Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-03-13
2001-10-09
Zitomer, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C424S078220, C424S078240, C526S213000, C526S218100, C526S219600, C526S227000, C526S230500, C526S263000, C526S264000, C526S265000
Reexamination Certificate
active
06300442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to cosmetically or pharmaceutically-acceptable compositions, and, more particularly, to a process of making such compositions in the form of an emulsion or gel.
2. Description of the Prior Art
J. Shih, in U.S. Pat. No. 5,015,708, described a non-aqueous, precipitation polymerization process for making N-vinyl lactam terpolymers in which the polymerization step was carried out in an aliphatic hydrocarbon solvent such as heptane or hexane. The reaction product was a white powder of the terpolymer, however, with undesirable traces of heptane or hexane present therein.
J. Shih, in U.S. Pat. No. 5,156,914, described a process of polymerizing a vinyl monomer and crosslinking agent in an organic solvent such as cyclohexane in the presence of small amounts of a siloxane to provide a white powdery product in which the siloxane was entrapped in a crosslinked polyvinylpyrrolidone matrix.
S. Kopolow, in U.S. Pat. No. 5,130,121, disclosed an aqueous polymerization process for making a N-vinylpyrrolidone polymer encapsulating a silicone oil.
K. Tsubuko et al, in U.S. Pat. No. 5,189,102, described a process for polymerizing vinyl monomers by radical addition in silicone oil solvents, and of isolating the polymerized resin free of silicone oil.
Accordingly, it is desired to provide a process for making a cosmetically or pharmaceutically-acceptable emulsion or gel composition, including vinyl polymers and an oil which functions, both as the solvent during preparation of the polymer and as the oil in the composition.
These and other objects and features of the invention will be made apparent from the following description of the invention.
SUMMARY OF THE INVENTION
A process of making a cosmetically or pharmaceutically-acceptable emulsion or gel composition which comprises: (a) heating a reaction mixture comprising, by weight, about 5-70% of a vinyl monomer in about 30-95% of an oil as solvent, wherein said oil is selected from the group consisting of a silicone oil, a mineral oil and a water-insoluble organic ester and a free radical initiator, optionally in the presence of a crosslinking agent and/or an oil soluble surfactant, with agitation, under an inert gas, at about 40-150° C., wherein the oil is present in an amount sufficient to keep the resultant vinyl polymer in a stirrable state until the end of the polymerization, (b) adding a surfactant, if a suitable surfactant was not present during polymerization, and, (c) then adding water to form an oil-in-water, a water-in-oil or a water-in-oil-in-water emulsion or gel, in a volume ratio of oil-in-water of 30:70 to 10:90, or water-in-oil of 90:10 to 30:70.
DETAILED DESCRIPTION OF THE INVENTION
The unique properties of many oils make it desirable to include them in aqueous-based compositions. For example, cosmetically and pharmaceutically-acceptable materials such as silicone oils, fluids and gums, mineral oils, and water-insoluble organic esters such as isopropyl palmitate and isopropyl myristate, are particularly useful in formulations for the hair and skin. In these compositions, the lubricity and hydrophobicity properties of the oils are beneficial for the user.
In this invention, vinyl polymers useful in cosmetic compositions are prepared in a non-aqueous, heterogeneous polymerization process using an oil as a solvent for the monomer during the polymerization reaction. The oil solvent also acts as a medium to keep the polymer product in a stirrable state throughout the polymerization. The reaction product is a slurry of the vinyl polymer in oil. If desired, the reaction product may be filtered to provide the vinyl polymer as a powder swollen with oil. Thereafter, the reaction product itself, or the polymer powder swollen with oil, is homogenized with water to form a uniform liquid emulsion or gel which is directly useful as the cosmetic or pharmaceutical composition.
Generally about 5-70%, preferably 10-30%, by weight, of the vinyl monomer reactant is used in the process, and about 30-95% of the oil is included for the solvent and medium functions in the process.
Suitable silicone oils or fluids for use in the invention may be selected from non-volatile silicones, such as polyalkyl siloxanes, polyaryl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers; and volatile silicones such as cyclomethicones also may be used.
Non-volatile polyalkylsiloxanes thus include, for example, polydimethylsiloxanes (Dimethicone) with viscosities ranging from about 5 to about 600,000 centistokes (cS) at 25° C. These siloxanes are available, for example, from the General Electric Company as the VISCASIL series and from Dow Corning as the Dow Corning 200 products. Their viscosity can be measured by the glass capillary viscometer procedure set forth in Dow Corning Corporate Test Method CTM 0004 issued Jul. 20, 1970. Preferably, the viscosity of these siloxanes selected have a viscosity of about 100 to about 100,000 cS, and most preferably, a viscosity of up to about 15,000 cS.
Suitable non-volatile polyalkylaryl siloxanes include, for example, poly(methylphenyl) siloxanes having viscosities of about 15 to 65 cS at 25° C. These siloxanes are available, for example, from the General Electric as SF 1075 methylphenyl fluid or from Dow Corning as 556 Cosmetic Grade Fluid. Additionally, poly(dimethylsiloxane)-(diphenylsiloxane) copolymers having a viscosity in the range of about 10 to 100,000 cS at 25° C. are useful.
These and other suitable silicones are disclosed in U.S. Pat. Nos. 2,826,551, 3,964,500 and 4,364,837.
Other suitable oils for use herein include cosmetically or pharmaceutically-acceptable materials such as light and heavy mineral oils, and water-insoluble organic esters such as isopropyl palmitate and isopropyl myristate.
The polymerization process is carried out with a free radical initiator present in the polymerization reaction mixture. The reaction product thus includes the vinyl polymer corresponding to the vinyl monomer or monomers selected. Suitable free radical initiators are diacetyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, t-butyl peroxypivalate, t-butyl peroctoate, t-amyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, di-(4-t-butylcyclohexyl) peroxydicarbonate, 2,2′-azo-bis(isobutyronitrile), 2,2′-azo-bis(2,4-dimethylvaleronitrile), or 1,1′-azo-bis(cyanocyclohexane), and mixtures thereof.
A crosslinked vinyl polymer may be obtained in the process when the optional crosslinking agent is included in the reaction mixture. Suitably, the crosslinking agent is present in an amount of about 0.1-10 wt. %, preferably 0.3-2%, based on the amount of vinyl monomer present. In the presence of such a crosslinking agent, the vinyl monomer will form the corresponding crosslinked vinyl polymer, which, upon homogenization with water, will provide a uniform liquid gel product.
In the practice of the present invention, the oil solvent is charged into a reactor, under agitation, and in a nitrogen atmosphere, and heated to about 40°-150° C., preferably about 65° C. Then the free radical initiator is added. Thereafter the vinyl monomer is added continuously over a period of about 1-12 hours, preferably about 3-6 hours. Preferably, the vinyl monomer and optional crosslinking agent are fed into the reactor at a rate such that substantially no free monomer is present during the polymerization.
After polymerization is complete, the polymer is obtained as a slurry in oil. The slurry can be used as is or filtered to remove excess oil where the product consists of solid polymer with significant amount of absorbed oil. Both slurry and filtered polymer are useful in cosmetic and pharmaceutical formulations.
Suitable vinyl monomers include, but are not limited to, N-vinylamides and N-vinyl lactams, such as N-vinylpyrrolidone, N-vinylcaprolactam; and N-vinylformamide, and optinally with comonomers such as vinyl acetate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, an alkyl (meth)acrylate, an alkyl (meth)acrylamide, a hydroxyalkyl (meth)ac
Chuang Jui-Chang
Plochocka Krystyna
Shih Jenn S.
Davis William J.
ISP Investments Inc.
Katz Walter
Maue Marilyn J.
Zitomer Fred
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