-Molded Plastics

“…The change in lightness was more pronounced for the dark specimens whereas the corresponding change for the other two colors was quite small in the region between 45 and 110 . Note that a well trained colorist can detect difference in lightness of the order of 0.2-0.3 (diffuse illumination) [10] which indicates that the changes shown in Figure 5 should be quite visible. The texture also had an effect on the L Ã -value and its dependence on the measuring angle as is shown in Figure 6 in the case of the grey plaques.…”