| 摘要 |
The present invention concerns an aqueous powder coating dispersion based on epoxy resins and phenolic hardeners or carboxyl group-containing polyesters for coating packing containers. The powder coating dispersion comprises a solid powdery component (I) and an aqueous component (II), component (I) being a powder coating: 1) which comprises: A) at least one epoxy resin having an epoxide equivalent weight of between 300 and 5500; and B) at least one hardener having more than one phenolic hydroxyl group per molecule and a hydroxyl equivalent weight, relative to the phenolic OH groups, of between 100 and 500, preferably between 200 and 300; or C) at least one polyester with an acid number of between 25 and 120 mg KOH/g and an OH number of more than 10 mg KOH/g; and D) at least one epoxy resin with an epoxide equivalent weight of between 400 and 3000; and which 2) optionally comprises catalysts, auxiliary aids and additives typical of powder coatings, such as degassing agents, levelling agents, scavengers and antioxidants. Component (II) is the aqueous portion of the dispersion and contains: a) at least one non-ionic or anionic thickener, the non-ionic thickener preferably being a non-ionic associative thickener; and b) optionally catalysts, auxiliary aids, antifoaming agents, wetting agents, auxiliary dispersion aids, preferably carboxyl groupcontaining dispersants, antioxidants, biocides, small amounts of solvent, levelling agents, neutralizing agents, preferably amines and/or waterretention agents.
|
