Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2002-01-31
2002-11-05
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S470000, C008S142000, C008S158000, C008S159000, C008S149100, C008S149200
Reexamination Certificate
active
06475968
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to a surfactant comprising a carbohydrate group. More particularly, the invention is directed to a surfactant comprising a carbohydrate group that results in superior cleaning properties in a dry cleaning system.
BACKGROUND OF THE INVENTION
In many cleaning applications, it is desirable to remove contaminants (e.g., stains) from substrates, like metal, ceramic, polymeric, composite, glass and textile comprising substrates. Particularly, it is highly desirable to remove contaminants from clothing whereby such contaminants include dirt, salts, food stains, oils, greases and the like.
Typically, dry-cleaning systems use organic solvents, like chlorofluorocarbons, perchloroethylene and branched hydrocarbons to remove contaminants from substrates. In response to environmental concerns, other dry-cleaning systems have been developed that use inorganic solvents, such as densified carbon dioxide, to remove contaminants from substrates. The systems that use carbon dioxide to remove contaminants from substrates generally employ a surfactant and a polar co-solvent so that a reverse micelle may be formed to trap the contaminant targeted for removal.
In view of the environmental concerns associated with dry cleaning in, for example, halogenated hydrocarbons, many cleaning establishments have expressed their interests in cleaning with continuous phase solvents that comprise densified gases such as densified carbon dioxide as well as a biodegradable functionalized hydrocarbon or a silicon comprising solvent. Unfortunately, however, cleaning with such solvents is not made easy because only very few surfactants are compatible with such continuous phases.
It is of increasing interest to develop surfactants that enhance cleaning in a system that uses a densified gas, functionalized biodegradable hydrocarbon and/or a silicon comprising solvent. This invention, therefore, is directed to a surfactant comprising a carbohydrate group that unexpectedly results in superior cleaning properties in a dry cleaning system that utilizes a densified gas, a functionalized biodegradable hydrocarbon and/or silicon comprising solvent.
Additional Information
Efforts have been disclosed for dry cleaning with carbon dioxide. In U.S. Pat. No. 5,676,705, a superior dry cleaning method which employs densified carbon dioxide is described.
Other efforts have been disclosed for dry cleaning with carbon dioxide. In U.S. Pat. No. 5,683,473, a superior method for dry: cleaning fabrics with a surfactant having a polysiloxane, branched polyalkylene oxide or halocarbon group is described.
Still further, U.S. Pat. No. 5,683,977 discloses a superior dry cleaning system with carbon dioxide and a surfactant adjunct.
Finally, in U.S. Pat. No. 5,866,005, a cleaning process using carbon dioxide as a solvent along with molecularly engineered surfactants is described.
None of the references above describe the use of surfactant comprising a carbohydrate group and a hydrocarbon group wherein the hydrocarbon group is more soluble in the dry cleaning solvent than the carbohydrate group.
SUMMARY OF THE INVENTION
In a first embodiment, the present invention is directed to a dry cleaning system comprising a surfactant comprising a hydrocarbon group which is solvent-philic and a carbohydrate group which is less solvent-philic than the hydrocarbon group.
In a second embodiment, the present invention is directed to a dry cleaning system comprising a dry cleaning solvent, and a surfactant or mixture of surfactants having the formula:
AXB I
wherein
(i) A is a moiety which is more soluble in the dry cleaning solvent than B;
(ii) X is
a divalent group comprising P or
(iii) B is a carbohydrate group,
(iv) Z is H, or a C
1-10
alkyl group, or
and G is a C
1-6
alkyl
(v) m is an integer from 0 to about 10, and d is 0 when m is 0 and 1 when m is ≧1,
with the proviso that A is not a siloxane, a halocarbon or a polyalkylene oxide.
In a third embodiment, the present invention is directed to a method for dry cleaning using the dry cleaning system of the first or second embodiment of the present invention.
Carbohydrate group, as used herein, is defined to mean a carbohydrate having at least one bond to an ester, ether, amine group, amide group, or divalent group comprising P. A divalent group comprising P is meant to mean a group derived from phosphine or phosphate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There generally is no limitation with respect to the surfactant used in this invention as long as the surfactant will enhance cleaning in a system which utilizes a continuous phase solvent comprising a densified gas, biodegradable functionalized hydrocarbon, a silicon comprising solvent, or a mixture thereof.
Often, however, the surfactants which may be used in this invention have A as a C
3
to C
15
alkyl group (preferably a C
8
to C
10
alkyl group), or an aryl group; B as a monosaccharide or disaccharide, and preferably, not a polysaccharide. In the structure, X is an ester, ether, or amine group, and preferably, an ester group.
Regarding the carbohydrate group, the only limitation with respect to the carbohydrate group is that the carbohydrate group is less soluble in the dry cleaning solvent than A. Such a carbohydrate group may be selected from the group consisting of glucose, fructose, sucrose, galactose, lactose, ribose, lyxose, allose, altrose, erythrose, talose and mannose, including derivatives and disaccharides prepared therefrom.
When preparing the surfactant described in the present invention, conventional reactions, like those involving carboxylic acids and alcohol groups (esterifications); alkyl halides and alkoxides (Williamson ether synthesis); and reduction reactions involving ketones and primary amines (amine synthesis), may be used to produce the desired surfactant.
It is also noted herein that the surfactants which may be used in this invention are not limited with respect to where the moiety represented by A is bonded, via the group represented by X, to the carbohydrate group. Therefore, the moiety represented by A may be bonded (via the group represented by X) to a carbon within the carbohydrate ring or a group pendant to the carbons which make up the carbohydrate ring Moreover, the surfactant employable in the present invention can include those which display carbohydrate ring opening after the moiety represented by A is attached to the carbohydrate ring by the group represented by X. Such a surfactant may also include a dimeric or trimeric surfactant generated from AXB monomers. A preferred dimeric surfactant is 1,4-bis-[6-O-(n-octyl-2,3,4-tri-O-benzyl-alpha-D-glucopyranosid)]succinate. It is also noted herein that microorganisms may be the source of the surfactants represented by AXB. Thus, surfactants which are classified as biosurfactants or microbial surfactants may be used in the dry cleaning system of the present invention.
A more detailed description of the types of surfactants comprising a carbohydrate group which may be used in this invention may be found in
Colloids and Surfaces A: Physicochemical and Engineering Aspects,
102 (1995) 91-97, entitled “Non-ionic Sugar-Based Surfactants: Self Assembly and Air/Water Interfacial Activity” by Soderberg et al.;
Langmuir
1997, 13, 6857-6860, entitled “Nonionic Boloamphiphiles and Gemini Surfactants Based on Carbohydrates” by Pestman et al.;
Langmuir
1999, 15, 2009-2014, entitled “Thermodynamics of Micellization of Nonionic Saccharide-Based N-Acyl-N-Alkylaldosylamine and N-Acyl-N-Alkylamino-1-deoxyalditol Surfactants” by Pestman et al.;
Langmuir
2001, 17, 1941-1949, entitled “Studies of N-Docecyllacto-bionamide, Maltose 6′-O-Dodecanoate, and Octyl-P-glucoside with Surface Tension, Surface Force, and Wetting Techniques” by Kjellin et al.;
Biosurfactants and Biotechnology
, pages 21-41, (1987) by Marcel Dekker, Inc., and
Tetrahedron
55 (1999) 12711-12722, entitled “New Dimeric Surfactants from Alkyl Glucosides” by Castro et al., the disclosures of which are all incorporated
Binder David Alan
Murphy Dennis Stephen
Boyer Charles
Koatz Ronald A.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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