4740314 Anionic polymers containing N-vinyl-2-pyrrolidone or other vinyl amides and maleic anhydride or maleic acid as scale inhibitors for preventing or reducing calcium phosphate and other scales

Abstract

A method of inhibiting scale, generally and specifically and preferably calcium phosphate and calcium carbonate scale, which is found on metal surfaces in contact with industrial cooling waters, boiler waters, oil well drilling waters, and evaporated sea water, which comprises treating the water present in such systems with a few ppm of a water-soluble maleic anhydride or acid co- or terpolymer of N-vinyl-2-pyrrolidone (NVP) or vinyl amide.