Patent ID: 6899924

Claim:
An intermediate layer composition for applying over a cured primer coated substrate, which intermediate layer composition comprises a film-forming synthetic resin, characterized in that the intermediate layer composition contains a non-volatile acidic aromatic polar organic compound in free acid or salt form, wherein the intermediate layer composition comprises the non-volatile acidic aromatic polar organic compound in free acid or salt form when cured, and with the proviso that when the non-volatile acidic aromatic polar organic compound contains at least one sulfonic acid group, the compound containing at least one sulfonic acid group is present in an amount greater than 0.05% by weight of the total weight of the cured intermediate layer composition, and characterized in that the synthetic resin has functional groups whereby it is curable and the intermediate layer composition contains a curing agent for crosslinking the synthetic resin, wherein the synthetic resin and curing agent are characterized by at least one of the following: the synthetic resin is an epoxy resin and the curing agent contains carboxylic acid groups; the synthetic resin contains amine or carboxylic acid groups and the curing agent contains epoxide groups; the synthetic resin contains hydroxyl groups and the curing agent contains blocked or unblocked isocyanate groups; the synthetic resin contains blocked or unblocked isocyanate groups and the curing agent contains hydroxyl groups; the synthetic resin contains activated —CH— groups bonded to at least two electron withdrawing groups and the curing agent contains blocked or unblocked amine groups, epoxide groups or, acrylic or methacrylic groups; the synthetic resin contains blocked or unblocked amine groups, epoxide groups or, acrylic or methacrylic groups and the synthetic resin contains activated —CH— groups bonded to at least two electron withdrawing groups; the synthetic resin contains anhydride groups and the curing agent contains hydroxyl groups; and the synthetic resin hydroxyl groups and the curing agent contains anhydride groups.