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
2002-11-12
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
06479447
ABSTRACT:
FILED OF THE INVENTION
The present invention relates to the field of bleaching compositions, in particular to a bleaching composition suitable for bleaching low temperatures, say less than 25° C. In addition the present invention relates to a method of preparing a bleaching composition and method of bleaching articles, especially textile articles.
BACKGROUND OF THE INVENTION
Bleaching compositions to clean textile articles are well known in the art. A well known problem is that bleaching is often only optimal at high temperatures causing damage to dye and fabric. Carbon dioxide has also been used to clean laundry and U.S. Pat. No. 5,431,843, U.S. Pat. No. 5,486,212 and WO-98/23532 describe the use of organic peracid precursors along with a source of hydrogen peroxide for use in carbon dioxide at 20° C. for bleaching of stained garments.
However, peracid precursors 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 cleaning composition must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated compositions. Moreover, precursor systems do not bleach very efficiently, i.e., relatively long wash times, high temperatures and high concentrations of bleach agents are needed. For example, U.S. Pat. No. 5,431,843 and U.S. Pat. No. 5,486,212 describe wash time of one hour to bleach textile using peracid precursors.
In aqueous wash liquors it is known to activate hydrogen peroxide and peroxy systems by bleach catalysts, such as 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.
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 which do not show one or more of these drawbacks.
Surprisingly, the present invention provides a bleaching composition that shows excellent bleaching at short wash times and low temperatures provided that a special selection of bleach catalyst is used and that the bleaching medium is mainly carbon dioxide. The use of bleach catalyst to effectively clean textile articles at low temperatures in carbon dioxide is not disclosed in the prior art to the best of our knowledge.
SUMMARY OF THE INVENTION
Accordingly, the inventive bleaching composition suitable for use at low temperatures comprises of
a) from 0.05 microM to 50 mM of an organic substance which forms a complex with a transition metal having a logP of less than 3;
b) a source of active oxygen corresponding to 0.05 to 100 MM 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.
Obviously, being catalysts, these bleach catalysts remain active and are not utilised in the reaction like precursors. Therefore, the present invention has the advantage that little formulation space is required as the catalysts are used in minute amounts.
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.
Very good bleaching was obtained with a special selection of bleach catalysts. Unexpectedly, these bleach catalysts are relatively incompatible with the hydrophobic carbon dioxide, i.e., the catalysts are relatively hydrophilic catalysts. Accordingly, another aspect of the invention provides a method of preparing said bleaching composition.
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 within compounds disclosed herein:
alkyl: linear and branched C1-C8-alkyl,
alkenyl: C2-C6-alkenyl,
cycloalkyl: C3-C8-cycloalkyl,
alkoxy: C1-C6-alkoxy,
alkylene: selected from the group consisting of: methylene; 1,1-ethylene; 1,2-ethylene; 1,1-propylidene; 1,2-propylene; 1,3-propylene; 2,2-propylidene; butan-2-ol-1,4-diyl; propan-2-ol-1,3-diyl; 1,4-butylene; cyclohexane-1,1-diyl; cyclohexan-1,2-diyl; cyclohexan-1,3-diyl; cyclohexan-1,4-diyl; cyclopentane-1,1-diyl; cyclopentan-1,2-diyl; and cyclopentan-1,3-diyl,
aryl: selected from homoaromatic compounds having a molecular weight under 300,
arylene: selected fr
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.
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