Water-based physically drying coating agents, manufacture and use thereof

A physically drying water-based coating composition containing:

• 8 to 30 wt. % of a binder composition comprising a mixture of components A) and B) wherein said components are:
• A) 10 to 90 wt. % of at least one polyurethane containing carbonate groups and having a number average molecular weight of 70,000 to 500,000, in the form of an aqueous dispersion, and
• B) 90 to 10 wt. % of a polyurethane containing carboxylic acid ester groups and having a number average molecular weight of 20,000 to 100,000, in the form of an aqueous dispersion,
• wherein the percentages by weight of the binder components A) and B) are based on binder solids and add to 100 wt. %, and wherein the number average molecular weights of components A) and B) are different such that the number average molecular weight of Component A) is greater than the number average molecular weight of Component B),
• C) 50 to 85 wt. % water,
• D) 1 to 20 wt. % of a solvent,
• E) 0.3 to 4 wt. % of a metallic pigment,
• F) 0 to 10 wt. % of a colouring pigment, and
• G) a neutralization agent in an amount sufficient to produce a neutralization degree of 40 to 120% in the neutralizable groups of the binder composition,
• wherein said component A) of the binder composition being obtained by reaction of:
• a) 10 to 40 wt. % of an organic polyisocyanate component characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups,
• b) 40 to 80 wt. % of a high-molecular weight organic polyhydroxyl compound characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups and comprising at least 50 wt. % polyhydroxyl polycarbonate,
• c) 0 to 18 wt. % of water or a low-molecular weight compound containing at least two groups capable of reacting with isocyanate groups and characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups,
• d) 0 to 8 wt. % of a non-ionic hydrophilic compound containing at least one isocyanate group or at least one group capable of reacting with isocyanate groups, and
• e) 1 to 12 wt. % of a compound containing at least one ionic group or at least one group convertible into an ionic group and at least one hydrogen atom capable of reacting with isocyanate groups,
• and wherein said component B) of the binder composition being obtained by reaction of:
• f) 10 to 40 wt. % of an organic polyisocyanate characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups,
• g) 40 to 80 wt. % of a high-molecular weight organic polyhydroxyl compound characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups,
• h) 0 to 18 wt. % of water or a low-molecular weight compound containing at least two groups capable of reacting with isocyanate groups and characterized by the absence of hydrophilic groups or groups convertible into hydrophilic groups,
• i) 0 to 8 wt. % of a non-ionic hydrophilic compound containing an isocyanate group or a group capable of reacting with isocyanate groups, and
• j) 1 to 12 wt. % of a compound containing at least one ionic group or at least one group convertible into an ionic group and at least one hydrogen atom capable of reacting with isocyanate groups,
• wherein said physically drying water-based coating composition is curable at about 20.degree. to 60.degree. C.