Method of reducing corrosion using a warewashing composition

Abstract

A warewashing composition includes a cleaning agent having a detersive amount of a surfactant, an alkaline source in an amount effective to provide a use composition having a pH of at least about 8 when the use composition is measured at a solids concentration of about 0.5 wt %, and a corrosion inhibitor in an amount sufficient for reducing corrosion of glass when the warewashing composition is combined with water of dilution at a dilution ratio of at least about 20:1 water of dilution to detergent composition o form a use composition. The corrosion inhibitor includes a salt of calcium, magnesium, or a mixture of calcium and magnesium. The salt has a water solubility of less than about 0.5 wt % in water at about 20° C. and atmospheric pressure so that the salt precipitates to form a protective layer on a substrate in contact with the use composition.

1 . A warewashing composition comprising:
 (a) a cleaning agent comprising a detersive amount of a surfactant;   (b) an alkaline source in an amount effective to provide a use composition having a pH of at least about 8 when the use composition is measured at a solids concentration of about 0.5 wt %; and   (c) a corrosion inhibitor in an amount sufficient for reducing corrosion of a substrate when the warewashing composition is combined with a diluent at a dilution ratio of at least about 20:1 of diluent to warewashing composition to form a use composition, wherein the corrosion inhibitor comprises a salt of calcium, magnesium, or a mixture of calcium and magnesium, and wherein the salt has a water solubility of less than about 0.5 wt % in water at about 20° C. and atmospheric pressure so that the salt precipitates to form a protective layer on the substrate in contact with the use composition.   
     
     
         2 . The warewashing composition according to  claim 1 , wherein the cleaning agent constitutes from about 0.05 wt % to about 15 wt % of the warewashing composition. 
     
     
         3 . The warewashing composition according to  claim 1 , wherein the cleaning agent comprises at least one of an anionic surfactant, a nonionic surfactant, a cationic surfactant and a zwitterionic surfactant. 
     
     
         4 . The warewashing composition according to  claim 1 , wherein the corrosion inhibitor constitutes between about 0.01 wt % and about 15 wt % of the warewashing composition. 
     
     
         5 . The warewashing composition according to  claim 1 , wherein the warewashing composition comprises less than about 1 wt % phosphorus-containing compounds. 
     
     
         6 . The warewashing composition according to  claim 1 , further comprising builder, wherein the builder constitutes about 1 wt % to about 60 wt % of the warewashing composition and wherein the builder comprises a non-phosphorous containing builder. 
     
     
         7 . The warewashing composition according to  claim 1 , wherein the alkaline source constitutes between about 5 wt % and about 40 wt % of the warewashing composition. 
     
     
         8 . The warewashing composition according to  claim 1 , wherein the alkaline source comprises at least one of an alkali metal carbonate, an alkali metal hydroxide and a mixture thereof. 
     
     
         9 . The warewashing composition according to  claim 8 , wherein the alkaline source comprises at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium sesquicarbonate and potassium sesquicarbonate. 
     
     
         10 . The warewashing composition according to  claim 8 , wherein the alkaline source comprises at least one of sodium hydroxide and potassium hydroxide. 
     
     
         11 . The warewashing composition according to  claim 1 , wherein the salt comprises a water soluble magnesium salt selected from at least one of magnesium acetate, magnesium benzoate, magnesium bromide, magnesium bromate, magnesium chlorate, magnesium chloride, magnesium chromate, magnesium citrate, magnesium formate, magnesium hexafluorosilicate, magnesium iodate, magnesium iodide, magnesium lactate, magnesium molybdate, magnesium nitrate, magnesium perchlorate, magnesium phosphinate, magnesium salicylate, magnesium sulfate, magnesium sulfite, magnesium tartrate, magnesium thiosulfate, a hydrate thereof, and a mixture thereof. 
     
     
         12 . The warewashing composition according to  claim 1 , wherein the salt comprises a water insoluble magnesium salt selected from at least one of magnesium aluminate, magnesium borate, magnesium carbonate, magnesium carbonate hydroxide, magnesium ferrate, magnesium fluoride, magnesium hydroxide, magnesium mandelate, magnesium oxalate, magnesium oxide, magnesium phosphate, magnesium silicate, magnesium tungstate, a hydrate thereof, and a mixture thereof. 
     
     
         13 . The warewashing composition according to  claim 1 , wherein the salt comprises a water soluble calcium salt selected from at least one of calcium acetate, calcium benzoate, calcium bromate, calcium bromide, calcium chlorate, calcium chloride, calcium chromate, calcium dihydrogen phosphate, calcium dithionate, calcium formate, calcium gluconate, calcium glycerophosphate, calcium hydrogen sulfide, calcium iodide, calcium lactate, calcium metasilicate, calcium nitrate, calcium nitrite, calcium pantothenate, calcium perchlorate, calcium permanganate, calcium phosphate, calcium phosphinate, calcium salicylate, calcium succinate, a hydrate thereof, and a mixture thereof. 
     
     
         14 . The warewashing composition according to  claim 1 , wherein the salt comprises a water insoluble calcium salt selected from at least one of calcium aluminate, calcium carbonate, calcium chromium (III) oxide, calcium citrate, calcium diphosphate, calcium disilicide, calcium fluoride, calcium hydrogen phosphate, calcium hydroxide, calcium iron oxide, calcium iodate, calcium laurate, calcium magnesium carbonate, calcium magnesium silicon oxide, calcium malonate, calcium metaborate, calcium metaphosphate, calcium molybdate, calcium oleate, calcium oxalate, calcium oxide, calcium palmitate, calcium phosphate, calcium silicate, calcium silicon oxide, calcium silicon titanium oxide, calcium stearate, calcium sulfate, calcium sulfide, calcium sulfite, calcium tartrate, calcium titanate, calcium tungstate, a hydrate thereof, and a mixture thereof. 
     
     
         15 . The warewashing composition according to  claim 1 , wherein the use composition has a solids content of less than about 1 wt %. 
     
     
         16 . A method of cleaning an article and reducing corrosion to a surface of the article comprising:
 (a) providing a warewashing composition, wherein the warewashing composition comprises:
 (i) a cleaning agent, wherein the cleaning agent constitutes between about 0.05 wt % and about 15 wt % of the warewashing composition; 
 (ii) an alkaline source, wherein the alkaline source constitutes between about 5 wt % and about 40 wt % of the warewashing composition; and 
 (iii) a corrosion inhibitor, wherein the corrosion inhibitor constitutes between about 0.01 wt % and about 15 wt % of the warewashing composition, wherein the corrosion inhibitor comprises at least one of a water soluble magnesium salt, a water insoluble magnesium salt, a water soluble calcium salt and a water insoluble calcium salt; 
   (b) diluting the warewashing composition with a diluent to form an aqueous composition; and   (c) contacting the aqueous composition to the article to clean the article and reduce corrosion to the surface of the article.   
     
     
         17 . The method according to  claim 16 , wherein the cleaning agent constitutes from about 0.5 wt % to about 10 wt % of the warewashing composition. 
     
     
         18 . The method according to  claim 16 , wherein the corrosion inhibitor constitutes between about 0.5 wt % and about 10 wt % of the warewashing composition. 
     
     
         19 . The method according to  claim 16 , wherein the warewashing composition comprises less than about 1 wt % phosphorus-containing compounds. 
     
     
         20 . The method according to  claim 16 , wherein the alkaline source constitutes between about 10 wt % and about 30 wt % of the warewashing composition. 
     
     
         21 . The method according to  claim 16 , wherein the alkaline source comprises at least one of an alkali metal carbonate, an alkali metal hydroxide and a mixture thereof. 
     
     
         22 . The method according to  claim 16 , wherein the aqueous composition has a pH of about 8. 
     
     
         23 . The method according to  claim 16 , wherein the aqueous composition has a solids content of at least about 0.05 wt %. 
     
     
         24 . The method according to  claim 14 , further comprising depositing a film on a surface of the article. 
     
     
         25 - 37 . (canceled)