Patent ID: 6984717

Claim:
A process for preparing a phosphorus-containing polymer precursor which polymer precursor is substantially halogen-free and is a radiation-curable polyester, the process comprising the steps of (a) mixing together: (i) a compound containing at least one hydrocarbylidenically unsaturated group and a plurality of carbonyloxy groups; (ii) optionally a compound having a plurality of carbonyloxy groups and optionally free of hydrocarbylidenically unsaturated groups, (iii) a polyol, and (iv) an oxyphosphorous-containing compound (component (iv)) in which the phosphorous atom has at least one P—C bond which is resistant to hydrolysis or transesterification under the reaction conditions herein; such component (iv) comprising compounds of formula (I) and/or (II) and/or effective isomers, salts and mixtures thereof: R 1 R 2 R 3 P═O where, in formula (I): at least R 1 and R 2 independently represents C 1-20 organo group substituted by one or more hydroxy and/or carboxy group; R 3 represents H or optionally substituted C 1-20 organo group; in formula (II): the phosphorous atom is substituted with at least one carbon atom to form at least one P—C bond; the P—O bond forms part of an organo ring, the ring being optionally substituted with one or more organo groups and/or optionally fused to one or more other organo rings; (b) initiating polymerisation of the mixture to form a hydroxy and/or carboxy terminated phosphorous containing polyester oligomer (“First Polymer”), (c) reacting the First Polymer with at least one acrylating agent to form a radiation-curable polymer precursor (“Second Polymer”).