Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-01-23
2003-03-18
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...
C570S158000, C570S159000, C570S185000, C424S401000, 57
Reexamination Certificate
active
06534456
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates to extrudable multiphase liquid cleansing compositions of the type typically used in skin cleansing or shower gel compositions which compositions contain both “structured” lamellar and “unstructured” isotropic phase compositions.
2. Background of the Invention
Dual Phase Cleansing and Related Compositions
Compositions which both provide a cleansing function and a moisturizing benefit are known. For example, WO 90/13283 to Green, et al., published on Nov. 15, 1990; included herein by reference, discloses compositions comprising an acyl ester of an isethionic acid salt, a long chain fatty acid, a moisturizer component and optional soap.
One problem which had been previously encountered with such dual purpose compositions is that they contain an insufficient level of moisturizer component; or an insufficient amount deposits on use.
Another problem associated with such dual cleansing and moisturizing compositions is instability. According to WO 94/03152 to Helliwell, published on Feb. 17, 1994; included herein by reference, concerned with shower gels comprising a non-soap detergent, silicone oil and cationic polymers, the maximum average droplet size of the silicone oil that can be used is 2 microns, if product stability is to be maintained.
In commonly assigned U.S. Pat. No. 5,612,307 issued to Chambers, et al., on Mar. 18, 1997, included herein by reference, enhanced deposition of benefit agent was found to be obtained in a stable formulation by using a dual cleansing and moisturizing product in which the cleansing and moisturizing components were separately, but combinedly dispensed from a packaging means as discrete domains/stripes.
More specifically, the compositions of Chambers, et al. comprised a surfactant containing base formulation and a benefit agent wherein the benefit agent and base formulation were physically separate (not in direct contact) but were nonetheless dispensable from a single packaging means comprising both the base formulation and benefit agent as individual stripes. The stripes had width of at least 1000 microns and base formulation and benefit agent stripes were not post mixed prior to use (compared to EP 468,703 to Unilever where post-mixing is required).
In commonly assigned U.S. Pat. No. 5,929,019 issued to Puvvada et al., on Jul. 27, 1999; included herein by reference, the same separately dispensed, non-mixed prior to use, dual cleanser/moisturizer compositions described by Chambers, et al., is disclosed except that the benefit agent stripe had been modified so that it now may include surfactant.
Multiphase cleansing and cosmetic compositions which are not segregated in their package are also known. For example, in U.S. Pat. No. 5,059,414 issued to Dallal et al. on Oct. 22, 1991; included herein by reference, a multi-phase high viscosity cosmetic product containing two or more independent products in independent gelling matrices in single container, along with simultaneous dispensing, is described. However, Dallal describes multiphase isotropic gel products for the hair, whereas the present invention relates to a composition comprising at least one lamellar liquid and at least one isotropic liquid for personal care (hand, body and hair).
In another example, WO 9824399 to Bordat et al., published on Jun. 11, 1998; included herein by reference, describes highly viscous, separate aqueous and oil phase emulsion compositions squeezed out together as single strand from tube dispenser for use with the skin, body or hair. In comparison, the present invention uses at least one lamellar liquid and at least one isotropic liquid.
In a further example, U.S. Pat. No. 4,335,103 issued to Barker, et al., on Jun. 15, 1982: included herein by reference, describes a multiphase cosmetic composition having at least one cream or emulsion phase and one gel phase. Barker, et al., does not however disclose the stable composition of the present invention comprising at least one lamellar liquid and at least one isotropic liquid.
Lamellar Compositions
The rheological behavior of all surfactant solutions, including liquid cleansing solutions, is strongly dependent on the microstructure, i.e., the shape and concentration of micelles or other self-assembled structures in solution.
When there is sufficient surfactant to form micelles (concentrations above the critical micelle concentration or CMC), for example, spherical, cylindrical (rod-like) or discoidal micelles may form. As surfactant concentration increases, ordered liquid crystalline phases such as lamellar phase, hexagonal phase or cubic phase may form. The lamellar phase, for example, consists of alternating surfactant bilayers and water layers. These layers are not generally flat but fold to form submicron spherical onion like structures called vesicles or liposomes. The hexagonal phase, on the other hand, consists of long cylindrical micelles arranged in a hexagonal lattice. In general, the microstructure of most personal care products consist of either spherical micelles; rod micelles; or a lamellar dispersion.
As noted above, micelles may be spherical or rod-like. Formulations having spherical micelles tend to have a low viscosity and exhibit Newtonian shear behavior (i.e., viscosity stays constant as a function of shear rate; thus, if easy pouring of product is desired, the solution is less viscous and, as a consequence, it doesn't suspend as well). In these systems, the viscosity increases linearly with surfactant concentration.
Rod micellar solutions are more viscous because movement of the longer micelles is restricted. At a critical shear rate, the micelles align and the solution becomes shear thinning. Addition of salts increases the size of the rod micelles thereof increasing zero shear viscosity (i.e., viscosity when sitting in bottle) which helps suspend particles but also increases critical shear rate (point at which product becomes shear thinning; higher critical shear rates means product is more difficult to pour).
Lamellar dispersions differ from both spherical and rod-like micelles because they can have high zero shear viscosity (because of the close packed arrangement of constituent lamellar droplets), yet these solutions are very shear thinning (readily dispense on pouring). That is, the solutions can become thinner than rod micellar solutions at moderate shear rates.
In formulating liquid cleansing compositions, therefore, there is the choice of using rod-micellar solutions (whose zero shear viscosity, e.g., suspending ability, is not very good and/or are not very shear thinning); or lamellar dispersions (with higher zero shear viscosity, e.g. better suspending, and yet are very shear thinning). Such lamellar compositions are characterized by high zero shear viscosity (good for suspending and/or structuring) while simultaneously being very shear thinning such that they readily dispense in pouring. Such compositions possess a “heaping”, lotion-like appearance which convey signals of enhanced moisturization.
To form such lamellar compositions, however, some compromises have to be made. First, generally higher amounts of surfactant are required to form the lamellar phase. Thus, it is often needed to add auxiliary surfactants and/or salts which are neither desirable nor needed. Second, only certain surfactants will form this phase and, therefore, the choice of surfactants is restricted.
In short, lamellar compositions are generally more desirable (especially for suspending emollient and for providing consumer aesthetics), but more expensive in that they generally require more surfactant and are more restricted in the range of surfactants that can be used.
When rod-micellar solutions are used, they also often require the use of external structurants to enhance viscosity and to suspend particles (again, because they have lower zero shear viscosity than lamellar phase solutions). For this, carbomers and clays are often used. At higher shear rates (as in product dispensing, application of product to body, or rubbing with hands), since t
Hayward Christine
Paredes Rosa
Bornstein Alan A.
Ogden Necholus
Unilever Home and Personal Care USA division of Conopco, Inc.
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