HAIR CLEANSING COMPOSITIONS
The present invention is concerned with shampoo and personal washing compositions which give improved feel to the hair during and after washing. In particular, it is concerned with improvements to opacified aqueous compositions which contain anionic and/or amphoteric cleansing surfactants and waxy opacifier material.
Human hair becomes soiled from oils secreted by the body a-nd from the surrounding environment, leading to an unpleasant , greasy feel to the hair. This has led to the habit of frequent hair-washing to maintain the cleanliness of the hair.
Different consumers with differing hair types have varying requirements from a shampoo in addition to simply cleansing the hair. A basic shampoo composition, containing only cleansing surfactant and water, would clean the hair, but would leave long hair in a tangled state and difficult to comb. On drying the hair would be likely to be lacking in shine (due to degreasing) and prone to feeling dry, and also prone to build up of static electricity during brushing.
Consequently, various attempts have been made to overcome the technical problems arising from simple cleansing shampoos. One approach is to apply a separate conditioning formulation to the hair after shampooing, while the hair is still wet.
Another approach, which simplifies the hair maintenance routine, i s to incorporate hair conditioning benefit agents into the shampoo itself , so that only one compo sition needs to be appl ied to the hair rather than two compo sitions .
There is a proliferation of patents and patent applications concerned with such compositions , hereinafter described as conditioning shampoos . One typical conditioning ingredient used in conditioning shampoos is hair conditioning oil , such as triglyceride , hydrocarbon or silicone oil, p resent as discrete droplets or particles suspended in the shampoo composition . In order to achieve stability of "the suspended particles to phase separation, suspending agent s are used such as vi scosity-modifying polymers .
Alternatively, materials which form a solid gel—like network may be used to stabilise the suspension. EP-A-0181 773 discloses conditioning shampoos with dispersed non-volatile silicone droplets stabilised by long chain (Ci6 to C22) acyl derivatives, such as ethylene glycol distearate^ present in the form of crystals.
Long-chain waxy crystals are also used as pearlescers or pearlising waxes in shampoos to provide an aesthetic appeal to the consumer. They may be added and processed as described in EP-A-0181 773 to provide a structuring benefit, or they may be added as a pre-formed concentrate (as described in the article by Norbert Boyxen in Olaj, Szappan, Koz etika 50 (3) 2001 pages 100 to 104) .
This article also describes opacifiers (La esoft TM Benz) which give a milk-like appearance to the shampoo . This appearance is preferred by some consumers over the more traditional pearlised shampoo. These waxy opacifiers provide the advantage of improved biodegradabili ty over prior art polyacrylate dispersions which were previously used to provide a milky appearance. When such ingredients are used as pearlescers, the preferred crystal shape is plate-like. When used to give a milky appearance, the preferred shape is near-spherical.
Another conditioning ingredient known in such compositions is cationic conditioning polymer. Such polymers are added to compositions in order to provide improved feel to wet and dry hair and particularly to aid in the deposition of hair conditioning oil. Higher charge density are superior deposition agents in conditioning shampoos, as disclosed in US 5,186, 928.
However, excessive deposition of cationic conditioning polymers can lead to undesirable side-effects caused by build-up of material on the hair. This leads to a coated, greasy or unclean feel to the hair for some consumers. US patent application US2001/0012646 Al discloses shampoo compositions providing improved conditioning while reducing undesirable side effects, comprising low charge density cationic polymers which are less efficient as deposition aids, but better than higher charge density polymers for providing wet conditioning benefits. The application specifies cationic polymer hair conditioning agents having a
cationic charge density from 0.1 meq/gm to 1.2 eq/gm, and a molecular weight greater than 600,000.
It has now been discovered that when small particle size waxy opacifiers, typically 5 micrometres or less in diameter, are incorporated into conditioning shampoos, there is a particular problem with obtaining wet conditioning from such shampoos without the side-effect of a greasy, unclean feel to the hair when it is dried.
If the shampoo composition is formulated with anionic and/or amphoteric surfactant and small particle size waxy opacifier, but without cationic hair conditioning polymer, the hair, when wet, can have a squeaky, degreased feel which is repulsive to most consumers, and is prone to tangling. When small waxy opacifier particles are present, the incorporation of cationic conditioning polymers described in the prior art improves the wet feel of the hair, but at the expense of a greasy, unclean feel to the hair when it is dry.
Without being bound by scientific explanation, it is thought that the small particle size waxy opacifier particles are particularly prone to interacting with coacervates formed between cationic polymer and anionic and/or amphoteric cleansing surfactant on dilution, leading to these opacifier particles being deposited onto the hair and causing the unpleasant feel.
Surprisingly, it has been found that shampoo compositions with a milk-like appearance comprising a cleansing
surfactant and small particle size waxy opacifiers can be now provided which have excellent wet hair feel without the side-effect of greasy, unclean feel when the hair is dry. This is achieved by the incorporation of specific cationic polymers into the compositions.
Moreover, in a further aspect of the invention, it has been found that additional conditioning benefits can be obtained from such opacified formulations by the incorporation of liquid hair conditioning oil droplets with a mean particle diameter of 2 micrometres or more. Surprisingly, the hair conditioning oil gives additional conditioning benefits from the opacified compositions of the invention, without a greasy, unclean feel associated with deposited opacifier when the hxair is dry.
In a first aspect, the invention is concerned with a composition for hair cleansing, comprising; i) from 1 % to 50 % by weight of a cleansing surfactant selected from anionic surfactant, amphoteric surfactant, nonionic surfactant and mixtures thereof, ii) 40 % or more by weight of water, iii) from 0.5 % to 15 % by weight of waxy opacifier particles with a mean D3/2 diameter from 0.2 to 5 micrometres and a melting point of 35° C or more, selected from the group consisting of C16-C22
fatty acid, C16-C22 fatty alcohol, mono-, di- and tri- C16-C22 esters of glycerol, mono- and di- Ci6~ C22 esters of ethylene glycol, diethylene glycol and triethylene glycol, C16-C22 fatty a.cid alkanolamides, and mixtures thereof and iv) from 0.01 % to 1 % by weight of a cationically substituted organic polymer,
wherein the cationically substituted organic polymer has a charge density from 0.05 to 1.0 meq/gram and a molecular weight from 10,000 to 500,000 unified mass units .
In a second aspect, the invention concerns compositions as described above which further comprise from 0.01 % to 10 % by weight of droplets of a hair conditioning oil with a melting point of 20°C or less and with a viscosity of 2 -1
2 , 000, 000 mm sec or less at 25°C, wherein the droplets have a mean D3,2 diameter of 2 micrometres or more.
Further aspects of the invention are concerned with methods of washing the hair with the compositions described above, and their use for washing the hair.
All percentages by weight are expressed as percentages of the total composition, unless otherwise specified. Viscosities, unless otherwise indicated, are measured at 25 °C and at shear rates of less than 1 sec"1
Compositions according to the invention comprise waxy opacifier particles in order to provide a mi lky appearance to the composition . Generally, the particle s have a D3 , 2 mean diameter of 6 micrometres or less, pref erably 3 micrometre s or less, more preferably 2 micrometres or less . The mean particle diameter should be greater than 0.2 micrometre s , preferably greater than 0 . 4 micrometres , to ensure su ficient light scattering to provide opacif ication .
A suitable method for measuring the 03 , 2 mean diameter is by laser light scattering using an instrument such as a Malvern Mastersize r .
Suitable waxy opacifiers particles are long chain acyl derivative s selected from the group consisting of C16-C22 fatty acid, C16-C22 fatty alcohol, mono-, di— and tri- C Q-
C22 esters of glycerol, mono- and di- C16-C22 esters of ethylene glycol, diethylene glycol and triethylene glycol, Ci6~C22 fatty acid alkanolamides and mixtures thereof .
The particles are solid at ambient temperatures (10 to 30°C) to provide good opacifying characteristics, hence the melting point of the waxy opacifier is suitably 35°C or more, preferably" 40°C or more, more preferably 45°C or more. By melting point" is meant the temperature at which the waxy opacifier is in a liquid state when heated, as measured by the ASTM D566 dropping point test.
A particularly preferred compound for use as a waxy opacifier is ethylene glycol distearate.
Suitable pre-dispersed aqueous concentrates of waxy emulsifiers are commercially available. An- example is Lamesoft TM Benz (supplied by Cognis containing approximately 25 % by weight Ethylene Glycol Distearate with a mean diameter of 2-4 microns ) .
Suitably, the level of waxy opacifier in compositions according to the invention is from 0.5 % to 15 %, preferably from 1 % to 12 %, more preferably from 3 % to 11 % by weight of the composition.
Compositions according to the invention typically comprise one or more cleansing surfactants which are cosmetically acceptable and suitable for topical application to the hair. The total level of cleansing surfactant in compositions of the invention is suitably from 1 to 50 percent, preferably from 3 to 35 percent, more preferably from 5 to 25 percent by weight of the composition.
Examples of suitable anionic cleansing sur actants are the alkyl sulphates, alkyl ether sulphates, alkaryl sulphonates, alkanoyl isethionates, alkyl succinates, alkyl sulphosuccinates, N-alkyl sarcosinates, alkyl phosphates, alkyl ether phosphates, alkyl ether carboxylates, and alpha- olefin sulphonates, especially their sodium, magnesium, ammonium and mono-, di- and triethanolamine salts. The alkyl and acyl groups generally contain from 8 to 18 carbon atoms and may be unsaturated. The alkyl ether sulphates,
alkyl ether phosphates and alkyl ether carboxylates may contain from 1 to 10 ethylene oxide or propylene oxide units per molecule. Typical anionic cleansing surfactants for use in compositions of the invention include sodium oleyl succinate, ammonium lauryl siilphosuccinate, ammonium lauryl sulphate, sodium dodecylbenzene sulphonate, triethanolamine dodecylbenzene sulphonate, sodium cocoyl isethionate, sodium lauryl isethionate and sodium N-lauryl sarcosinate. The most preferred anionic surfactants are sodium lauryl sulphate, sodium lauryl ether sulphate (n) EO, (where n is from 1 to 3), ammonium lauryl sulphate and ammonium lauryl ether sulphate (n) EO, (where n is from 1 to 3) .
Mixtures of any of the foregoing anionic cl eansing surfactants may also be suitable .
Compositi ons according to the invention may employ amphoteri c, zwitterionic or nonionic surfactants as cleansing surfactants instead of anionic surfactant . However it is preferred if such surfactants are used in combination with an anionic surfactant, as a co-surfactant . A preferred example of co-surfactant is an amphoteric or zwitterionic surfactant, which can be included in an amount ranging from 0 to about 8, preferably from 1 to 4 percent by weight of the composition .
Examples of amphoteric and zwitterionic surfactants include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulp obetaines (sultaines ) , alkyl glycinates, alkyl carjooxyglycinates, alkyl amphopropionates,
alkylamphoglycinates, alkyl amidopropyl hydro ysultaines , acyl ta rates and acyl glutamates, wherein the alkyl and acyl groups have from 8 to 19 carbon atoms . Typica l amphoteric and zwitterionic surfactants for use in shampo os of the invention include lauryl amine oxide, co c o dime thy 1 sulphopropyl betaine and preferably lauryl bet aine, cocamidopropyl betaine and sodium cocamphoprop ionate .
Another preferred example of co-surfactant is a nonionic surfactant, which can be included in an amount ranging from 0 to 8, preferably from 2 to 5 percent by weight of the composition .
For example, representative nonionic surfactants that can be included in shampoo compositions of the invent ion include condensation products of aliphatic (Cs - Cis ) primary or secondary linear or branched chain alcohols or phenols with alkyl ene oxides, usually ethylene oxide and generally having from 6 to 30 ethylene oxide groups .
Other representative nonionic surfactants include mono- or di- alkyl alkanolamides . Examples include coco mono- or di- ethanol amide and coco mono-isopropanolamide .
Further nonionic surfactants which can be included in shampoo compositions of the invention are the alkyl polyglycosides (APGs ) . Typically, the APG is one which comprises an alkyl group connected (optionally via a bridging group) to a block of one or more glycosyl groups . Preferred APGs are defined by the following formula:
RO - ( G ) n
wherein R is a branched or straight chain a lkyl group which may be saturated or unsaturated and G is a saccharide group .
R may represent a mean alkyl chain length o f from about C5 to about -20 - Preferably R represents a mean alkyl chain length of from about Cs to about C12. Most preferably the value of R lies between about 9.5 and about 10 .5. G may be selected from C5 or β monosaccharide residues , and is preferably a glucoside . G may be selected from the group comprising glucose , xylose, lactose, fructose, mannose and derivatives thereof: . Preferably G is glucose .
The degree of polymerisation, n, may have a value of from about 1 to about 10 or more . Preferably, the value of n is from about 1. 1 to about 2 .
Most preferably the value of n is from about 1 .3 to about 1.5.
Suitable alkyl polyglycosides for use in the invention are commercially available and include for example those materials identified as : Oramix NS10 ex Seppic; Plantaren 1200 and Plantaren 2000 ex Henkel .
Other sugar-derived nonionic surfactants which can be included in compositions of the invention include the C10-C18
N-al kyl ( Ci-Cg) polyhydroxy fatty acid amides , such as the Cl2""Ci8 N-methyl glucamides , as described for example in WO 92 06154 and US 5 194 639, and the N-all oxy polyhydroxy fatty acid amides , such as C10-C18 N- ( 3-methoxypropyl ) glucamide .
A preferred blend of surfactants comprises a mixture of ammonium lauryl ether sulfate, ammonium lauryl sulfates , PEG 5 co camide "and cocomide MEA (CTFA designat ions ) .
A cationically substituted organic polymer is an essential ingredient in compositions of the invention. Suitable polymers have a mean molecular weight (weight average, unified atomic mass units) from 10,000 to 500,000, preferably from 30,000 to 400,000, more preferably from 50, O00 to 250, 000.
The cationic charge density of the polymer is suitably measured by the Kjeldahl method. The charge density should be 1.0 meq/gm or less, preferably 0.9 meq/gm or less, more preferably 0.6 meq/gm or less to prevent deposition problems. The charge density should be 0. 05 meq/gm or greater, preferably 0.1 meq/gm or greater, more preferably 0.15 meq/gm or greater to ensure good wet feel to the hair.
The cationic polymer may be a homo-polymer, or be formed from two or more types of monomers. The polymers will have cationic nitrogen containing groups such as quaternary ammonium or protonated a ino groups, or a mixture thereof.
The cationic nitrogen-containing group will generally be present as a substituent on a fraction of the total monomer units of the cationic polymer. Such polymers are described in the CTFA Cosmetic Ingredient Directory, 3rd edition. The ratio of the cationic to non-cationic monomer units is selected to give a polymer having a cationic charge density in the required range.
Suitable cationic conditioning polymers include, for example, copolymers of vinyl monomers having quaternary ammonium functionalities with water soluble spacer monomers such as ( eth) acrylamide, alkyl and dialkyl (meth) acrylamides, alkyl (meth) acrylate, vinyl caprolactone and vinyl pyrrolidine. The alkyl and dialkyl substituted monomers preferably have C1-C7 alkyl groups, more preferably Cl-3 alkyl groups. Other suitable spacers include vinyl esters, vinyl alcohol, maleic anhydride, propylene glycol and ethylene glycol.
Amine substituted vinyl monomers and amines can be polymerised in the amine form and then converted to ammonium by quaternisation.
The cationic conditioning polymers can comprise mixtures of monomer units derived from amine- and/or quaternary ammonium-substituted monomer and/or compatible spacer monomers .
Suitable cationic conditioning polymers include, for example:
— copolymers of l-vinyl-2-pyrrolidine and l-vinyl-3- methyl-imidazolium salt (e.g. chloride salt), referred to in the industry by the Cosmetic, Toiletry, and Fragrance Association, (CTFA) as Polyquaternium-16.
— copolymers of l-vinyl-2-pyrrolidine and dimethylaminoethyl methacrylate, referred to in the industry (CTFA) as Polyquaternium-11. — cationic diallyl quaternary ammonium-containing polymers including, for example, copolymers of acrylamide and dimethyldiallylammonium chloride, referred to in the industry (CTFA) as Polyquaterniu 6 and Polyquaternium 7, respectively;
— mineral acid salts of amino-alkyl esters of co-polymers of unsaturated carboxylic acids having from 3 to 5 carbon atoms, (as described in U.S. Patent 4,009,256);
— cationic polyacrylamides (as described in W095/22311).
Other cationic conditioning polymers that can be used include cationic polysaccharide polymers, such as cationic cellulose derivatives, cationic starch derivatives, and cationic guar gum derivatives.
Cationic polysaccharide polymers suitable for use in compositions of the invention include those comprising monomers according to the formula:
A-0-[R-N+(R1) !R ) (R )X ],
wherein: A is an anhydroglucose residual group, such as a starch or cellulose anhydroglucose residual. R is an alkylene, oxyalkylene, polyoxyalkylene, or hydroxyalkylene 1 2 3 group, or combination thereof. R , R and R independently represent alkyl, aryl, alkylaryl, arylalkyl, alkoxyalkyl, or alkoxyaryl groups, each group containing up to about 18 carbon atoms. The total number of carbon atoms for each 1 ? cationic moiety (i.e., the sum of carbon atoms in R , R and 3 R ) is preferably about 20 or less, and X is an anionic counterion.
Cationic cellulose is available from A erchol Corp. (Edison, NJ, USA) in their Polymer LR (trade mark) series of polymers, as salts of hydroxyethyl cellulose reacted with trimethyl ammonium substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 10. Another type of cationic cellulose includes the polymeric quaternary ammonium salts of hydroxyethyl cellulose reacted with lauryl dimethyl ammonium-substituted epocide, referred to in the industry (CTFA) as Polyquaternium 24. These materials are available from Amerchol Corp. (Edison, NJ, USA) under the tradename Polymer LM-200.
Other suitable cationic polysaccharide polymers include quaternary nitrogen-containing cellulose ethers (e.g. as described in U.S. Patent 3,962,418), and copolymers of etherified cellulose and starch (e.g. as described in U.S. Patent 3,958,581).
Another type of cationic polys ccharide polymer that may be used in compositions according to the invention is a cationic guar gum derivative, such as guar hydroxypropyltrimonium chloride (commercially available from Rhone-Poulenc in their JAGUAR trademark series) . However, it has been found that cationic guar gum derivatives are less suitable for compositions of the invention than the other cationically substituted polymers detailed above, because although they provide good wet feel to the hair, they can give more of a greasy feel to the hair when dry than the other, preferred polymer types.
Particularly preferred cationically substituted organic polymers for compositions according to the invention are cationically substituted celluloses, alkyl celluloses, hydroxy alkyl celluloses and alkyl hydroxy alkyl celluloses. Mixtures of these polymers are also suitable.
An example of a suitable polymer for use in compositions of the invention is the polymer Qαiatrisoft LM 200 which is a cationically substituted hydrophobically modified hydroxyethyl cellulose with a mean molecular weight of from 200,000 to 300,000 and a charqe density of approximately 0.2 meq/gm (0.35 to 0.34 % by weight of nitrogen). Another suitable polymer is Polymer LR 400 which is a cationically modified hydroxyethyl cellulose with a molecular weight of approximately 400,000 and a charge density of 0.8 meq/gm (0.8 to 1.1% by weight of nitrogen) . Polymer LK s also suitable. It is structurally similar to LR 400, with the same molecular weight, but has lower charge density (0.4 meq/gm
corresponding to 0.4 % to 0.6 % by weight of nitrogen) . These polymers are commercially available from Amerchol.
The cationically substituted organic polymer should be present in compositions of the invention at levels of from 0.01 to 1, preferably from 0.03 to 0.5, more preferably from 0.05 to 0.2 percent by weight of the composition.
A component of compositions according to the second aspect of the invention is a hydrophobic silicone conditioning oil. In order for such an oil to exist in discrete droplets in the compositions according to the invention, it must be water- insoluble. By water-insoluble is meant that the solubility in water at 25°C is 0.01 % by weight or less.
It is necessary that the D3f2 mean particle diameter of the hydrophobic conditioning oil droplets in the composition is 2 micrometres or more, preferably 5 micrometres or more, and more preferably 8 micrometres or more, in order to obtain adequate substantivity of the silicone onto the hair from the cleansing composition. The mean particle diameter of the oil droplets in the composition is 100 micrometres or less, preferably 50 micrometres or less to prevent problems in stabilising the composition from phase separation of components.
The oil D3Λ2 mean droplet diameter may be measured by means of a laser light scattering technique, for example using a 2600D Particle Sizer from Malvern Instruments.
The total amount of conditioning oil present in the composition is preferably from 0.01 % to 10 % by weight of the total composition more preferably from 0.3 % to 5 %, most preferably 0.5 % to 3 %.
Silicones are particularly preferred as hair conditioning oils for use in compositions according to the invention.
Suitable silicones for use as conditioning oils include polydiorganosiloxanes, in particular polydimethylsiloxanes which have the CTFA designation dimethicone. Also suitable for use compositions of the invention are polydimethyl siloxanes having hydroxyl end groups, which have the CTFA designation dimethiconol .
It is preferred if the silicone oil also comprises a functionalised silicone. Suitable functionalised silicones include, for example, amino-, carboxy-, betaine-, quaternary ammonium-, carbohydrate-, hydroxy- and alkoxy-substituted silicones. Preferably, the functionalised silicone contains multiple substitutions.
For the avoidance of doubt, as regards hydroxyl-substituted silicones, a polydimethylsiloxane merely having hydroxyl end groups (which have the CTFA designation dimethiconol) is not considered a functionalised silicone within the present invention. However, a polydimethylsiloxane having hydroxyl substitutions along the polymer chain is considered a functionalised silicone.
Preferred functionalised silicones are amino-functionalised silicones. Suitable amino functionalised silicones are described in EP 455,185 (Helene Curtis) and include trimethylsilylamodimethicone as depicted below, and are sufficiently water insoluble so as to be useful in compositions of the invention:
Si(CH3)3-0 -[Si(CH3) 2-0-]χ-[Si (CH3) (R-NH-CH2CH2NH2) -0-]y - Si (CH3)3
wherein x + y is a number from about 50 to about 500, and the weight percent amine functionality is from about 0.03 % to about 8 %, and wherein R is an alkylene group having from 2 to 5 carbon atoms . Preferably, the number x + y is in the from 100 to 300, and the weight percent amine functionality is from about 0.03 % to 8 %.
As expressed here, the weight percent amine functionality is measured by titrating a sample of the amino-functionalised silicone against alcoholic hydrochloric acid to the bromocresol green end point. The weight percent amine is calculated using a molecular weight of 45 (corresponding to
CH3-CH2-NH2) .
Suitably, the wei ght percent amine functionality mea sured and calculated in this way is from 0 . 03 % to 8 % , pr eferably from 0.5 % to 4 % .
An example of a commercially available amino-functionalised silicone useful in the silicone component of the composition
of the invention is DC-8566 available from Dow Corning (INCI name: dimethyl, methyl (aminoethylaminoisobutyl) siloxane) . This has a weight percent amine functionality of about 1.4%.
By "a ino functional silicone" is meant a silicone containing at least one primary, secondary or tertiary amine group, or a quaternary ammonium group. Examples of suitable amino functional silicones include polysiloxanes having the CTFA designation "amodimethicone" . Specific examples of amino functional silicones suitable for use in the invention are the aminosilicone oils DC-8220, DC-8166, DC-8466, and DC-8950-114 (all ex Dow Corning), and GE 1149-75, (ex General Electric Silicones). Suitable quaternary silicone polymers are described in EP-A-0 530 974. A preferred quaternary silicone polymer is K3474, ex Goldschmidt.
Another preferred functional silicone for use as a component in the hydrophobic conditioning oil is an alkoxy-substituted silicone- Such molecules are known as silicone copolyols, and have one or more polyethyleneoxide or polypropyleneoxide groups bonded to the silicone polymer backbone, optionally through an alkyl linking group.
A non-limiting example of a type of silicone copolyol useful in compositions of the invention has a molecular structure according to the formula depicted below:
Si(CH3)3[0-Si(CH3) (A)]p-[0-Si(CH3) (B) ] g-O-Si (CH3) 3
In this formula, A is an alkylene chain with from 1 to 22 carbon atoms, preferably 4 to 18, more preferably 10 to 16. B is a group with the structure: - (R) — (EO) r (PO) S-0H wherein R is a linking group, preferably an alkylene group with 1 to 3 carbon atoms. Preferably R is -(CH2)2~« The mean values of r and s are 5 or more, preferably 10 or more, more preferably 15 or more.
It is preferred if the mean values of r and s are 100 or less. In the formula, the value of p is suitably 10 or more, preferably 20 or more, more preferably 50 or more and most preferably 100 or more. The value of q is suitably from 1 to 20 wherein the ratio p/q is preferably 10 or more, more preferably 20 or more. The value of p + q is a number from 11 to 500, preferably from 50 to 300.
Suitable silicone copolyols have an HLB of 10 or less, preferably 7 or less, more preferably 4 or less. A suitable silicone copolyol material is DC5200, known as Lauryl PEG/PPG - 18/18 ethicone (INCI name), available from Dow Corning.
Hydrophile/Lipophile balance or HLB is a well known parameter used by those skilled in the art to characterise surface active molecules and emulsifiers.
Suitable methods for the experimental determination of HLB are in Griffin W.C, Journal of the Society of Cosmetic Chemists, volume 1 page 311 (1949) . The commercially
available silicone copolyols are supplied along with a value of their HLB by Dow Corning.
It is preferred to use a combination of functional and non- functional silicones as the conditioning oil. Preferably these are blended into common droplets prior to incorporation into compositions according to the invention.
The viscosity of the silicone oil blend measured in isolation from the rest of the composition (i.e. not the viscosity of any pre-formed emulsion, but of the silicone blend forming the hydrophobic conditioning oil) is suitably from 1,000 to
2,000,000 mm sec at 25 C, preferably from 5,000 to
1,000,000, more preferably from 10,000 to 500,000, most preferably from 50,000 to 300,000. Suitable methods for measuring the kinematic viscosity of silicone oils are known to those skilled in the art, e.g. capillary viscometers as described in Dow Corning test method CTM 0004.
For high viscosity silicones, a constant stress rheometer can also be used to measure viscosity.
Compositions (especially washing compositions) according to the invention will have 40 % or more water by weight of composition. The form of the compositions is as an aqueous solution of surfactant with the waxy opacifier particles, and any silicone hair conditioning oil dispersed and suspended in the solution. The pH of compositions according to the invention will suitably be from 3 to 8, preferably from 4 to 7.
The compositions are suitably used to wash the hair by applying an aliquot of the composition to the hand or hair, lathering and rubbing, followed by rinsing with clean water . /Another aspect of the invention is a method of cleansing the hair by applying to it the compositions according to the invention, followed by lathering and rinsing .
Another aspect of the invention is the use of compositions according to the invention to cleanse the hair and to provide wet conditioning without a dull greasy feel to the dried hair .
Typically, compositions according to the invention will have their viscosity modified to improve stability to phase separation by the addition of salt such as sodium chloride . They may also comprise other suspending agents .
Preferably, the compositions according to the invention further comprise from 0 . 1 to 10 percent, preferably from 0 . 6 to 6 percent by weight of the composition, of a suspending agent . The role of the suspending agent is to further inhibit the phase separation of the dispersed ingredients in the composition .
Suitable suspending agents are selected from polyacrylic acids, cross-linked polymers of acrylic acid, copo lymers 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 . Polyacrylic acid is availabl e commercially as Carbopol 420, Carbopol 488 or Carbopol 493 .
Pol ymers of acrylic acid cross-linked with a polyfunctional agent, known as cross-linked polyacryl ates , may also be use d, they are available commercially as Carbopol 910, Carbopol 934, Carbopol 940, Carbopol 941 and Carbopol 980 . An example of a suitable copolymer of a carboxylic acid containing a monomer and acrylic acid esters is Carbopol 1342 . All Carbopol (trade mark) mater ials are available from Goodrich . The CTFA designation for cross-linked pol yacrylates is Carbomer .
Sui table cross-linked polymers of acrylic acid and acrylate esters are Pemulen TR1 or Pemulen TR2. A suitable het eropolysaccharide gum is xanthan gum, for example that available as Kelzan mu .
Compositions of this invention may contain any other ingredient normally used in hair treatment formulations . The se other ingredients may include vi scosity modifiers, pre servatives , colouring agents , polyo ls such as glycerine and polypropylene glycol, chelating agents such as EDTA, antioxidants , fragrances, antimicrobia ls and sunscreens . Each of these ingredients will be pres ent in an amount effective to accomplish its purpose . Generally these optional ingredients are included individually at a level of up to 5 % by weight of the total compo sition .
Examples
Low charge density cationic polymers and small EGDS opacifier particles + large particle size silicone in shampoo
All test shampoos comprise the following base formulation:
14% anionic surfactant (SLES 2EO) 2% amphoteric surfactant (CAPB) 0.6% suspending agent (Carbopol 980) 0.5% fragrance 0.2% preservative 1% salt 1 % lOum 60kcS PDMS emulsion (DC-1310) 2% small EGDS particles (La esoft TM) Balance water
As indicated below, test shampoo formulations were prepared comprising cationic polymers (Quatrisoft LM200, Polymer LK, Polymer LR30M, Jaguar C17) at a level of 0.2 %.
Test shampoos containing Polymer LK and Quatrisoft LM.200 are according to the invention, whereas shampoos containing Jaguar C17, Polymer LR30M or no polymer (i.e. the shampoo base alone) are not according to the invention.
The shampoo formulations were tested using a sensory test based on 7g switches of dark brown European hair. The wet switches were treated with 0.7g of shampoo before lathering thoroughly for 30 seconds. After a 30 second rinse, the application, lathering and rinsing process was repeated. Wet stage attributes were assessed at this point. Dry stage attributes were assessed after thorough drying under ambient conditions . In each of the tests, treated switches were assessed by 10 independent panellists and allocated a score on a line scale ranging from 0 to 1000. The data shown in the following charts are mean values for each of the treated switches. The standard error in the mean (the standard deviation divided by the square root of the number of degrees of freedom in the experiment) is shown as the error bar and used to infer significance .
Test 1 - Smoothness (wet stage)
Shampoo C (which is according to the invention) was tested against the Base and against shampoo B (neither of which are according to the invention) . The washed switches were assessed by 10 independent panellists for smoothness in the wet stage. The mean scores are shown in figure 1.
For hair smoothness in the wet stage, both shampoo C and shampoo B are superior to the Base formulation. Shampoo C and shampoo B are essentially at parity. Test 2 - Squeakiness (wet stage)
Shampoo D (which is according to the invention) was tested against the Base and against shampoo B (neither of which are according to the invention) . The washed switches were assessed by 10 independent panellists for squeakiness in the wet stage. The mean scores are shown in figure 2.
For hair squeakiness in the wet stage, both shampoo D and shampoo B have parity with the Base formulation. Directionally, shampoo D is the least squeaky treatment.
Test 3 - Volume (dry stage)
Shampoo C (which is according to the invention) was tested against shampoo A and shampoo B (neither of which are according to the invention) . The washed switches were dried then assessed by 10 independent panellists for volume. The mean scores are shown in figure 3.
For hair volume in the dry stage, shampoo C is superior to both shampoo A and shampoo B. Shampoo B is superior to shampoo A.
Test 4 - Greasiness (dry stage)
Shampoo D (which is according to the invention) was tested against shampoo A and shampoo B (neither of which are according to the invention). The washed switches were dried then assessed by 10 independent panellists for greasiness. The mean scores are shown in figure 4.
For hair greasiness in the dry stage, shampoo D is superior to both shampoo A and shampoo B. Shampoo B is parity to shampoo A.
Summary
The formulations according to the invention (shampoo C and shampoo D) are superior to the Base formulation in the wet stage and superior to shampoo A in the dry stage. Shampoo B, another formulation which is not according to the invent ion, is parity to shampoos C and D in the wet stage but inferior to shampoos C and D in the dry stage.