Background of the Invention Many hard surface cleaning compositions have been disclosed in the literature and a large 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 which may be chosen by the skilled formulator.

It is well known that an organic solvent needs to be present in water-based cleaning compositions to achieve acceptable results in cleaning hard surfaces such as glass. 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. Recent regulatory efforts to reduce exposure to volatile organic compounds have caused the industry to look for more efficient solvent systems for cleaning compositions.

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, U. S. Patent No.

3,882,038 discloses hard surface cleaning compositions containing certain classes of glycol ether compositions including those represented by the formula: RO (C2H40) 4H wherein R is an alkyl group containing from 5 to 8 carbon atoms, and u has a value of from 1 to 6, preferably 1 to 3, with the proviso that R has a value of from 1 to 4 when R contains five carbon atoms, and u has a value of 3 to 6 when R contains from 6 to 8 carbon atoms. Other patents disclosing cleaning compositions having solvent systems containing glycol ethers alone or in combination with other organic solvents include U. S. Pat. Nos. 3,463,735; 4,540,505; 4,749,509; 4,863,629; 4,983,317; 5,437,807; 5,538,664 and 5,750,482.

Summary of the Invention According to the present invention, applicants have discovered a specific ethylene glycol pentyl ether product which is a useful component in 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. The specific ethylene glycol pentyl ether product has unique cleaning properties when used in water- based cleaning compositions which has heretofore gone unrecognized in the art. The particular ethylene glycol pentyl ether product which applicants have discovered exhibits unexpectedly good cleaning efficiency as well as other advantageous properties such as increased water solubility and lower vapor pressure when used in cleaning compositions, and in particular water-based hard surface cleaning compositions, is 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 product of mono-ethylene, diethylene or triethylene glycol n-pentyl ether. In particular, it has been discovered that the water solubility of the ethylene glycol pentyl ether product used in the 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. This is an effect not seen with known cleaning composition solvents such as ethylene glycol butyl ether or ethylene glycol hexyl ether whose cleaning efficiency quickly passes through a maximum and then declines with increasing concentration. This beneficial feature of the ethylene glycol pentyl ether product 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 pentyl ether product used in the cleaning compositions of the present invention, in addition to improving cleaning efficiency, has been found to provide other benefits such as better odor characteristics.

Particularly good results are obtained when the ethylene glycol pentyl ether product contains at least about 95% by weight of mono-ethylene, diethylene or triethylene glycol n-pentyl ether or mixtures thereof.

The ethylene glycol 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 molecular weight is obtained. Pentanol containing at least about 90% n-pentanol may be prepared directly utilizing oxo technology disclosed in U. S. Patent Nos. 3,527,809; 4,283,562; 4,593,011; 4,762,817; 4,769,498; 5,113,022; 5,180,854 and 5,364,950 or by refining a pentanol product containing more than 10% isomers. The ethylene glycol pentyl ether product used in the water-based cleaning compositions of the present invention contains minor amounts, i. e. less than 10%, of the 2-methylbutyl isomer but is otherwise essentially free of isomers including highly toxic species such as the 3-methylbutyl species.

The amount of the ethylene glycol pentyl ether prodsuct used in the water-based cleaning compositions of the present invention will vary depending on the type and amount of other ingredients present.

The amount of the ethylene glycol pentyl ether used to achieve an optimum balance between cleaning efficiency and other properties such as cloud point while minimizing the overall amount of volatile organic compounds present can readily be determined by the skilled formulator. Typically, the ethylene glycol pentyl ether product will be present in an amount of from about 0.05 to about 10.0% by weight, based on the total weight of the cleaning composition. Particularly good results are obtained using up to about 3.0% by weight of the mono-ethylene glycol n-pentyl ether product in the cleaning compositions of the present invention alone or in combination with other solvents.

The water-based cleaning compositions of the present invention may contain other organic solvents in addition to the ethylene glycol pentyl ether product. Suitable compounds which may be useful as cosolvents are well known and may be selected from alcohols, glycols, glycol ethers, glycol ether esters, ketones, esters, and the like.

Examples of such compounds include, without limitation, ethanol, propanol, isopropanol, butanol, glycol, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, propylene glycol t-butyl ether and mixtures thereof.

Surfactants useful in the cleaning compositions of the present invention are well known and include anionic, nonionic and amphoteric compounds. Examples of such compounds are disclosed in U. S. Patent Nos. 5,780,482 and 5,437,807 which are incorporated herein by reference. Combinations of more than one such surfactant compound may be used in the cleaning compositions of the present invention.

Typically, the total amount of surfactant present in the cleaning compounds of the present invention will be in the range of about 0.01 to about 5.0% by weight, based on the total weight of the composition.

The water-based cleaning compositions of this invention may include any of the well-known and conventional components used in such compositions. Such components include, for example, but without limitation, pH modifying agents, thickening agents, anti-streaking agents, buffers, builders, chelating or sequestering agents, hydrotopes, anti-microbial agents, colorants, and perfumes. Selection and use of such components is well within the capabilities of the skilled formulator.

The amount of water present in the water-based cleaning compositions of this invention will depend upon the type and amount of other components present. Typically, the amount of water used in such compositions will be in the range of about 50 to about 99% by weight, based on the total weight of the composition. Selection of the appropriate amount of water and the manner in which the various components are combined to prepare the cleaning compositions of this invention are within the skill of a knowledgeable formulator.

Examples A series of hard surface cleaning compositions containing a surfactant component, a solvent component and water were prepared and tested for cleaning performance and cloud point. The surfactant component of all of the compositions tested was 0.5% by weight of TRITON@ X-100 surfactant marketed by Union carbide Corporation.

The compositions tested contained varying amounts of the solvent component as shown in Table 1. The solvent component of the compositions representing the present invention is ethylene glycol pentyl ether (EGPE) containing 99% by weight of ethylene glycol n- pentyl ether. These compositions are compared in Table 1 with compositions having ethylene glycol butyl ether (EGBE) and ethylene glycol hexyl ether (EGHE) as solvent components.

Cleaning performance of the various compositions in Table 1 was determined by the procedures described in European Patent Application no. 506087. The cloud point of the various compositions in Table 1 was determined using the Mettler Toledo FP900 System (FP90 Central Processor and FP81 Measuring Cell) for the measurements of temperature transitions. The control standard is based on a cleaning composition containing 2.5% by weight ethylene glycol butyl ether (Butyl CELLOSOLVE (g)), 0.5% TERGITOL@ Nonionic Surfactant NP-9 and water.

Table 1 Comp. Solvent Cleaning Performance Cloud Point (Control = 1.0) Temp. (°C) 1 0.5% EGPE 1.17 62 2 1.0% EGPE 1.18 55 3 1.5% EGPE 1.35 49 4 2.0% EGPE 1.46 41 5 2.5% EGPE 1.54 34 6 3.0% EGPE 1.83 27 7 1.0% EGBE 1.09 68 8 2.0% EGBE 1.09 69 9 3.0% EGBE 1.12 68 10 4.0% EGBE 0.97 66 11 5.0% EGBE 0.87 64 12 0.5% EGHE 1.34 39 13 0.75% EGHE 1.42 25 14 1.0% EGHE 1.27 16 From the data in Table 1, it can be seen that the cleaning performance of compositions 1 to 6, which represent the compositions of the present invention, increase steadily with increased solvent concentration.