Process for preparing a silicate-pyrophosphate detergent composition

Claim 1

A process for preparing a detergent composition comprising: a. acidifying an aqueous alkali metal silicate with acid, during agitation, thereby forming a silicate premix; wherein the alkali metal silicate has the formula ρ M 2 O.SiO 2 , where M is alkali metal and ρ, the ratio of (mols M 2 O) to (mols SiO 2 ), is from about 0.25 to about 0.50; and wherein the amount of acid, expressed as a ratio of (equivalents of acid) to (mols SiO 2 in the silicate), is between about 0.0005 and about 0.4; b. mixing said silicate premix with an aqueous slurry comprised of surfactant, water, and at least one structurant, i.e. structure-forming compound, thereby forming a crutcher mix; wherein the surfactant is anionic, nonionic, semi-polar, zwitterionic, ampholytic, or mixtures thereof; and wherein the structurant is selected from the group consisting of calcium carbonate; natural and synthetic clays; nitrilotriacetates; aluminosilicates; and alkali metal pyrophosphates, triphosphates, glassy phosphates, carbonates, bicarbonates, sesquicarbonates, chlorides, borates, perborates, sulfates, bisulfates, aluminates, and mixtures thereof; c. drying said crutcher mix to a moisture of from about 0.5% to about 15% by weight of the dried crutcher mix; and d. adding admixed adjuvant to said dried crutcher mix, thereby forming said detergent composition; wherein the admixed adjuvant is selected from the group consisting of calcium carbonate; sodium aluminosilicates; alkali metal pyrophosphates, carbonates, borates, bicarbonates and sulfates; water-soluble aminopolycarboxylates; water-soluble salts of phytic acid; water-soluble polyphosphonates; and water-soluble salts of mellitic acid, citric acid, pyromellitic acid, benzene pentacarboxylic acid, oxydiacetic acid, carboxymethyloxysuccinic acid, and oxydisuccinic acid; wherein percentages of the components by weight, expressed in relation to the final detergent composition, are: SiO 2 in the silicate from about 1.5% to about 16%; surfactant from about 4% to about 50%; structurant from about 4% to about 90%; and admixed adjuvant from 0 to about 80%; and wherein alkali metal pyrophosphate, M x H y P 2 O 7 , where M is alkali metal and x and y are integers having the sum of 4, is present in the composition in an amount from about 5% to about 60%, said pyrophosphate being present as either structurant or admixed adjuvant or both.