Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-03-22
2003-04-15
Pryor, Alton (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C514S063000
Reexamination Certificate
active
06548074
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to silicone elastomer cosmetic emulsions stabilized against separation.
2. The Related Art
Cosmetic emulsions of silicone elastomers have become quite popular in cosmetic formulations.
U.S. Pat. No. 5,387,417 (Rentsch) reports obtaining cosmetically acceptable, translucent moisturizing lotions through emulsification of a petrolatum base with a crosslinked organopolysiloxane-polyoxyalkylene emulsifier. According to the disclosure, not only is compatibility achieved but this siloxane allows for matching of refractive indices for the continuous and discontinuous phases.
U.S. Pat. No. 5,280,019 (Klimisch) reports compositions which enhance the absorption and retention of moisturizer on the skin. These results are achieved through use of an organosilicon compound which is a carboxy functionalized polysiloxane or its metal carboxylate salt.
U.S. Pat. No. 5,833,973 (Dobkowski) describes crosslinked elastomeric silicones in aqueous emulsion cosmetic compositions. Inclusion of the elastomer provides a unique liquid/powdery feel when rubbed into the skin.
WO 97/32561 (Nawaz et al.) reports a skincare composition which includes a silicone-containing phase with a crosslinked polyorganosiloxane polymer and silicone oil, an organic liquid crystal-forming amphiphilic surfactant and water.
Emulsions generally have phase stability problems. Some silicone elastomers can improve phase stability. Nevertheless there still remains significant area for improvement.
Accordingly, it is an object of the present invention to provide a cosmetic composition in emulsion form which exhibits good phase stability.
Another object of the present invention is to provide a cosmetic composition in emulsion form which provides improved skinfeel properties.
Still another object of the present invention is to provide a cosmetic composition in emulsion form which is self preserving without requiring the addition of standard preservatives.
These and other objects of the present invention will become more readily apparent from the following summary and detailed description.
SUMMARY OF THE INVENTION
A cosmetic composition is provided which includes:
(i) from about 0.1 to about 30% of a polysiloxane elastomer;
(ii) from about 5 to about 80% of a volatile siloxane;
(iii) from about 10 to about 95% by weight of water; and
(iv) from about 0.1 to about 40% by weight of pentylene glycol.
DETAILED DESCRIPTION OF THE INVENTION
Now it has been found that pentylene glycol can stabilize an emulsion combination of silicone elastomer, volatile cyclomethicone and water.
Polysiloxane elastomers are a first essential element of this invention. Advantageously these elastomers will be of the crosslinked type. Even more preferably the elastomers are non-emulsifying although the invention is considered broader than these particular materials. They will have an average number molecular weight in excess of 2,000, preferably in excess of 1,000,000 and optimally will range from 10,000 to 20 million. The term “non-emulsifying” defines a siloxane from which polyoxyalkylene units are absent. Advantageously the elastomers are formed from a divinyl compound, particularly a polymer with at least two free vinyl groups, reacting with Si—H linkages of a polysiloxane backbone such as a molecularly spherical MQ resin. Elastomer compositions are commercially available from the General Electric Company under product designation General Electric Silicone 1229 with proposed CTFA name of Cyclomethicone and Dimethicohe/Vinyl Dimethicone Cross Polymer, delivered as 20-35% elastomer in a cyclomethitcone carrier. A related elastomer composition under the CTFA name of Crosslinked Stea Methyl Dimethyl Siloxane Coplymer is available from Grant Industries, Inc., Elmwood Park, N.J. A still further commercial source for polysiloxane elastomers is available from the Dow Corning Company under the product designation DC 9090, which blends silicone elastomer powder with cyclomethicone.
Amounts of the elastomer may range from about 0.1 to about 30%, optimally from about 1 to about 15%, most preferably from about 3 to about 10% by weight.
A second essential element of the present invention is that of a volatile siloxane. The term “volatile” refers to those materials having a measurable pressure at ambient conditions. Volatile polyorganosiloxanes useful herein may be cyclic or linear. Preferred cyclic silicones include polydimethylsiloxanes containing from about 3 to about 9 silicon Atoms, preferably containing from about 4 to about 5 silicon atoms, generally known as Cyclomethicones. Preferred linear silicone oils include the polydimethylsiloxanes containing from about 3 to about 9 silicon atoms. The linear volatile silicones generally have viscosities of less than about 5 centistokes at 25° C. while the cyclic materials have viscosities of less than about 10 centistokes, the preferable range being from 0.1 to 8 centistokes. Examples of silicone oils useful in the present invention include: Dow Corning 244, Dow Corning 245, Dow Corning 344, Dow Corning 345 and Dow Corning 200 (manufactured by the Dow Corning Corporation); Silicone 7207 and Silicone 7158 C manufactured by the Union Carbide Corporation); and SF1202 (manufactured by the General Electric Company).
Amounts of the volatile siloxane may range from about 5 to about 80%, preferably from about 15 to about 70%, optimally from about 30 to about 65% by weight.
Cosmetic compositions of the present invention will contain substantial levels of water. Emulsions of the present invention will contain water in amounts ranging from about 10 to about 95%, preferably from about 25 to about 80%, optimally from about 35% to about 65% by weight. The emulsions may be of the oil-in-water, water-in-oil or duplex variety. Most especially, the invention is concerned with the water-in-oil variety. Aqueous to oily phases will range in weight from about 10:1 to about 1:10, preferably from about 1:1 to about 2:1, optimally from about 1:1 to about 1.5:1.
Most preferable for the present invention are water-in-oil emulsions having a high internal (water) phase volume.
A final essential element of the compositions according to this invention is pentylene glycol. This material is chemically known as 1,2-pentanediol and available from Dragoco under the trademark Hydrolite-5. Amounts of pentylene glycol may range from about 0.1 to about 40%, preferably from about 0.8 to about 20%, optimally from 1 to about 8% by weight.
Compositions of the invention may optionally contain a skin conditioning agent. The agents may be selected from humectants, exfoliants or emollients.
Humectants are polyhydric alcohols intended for moisturizing, reducing scaling and stimulating removal of built-up scale from the skin. Typical polyhydric alcohols include polyalkylene glycols and more preferably alkylene polyols and their derivatives. Illustrative are propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerin, propoxylated glycerin and mixtures thereof. Most preferably the humectant is glycerin. Amounts of humectant may range anywhere from about 1 to about 50%, preferably from about 10 to about 40%, optimally from about 25 to about 35% by weight.
Exfoliants according to the present invention may be selected from alpha-hydroxycarboxylic acids, beta-hydroxycarboxylic acids and salts of these acids. Most preferred are glycolic, lactic and salicylic acids and their ammonium or alkali metal salts.
When the conditioning agent is an emollient it may be selected from hydrocarbons, fatty acids, fatty alcohols and esters. Petrolatum is the most preferred hydrocarbon type of emollient conditioning agent. Other hydrocarbons that may be employed include mineral oil, polyolefins such as polydecene, and paraffins such as isohexadecane (e.g. Permethyl 99® and Permethyl 101®).
Fatty acids and alcohols will have from 10 to 30 carbon atoms. Illustrative of this category are pelargo
Dubno Herbert
Elizabeth Arden Co., division of Conopco, Inc.
Pryor Alton
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