Multi-part water-borne coating composition

A multi-part water-borne coating composition comprising:

• water;
• (I) a first part comprising:
• (a1) a core-shell latex copolymer having pendant hydroxyl and pendant carbonyl groups, said core-shell latex copolymer comprising a core copolymer and a shell copolymer disposed about said core polymer, each of said core copolymer and said shell copolymer independently comprising the residues of:
• i) at least one (meth)acrylate monomer represented by Formula MA:
• wherein:
• Ga is hydrogen, halogen or methyl;
• and,
• Ra is:
• C1-C18 alkyl;
• C2-C18 heteroalkyl;
• C3-C18 cycloalkyl;
• C2-C8 heterocycloalkyl;
• C2-C8 alkenyl;
• C2-C8 alkynyl;
• C6-C18 aryl, C1-C9 heteroaryl, C7-C18 alkoxyaryl, C7-C18 alkaryl or C7-C18 aralkyl;
• and,
• optionally ii) at least one vinyl aromatic monomer;
• optionally iii) at least one monomer having at least two ethylenically unsaturated groups and having a weight average molecular weight (Mw) of at most 600 Daltons;
• wherein at least one of the core copolymer and shell copolymer comprises the residues of:
• iv) at least one hydroxyl functional ethylenically unsaturated monomer;
• and,
• v) at least one carbonyl functional ethylenically unsaturated monomer;
• and,
• (II) a second part comprising:
• (b1) at least one polyisocyanate compound having pendant —NCO groups,
• wherein:
• the multi-part composition further comprises (c) at least one polyhydrazide compound having at least two hydrazide groups of the formula —C(═O)—NH—N(Rh)(Ri), wherein Rh and Ri are independently H or C1-C12 alkyl;
• constituent (c) is provided in (I) said first part and/or in (III) a third part of the composition;
• the molar ratio of hydroxyl groups to —NCO groups in the composition is from about 5:1 to about 1:5;
• and,
• the molar ratio of hydrazide groups to carbonyl groups in the composition is from about 5:1 to about 1:5.