Patent ID: 8481473

Claim:
A detergent concentrate comprising: (a) an alkalinity source consisting of an alkali metal hydroxide constituting between about 1% and about 75% by weight of the detergent concentrate; (b) a nonionic surfactant system constituting between about 0.05% and about 25% by weight of the detergent concentrate; (c) a threshold system constituting between about 0.0005% and about 30% by weight of the detergent concentrate; wherein the threshold system comprises a sulfonate/acrylate copolymer consisting essentially of a copolymer of acrylic acid and 2-acrylamido-2-methylpropane sulfonic acid, an acrylate homopolymer and a phosphonoalkane carboxylic acid, wherein the phosphonalkane carboxylic acid constitutes between about 5% to about 30% by weight of the threshold system, wherein the threshold system has a sulfonate/acrylate copolymer to acrylate homopolymer weight ratio of between about 2:1 and about 1:2 and has an acrylate homopolymer to phosphonoalkane carboxylic acid weight ratio of between about 4:1 and 1:1; and wherein the concentrated detergent concentrate is in the form of a cast solid block: and further wherein the detergent concentrate when diluted with water to form a use solution has a pH of greater than 10.