Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-09-08
2003-02-18
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S476000
Reexamination Certificate
active
06521576
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to a composition for use in a dishwashing machine. More particularly, the invention is directed to a superior dishwashing composition that has a hydrophobically modified polycarboxylic acid and a water soluble polymer that reduces phosphate scale formation. The dishwashing composition unexpectedly results in excellent cleaning properties and excellent glass appearance when used to clean glassware even in the presence of hard water and in the absence of conventional rinse aid compositions.
BACKGROUND OF THE INVENTION
Dishwashing compositions constitute a generally recognized distinct class of detergent compositions, particularly when compared to detergents designed for fabric washing. For example, the ultimate dishwashing composition results in a spotless and film-free appearance on glassware and silverware after a cleaning cycle in a dishwashing machine. In fabric washing operations, on the otherhand, detergent compositions which result in greasy, oily or soapy residues on items that were cleaned can be tolerated.
Often, washing articles in a commercially available dishwashing machine entails using three products. Salt is added to the salt compartment to recharge the ion exchanger which softens the water, a dishwashing formulation is used to clean the articles and a rinse aid is used to ensure that the articles are rinsed with no streaks or smears. Consumers generally find it very inconvenient, however, to replace or refill such products.
In order to provide convenient products to consumers, manufacturers have been making dishwashing tablets in order to eliminate detergent handling and dosing issues. Such tablets often have a detergent portion, and a wax portion which contains a rinse aid. These types of tablets, which are sometimes referred to as 2-in-1 tablets, have disadvantages since they may only be used in a wash cycle that does not exceed 55° C. This is true because the wax portion which contains the rinse aid will completely dissolve in a wash cycle that exceeds 55° C. This causes all of the rinse aid to drain out of the dishwashing machine before the actual rinse cycle. Furthermore, such 2-in-1 tablets require that salt be added to the dishwashing machine in order to obtain optimal results, and they are very complicated and expensive to produce.
Other types of tablets that are well known are often referred to as pH sensitive 2-in-1 tablets . These types of tablets have a detergent portion and rinse aid portion that is contained in a pH sensitive material. The pH sensitive 2-in-1 tablets may be used in wash cycles that exceed 55° C. However, like the detergent tablets with the wax portion, the pH sensitive 2-in-1 tablets require that salt be added to the dishwashing machine in order to obtain optimal cleaning results and they are extremely expensive to produce.
In view of the vast deficiencies of the conventional products, it is of increasing interest to provide a dishwashing composition, such as a dishwashing tablet, that works well at all wash temperatures of a dishwashing system (even temperatures greater than 55° C.), provides antiscaling benefits in a system that is high in phosphate content (in hard water), does result in excellent cleaning benefits in water that has not been subjected to conventional water softening additives (i.e., hard water) and provides a glossy glassware appearance in the absence of conventional rinse aid compositions. This invention, therefore, is directed to a dishwashing composition that has a hydrophobically modified polycarboxylic acid and a water soluble polymer that reduces phosphate scale formation on glassware being cleaned. The dishwashing composition is superior in that it unexpectedly results in excellent cleaning properties, and reduced spotting and scale formation even when no salt is added to the dishwashing machine to soften hard water, when washing cycles exceed a temperature of 55° C., and when no rinse aid composition is added to the dishwashing machine. In fact, the present invention is directed to a superior 3-in-1 detergent composition that is inexpensive to produce and very easy for the consumer to use.
BACKGROUND MATERIAL
Efforts have been made to prepare dishwashing compositions. In U.S. Pat. No. 5,939,373, an automatic dishwashing detergent composition comprising a phosphate builder and a metal containing bleach catalyst is described.
Still other efforts have been disclosed for making dishwashing compositions. In WO 00/06688, a dishwashing composition with a coated core is described. The coated core has a substance that exerts function in a clear rinse cycle.
Even further, other efforts have been disclosed for making dishwashing compositions. In DE 197 27 073 A1, coated detergent components are described.
None of the material above describes a dishwashing composition that has a hydrophobically modified polycarboxylic acid and a water soluble polymer that reduces phosphate scale formation wherein the dishwashing composition results in excellent cleaning properties and glass appearance when used, for example, in the presence of hard water, in the absence of rinse aid compositions and even in a washing cycle that exceeds a temperature of 55° C.
SUMMARY OF THE INVENTION
In a first aspect, the present invention is directed to a hard water dishwashing composition effective for cleaning and reducing spotting and phosphate scale formation on glassware, the dishwashing composition comprising:
a) a hydrophobically modified polycarboxylic acid; and
b) a water soluble polymer that reduces phosphate scale formation.
In a second aspect, this invention is directed to a method for minimizing spotting and phosphate scale formation on glassware being cleaned, comprising the steps of:
a) subjecting the glassware to a dishwashing composition comprising a hydrophobically modified polycarboxylic acid, and a water soluble polymer that reduces phosphate scale formation;
b) subjecting the glassware to hard water; and
c) removing the glassware from the hard water
wherein the glassware is not subjected to a rinse aid composition.
In a third aspect, this invention is directed to a package comprising the dishwashing composition described in the first aspect of this invention and instructions not to use a rinse aid composition or conventional water softening salts or both.
As used herein, glassware is defined to include drinking glasses and any other articles typically found in a commercial or domestic dishwasher.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As used in this invention, a hydrophobically modified polycarboxylic acid is defined to mean a compound, oligomer or polymer having at least one carboxylic acid group and at least one group that is not water soluble. There generally is no limitation with respect to the type of hydrophobically modified polycarboxylic acid that may be used in this invention other than that the polycarbocylic acid can be used in a dishwashing composition that comprises a water soluble polymer that reduces phosphate scale formation. Such a hydrophobically modified polycarboxylic acid often has a weight average molecular weight of greater than about 175 and less than about 1.5 million, and preferably, greater than about 200 and less than about 1 million; and most preferably, greater than about 225 and less than about 750 thousand, including all ranges subsumed therein.
The preferred hydrophobically modified polycarboxylic acid which may be used in this invention comprises at least one structural unit of the formula:
wherein each R
1
and R
2
are independently a hydrogen, hydroxy, alkoxy, carboxylic acid group, carboxylic acid salt, ester group, amide group, aryl, C
1-20
alkyl, C
2-20
alkenyl, C
2-20
alkynyl or a polyoxyalkylene condensate of an aliphatic group, n is an integer from about 0 to 8, z is an integer from about 1 to about 8, t is an integer from about 0 to about 2,000 and a is an integer from about 0 to about 2,000, with the proviso that a and t are not simultaneously 0 and at least one R
1
or one R
2
is a carboxylic acid group, or a salt
Chiou Yu-Min Catherine
Ghatlia Naresh Dhirajlal
Hardee John
Koatz Ronald A.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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