| abstract |
Proposed is a thermosetting powder coating composition comprising a mixture of particles reactive towards one another and a catalyst, with a portion of the reactive particles comprising a polymer reacting with epoxy to form ester forming or ether forming groups, while another portion comprises an at least bifunctional cross-linking agent which contains 2-oxo-1,3-dioxolan-4-yl groups, hereinafter referred to as cyclocarbonate groups, and, optionally, epoxy groups, with both the polymer reacting with epoxy to form ester forming and/or ether forming groups and the cross-linking agent being obtained by means of a non-vinylic addition and/or polymerisation process. The catalyst used as ring opener for the cyclocarbonate groups is present in a quantity of 0,01 to 10, preferably 0,1 to 5, parts by weight per 100 parts by weight of the mixture of particles reactive towards one another. The quantity of epoxy oxygen present in the cross-linking agent after CO2 unblocking preferably is at least 0,4 wt.%. The reactive polymer preferably is a polymer containing groups reactive towards epoxy such as carboxyl, anhydride and/or hydroxyl groups, with preference being given to polyesters and/or polyurethanes. |