On the relation between surface texture and gloss of injection‐molded pigmented plastics

The relation between the surface topography of injection-molded plastic objects with deliberately imposed textures and their gloss, measured by means of a conventional glossmeter at incident angles of 20°, 60°, and 85°, was investigated. A modification of the general scalar Kirchhoff approximation, which accounts for geometrical features of the glossmeter, is used to describe the experimental gloss values of the textured surfaces. The agreement between the measured and the calculated values for incidence angles of 20° and 60° confirms the usefulness of the approach, though several of the textured surfaces used here are too rough for the Kirchhoff theory to be strictly valid. A poorer agreement, however, was noted at higher incidence angles (85° in this case). For very smooth surfaces (without any texture), the classical Bennett-Porteus theory could in many cases describe the gloss level with sufficient accuracy. The influence on the measured gloss of the polymer material (in terms of its refractive index) and the color of the injection-molded object is also discussed. Light beige specimens in three different polymeric materials (acrylonitrile-butadiene-styrene, acrylonitrile-butadiene-styrene/polycarbonate blend, and polypropylene) as well as three acrylonitrile-butadiene-styrene products with different colors were used. The refractive index of the polymer had no major influence on the measured gloss. The gloss level increased slightly with increasing lightness of the specimens, which can be associated with an increased contribution from the bulk scattering. However, the surface texture governed most of the gloss variations. POLYM. ENG. SCI., 45:1343–1356, 2005. © 2005 Society of Plastics Engineers

[1]  C. Guerrero,et al.  Surface roughness in dynamically crystallized isotactic polypropylene films , 2004 .

[2]  Peter Z. Takacs,et al.  Light scattering from non-Gaussian surfaces , 1995, Optics & Photonics.

[3]  E. Dalal,et al.  The effect of gloss on color , 1999 .

[4]  H. E. Bennett,et al.  Relation between Surface Roughness and Specular Reflectance at Normal Incidence , 1961 .

[5]  Lars Mattsson,et al.  Assessment of surface finish on bulk scattering materials: A comparison between optical laser stylus and mechanical stylus profilometers , 1993 .

[6]  Mikael Rigdahl,et al.  Effect of gloss and texture on the color of injection-molded pigmented plastics , 2005 .

[7]  Maria E. Nadal,et al.  New primary standard for specular gloss measurements , 2000 .

[8]  R. Barrera,et al.  Surface correlation effects on gloss , 1998 .

[9]  J. Zavada,et al.  Relationship between surface scattering and microtopographic features (A) , 1979 .

[10]  Hjalmar Granberg,et al.  Forward scattering of fiber-containing surfaces studied by 3-D reflectance distribution simulations and measurements , 2003 .

[11]  E. Andreassen,et al.  Haze of polyethylene films—effects of material parameters and clarifying agents , 2002 .

[12]  J. P. Rahn,et al.  Relationship of the total integrated scattering from multilayer-coated optics to angle of incidence, polarization, correlation length, and roughness cross-correlation properties. , 1983, Applied optics.

[13]  E Marx,et al.  Light scattering from glossy coatings on paper. , 1991, Applied optics.

[14]  Per-Åke Johansson,et al.  Surface texture characterization of injection-molded pigmented plastics , 2004 .

[15]  L. Rayleigh,et al.  The theory of sound , 1894 .

[16]  J. Ogilvy,et al.  Theory of Wave Scattering From Random Rough Surfaces , 1991 .

[17]  M. P. Cook,et al.  Evaluation of gloss meters for measurement of moulded plastics , 1990 .

[18]  Manuel Nieto-Vesperinas,et al.  Scattering and diffraction in physical optics , 2006 .

[19]  Hans G. Völz,et al.  Industrial Color Testing: Fundamentals and Techniques , 1995 .

[20]  E. Stijns,et al.  Electropolishing of aluminium: processing and assessment of visual appearance , 2003 .

[21]  D. L. Macadam,et al.  The measurement of appearance , 1975 .

[22]  Light scattering by injection molded particle filled polymers , 1994 .

[23]  I. Ariño,et al.  Color of pigmented plastics—Measurements and predictions , 2004 .

[24]  A. Rey,et al.  Surface topography and gloss of polyolefin blown films , 2000 .

[25]  Girish S. Agarwal,et al.  Scattering from rough surfaces , 1975 .

[26]  G. Heinrich,et al.  Rubber Friction on Self-Affine Road Tracks , 2000 .

[27]  Solomon Musikant,et al.  Optical Materials: An Introduction to Selection and Application , 1985 .

[28]  Ari T. Friberg,et al.  Scattering from slightly rough random surfaces: a detailed study on the validity of the small perturbation method , 1990 .