Patent ID: 7611787

Claim:
An ion exchange resin comprising at least 15% by total number of exchangeable groups comprising at least one of an ion, a Lewis acid, or a Lewis base resulting from a colorant having a pK a or pK b of greater than 5 in an aqueous solution at 25° C., based on the total number of exchangeable groups; and wherein the colorant is of the formula: R{A k [(B) n R 1 ] m } x wherein R is an organic chromophore selected from the group consisting of anthraquinone, triphenylmethane, diphenylmethane, azo containing compounds, disazo containing compounds, trisazo containing compounds, diazo containing compounds, xanthene, acridine, indene, phthalocyanine, azaannulene, nitroso, nitro, diarylmethane, triarylmethane, methine, indamine, azine, oxazine, thiazine, quinoline, indigoid, indophenol, lactone, aminoketone, hydroxyketone, stilbene, thiazole, one or more conjugated aromatic groups, one or more conjugated heterocyclic groups, one or more conjugated C—C double bonds, and combinations thereof; A is a linking moiety in said chromophore and is selected from the group consisting of O, N and S; k is 0 or 1; B is selected from the group consisting of one or more alkyleneoxy or alkoxy groups containing from 1 to 8 carbon atoms; n is an integer of from 1 to 100; m is 1 or 2; x is an integer of from 1 to 5; and R 1 is selected from the group consisting of H, C 1 -C 6 alkyl or alkoxy groups containing from 1 to 8 carbon atoms, and combinations thereof.