BACON JULIE LAURE-ANNE (GB)
BAINES FIONA LOUISE (GB)
COOK JOANNE LOUISE (GB)
KEELING ANNIE JAYE (GB)
SHAW NEIL SCOTT (GB)
UNILEVER NV (NL)
CONOPCO INC DBA UNILEVER (US)
| US20120251476A1 | 2012-10-04 | |||
| US20120171146A1 | 2012-07-05 | |||
| US20140112879A1 | 2014-04-24 | |||
| EP1925290A1 | 2008-05-28 |
| CLAIMS 1. A personal cleansing composition comprising, in an aqueous continuous phase: (i) an alkyl ether sulfate anionic surfactant of general formula (I): R-0-(CH2CH O)n-S03-M+ (I) in which R is selected from linear or branched alkyl groups having from 10 to 14 carbon atoms and mixtures thereof; n is a number that represents the degree of ethoxylation and ranges from 2 to 4; and M is an solubilizing cation; (ii) an N-acyl glutamate anionic surfactant of general formula (II): COO" M+ O .CH2 -CH X. HOOC ^CH2 ΝΉ or COOH .CH, ,CH . M "OOC 'ΝΗ ' in which RC(O) is selected from linear or branched, saturated or unsaturated acyl groups having from 8 to 22 carbon atoms and mixtures thereof; and M is a solubilizing cation, and (iii) an amido betaine amphoteric surfactant of general formula (III): O R2 R1— C— NH(CH2)m— N— CH2C02 ',3 (III) where m is 2 or 3; R1C(0) is selected from linear or branched, saturated or unsaturated acyl groups having from 8 to 22 carbon atoms and mixtures thereof; and R2 and R3are each independently selected from alkyl, hydroxyalkyl or carboxyalkyl groups having from 1 to 6 carbon atoms and mixtures thereof; in which the level of (i) ranges from 3 to 10% by weight based on the total weight of the composition; in which the level of (ii) ranges from 0.1 to 5% by weight based on the total weight of the composition; in which the level of (iii) ranges from 0.1 to 5% by weight based on the total weight of the composition; and in which the combined level of (ii) and (iii) does not exceed 6% by weight based on the total weight of the composition. 2. A composition according to claim 1 , in which the alkyl ether sulfate anionic surfactant of general formula (I) is SLES 3EO, in an amount ranging from 5 to 7% by weight based on the total weight of the composition. 3. A composition according to claim 1 or claim 2, in which the N-acyl glutamate anionic surfactant of general formula (II) is selected from sodium cocoyi glutamate, disodium cocoyi glutamate and mixtures thereof, in an amount ranging from 1 to 3.5% by weight based on the total weight of the composition. 4. A composition according to any preceding claim, in which the amido betaine amphoteric surfactant of general formula (III) is cocamidopropylbetaine, in an amount ranging from 1 to 3% by weight based on the total weight of the composition. 5. A composition according to any preceding claim, which contains 0%, or less than 0.01 % (by weight based on the total weight of the composition), of simple betaine amphoteric surfactants having the general formula (IV): where R1 is selected from linear alkyl groups having from 10 to 22 carbon atoms and mixtures thereof; and R2 and R3are each independently selected from alkyl, hydroxyalkyi or carboxyalkyl groups having from 1 to 6 carbon atoms and mixtures thereof. 6. A method of cleansing and conditioning hair, comprising the following sequential steps: (i) topically applying a composition according to any one of claims 1 to 5 to the hair; (ii) massaging the composition into the hair and scalp; (iii) rinsing the composition off the hair and scalp with water, and (iv) drying the hair. |
Field of the Invention The present invention relates to personal cleansing compositions such as liquid soaps, body washes and shampoos.
Background and Prior Art Personal cleansing compositions such as liquid soaps, body washes and shampoos are invariably based on surfactants. Anionic surfactants such as sodium lauryl ether sulfate exhibit superior cleansing and foaming properties, and the established combination of sodium lauryl ether sulfate with cocamidopropylbetaine is still the most commonly used in such compositions. Some consumers, particularly those with dry and/or damaged hair, desire milder compositions. One approach for providing mildness is to replace some of the sodium lauryl ether sulfate with co- surfactants.
Acyl glutamates have been identified as a class of co-surfactant which are particularly suitable for the production of shampoos for dry and/or damaged hair because of their mild, gentle cleansing action and affinity for keratin. Acyl glutamates have also been claimed to improve the
dermatological characteristics of surfactant formulations containing sodium lauryl ether sulfate.
Although acyl glutamates are desirable co-surfactants in personal cleansing compositions for the reasons described above, they can be difficult to solubilize under some circumstances, leading to stringy or lumpy compositions. This is especially the case at low temperatures (e.g. 15°C or below). This represents a problem forthe formulator, since such compositions are potentially unusable in countries where low temperatures prevail for all or part of the year. The present invention addresses this problem.
Summary of the Invention
The present invention provides a personal cleansing composition comprising, in an aqueous continuous phase: (i) an alkyl ether sulfate anionic surfactant of general formula (I):
R-0-(CH 2 CH O)n-S0 3 -M + (I) in which R is selected from linear or branched alkyl groups having from 10 to 14 carbon atoms and mixtures thereof; n is a number that represents the degree of ethoxylation and ranges from 2 to 4; and M is an solubilizing cation;
(ii) an N-acyl glutamate anionic surfactant of general formula (II):
COO " M
O
HOOC CH 2 NH
or
COOH
, CH 2 CH C ^
M + " OOC ^CH 2 NH R ^ in which RC(O) is selected from linear or branched, saturated or unsaturated acyl groups having from 8 to 22 carbon atoms and mixtures thereof; and M is a solubilizing cation, and iii) an amido betaine amphoteric surfactant of general formula (III):
(III) where m is 2 or 3; R 1 C(0) is selected from linear or branched, saturated or unsaturated acyl groups having from 8 to 22 carbon atoms and mixtures thereof; and R 2 and R 3 are each independently selected from alkyl, hydroxyalkyl or carboxyalkyl groups having from 1 to 6 carbon atoms and mixtures thereof; in which the level of (i) ranges from 3 to 10% by weight based on the total weight of the composition; in which the level of (ii) ranges from 0.1 to 5% by weight based on the total weight of the composition; in which the level of (iii) ranges from 0.1 to 5% by weight based on the total weight of the composition; and in which the combined level of (ii) and (iii) does not exceed 6% by weight based on the total weight of the composition.
Detailed Description of the Invention
All molecular weights as used herein are weight average molecular weights, unless otherwise specified.
By "aqueous continuous phase" is meant a continuous phase which has water as its basis.
Suitably, the composition of the invention will comprise from about 50 to about 90%, preferably from about 55 to about 85%, more preferably from about 60 to about 85%, most preferably from about 65 to about 83% water (by weight based on the total weight of the composition).
The composition of the invention comprises one or more alkyl ether sulfate anionic surfactants of general formula (I) defined above.
Preferably R in general formula (I) is a Cioor C12 linear alkyl group.
Preferably n in general formula (I) ranges from 3.0 to 3.5, more preferably from 3.0 to 3.2.
Preferably M in general formula (I) is selected from alkali metal cations (such as sodium or potassium), ammonium cations and substituted ammonium cations (such as alkylammonium, alkanolammonium or glucammonium).
Particularly preferred is SLES 3EO (i.e. sodium lauryl ether sulfate in which the average degree of ethoxylation n is 3.0) Commercially produced alkyl ether sulfate anionic surfactants generally contain a mixture of homologues and the degree of ethoxylation is a statistical average value which may be an integer or a fraction. The value of n in general formula (I) is governed by the starting molar ratio of ethylene oxide to aliphatic alcohol in the ethoxylation reaction and the temperature, time and catalytic conditions under which the ethoxylation reaction takes place.
A commercially produced alkyl ether sulfate anionic surfactant having general formula (I) will usually comprise a mixture of homologues in which from 55 to 80 mol% of the total mixture is made up of homologues with ethoxy chains of 5EO or less (down to 0EO, i.e. unethoxylated alkyl sulfate), with the remainder of the mixture made up of homologues with ethoxy chains of 6EO or more (up to about 10EO). Higher homologues (e.g. up to about 15EO) may also be present on small amounts (typically no more than 1 to 2 mol% of the total mixture per individual homologue). A typical breakdown in molar percentage terms for commercially produced alkyl ether sulfate anionic surfactants having general formula (I) is given in the following Table:
X % m/m of R-0-(CH 2 CH 2 -0)x-S03-M+
0 10 to 15
1 7 to 1 1
2 10 to 12
3 10 to 15
4 10 to 12
5 9 to 1 1
6 6 to 10
7 5 to 9
8 3 to 7
9 3 to 5
10 2 to 4
11 U t0
12 0 to 2
13 O to 1
14 O to 1
15 0 to 0.5 Examples of commercially produced alkyl ether sulfate anionic surfactants having general formula (I) for use in the invention include STEOL® CS-330 HA (ex Stepan Company) and Texapon® N 70 LS (ex BASF). Mixtures of any of the above described materials may also be used.
Preferably the level of alkyl ether sulfate anionic surfactant of general formula (I) ranges from 5 to 7% by weight based on the total weight of the composition.
In a preferred composition according to the invention the alkyl ether sulfate anionic surfactant of general formula (I) is SLES 3EO (i.e. sodium lauryl ether sulfate in which the average degree of ethoxylation n is 3.0), in an amount ranging from 5 to 7% by weight based on the total weight of the composition.
The composition of the invention comprises one or more N-acyl glutamate anionic surfactants of general formula (II) defined above.
Preferably, RC(O) in general formula (II) is selected from linear acyl groups having from Cs to C-is carbon atoms and 0, 1 , 2 or 3 double bonds and mixtures thereof. Preferably M in general formula (II) is selected from alkali metal cations (such as sodium or potassium), ammonium cations and substituted ammonium cations (such as alkylammonium, alkanolammonium or glucammonium).
More preferably, RC(O) in general formula (II) is selected from lauroyi, myristoyi, palmitoyi, stearoyi, oleoyl and cocoyl groups and mixtures thereof.
Most preferably RC(O) in general formula (II) is a cocoyl group. "Cocoyl" is a mixture of acyl groups derived from coconut oil and having a distribution of carbon chain lengths corresponding to that found in coconut fatty acids. Generally in such a mixture at least about 85% (by weight based on total weight) of the RC(O) carbon chains are Cs to Cis; and at least about 50% (by weight based on total weight) of the RC(O) carbon chains are Cs to C12. a typical cocoyi group, the RC(O) carbon chain length distribution is generally defined as follows: c 8 5 to 10 wt.%
Examples of commercially produced acyl glutamate anionic surfactants of general formula (II) for use in the invention include sodium cocoyi glutamate (AMISOFT® CS-11 ex Ajinomoto Co., Inc.), disodium cocoyi glutamate (AMISOFT® ECS-22SB ex Ajinomoto Co., Inc.), triethanolammonium cocoyi glutamate (AMISOFT® CT-12 ex Ajinomoto Co., Inc.) triethanolammonium lauroyi glutamate (AMISOFT® LT-12 ex Ajinomoto Co.Jnc.), sodium myristoyl glutamate (AMISOFT® MS-11 ex Ajinomoto Co.Jnc.) ,sodium stearoyl glutamate (AMISOFT® HS-11 P ex Ajinomoto Co.Jnc.) and mixtures thereof.
Preferred N-acyl glutamate anionic surfactants of general formula (II) for use in the invention include sodium cocoyi glutamate, disodium cocoyi glutamate and mixtures thereof
Mixtures of any of the above described materials may also be used.
Preferably the level of N-acyl glutamate anionic surfactants of general formula (II) ranges from 0.5 to 4%, more preferably from 1 to 3.5% by weight based on the total weight of the composition.
In a preferred composition according to the invention the N-acyl glutamate anionic surfactant of general formula (II) is selected from sodium cocoyi glutamate, disodium cocoyi glutamate and mixtures thereof, in an amount ranging from 1 to 3.5% by weight based on the total weight of the composition.
The composition of the invention comprises one or more amido betaine amphoteric surfactants of general formula (III) defined above. Amido betaines have a zwitterionic structure which makes them amphoteric. Preferably, R 1 C(0) in general formula (III) is selected from linear acyl groups having from Cs to Cie carbon atoms and 0, 1 , 2 or 3 double bonds and mixtures thereof.
More preferably, R 1 C(0) in general formula (III) is selected from lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl and cocoyl groups and mixtures thereof.
Most preferably R 1 C(0) in general formula (III) is a cocoyl group...
Preferably R 2 and R 3 in general formula (III) are both methyl.
Mixtures of any of the above described materials may also be used.
The level of amido betaine amphoteric surfactants of general formula (III) preferably ranges from 1 to 3.5%, more preferably from 1 to 3% by weight based on the total weight of the composition.
In a preferred composition according to the invention the amido betaine amphoteric surfactant of general formula (III) is cocamidopropylbetaine, in an amount ranging from 1 to 3% by weight based on the total weight of the composition. The inventors have found that simple betaine amphoteric surfactants do not provide satisfactory performance in the context of this invention. Accordingly, it is preferred that such materials are absent from the composition of the invention, or included in minor quantities only, such less than 0.1%, and more preferably less than 0.01 % by weight based on the total weight of the composition. The term "simple betaine amphoteric surfactant" in the context of this invention denotes materials having the general formula (IV):
where R 1 is selected from linear alkyl groups having from 10 to 22 carbon atoms and mixtures thereof; and R 2 and R 3 are each independently selected from alkyl, hydroxyalkyl or carboxyalkyl groups having from 1 to 6 carbon atoms and mixtures thereof. An example of such a material is coco-betaine (where R 1 represents the alkyl groups derived from coconut oil and R 2 and R 3 are both methyl).
The composition of the invention preferably comprises one or more dispersed benefit agents selected from hydrophobic emulsion droplets and particulate solids.
The term "benefit agent" in the context of this invention includes materials which can provide a benefit to the hair and/or the scalp and/or the skin (preferably the hair and/or the scalp) as well as those materials which are beneficially incorporated into personal cleansing compositions, such as aesthetic agents.
Hydrophobic emulsion droplets for inclusion in the composition of the invention typically have a mean droplet diameter (D3,2) of 4 micrometres or less. Preferably the mean droplet diameter (D3,2) is 1 micrometre or less, more preferably 0.5 micrometre or less, and most preferably 0.25 micrometre or less.
A suitable method for measuring the mean droplet diameter (D3,2) is by laser light scattering using an instrument such as a Malvern Mastersizer. Preferred hydrophobic emulsion droplets in this context include emulsion droplets of hair and/or skin conditioning ingredients such as silicones and hydrocarbon oils.
Suitable silicones for use in the invention include polydiorganosiloxanes, in particular
polydimethylsiloxanes (dimethicones), polydimethyl siloxanes having hydroxyl end groups (dimethiconols), and amino-functional polydimethylsiloxanes (amodimethicones).
Such silicones are preferably non-volatile (with vapour pressure of less than 1000 Pa at 25°C), and preferably have a molecular weight of greater than 100,000, more preferably greater than 250,000.
Such silicones preferably have a kinematic viscosity of greater than 50,000 cS (mm 2 . s "1 ) and more preferably a kinematic viscosity of greater than 500,000 cS (mm 2 .s "1 ). Silicone kinematic viscosities in the context of this invention are measured at 25°C and can be measured by means of a glass capillary viscometer as set out further in Dow Corning Corporate Test Method CTM004 July 20, Suitable silicones for use in the invention are available as pre-formed silicone emulsions from suppliers such as Dow Coming and GE Silicones. The use of such pre-formed silicone emulsions is preferred for ease of processing and control of silicone particle size. Such pre-formed silicone emulsions will typically additionally comprise a suitable emulsifier, and may be prepared by a chemical emulsification process such as emulsion polymerisation, or by mechanical emulsification using a high shear mixer. Pre-formed silicone emulsions having a mean droplet diameter (D3,2) of less than 0.15 micrometres are generally termed microemulsions.
Examples of suitable pre-formed silicone emulsions include emulsions DC2-1766, DC2-1784, DC- 1785, DC-1786, DC-1788, DC-1310, DC-7123 and microemulsions DC2-1865 and DC2-1870, all available from Dow Corning. These are all emulsions/microemulsions of dimethiconol. Also suitable are amodimethicone emulsions such as DC939 (from Dow Coming) and SME253 (from GE Silicones). Mixtures of any of the above described silicone emulsions may also be used.
Suitable hydrocarbon oils for use in the invention include saturated, non-polar straight or branched- chain aliphatic or alicyclic hydrocarbons having from about 10 to about 50 carbon atoms, and mixtures thereof.
Such hydrocarbon oils preferably have a kinematic viscosity of 1 to 35 cS (mm 2 .s "1 ) at 40°C and a specific gravity of 0.76 to 0.87 at 25°C.
A preferred hydrocarbon oil in the context of the present invention is light mineral oil. Mineral oils are clear oily liquids obtained from petroleum oil, from which waxes have been removed, and the more volatile fractions removed by distillation. The fraction distilling between 250°C to 300°C is termed mineral oil, and it consists of a mixture of hydrocarbons, in which the number of carbon atoms per hydrocarbon molecule generally ranges from Cio to C40. The mineral oil may be characterised in terms of its viscosity, where light mineral oil is less viscous than heavy mineral oil. A suitable light mineral oil will generally have a kinematic viscosity of 3.9 to 5.0 cS (mm 2 .s "1 ) at 40°C and a specific gravity of 0.810 to 0.830 at 25°C. Such materials are commercially available under the brand name Lytol®. Suitable particulate solids for inclusion in the composition of the invention include solid antimicrobial actives (such as zinc pyridinethione, climbazole, sulphur, piroctone olamine, octopirox, selenium disulphide and ketoconazole), solid colorants (such as hair dyes and pigments), and flaky or platelet pearlescers or opacifiers (such as magnesium aluminium silicate, zinc oxide, titanium dioxide and coated mica).
Mixtures of any of the above described materials may also be used.
In a typical composition according to the invention the level of dispersed benefit agent (as defined above) depends on the particular material(s) used, but generally ranges from 0.01 to 20%, preferably from 0.02 to 10% by weight based on the total weight of the composition. In preferred compositions according to the invention, the one or more dispersed benefit agents includes one or more silicone emulsions (as further described above) and the level of silicone (perse as active ingredient) ranges from 0.01 to 10%, preferably from 0.5 to 5% by weight based on the total weight of the composition..
The composition of the invention preferably includes one or more cationic polymers. Such polymers may enhance the delivery of conditioning agents and thereby improve the conditioning benefits obtained.
Cationic polymers typically contain cationic nitrogen-containing groups such as quaternary ammonium or protonated amino groups. The cationic protonated amines can be primary, secondary, or tertiary amines (preferably secondary or tertiary). The average molecular weight of the cationic polymer is preferably from 5,000 to 10 million. The cationic polymer preferably has a cationic charge density of from 0.2 meq/gm to 7 meq/gm.
The term "cationic charge density" in the context of this invention refers to the ratio of the number of positive charges on a monomelic unit of which a polymer is comprised to the molecular weight of the monomelic unit. The charge density multiplied by the polymer molecular weight determines the number of positively charged sites on a given polymer chain.
The cationic nitrogen-containing moiety of the cationic polymer is generally present as a substituent on all, or more typically on some, of the repeat units thereof. The cationic polymer may be a homo- polymer or co-polymer of quaternary ammonium or cationic amine-substituted repeat units, optionally in combination with non-cationic repeat units. Particularly suitable cationic polymers for use in the invention include polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives.
A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic guar gum derivative, such as guar hydroxypropyltrimethylammonium chloride,
(commercially available from Rhodia® in their JAGUAR® trademark series). Examples of such materials are JAGUAR ® C13S, JAGUAR ® C14, JAGUAR® C15 and JAGUAR ® C17. Mixtures of any of the above described cationic polymers may also be used.
When included, the total level of cationic polymer in the composition is preferably from 0.05% to 2% and more preferably from 0.1 to 0.5% by weight based on the total weight of the composition. The composition of the invention preferably includes one or more structurants to assist in the suspension of dispersed benefit agent and provide phase stability. Suitable structurants include polyacrylic acids, cross-linked polymers of acrylic acid, copolymers of acrylic acid with a hydrophobic monomer, copolymers of carboxylic acid-containing monomers and acrylic esters, cross-linked copolymers of acrylic acid and acrylate esters, heteropolysaccharide gums and crystalline long chain acyl derivatives.
Mixtures of any of the above structurants may be used.
When included, the total level of structurant is generally 0.1 to 10%, preferably from 0.5 to 6%, more preferably from 0.9 to 4% by weight based on the total weight of the composition.
The composition of the invention may suitably include at least one inorganic electrolyte. The inorganic electrolyte may be used to help provide viscosity to the composition. The viscosity of the composition suitably ranges from 6,000 to 10,000 mPa.s, preferably from 7,000 to 9,000 mPa.s, more preferably from 7,500 to 8,500 mPa.s when measured using a Brookfield V2 viscometer (spindle RTV5, 1 minute, 20rpm) at 30°C. Suitable inorganic electrolytes include metal chlorides (such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, zinc chloride, ferric chloride and aluminium chloride) and metal sulfates (such as sodium sulfate and magnesium sulfate). Examples of preferred inorganic electrolytes for use in the invention include sodium chloride, potassium chloride, magnesium sulfate and mixtures thereof.
Mixtures of any of the above described materials may also be suitable. The level of inorganic electrolyte in compositions of the invention generally ranges from about 1 to about 25%, preferably from about 2 to about 20%, more preferably from about 3 to about 15% (by total weight inorganic electrolyte based on the total weight of the composition).
A composition of the invention may contain further optional ingredients to enhance performance and/or consumer acceptability. Examples of such ingredients include
fragrance, dyes and pigments, pH adjusting agents and preservatives or antimicrobials. Each of these ingredients will be present in an amount effective to accomplish its purpose. Generally these optional ingredients are included individually at a level of up to 5% by weight based on the total weight of the composition.
A mildly acidic pH is often desirable in shampoos for reasons such as reduced hair fibre swelling, improved hair lustre, better compatibility with acidic skin or hair care actives in the formulation and optimized efficacy of certain organic preservative systems. The pH of the composition of the invention preferably ranges from 3 to 6, more preferably from 4 to 5.5 and most preferably from 4.5 to 5.1.
The composition of the invention is primarily intended for topical application to the body, preferably the hair and scalp. Most preferably the composition of the invention is topically applied to the hair and then massaged into the hair and scalp. The composition is then rinsed off the hair and scalp with water prior to drying the hair.
The invention will be further illustrated by the following, non-limiting Examples, in which all percentages quoted are by weight based on total weight unless otherwise stated. EXAMPLES
A range of shampoo formulations were prepared, with varying amounts of sodium lauryl ether sulphate (SLES), sodium cocoyl glutamate (SCG) and cocamidopropylbetaine (CAPB) respectively.
An extensional rheometer (HAAKE™ CaBER™ 1 Capillary Breakup Extensional Rheometer) was used to quantify the extensional properties of the formulations using normal force measurement. After placing a sample between two plates, the upper plate moves upwards at very high speed and produces a fluid filament. A laser micrometer is used to determine the decrease in filament diameter as a function of time.
The results are shown in Table 1 below. Examples 1 to 3 represent formulations according to the invention. Examples A to C represent comparative examples (not according to the invention).
Table 1
The results show that Examples A, B and C (comparative examples) are unacceptably lumpy or stringy in texture due to the persistence of fluid filaments in these formulations, as shown by their extended filament decay times.
By contrast, Examples 1 to 3 (according to the invention) provide consumer-acceptable rheology since fluid filaments do not persist for any significant length of time in these formulations.
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