EFFECTS OF PAINT COMPOSITION AND CONDITIO NS FOR MAKING FILMS ON MELAMINE RESIN CONCENTRATION IN THE SURFACE OF POLYESTER FILMS

In polyester resin films cured by melamine-formaldehyde resin (MF), MF concentration in the surface of films was measured by X-ray photoelec tron spectroscopy (XPS). The MF concentration in the surface increased as the following parameters increased; MF concentration in paints, ca talyst concentration, baking temperature (peak metal pemperature), and film thickness. Performance of the prepainted steel sheets having MF enriched films were also evaluated. Stain resistance and T-bend abilit y of prepaited steel sheets improved with increasing MF concentration in the surface of the films. MF enriched films were found to have both excellent formability and stain resistance.