Method for increasing the molecular weight of polyester resins
AssigneeMinistero Dell'Universita' e Della Ricerca Scientifica e Tecnologica
InventorsGabriele Perego, Catia Bastioli, Gian Domenico Cella, Andrea Gardano
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Abstract
A method for increasing the molecular weight of aliphatic polyester resins from dicarboxylic aliphatic acids having 2-22 carbon atoms, or from hydroxy-acids having 2-22 carbon atoms, in which the solid resin is brought into contact with a chain extender preferably chosen from the organic disocyaciates.
Claims11
A method for increasing the molecular weight of polyester resins having terminal hydroxyl groups and selected from the group consisting of aliphatic polyesters, aliphatic-aromatic copolyesters, polyester-amides, polyester-ether-amides, urethane polyesters and carbamide polyesters, wherein said resins are derived from aliphatic dicarboxylic acids having 2 to 22 carbon atoms and aliphatic, aromatic or cyclo-aliphatic diols having 2 to 22 carbon atoms, or from aliphatic hydroxy-acids having 2 to 22 atoms, or from the corresponding lactones or lactides,
- comprising contacting said resin in its solid state with an aliphatic or aromatic diisocyanate or a polyisocyanate and reacting the resin at room temperature or at a temperature lower than its melting point and not higher than the melting point of poly(1,10-decandiol-decandionate), said di or polyisocyanate being used in a sufficient quantity and being reacted for a sufficient time to obtain an increase in molecular weight corresponding to at least 0.1 dl/g unit of the intrinsic viscosity of the starting resin.
Dependencies are inferred from the claim text.