Umformbare polymerbeschichtete Bleche - Polymerphysikalische Charakterisierung und Struktur/Eigenschafts-Beziehungen

Translated title of the contribution: Multilayer coil-coated steel sheets - Polymerphysical characterization and structure/property-relationships

Michael Buder-Stroißnigg

Research output: ThesisDoctoral Thesis

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Abstract

Coil coating is a high performance technique for the continuous application of 1 to 4 advanced organic thermoset coating layers on a metal strip. According to the principle finish first fabricate later, coil coating offers an opportunity to substitute the conventional spray finishing during the manufacturing of automotive exterior body parts. The main objective of the thesis was to establish a fundamental understanding of the effects of material specific parameters and the overall deformation dependent performance of coil coated steel sheets. The scientific approach included the development and implementation of advanced measurement and testing techniques for coil coating layers and steel sheets, the selection, preparation and characterization of single coil coating layers and multilayer coated sheets and the establishment of correlations between material specific parameters and the overall performance characteristics of coilcoated steel sheets. By varying the binder, the cross linking agent, the pigmentation and the curing conditions stain-at-break-values for clear coating films ranging from 2 to 200 % were obtained. The structural parameter molar mass per hydroxyl number of the binder correlated with the glass transition temperature, the elastic modulus and the tensile strength of the clear coat films. The formability of coated steel sheets did not correlate with structural parameters and the glass transition temperature of the coatings. As to scratch resistance of the coated sheets a direct correlation with the glass transition temperature and the cross linking density of the coating films was established. The deformation induced changes of the appearance correlated with the average slope of roughness asperities. It was shown, that the appearance relevant topography is mainly determined by deformation dependent surface structure formation of the metallic substrate. The application of basecoat and clearcoat layers lead to a leveling of the appearance relevant structures on the substrate and primer surfaces. The parameter distinctness of image was more significantly affected by deformation of the coated steel sheet than gloss values. Hence different relationships between topographical parameters and distinctness of image as well as gloss were obtained on the different lateral scales investigated.
Translated title of the contributionMultilayer coil-coated steel sheets - Polymerphysical characterization and structure/property-relationships
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Lang, Reinhold, Assessor A (internal)
  • Buchmayr, Bruno, Assessor B (internal)
Publication statusPublished - 2008

Bibliographical note

embargoed until null

Keywords

  • coil coating topography appearance clear coating pre-coated metal (PCM) pre-coated steel sheet automotive body parts deformation dynamic-mechanical analysis (DMA) pigmentation thermoset coatings Polymerphysical characterization structure/property-relationships mirror-surface model

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