Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-12-20
2002-12-17
Delcotto, 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...
C510S303000, C510S304000, C510S310000, C510S311000, C510S372000, C510S376000, C510S466000, C510S499000, C510S500000, C510S506000, C008S142000
Reexamination Certificate
active
06495502
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of bleaching compositions, in particular to a bleaching composition comprising bleach catalysts suitable for use at low temperatures, e.g. less than 25° C. In addition the present invention relates to a method of preparing a bleaching composition and method of bleaching, especially textile articles.
BACKGROUND OF THE INVENTION
Peroxygen bleaches are well known for their ability to remove stains from substrates. Traditionally, the substrate is subjected to hydrogen peroxide, or to substances which can generate hydrogen peroxide radicals, such as inorganic or organic peroxides. Generally, these compositions must be activated. One method of activation is to employ wash temperatures of 60° C. or higher. However, these high temperatures often lead to inefficient cleaning, and can also cause premature damage to the substrate.
A preferred approach is to activate these compositions by generating hydrogen peroxide in the presence of organic precursor compounds, also called bleach activators. These compositions are employed for many commercial laundry powders. For example, various European systems are based on tetra acetyl ethylenediamine (TAED) as the organic precursor coupled with sodium perborate or sodium percarbonate, whereas in the United States laundry bleach products are typically based on sodium nonanoyl oxy benzene sulphonate (SNOBS) as the organic precursor coupled with sodium perborate.
Precursor systems are generally effective but still exhibit several disadvantages. For example, organic precursors are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, precursor systems have large formulation space requirements so that a significant proportion of a laundry powder must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated powders. Moreover, precursor systems do not bleach very efficiently in countries where consumers have wash habits entailing low dosage, short wash times, low temperatures and low wash liquor to substrate ratios.
Alternatively, or additionally, hydrogen peroxide and peroxy systems can be activated by bleach catalysts, such as by complexes of iron and the ligand N4Py (i.e. N,N-bis(pyridin-2-yl-methyl)-bis(pyridin-2-yl)methylamine) disclosed in WO95/34628, or the ligand Tpen (i.e. N,N,N′, N′-tetra(pyridin-2-yl-methyl)ethylenediamine) disclosed in WO97/48787. EP-A-408 131, EP-A-384503, EP-A-458 398, U.S. Pat. No. 5,194,416, WO 96/06157 and WO 98/39405 disclose catalyst wherein the organic part has a macrocyclic structure. Obviously, being catalysts, these bleach catalysts remain active and are not utilised in the reaction like precursors. Therefore, bleach catalysts have the advantage that little formulation space is required as the catalysts are used in minute amounts.
EP-A-909 809 discloses the use of iron catalysts; EP-A-458 397, EP-A-458 398, the use of manganese catalysts; EP-A-408 131 and EP-A-272 030 the use of cobalt catalysts—all for bleaching in combination with a source of peroxide or peroxy acid. All these documents describe bleaching in conventional bleaching compositions comprising aqueous wash liquor.
However, relatively high temperatures are usually employed to get effective bleaching action with bleach catalysts. A drawback of the use of these high temperatures is that the dyes in garments will be damaged more at increasing temperatures (see e.g. M. E. Burns, G. S. Miracle, A. D. Wiley, Surf. Sci. Series, 1998, page 165-203). Another drawback is that certain fabric types, such as wool, are known to undergo dimensional changes at elevated temperatures. Thus, there is a continuing need for bleach compositions comprising bleach catalysts that are effective at low temperatures.
Surprisingly we have now found it is possible to obtain effective bleaching using bleach catalysts at low temperatures, provided that the bleaching occurs in a particular bleaching composition wherein compared to conventional bleaching compositions the water is replaced by liquid carbon dioxide.
U.S. Pat. No. 5,431,843 and WO-98/23532 describe the use of organic peracid precursors along with a source of hydrogen peroxide for use in condensed fluid medium at 20° C. for bleaching of stained garments. At temperatures as high as 80° C. iron metalloporphyrin catalyst has been shown to oxidise cyclohexene in supercritical carbon dioxide (E. R. Birnbaum, et al. J. Mol. Catal. A, 139, 11-24 (1999). However, no where in the art is it taught to bleach with bleach catalysts in liquid carbon dioxide at low temperatures.
SUMMARY OF THE INVENTION
Accordingly, the inventive bleaching composition for low temperature bleaching comprises of
a) from 0.05 microM to 50 mM of an organic substance which forms a complex with a transition metal, the complex catalysing bleaching of a substrate with active oxygen;
b) a source of active oxygen corresponding to 0.05 to 100 microM of active oxygen; and
c) an effective amount of liquid carbon dioxide, preferably held at 25° C. or less, more preferably at 20° C. or less, more preferably at 18° C. or less, most preferably at 16° C. or less.
In addition, the present invention encompasses a bleaching method comprising the steps of
a) loading articles in a pressurisable vessel; and
b) contacting the items with a composition according the invention.
Furthermore, the present invention encompasses a method of preparing a bleaching composition according to the invention comprising the step dissolving or dispersing the organic substance in a compatible solvent prior to mixing the organic substance with the carbon dioxide.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a bleaching composition which provides effective bleaching at very low temperatures. The bleaching composition is defined as the composition wherein the actual bleaching occurs analogous to a wash liquor. In practice this bleaching composition may be prepared by adding a bleaching product to the carbon dioxide analogous to adding a detergent product to the wash liquor.
The bleaching composition may be used to bleach and/or clean any suitable article. The items to be cleaned should be compatible with the liquid carbon dioxide. Preferably, the items include garments and domestic articles with hard surfaces. The bleaching composition is especially useful to clean garments with bleachable stains.
For purposes of the invention, the following definitions are used:
“The bleaching composition” describes the total of the liquid carbon dioxide, the bleach catalyst, the source of active oxygen, the modifier if present and optionally other additives.
“Additives” are compounds to enhance the bleaching and/or cleaning effect of the bleaching composition such as surfactants, whiteners, softners, enzymes, perfume and antistat.
“Liquid carbon dioxide” means carbon dioxide which is placed at temperatures of about 30° C. or less.
“Supercritical fluid carbon dioxide” means carbon dioxide which is at or above the critical temperature of 31° C. and a critical pressure of 7.2 Mpa (71 atmospheres) and which cannot be condensed into a liquid phase despite the addition of further pressure.
The term “densified carbon dioxide” encompasses both liquid and supercritical fluid carbon dioxide.
It is noted that other densified molecules having supercritical properties may also be employed alone or in mixture. These molecules include methane, ethane, propane, ammonia, butane, n-pentane, n-hexane, cyclohexane, n-heptane, ethylene, propylene, methanol, ethanol, isopropanol, benzene, toluene, p-xylene, sulfur dioxide, chlorotrifluoromethane, xenon trichlorofluoromethane, perfluoropropane, chlorodifluoromethane, sulfur hexafluoride and nitrous oxide.
GENERIC GROUP DEFINITION
Throughout the description and claims generic groups have been used, for example alkyl, alkoxy, aryl. Unless otherwise specified the following are preferred group restrictions that may be applied to generic groups found with
Bijl Dirk Johannes
Hage Ronald
Kevelam Jan
Koek Jean Hypolites
Murphy Dennis Stephen
Delcotto Gregory
Honig Milton L.
Unilever Home & Personal Care USA , division of Conopco, Inc.
LandOfFree
Bleaching composition for dry cleaning containing transition... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bleaching composition for dry cleaning containing transition..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bleaching composition for dry cleaning containing transition... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2968183