Abstract
The present study describes the mechanical behavior of powder coatings used under very high compressive loads in clamping force joints.
Carboxyl functional polyester powder coatings cured with hydroxyl functional β-hydroxyalkylamides with variations in coating thickness and amount and type of filler, have been studied. The coatings were subjected to conventional tests for coatings and polymers and also to specially designed tests developed to study the behavior of powder coatings in clamping force joints. The specially designed tests were used to study the coatings under compressive loads, and the relation between the results from these test methods and from conventional tests is discussed.
The results show the importance of coating thickness in order to achieve the desired mechanical properties of a coating when used under high compressive loads. These loads put high demands on the stability of the coating, and the defects must be kept to a minimum. Increased thickness will give rise to more defects in the coating, especially voids and blisters due to the evaporation of water formed during the curing of the polyester powder coating. The surface roughness of the coating is also affected by the coating thickness, but the main influence originates from the type and amount of filler used. A rough surface will give rise to stress concentrations and increased plastic deformations in the coating, impairing the properties of the clamping force joint.
Similar content being viewed by others
References
Bergk, B., “Wet Coating in Competition with Powder Coating: Newest Trends in Environment Protection,”Ind. Lackierbetr., 56 (3), p. 82–6 (1988).
Bell, G.A., “Ultra Durable Powder Coatings for Automotive Applications,”Pigm. Resin Technol., 29 (5), p. 298–300 (2000).
Alfort, H.-J., “Powder Coatings in Europe—An Overview of New Developments,”Farbe Lack, 106 (9), p. 52,54,57–58 (2000).
Boogaerts, L., et al., “A New Polyester Resin for Beta.-Hydroxyalkylamide Powder Coatings,”Proc. 27th Int. Waterborne, High-Solids, Powder Coat. Symp., New Orleans, LA, p. 504–515, 2000.
Howell, D.M.,Volume 1 Powder Coatings. The Technology, Formulation and Application of Powder Coatings, Sanders, J.D. (Ed.) 361 pp., 2000.
Wicks, Z.W., Jones, F.N., and Pappas, S.P.,Organic Coatings: Science and Technology, 2nd ed., New York, Wiley, 630, 1999.
Van Benthem, R.A.T.M., Rietberg, J., and Stanssens, D.A.W., “Condensation Polymer Containing Hydroxyalkylamide Groups” inPCT Int. Appl., (DSM N.V., Neth.), Wo. p. 47, 1999.
Stanssens, D.A.W., Van Den Elshout, W.H.H.A., and Houweling, M., “Powder Coating Compositions with Hydroxyalkylamide Crosslinkers”, inPCT Int. Appl., (DSM N.V., Neth.), Wo. p. 15, 1994.
Belder, E.G., Rutten, H.J.J., and Perera, D.Y., “Cure Characterization of Powder Coatings,”Prog. Org. Coat., 42 (3–4), p. 142–149 (2001).
Hill, L.W., “Mechanical Properties of Coatings,” Miranda, T., (Ed.), Federation Series on Coatings Technology, Federation of Societies for Coatings Technology, Blue, Bell, PA, 1987.
Hill, L.W., “Structure/Property Relationships of Thermoset Coatings,”Journal of Coatings Technology,64, No. 808, 28 (1992).
Lange, J., “Curing of Thermoset Films: Build up of Structure and Residual Stresses” Ph.D. Thesis. Department of Polymer Technology, Royal Institute of Technology, Stockholm, Sweden, 1995.
Sullivan, J.L.H., D. “Bolt Load Retention: Observed versus Predicted,” inPolym. Mater. Sci. Eng. (1998).
Krupicka, A., “Use and Interpretation of Scratch Tests on Organic Coatings,” Doctoral Thesis Polymer Technology, Royal Institute of Technology, Stockholm, Sweden, 2002.
Nordström, L. and Österberg, L.,Lackskikts egenskaper i klämda skruvförband, IVF: Gothenbourg, p. 23, 2000.
Ståhlberg, D., et al., “Mechanical Response of Thermoset Polymers Under High Compressive Loads. Part I: Experimental,”Mechanics of Time-Dependent Materials, submitted for publication.
Nordin, L.-O., et al., “Mechanical Response of Thermoset Polymers Under High Compressive Loads, Part II: Modelling,”Mechanics of Time-Dependent Materials, submitted for publication.
Maxwell, B.E., et al., “Replacing Benzoin in Powder Coatings: Work Towards Understanding Benzoin’s Mode of Action,”Proc. 26th Int. Waterborne, High-Solids, Powder Coat. Symp., New Orleans, LA, p. 183–189, 2000.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
St»hlberg, D., Johansson, M. Properties of powder coatings in load carrying construction. J Coat Technol Res 2, 473–481 (2005). https://doi.org/10.1007/BF02733890
Issue Date:
DOI: https://doi.org/10.1007/BF02733890