Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-07-16
2004-05-25
Webb, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S220000, C510S224000, C510S504000, C510S506000, C510S514000, C134S026000
Reexamination Certificate
active
06740628
ABSTRACT:
TECHNICAL FIELD
The present invention is in the field of dishwashing, in particular it relates to dishwashing methods suitable for the removal of cooked-, baked- and burnt-on soils from cookware and tableware.
BACKGROUND OF THE INVENTION
Cooked-, baked- and burnt-on soils are amongst the most severe types of soils to remove from surfaces. Traditionally, the removal of cooked-, baked- and burnt-on soils from cookware and tableware requires soaking the soiled object prior to a mechanical action. Apparently, the automatic dishwashing process alone does not provide a satisfactory removal of cooked-, baked- and burnt-on soils. Manual dishwashing process requires a tremendous rubbing effort to remove cooked-, baked- and burnt-on soils and this can be detrimental to the safety and condition of the cookware/tableware.
The use of cleaning compositions containing solvent for helping in the removal of cooked-, baked- and burnt-on solids is known in the art. For example, U.S. Pat. No. 5,102,573 provides a method for treating hard surfaces soiled with cooked-on, baked-on or dried-on food residues comprising applying a pre-spotting composition to the soiled article. The composition applied comprises surfactant, builder, amine and solvent. U.S. Pat. No. 5,929,007 provides an aqueous hard surface cleaning composition for removing hardened dried or baked-on grease soil deposits. The composition comprises nonionic surfactant, chelating agent, caustic, a glycol ether solvent system, organic amine and anti-redeposition agents. WO-A-94/28108 discloses an aqueous cleaner concentrate composition, that can be diluted to form a more viscous use solution comprising an effective thickening amount of a rod micelle thickener composition, lower alkyl glycol ether solvent and hardness sequestering agent. The application also describes a method of cleaning a food preparation unit having at least one substantially vertical surface having a baked food soil coating. In practice, however, none of the art has been found to be very effective in removing baked-on, polymerized soil from metal and other substrates.
The use of solvents in the automatic dishwashing context is also known. JP-A-10,017,900 discloses an automatic dishwashing auxiliary composition comprising non-ionic low foaming surfactant, organic solvent and water. The composition delivers detergency and drying benefits. JP-A-11,117,000 discloses a cleaning assistant composition for automatic dishwashing machines comprising surfactant, organic high-molecular polyelectrolyte, water-soluble solvent and water. The claimed assistant composition helps in the cleaning of stubborn dirt such as that due to oil or lipstick.
There is still the need for a method and products having improved efficacy for the removal of cooked-, baked- and burnt-on soils from cookware and tableware using an automatic dishwashing machine and avoiding the use of a pre-treatment step.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a method of removing cooked-, baked-, or burnt-on food soil (such as grease, meat, dairy, fruit, pasta and any other food especially difficult to remove after the cooking process) from cookware and tableware (including stainless steel, glass, plastic, wood and ceramic objects). The method comprises washing the cookware/tableware in an automatic dishwashing machine in the presence of an organic solvent system (comprising a single solvent compound or a mixture of solvent compounds) having a volatile organic content above 1 mm Hg of less than about 50%, preferably less than about 20% and more preferably less than about 10% by weight of the solvent system. Herein volatile organic content of the solvent system is defined as the content of organic components in the solvent system having a vapor pressure higher than the prescribed limit at 25° C. and atmospheric pressure.
The optimum concentration of the solvent in the wash liquor is from about 100 ppm to about 10000 ppm, preferably from about 200 to about 8000 and more preferably from about 500 to about 5000 ppm.
The washing process herein is preferably undertaken at low wash liquor surface tension, this being valuable, in conjunction with the defined solvent levels from the viewpoint of providing optimum cleaning performance of cooked-, baked- and burnt-on soils. Preferably, the surface tension of the wash liquor is less than about 35 mN/m, preferably less than about 32 mN/m more preferably less than about 30 mN/m and especially less than about 28 mN/m.
Thus, according to another aspect of the invention there is provided a method of removing cooked-, baked-, or burnt-on food soil from cookware and tableware comprising washing the cookware/tableware in an automatic dishwashing machine in the presence of an organic solvent system having a wash liquor concentration of from about 100 ppm to about 10000 ppm, preferably from about 200 to about 8000 and more preferably from about 500 to about 5000 ppm, and at a wash liquor surface tension of less than about 35 mN/m, preferably less than about 32 mN/m more preferably less than about 30 mN/m and especially less than about 28 mN/m.
The organic solvent system is preferably used in combination with a surfactant, especially a low foaming non-ionic surfactant and a detergency builder. Thus another embodiment of the invention provides a method of removing cooked-, baked-, or burnt-on food soil from cookware and tableware comprising washing the cookware/tableware in an automatic dishwashing machine in the presence of surfactant, detergency builder and an organic solvent system wherein the surfactant has a wash liquor concentration of from about 10 to about 1000, preferably from about 100 to about 600 ppm, the detergency builder has a wash liquor concentration of about 100 to about 5000, preferably from about 1000 to about 3000 ppm and the organic solvent system has a wash liquor concentration of from about 100 to about 10000 ppm, preferably from about 200 to about 8000 ppm and more preferably from about 500 to about 5000 ppm. The pH of the wash liquor will generally be in the alkaline range, preferably at least 10.5 or more preferably at least 11.0, this pH being provided by means of an alkalinity source or sources in one or more compositions used for delivery of the solvent, surfactant and builder.
The methods of the invention can be performed using a purpose-designed organic solvent composition, but in a preferred aspect, the invention envisages the use of a plurality of compositions including at least one organic solvent composition. The compositions can be delivered into the same or different cycles of the automatic dishwashing machine. The soiled cookware/tableware is washed in the resulting solvent-containing wash liquor.
Thus, according to another aspect of the invention, the removal of cooked-, baked-, or burnt-on food soil from cookware and tableware can be carried out by the use of one or more organic solvent compositions (wherein “solvent composition” is understood to comprise the organic solvent system and optional additional active ingredients and diluents) and one or more automatic dishwashing detergent compositions. The organic solvent composition can be built, unbuilt or generally unbuilt, but when used as an additive composition in conjunction with a dishwashing detergent composition, the solvent composition will normally be relatively unbuilt by comparison with the detergent composition. By “relatively unbuilt” is meant that under normal use conditions, the solvent composition will deliver a minor proportion (less than 50%, preferably less than 25%, more preferably less than 10% by weight) of the total builder delivered to the wash liquor by the one or more solvent compositions and the one or more detergent compositions. By “generally unbuilt” is meant that the composition contains less than about 5% by weight of detergency builder.
According to different embodiments of the present invention, the solvent compositions and automatic dishwashing detergent compositions can be delivered either at the same or at differ
Alam Elizabeth Ann
Bennie Brenda Frances
Campbell Mairi
DeNome Frank William
Ghosh Chanchal
The Procter & Gamble & Company
Waugh Kevin L.
Webb Gregory
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