Abstract: Described herein is an aqueous basecoat composition including a silane-based additive as hardener/self-crosslinking material to improve adhesion of the basecoat to the under—and overlying coating layers, as well as the cohesion property of the basecoat itself. Also described herein is a mixer system for preparing an aqueous refinish basecoat composition including at least one base color component, at least one pigment-free component, at least one hardening component including the silane-based additive and optionally at least one rheology module as well as a method to prepare an aqueous basecoat composition from said mixer system. Further, described herein is a method of coating a substrate with the basecoat composition and a clearcoat composition and jointly curing the basecoat and clearcoat composition as well as to a coated substrate obtained from the method. Finally, described herein is a method of using the silane-based compound as hardening additive in aqueous basecoat compositions.

Abstract: Disclosed herein is a silane-functional hardener for carboxyl-functional resins including at least one monomer and/or oligomer and/or polymer having at least one group represented by Formula I-(a) and/or Formula I-(b) and at least one group represented by Formula II-(a) and/or Formula II-(b): where, R1, R2 and R3 independently represent a C1-C18 alkyl group, C1-C6 alkoxyl group, phenyl group, aryl group, hydrogen atom, chlorine atom or fluorine atom and at least one of R1, R2 and R3 is a C1-C6 alkoxyl group, R4 represents a C1-C18 alkyl group, C1-C6 alkanol group, C1-C6 alkoxyl group, or hydrogen atom, R5 represents a hydrogen atom, C1-C18 alkyl group, or C1-C6 alkoxyl group, R6 represents a C2-C6 acyl group, C1-C18 alkylene group or arylene group and R7 represents a —NR4— group, C2-C6 acyl group, C1-C18 alkylene group, C1-C18 alkoxy group or arylene group.

Abstract: Described herein is a curable coating composition including at least one Michael donor (A) having at least one acetoacetate group, at least one Michael acceptor (B) and at least one specific catalyst (C). Also described herein are a method of using the curable coating composition as a clear coating in a method to prepare a multilayer coating and a multilayer coating obtained from said process. Further described herein is a kit-of-parts including at least two separate containers C1 and C2, where the specific catalyst (C) and/or the at least one Michael acceptor (B) is contained in container C2. Additionally described herein is a method of using specific salts of carboxylic acids as catalyst in a reaction between a Michael donor (A) having at least one acetoacetate group and a Michael acceptor (B).