Polyester

A polyester consisting of:

• A) repeat units derived from an acid component, which consists of
• a1) 30 to 90 mol %, based on the sum of components a1, a2, and a3, of 2,5-furandicarboxylic acid,
• a2) 0 to 60 mol %, based on the sum of components a1, a2, and a3, of an aliphatic C4-C36 dicarboxylic acid or a mixture of a plurality of aliphatic C4-C36 dicarboxylic acids, and
• a3) 10 to 60 mol %, based on the sum of components a1, a2, and a3, of a sulfonate group-containing dicarboxylic acid,
• wherein a3 is an aromatic sulfonate group-containing dicarboxylic acid in which the sulfonate group is present either as the free acid or as a salt, and a3 is selected from the group consisting of 1,4-benzenedicarboxylic acid-2-sulfonic acid, 1,3-benzenedicarboxylic acid-5-sulfonic acid, 1,2-benzenedicarboxylic acid-3-sulfonic acid, and 1,2-benzenedicarboxylic acid-4-sulfonic acid, in each case in the form of the free acid or of a salt, and
• wherein the molar percentages of components a1) to a3) together add up to 100 mol %,
• B) repeat units derived from a di-ol/amine component consisting of
• b1) a C2 to C12 alkanediol or a mixture of a plurality of C2 to C12 alkanediols, and/or
• b2) a dihydroxy compound of formula I,
• HO—[(CH2)n—O]m—H (I)
• where n is 2, 3 or 4 and m is an integer from 2 to 250,
• or a mixture of a plurality of such dihydroxy compounds,
• b3) optionally one or more amino C2 to C12 alkanols or one or more amino C5 to C10 cycloalkanols or mixtures thereof, and
• b4) optionally one or more diamino C1 to C8 alkanes,
• wherein the amount of B is chosen so that for every 100 mol of A there is 100 mol of B present, minus the number of moles of D and E,
• and wherein a sum of b1 and b2 in B is at least 50 mol %,
• C) optionally repeat units derived from
• c1) one or more hydroxycarboxylic acids of formula IIa,
• HO—C(O)-G-OH (IIa)
• where G represents a radical selected from the group consisting of phenylene, —(CH2)q—, in which q is an integer from 1 to 5, —C(R)H—, and —C(R)HCH2, in which R is methyl or ethyl, and/or
• c2) one or more aminocarboxylic acids or cyclic amides thereof selected from the group consisting of caprolactam, 1,6-aminocaproic acid, laurolactam, 1,12-aminolauric acid, and 1,11-aminoundecanoic acid,
• wherein the proportion of C in the total mass of the polyester is not more than 20% by weight,
• D) 0.1 to 4% by weight, based on the sum of components A, B, and C, of repeat units derived from at least one di- or oligofunctional compound selected from the group consisting of a di- or oligoisocyanate and a di- or oligoisocyanurate, and
• E) 0.1 to 4% by weight, based on the sum of components A, B, and C, of repeat units derived from a branching component that contains at least three functional groups, wherein the functional groups are selected from the group consisting of COOH, OH, NH2, and mixtures thereof.