| abstract |
The present invention relates to an organic binder resin for aqueous coatings, comprising: a) a polymer P1, carrying reactive groups X1: hydroxyl and Y1: carboxy with an OH index in% by weight OH ranging from 2 to 5% and an acid index IA mg KOH / g of at least 10, said polymer P1 having a mass Mn1 of less than 25,000, b) a polymer P2 carrying reactive groups X2: hydroxyls with an OH index in% by weight OH ranging from 0.5 to 2.5 %, of groups Y2: carboxy with an acid number IA in mg KOH / g <25 and of groups Z2 chosen from acetoxy and / or diacetone and said polymer P2 having a mass Mn2 greater than 500,000. The invention also relates to a process for the preparation of said resin, a metallic coating composition comprising in addition to said resin a metallic pigment and also its use in metallic coatings such as the resulting metallic coating. |