Polyurethane powder lacquers modified with fluorine compounds
Polimery 2012, No 11/12, 830
Polyisocyanates, used as crosslinking agents in powder lacquers, were synthesized in the reaction of diisocyanates, formic acid, fluorinated alcohols and imidazole. The structure of polyisocyanates was confirmed using IR, 1H NMR, 13C NMR and 19F NMR spectroscopy and the molecular weight distribution (MWD) was determined by gel permeation chromatography (GPC). The course of the unblocking and curing reactions was investigated by differential scanning calorimetry (DSC) and thermal analysis (DTA and TG). The prepared lacquer coatings containing fluorine exhibit higher values of contact angle for water, formamide and diiodomethane as well as lower surface free energy parameters compared to unmodified coatings. They also show improved application properties such as impact resistance, hardness, adhesion to steel surface and abrasion resistance.