Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2000-07-06
2003-06-24
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S180000, C510S238000, C510S239000, C510S240000, C134S038000, C134S039000, C134S040000
Reexamination Certificate
active
06583104
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to aqueous cleaning compositions which contain an organic solvent and are particularly useful in cleaning hard surfaces such as glass, ceramic tile and the like.
BACKGROUND OF THE INVENTION
Water-based hard surface cleaning compositions are well known, many having been disclosed in the literatures and a number have been sold commercially. Typically, such compositions contain a surfactant, an organic solvent or solvent system and water as well as a variety of other ingredients such as coupling agents, builders, alcohols, ammonia, pH modifiers, germicides, perfumes, opacifiers, dyes, etc. which may be chosen by the skilled formulator to satisfy the'requirements of a particular application.
It is well known that an organic solvent having excellent solvency for soils such as grease and wax needs to be present in water-based cleaning compositions to achieve acceptable results in cleaning hard surfaces such as glass, ceramic tile, etc. An appropriate organic solvent having good cleaning efficiency enhances an aqueous cleaning composition's ability to remove soils and dirt which may contain organic matter from the hard surface to be cleaned without leaving streaks or residues. However, because of recentregulatory efforts to reduce the presence of volatile organic compounds in products such as cleaning compositions which have significant exposure to the environment, the industry continues to look for more efficient solvent systems which can be used in smaller amounts while maintaining cleaning efficiency. In addition, for commercial acceptance, it is important that the organic solvent does not impart a strong or unpleasant odor to the cleaning composition.
Various glycol ethers, used alone or in combination with other organic solvents, have been recognized as a useful solvent component for aqueous cleaning compositions. For example, ethylene glycol butyl ether has been used as the solvent of choice in numerous commercial cleaning compositions for many years and is disclosed in prior art patents ( see, for example, U.S. Pat. No. 4,983,317). This glycol ether has acceptable cleaning efficiency and good solubility in water-based cleaning compositions. However, its cleaning, efficiency levels off at about 1% by weight in aqueous cleaning composition and, as the data in Table 1 shows, actually declines as more of the solvent is added thus limiting the cleaning efficiency which can be achieved by using this solvent alone.
European Patent Publication 0527625A2 discloses the use of up to about 1.5% ethylene glycol hexyl ether as a solvent in water-based cleaning compositions. This glycol ether has better cleaning efficiency than ethylene glycol butyl ether but is only soluble up to about 1% by weight in the water-based cleaning compositions thus requiring the use of coupling agents and/or cosolvents which may result in the presence of an undesirable level of volatile organics.
U.S. Pat. No. 3,882,038 discloses hard surface cleaning compositions containing certain classes of glycol ether compositions including those represented by the formula:
RO(C
2
H
4
O)
&mgr;
H
wherein R is an alkyl group containing from 5 to 8 carbon atoms, and &mgr; has a value of from 1 to 6, preferably 1 to 3, with the proviso that &mgr; has a value of from 1 to 4 when R contains five carbon atoms, and &mgr; has a value of 3 to 6 when R contains from 6 to 8 carbon atoms. This patent discloses a large number of glycol ethers which could be used as a solvent in water-based cleaning compositions including ethylene glycol amyl ether. This amyl ether product is shown by the patentee to have acceptable cleaning efficiency particularly when used with a coupling agent in water-based compositions containing a builder. The ethylene glycol amyl ether disclosed in U.S. Pat. No. 3,882,038 is typically prepared by the reaction of ethylene oxide and amyl alcohol. The “amyl” designation is understood by those knowledgeable in the art to be a mixture of isomers including 40 to 50% or more of the 2-methyl butyl isomer and up to 10% of the 3-methyl butyl isomer in addition to the n-pentyl species. The ethylene glycol amyl ether solvent, while offering an improvement in cleaning efficiency over ethylene glycol butyl ether solvent, has a strong odor and the presence of the 3-methyl butyl isomer creates potential toxicity problems making it unsuitable for commercial use. Thus amyl ether products such as that disclosed in U.S. Pat. No. 3,882,038 have never achieved acceptance in the marketplace for use as a solvent in water-based cleaning compositions.
SUMMARY OF THE INVENTION
According to the present invention, applicants have discovered that a specific ethylene glycol pentyl ether product is useful as a solvent component to provide improved water-based cleaning compositions. More specifically, the present invention relates to water-based cleaning compositions which comprise a surfactant, water and an organic solvent component comprising a predominately normal or straight chain ethylene glycol pentyl ether product containing at least about 90% by weight, based on the total weight of the ethylene glycol pentyl ether product of mono-ethylene, diethylene or triethylene glycol n-pentyl ether or mixtures thereof.
DESCRIPTION OF THE INVENTION
The water-based cleaning compositions of the present invention comprise (a) a surfactant component, (b) water and (c) a solvent component comprising an ethylene glycol pentyl ether product which contains at least about 90% by weight of mono-ethylene, diethylene or triethylene glycol n-pentyl ether. Particularly good results are obtained when the ethylene glycol pentyl ether product contains at least about 95% up to 99% or higher by weight of mono-ethylene, diethylene or triethylene glycol n-pentyl ether or mixtures thereof.
The unique properties that this specifically defined ethylene glycol n-pentyl ether product provides when used in water-based cleaning compositions have heretofore gone unrecognized in the art. The water-based cleaning compositions of applicants' invention exhibit unexpectedly improved cleaning efficiency compared to other glycol ethers while offering other properties necessary for commercial acceptance including acceptable odor characteristics and low toxicity.
In particular, it has been discovered that the water solubility of the ethylene glycol n-pentyl ether product used in the water-based cleaning compositions of the present invention is greater than expected and that suprisingly, its cleaning efficiency continues to increase as its concentration in a water-based cleaning composition increases to the saturation point, thus providing water-based cleaning compositions with cleaning efficiencies significantly superior to any previously known in the art. This effect is not seen with, for example, ethylene glycol butyl ether or ethylene glycol hexyl ether whose cleaning efficiency quickly passes through a maximum and then declines as concentration is increased. This suprising beneficial feature of the ethylene glycol n-pentyl ether solvent of the present invention allows the formulator to tune the cleaning performance of the cleaning compositions of the present invention by changing solvent concentration and to more easily balance cleaning performance with other desirable properties. The presence of higher amounts of the normal pentyl species in the ethylene glycol n-pentyl ether product used in the water-based cleaning compositions of the present invention, in addition to improving cleaning efficiency, results in other benefits such as better odor characteristics, less streaking, better cloud point control and low toxicity.
The ethylene glycol n-pentyl ether product containing at least about 90% by weight of mono-ethylene, diethylene or triethylene glycol n-pentyl ether may be obtained using known, processes and techniques. Such products are advantageously prepared by reacting pentanol containing at least about 90% n-pentanol with ethylene oxide in the presence of a basic or acidic catalyst until a product of the desired molec
Christensen Scott Patrick
Derstine Christopher W.
Keen Brian T.
Gupta Yogendra N.
Mruk Brian P.
Union Carbide Chemicals & Plastics Technology Corporation
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