Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
1999-05-10
2001-08-21
Warden, Jill (Department: 1743)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C516S053000, C516S071000, C516S072000, C516S076000, C424S070130, C514S060000, C514S844000
Reexamination Certificate
active
06277893
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to stable oil-in-water emulsions for use in cosmetic compositions comprising an oil phase which contains the combination of a polysaccharide such as an amino-multicarboxylate starch derivative and a dimethicone copolyol as an emulsifier, and a water phase.
Emulsions are two phase systems consisting of two incompletely miscible liquids, one being dispersed in the other. The most common emulsions are those of oil and water and there are two types of emulsions, namely those in which oil globules are dispersed in water (“oil-in-water” emulsions) and those in which water globules are dispersed in oil (“water-in-oil” emulsions). The present invention involves oil-in-water type emulsions, i.e., where water is the continuous phase and oil is the dispersed or discontinuous phase.
Oil-in-water type emulsions are widely used in cosmetic and dermatolgical compositions or applications, particularly skin, hair and body care compositions, because they help provide aesthetic and appearance characteristics such as gentleness and feel. However, these oil-in-water emulsions often contain well known or classical type surfactants or emulsifying agents which can cause skin irritation or allergic reactions and also may not be compatible with other constituents in the emulsion formulation.
Accordingly, what is desired is an oil-in-water emulsion which is stable and compatible and avoids causing problems such as skin irritations and allergic reactions and are especially useful in cosmetic compositions.
SUMMARY OF THE INVENTION
This invention relates to stable oil-in-water emulsions which are useful in cosmetic compositions and comprises an oil phase that contains the combination of a polysaccharide such as an amino-multicarboxylate starch derivative and a dimethicone copolyol as an emulsifier, and a water phase.
More particularly, this invention is directed to an oil-in-water emulsion comprising an oil phase which contains the combination of:
a) from about 0.1 to 95% by weight, based on the weight of emulsion, of a polysaccharide selected from the group consisting of an amino-multicarboxylate starch derivative, xanthan gum, hydroxyethyl cellulose and hydroxypropyl starch phosphate, the amino-multicarboxylate starch derivative having the following structure:
wherein
ST-O represents a starch molecule or a modified starch molecule (wherein the hydrogen of a hydroxy group of an anhydroglucose unit has been replaced as shown);
R is H or CH
3
;
R′ is H, CH
3
or COOM
M is a cation selected from the group consisting of H, alkali metal, alkaline earth metal and ammonium:
n is 2 or 3; and
R″ is H or alkyl of 1 to 18 carbon atoms; and
b) from about 0.1 to 50% by weight, based on the weight of emulsion, of a dimethicone copolyol having the following formula:
where I is 0 to 300, m is 1 to 40, y is 4 to 40, z is 0 to 40 and the weight ratio of y:z is from about 100:0 to about 0:100, and R is selected from hydrogen, alkyl, alkoxy and acyl groups having from about 1 to 16 carbon atoms, and a water phase.
This invention also covers a cosmetic composition comprising an oil-in-water emulsion wherein the oil phase contains the combination of a) polysaccharide selected from the group consisting of an amino-multicarboxylate starch derivative, xanthan gum, hydroxyethyl cellulose and hydroxypropyl starch phosphate and b) a dimethicone copolyol as an emulsifier, as defined above and in further detail in this application.
DESCRIPTION OF THE INVENTION
The oil-in-water emulsion of this invention contains the combination of a selected polysaccharide and a dimethicone copolyol as an emulsifier in the oil phase and a water phase. The combination of polysaccharide and dimethicone copolyol when used in the oil phase provides emulsification for the oil-in-water emulsions of this invention and replaces the conventional and known emulsifiers that have been used in typical emulsion compositions. The polysaccharide as used in this invention may be a starch, gum, cellulose or derivative thereof. The starch may be any of several starches, native or converted. Such starches include those derived from any plant source including corn, potato, wheat, tapioca, rice, sago, sorghum, waxy starches such as waxy maize, waxy potato and waxy rice, and high amylose starch such as high amylose corn, i.e., starch having at least 40% and more particularly at least 65% amylose content by weight. Also included are the conversion products derived from any of the former bases such as for example, dextrins prepared by hydrolytic action of acid and/or heat, fluidity or thin boiling starches prepared by enzyme conversion or mild acid hydrolysis and oxidized starches prepared by treatment with oxidants such as sodium hypochlorite. Also included are the derivatized starches such as the hydroxy alkylated or etherified starches, e.g., hydroxypropyl, the esterified starches such as acetylated, cationic and anionic starches, and crosslinked starches. The polysaccharide gums that are useful include xanthan gum, guar gum, locust bean gum, taramind, gum arabic, alginates and gellan. The useful cellulose materials include cellulose and cellulose derivatives such as carboxyalkyl cellulose and hydroxyalkyl cellulose and particularly those having an alkyl of 1 to 4 carbon atoms.
Particularly useful polysaccharide include those selected from the group consisting of an amino-multicarboxylate starch derivative, xanthan gum, hydroxyethyl cellulose and hydroxypropyl starch phosphate. Preferably the polysaccharide is an amino-multicarboxylate starch derivative having one of the structures, I or la, as previously described. These starch derivatives can be prepared by reacting starch with selected amino-multicarboxylic acid reagents as described in U.S. Pat. No. 5,482,704 issued to R. W. Sweger et al. on Jan. 6, 1996. The amino-multicarboxylic acid reagents have the following formula:
where X is halogen, R is H or CH
3
, R′ is H, CH
3
or COOM, n is 2 or 3 and R″ is H or alkyl of 1 to 18 carbon atoms.
The reagents III and IIIa as defined above are provided by a Michael reaction between an aminoalcohol and a selected ester containing an activated olefin followed by halogenation. The formation involves reacting the selected multicarboxylate reagent III or IIIa with a starch base in an aqueous medium using either an aqueous slurry or an aqueous dispersion of the starch base. Further description of the preparation of the amino-multicarboxylate starch derivatives can be found in the above noted U.S. Pat. No. 5,482,704 which is incorporated herein by reference.
The applicable starch bases which may be used in preparing the amino-multicarboyxlate starch ether derivatives I and Ia may be derived from any plant source including corn, potato, wheat, rich, sago, tapioca, waxy maize, sorghum, oat, high amylose starch, i.e., starch having amylose content of greater than about 45% by weight such as high amylose corn, etc. Also included are the conversion products derived from any of the latter bases including, for example, dextrins prepared by the hydroyses of acid and/or heat; oxidized starches prepared by treatment with oxidants such as sodium hypochlorite; fluidity or thin-boiling starches prepared by enzyme conversion or mild acid hydrolyses; and derivatized starches such as ethers and esters. Starch esters will undergo hydrolyses when exposed to reaction conditions needed to prepare starch ethers. If mixed starch ethers/esters are desired, it is obvious to those skilled in the art that the ether substituents must be reacted first, followed by esterification. The intermediate starch ether can be directly esterified or isolated and purified prior to esterification. The starch base may be a granular starch or a gelatinized starch, i.e., non-granular starch.
The preferred starch derivatives I and Ia of this invention as described above, are those wherein R, R′ and R″ are hydrogen, M is hydrogen and n is 2 and more particularly those having the structure I. The starch base is preferably potato starch. Also
Cole Monique T.
Duncan Laurelee A.
National Starch & Chemical Co. Investment Holding Corporation
Warden Jill
Zegarella Eugene
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