Process for preparation of phosphate esters of polymeric materials containing hydroxyl groups

Claim 1

A PROCESS FOR THE PRODUCTION OF PHOSPHATE ESTERS OF POLYMERIC MATERIALS CONTAINING HYDROXYL GROUPS WHICH COMPRISES THE STEPS OF HEATING A SUBSTANTIALLY EQUIMOLAR MIXTURE OF PHOSPHORIC ACID AND A UREA COMPOUND SELECTED FROM THE GROUP CONSISTING OF UREA, METHYL UREA, DIMETHYL UREA, ETHYL UREA AND PHENYL UREA IN A LIQUID, NON-AQUEOUS ORGANIC SOLVENT SELECTED FROM THE GROUP CONSISTING OF AROMATIC HYDROCARBONS, ALKANOLS HAVING FROM THREE TO EIGHT CARBON ATOMS, AND MIXTURES THEREOF, TO A TEMPERATURE SUFFICIENT TO REMOVE WATER THEREFROM FOR A PERIOD OF TIME SUFFICIENT TO REMOVE SUBSTANTIALLY ALL THE WATER PRESENT AND TO FORM A UREA PHOSPHATE SOLUTION, ADDING A POLYMERIC MATERIAL CONTAINING HYDROXYL GROUPS SELECTED FROM THE GROUP CONSISTING OF A POLYVINYL ALCOHOL AND WATERSOLUBLE ETHERS OF CELLULOSE SELECTED FROM THE GROUP CONSISTING OF METHYL CELLULOSE, ETHYL CELLULOSE AND HYDROXYETHYL CELLULOSE, TO FORM A NON-AQUEOUS SUSPENSION IN SAID UREA PHOSPHATE SOLUTION, HEATING SAID NON-AQUEOUS SUSPENSION AT A TEMPERATURE BETWEEN ABOUT 70*C. AND ABOUT 140*C. FOR A TIME SUFFICIENT TO EFFECT SUBSTANTIAL ESTERIFICATION OF SAID HYDROXYL GROUPS AND RECOVERING SAID PHOSPHATE ESTERS.