Method of making a reverse osmosis semipermeable membrane

Claim 1

A process of preparation of a semipermeable composite membrane comprising: (a) applying to the surface of a porous substrate an aqueous solution containing (A) at least one component selected from the group consisting of (i) a component defined by the Formula (I) or reaction products formed between a plurality of components of the formula: ##STR3## wherein each of R 1 , R 2 , and R 3 is selected from the group consisting of hydrogen, an alkyl radical containing from 2 to 5 carbon atoms, and an alkyl radical carrying a functional hydroxyl group or a functional glycidyl group, with the proviso that at least two of R 1 , R 2 , and R 3 comprise alkyl radicals carrying a functional hydroxyl group or a functional glycidyl group, (ii) reaction products between a compound defined as group (i) and at least one water soluble comonomer selected from the group consisting of furfuryl alcohol, tetrahydrofurfuryl alcohol, an epoxy compound containing from 2 to 5 carbon atoms, a multivalent alcohol containing from 2 to 8 carbon atoms, polyethylene oxide, a multivalent carboxylic acid containing from 2 to 17 carbon atoms, multivalent hydroxy acid containing from 2 to 17 carbon atoms and formaldehyde, and (iii) a mixture of reaction products between the compounds defined as group (i) and at least one water soluble comonomer selected from the group consisting of furfuryl alcohol, tetrahydrofurfuryl alcohol, an epoxy compound containing from 2 to 5 carbon atoms, a multivalent alcohol containing from 2 to 8 carbon atoms, polyethylene oxide, a multivalent carboxylic acid containing from 2 to 17 carbon atoms, a multivalent hydroxy acid containing from 2 to 17 carbon atoms and formaldehyde, and (B) an acid catalyst, and (b) heating the solution to polymerize the compound represented by the Formula (I) and/or said comonomer at a temperature of from about 100° C. to 190° C. for a period of about one minute to about 30 minutes.