Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
1999-01-25
2001-10-23
El-Arini, Zeinab (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S002000, C134S003000, C134S025200, C510S108000, C510S161000, C510S219000, C510S238000, C510S243000, C510S372000, C510S375000, C510S379000, C510S380000
Reexamination Certificate
active
06306219
ABSTRACT:
TECHNICAL FIELD
The present invention is in the field of bleaching compositions, preferably liquid or gel detergents. More specifically, the invention relates to a method for removing stains, odors and for disinfecting plastics and other hard surface substrates by applying a bleaching composition, preferably a liquid or gel detergent composition, and subjecting the substrate to microwaves. This method provides enhanced cleaning and improved stain removal on plastics, and other substrates. These cleaning compositions comprise a bleaching agent, preferably diacyl peroxide in a liquid or gel detergent formulation.
BACKGROUND OF THE INVENTION
Detergents used for washing tableware (i.e., glassware, china, silverware, plastic, etc.) or kitchenware in the home or institution have long been known. Dishwashing in the seventies is reviewed by Mizuno in Vol. 5, Part III of the Surfactant Science Series, Ed. W. G. Cutler and R. C. Davis, Marcel Dekker, N.Y., 1973, incorporated by reference. The particular requirements of cleansing tableware and leaving it in a sanitary, essentially stainless, residue-free state has indeed resulted in so many particular compositions that the body of art pertaining thereto is now recognized as quite distinct from other cleansing product art. Additionally, the body of art pertaining to fabric cleaning is immense and encompasses many formulations designed for stain removal, many including bleaches.
However, consumers continue to experience problems with stain removal on various substrates, including typical kitchenware surfaces. In particular, formulators have experienced difficulties in formulating detergents which remove both hydrophobic and hydrophilic stains. Typically for stain removal, formulators have turned to chlorine bleach or sources of hydrogen peroxide and bleach activators.
Numerous substances have been disclosed in the art as effective bleach activators. One widely-used bleach activator is tetraacetyl ethylene diamine (TAED). TAED provides effective hydrophilic cleaning especially on beverage stains, but has limited performance on hydrophobic stains, dingy stains and body soils. Another type of activator, such as nonanoyloxybenzenesulfonate (NOBS) and other activators which generally comprise long chain alkyl moieties, is hydrophobic in nature and provides excellent performance on dingy stains and carotenoid stains.
It would seem that a combination of bleach activators, such as TAED and NOBS, would provide an effective detergent composition which would perform well on both hydrophilic and hydrophobic soils and stains. However, many of the hydrophilic activators developed thus far, including TAED, have been found to have limited efficacy, especially at laundry liquor temperatures below 60° C. Another consideration in the development of consumer products effective on both types of soils is the additional costs associated with the inclusion of two or more bleach activators. Accordingly, it is of substantial interest to the manufacturers of bleaching systems to find a less expensive type of bleaching activator.
Chlorine bleaches are effective for stain andlor soil removal. While chlorine bleach is a very effective cleaning agent, it is not compatible with a variety of detergent ingredients and may require lengthy soaking time in which the bleach and the stained substrate must remain in contact to ensure stain removal.
Another known bleaching source is diacyl peroxides (DAPs). Although DAPs have been disclosed for use in the laundry and anti-acne area, they have had limited success in liquid or automatic dishwashing detergent area. In the laundry field certain diacyl peroxides have been disclosed as beneficial in cleaning tea stains from fibrous material. It has now been discovered that DAPs can improve stain removal performance on plastics.
Another problem facing formulators is stability of the bleaching agents and other individual ingredients over time, especially in liquid products. This is particularly true for diacyl peroxides in alkaline conditions.
As a consequence to the above-identified problems, there has been a substantial amount of research to develop bleaching systems which are stable and effective in liquid formulations and in which the amount of soaking time needed to remove stains is greatly reduced. By the present invention, it has now been discovered that certain bleaching agents are stable and perform very well on stains when the bleaching agent is applied to a substrate and subjected to microwaves. Accordingly, the present invention solves the long-standing need for an inexpensive bleaching system which performs efficiently and effectively under mixed soil load conditions, especially mixtures of hydrophobic and hydrophilic soils.
The detergent compositions provided herein have the property of removing stains, especially tea, fruit juice and carotenoid stains objected to by the consumer from plastic dishware, glass, wood, and many other known substrates when exposed to microwaving from any typical household or commercial microwave. The compositions have other cleaning benefits in addition to stain removal advantages such as deodorizing and disinfecting. Thus, provided herein is a method of removing stains from a substrate by applying a bleaching compositions and exposing the stained substrate to microwaves to provide powerful cleaning of wide-ranging stains while retaining the advantages of a stable, mild product matrix.
SUMMARY OF THE INVENTION
The invention herein is a method for treating substrates comprising the steps of:
a) contacting a substrate, in the presence of water or a solvent which generates heat under microwave radiation, with a treating composition comprising an effective bleaching agent;
b) subjecting the substrate to microwaves for a sufficient period to effectively treat the substrate.
There are also provided embodiments wherein additional components, especially surfactant, solvent, clay, polycarboxylate thickeners, baking soda, carbonates, phosphates, hydrobenzoic acid, dicarboxylic acid, siloxanes, perfumes, bleach catalysts, water, and mixtures thereof. Said compositions can have a pH of from about 3 to about 13.
Without intent to limit the types of substrates that may be treated, examples of hard surface substrates which can be treated by this method include ceramic, plastic, surgical/medical equipment, baby bottles, dishware, dentifrice/dentures, wood, glass, and mixtures thereof. Examples of bleaching agents which are highly preferred for use herein included: diacyl peroxide, a source of hydrogen peroxide with or without a bleach activator, chlorine bleach and mixtures thereof.
Although this method can be employed to assist in bleaching the substrate for any desired purpose, examples of likely uses include one or more of the following: stain removal, stain reducing, deodorizing, or disinfecting. The substrate after being treated with the bleach composition is then subjected to microwaves for a sufficient time to “treat” the substrate to the desired end result, i.e. stain reduction, deodorizing, disinfecting. Typically a “sufficient time” in step b) is from about 1 second to about 2 minutes, preferably from about 10 seconds to about 45 seconds.
The method herein when employed to remove or reduce stains is highly effective on hydrophobic stains such as tomato stains and dingy stains. However, the method can also be employed with very good results on hydrophilic stains such as teas stains on ceramic or other substrates. Other example wherein the method is highly effective include the reduction or removal of hydrophobic stains on hydrophobic substrates and the reduction or removal of hydrophilic stains on hydrophilic substrates. An example of hydrophobic stains on hydrophobic substrates include tomato sauce on plastic. An example of hydrophilic stains on hydrophilic substrates include tea stains on ceramic. Included below are examples of treating composition which can be employed in the method of this invention.
1) A sprayable liquid or sprayable gel detergent compositions especially effective at cleaning sta
Hutton Howard David
Ofosu-Asante Kofi
El-Arini Zeinab
Miller Steven W.
Reed T. David
The Procter & Gamble & Company
William Zerby Kim
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