A combination comprising: - at least a polyester having a crystalline backbone and at least one end-capping group, wherein the end-capping group comprises any one of an ester, urethane, thiocarbamate or urea moiety connected either directly or by means of a spacer to a first crosslinkable group; - at least a compound comprising a second crosslinkable group; wherein the first and second crosslinkable groups are selected from either: - a thiol comprising group; or - an -ene group of formula, wherein ∘ R 1, R 2, R 3 are independently selected from: H, alkyl, O, N, halogen, S or at least one of R 1, R 2, R 3 together with the group at position X form a cyclic or heterocyclic structure; ∘ X is a group selected from: alkyl, O, N, S, (C=O)N, (C=O)alkyl, O-alkyl, N-alkyl, S-alkyl, and wherein at least one group of the first and second crosslinkable groups is the thiol comprising group and at least one group of the first and second crosslinkable groups is the -ene group of formula, and wherein the polyester and the compound comprise at least 2 of a first, respectively second crosslinkable groups, and the sum of said first, respectively second crosslinkable groups, is at least 5, and wherein the molar ratio of the first crosslinkable group to the second crosslinkable group is from 0.75 to 1.5, preferably from 0.8 to 1.2. - at least a polyester having a crystalline backbone and at least one end-capping group, wherein the end-capping group comprises any one of an ester, urethane, thiocarbamate or urea moiety connected either directly or by means of a spacer to a first crosslinkable group; - at least a compound comprising a second crosslinkable group; wherein the first and second crosslinkable groups are selected from either: - a thiol comprising group; or - an -ene group of formula, wherein ∘ R 1, R 2, R 3 are independently selected from: H, alkyl, O, N, halogen, S or at least one of R 1, R 2, R 3 together with the group at position X form a cyclic or heterocyclic structure; ∘ X is a group selected from: alkyl, O, N, S, (C=O)N, (C=O)alkyl, O-alkyl, N-alkyl, S-alkyl, and - a thiol comprising group; or - an -ene group of formula, wherein ∘ R 1, R 2, R 3 are independently selected from: H, alkyl, O, N, halogen, S or at least one of R 1, R 2, R 3 together with the group at position X form a cyclic or heterocyclic structure; ∘ X is a group selected from: alkyl, O, N, S, (C=O)N, (C=O)alkyl, O-alkyl, N-alkyl, S-alkyl, and ∘ R 1, R 2, R 3 are independently selected from: H, alkyl, O, N, halogen, S or at least one of R 1, R 2, R 3 together with the group at position X form a cyclic or heterocyclic structure; ∘ X is a group selected from: alkyl, O, N, S, (C=O)N, (C=O)alkyl, O-alkyl, N-alkyl, S-alkyl, and wherein at least one group of the first and second crosslinkable groups is the thiol comprising group and at least one group of the first and second crosslinkable groups is the -ene group of formula, and wherein the polyester and the compound comprise at least 2 of a first, respectively second crosslinkable groups, and the sum of said first, respectively second crosslinkable groups, is at least 5, and wherein the molar ratio of the first crosslinkable group to the second crosslinkable group is from 0.75 to 1.5, preferably from 0.8 to 1.2.