Water based primer compositions

A primer composition for a metal surface comprising:

• an aqueous dispersion of
• (i) at least one epoxy resin;
• (ii) at least one organosilane, each said organosilane containing at least one hydrolyzable group;
• and
• (iii) a curing agent, solid at room temperature and active at a cure temperature between 60° C. and 200° C.,
• said primer composition curing at the cure temperature to enhance the adhesion of said metal surface to a polymeric adhesive.

A cured primer composition for a metal surface prepared by mixing:

• (i) at least one epoxy resin;
• (ii) at least one organosilane, each said organosilane containing at least one hydrolyzable group;
• and
• (iii) a curing agent solid at room temperature and active at a cure temperature between 60° C. and 200° C.;
• and curing at a temperature between 60° C. and 200° C., said cured primer composition having functional groups enhancing adhesion of said metal surface to a polymeric adhesive.

A bondable metal structure comprising at least two metal surfaces bondable to one another at an interface, comprising:

• (a) a primer coating on each of the metal surfaces, each primer coating comprising an aqueous dispersion of:
• (i) at least one thermosetting resin;
• (ii) at least one organosilane, each said organosilane containing at least one hydrolyzable group;
• and (iii) a curing agent solid at room temperature and active at a cure temperature between 60° C. and 200° C., each said primer coating cured at a temperature between 60° C. and 200° C.;
• and
• (b) a thermosetting adhesive between the primer coatings such that upon curing of the thermosetting adhesive the primer coating is capable of bonding with the metal surfaces and the thermosetting adhesive to form a strong and corrosion-resistant joint between the metal surfaces.

A primer composition comprising an aqueous dispersion of

• (A)(a) a dispersed phase from about 60 to about 10 percent by weight of said aqueous dispersion and (b) an aqueous continuous phase from about 40 to about 90 percent by weight of said aqueous dispersion, paid dispersed phase comprising a mixture of epoxy resins comprising:
• (i) from about 40 to about 70 weight percent of a solid epoxy resin having an epoxy functionality of from 1.8 to 4 and an epoxy equivalent weight of from about 400 to about 800;
• (ii) from about 5 to about 20 weight percent of a solid epoxy resin having an epoxy functionality of from 1.8 to 4 and an epoxy equivalent weight of from about 2000 to about 8000;
• (iii) from about 5 to about 40 weight percent of a solid epoxy resin having an epoxy functionality of at least 5 and having an epoxy equivalent weight of from about 100 to about 400;
• and
• said weight percents of said (i) to (iii) totaling 100 percent based on total weight of the epoxy component;
• (B) at least one organosilane, each said organosilane containing at least one hydrolyzable group, said organosilane is selected from the group consisting of beta-(3,4-epoxycyclohexyl) ethyl trimethoxysilane, gamma-glycidoxypropyl trimethoxysilane, gamma-mercaptopropyltrimethoxy silane, gamma-aminopropyltriethoxysilane, bis-(gammatrimethoxysilylpropyl)amine, N-phenyl-gammaamino-propyltrimethoxysilane, and (3-glycidoxypropyl)methyl-diethoxysilane;
• and
• (C) an aromatic curing agent selected from the group consisting of 2,2-bis(4-[4-aminophenoxy]-phenyl)propane, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenyl ketone, and 4,4′-[1,4-phenylene(1-methylethylidene)]bis(benzeneamine).