Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2001-09-24
2004-05-04
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S444000, C510S446000, C510S470000, C510S475000
Reexamination Certificate
active
06730652
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to liquid automatic dishwashing detergent compositions. More particularly, the invention relates to a process for making colored particles that can be incorporated into a bleach-containing or non-bleach-containing liquid automatic dishwashing detergent composition for improving the aesthetics of the liquid composition wherein the colored particles do not stain the plastic surfaces of dishware or an automatic dishwasher.
BACKGROUND OF THE INVENTION
Consumers of liquid ADW products have a preference for such products having a certain color or appearance. The addition of solid particles suspended into a liquid ADW composition can improve the aesthetics of the product by simply improving the physical appearance of the product. This is particularly true if the particles are colored and their color is matched effectively to the base color of the liquid ADW composition.
Previously used particles in liquid ADW products have had a major disadvantage of contributing negatively to unwanted filming, particularly on glass, stainless steel and plastic surfaces. This is because the previously used particles have been coated with water-insoluble coatings, such as waxes, which melt and are released into the wash solution due to the high temperature encountered during the automatic dishwashing process.
Further, in the arena of bleach containing liquid ADWs, the particles cannot be colored by simply using a dye, because during storage of the liquid ADW product, the dye gets bleached. Thus, the formulators have to use bleach-safe pigments to impart an aesthetically pleasing color. Before this invention, the incorporation of pigments posed a major problem: the color of the pigment is found to detrimentally stain plastic surfaces, such as plastic dishware and the internal plastic surfaces of a dishwasher.
It has been desirable to have a process by which colored pigment based particles can be made for incorporation in bleach-containing or non-bleach-containing liquid ADW product, such that the particles are non-staining. It has also been desirable that the solid particles do not dissolve in the liquid ADW product, but dissolve rapidly in the wash solution during automatic dishwashing. It has been desirable to have a liquid ADW product having solid particles that do not cause a significant amount of unwanted filming on glass, stainless steel and plastic.
The inventors of the present invention have discovered a process of coating the particles with a pigment in a manner such that the particles are non-staining. This invention is not limited to just bleach-containing liquid ADWs and is also applicable to non-bleach-containing liquid ADWs that are incorporated with prills or particles colored with pigments. The present invention is thus directed to overcome one or more of the problems as set forth before.
SUMMARY OF THE INVENTION
The invention meets the needs above by providing a process for forming a non-staining colored composite particle suitable for incorporation in a bleach-containing or non-bleach-containing liquid detergent composition, a non-staining colored composite particle and a liquid dishwashing detergent composition.
In one aspect of the present invention, the process includes the steps of forming a colored liquid dispersion of pigment particles in a first liquid medium. The size of the pigment particles in the colored liquid dispersion is no greater than about 5 &mgr;m. The process includes the step of mixing the colored liquid dispersion with a polymeric material and a second liquid medium to form a sprayable colored polymeric material. The polymeric material being selected from the group consisting of alkyl cellulose ethers and polyvinyl alcohol. The process also includes the step of spraying the colored polymeric material on a composite particle and forming a colored polymeric coating on the composite particle.
In another aspect of the present invention, a non-staining colored composite particle suitable for incorporation in a bleach-containing liquid detergent composition is disclosed. The particle is made by the process as set forth above.
In yet another aspect of the present invention, a liquid automatic dishwashing detergent product is disclosed. The product includes a liquid dishwashing detergent composition containing chlorine bleach, and non-staining colored composite particles. The particles are made by the process as set forth above.
DETAILED DESCRIPTION OF THE INVENTION
In the preferred embodiment of the present invention, the process includes the steps of forming a colored liquid dispersion of pigment particles in a first liquid medium.
Pigment Processing
The size of the pigment particles in the colored liquid dispersion is desirably no greater than about 5 &mgr;m. preferably no greater than about 1 &mgr;m, more preferably no greater than about 0.1 &mgr;m, and most preferably no greater than about 0.01 &mgr;m. It has been surprisingly discovered that when the pigment particle size in the pigment-liquid dispersion is maintained within the above size limitations, the resultant pigment, when deposited on a particle as a part of the sprayable polymeric slurry, is essentially non-staining. i.e., its color does not transfer onto plastic surfaces. The selection of the pigment particle size is the key to the present invention. One skilled in the art can apply other means for achieving a pigment particle size in the size limitation as disclosed above.
In the preferred embodiment, the first liquid medium is preferably water. Optionally, a minor amount of a nonionic surfactant is added to the water to improve the dispersion of the pigment. Typically, this surfactant is added in an amount no greater than about 10% by weight.
In the preferred embodiment, the process includes the step of maintaining the amount of surfactants used in the bleach-containing liquid detergent composition at a preselected value such that when the bleach-containing liquid detergent composition is diluted in a wash solution, the amount of surfactant delivered in the wash solution is less than critical micelle concentration. The term “critical micelle concentration” is well known to those skilled in the art and need not be explained any further for purposes of brevity.
Polymeric Coating
In the preferred embodiment, the colored polymeric coating is insoluble in the liquid automatic dishwashing detergent composition but soluble in automatic dishwashing wash solution. The coating is prepared from materials which are insoluble in the liquid automatic dishwashing detergent composition but soluble in automatic dishwashing wash solution. The coating is prepared from materials selected from the group consisting of alkyl cellulose ethers and polyvinyl alcohol. Alternatively, the coating is prepared from alginate. Desirably, the alkyl cellulose ethers are selected from one of methyl cellulose and hydroxypropyl methyl cellulose (HPMC). Preferably, the coating is prepared from methyl cellulose having a number average molecular weight desirably in a range of from about 5000 to about 100,000, more preferably from about 10,000 to about 20,000, and most preferably, about 14,000. The preferred methyl cellulose is one sold under the trade name Methocel A15LV, and manufactured by Dow Chemicals. Alternatively, the polymeric coating is polyvinyl alcohol (PVA) having a molecular weight, desirably in a range of from about 5000 to about 100,000, and preferably from about 13,000 to about 23,000. The preferred PVA is from about 87% to about 89% hydrolyzed, such as a commercially available product having a trade name Airvol 205. Further, the particles are insoluble in the liquid automatic dishwashing detergent composition and only soluble in the wash solution during automatic dishwashing.
Process for Spraying Colored Polymeric Coating on Particles
The process by which the colored polymeric coating is prepared and deposited upon the particle is critical in order for the particles to remain undissolved in the liquid automatic dishwashing detergent composition and only become soluble in
Foley Peter Robert
Leyendecker Mary Ruth
Painter Jeffrey Donald
Sadlowski Eugene Steven
Song Brian Xiaoqing
Hardee John
The Procter & Gamble & Company
Waugh Kevin L.
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