Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Cream or paste
Reexamination Certificate
2002-07-17
2004-05-25
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Cream or paste
C510S424000, C510S426000, C510S499000, C510S500000
Reexamination Certificate
active
06740630
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to processes for making soluble, preferably water-soluble, substantially anhydrous surfactant pastes and other detergent ingredients, products formed by such processes and compositions comprising such substantially anhydrous surfactant pastes and/or other detergent ingredients. More particularly, the present invention relates to a process for making substantially anhydrous surfactant pastes which at room temperature are shear thinning non-Newtonian pastes with a yield point suitable for agglomeration with dry detergent powder to form a granular detergent product and, alternatively, suitable for incorporation into substantially anhydrous liquid products.
BACKGROUND OF THE INVENTION
Liquid laundry detergent products offer a number of advantages over dry, powdered or particulate laundry detergent products. Liquid laundry detergent products are readily measurable, speedily dissolved in wash water, non-dusting, are capable of being easily applied in concentrated solutions or dispersions to soiled areas on garments to be laundered and usually occupy less storage space than granular products. Additionally, liquid laundry detergents may have incorporated into their formulations materials which would deteriorate in the drying operations employed in the manufacture of particulate or granular laundry detergent products. Because liquid laundry detergents are usually considered to be more convenient to use than granular laundry detergents, they have found substantial favor with consumers.
Although liquid laundry detergents have a number of advantages over granular laundry detergent products, there are also disadvantages entailed in using them. In particular, laundry 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. Components such as surfactants, perfumes, brighteners and non-aqueous solvents can be especially difficult to incorporate into liquid laundry detergent products with an acceptable degree of compositional stability. Poor compositional stability may cause the detergent composition to deteriorate into an unaesthetic, ineffective, heterogeneous composition during storage.
One approach for enhancing the chemical compatibility and stability of liquid laundry detergent products has been to formulate substantially anhydrous liquid laundry detergent compositions using non-aqueous components. Generally, the chemical stability of the components of a non-aqueous liquid laundry detergent composition increases as the amount of water in the laundry detergent composition decreases. Moreover, by minimizing the amount of water in a liquid laundry detergent composition, one can maximize the surfactant activity of the composition. Non-aqueous liquid laundry detergent compositions have been disclosed 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.
But, non-aqueous liquid laundry detergents come with their own set of disadvantages and problems. The desirable advantage of having excellent compositional stability may also mean that the non-aqueous liquid laundry detergent will have poor solubility and dispersion properties in the wash liquor in an automatic clothes washer. Also, non-aqueous liquids typically have awkward rheological properties, displaying a tendency known as “shear thickening”, whereby the viscosity of the paste or liquid increases with an increasing shear rate, making the paste difficult to pump, store and/or transport. Moreover, non-aqueous liquid laundry detergent compositions are difficult and expensive to manufacture. A drying step requiring prolonged heating and stirring is usually necessary to eliminate the water. Not only is it difficult to consistently achieve the proper heating and stirring conditions in a manufacturing setting, but also such drying operations may have the effect of decomposing or evaporating individual components of the detergent composition. The resulting difficulty and expense involved with working with such fluids have greatly reduced their use as laundry detergent compositions.
The incorporation of surfactants into various consumer products, especially detergent products, such as granular detergent products and liquid detergent products, substantially anhydrous liquid detergent products in particular, is a common step in the manufacture of such products. However, the incorporation of such surfactants can present challenges to formulators. especially in the case of substantially anhydrous liquid products, because conventional surfactants, such as alkyl benzene sulfonate surfactants, are typically only available commercially in the form of an aqueous paste prior to being processed into the products.
Given the foregoing, there is clearly a need to provide processes for preparing anhydrous surfactant pastes for incorporation into anhydrous liquid products, as well as into granular detergent products. The resulting liquid and granular products should exhibit a high surfactant activity and should be readily soluble in a wash liquor. In addition, such processes should be easily replicated at multiple production sites and should produce liquid laundry detergent products that can be easily pumped, stored and transported.
The present invention fulfills the needs described above by providing processes for making soluble, preferably water-soluble, substantially anhydrous surfactant pastes and other detergent ingredients, products formed by such processes and compositions comprising such anhydrous surfactant pastes and/or other detergent ingredients.
SUMMARY OF THE INVENTION
The present invention encompasses a process for preparing a substantially anhydrous structured surfactant paste containing less than 5% water, comprising the steps of:
A) forming an aqueous surfactant mixture by mixing, by weight of the mixture:
(a) from about 5% to about 85%, of an anionic surfactant,
(b) from about 1% to about 60% of a water-soluble, preferably cationic, structuring agent; and
(c) from about 15%, to about 95% of an organic solvent,
wherein the aqueous surfactant mixture has a water content of 5% to about 80% by weight of the aqueous surfactant mixture; and
B) drying the aqueous surfactant mixture from step (A) under vacuum, preferably in an evaporative column, to form and structure said substantially anhydrous surfactant paste, which at room temperature (18-30° C.), is in the form of a shear thinning, non-Newtonian fluid.
In a preferred mode the anionic surfactant is selected from the group consisting of alkyl benzene sulfonates, alkyl sulfates, alkyl ethoxy sulfates, and mixtures thereof.
The preferred structuring agent used herein is an alkoxylated cationic compound, especially ethoxylated hexamethylene diamine diquats. The weight ratio of structuring agent: anionic surfactant is preferably in the range of about 1:100 to about 1:1.
In a preferred mode, the organic solvent is a member selected from the group consisting of: alkylene glycols; diethyl- and dipropylene glycol monobutyl ethers; glycol monobutyl ether; monoethylethers, monomethylethers, monopropylethers and monobutylethers of propoxy propanol; polyethylene glycols having a molecular weight of at least about 150; methyl acetate; methyl propionate; methyl octanoate; methyl dodecanoate; and mixtures thereof.
In one aspect, said aqueous surfactant mixture further comprises a nonionic surfactant typically at a weight ratio of anionic:nonionic surfactant in the range of 5:1 to 1:5. In another aspect, the aqueous surfactant mixture further comprises from about 0.001% to about 40% of additional detergency additives selected from the group comprising chelants, buffers, builders and thereof.
In another aspect, the invent
Aouad Yousef Georges
Lienhart Christopher John
Miller Steven W.
Ogden Necholus
The Procter & Gamble & Company
Zerby Kim W.
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