| 摘要 |
The invention concerns a method for preparing a hydroxylated or carboxylated polyester resin that is linear or branched and free of unsaturated fatty acid, said method comprising the reaction between an acid component a) and an alcohol component b), in which a) comprises a1) at least one C4 to C6 carboxylic polyacid or anhydride, a2) at least one C8 to C54 carboxylic polyacid or anhydride and a3) optionally, at least one C2 to C22 saturated monoacid and the alcohol component b) comprises b1) at least one biobased polyol having a functionality fb1 of at least 2, having a 1,4:3,6 dianhydrohexitol unit and at least one of the two following polyols b2) or b3): b2) at least one polyol different from b1) and having a functionality fb2 of at least 2 and b3) at least one polyol different from b1) and b2) having a functionality fb3 of at least 3, said reaction taking place according to the following series of steps: i) reacting the whole of the acid component a) with said component b1) of said alcohol component b) until conversion of at least 85 mol% of said component b1), followed by ii) reacting the product from step i), with the remainder of said alcohol component b), comprising at least one of said polyols b2) or b3), with the reactions of said steps i) and ii) taking place in solution in at least one organic solvent that can form an azeotrope with water. Said resin can be used for crosslinkable coatings. |
