| 摘要 |
The invention concerns a linear or branched polyurethane resin based on a polyester, obtained from A) a hydroxylated fatty polyester, with: - said polyester A) being the reaction product of a) an alcohol component with b) an acid component, said acid component b) comprises b1) at least one fatty acid, with said component b) also comprising b2) rosin and/or rosin derivatives bearing at least one carboxylic acid function, b2) representing between 30 and 85% by weight relative to the total weight of A) - optionally, said polyester A) having an oil length of zero (0%) or between 0 and 60%, - optionally, said polyester A) having a weight ratio of oxidisable fatty acids (monoacids) relative to the fatty acids of 0 or greater than 0 and up to 1, and with said resin being the reaction of said polyol polyester A) with: B) at least one diol comprising an acid function with said acid function being optionally neutralised C) at least one polyisocyanate with a functionality of between 2 and 3. The polyurethane resin of the invention based on biosourced polyester is used as a binder in coatings and, in particular, in aqueous dispersions for 20 aqueous coatings with specific performances in terms of speed of drying, development of hardness over time in the absence of a drying agent during drying, and resistance to yellowing and water. |
