Both highly alkaline, based on the alkali metal hydroxides, and mildly alkaline, based on an alkali metal silicate, cast detergent compositions are known. A great deal of attention has focused on formation of solid cast alkaline cleaning compositions in view of the inherent safety, high performance, convenience, and ease of use of the cast materials. Broadly I have found that the high performance alkaline cleaners can be made by blending alkail metal hydroxides, hardness sequestering agents and other optional compositions with water of hydration at elevated temperatures, casting the compositions and permitting the compositions to cool and solidify. I have also found that mildly alkaline compositions can also be cast by combining alkali metal silicates, hardness sequestering agents, and an inorganic composition that can act as hydrating-solidifying agents at low temperatures in the presence of hydrating amounts of water.
Both highly alkaline and mildly alkaline cast detergent compositions can provide excellent cleaning properties. The highly alkaline cleaning compositions as a result of the use of sodium hydroxide and hardness sequestering agents are highly effective in removing even the most stubborn soils from institutional and industrial ware. Mildly alkaline compositions have also been successfully used in high volume institutional cleaning systems, and have the added benefit that the silicates protect metal and glass surfaces from corrosion caused by the alkaline pH of the cleaner.
However, in a continual effort to provide cast materials having a variety of useful properties and improved cleaning efficiency, I have sought to increase the level of available chlorine and to increase the cleaning capacity of the mildly alkaline compositions by establishing the optimum levels of active components which provide the highest cleaning activity.
USPTO Backgrounds
USPTO Backgrounds