Thermosetting compositions containing epoxy functional polymers prepared by atom transfer radical polymerization

A multi-component composite coating composition comprising:

• (a) a base coat deposited from a pigmented film-forming composition;
• and
• (b) a transparent top coat applied over said base coat, wherein said transparent top coat is deposited from a clear film-forming thermosetting composition comprising a co-reactable solid, particulate mixture of:
• (i) an epoxy functional polymer prepared by atom transfer radical polymerization initiated in the presence of an initiator having at least one radically transferable group, and in which said epoxy functional polymer contains at least one of the following polymer chain structures:
• Φ-[-(M)p-(G)q]x-T
• or
• Φ-[-(G)q-(M)p]x-T
• wherein M is a residue, that is free of oxirane functionality, of at least one ethylenically unsaturated radically polymerizable monomer;
• G is a residue, that has oxirane functionality, of at least one ethylenically unsaturated radically polymerizable monomer;
• Φ is a residue from the initiator, free from the radically transferable group, selected from the group consisting of linear or branched aliphatic compounds, cycloaliphatic compounds, heterocyclic compounds, sulfonyl compounds, sulfenyl compounds, esters of carboxylic acids, polymeric compounds and mixtures thereof;
• T is or is derived from the radically transferable group and is selected from the group consisting of halide and a dehalogenation post-reaction of a limited radically polymerizable ethylenically unsaturated compound;
• p and q represent average numbers of residues occuring in a block of residues in each polymer chain structure;
• p, q and x are each individually selected for each structure such that said epoxy functional polymer has a number average molecular weight of at least 250;
• p is an integer of from 1 to less than 100;
• q is an integer of from 1 to less than 15;
• and x is an integer of from 1 to less than 10;
• and wherein the epoxy functional polymer has an epoxy equivalent weight of from at least 200 to less than 1,000 grams/equivalent;
• and
• (ii) co-reactant havin functional groups reactive with the epoxy groups of (i).