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Effects of Atomization on the Particle Size, Appearance, and Composition of Automotive OEM Basecoats
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Abstract
Color uniformity in the automotive paint industry is a very important attribute. Previous work to better understand the factors responsible for basecoat color variation has concluded that dried film composition is the most important factor. This work continues to support that conclusion, and in addition, describes quantitatively how final film composition can be modified by small changes in the atomization of the basecoat.
Using an air-blast paint spray atomizer and a silver (aluminum flake containing) waterborne basecoat, sixteen (16) spray applied films were analyzed by inductively coupled plasma - atomic emission spectroscopy (ICP-AES) for pigment content. Analysis found that the ratio of “effect” to “color” pigments in the films (i.e., metallic flakes vs. colored pigments) changed by more than 60% when changes were made to the conditions of spray application; fluid flow [100 vs. 400 g/min.], shaping air flow [25 vs. 50 psi cap], and atomizing air flow [40 vs. 60 psi cap]. These results are significant as perceived color is highly correlated to the concentration of aluminum in the film. Formulation specialists can typically detect color differences in coatings when films vary in composition by less than 2%. For the casual observer, this lower limit is approximately 5%.
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Miller, R. and Brooks, G., "Effects of Atomization on the Particle Size, Appearance, and Composition of Automotive OEM Basecoats," SAE Technical Paper 980979, 1998, https://doi.org/10.4271/980979.Also In
References
- Bell, G. C. Hochberg, J. “ Mechanisms of Electrostatic Atomization, Transport, and Deposition of Coatings ,” Seventh International Conference in Organic Science and Technology Athens, Greece 1981
- Inkpen, S “ Electrical and Mechanical Mechanisms for Color Variation in the Spraying of Metallic Paints ,” Massachusetts Institute of Technology April 1986
- Tachi K. Okuda C. “ Color Variation of Automotive Metallic Finishes ,” Journal of Coatings Technology 64 811 Aug. 1992
- Larson, J. C. Miller, R. C. “ Spray Characterization ,” E. I. DuPont de Nemours and Company; Automotive - Refinish Finishes Marshall Research Laboratory.
- Chan, T. L. D'arcy, J. B. Schreck, R. M. “ High Solids Paint Overspray Aerosols in a Spray Painting Booth: Particle Size Analysis and Scrubber Efficiency ,” Am. Ind. Hyg. Assoc. J. 47 7 411 417 1986
- Domnick J. Lindenthal A. Tropea C. Xu T.H. “ Application of Phase Doppler Anemometry in Paint Sprays ,” Atomization and Sprays 4 437 450 1994
- Higuchi R. Kansai Paints Co., Ltd. “ Atomization of Paints by Air Streams ,” Shikizai Kyokaishi 42 4 155 63 1969
- Andou K. “ Atomizing Evaluation of Air Spray Gun ,” Shikizai Kyokaishi 65 7 415 20 1992
- Snyder H. E. Senser D. W. Lefebvre A. H. “ Mean Drop Sizes from Fan Spray Atomizers ,” Journal of Fluids Engineering 111 Sept. 1989
- Perry's Chemical Engineers' Handbook 6th McGraw Hill 5 63 1984
- Skoog D. A. Leary J. “ Principles of Instrumental Analysis ,” Saunders College Publish 4th 234 244
- X-Rite® Corporation Publication L10-024 “ Understanding Color Tolerancing ,” 3100 44th Street, S. W., Grandville, MI 49418
- Bachalo, W. D. Houser, M. J. “ Phase/Doppler Spray Analyzer for Simultaneous Measurements of Drop Size and Velocity Distributions ,” Optical Engineering September October 23 5 1984
- Lefebvre, A. H. Atomization and Sprays Hemisphere Publishing Corporation New York, New York 1989
- Hinds, W. C. Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles John Wiley & Sons New York, New York 1982