Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1998-12-23
2001-08-21
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S337000, C510S338000, C510S372000, C510S418000, C510S426000
Reexamination Certificate
active
06277804
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for preparing liquid laundry detergent products which are non-aqueous in nature and which are in the form of stable dispersions of particulate material such as bleaching agents and/or other detergent composition adjuvants.
BACKGROUND OF THE INVENTION
Liquid detergent products are often considered to be more convenient to use than are dry powdered or particulate detergent products. Liquid detergents have therefore found substantial favor with consumers. Such liquid detergent products are readily measurable, speedily dissolved in the wash water, capable of being easily applied in concentrated solutions or dispersions to soiled areas on garments to be laundered and are non-dusting. They also usually occupy less storage space than granular products. Additionally, liquid detergents may have incorporated in their formulations materials which could not withstand drying operations without deterioration, which operations are often employed in the manufacture of particulate or granular detergent products.
Although liquid detergents have a number of advantages over granular detergent products, they also inherently possess several disadvantages. In particular, detergent composition components which may be compatible with each other in granular products may tend to interact or react with each other in a liquid, and especially in an aqueous liquid, environment. Thus such components as enzymes, surfactants, perfumes, brighteners, solvents and especially bleaches and bleach activators can be especially difficult to incorporate into liquid detergent products which have an acceptable degree of chemical stability.
One approach for enhancing the chemical compatibility of detergent composition components in liquid detergent products has been to formulate non-aqueous (or anhydrous) liquid detergent compositions. In such non-aqueous products, at least some of the normally solid detergent composition components tend to remain insoluble in the liquid product and hence are less reactive with each other than if they had been dissolved in the liquid matrix. Non-aqueous liquid detergent compositions, including those which contain reactive materials such as peroxygen bleaching agents, have been disclosed for example, in Hepworth et al., U.S. Pat. No. 4,615,820, Issued Oct. 17, 1986; Schultz et al., U.S. Pat. No. 4,929,380, Issued May 29, 1990; Schultz et al., U.S. Pat. No. 5,008,031, Issued Apr. 16, 1991; Elder et al., EP-A-030,096, Published Jun. 10, 1981; Hall et al., WO 92/09678, Published Jun. 11, 1992 and Sanderson et al., EP-A-565,017, Published Oct. 13, 1993.
Even though chemical compatibility of components may be enhanced in non-aqueous liquid detergent compositions, physical stability of such compositions may become a problem. This is because there is a tendency for such products to phase separate as dispersed insoluble solid particulate material drops from suspension and settles at the bottom of the container holding the liquid detergent product. As one consequence of this type of problem, there can also be difficulties associated with incorporating enough of the right types and amounts of surfactant materials into non-aqueous liquid detergent products. Surfactant materials must, of course, be selected such that they are suitable for imparting acceptable fabric cleaning performance to such compositions but utilization of such materials must not lead to an unacceptable degree of composition phase separation. Phase stabilizers such as thickeners or viscosity control agents can be added to such products to enhance the physical stability thereof. Such materials, however, can add cost and bulk to the product without contributing to the laundering/cleaning performance of such detergent compositions.
It is also possible to select surfactant systems for such liquid laundry detergent products which can actually impart a structure to the liquid phase of the product and thereby promote suspension of particulate components dispersed within such a structured liquid phase. An example of such a product with a structured surfactant system is found in van der Hoeven et al.; U.S. Pat. No. 5,389,284; Issued Feb. 14, 1995, which utilizes a structured surfactant system based on relatively high concentrations of alcohol alkoxylate nonionic surfactants and anionic defloculating agents. In products which employ a structured surfactant system, the structured liquid phase must be viscous enough to prevent settling and phase separation of the suspended particulate material, but not so viscous that the pourability and dispensability of the detergent product is adversely affected.
Given the foregoing, there is clearly a continuing need to identify and provide processes for preparing liquid, particulate-containing detergent compositions in the form of non-aqueous liquid products that have a high degree of chemical, e.g., bleach and enzyme, stability along with commercially acceptable phase stability, pourability and detergent composition laundering, cleaning or bleaching performance. Accordingly, it is an object of the present invention to provide a process for preparing non-aqueous, particulate-containing liquid detergent products which have such especially desirable chemical and physical stability characteristics as well as outstanding pourability and fabric laundering/bleaching performance characteristics.
SUMMARY OF THE INVENTION
The present invention relates to a process for preparing non-aqueous liquid detergent compositions in the form of a suspension of solid, substantially-insoluble particulate material dispersed throughout a structured, surfactant-containing liquid phase. Such a process comprises the steps of
A) forming an aqueous slurry containing one or more alkali metal salts of linear C
10-16
alkyl benzene sulfonic acids (LAS) and one or more dissolved non-surfactant salts such as sodium sulfate;
B) drying the Step A slurry to a solid material containing from about 0.5% to 4% by weight of water;
C) adding, in particulate form, the dried solid material of Step B to an agitated liquid medium comprising one or more non-aqueous organic diluents such as alcohol ethoxylated surfactants and/or non-aqueous low polarity solvents, to thereby form a structured, surfactant-containing liquid phase; and thereafter
D) subjecting the structured, surfactant-containing liquid phase formed in Step C to milling or high shear agitation which is sufficient to increase the yield value of said structured, surfactant-containing liquid phase to a level within the range from 1 Pa to 8 Pa.
The aqueous slurry formed in Step A contains from about 45% to 94% by weight of the LAS salts and from about 2 to 50% by weight of the non-surfactant salt. The milling or high shear agitation of Step D is carried out at a temperature of from about 10° C. to 90° C., preferably 20° C. to 60° C.
The non-aqueous liquid detergent compositions formed by this process are effective for cleaning and bleaching of fabrics and are capable of stably suspending a variety of detergent adjuvants in the form of insoluble particulate material. Such particulate material is selected from peroxygen bleaching agents, bleach activators, ancillary anionic surfactants, organic detergent builders and inorganic alkalinity sources and combinations of these particulate material types.
DETAILED DESCRIPTION OF THE INVENTION
The non-aqueous liquid detergent compositions prepared in accordance with this invention comprise a structured, surfactant-containing liquid phase in which solid substantially insoluble particulate material is suspended. The essential and optional components of the structured liquid phase and the solid dispersed materials of the detergent compositions prepared herein, as well as composition form, preparation and use, are described in greater detail as follows: (All concentrations and ratios are on a weight basis unless otherwise specified.)
Surfactant-Structured Liquid Phase
The surfactant-containing, structured liquid phase will generally comprise from about 45% to 95% by weight of the detergent composit
Broeckx Walter A. M.
Goderis Iwein J. M. J.
Kahn Jay I.
Smerznak Mark A.
Cook C. Brant
Miller Steven W.
Ogden Necholus
The Procter & Gamble & Company
William Zerby Kim
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