Water-based composition with chemical cross-linking

A single-component sealant or adhesive composition, comprising:

• a) an aqueous polymer dispersion comprising water and at least one water-dispersed polymer P,
• b) at least one water-dispersed or water-dissolved isocyanate-functional cross-linker C with a nominal isocyanate-functionality of at least 2, and
• c) an aldimine of formula (I)
• where A is the rest of an amine after removal of n primary amino groups and m HX groups;
• n is 1 or 2 or 3 or 4;
• m is 0 or 1 or 2 or 3 or 4, with the provision that m+n is 2 or 3 or 4;
• R1 and R2 are either each independently a monovalent hydrocarbon radical with 1 to 12 C atoms or together form a divalent hydrocarbon radical with 4 to 12 C atoms that is part of an optionally substituted carbocyclic ring with 5 to 8 C atoms;
• R3 is a hydrogen atom or an alkyl-, cycloalkyl-, arylalkyl-, or alkoxycarbonyl radical with 1 to 12 C atoms;
• R4 is a hydrogen atom or a monovalent radical with 1 to 20 C atoms selected from alkyl-, cycloalkyl-, arylalkyl-, aryl-, —OR5′, —SR5′, and —NR5′R5″, wherein R5′ and R5″ either each independently are hydrocarbon radicals or together form an alkylene radical that is part of a 5-, 6-, or 7-membered ring;
• and X is O or S or NR6, wherein R6 is a hydrocarbon radical with 1 to 20 C atoms which is optionally substituted with a carbonic acid ester-, nitrile-, nitro-, phosphonic acid ester-, sulphone-, or sulphonic acid ester-group,
• wherein the at least one water-dispersed polymer P has functional groups selected from carboxylic acid groups, amino groups, and hydroxyl groups, and
• wherein the isocyanate-functional cross-linker C is a polyurethane polymer containing isocyanate groups having a number average molecular weight in a range of 2,000 to 15,000 g/mol, and
• wherein the composition comprises between 0.1 and 50 parts by weight of the isocyanate-functional cross-linker C per 100 parts by weight of the at least one water-dispersed polymer P.