Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions
Reexamination Certificate
1999-04-19
2004-03-16
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
C424S070110, C424S070120, C424S070210, C424S070220, C424S070400, C424S401000, C424S404000, C514S063000, C514S852000, C514S880000, C514S881000, C510S122000, C510S123000
Reexamination Certificate
active
06706258
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to shampoo compositions, and more particularly to shampoo compositions containing emulsified particles of silicone, which compositions condition the hair leaving it softer and more manageable.
BACKGROUND AND PRIOR ART
The use of silicones as conditioning agents in cosmetic formulations is well known and widely documented in the patent literature. Generally, dispersed droplets of the silicone oil are suspended in the composition, which is then applied to the hair to deposit the silicone material on the hair shaft.
A typical method of silicone shampoo manufacture is disclosed in WO 92/10162. Essentially, the silicone material is emulsified directly into the shampoo by an in situ hot process, in which the complete shampoo mixture incorporating the silicone is mixed thoroughly at elevated temperature, pumped through a high shear mill and then cooled. The silicone can be dispersed in a first process stage with anionic surfactant and fatty alcohol to form a premix. The premix is then mixed with the remaining materials of the shampoo, pumped through a high shear mill, and cooled to obtain the final composition.
A disadvantage associated with an in situ hot process such as is described in WO 92/10162 is that factory handling of viscous silicone oil is difficult in the context of a full shampoo manufacturing operation.
A further disadvantage is that special equipment is normally needed to control silicone particle size during manufacture. GB 2 170 216 A discloses a similar process, in which the full shampoo composition incorporating insoluble, non-volatile silicone is sheared with a high shear mixer until the silicone particles are on average less than 2 microns in diameter. The particle size distribution is then said to be from about 2 to about 55 microns.
In order to solve the above mentioned problems with in situ hot processing of silicone, the alternative of incorporating the silicone as a preformed aqueous emulsion has been proposed. Such a method has the consequences that the silicone is incorporated with a predeterminable, controllable particle size distribution. The silicone is insoluble and remains emulsified in the fully formulated shampoo composition, and thus the step of high shear processing of the silicone within the fully formulated shampoo composition is not required. This also makes manufacture of the compositions easier.
A typical method for incorporating insoluble, non-volatile silicone materials into a conditioning shampoo is disclosed in U.S. Pat. No. 5,085,087 in which such materials are incorporated in the shampoo composition as a pre-formed aqueous emulsion of average particle size less than 2 microns. All the ingredients are mixed in a simple hot or cold process in which the average particle size of the silicone material in the emulsion remains the same in the final shampoo composition.
EP 0 529 883 A1 discloses hair shampoo compositions made by an equivalent method and comprising microemulsified particles of silicone having a particle size of 0.15 microns or less, e.g., 0.036 microns. Reducing the silicone particle size still further in this way is said to improve stability, optical properties and conditioning performance. In particular, the small particle size of these silicone microemulsions means that a suspending system (such as waxy materials, inorganic particles and/or polymeric thickeners) is not required. Also, these silicone microemulsions do not scatter light and can be used for formulating transparent products. The silicone emulsions disclosed in U.S. Pat. No. 5,085,087 are not microemulsions and require a suspending system in the shampoo.
A problem encountered with the above formulations is that the conditioning performance may be insufficient for many people, particularly in regions such as Japan and South East Asia where consumers desire a high level-of conditioning and a “weighty” feel to their hair.
We have now found that the conditioning performance of silicone in a surfactant-based shampoo composition can be significantly boosted by utilising a combination of emulsified silicone and microemulsified silicone, in the shampoo composition.
Advantageously, we have also found that this offers a route to enhanced deposition of other benefit agents such as solid active agents.
SUMMARY OF THE INVENTION
The invention provides an aqueous shampoo composition comprising, in addition to water:
i) at least one cleansing surfactant;
ii) a cationic deposition polymer, and
iii) a silicone component consisting of a blend of:
(a) emulsified particles of an insoluble silicone, in which the emulsified particles of insoluble silicone are incorporated into the shampoo composition as a preformed aqueous emulsion having an average silicone particle size in the emulsion and in the shampoo composition of from 0.15 to 30 microns, and
(b) microemulsified particles of an insoluble silicone, in which the microemulsified particles of insoluble silicone are incorporated into the shampoo composition as a preformed aqueous microemulsion having an average silicone particle size in the microemulsion and in the shampoo composition of less than 0.10 microns.
DETAILED DESCRIPTION OF THE INVENTION
Silicone Component
The silicone component consists of a blend of emulsified particles of insoluble silicone of specified average silicone particle size and microemulsified particles of insoluble silicone of specified average silicone particle size.
The silicones are insoluble in the aqueous matrix of the shampoo composition and so are present in emulsified and microemulsified forms respectively, with the silicones present as dispersed particles.
Particle size may be measured by means of a laser light scattering technique, using a 2600D Particle Sizer from Malvern Instruments. The measure of average particle size using this technique is the “D50” value.
Suitable silicones for the silicone component include polydiorganosiloxanes, in particular polydimethylsiloxanes which have the CTFA designation dimethicone. Aminofunctional silicones which have the CTFA designation amodimethicone, are also suitable for use in the compositions of the invention, as are polydimethyl siloxanes having hydroxyl end groups, which have the CTFA designation dimethiconol. Also suitable for use are silicone gums having a slight degree of cross-linking, as are described for example in WO 96/31188. These materials can impart body, volume and stylability to hair, as well as good wet and dry conditioning.
The emulsified particles of insoluble silicone may be of the same silicone type as the microemulsified particles of insoluble silicone, or may be different.
Suitable silicone emulsions and microemulsions for use in the invention are commercially available in a pre-emulsified form. Such pre-formed emulsions can then be incorporated into the shampoo composition by simple mixing, which is particularly advantageous for ease of processing. Pre-formed emulsions are available from suppliers of silicone oils such as Dow Corning, General Electric, Union Carbide, Wacker Chemie, Shin Etsu, Toshiba, Toyo Beauty Co, and Toray Silicone Co.
An aqueous emulsion is the preferred form for such a pre-formed emulsion. In such emulsions, it is usual that the emulsion additionally includes at least one emulsifier in order to stabilise the silicone emulsion.
Suitable emulsifiers are well known in the art and include anionic and nonionic surfactants. Examples of anionic surfactants used as emulsifiers for the silicone particles are alkylarylsulphonates, e.g., sodium dodecylbenzene sulphonate, alkyl sulphates e.g., sodium lauryl sulphate, alkyl ether sulphates, e.g., sodium lauryl ether sulphate nEO, where n is from 1 to 20 alkylphenol ether sulphates, e.g., octylphenol ether sulphate nEO where n is from 1 to 20, and sulphosuccinates, e.g., sodium dioctylsulphosuccinate.
Examples of nonionic surfactants used as emulsifiers for the silicone particles are alkylphenol ethoxylates, e.g., nonylphenol ethoxylate nEO, where n is from 1 to 50, alcohol ethoxylates, e.g., lauryl alcohol nEO, where n is from 1
Gallagher Peter
Kreu-Nopakun Tipawan
Murray Andrew Malcolm
Channavajjala Lakshmi
Honig Milton L.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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