Aqueous basecoat composition comprising a silane-based additive and having improved adhesion properties and multilayer coatings produced from said basecoat compositions

An aqueous coating composition comprising:

• a) at least one silane-based compound R having an isocyanate content of less than 1 mol % obtained by reacting free isocyanate groups of at least one aliphatic, cycloaliphatic, araliphatic and aromatic polyisocyanate with at least one silane compound of general formula (I)
• HN
• [
• X
• -
• SiR
• a
• 1
• (
• OR
• 2
• )
• 3
• -
• a
• ]
• n
• [
• X
• ′
• -
• SiR
• b
• 1
• (
• O
• ⁢
• R
• 2
• )
• 3
• -
• b
• ]
• m
• [
• R
• 3
• ]
• 2
• -
• (
• m
• +
• n
• )
• (
• I
• )
• wherein
• X, X′ represent, independently from each other, linear and/or branched alkylene or cycloalkylene radicals having 1 to 20 carbon atoms;
• R1 represents an alkyl, cycloalkyl, aryl, or aralkyl group, it being possible for the carbon chain of the alkyl, cycloalkyl, aryl, or aralkyl groups to be interrupted by nonadjacent oxygen, sulfur, or NRa groups, where Ra is alkyl, cycloalkyl, aryl, or aralkyl;
• R2 represents hydrogen, an alkyl, or a cycloalkyl group, it being possible for the carbon chain of the alkyl, cycloalkyl, aryl, or aralkyl groups to be interrupted by nonadjacent oxygen, sulfur or NRa groups, where Ra is alkyl, cycloalkyl, aryl, or aralkyl;
• R3 represents a linear and/or branched alkylene or cycloalkylene radicals having 1 to 20 carbon atoms;
• n, m being, independently from each other, 1 or n being 1 and m being 0;
• and
• a, b being, independently from each other 0 to 2;
• and
• b) at least one binder B being different from the silane-based compound of general formula (I);
• and
• c) at least one pigment P.