US 12,146,074 B2
Dispersant and waterborne epoxy coating composition
Weijun Yang, Shanghai (CN); Hu Li, Shanghai (CN); and Longlan Cui, Shanghai (CN)
Assigned to Dow Global Technologies LLC, Midland, MI (US)
Appl. No. 17/285,150
Filed by Dow Global Technologies LLC, Midland, MI (US)
PCT Filed Dec. 3, 2018, PCT No. PCT/CN2018/118894
§ 371(c)(1), (2) Date Apr. 14, 2021,
PCT Pub. No. WO2020/113366, PCT Pub. Date Jun. 11, 2020.
Prior Publication US 2021/0363363 A1, Nov. 25, 2021
Int. Cl. C08K 3/013 (2018.01); C08F 212/08 (2006.01); C08F 220/14 (2006.01); C08F 220/28 (2006.01); C08F 220/56 (2006.01); C08F 220/58 (2006.01); C08F 230/02 (2006.01); C09D 5/08 (2006.01); C09D 7/65 (2018.01); C09D 163/00 (2006.01)
CPC C09D 7/65 (2018.01) [C08F 212/08 (2013.01); C08F 220/14 (2013.01); C08F 220/286 (2020.02); C08F 220/56 (2013.01); C08F 220/585 (2020.02); C08F 230/02 (2013.01); C08K 3/013 (2018.01); C09D 5/08 (2013.01); C09D 163/00 (2013.01)] 13 Claims
 
1. A two-component epoxy coating composition comprising: an epoxy component A and a component B comprising a curing agent, wherein the epoxy component A comprises
(i) a waterborne epoxy resin,
(ii) a polymeric dispersant comprising, by weight based on the dry weight of the polymeric dispersant,
(a) from 11% to 60% of structural units of an acid monomer and/or a salt thereof selected from the group consisting of an ethylenically unsaturated sulfonic acid-containing monomer or a salt thereof, an ethylenically unsaturated phosphorous acid-containing monomer or a salt thereof, or mixtures thereof;
(b) from 0.5% to 20% of structural units of a carbonyl-containing functional monomer which is diacetone acrylamide; and
(c) from 20% to 88.5% of structural units of an ethylenically unsaturated nonionic monomer;
wherein the polymeric dispersant has a weight average molecular weight of from 300 to 40,000 Daltons, and
(iii) pigments and/or extenders
wherein the coating composition is characterized that when applied to a corrosion susceptible substrate at a dry film thickness of 50-60 μm it forms a coating having a blister rating better than “2MD” after at least 110 hours of exposure to salt spray.