US 20070155637 A1
A multi-phase personal cleansing composition is described that comprises a first visually distinct phase including a structured surfactant component and a second visually distinct phase comprising a benefit phase comprising an emulsion. The structured surfactant component comprises at least one branched anionic surfactant and from 0 to 10 % by weight of the first visually distinct phase, of sodium trideceth sulfate.
1. A multi-phase personal cleansing composition comprising: a first visually distinct phase comprising a structured surfactant component; and
a second visually distinct phase comprises a benefit phase comprising an emulsion;
wherein said structured surfactant component comprises at least one branched anionic surfactant and from 0 to 10%, by weight of said first visually distinct phase, of sodium trideceth sulfate.
2. The multi-phase personal cleansing composition of
3. The multi-phase personal cleansing composition of
4. The multi-phase personal cleansing composition of
5. The multi-phase personal cleansing composition of
6. The multi-phase personal cleansing composition of
7. The multi-phase personal cleansing composition of
8. The multi-phase personal cleansing composition of
9. The multi-phase personal cleansing composition of
10. The multi-phase personal cleansing composition of
11. The multi-phase personal cleansing composition of
12. The multi-phase personal cleansing composition of
13. The multi-phase personal cleansing composition of
14. The multi-phase personal cleansing composition of
15. The multi-phase personal cleansing composition of
16. The multi-phase personal cleansing composition of
17. The multi-phase personal cleansing composition of
(i) at least one electrolyte;
(ii) at least one amphoacetatate surfactant;
(iii) at least one ethoxylated fatty alcohol; and
wherein said first visually distinct phase is non-Newtonian shear thinning; and
wherein said first visually distinct phase has a viscosity of equal to or greater than about 3000 cps.
18. The multi-phase personal cleansing composition of
(a) said structured surfactant component further comprising:
(i) at least one nonionic surfactant having an HLB from about 3.4 to about 15.0;
(ii) at least one amphoteric surfactant; and
(b) an electrolyte.
19. The structured, multi-phase personal cleansing composition of
This application is a continuation in part of U.S. application Ser. No. 11/400,359 filed Apr. 7, 2006, pending, that claims the benefit of U.S. Provisional application Ser. No. 60/670,785 filed on Apr. 13, 2005 and U.S. Provisional application Ser. No. 60/680,114 filed on May 12, 2005 and U.S. Provisional application Ser. No. 60/680,149 filed on May 12/2005.
The present invention relates to a structured multi-phase personal cleansing composition that comprises at least one branched anionic surfactant and from 0% to 10%, by weight of the first visually distinct phase, of sodium trideceth sulfate.
Personal cleansing compositions that attempt to provide skin-conditioning benefits are known. Desirable personal cleansing compositions must meet a number of criteria. For example, in order to be acceptable to consumers, a multi-phase personal cleansing composition must exhibit good cleaning properties, must exhibit good lathering characteristics, must be mild to the skin (not cause drying or irritation) and preferably should even provide a conditioning benefit to the skin.
Many personal cleansing compositions are aqueous systems comprising emulsified conditioning oil or other similar materials in combination with a lathering surfactant. Although these products provide both conditioning and cleansing benefits, it is often difficult to formulate a product that deposits sufficient amount of skin conditioning agents on skin during use. In order to combat emulsification of the skin conditioning agents by the cleansing surfactant, large amounts of the skin conditioning agent are added to the compositions. However, this introduces another problem associated with these cleansing and conditioning products. Raising the level of skin conditioning agent in order to achieve increased deposition negatively affects the compositions speed of lather generation, total lather volume, performance and stability.
Some surfactants used in personal cleansing compositions, such as, sodium trideceth sulfate and similarly homologous chemicals based on tridecanol, also may depress the speed of lather production, although such compositions provide relatively mild cleansing. It is believed that the high level of branching in tridecanol-based surfactants and compositions that comprise them, exhibits less flash lather as a result of their water solubility. Moreover, sodium trideceth sulfate and similar homologues based on tridecanol, are relatively costly materials, as such, the compositions do not enjoy broad commercial use.
Accordingly, the need still remains for body wash composition that provides cleansing with increased lather longevity and improved lathering characteristics, and skin benefits such as silky skin feel, improved soft skin feel, and improved smooth skin feel. It is desirable to formulate compositions comprising lower levels, or even no sodium trideceth sulfate, which have the same beneficial properties as high sodium trideceth sulfate compositions.
The present invention relates to a multi-phase personal cleansing composition that comprises a first visually distinct phase comprising a structured surfactant component; and a second visually distinct phase that comprises a benefit phase that comprised an emulsion. The structured surfactant component comprises at least one branched anionic surfactant and from 0% to 10%, by weight of the first visually distinct phase, of sodium trideceth sulfate.
The inventors believe that mixtures of branched and linear anionic surfactants can provide good mildness, structure, and higher flash lather volume than compositions that comprise sodium trideceth sulfate, as the only anionic surfactant. Sufficient mildness can be provided by the highly branched tridecanol-based anionic surfactant complemented by high flash lather volume from linear structured surfactant components. These properties can be accomplished in the same composition by blending sodium trideceth sulfate with surfactants having a higher proportion of linear surfactants than sodium trideceth sulfate or by selecting surfactant which naturally have less branching than sodium trideceth sulfate. A preferred surfactant component comprises a substantial level of mono-methyl branched surfactants leading to structure and stability of structure.
The term “ambient conditions” as used herein, refers to surrounding conditions at one (1) atmosphere of pressure, 50% relative humidity, and 25° C.
By the term “multi-phase” as used herein, is meant that the phases of the present compositions occupy separate but distinct physical spaces inside the package in which they are stored, but are in direct contact with one another (i.e., they are not separated by a barrier and they are not emulsified or mixed to any significant degree). In one preferred embodiment of the present invention, the “multi-phase” personal cleansing compositions comprise at least two visually distinct phases which are present within the container as a visually distinct pattern. The pattern results from the combination of the “multi-phase” composition by a process herein described. The “patterns” or “patterned” include but are not limited to the following examples: striped, marbled, rectilinear, interrupted striped, check, mottled, veined, clustered, speckled, geometric, spotted, ribbons, helical, swirl, arrayed, variegated, textured, grooved, ridged, waved, sinusoidal, spiral, twisted, curved, cycle, streaks, striated, contoured, anisotropic, laced, weave or woven, basket weave, spotted, and tessellated. Preferably the pattern is selected from the group consisting of striped, geometric, marbled, and combinations thereof.
In a preferred embodiment, the pattern may be relatively uniform across the dimension of the package; however, the pattern may be uneven, wavy, or non-uniform in dimension and does not extend across the entire dimension of the package. If striped, the size of the stripes can be at least about 0.1 mm in width and 10 mm in length, preferably at least about 1 mm in width and at least 20 mm in length as measured from the package exterior. The phases may be various different colors, and/or include particles, glitter or pearlescent agents in at one of the phases in order to offset its appearance from the other.
The term “multi-phase personal cleansing composition” as used herein, refers to compositions intended for topical application to the skin or hair. Preferably, the compositions of the present invention are rinse-off formulations, in which the product is applied topically to the skin or hair and then is subsequently rinsed within minutes from the skin or hair with water, or otherwise wiped off using a substrate with deposition of a portion of the composition. The compositions also may be used as shaving aids.
The term “stable” as used herein, unless otherwise specified, refers to compositions that maintain at least two “separate” phases when sitting in undisturbed physical contact at ambient conditions for a period of at least about 180 days wherein the distribution of the two phases in different locations in the package does not significantly change over time. Compositions of the present invention, preferably exhibit enhanced stability, in that the first visually distinct phase has greater than 50% Viscosity Retention measured according to the T-Bar method disclosed in herein.
The term “structured surfactant component” as used herein means the total of all anionic, nonionic, amphoteric, zwitterionic and cationic surfactants in a phase. When calculations are based on the structured surfactant component, water and electrolyte are excluded from the calculations involving the structured surfactant component, since surfactants as manufactured typically are diluted and neutralized.
The term “structured,” as used herein means having a rheology that confers stability on the multi-phase composition. The degree of structure is determined by characteristics determined by one or more of the following methods the Yield Stress Method, or the Zero Shear Viscosity Method or by the Ultracentrifugation Method, all in the Test Methods below. Accordingly, a surfactant phase of the multiphase composition of the present invention is considered “structured,” if the surfactant phase has one or more of the following properties described below according to the Yield Stress Method or the Zero Shear Viscosity Method or by the Ultracentrifugation Method. A surfactant phase is considered to be structured, if the phase has one or more of the following characteristics:
As used herein “substantially free” means that the composition or phase comprises less than about 5%, preferably less than 3%, preferably less than about 1%, more preferably less than about 0.5%, more preferably less than about 0.25%,and most preferably less than about 0.1%, by weight of the composition or phase of a stated ingredient.
The term “visually distinct phase” as used herein, refers to a region of the multi-phase personal cleansing composition having one average composition, as distinct from another region having a different average composition, wherein the regions are visible to the unaided naked eye. This would not preclude the distinct regions from comprising two similar phases where one phase could comprise pigments, dyes, particles, and various optional ingredients, hence a region of a different average composition. A phase generally occupies a space or spaces having dimensions larger than the colloidal or sub-colloidal components it comprises. A phase may also be constituted or re-constituted, collected, or separated into a bulk phase in order to observe its properties, e.g., by centrifugation, filtration or the like.
Product Form: The multi-phase personal cleansing composition of the present invention is typically extrudable or dispensable from a package. The multi-phase personal cleansing compositions typically exhibit a viscosity of from about 1,500 centipoise (cP) to about 1,000,000 cP, as measured by the Viscosity Method as described in copending application serial number 10/841174 filed on May 7, 2004 titled “Multi-phase Personal Care Compositions.”
When evaluating a structured multi-phase personal cleansing composition, by the methods described herein, preferably each individual phase is evaluated prior to combining, unless otherwise indicated in the individual methodology. However, if the phases are combined, each phase can be separated by centrifugation, ultracentrifugation, pipetting, filtering, washing, dilution, concentration, or combination thereof, and then the separate components or phases can be evaluated. Preferably, the separation means is chosen so that the resulting separated components being evaluated is not destroyed and the composition and distribution of components therein is not substantially altered by the separation means, so that it is representative of the component as it exists in the structured multi-phase personal cleansing composition.
Phases: The multi-phase personal cleansing compositions of the present invention comprise at least two phases, but the compositions, a third phase, a fourth phase and so on. The ratio of a first phase to a second phase is preferably from about 1:99 to about 99:1, preferably from about 90:10 to about 10:90, more preferably from about 80:20 to about 20:80, even more preferably from about 70:30 to about 30:70, still even more preferably from about 60:40 to about 40:60, even still even more preferably about 50:50.
First Visually Distinct Phase: The first visually distinct phase of a multi-phase personal cleansing composition of the present invention can comprise a structured surfactant component. The structured surfactant component a mixture of surfactants and comprises at least of branched anionic surfactant and from 0 to 10% by weight of the first visually distinct phase, of sodium trideceth sulfate. The structured surfactant component typically comprises from about 1% to about 99%, and more preferably from about 20% to about 50%, by weight of the composition, of the first visually distinct phase.
Structured surfactant component: The multi-phase personal cleansing composition preferably comprises a structured surfactant component at concentrations ranging from about 2% to about 23.5%, more preferably from about 3% to about 21%, even more preferably from about 4% to about 20.4%, still more preferably from about 5% to about 20%, still even more preferably from about 13% to about 18.5%, and even still even more preferably from about 14% to about 18%, by weight of the first visually distinct phase.
The first visually distinct phase typically provides a Total Lather Volume of at least about 600 ml, preferably greater than about 800 ml, more preferably greater than about 1000 ml, even more preferably greater than about 1200 ml, and still more preferably greater than about 1500 ml, as measured by the Lather Volume Test described hereafter. The first visually distinct phase preferably has a Flash Lather Volume of at least about 300 ml, preferably greater than about 400 ml, even more preferably greater than about 500 ml, as measured by the Lather Volume Test described herein.
The first visually distinct phase comprising the structured surfactant component is preferably a structured domain comprising surfactants. The structured domain enables the incorporation of high levels of benefit components in a separate phase that are not emulsified in the composition. In a preferred embodiment, the structured domain is an opaque structured domain which is preferably a lamellar phase that preferably produces a lamellar gel network. The lamellar phase can provide resistance to shear, adequate yield to suspend particles and droplets and at the same time provides long term stability, since it is thermodynamically stable. The lamellar phase tends to have a higher viscosity thus minimizing the need for viscosity modifiers.
The structured surfactant component preferably comprises a lathering surfactant or a mixture of lathering surfactants. The structured surfactant component comprises surfactants suitable for application to the skin or hair which are otherwise compatible with the other essential ingredients in the multi-phase personal cleansing composition including water. Suitable surfactants are described in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; and McCutcheon's, Functional Materials, North American Edition (1992); and in U.S. Pat. No. 3,929,678 issued to Laughlin, et al on Dec. 30, 1975. These surfactants include anionic, nonionic, cationic, zwitterionic, amphoteric surfactants, soap, or combinations thereof.
Preferably, anionic surfactant comprises at least 40% of the structured surfactant component, more preferably from about 45% to about 95% of the structured surfactant component, even more preferably from about 50% to about 90%, still more preferably from about 55% to about 85%, and even still most preferably at least about 60% of the structured surfactant component comprises anionic surfactant which may be linear or branched. The first visually distinct phase or structured surfactant component preferably comprises at least one branched anionic surfactant. A surfactant molecule is branched when the hydrocarbon tail of the surfactant molecule comprises at least one ternary or quaternary carbon atom, such that a methyl, ethyl, propyl, butyl, pentyl or hexyl side chain extends from the hydrocarbon backbone. The hydrocarbon backbone is described by the longest hydrocarbon length in the hydrocarbon tail. A side chain in the branched hydrocarbon of a surfactant molecule can be described by its position on the backbone, counting from the first carbon attached to a hydrophilic atom, enumerated as carbon number 1, the adjacent carbon on the backbone being carbon number 2, and so on. Side chains are also described by their length, a single carbon side chain denoted methyl; a 2-carbon length denoted ethyl, and so on. Side chains that have their own branching are denoted by conventional nomenclature techniques, e.g., isopropyl, but are less common. Anionic surfactant molecules which do not have branching are linear anionic surfactant molecules, and surfactants comprising a preponderance of linear anioinic surfactant molecules as indicated hereafter are linear anionic surfactants. Preferred linear anionic surfactants for use in the structured surfactant phase of the multi-phase, personal cleansing composition include ammonium lauryl sulfate, ammonium laureth sulfate, sodium lauryl sulfate, sodium laureth sulfate, potassium laureth sulfate, sodium lauryl sarcosinate, sodium lauroyl sarcosinate, lauryl sarcosine, cocoyl sarcosine, ammonium cocoyl sulfate, potassium lauryl sulfate, and combinations thereof.
Because an anionic surfactant typically comprises a mixture of different types of surfactant molecules, anionic surfactants can be called linear or branched depending on the relative amounts of individual surfactant molecules of different types that comprise the anionic surfactant. For example, sodium tridecyl sulfate and sodium trideceth sulfate can be called branched surfactants because they typically comprise nearly all (>95%) branched surfactant molecules. For the purposes of the present invention, an anionic surfactant is considered branched surfactant when at least 10% of its hydrocarbon chains are branched molecules. Branching information for many surfactants is typically known or obtainable from suppliers of branched alcohol feedstocks and described in commonly owned U.S. patent application Ser. No. 60/680,149 entitled “Structured Multi-phased Personal Cleansing Compositions Comprising Branched Anioinic Surfactants”, filed on May 12, 2005, by Smith, et al.
Branched anionic surfactants include but are not limited to the following surfactants: sodium trideceth sulfate, sodium tridecyl sulfate, sodium C12-13 alkyl sulfate, sodium C12-15 alkyl sulfate, sodium C11-15 alkyl sulfate, sodium C12-18 alkyl sulfate, sodium C10-16 alkyl sulfate, sodium C12-13 pareth sulfate, sodium C12-13 pareth-n sulfate, and sodium C12-14 pareth-n sulfate. Other salts of all the aforementioned surfactants are useful, such as TEA, DEA, ammonia, potassium salts. Useful alkoxylates include the ethylene oxide, propylene oxide and EO/PO mixed alkoxylates. Phosphates, carboxylates and sulfonates prepared from branched alcohols are also useful anionic branched surfactants. Branched surfactants can be derived from synthetic alcohols such as the primary alcohols from the liquid hydrocarbons produced by Fischer-Tropsch condensed syngas, for example Safol™ 23 Alcohol available from Sasol North America, Houston, Tex.; from synthetic alcohols such as Neodol™ 23 Alcohol available from Shell Chemicals, USA; from synthetically made alcohols such as those described in U.S. Pat. No. 6,335,312 issued to Coffindaffer, et al on Jan. 1, 2002. Preferred alcohols are Safol™ 23 and Neodol™ 23. Preferred alkoxylated alcohols are Safol™ 23-3 and Neodol™ 23-3. Sulfates can be prepared by conventional processes to high purity from a sulfur based SO3 air stream process in a falling film reactor, chlorosulfonic acid process, sulfuric acid process, or Oleum process.
Monomethyl branched anionic surfactants include but are not limited to the branched anionic sulfates derived from Safol™ 23-n and Neodol™ 23-n as previously described, where n is an integer between 1 and about 20. Preferred monomethyl branched anionic surfactants include a C12-13 alkyl sulfate derived from the sulfation of Safol™ 23, which has about 28% branched anionic surfactant molecules; and a C12-13 pareth sulfate derived from Neodol™ 23-3, which has about 10-18% branched anionic surfactant molecules.
Amphoteric surfactants are suitable for use in the multi-phase composition of the present invention. The amphoteric surfactants include those that are broadly described as derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical can be straight or branched chain and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Examples of compounds falling within this definition are sodium 3-dodecyl-aminopropionate, sodium 3-dodecylaminopropane sulfonate, sodium lauryl sarcosinate, and N-alkyltaurines.
Zwitterionic surfactants suitable for use include those that are broadly described as derivatives of aliphatic quaternary ammonium, phosphonium, and sulfonium compounds, in which the aliphatic radicals can be straight or branched chain, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Zwitterionic surfactants suitable for use in the multi-phase, personal cleansing composition include betaines, including cocoamidopropyl betaine.
Non-limiting examples of preferred nonionic surfactants for use herein are those selected form the group consisting of glucose amides, alkyl polyglucosides, sucrose cocoate, sucrose laurate, alkanolamides, ethoxylated alcohols and mixtures thereof. In a preferred embodiment the nonionic surfactant is selected from the group consisting of glyceryl monohydroxystearate, isosteareth-2, trideceth-3, hydroxystearic acid, propylene glycol stearate, PEG-2 stearate, sorbitan monostearate, glyceryl laurate, laureth-2, cocamide monoethanolamine, lauramide monoethanolamine, and mixtures thereof.
Preferably the nonionic surfactant has an HLB from about 1.0 to about 15.0, preferably from about 3.4 to about 15.0, more preferably from about 3.4 to about 9.5, even more preferably from about 3.4 to about 5.0. The multi-phase personal cleansing composition preferably comprises a nonionic surfactant at concentrations ranging from about 0.01% to about 50%, more preferably from about 0.10% to about 10%, and even more preferably from about 0.5% to about 5.0%, by weight of the surfactant component.
Mixtures of anionic surfactants can be used in some embodiments, including mixtures of linear and branched surfactants, and anionic surfactants combined with nonionic, amphoteric, and/or zwitterionic surfactants.
An electrolyte, if used, can be added per se to the multi-phase personal cleansing composition or it can be formed in situ via the counterions included in one of the raw materials. The electrolyte preferably includes an anion comprising phosphate, chloride, sulfate or citrate and a cation comprising sodium, ammonium, potassium, magnesium or mixtures thereof. Some preferred electrolytes are sodium chloride, ammonium chloride, sodium or ammonium sulfate. The electrolyte is preferably added to the structured surfactant phase of the composition in the amount of from about 0.1% to about 15% by weight, preferably from about 1% to about 6% by weight, more preferably from about 3% to about 6%, by weight of the structured surfactant composition.
Non-Lathering Structured Aqueous Phase: The structured aqueous phase of the present invention can comprise from about 30% to about 99%, preferably about 50%, preferably more than about 60%, even more preferably more than about 70%, and still more preferably more than about 80%, by weight of the structured aqueous phase, of water. The structured aqueous phase will typically have a pH of from about 5 to about 9.5, more preferably about 7. A water structurant for the structured aqueous phase can have a net cationic charge, net anionic charge, or neutral charge. The structured aqueous phase of the present compositions can further comprise optional ingredients such as, pigments, pH regulators (e.g. triethanolamine), and preservatives.
The structured aqueous phase can comprise from about 0.1% to about 30%, preferably from about 0.5% to about 20%, more preferably from about 0.5% to about 10%, and even more preferably from about 0.5% to about 5%, by weight of the structured aqueous phase, of a water structurant.
The water structurant is typically selected from the group consisting of inorganic water structurants, charged polymeric water structurants, water soluble polymeric structurants, associative water structurants, and mixtures thereof. Non-limiting examples of inorganic water structurants include silicas, polymeric gellants such as polyacrylates, polyacrylamides, starches, modified starches, crosslinked polymeric gellants, copolymers, and mixtures thereof. Non-limiting examples of charged polymeric water structurants for use in the multi-phase personal cleansing composition include Acrylates/Vinyl Isodecanoate Crosspolymer (Stabylen 30 from 3V), Acrylates/C10-30 Alkyl Acrylate Crosspolymer (Pemulen TR1 and TR2), Carbomers, Ammonium Acryloyldimethyltaurate/VP Copolymer (Aristoflex AVC from Clariant), Ammonium Acryloyldimethyltaurate/Beheneth-25 Methacrylate Crosspolymer (Aristoflex HMB from Clariant), Acrylates/Ceteth-20 Itaconate Copolymer (Structure 3001 from National Starch), Polyacrylamide (Sepigel 305 from SEPPIC), and mixtures thereof. Non-limiting examples of water soluble polymeric structurants for use in the multi-phase personal cleansing composition include cellulose gums and gel, and starches. Non-limiting examples of associative water structurants for use in the multi-phase personal cleansing composition include xanthum gum, gellum gum, pectins, alginates such as propylene glycol alginate, and mixtures thereof.
Second, Visually Distinct Phase: The second visually distinct phase is distinguishable from the first visually distinct phase by having a different color, opacity may comprise a structured surfactant or may be a benefit phase comprising water in oil emulsion or an oil in water emulsion. The second visually distinct phase may comprise a structured surfactant identical to the structured surfactant or non-lathering structured aqueous phase in the first visually distinct phase; described in detail above.
The benefit phase in the present invention is preferably anhydrous and can be substantially free of water. The benefit phase can be substantially free of surfactant. The benefit phase of the present invention comprises a either a water in oil emulsion or an oil in water emulsion. In water in oil emulsions, the oil phase is the continuous phase and the water phase is the discontinuous or “internal” phase. In oil in water emulsions, the oil phase is the discontinuous phase and the water phase is the continuous or “internal” phase. As known in the art, a water in oil and oil in water emulsions comprises an aqueous phase; an oil; and an emulsifier.
The benefit phase of the present invention can comprise from about 10% to about 99%, more preferably from about 20% to about 95%, more preferably from about 50% to about 90%, and most preferably from about 60% to about 80% by weight of the benefit phase, of oil phase.
The hydrophobic materials suitable for use in the benefit phase include any natural or synthetic materials with a Vaughan Solubility Parameter of from about 5 (cal/cm3)0.5 to about 15 (cal/cm3)0.5, some non-limiting examples of such oils include following: Cyclomethicone 5.92, Squalene 6.03, Petrolatum 7.33, Isopropyl Palmitate 7.78, Isopropyl Myristate 8.02, Castor Oil 8.90, Cholesterol 9.55, as reported in Solubility Effects in Product, Package, Penetration and Preservation, C. D. Vaughan, Cosmetics and Toiletries, Vol. 103, Oct. 1988. Preferably, the hydrophobic material has an overall solubility parameter of less than about 12.5 (cal/cm3)0.5 and preferably less than 11 (cal/cm3)0.5. By “overall solubility parameter” it is meant that one can use materials with higher solubility parameter blends with other materials with lower solubility parameters to reduce the overall solubility parameter. For example, a small portion of diethylene glycol with solubility parameter of 13.61 can be blended with lanolin oil with solubility parameter of 7.3 and a co-solubilizing agent to create a mixture with a solubility parameter of less than about 12.5 (cal/cm3)0.5.
Suitable for use herein are hydrophobic materials that include, but are not limited to the group consisting of petrolatum, lanolin, hydrocarbon oils (i.e. mineral oil), natural and synthetic waxes(i.e micro-crystalline waxes, paraffins, ozokerite, lanolin wax, lanolin alcohols, lanolin fatty acids, polyethylene, polybutene, polydecene and perhydrosqualen), volatile or non-volatile organosiloxanes and oganosiloxane derivatives (i.e. dimethicones, cyclomethicones, alkyl siloxanes, polymethylsiloxanes, and methylphenylpolysiloxanes), lanolin oil, esters (i.e. isopropyl lanolate, acetylated lanolin, acetylated lanolin alcohols, lanolin alcohol linoleate, lanolin alcohol riconoleate), natural and synthetic triglycerides (i.e. castor oil, soy bean oil, sunflower seed oil, maleated soy bean oil, safflower oil, cotton seed oil, corn oil, walnut oil, peanut oil, olive oil, cod liver oil, almond oil, avocado oil, palm oil and sesame oil) and combinations thereof.
Oil in Water Emulsifier: In embodiments of the benefit phase which are a oil in water emulsion the emulsifying agent typically comprise from about 0.1% to about 10%, preferably from about 0.5% to about 5%, and more preferably from about 0.5% to about 3%, by weight of the benefit phase, of an emulsifier. Preferred oil in water emulsifiers are those that reduce the surface tension of water to not less 60 mN/m at 25° C. as measured by standard surface tension apparati and methods known to those of ordinary skill in the art, for example ASTM D1331-89 (2001) Method A, “Surface Tension”. Preferred emulsifiers exhibit a minimum surface tension in water of 60 mN/m or higher. Suitable emulsifiers promote stability of the oil in water emulsion by inhibiting coalescence of the oil droplets, and/or inhibiting phase separation of the oil and water phases.
Some suitable oil in water emulsifiers are Pemulen TR-1 (Acrylates/C10-30 Alkyl Acrylate Crosspolymer-Noveon), Pemulen TR-2 (Acrylates/C10-30 Alkyl Acrylate Crosspolymer-Noveon), ETD 2020 (Acrylates/C10-30 Alkyl Acrylate Crosspolymer-Noveon), Carbopol 1382 (Acrylates/C10-30 Alkyl Acrylate Crosspolymer-Noveon), Natrosol CS Plus 330, 430, Polysurf 67 (Cetyl Hydroxyethyl Cellulose-Hercules), Aculyn 22 (Acrylates/Steareth-20 Methacrylate Copolymer-Rohm&Haas) Aculyn 25 (Acrylates/Laureth-25 Methacrylate copolymer-Rohm&Haas), Aculyn 28 (Acrylates/Beheneth-25 Methacrylate copolymer-Rohm&Haas), Aculyn 46 (Peg-150/Stearyl Alcohol/SMDI copolymer-Rohm&Haas) Stabylen 30 (Acrylates/Vinyl Isodecanoate-3V), Structure 2001 (Acrylates/Steareth-20 Itaconate copolymer-National Starch), Structure 3001 (Acrylates/Ceteth-20 Itaconate copolymer-National Starch), Structure Plus (Acrylates/Aminoacrylates/C10-30 Alkyl Peg 20 Itaconate copolymer-National Starch, Quatrisoft LM-200 (Polyquaternium-24), the metal oxides of titanium, zinc, iron, zirconium, silicon, manganese, aluminum and cerium, polycarbonates, polyethers, polyethylenes, polypropylenes, polyvinyl chloride, polystyrene, polyamides, polyacrylates, cyclodextrins and mixtures thereof.
Other suitable emulsifiers include sub-micron organic or inorganic particles absorbed at the interface. Examples of suitable particles include micronized zeolite, fumed silica, titanium dioxide, zinc oxide, and aluminum oxide.
Water in Oil Emulsifiers: If the benefit phase is a water in oil emulsion, the benefit phase can comprise 0.1% to about 20%, more preferably from about 0.1% to about 10%, still more preferably from about 0.5% to about 9%, by weight of the benefit phase, of one or more emulsifiers.
Preferred water in oil emulsifiers of the present invention are selected from stearic acid, palmitic acid, stearyl alcohol, cetyl alcohol, behenyl alcohol, stearic acid, palmitic acid, the polyethylene glycol ether of stearyl alcohol having an average of about 1 to about 5 ethylene oxide units, the polyethylene glycol ether of cetyl alcohol having an average of about 1 to about 5 ethylene oxide units, and mixtures thereof. More preferred emulsifiers of the present invention are selected from stearyl alcohol, cetyl alcohol, behenyl alcohol, the polyethylene glycol ether of stearyl alcohol having an average of about 2 ethylene oxide units (steareth-2), the polyethylene glycol ether of cetyl alcohol having an average of about 2 ethylene oxide units, and mixtures thereof. Even more preferred emulsifiers are selected from PEG-30 Dipolyhydroxystearate, Sorbitan Oleate and mixtures thereof. When using petrolatum alone or with mineral oil we have found mixtures of anionic/amphoteric and nonionic surfactants can be used to make water in oil emulsions. These surfactants include ammonium lauryl sulfate, ammonium laureth sulfate, sodium lauryl sulfate, sodium laureth sulfate, sodium tridecyl sulfate, sodium trideceth sulfate, sodium C12-13 alkyl sulfate, sodium C12-15 alkyl sulfate, sodium C11-15 alkyl sulfate, sodium C12-18 alkyl sulfate, sodium C10-16 alkyl sulfate, sodium C12-13 pareth sulfate, sodium C12-13 pareth-n sulfate, and sodium C12-14 pareth-n sulfate, sodium 3-dodecyl-aminopropionate, sodium 3-dodecylaminopropane sulfonate, sodium lauryl sarcosinate, N-alkyltaurines, cocoamidopropyl betaine, glyceryl monohydroxystearate, isosteareth-2, trideceth-3, hydroxystearic acid, propylene glycol stearate, PEG-2 stearate, sorbitan monostearate, glyceryl laurate, laureth-2, cocamide monoethanolamine, lauramide monoethanolamine, and mixtures thereof.
Density Modifiers: The density modifiers of the present invention can be comprised in the benefit phase. Just as low density microspheres can be added to the structured surfactant component of the present invention to improve stability, high density materials can be added to the benefit component to increase its density having the same impact on stability. The high density particles employed to increase the overall density of the benefit component are particles having a density greater than 1.1 g/cm3, preferably greater than 1.5 g/cm3, more preferably greater than 2.0 g/cm3, most preferably greater than 2.5 g/cm3. The high density particles generally have a diameter less than 200 μm, preferably less than 100 μm, most preferably less than 40 μm. Preferably, the high density particles are selected from water-insoluble inorganic materials, metals, metal oxides, metal alloys and mixture thereof. Non-limiting examples include calcium carbonate, silica, clays, mica, talc, iron, zinc, copper, lead, titanium dioxide, zinc oxide, and the like.
The density modifiers can also be added to the fist visually distinct phase. To further improve stability under stress conditions such as high temperature and vibration, it is preferable to adjust the densities of the separate components or phase, such that they are substantially equal. To achieve this, low density microspheres can be added to the surfactant component or phase of the mild, structured, multi-phase cleansing composition. The low density microspheres employed to reduce the overall density of the surfactant component are particles having a density lower than 0.7 g/cm3, preferably less than 0.2 g/cm3, more preferably less than 0.1 g/cm3, most preferably less than 0.05 g/cm3. The low density microspheres generally have a diameter less than 200 μm, preferably less than 100 μm, most preferably less than 40 μm.
The microspheres are produced from any appropriate inorganic or organic material, compatible with a use on the skin, that is, nonirritating and nontoxic. These microspheres may be produced thermoplastic materials and can be in the dry or hydrated state. Among hollow microspheres which can be used, special mention may be made of those marketed under the brand name EXPANCEL® (thermoplastic expandable microspheres) by the Akzo Nobel Company, especially those of DE (dry state) or WE (hydrated state) grade. Representative microspheres derived from an inorganic material, include, for instance, “QCEL® Hollow Microspheres” and “EXTENDOSPHERES”™ Ceramic Hollow Spheres”, both available from the PQ Corporation. Examples are: Qcel® 300; Qcel® 6019; Qcel® 6042S.
Additional Ingredients: Either phase of the multi-phase personal cleansing composition, can further comprise a polymeric phase structurant. The compositions of the present invention typically can comprise from about 0.05% to about 10%, preferably from about 0.1% to about 4%, by weight of the phase, of a polymeric phase structurant. Non-limiting examples of polymeric phase structurant include but are not limited to the following examples: naturally derived polymers, synthetic polymers, crosslinked polymers, block copolymers, copolymers, hydrophilic polymers, nonionic polymers, anionic polymers, hydrophobic polymers, hydrophobically modified polymers, associative polymers, and oligomers. Suitable polymeric phase structurants are more fully described in U.S. Pat. No. 5,087,445, to Haffey et al., issued Feb. 11, 1992; U.S. Pat. No. 4,509,949, to Huang et al., issued Apr. 5, 1985, U.S. Pat. No. 2,798,053, to Brown, issued Jul. 2, 1957. See also, CTFA International Cosmetic Ingredient Dictionary, fourth edition, 1991, pp. 12 and 80.
Either phase of the multi-phase personal cleansing compositions can further comprise a liquid crystalline phase inducing structurant, which when present is at concentrations ranging from about 0.3% to about 15%, by weight of the phase, more preferably at from about 0.5% to about 5% by weight of the phase. Suitable liquid crystalline phase inducing structurants include fatty acids (e.g. lauric acid, oleic acid, isostearic acid, linoleic acid) ester derivatives of fatty acids (e.g. propylene glycol isostearate, propylene glycol oleate, glyceryl isostearate) fatty alcohols, trihydroxystearin (available from Rheox, Inc. under the trade name THIXCIN® R). Preferably, the liquid crystalline phase inducing structurant is selected from lauric acid, trihydroxystearin, lauryl pyrrolidone, and tridecanol.
The multi-phase personal cleansing compositions can further comprise an organic cationic deposition polymer in the one or more phases as a deposition aid for the benefit agents described herein. Suitable cationic deposition polymers are more fully described in the co-pending and commonly assigned U.S. patent application No. 60/628,036 filed on Nov. 15, 2003 by Wagner, et al titled “Depositable Solids.”
Other non limiting examples of these optional ingredients include vitamins and derivatives thereof (e.g., ascorbic acid, vitamin E, tocopheryl acetate), sunscreens; thickening agents, preservatives for maintaining the anti microbial integrity of the cleansing compositions, anti-acne medicaments, antioxidants, skin soothing and healing agents (i.e. aloe vera extract, allantoin), chelators, sequestrants and agents suitable for aesthetic purposes (i.e. fragrances, essential oils, skin sensates, lightning agents. pigments, pearlescent agents shiny particles, particles or beads, exfoliating beads, essential oils) and the like. Such optional ingredients are most typically those materials approved for use in cosmetics and that are described in reference books such as the CTFA Cosmetic Ingredient Handbook, Second Edition, The Cosmetic, Toiletries, and Fragrance Association, Inc. 1988, 1992. The preferred pH range of the structured multi-phase personal cleansing composition is from about 5 to about 8.
Method of Use: The mild, multi-phase cleansing compositions of the present invention are preferably applied topically to the desired area of the skin or hair in an amount sufficient to provide effective delivery of the structured surfactant component, hydrophobic benefit material, and particles to the applied surface. The compositions can be applied directly to the skin or indirectly via the use of a cleansing puff, washcloth, sponge or other implement. The compositions are preferably diluted with water prior to, during, or after topical application, and then subsequently the skin or hair rinsed or wiped off, preferably rinsed off of the applied surface using water or a water-insoluble substrate in combination with water.
Method of Manufacture: The multi-phase personal cleansing compositions of the present invention may be prepared by any known or otherwise effective technique, suitable for making and formulating the desired multi-phase product form. It is effective to combine toothpaste-tube filling technology with a spinning stage design. Additionally, the present invention can be prepared by the method and apparatus as disclosed in U.S. Pat. No. 6,213,166 issued to Thibiant, et al. on Apr. 10, 2001. The method and apparatus allows two or more compositions to be filled with a spiral configuration into a single container, requiring at least two nozzles be employed to fill the container. The container is placed on a static mixer and spun as the composition is introduced into the container.
Alternatively, it is effective to combine at least two phases by first placing the separate compositions in separate storage tanks having a pump and a hose attached. The phases are then pumped in predetermined amounts into a single combining section. From the combining section the phases are moved into the blending section and are blended such that the single resulting product exhibits a distinct pattern of the phases. Next, the resultant product is pumped by a single nozzle and filing the container with the resulting product.
If the multi-phase personal cleansing compositions are patterned, it can be desirable to be packaged as a personal cleansing article. The personal cleansing article would comprise these compositions in a transparent or translucent package such that the consumer can view the pattern through the package. Because of the viscosity of the subject compositions it may also be desirable to include instructions to the consumer to store the package upside down, on its cap to facilitate dispensing.
Yield Stress and Zero Shear Viscosity Method: The Yield Stress and Zero Shear Viscosity of a phase of the present composition, can be measured either prior to combining in the composition, or after combining in the composition by separating the phase by suitable physical separation means, such as centrifugation, pipetting, cutting away mechanically, rinsing, filtering, or other separation means.
A controlled stress rheometer such as a TA Instruments AR2000 Rheometer is used to determine the Yield Stress and Zero Shear Viscosity. The determination is performed at 25° C. with the 4 cm diameter parallel plate measuring system and a 1 mm gap. The geometry has a shear stress factor of 79580 m−3 to convert torque obtained to stress.
First a sample of the phase is obtained and placed in position on the rheometer base plate, the measurement geometry (upper plate) moving into position 1 mm above the base plate. Excess phase at the geometry edge is removed by scraping after locking the geometry. If the phase comprises particles discernible to the eye or by feel (beads, e.g.) which are larger than about 150 microns in number average diameter, the gap setting between the base plate and upper plate is increased to the smaller of 4 mm or 8-fold the diameter of the 95th volume percentile particle diameter. If a phase has any particle larger than 5 mm in any dimension, the particles are removed prior to the measurement.
The determination is performed via the programmed application of a continuous shear stress ramp from 0.1 Pa to 1,000 Pa over a time interval of 5 minutes using a logarithmic progression, i.e., measurement points evenly spaced on a logarithmic scale. Thirty (30) measurement points per decade of stress increase are obtained. Stress, strain and viscosity are recorded. If the measurement result is incomplete, for example if material flows from the gap, results obtained are evaluated and incomplete data points excluded. The Yield Stress is determined as follows. Stress (Pa) and strain (unitless) data are transformed by taking their logarithms (base 10). Log(stress) is graphed vs. log(strain) for only the data obtained between a stress of 0.2 Pa and 2.0 Pa, about 30 points. If the viscosity at a stress of 1 Pa is less than 500 Pa-sec but greater than 75 Pa-sec, then log(stress) is graphed vs. log(strain) for only the data between 0.2 Pa and 1.0 Pa, and the following mathematical procedure is followed. If the viscosity at a stress of 1 Pa is less than 75 Pa-sec, the zero shear viscosity is the median of the 4 highest viscosity values (i.e., individual points) obtained in the test, the yield stress is zero, and the following mathematical procedure is not used. The mathematical procedure is as follows. A straight line least squares regression is performed on the results using the logarithmically transformed data in the indicated stress region, an equation being obtained of the form: (1) Log(strain)=m * Log(stress)+b
Using the regression obtained, for each stress value (i.e., individual point) in the determination between 0.1 and 1,000 Pa, a predicted value of log(strain) is obtained using the coefficients m and b obtained, and the actual stress, using Equation (1). From the predicted log(strain), a predicted strain at each stress is obtained by taking the antilog (i.e., 10x for each x). The predicted strain is compared to the actual strain at each measurement point to obtain a % variation at each point, using Equation (2).
The Yield Stress is the first stress (Pa) at which % variation exceeds 10% and subsequent (higher) stresses result in even greater variation than 10% due to the onset of flow or deformation of the structure. The Zero Shear Viscosity is obtained by taking a first median value of viscosity in Pascal-seconds (Pa-sec) for viscosity data obtained between and including 0.1 Pa and the Yield Stress. After taking the first median viscosity, all viscosity values greater than 5-fold the first median value and less than 0.2× the median value are excluded, and a second median viscosity value is obtained of the same viscosity data, excluding the indicated data points. The second median viscosity so obtained is the Zero Shear Viscosity.
Ultracentrifugation Method: The Ultracentrifugation Method is used to determine the percent of a structured domain or an opaque structured domain that is present in a structured multi-phase personal cleansing composition that comprises a first visually distinct phase comprising a structured surfactant component. The method involves the separation of the composition by ultracentrifugation into separate but distinguishable layers. The structured multi-phase personal cleansing composition of the present invention can have multiple distinguishable layers, for example a non-structured surfactant layer, a structured surfactant layer, and a benefit layer.
First, dispense about 4 grams of multi-phase personal cleansing composition into Beckman Centrifuge Tube (11×60 mm). Next, place the centrifuge tubes in an Ultracentrifuge (Beckman Model L8-M or equivalent) and ultracentrifuge using the following conditions: 50,000rpm, 18 hours, and 25° C.
After ultracentrifuging for 18 hours, determine the relative phase volume by measuring the height of each layer visually using an Electronic Digital Caliper (within 0.01 mm). First, the total height is measured as Ha which includes all materials in the ultracentrifuge tube. Second, the height of the benefit layer is measured as Hb. Third, the structured surfactant layer is measured as Hc. The benefit layer is determined by its low moisture content (less than 10% water as measured by Karl Fischer Titration). It generally presents at the top of the centrifuge tube. The total surfactant layer height (Hs) can be calculated by this equation: Hs=Ha−Hb
The structured surfactant layer components may comprise several layers or a single layer. Upon ultracentrifugation, there is generally an isotropic layer at the bottom or next to the bottom of the ultracentrifuge tube. This clear isotropic layer typically represents the non-structured micellar surfactant layer. The layers above the isotropic phase generally comprise higher surfactant concentration with higher ordered structures (such as liquid crystals). These structured layers are sometimes opaque to naked eyes, or translucent, or clear. There is generally a distinct phase boundary between the structured layer and the non-structured isotropic layer. The physical nature of the structured surfactant layers can be determined through microscopy under polarized light. The structured surfactant layers typically exhibit distinctive texture under polarized light. Another method for characterizing the structured surfactant layer is to use X-ray diffraction technique. Structured surfactant layer display multiple lines that are often associated primarily with the long spacings of the liquid crystal structure. There may be several structured layers present, so that Hc is the sum of the individual structured layers. If a coacervate phase or any type of polymer-surfactant phase is present, it is considered a structured phase.
Finally, the structured domain volume ratio is calculated as follows: Structured Domain Volume Ratio=Hc/Hs *100%. If there is no benefit phase present, use the total height as the surfactant layer height, Hs=Ha.
Lather Volume Test: Lather volume of a cleansing phase, a structured surfactant component or a structured domain of a structured multi-phase personal cleansing composition, is measured using a graduated cylinder and a rotating apparatus. A 1,000 ml graduated cylinder is used which is marked in 10 ml increments and has a height of 14.5 inches at the 1,000 ml mark from the inside of its base (for example, Pyrex No. 2982). Distilled water (100 grams at 25° C.) is added to the graduated cylinder. The cylinder is clamped in a rotating device, which clamps the cylinder with an axis of rotation that transects the center of the graduated cylinder. Inject 0.50 grams of a structured surfactant component or cleansing phase from a syringe (weigh to ensure proper dosing) into the graduated cylinder onto the side of the cylinder, above the water line, and cap the cylinder. When the sample is evaluated, use only 0.25 cc, keeping everything else the same. The cylinder is rotated for 20 complete revolutions at a rate of about 10 revolutions per 18 seconds, and stopped in a vertical position to complete the first rotation sequence. A timer is set to allow 15 seconds for lather generated to drain. After 15 seconds of such drainage, the first lather volume is measured to the nearest 10 ml mark by recording the lather height in ml up from the base (including any water that has drained to the bottom on top of which the lather is floating).
If the top surface of the lather is uneven, the lowest height at which it is possible to see halfway across the graduated cylinder is the first lather volume (ml). If the lather is so coarse that a single or only a few foam cells which comprise the lather (“bubbles”) reach across the entire cylinder, the height at which at least 10 foam cells are required to fill the space is the first lather volume, also in ml up from the base. Foam cells larger than one inch in any dimension, no matter where they occur, is designated as unfilled air instead of lather. Foam that collects on the top of the graduated cylinder but does not drain is also incorporated in the measurement if the foam on the top is in its own continuous layer, by adding the ml of foam collected there using a ruler to measure thickness of the layer, to the ml of foam measured up from the base. The maximum lather height is 1,000 ml (even if the total lather height exceeds the 1,000 ml mark on the graduated cylinder). 30 seconds after the first rotation is completed, a second rotation sequence is commenced which is identical in speed and duration to the first rotation sequence. The second lather volume is recorded in the same manner as the first, after the same 15 seconds of drainage time. A third sequence is completed and the third lather volume is measured in the same manner, with the same pause between each for drainage and taking the measurement.
The lather results after each sequence are added together and the Total Lather Volume determined as the sum of the three measurements, in milliters (“ml”). The Flash Lather Volume is the result after the first rotation sequence only, in ml, i.e., the first lather volume. Compositions according to the present invention perform significantly better in this test than similar compositions in conventional emulsion form.
T-Bar Method for Assessing Structured Surfactant Stability In Presence of Lipid: The stability of a surfactant-containing phase (“cleansing phase” or “first visually distinct phase”) in the presence of lipid can be assessed using a T-Bar Viscosity Method. The apparatus for T-Bar measurement includes a Brookfield DV−II+Pro Viscometer with Helipath Accessory; chuck, weight and closer assembly for T-bar attachment; a T-bar Spindle D, a personal computer with Rheocalc software from Brookfield, and a cable connecting the Brookfield Viscometer to the computer. First, weigh 40 grams of the cleansing phase in a 4-oz glass jar. Centrifuge the jar at 2,000 rpm for 20 min to de-aerate the cleansing phase, which may also remove large particles by sedimentation or flotation. Measure the height of the cleansing phase “Hsurf” using an Electronic Caliper with a precision of 0.01 mm. Measure the initial T-bar viscosity by carefully dropping the T-Bar Spindle to the interior bottom of the jar and set the Helipath stand to travel in an upward direction. Open the Rheocalc software and set the following data acquisition parameters: set Speed to 5 rpm, set Time Wait for Torque to 00:01 (1 second), set Loop Start Count at 40. Start data acquisition and turn on the Helipath stand to travel upward at a speed of 22 mm/min. The initial T-Bar viscosity “Tini,” is the average T-Bar viscosity reading between the 6th reading and the 35th reading (the first five and the last five readings are not used for the average T-Bar viscosity calculation). Cap the jar and store at ambient temperature. Prepare a separate lipid blend by heating a vessel to 180° F. (82.2° C.) and add together 70 parts of Petrolatum (G2218 from WITCO) and 30 parts of Hydrobrite 1000 White Mineral Oil. Cool the vessel to 110° F. (43.3° C.)with slow agitation (200 rpm). Stop agitation and cool the vessel to ambient temperature overnight. Add 40 grams of the lipid blend (70/30 Pet/MO) to the jar containing the first visually distinct phase. Stir the first visually distinct phase and lipid together using a spatula for 5 min. Place the jar at 113° F. (45° C.) for 5 days. After 5 days, centrifuge the jar at 2000 rpm for 20 min (do not cool the jar first).
After centrifugation, cool down the jar and contents to ambient conditions, overnight. Observe the contents of the jar. A stable cleansing phase exhibits a uniform layer at the bottom of the jar, below the less dense petrolatum/oil phase. An unstable cleansing phase can form layers not present in the originally centrifuged cleansing phase (i.e., an isotropic phase) either at the bottom or between the cleansing phase-lipid interface. If more than one layer is present in the cleansing phase, measure the height of each newly formed layer, “Hnew” using an Electronic Caliper. Add together the heights of all the newly formed layers. The new phase volume ratio is calculated as Hnew/Hsurf *100% ,using the height of all new layers added together as Hnew. Preferably, a stable structured cleansing phase forms less than 10% of new phase volume. More preferably, a stable structured cleansing phase forms less than 5% of new phase volume. Most preferably, a stable structured cleansing phase forms 0% of new phase volume.
The T-Bar viscosity of the centrifuged contents of the jar is then measured using the T-Bar method above. Open the Rheocalc software and set the following data acquisition parameters: set Speed to 5 rpm, set Time Wait for Torque to 00:01 (1 second), set Loop Start Count at 80. Start the data acquisition and turn on the Helipath stand to travel upward at a speed of 22 mm/min. There is usually a distinctive viscosity jump between the first visually distinct phase layer and the lipid layer. The average cleansing phase T-Bar viscosity after lipid exposure, “Taft” is the average reading between the 6th T-Bar viscosity and the last T-Bar viscosity reading before the jump in viscosity due to the lipid layer. In the case where there is no distinctive T-Bar viscosity jump between cleansing phase and lipid phase, only use the average reading between the 6th T-Bar viscosity reading and the 15th reading as the average cleansing phase T-bar viscosity, Taft. Preferably, a stable structured cleansing phase has Taft higher than 10,000 cP. More preferably, a stable structured cleansing phase has Taft higher than 15,000 cP. Most preferably, a stable structured first visually distinct phase has Taft higher than 20,000 cP
Viscosity Retention is calculated as Taft/Tini*100%. Preferably, a stable structured cleansing phase has >50% Viscosity Retention. More preferably, a stable structured cleansing phase has >70% Viscosity Retention. Most preferably, a stable structured cleansing phase has >80% Viscosity Retention.
The following first visually distinct phases are prepared as non-limiting examples (chemical content is shown). Examples 1 and 2 are Comparative Examples of the first visually distinct phase of the present invention. Examples 3-5 are examples of the first visually distinct phase of the present invention.
Examples 1 and 2 are comparative examples of the first visually distinct phase of the present invention which comprise all linear anionic surfactants. Examples 3-5 are examples of the present invention comprising a mix of linear and branched anionic surfactants. Of the mixed anionic surfactant compositions Examples 3-5, compositions with lower sodium trideceth sulfate exhibited higher flash and total lather volumes. However, mixtures of branched and linear anionic surfactant (Examples 3-5) exhibited higher flash and total lather volume than all linear anionic compositions (Comparative Examples 1 and 2), and improved stability.
The Examples 6-9 in Table 2 can be prepared by dispersing polymers in water with high shear, adding salt and remaining ingredients except petrolatum and mineral oil, heating to 50° C., adding the petrolatum and mineral oil as a liquid at 80° C., and agitating until homogeneous without high shear. Pigments having no water soluble components are preferably used. A particle size of about 5-100 microns for the petrolatum component is obtained for most of the particles.
The Examples 10-15 in Table 3 can be prepared by melting petrolatum at 80° C. and adding mineral oil, pigment, P135 and Span 80 into a vessel. In a separate vessel heat water to 75° C. and add salt and EDTA. Add water phase slowly to oil phase with paddle mixing and bring temperature down to 45° C. continuing to mix. Add preservative and perfume and continue to mix.
The Examples 21-22 in Table 4 can be prepared by melting petrolatum at 80° C. and add mineral oil and pigment reduce temperature to 60° C. in a vessel. In a separate vessel, mix water, one surfactant system, salt and EDTA at room temperature. Add water phase slowly to oil phase with paddle mixing and bring temperature down to 45° C. continuing to mix. Add preservative and perfume and continue to mix.
It should be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification includes every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification includes every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein. All parts, ratios, and percentages herein, in the Specification, Examples, and Claims, are by weight and all numerical limits are used with the normal degree of accuracy afforded by the art, unless otherwise specified.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.