1997 Volume 83 Issue 12 Pages 791-796
Structures of polyester films having high melamine-formaldehyde resin (MF) concentration in the surface were investegated by X-ray photoelectron spectroscopy, Fourier transformation infrared spectroscopy, and high frequency grow discharge spectroscopy. In films in which methylated MF enriched in the surface, MF concentration had a gradient from the surface to the interface with primer film. This structure of the film gave excellent stain resistance and excellent formability because of high MF concentration in the surface and low MF concentration in the bulk of the film. A mechanism proposed in the previous paper seemed correct from the film structure. In films in which butylated MF enriched in the surface, MF concentration was very high only in the surface of the film and constant in the bulk. This structure gave excellent stain resistance because of high surface MF concentration, but not so good formability. Butylated MF seemed to be enriched in the surface of the film because of low surface tension compared with that of polyester resin or solvents in paints. In combination of methylated MF and non-neutralized catalyst, the film had uniform MF concentration through the depth. This film didn't show good formability and stain resistance because of both low surface concentration of MF resin and uniform concentration of MF resin in the bulk.
