Coating material used as clearcoat for painting cars has a binder-crosslinker system containing a carboxy-functional acrylic copolymer or polyester and a branched, epoxide-functional acrylic copolymer

摘要

Branched, epoxide-functional (meth)acrylic copolymers with a calculated branching equivalent wt. of 5000-60000 g/mol are used in binder/crosslinker systems for coating materials, together with carboxy-functional (meth)acrylic polymers and optionally other polymer-polyols, crosslinkers and/or epoxides. Coating material with a binder/crosslinker system, organic solvent and/or water and optionally pigments and/or fillers and/or other normal paint additives, in which the binder/crosslinker system contains (A) 20-80 wt% carboxy-functional (meth)acrylic copolymer and/or polyester, optionally urethanized or modified with lactone, with a functionality corresponding to an acid number of 15-300 mg KOH/g, (B) 80-20 wt% epoxide-functional (meth)acrylic copolymer with a calculated epoxide equiv. wt. of 200-700 g/mol (the total amount of A and B is 100 wt% and the crosslink ratio between COOH groups in A and epoxide groups in B is (1:1)-(1;3)), (C) 0-30 wt% (based on solids in A + B) polymer-polyols other than (A and B), (D) 0-20 wt% (based on A + B + C) additional crosslinker(s) other than (A, B and C), and (E) 0-10 wt% (based on solids in A + B) poly- and/or mono-epoxide(s) other than (B). The epoxide-functional copolymers (B) have a branched structure, corresponding to a calculated branching equiv. wt. of 5000-60000 g/mol. An Independent claim is also included for a multi-layer painting process involving the application of a colored and/or special effect basecoat to an optionally precoated substrate followed by application of the above coating material as a clearcoat.