NON-AQUEOUS EMULSION OF SILICONE OIL AND STEARINE

Abstract: A non-aqueous emulsion comprises a stearine, a silicone, and, optionally, a diluent such as a glyceride, and a silicone emulsifier. The stearine is present in an amount sufficient to provide a non-aqueous emulsion when the components are melted together and mixed until the emulsion is set. The silicone oil is preferably a dimethyl silicone which can be optionally endblocked while the preferred stearine comprises hydrogenated rapeseed stearine or hydrogenated castor stearine. The non-aqueous emulsion can be employed as a lubricant for natural or synthetic fibers. In addition, the non-aqueous emulsion can be employed within a cream or ointment composition with at least one active ingredient.

Description: NON-AQUEOUS EMULSION OF SILICONE OIL AND STEARINE BACKGROUND OF THE INVENTION The present invention relates to non-aqueous emulsions. The use of certain non-aqueous emulsions as a lubricating composition is known in the art. For example, U.S. Patent No. 4,125,470 to Fenton et al relates to a band-ply lubricant concentrate which comprises an alkylene oxide polymer, a particular siloxane copolymer dispersing agent, a polydimethyl- siloxane fluid and, optionally, mica or talc. U.S. Patent No. 4,253,981 to Ayres relates to a lubricating composition for which comprises a diisopropyl adipate, certain octanoic acid esters, a silicone oil and a surfactant. However, the need still exists for a topical lubricant which can be effectively employed with fibers such as spandex, polyester, acrylic and sewing threads. Accordingly, it is an object of the present invention to provide a stable non-aqueous oil-in-oil emulsion. It is a further object to provide a non-aqueous emulsion which has a thixotropic rheology and which can be effectively employed as a topical lubricant for fibers such as spandex and sewing threads. These and further objects will become apparent from the specification and claims that follow. SUMMARY OF THE INVENTION In accordance- with the foregoing objectives, the present invention relates to a non-aqueous emulsion which is useful as a topical lubricant. The oil-in-oil emulsion according to the present invention is composed of a stearine, a silicone and, optionally, a diluent such as a glyceride, and a silicone emulsifier. The stearine is present in an amount which is sufficient to provide a non-aqueous emulsion when the components are melted together and mixed until the emulsion is set. The silicone oil is preferably a dimethylsilicone which can be optionally endblocked with trimethyl siloxy groups, alkyl groups and aryloxy groups. In another aspect, the present invention relates to a lubricant for fibers or threads comprising the above- described non-aqueous emulsion. The present invention also relates to a fiber composition comprising a fiber and the lubricant. In still another aspect, the present invention relates to a cream or ointment composition comprising the non-aqueous emulsion and at least one active ingredient. DETAILED DESCRIPTION OF THE EMBODIMENTS The silicone oil employed within the present invention include dimethylsilicones which can be optionally endblocked with trimethyl siloxy groups, alkyoxy groups from C^-CS Q , and aryloxy groups. The preferred silicone oils are trimethylsilox endblocked dimethylsilicones, although silicones terminated with silanol endgroups may also be used. Other silicone compositions such as dialkylsilicones, diarylsilicones, alkylarylsilicones, and alkenylalkylsilicones may also be employed in the present invention. In addition, the silicone may be the aforementioned compositions which contain silicon mers having at least one substituent. For example, the silicone composition may contain silicon mers with a alkylpoly(oxyalkylene) substituent. In other instances the silicone may be the aforementioned compositions which contain silicon mers with an aminoethyl, an aminopropyl, or an aminoethyl-aminopropyl substituent. In a more preferred embodiment, the silicone comprises a trimethylsiloxy endblocked dimethylsilicones with viscosities in the range of 10 centistokes to 500 centistokes. Diluent fluids such as glycerides, hydrocarbons, esters, and alkoxylates may be employed in concentrations up to about 95%, although concentrations of about 25% are preferred for most applications. Examples of glycerides which can be employed in the present invention include canola (low erucic acid rapeseed oil) , rapeseed oil (high erucic acid rapeseed oil), soybean oil, jojoba oil, castor oil, cottonseed oil, coconut oil, palm kernel oil, palm oil, sunflower oil (low and high-oleic varieties) , fish oils (e.g. orange roughy oil) , fractionated palm kernel oil and soybean oils. The stearines which can be employed within the present invention include those stearines having a high melting point, i.e., above about 50°C (122°F). These stearines (i.e., fully hydrogenated oils) can include soybean, cottonseed, rapeseed, palm, and castor stearine or mixtures thereof. In addition to the hydrogenated oils, high melting waxes such as carnauba or candellia may be employed. Hydrogenated rapeseed stearine or hydrogenated- castor stearine are particularly preferred due to their great stability and ease of use. The amount of stearine employed within the present invention is that amount which is effective in providing the formation of a thixotropic non-aqueous emulsion when the components are melted and mixed together until set. In particular, the amount of stearine present allows for the creation of an emulsion which is extremely stable, i.e., very difficult to breakdown by known means. For example, the emulsion can remain stable even though surfactants may be added in amounts which would breakdown most emulsions. Preferably, the amount of stearine employed is less than about 40% by weight, with about 1 to about 5% by weight being more preferred. A silicone emulsifier (or surfactant) is optionally added to the emulsion in order to alter the viscosity of the mixture and/or increase the stability of the emulsion. The preferred silicone emulsifiers are orga o-modi f i ed silicones that contain polyalkyleneoxide groups. An example of a commercially available emulsifier is SIL ET 7001, manufactured by. Union Carbide. Although a wide concentration range for the silicone emulsifiers (i.e., any amount which does not prevent the emulsion from forming) may be used, concentrations of about 0.25% to about 3% by weight are preferred. The non-aqueous emulsion according to the present invention can be made by conventional processes. For example, in one embodiment at least part of the silicone oil(s) to be employed is heated together with the desired stearine until melted. These components are then mixed together in an homogenizer and the remaining portion (if any) of the silicone oil is added. This final mixture is then mixed within conventional apparatus such as a homogenizer (e.g., a tissue mixer) until the emulsion is set. In an alternative method of making the emulsion according to the present invention, a solid stearine can be mixed with a silicone fluid and size reduction can be effected by any mechanical means known in the art such as a Wearing blender. In another method, a first non-aqueous emulsion of a stearine in a first silicone oil can be prepared by a conventional method as described above. In a similar fashion, a second non-aqueous emulsion of a stearine within a diluent fluid such as a glyceride is produced. The first and the second emulsions are then mixed together in order to form the final non-aqueous emulsion. In another method, the silicone fluid, silicone emulsifier, and the stearine such as hydrogenated castor stearine are heated together and gently stirred while cooling. During the process of cooling, a stable emulsion forms. Depending on the emulsion composition, a thixotropic emulsion may be formed using the aforementioned techniques. Because of thixotropic rheology, these emulsions can be employed as topical lubricants for a variety of applications, e.g., lubricants for fibers. Advantages of this lubricant according to the present invention include: improved fiber-to-fiber cohesion during processing, and in the case of spandex fibers, reduced swelling and lubricant absorption because of very high viscosity at low shear conditions. In particular, these compositions may be as lubricants on synthetic fibers such as spandex, polyester, nylon, polymethane, polybenzimidazole, polypropylene, acrylic, aramid, and polyethylene. In addition to the synthetic fibers, the composition may be applied to proteinaceous fibers such as silk or wool as well as natural or synthetic cellulosic fibers such as cotton or rayon. The composition may be applied by any means recognized in the art, for example, kiss rolls or capillary metering systems. Further, these compositions may be used on other fibrous assemblies such as sewing thread and textured filament yarns. For example, in the past, lubrication of sewing thread has often been achieved by applying a molten lubricant composed of paraffin wax, esters such as glycerol monostearate, and * a dimethyl-silicone, often with a viscosity in the range of 100 cst-1000 cst. These "hot melt" lubricant compositions have several limitations. Only limited organic components, such as certain waxes and esters, may be incorporated into the formulation because of poor solubility in the silicone phase. In addition, these previous compositions must be applied in a molten condition at 80 C-120 C since the organic components are solids at lower temperatures and insoluble in the silicone phase at lower temperatures. In contrast, the compositions of the present invention are liquids at a wide range of temperature and, thus, may be applied at ambient temperatures. A further advantage of the present invention is that high concentrations of organic components such as glycerides may be readily incorporated. These compositions can also be employed in numerous applications beyond those in the fiber and textiles industry. For example, the absence of water and a broad temperature range in which viscosity is relatively constant indicates utility in other lubricant applications such as gasket and seal lubrication. In addition, these compositions may be used in skin care compositions, with or without additional emollients, because their thixotropic nature imparts a desirable soft aesthetic when applied to the skin. Accordingly, the composition of the present invention can be employed within cleansing creams, emollient creams, hand creams, and as bases for sun screening preparations. Unlike conventional compositions based on aqueous emulsions, the non-aqueous emulsions of the present invention do not contain bactericides. Furthermore, they are anticipated to have hypoallergenic properties. Because no water is present, the compositions of the present invention may be extremely desirable as ointments and creams for wound care. The reason for this is that the water which is employed within conventional creams and ointments forms an ideal medium for bacterial growth during storage in containers as well as in the septic regions of wounds. The formulations based on the present invention can also be employed in preparations used as sunscreening preparations. The currently known preparations have limited durability in use because they are removed by perspiration and contact with water as the result of swimming, etc. In addition, because of the high viscosity embodied by compositions of the present invention as well as their affinity for skin, ' they can be employed within insect repellant preparations which have exceptionally long lasting efficacy. In order to further illustrate the present invention, and the advantages thereof, the following specific examples are given. ϊt being understood that same are intended solely as illustrative and in nowise limitative. EXAMPLES Example 1. Rapeseed stearine (2 grams) and L-45-10 silicone oil (98 grams) are weighed into a beaker. The mixture is heated in a microwave oven until the stearine melts. The mixture is then stirred intermittently with a tissue homogenizer until the stearine crystallizes (texture is thick and smooth, like shortening) . Example 2, Rapeseed stearine (2 grams) , Silwet L- 7001 silicone surfactant (0.25 grams) were weighed together into a beaker and melted over a flame. Approximately 50 grams of L-45-10 silicone oil was added to the melt and the mixture stirred with a tissue homogenizer. When the mixture began to set the remaining silicone oil (q.s. to 100 gram total weight of all reactants) was added and mixed until the stearine crystallized. Example 3, Refined, bleached, filtered canola oil (394 grams) and rapeseed stearine (8 grams) were mixed, heated until melted, and then blended with a tissue homogenizer until set (i.e. , .crystallized). This mixture comprises Part A of this method. In Part B, 250 grams L-45-500, 150 grams L-45-100 and rapeseed stearine (8 grams) were mixed, melted, and stirred with the tissue homogenizer until set. Into a beaker, Part A (20 grams) and Part B (80 grams) were combined with stirring until homogeneous. Alternative compositions employing this method can encompass various ratios of Part A to Part B, including: 40% A:60% B; 60% A:40% B; 80% A:20% B. Example 4. Hydrogenated castor stearine (25 grams), Silwet silicone surfactant (one gram) , and L-45-500 silicone fluid (74 grams) were heated to 100 degrees C. The mixture was gently stirred until set. While the present invention has been described in terms of various preferred embodiments, a skilled artisan will appreciate the various modifications, substitutes, omissions and changes that may be made without departing from the spirit thereof. Accordingly, it is intended that the scope of the present invention be limited solely by the scope of the following claims, including equivalents thereof.

Claims: CLAIMS : 1. A non-aqueous emulsion comprising: ( a ) at least one silicone oil; and (b) at least one stearine which is present in an amount sufficient to provide for a non-aqueous emulsion of the stearine in the silicone oil when (a) and (b) are melted together and mixed. 2. A non-aqueous emulsion according to claim 1 further comprising (c) a silicone emulsifier. 3. A non-aqueous emulsion according to claim 2 wherein the silicone emulsifier is present in an amount of about 0.25% to about 3% by weight of the emulsion. 4. A non-aqueous emulsion according to claim 2 further comprising (d) a diluent fluid comprising at least one of a glyceride, hydrocarbon, ester and alkoxylate. 5. A non-aqueous emulsion according to claim 1 further comprising (c) a diluent fluid comprising at least one of a glyceride, hydrocarbon, ester and alkoxylate. 6. A non-aqueous emulsion according to claim 4 wherein the diluent is present in an amount greater than 0 but less than about 95% by weight of the emulsion. 7. A non-aqueous emulsion according to claim 1 wherein said at least one silicone oil comprises at least one dimethyl silicone. 8. A non-aqueous emulsion according to claim 1 wherein said at least one silicone oil comprises dialkenylsilicones, dialkylsilicones, diaryl silicones, alkylarylsilicones, alkenylalkylsilicones, or mixtures thereof. 9. A non-aqueous emulsion according to claim 1 wherein said at least one stearine comprises at least one stearine having a melting point above about 50°C. 10. A non-aqueous emulsion according to claim 1 wherein said at least one stearine comprises hydrogenated rapeseed stearine or hydrogenated castor stearine. 11. A non-aqueous emulsion according to claim 1 wherein the stearine is present in an amount greater than 0 but less than about 40% by weight of the emulsion. 12. A non-aqueous emulsion according to claim 1 wherein the stearine is present in a amount of about 1 to about 5% by weight. 13. A non-aqueous emulsion according to claim 2 wherein said sil icone emulsifier comprises an organomodified silicone containing polyalkyleneoxide groups . 14. A lubricant for fibers or thread comprising a non-aqueous emulsion which comprises: (a) at least one silicone oil; (b) at least one stearine which is present in an amount sufficient to provide a non-aqueous emulsion of the stearine in the silicone oil upon melting and mixing of (a) and (b) . 15. A lubricant according to claim 14 further comprising (c) a silicone emulsifier. 16. A lubricant according to claim 14 wherein said at least one silicone oil comprises dimethyl silicone. 17. A lubricant according to claim 14 wherein said at least one silicone oil comprises dialkenylsilicones, dialkyl silicones, diaryl silicones, alkylaryl silicones, alkenylalkyl silicones or mixtures thereof. 18. A lubricant according to claim 15 wherein said at least one silicone oil comprises dialkenylsilicones, dialkyl silicones, diaryl silicones, alkylaryl silicones, alkenylalkyl silicones or mixtures thereof. 19. A lubricant according to claim 15 wherein said stearine comprises hydrogenated rapeseed stearine or hydrogenated castor stearine. 20. A lubricant according to claim 15 wherein said stearine comprises hydrogenated rapeseed stearine or hydrogenated castor stearine. 21. A lubricant according to claim 14 wherein the stearine is present in an amount of greater than 0 but less than 40% by weight. 22. A lubricant according to claim 15 wherein said silicone emulsifier comprises an organomodified silicone containing polyalkyeneoxide groups. 23. A composition which can be employed as a cream or ointment comprising the non-aqueous emulsion according to claim 1 and at least one active ingredient. 24. The composition according to claim 23 wherein the at least one active ingredient comprises a cleansing agent, an emollient, a skin moisturizing agent, a sunscreen active agent, an insect repellent, a pharmaceutically active agent, or mixtures thereof. 25. A fiber composition comprising a fiber and a lubricant wherein the lubricant is a lubricant according to claim 14. 26. The composition according to claim 25 wherein the fiber comprises a synthetic fiber, a proteinaceous fiber, or a natural cellulosic fiber. 27. The composition according to claim 26 wherein the synthetic fiber comprises polyester, nylon, polyurethane, polybenzylmidozole, polypropylene, acrylic, aramid, polyethylene, synthetic cellulosic fiber, or mixtures thereof. 28. The composition according to claim 26 wherein the proteinaceous fiber comprise silk or wool. 29. The composition according to claim 27 wherein the synthetic cellulosic fiber comprises rayon. 30. The composition according to claim 26 wherein the natural cellulosic fiber comprises cotton.

Inventors: GREENE GEORGE H, PHILLIPS JAMES C, STULTS JERRY F, GREENE, GEORGE, H., PHILLIPS, JAMES, C., STULTS, JERRY, F.
Applicants: GREENE GEORGE H, PHILLIPS JAMES C, STULTS JERRY F, GREENE, GEORGE, H., PHILLIPS, JAMES, C., STULTS, JERRY, F.
Application year: 1991
Main classification: C10M129
IPC codes: D06M13, D06M15