Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
2000-02-07
2002-06-18
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S109000, C510S238000, C510S277000, C510S365000, C510S424000, C424S070190, C424S074000
Reexamination Certificate
active
06407051
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to microemulsion detergent compositions and methods for removing hydrophobic soil from a variety of articles. In particular, the invention relates to a microemulsion detergent composition including water, oil, and a blend of nonionic surfactants. Articles that can be cleaned using the microemulsion detergent compositions of the invention include hard surfaces, textiles, skin, and hair. The invention additionally relates to controlling the stability of a microemulsion detergent composition over a broad temperature range.
BACKGROUND OF THE INVENTION
Microemulsions are disclosed for soil removal. For example, U.S. Pat. No. 4,909,962 to Clark describes a substantially clear microemulsion material that can be used in a variety of cleaning applications. The material can be diluted with water to form a use solution.
While microemulsion cleaning technology has proved useful as a vehicle for delivering typically anionic, nonionic or anionic amine oxide surfactant blends to a cleaning location, the typical microemulsion compositions do not provide desired soil removal when challenged with a strongly hydrophobic soil and in particular, a strongly hydrophobic soil containing a substantial quantity of hydrophobic particulate material. Particularly difficult hydrophobic soils include hydrophobic petroleum based lubricant or oil and used motor oil containing carbonaceous particulates.
Examples of microemulsion detergent technology are found in U.S. Pat. No. 5,597,792 to Klier et al.; U.S. Pat. No. 5,415,813 to Misselyn et al.; U.S. Pat. No. 5,523,014 to Dolan et al.; and U.S. Pat. No. 5,616,548 to Thomas et al. In general, microemulsions including anionic or cationic surfactants are described by these patents.
Many prior art microemulsions are stable at a fairly narrow temperature range. Under low temperature and high temperature conditions often encountered when shipping product or storing product in a warehouse, microemulsions exhibiting stability in a fairly narrow temperature range tend to become unstable. As a result, the microemulsion breaks and the effectiveness of the composition for removing soil is decreased. In addition, when a microemulsion breaks, it may take a considerable amount of time for the microemulsion to reform. In general, cleaning operations until a composition forms a microemulsion in order to obtain optimum cleaning benefits.
SUMMARY OF THE INVENTION
A microemulsion detergent composition is provided by the invention. The microemulsion detergent composition includes an effective microemulsion forming amount of water, an effective microemulsion forming amount of a nonionic surfactant mixture, and an effective microemulsion forming amount of oil. The microemulsion detergent composition can be characterized as exhibiting at least a 90% transmission of visible light through a 1 cm cell. In addition, the microemulsion detergent composition is preferably one which will maintain a microemulsion as a concentrate containing 30 wt. % water, and will maintain a microemulsion as a use solution at 99 wt. % water. In addition, the microemulsion detergent composition preferably maintains a microemulsion stability range of at least about 10° C.
The nonionic surfactant mixture preferably includes an alcohol ethoxylate surfactant and an alkyl polyglucoside surfactant. The alcohol ethoxylate surfactant is preferably a C
6-24
alcohol ethoxylate surfactant having between about 1 and about 20 moles ethylene oxide repeating units. The alkyl polyglucoside surfactant is preferably a C
6-24
alkyl polyglucoside surfactant having a degree of polymerization of between about 1 and about 10. In addition, the ratio of alcohol ethoxylate surfactant to alkyl polyglucoside surfactant is preferably provided between about 1:4 and about 4:1. Preferably, the weight ratio of alcohol ethoxylate surfactant to alkyl polyglucoside surfactant is between about 1:3 and about 3:1. The oil component of the microemulsion is preferably an oil which exhibits a water solubility at 22° C. of less than one percent by weight.
When the microemulsion detergent composition is provided as a concentrate, it preferably contains between about 30 wt. % and about 60 wt. % water, between about 1 wt. % and about 30 wt. % oil, and between about 20 wt. % and about 60 wt. % nonionic surfactant mixture. When the microemulsion detergent composition is provided as a use solution, the concentration of water can be adjusted depending upon the particular application for which the microemulsion is used. For example, when the microemulsion detergent composition is used as a hand soap, the use solution can contain between about 30 wt. % and about 99 wt. % water. When the microemulsion detergent composition is used as a pre-spotter, the use solution preferably includes between about 30 wt. % and about 60 wt. % water. When the microemulsion detergent composition is used as a parts washer or as an automobile cleaner, the use solution is preferably provided containing between about 90 wt. % and about 99.9 wt. % water.
The microemulsion detergent composition is preferably free of a surface active amount of surfactants containing at least one of the following groups: protonated amines, quaternary ammonium compounds, sulfanates, sulfates, ether sulfates, carboxylates, and phosphates. In addition, the microemulsion detergent composition can be provided so that it is substantially free of volatile organic compounds (VOC). In general, volatile organic compounds can include C
13
and lower compounds which can include certain hydrocarbons. Preferably, the microemulsion detergent composition provides a VOC level of less than about 300 ppm, more preferably less than about 100 ppm, and even more preferably less than about 10 ppm according to ASTM D 3960-87.
The microemulsion detergent composition can include a splitting agent for controlling the splitting properties of the microemulsion. The splitting agent may be useful for splitting the microemulsion in order to separate the soil from the surfactants. It may be desirable to periodically split a microemulsion use solution to remove soil and then allow the microemulsion to reform to provide a detersive use solution. For example, the splitting properties of the microemulsion can be controlled by altering the temperature of the microemulsion. A preferred splitting agent includes an amphoteric surfactant. The concentrate can include between about 1 wt. % and about 20 wt. % amphoteric surfactant to provide desired splitting properties.
The pH of the microemulsion detergent composition should be maintained at less than about 8 when an amphoteric surfactant is incorporated into the detergent composition. Preferably, the pH is selected to stay below the pK
a
of the amphoteric surfactant.
A method of removing hydrophobic soil from an article is provided by the invention. The method includes the step of contacting an article containing a hydrophobic soil with a microemulsion detergent composition. Exemplary articles which can be contacted with a microemulsion detergent composition include fabric, art surfaces, hands, and automobile exterior. The microemulsion detergent composition can preferably be used as a car wash composition. Accordingly, the microemulsion detergent composition can be provided as a use solution and sprayed on the exterior of a motor vehicle such as a car or truck. In addition, the microemulsion detergent composition can be used as a skin and/or hair cleaner.
DETAILED DISCUSSION OF THE INVENTION
The invention relates to microemulsion detergent compositions containing a mixture of nonionic surfactants, water, and oil. The microemulsion detergent composition can be referred to herein more simply as the microemulsion. The microemulsion can include a splitting agent for controlling the splitting properties of the microemulsion at a particular temperature. The microemulsion detergent composition can include additional components including antimicrobial agents, corrosion inhibitors, lubricants, brightening agents, antiredeposition agents, inorganic salts,
Falbaum David
Hei Robert D.P.
Man Victor F.
Mattia Paul
Smith Kim
Ecolab Inc.
Gupta Yogendra N.
Webb Gregory E.
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