Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-11-08
2001-04-24
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C524S588000, C528S015000, C516S023000, C516S903000, C516S906000
Reexamination Certificate
active
06221979
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
FIELD OF THE INVENTION
This invention is directed to a blend of certain silicone elastomers which can be used to compatibilize organic oils. The blend can also be used to prepare water-in-organic oil emulsions. The organic oils can be as polar as sunflower oil known to have an interfacial tension of about 19.3 mN/m. These benefits cannot be achieved using only one of the silicone elastomers.
For example, it was determined that Vitamin A was not soluble in either one of the silicone elastomers, but that it could be solubilized in a blend of the two silicone elastomers. This provides an improved delivery system for active ingredients such as Vitamin A, which are generally considered to be difficult to solubilize.
If desired, emulsions containing a blend of the silicone elastomers can be used for delivering water soluble active ingredients such as Vitamin C and &agr;-hydroxy acids. In addition, it has been demonstrated that certain linear silicone polyethers can be used in place of one of the silicone elastomers in forming these new blends.
BACKGROUND OF THE INVENTION
A crosslinked elastomeric silicone polyether is disclosed in U.S. Pat. No. 5,811,487 (Sep. 22, 1998). A crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms is disclosed in U.S. Pat. No. 5,880,210 (Mar. 9, 1999). Both of these U.S. patents are assigned to the same assignee as the present invention.
However, neither of the common assignee's patents describe as a new composition of matter, a blend of (i) a crosslinked elastomeric silicone polyether, and (ii) a crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms.
The patents also fail to suggest either a water-in-oil emulsion containing the new composition of matter, or a clear solution containing the new composition of matter.
The patents further fail to suggest as a second new composition of matter, a blend of (i) a linear silicone polyether, and (ii) the crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms. In addition, the patents fail to suggest a water-in-oil emulsion containing the second new composition of matter.
These new and novel concepts are the subject matter of the present invention.
BRIEF SUMMARY OF THE INVENTION
This invention relates to a new composition of matter which is a blend of (i) a crosslinked elastomeric silicone polyether, and (ii) a crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms.
The invention also relates to a water-in-oil emulsion containing this composition of matter. In addition, the invention relates to a clear solution containing the composition.
In an alternate embodiment of the invention, a second new composition of matter is provided, and it is a blend of (i) a linear silicone polyether, and (ii) the crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms.
According to this alternate embodiment, a water-in-oil emulsion can also be formed containing the second new composition of matter.
These and other features of the invention will become apparent from a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
One composition of matter according to the present invention is a blend of (i) a crosslinked elastomeric silicone polyether, and (ii) a crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms.
The crosslinked elastomeric silicone polyether and methods of preparing crosslinked elastomeric silicone polyethers are described in detail in the common assignee's U.S. Pat. No. 5,811,487, incorporated herein by reference.
Generally, such crosslinked elastomeric silicone polyethers are prepared by reacting an ≡Si-H containing polysiloxane (A) and a mono-alkenyl polyether (B) in the presence of a platinum catalyst, until an ≡Si-H containing siloxane with polyether groups (C) is formed. The ≡Si-H containing siloxane with polyether groups (C) is then reacted with an unsaturated hydrocarbon (D) such as an alpha, omega-diene, in the presence of a solvent (E) and a platinum catalyst, until a silicone elastomer is formed by crosslinking and addition of ≡SiH across double bonds in the alpha, omega-diene (D).
The crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms and methods of preparing crosslinked elastomeric silicones containing alkyl groups having 3-40 carbon atoms are described in detail in the common assignee's U.S. Pa. No. 5,880,210, incorporated herein by reference.
Generally, such crosslinked elastomeric silicones containing alkyl groups having 3-40 carbon atoms are prepared by reacting an ≡Si-H containing polysiloxane (A), an alpha-olefin (B), and an alpha, omega-diene (C). The reaction is conducted in the presence of a platinum catalyst, and in the presence of a low molecular weight silicone oil or other solvent (D). The reaction is carried out by grafting long chain alkyl groups from the alpha-olefin (B) onto the ≡Si-H containing polysiloxane (A), and then crosslinking and addition of ≡Si-H in the grafted ≡Si-H containing polysiloxane across double bonds in the alpha, omega-diene (C).
While the crosslinked elastomeric silicone containing alkyl groups may contain alkyl groups having 3-40 carbon atoms, preferably, the crosslinked elastomeric silicone containing alkyl groups should contain alkyl groups having 16-30 carbon atoms.
In preparing blends according to the present invention, the crosslinked elastomeric silicone polyether and the crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms are mixed, i.e., blended, in a weight ratio of from 4:1 to 1:8, preferably 1:1 to 1:4.
Both the crosslinked elastomeric silicone polyether and the crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon atoms constitute polymeric molecules which are crosslinked together to form a gel consisting of a three-dimensional molecular polymeric network containing tens, hundreds, and thousands of crosslinking units between and among the polymeric molecules. Typically, they each contain and are swollen with from 65 to 98 percent by weight of an oil.
Both U.S. Pat. No. 5,811,487 and U.S. Pat. No. 5,880,210 contain extensive lists of appropriate oils which can be used, among which are volatile polydimethylsiloxanes such as octamethyltrisiloxane and decamethylcyclopentasiloxane, nonvolatile polydimethylsiloxanes, aliphatic hydrocarbons such as pentane and heptane, aromatic hydrocarbons such as benzene and toluene, alcohols such as methanol and ethanol, aldehydes such as formaldehyde, ketones such as acetone and methyl ethyl ketone, amines such as methylamine, esters such as ethyl acetate, ethers such as tetrahydrofuran, glycols such as glycerol, glycol ethers such as ethylene glycol monomethylether, alkyl halides such as chloroform and carbon tetrachloride, aromatic halides such as chlorobenzene, flavoring agents such as peppermint oil, and fragrances such as musk and myrrh.
One particularly suitable use of the mixture of the crosslinked elastomeric silicone polyether and the crosslinked elastomeric silicone containing alkyl groups having 3-40 carbon, is for the preparation of water-in-oil emulsions consisting of an aqueous disperse phase and an oil continuous phase. In that application, the aqueous phase may contain a water soluble active ingredient, and the oil phase may contain an oil or an oil soluble active ingredient.
The water soluble active ingredient for the aqueous phase of the water-in-oil emulsion can be, for example, (i) a water soluble Vitamin, (ii) a water soluble drug, or (ii) an &agr;-hydroxy acid such as glycolic acid, lactic acid, tartaric acid, and citric acid, i.e., fruit acids. In this latter instance, significant benefits can be realized as fruit acids
Lin Zuchen
Schulz, Jr. William James
Smith Janet Mary
Cesare James L. De
Dawson Robert
Dow Corning Corporation
Zimmer Marc S.
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