Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2000-03-23
2002-05-07
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S063000, C424S078020, C424S078030
Reexamination Certificate
active
06383502
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to coating compositions and compositions to be used as additives. More specifically, this invention relates to siloxy-polymer containing compositions in a solvent, wherein the composition does not sting on application to the skin of a user.
BACKGROUND
Coating compositions are desired in the art, both as skin protecting compositions and medicament containing compositions.
U.S. Pat. Nos. 5,103,812 and 4,987,893 relate to a conformable bandage and coating materials. These materials are combinations of alkylsiloxy silicone containing polymers admixed with liquid polydimethylsiloxanes. Polymers of these compositions are incorporated into a solvent system that is preferably polydimethylsiloxane having the solubility parameter of 6.8-7.2 [cal/cm
3
]
½
. See column 5, lines 50-55. These polymer films are also said to be able to be cast from liquids containing good solvents with solubility parameters of between about 9 to 10 [cal/cm
3
]
½
. Specific examples of such solvents are tetrahydrofuran and ethylacetate. See column 6, lines 50-54.
SUMMARY OF THE INVENTION
A composition for application to the skin, comprising: 1-40% siloxane containing polymer; 60-99% of an Alkane-Based Siloxy Polymer Reaction Solvent, and 0-15% of adjuvants is provided.
A method of making a siloxane-containing polymer is also provided comprising vinyl containing alkylsiloxysilanes alone or as co-, ter- or multi component polymers including other polymerizable monomers, which method comprises undertaking the polymerization in an alkane solvent selected from the group consisting of C
5
—O—
5
—C
9
straight, branched or cyclic alkanes so that the reaction provides a composition having a polymer content greater than 15% by weight.
Aqueous gel compositions are also provided.
DETAILED DESCRIPTION OF THE INVENTION
No-sting skin protectants are described in U.S. Pat. Nos. 5,103,812 and 4,987,893, but these materials cannot be provided at higher solids than 15% without becoming very stringy and pituitous. At higher solids content, the polymer will not spread when painted onto the skin from the described formulation. Furthermore, the method for applying thick coatings to the skin as described in the prior art is through multiple applications of thin coatings. In the prior art method, towelette wipes having solutions comprising 10% polymer content are applied over areas to be treated and dried. By the time the coating is dry on the skin, the applicator wipe may be also dry and a new wipe must be used.
Surprisingly, it has been found that non-stinging coating compositions may be provided utilizing a siloxy polymer, but which is cast from a solvent not previously thought to be appropriate for such use. Optionally, the polymer content of the inventive compositions may be significantly higher than the polymer content possible in prior art compositions, while maintaining good handleability properties.
More specifically, the solvent system for the compositions of the present invention is selected such that it is an Alkane-Based Siloxy Polymer Reaction Solvent. An Alkane-Based Siloxy Polymer Reaction Solvent is a solvent system that primarily contains straight, branched or cyclic alkanes, and is capable of acting as the reaction solvent (i.e. the non-reactive fluid portion of a reaction composition) for the polymerization reaction of the specific monomer composition of TRIS/Methyl Methacrylate/2-Ethylhexyl acrylate in a 53/39/8 weight ratio. The solvent system is readily identified in a routine evaluation by undertaking a polymerization reaction using the specific monomer composition described above under a Standard Polymerization Reaction as defined below.
A Standard Polymerization Reaction comprises reacting 20% total monomer concentration by weight based on monomer plus solvent with VAZO 67 free radical initiator used at 0.3% by weight based on total monomer at a reaction temperature of 70° C. under nitrogen for 36 hours (or less time if greater than 90% monomer conversion has occurred). A solvent system is deemed to be an Alkane-Based Siloxy Polymer Reaction Solvent if, after cooling to room temperature, the reacted composition yields a clear, pourable solution of polymer, and the inherent viscosity (“IV” as tested by ASTM D2857-95 at 25° C. and according to principles discussed in Experiments in Polymer Science, by Edward A. Collins, Jan Bares and Fred W. Billmeyer, New York, Wiley (1973) pp 146-153.) of the polymer product is measured in ethyl acetate solvent at a nominal solids concentration of 0.5% (w/v)is less than 0.5 dl/g. Solvents which yield polymer with inherent viscosity greater than 0.5 dl/g are unsuitable.
A specific procedure for the test is detailed below.
A mixture of 4.24 g TRIS, 3.12g methyl methacrylate and 0.64g 2-ethyl hexyl acrylate is dissolved in 32 g of solvent in a 4 oz narrow mouth flint glass bottle and 0.024 g of VAZO 67 is added. The solution is purged with nitrogen at a flow rate of 1 liter/ minute for two minutes to remove dissolved oxygen. The bottle is closed tightly with a teflon lined metal cap and placed in a launder-o-meter preset at 70° C. for at least 24 hours. Conversion is determined from measurement of percent non volatile solids by loss on drying at 105° C. for 60 minutes.
Preferred solvents of the present invention are selected from one or more C
5
-C
12
straight, branched, or cyclic alkanes. Particularly preferred solvents are methylcyclopentane; n-heptane; n-octane; n-nonane; 2,2,4-trimethyl pentane; 3,4-dimethyl hexane. The solvent system may also comprise a blend of solvents that are a mixture of straight, branched or cyclic C10-C12 alkanes with one or more C
5
-C
9
straight, branched or cyclic alkanes.
For example, preferred solvent blends include mixtures of one or more of n-decane, n-undecane or n-dodecane with one or more of methylcyclopentane; n-heptane; n-octane; n-nonane; 2,2,4-trimethyl pentane; 3,4-dimethyl hexane.
The present inventive compositions are preferably provided as a skin protecting conformable bandage that is painted on. Alternatively, the compositions of the present invention may be provided as a component in a cosmetic or medicament containing composition.
The liquid polymer-containing coating materials of this invention comprise a siloxane containing polymer and a solvent system which is non-stinging to a user. Preferably the polymer is present from 1 to 40% by weight and the solvent is present in amounts of 60 to 99%. The material forms a coating or bandage in the form of a dried film when applied to a surface or the skin of a user.
Advantageously, the present invention provides the ability to manufacture the polymer in the same solvent as used in the final formulation. It has been found that it is exceedingly difficult to manufacture this polymer in the prior art solvent system hexamethyl disiloxane (“HMDS”). The ability to manufacture in the same solvent as the ultimate product is a significant advantage in cost savings, and additionally provides a more complete distribution of reaction products that may aid in film formation.
Use of the solvent system of the present invention allows for incorporation of higher solids content of the polymer, and also allows for selection of the polymer formulation to provide suitable materials for the desired use at lower siloxy silane component content.
It has surprisingly been found that the alkane solvents as described herein may be highly effective cosolvents with volatile siloxane (such as HMDS), which can substantially increase the amount of solids content that may be obtained without becoming pituitous. Additionally, it has been found that the addition of about 5%-10% of Tea Tree Oil (oil of Melaleuca alternifolia) and the like similarly increases the amount of solids content that may be obtained without becoming pituitous.
Preferably, the siloxane containing polymer comprises at least one vinyl containing alkylsiloxysilane and an addition polymerizable comonomer.
It is a feature of the invention that the liquid materials can ac
Dunshee Wayne K.
Eian Gilbert L.
3M Innovative Properties Company
Di Nola-Baron Liliana
Gwin Doreen S. L.
Page Thurman K.
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