GB2079300A

GB2079300A - >Transparent Silicone Emulsions

Info

Publication number: GB2079300A
Application number: GB8118131A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1980-07-01
Filing date: 1981-06-12
Publication date: 1982-01-20
Also published as: GB2079300B; IT8122654A0; ES8300469A1; BE889448A; CA1211595A; IT1137267B; DE3125333A1; JPS6359422B2; NL8103129A; ES503601A0; FR2485923A1; JPS5744656A

Abstract

Optically clear silicone emulsions can be obtained from non-transparent emulsions comprising linear polysiloxane oils or volatile cyclic polysiloxanes dispersed in water using an emulsifier by adding effective amounts of an optical index adjusting agent selected from water soluble polyols and polyethers. These transparent silicone emulsions can be further combined with cosmetic or medicinal agents as desired.

Description

SPECIFICATION Transparent Silicone Emulsions The present invention provides a system for emulsifying cyclic and linear polysiloxane oils to yield transparent base products which can be readily formulated into cosmetic and medicinal products.

Potential uses for transparent water based silicone emulsions include deodorants, antiperspirants, skin care products, hair care products, mold releases and antiblocking agents, textile softeners, etc.

The process of the present invention can be utilized to provide clear silicone emulsions when such emulsions are first prepared by conventional silicone emulsion technology. These conventional emulsions ordinarily have a milky or cloudy appearance which is unsuitable for many cosmetic applications. The present process can also be utilized to provide transparent emulsions when such emulsions are prepared from volatile cyclic siloxanes as taught in the parent application. Such volatile silicone emulsions provide particularly useful cosmetic and medicinal products and the added property of transparency enlarges their usefulness.

Prior art transparent emulsions have heretofore been unable to utilize advantageous silicone technology. They had been prepared, where possible, as microemulsions made up of very small colloid particles which would be emulsified in approximately 30% mineral oil, 30% emulsifying agent and 40% water. While the micro particles may provide a measure of transparency, such micro-emulsions are inherently unsatisfactory since they require unduly large amounts of the emulsifying agents in order to provide a stable product.

The silicone-water emulsion compositions of the present invention are particularly well-suited for serving as a vehicle for the application of epidermal enhancing agents. The expression "epidermal enhancing agents" refers to those compositions having properties generally considered as being beneficial when applied to portions of the body. For example, such agents include a wide range of cosmetics and medical and pharmaceutical compounds.

In the cosmetic category there are many types of products which can be beneficially applied to the skin in a silicone emulsion form. For example, such cosmetics would include cream eye shadows, foundations, blushes, lip gloss, mascara and eyeliner, cover-up-type compositions and wrinkle creams, moisturizers, acne cover-up, depilatories and cuticle removers, etc.

Such emulsions can also be used for cleansing purposes and may take the form of shampoos, soaps, conditioners and moisturizers. Additionally, hair dyes may be applied in a silicone-water emulsion vehicle.

Additional cosmetic uses include the application of perfumes, colognes and sachets to the body.

Among the particularly useful applications would be deodorants and antiperspirants.

Among the many medical uses of such an emulsion vehicle would be first aid uses such as burn ointments and the application of antiseptics. Furthermore, corn, wart and callous removing agents, for example, can be successfully applied to the skin in such a silicone-water emulsion vehicle.

Of course, the consistency of the silicone-water emulsion of the present invention can be varied through many degrees from a lotion-like consistency through cold cream-like pastes up to gel-type ointments or salves on the order of a petroleum jelly.

The fact that these emulsions can now be prepared in transparent form adds a measure of commerciability to cosmetic products. For cosmetic use a clear vehicle is ordinarily preferred over heretofore available cloudy emulsions.

Silicones are synthetic polymers ordinarily commercially prepared from chlorosilane monomers and available in the form of fluids, resins and rubber gums. Of particular interest to the cosmetic industry are those polymers formulated into emulsions, greases, pastes, etc. In these formulations a wide variety of materials may be used in conjunction with the silicones.

Monomeric chlorosilanes are very reactive volatile materials which readily react with moisture to form silicones and byproduct hydrochloric acid. Thus, in the presence of moisture they are considered corrosive materials and may have hazardous properties and must be handled with care. However, after processing into silicone polymers these materials become bland and inert substances. Silicones may be further formulated with other materials to produce various end use compositions and often the physiological effect of the finished composition is determined by the nature of the non-silicone component.

The toxocological properties of silicones have been widely studied and, as a group, polymeric silicone fluids and resins ordinarily have a very low order of toxicity. Considered from a practical viewpoint, the hazards they present are exceedingly minor. Silicone fluid polymers have been the subject ofskin irritation and sensitization patch test studies and are typically shown to be safe. The low level of toxicity of silicone materials has even lead to the acceptance and successful use of silicone fluids in medical and dental applications.

Silicone fluids generally provide excellent protection against water-borne irritants such as harsh detergents and other household cleaning specialties. The chemical inertness and excellent waterrepellency of silicone fluids are the major reasons for their effectiveness in preventing dermatitis.

Silicones may also function as emollients, and provide a pleasant non-stick "feel". Superior suntan lotions and creams can be prepared using silicones, since the silicone fluid is a carrier for the sunscreening agent and resists wash-off by either bathing or perspiration.

Emulsions containing volatile silicone cyclic polysiloxanes have been previously formulated by utilizing emulsifying agents such as dodecyl benzene sulfonic acid, however, these systems require milling or homogenization in order to emulsify the immiscible phases. It is possible to emulsify preparations of this type having only up to about 55% concentration of volatile cyclics and emulsions of this type are frequently utilized to carry out emulsion-type polymerization of cyclic such as octamethyltetrasiloxane.

The parent application provides a method which makes it possible to emulsify iarger concentrations of cyclic polysiloxanes while at the same time eliminating the necessity of milling or homogenization. Furthermore, it provides stable emulsions of cyclic polysiloxanes such that these emulsions do not ordinarily "break" under normal storage and use conditions even when the concentration of volatile cyclic polysiloxane is 80% or more. Additionally, the present invention provides methods for making such emulsions transparent. These are particularly useful properties for consumer oriented products since the emulsions can ideally be utilized as vehicles for conveying epidermal enhancing agents onto the skin of a user in a beneficial manner.

Furthermore, the present invention offers a system for emulsifying volatile cyclic polysiloxanes which yield transparent materials, which can be readily formulated into many consumer products such as antiperspirants and deodorants, etc. Other potential uses for transparent water based cyclic emulsions are skin care products such as hand lotions, skin fresheners, hair preparations and other grooming aids. As noted above, the method of the present invention provides a means for selectively varying the consistency of these emulsions depending upon the ultimate purposes of the product.

An additional advantage resides in the fact that these transparent silicone-water emulsions can be comprised of relatively volatile cyclic polysiloxane constituents such that an emulsion vehicle base will eventually evaporate from the skin and only the beneficial epidermal enhancing agent will be left thereon.

Our prior published British Patent Application No. 2064363 claims a silicone-water emulsion comprising: (A) 100 parts by weight of a cyclic polysiloxane, or a combination of such cyclic polysiloxanes, having the formula,

wherein n is an integer from 3 to 10, R is -CH3,(CH2)zCH3,CH2CH2CF3,CH=CH 2,or -C6H5, andzisanintegerfrom 1 to 10; (B) from 0.7 to 666 parts by weight of an emulsifier; and (C) from 5.0 to 960 parts by weight of water.

Our prior Application also claims a method for producing these emulsions which comprises mixing the cyclic polysiloxane, the emulsifier and the water, and stirring with moderate heat until an emulsion having the desired consistency is produced.

With our present Application, unlike our prior Application, many of the above-described advantages can now be shown by transparent emulsions prepared from linear polysiloxane base materials.

The present invention provides a method of formulating an optically clear silicone emulsion which comprises: (a) forming a non-transparent silicone oil and water emulsion by combining a discontinuous phase of polydiorganosiloxane oil, with a continuous phase of water, and an emulsifying agent or mixture of emulsifying agents; and (b) adjusting the optical clarity of the non-transparent emulsion by combining it with an optical index adjusting agent which is a water soluble polyol or polyether in an amount to render the non-transparent emulsion optically clear.

The optical adjusting agent which will render these silicone water emulsions transparent is conveniently a water soluble polyol or polyether or mixture of these materials. Particularly preferred optical adjusting agents can be selected from the group consisting of glycerin, sorbitol, polyalkylene glycol, polyoxyalkylene derivatives of propylene glycol, alkoxylated organic acids and esters, methoxypolyethylene glycol. For the purposes of the present invention the water soluble polyol optical adjusting agents will also be intended to include amino-functional polyether block polymers and polyethoxylated quaternary ammonium chlorides-ethoxy. Other suitable optical adjusting agents include polydiorganosiloxanes which have been further copolymerized with any of the above described polyols.

The non-transparent silicone oil and water emulsions (A) described above can be made from known techniques utilizing linear polydiorganosiloxane oils such as polydimethylsiloxane. These nontransparent emulsions can also be made according to the techniques of the parent application utilizing volatile cyclic polydiorganosiloxanes as the base silicone oil. After the basic non-transparent silicone water emulsions have been prepared the processes of the present invention can allow a formulator to produce stable optically clear or transparent emulsions by combining the non-transparent emulsions with the effective amounts of the polyol type optical adjusting agent.

To demonstrate the wide spread applicability of the present invention to silicone emulsion technology, it is intended that the process of the present invention can produce optically clear silicone emulsions from non-transparent silicone emulsions which have been prepared as described above and which utilize non-ionic, anionic or cationic emulsifying agents. Suitable nonionic emulsifiers are included in the group consisting of ethyloxalated fatty acids, sorbitan esters, ethoxylated sorbitan esters, ethoxylated ethers, and ethoxylated alkylphenols. Suitable anionic emulsifiers can be selected from the group consisting of alkylbenzene sulfonic acids, salts of alkylbenzene sulfonates, salts of alkyl sulfates, and salts of alkyl or alkylaryl ethoxylated sulfates.Specific examples of these anionic emulsifiers include dodecylbenzene sulfonic acid, sodium lauryl sulfate, and Polystep B-1 and B-10.

Suitable cationic emulsifiers can be selected from the group consisting of quaternary ammonium chlorides and polyethoxylated quaternary ammonium salts. Particular examples of these emulsifiers include Arquad C-50, Arquad 2 S-75, Ethoquad C-25, and Ethoquad 0-25.

The composition of the present invention can further comprise such optically clear silicone emulsions having therein epidermal enhancing agents for cosmetic and medical use.

The above described silicone water emulsion compositions are provided by the process of the present invention wherein a non-transparent silicone oil and water emulsion is first prepared by an emulsification step utilizing the above-described emulsifiers with well known emulsification techniques such as blending or homogenization, whereupon the optical clarity of the non-transparent emulsion can be adjusted to provide an optically clear emulsion by combining the non-transparent emulsion with effective amounts of optical adjusting agents. These optical adjusting agents can be, for example, titrated into the non-transparent silicone emulsion until it becomes apparent that an optically clear emulsion has been obtained. It is also possible, however, to premix the optical agent into the composition in order to prepare an optically clear silicone emulsion final product.

Stable transparent silicone and water emulsions suitable for cosmetic or medicinal use can be provided by the present invention by starting with non-transparent emulsions prepared from either linear or cyclic polysiloxane fluids or oils.

Non-transparent silicone emulsions can be prepared from cyclic polysiloxane starting materials according to the processes of the parent application.

The emulsion starting material can be comprised of 10 parts by weight of a cyclic polysiloxane or a combination of cyclic polysiloxanes having a general formula,

wherein n is an integer from 3 to 10, R is -CH3, -(CH2)2, CH3, CH2CH2CF3,-C H2=CH2, or --C,H, or combinations thereof. The polysiloxanes designated by this formula are known as volatile silicone cyclics and this property of volatility imparts advantageous properties to the emulsion composition.

Particularly useful volatile silicone cyclics are octamethyltetrasiloxane and decamethylpentasiloxane.

The volatile cyclic polysiloxane is combined with an emulsifying agent and water to form a silicone-water emulsion. The order of mixing the ingredients is not critical, however, particularly satisfactory results can be obtained when the emulsifying agents and the water are mixed together in a preblend to which the volatile cyclics are added.

Preferably, the cyclic polysiloxane is added to a preblend consisting of approximately, 50 to 200 parts by weight of water, which is mixed with 100 parts by weight of one or more emulsifying agents and heated until a uniform blend is achieved.

This preblend is suitable for producing a paste-like silicone-water emulsion, however, if a more liquidous or lotion-like consistency is desired, there may range up to 2,000 or more parts water per 1 00 parts of the emulsifying agents. The emulsifying agents may be nonionic, anionic, cationic or amphoteric but of particular importance are those classes of nonionic emulsifiers which are highly ethoxylated. The ethoxylated fatty acids, ethoxylated and non-ethoxylated sorbitan esters, ethoxylated alkyl phenols, and ethoxylated ethers provide the best results for producing emulsions of volatile silicones.

Examples of emulsifiers which may be used to formulate the silicone-water emulsions of the present invention are included in but not limited by the following list: 1) ethoxylated fatty acids such as: polyoxyethylene 8 stearate polyoxyethylene 40 stearate polyoxyethylene 50 stearate 2) sorbitan esters such as: sorbitan monolaurate sorbitan monopalmitate sorbitan monostearate sorbitan tristearate sorbitan monooleate sorbitan trioleate 3) ethoxylated sorbitan esters such as: polyoxyethylene (20) sorbitan monolaurate polyoxyethylene (4) sorbitan monolaurate polyoxyethylene (20) sorbitan monopalmitate polyoxyethylene (20) sorbitan monostearate polyoxyethylene 20 sorbitan tristearate polyoxyethylene 20 sorbitan monooleate polyoxyethylene 5 sorbitan monooleate polyoxyethylene 20 sorbitan trioleate 4) ethoxylated ethers such as:: polyoxyethylene 4 lauryl ether polyoxyethylene 23 lauryl ether polyoxyethylene 20 cetyl ether polyoxyethylene 10 stearyl ether polyoxyethylene 20 oleyl ether, and 5) ethoxylated alkyl phenols such as: (alkyl phenoxy polyoxyethylene glycol) (C8H17C6H4) (OCH2CH2)OH CAS#9036-19-5 (CgHanC6H4) (OCH2CH2)nOH CAS&num;26-27-38-3 Approximately, 1 5 to 50 parts by weight of this emulsifier water preblend is added per 100 parts by weight of the cyclic polysiloxane when a pastelike silicone-water emulsion is desired.

Up to approximately, 1 000 parts of this preblend can be added per 100 parts of the volatile cyclic polysiloxane in order to provide a low viscosity, lotion-like product.

By adjusting the various process parameters such as content of the volatile cyclic polysiloxane, emulsifying agent, and water as well as the degree of mixing, it is possible to influence the consistency of the product. The silicone-water emulsion can be made in the form of a lotion as well as a paste or cream-like consistency and can be made further viscous in the form of an ointment, salve or a gel. Each of these consistencies is of course, chosen with regard to the desired end use of the product.

These silicon-water emulsions are useful as vehicle for applying from 0.1 to 20,000 parts by weight of one or more epidermal enhancing agents per 100 parts of the emulsion.

This broad range is intended to encompass those products consisting of nearly pure siliconewater emulsion having a small amount of epidermal enhancing agent contained therein, as well as other products which have but a small amount of silicone-water emulsion contained therein. Epidermal enhancing agent refers to an additive of a cosmetic or medicinal nature which is generally regarded as providing beneficial results when applied externally to the skin of a user. The silicone-water emulsion of the present invention is particularly well-suited to serve as a vehicle for applying deodorant or antiperspirant agents to the body.

The preblended water-emulsifier mixture is provided by stirring with moderate heat until a uniform blend is obtained whereupon the cyclic polysiloxane is added and mixed slowly without the need for milling or homogenization. Of course, milling and homogenization may be utilized if desired and it is intended that the term "mixing" encompass these methods as well as mere agitation. Thus, the expression "mixing" is meant to encompass a continuous process utilizing, for example, a Wener Pfleiderer wherein individual streams of the components can be metered into a twin screw processor.

Likewise, a Henschel high speed mixer, a sonolator homogenizer with a vibrating reed and a plain vessel equipped with a mechanical agitator turbine blade will all produe satisfactory results. The silicone-water-emulsifier mixture is then vigorously stirred at 20 to 800C until an emulsion having a desired consistency is achieved. An anti-bacteria agent such as Formalin may be added if desired.

To a 2 liter stainless steel beaker equipped with a hot plate, mechanical air stirrer and thermometer, the water and emulsifier are preblended by adding together and heating to approximately 20 to 800C and preferably 65 to 750C and stirred to achieve a uniform mixture when all the solids have melted. Then the volatile cyclic polysiloxanes, which may be octamethyltetrasiloxane or decamethylpentasiloxane or a combination of these or others are slowly added to the aqueous preblend and stirred vigorously at, approximately, 30 to 800C and preferably, 50 to 600C until a uniform, grease-like emulsion is formed. Small amount of formalin may be added once the product is uniform in order to prevent bacterial activity.Unlike many conventional silicone emulsions, neither colloid milling nor homogenization is required in order to prepare these emulsions, but these means may be utilized if desired.

Alternately, the non-transparent silicone-water emulsion starting materials can be produced with linear polysiloxane oils. For example, a trimethylsilyl chainstopped polydimethyl siloxane fluid can be emulsified with the above-described emulsifying agents and water by blending or homogenizing or by using a colloid mill.

In either case, the consistency of the emulsion can be controlled by the amount of water added.

At a 1 5 to 20% water ievel, the emulsion has a grease-like consistency, but additional water will lower the viscosity of the system to a lotion-like consistency and even more water can be utilized in order to prepare a low viscosity emulsion. The silicone-water emulsions of the present invention are fully dispersible in water.

Additionally, the consistency of the formulation can be further modified by the quantity of the polysiloxanes added. In other words, the more silicone, the thicker the emulsion and more grease-like it will be. A lower ratio of polysiloxanes to water will provide a thinner emulsion.

The emulsifiers themselves influence the consistency of the product. A solid emulsifier like polyoxyethylene 40 stearate will make the emulsion thicker and more grease-like while a more liquidous emulsifier will help provide a lotion-like product.

As can be seen, a wide range of emulsion formulations can be achieved by varying any one of these process parameters: concentration of water, cyclic polysiloxane, or emulsifiers, and the type of emulsifiers, whether solid or liquid.

The above-described emulsions were generally opaque in appearance and indeed sometimes looked milky or cloudy. The continuous phase of such emulsion systems is generally the aqueous phase. Therefore the discontinuous phase is generally a colloidal mixture of oil globules and various selected emulsifying agents. It is generally well known that the emulsifiers have a lipophillic portion which is attracted to the oil globules and a hydrophillic portion which assists in keeping the emulsion from breaking. The present invention utilizes the fact that there are two distinct phases in these emulsion systems in order to provide a new transparent emulsions.

The present invention provides transparent emulsions by incorporating into standard silicone emulsions effective amounts of a class of compounds which will be referred to as optical index adjusting agents. These optical agents are soluble in the water phase of the emulsion system thereby changing the optical environment of the colloids contained therein. As a result when such optical agents are added slowly to these emulsions it is possible to see the emulsion become gradually more and more transparent. The addition of optical agent can cease at any desired end point, or qualitative tests can be utilized to determine the point of greatest optical clarity.It is speculated that these optical agents work by adjusting the difference in optical indices of the two discrete phases until they match, thereby allowing transparency, but it is entirely possible that another mechanism or combination of mechanisms are at work.

The amount of optical adjusting agent which will be necessary to render transparent a particular non-transparent silicone-water emulsion will depend on several factors and will probably be determined on a case by case basis. As a general rule, the more water that is contained in the continuous phase, the more water-soluble optical adjusting agent that will be required. It is believed that in most cases, at least 1 part and probably no more than 100 parts by weight optical agent will be necessary per 100 parts of non-transparent silicone emulsion. In most instances it will be relatively easy to titrate the optical agent on a trial and error basis, merely stopping the addition once the clear emulsion is obtained.Once the amount of optical agent required for a particular emulsion formulation is known, it is a relatively simple matter to pre-mix the optical agent into the formulation so as to obtain a final product in transparent form without the necessity of further adjustment.

The optical index adjusting agents are generally selected from a class of compounds which will be referred to as polyols. Traditionally the word polyol refers to alcohols having three or more hydroxyl groups. It is intended in the present specification that the definition of polyols be extended to cover materials which may not have three hydroxyl groups but in any case are highly ethoxylated as will be described further.

The optical index adjusting agents which may be utilized in the composition and processes of the present invention are quite numerous and as stated above will be described generally as polyols.

Among these optical agents will be the traditional polyols such as glycerol and sorbitol. Other optical agents include the polymeric glycols such as the Ucon type polyols. Ucon is a trademark of the Union Carbide Corporation for polyalkylene glycols, made up of random ethyleneoxide-propyleneoxide copolymers and having a single hydroxyl group at the end of the chain. Another class of useful optical agents are the Pluronics which is a trademark of BASF-Wyandotte Corporation. These Pluronics are a non-ionic series of difunctional block polymers terminating in primary hydroxyl groups and having molecular weights ranging from a thousand to over fifteen thousand, and are polyoxy-alkylene derivatives of propylene glycol. These Pluronic type polyols have two hydroxyl groups, one at either end.Other optical agents include the ethoxylated organic acids or esters such as polyethylene glycol stearate (PEG-40 stearate). Another group of optical agents are the Carbowaxes which is a Union Carbide trademark for polyethylene glycols and methoxypolyethylene glycols. The carbowaxes are generally polymers made up essentially of ethyleneoxide units and having two hydroxyl groups therein.

Also intended as optical agents would be silicone copolymers having copolymeric units selected from the water soluble polyols in addition to its polysiloxane units.

Included among the optical agents can be two other classes of compounds. The Tetronics series which is a trademark of the BASF company is a series of non-ionic polyether block polymers having amine functionality. The other group are the Ethoquads which is a trademark of Armour Industrial Chemical Company and is a series of polyethoxylated Quaternary ammonium chlorides. An additional ethoxy advantage of these Ethoquads lies in the fact that not only do they provide transparent emulsions but they may be also used for disinfectant purposes which is especially useful when the emulsion product is intended for medicinal or cosmetic use.

Instead all of these polyol materials assist in texturizing the feel of the silicone emulsions by increasing their moisturizing capabilities. These properties are particularly useful in skin care products.

Example 1 To a stainless steel beaker equipped with hot plate, mechanical air stirrer, and thermometer, water and selected emulsifiers or blends are added. The water-emulsifier mixture is maintained at 30-350C and stirred to achieve a uniform mixture, with all solids dispersed. Then the selected cyclic polysiloxanes are slowly added to the aqueous system and stirred vigorously to form uniform emulsions. After the water-cyclic emulsion has formed, on optical index adjusting agent is slowly added until a transparent silicone emulsion is obtained. In samples 1 through 4, glycerin or sorbitol were utilized as the optical index adjusting agents. Viscosity was measured on a Brookfield Viscometer at 25cm.

Sample 1 2 3 4 Material % Octamethyltetrasiloxane 59.06 66.5 61.8 56.8 Polysorbate-20 5.52 6 3.9 6.8 Polysorbate-85 ---- ---- 3.9 PEG-40 Stearate 3.94 .2 ~~~~ Sorbitan Laurate 1.57 3.9 2.5 Octyl Phenoxy POE (7) Ethanol .2 .2 Water 21.65 20.6 20.1 23.5 Dodecylsodium Sulfate .39 .5 1.1 .6 Glycerin 7.87 6 ~~~~ Sorbital (70% sol'n) ---- ---- 3.9 9.8 Oleic Acid 7 .7 T.E.A. 7 .7 Properties Appearance Lotion Lotion Paste Liquid Viscosity 8750 cps. 2300 cps. 905,000 cps. 1000 cps.

The consistency of the finished transparent emulsion is controlled by the selection and amount of emulsifiers used. Furthermore, an emulsion as described for Sample 2 can be homogenized without breaking the system and causing oiling out of the cyclic oils.

Example 2 Transparent emulsions utilizing linear siloxanes as the base oil were obtained in the following manner: The selected emulsifiers and siloxane oil are mixed without water in a stainless steel beaker equipped with hot plate, stirrer and thermometer. The emulsifier-oil mixture is stirred and heated to 40-500C. Then a portion of the water is added to form a thick premix. In Sample 8 only, some of the glycerin was also added to the premix. The premix is then milled through a colloid mill under pressure in order to yield a stiff grease-like paste. The pressure in the colloid mill was approximately 20 psi (14000 Kg/m2). The pressure depends entirely on the paste viscosity and is a flexible process parameter. Pressures of from 5 to 30 psi (3500 to 21100 Kg/cm2) would not be unreasonable to one skilled in the art. Additionally, a homogenizer can be utilized instead of the colloid mill. The grease-like paste is then diluted with the remaining water which can contain a bacteriocide when necessary. After the paste is dispersed in the water, the optical index adjusting agent is slowly added to yield a clear, transparent emulsion.

Sample 5 6 7 8 Material % % % 100 cstk. dimethylpolysiloxane oil 21.43 21.43 54.4 71.96 350 cstk. dimethylpolysiloxane oil 21.43 21.43 Trimethylnonyl polyethylene glycol ether .91 1.04 Octyl phenoxy polyethoxy ethanol .91 1.04 ~~~~ Polysorbate 80 3.9 3.9 4.6 Sorbitan laurate ---- ----- .8 .86 Dodecylsodium sulfate - .36 .29 Water 26.28 26.03 18.7 13.32 Sodium salt of alkylaryl polyether sulfonate .36 -- Formalin .07 .07 Sodium benzoate .036 .036 Glycerin 28.574 28.564 8.97 Sorbitol solution (70%) ---- 22.2 Properties Appearance Liquid Liquid Liquid Grease Viscosity 139 cps. 690 cps. 1560 cps. 36000 cps.

Example 3 100 grams of emulsion polymerized silicone emulsion was prepared by blending sufficient amounts of water with octamethylcyclotetrasiloxane and an anionic surfactant, dodecyl benzene sulfonic acid. The mixture was then homogenized to form an emulsion. The polymerization takes place by cooking at greater than about 750C for approximately 2 to 3 hours. Upon cooling, the polymer equilibrates to a final desired molecular weight and ordinarily the polymer can be neutralized with an amine compound such as triethanol amine. To 1 00 grams of this emulsion was added 50 grams of Pluronic L-101 which upon blending provided a stable transparent silicone emulsion lotion.

Example 4 A transparent silicone emulsion lotion was prepared utilizing a silicone copolymer as the optical adjusting agent. A 35% silicone emulsion was prepared from a 60,000 centistoke dimethyl silicone oil utilizing a blend of alkylarylpolyethoxylated emulsifying agents. To 1 00 grams of this mixture was added a combination of optical adjusting agents made up of 50 grams of polysorbate-20 and 20 grams of a silicone copolymer. The silicone copolymer had the general formula M'3D20T wherein M' was (CH3)2005Si-CH2CH2CH2COOH, D was (CH3)2SiO, and Twas CH3SiO15 and which had been esterified with a mixture consisting of Ucon 50 HB 2000 and Ucon 50, HB 660.

Example 5 A hard transparent grease was prepared by combining 64% by weight decamethylpentasiloxane with 10% polysorbate-80 and 5- PEG-40 stearate. These ingredients were blended with moderate heat until they were all melted and a uniform mixture was obtained, whereupon a solution consisting of 20% by weight water and 1 % dodecyl sodiumsulfate (based upon the weight of the total mixture) were added to the previous mixture. Upon blending, a hard clear grease emulsion was obtained. In this example PEG-40 stearate was utilized as the optical adjusting agent and it can be seen that the order of adding the optical agent does not affect the final product.

Example 6 A clear amber lotion of silicone emulsion was obtained by blending 57% by weight octamethyl tetrasiloxane with 7% by weight polysorbate-20 and 2.6% sorbitan laurate. To this mixture was added 1/2% dodecylsodiumsulfate and 23-1/2% water. Then the optical adjusting agent which consisted of 9.3% of sorbitol solution (i.e. 70% of sorbitol in water) was added to the mix and blended till the clear amber lotion was obtained.

Example 7 A non-transparent silicone emulsion which was suitable for use as a cosmetic cream was first prepared in the following manner: To 37 parts by weight polydimethylsiloxane oil having a viscosity of 100 centipoise was added 2.6 parts polysorbate-80, 0.5 parts sorbitan laurate, 0.1 parts sodium benzoate, 33 parts water, and 0.05 parts Givgard DXN which is used as a bacteriocide. These ingredients were blended to form a non-transparent cream emulsion which was made transparent by adding 26 parts (based on the weight of the total mixture) of a Ucon butoxy initiated, hydroxy terminated ethyleneoxide-propylene oxide polyether (Ucon 50-HB-2000) as the optical adjusting agent. The final transparent cream had a viscosity of 55,000 centipoise.

Claims

1. A method of formulating an optically clear silicone emulsion which comprises: (a) forming a non-transparent silicone oil and water emulsion by combining a discontinuous phase of polydiorganosiloxane oil, with a continuous phase of water, and an emulsifying agent or mixture of emulsifying agents; and (b) adjusting the optical clarity of the non-transparent emulsion by combining it with an optical index adjusting agent which is a water soluble polyol or polyether in an amount to render the non-transparent emulsion optically clear.

2. A method as claimed in Claim 1 ,wherein the polydiorganosiloxane oil is a polydimethylsiloxane.

3. A method as claimed in Claim 1 or 2, wherein the polydiorganosiloxane is a volatile cyclic polydiorganosiloxane.

4. A method as claimed in Claim 1 or 2, wherein the polydiorganosiloxane is a linear polydiorganosiloxane.

5. A method as claimed in any preceding Claim, wherein the emulsifying agent is a non-ionic emulsifier selected from ethoxylated fatty acids, sorbitan esters, ethoxylated sorbitan esters, ethoxylated ethers, and ethoxylated alkyl phenols.

6. A method as claimed in any of Claims 1 to 4, wherein the emulsifying agent is an anionic emulsifier selected from alkylbenzene sulfonic acids, salts of alkyl benzene sulfonates, salts of alkyl sulfates, and salts of alkyl or alkylaryl ethoxylated sulfates.

7. A method as claimed in any of Claims 1 to 4, wherein the emulsifying agent is a cationic emulsifier selected from quaternary ammonium chlorides and polyethoxylated quaternary ammonium salts.

8. A method as claimed in any preceding Claim, wherein the optical index adjusting agent is selected from glycerin, sorbitol, polyalkylene glycol, polyoxyalkylene derivatives of propylene glycol, ethoxylated organic acids and esters, methoxypolyethylene glycol, amine-functional polyether block polymers, and polyethoxylated quaternary ammonium chloride.

9. A method as claimed in Claim 8, wherein the optical adjusting agent is further copolymerized with a polydiorgano siloxane.

10. A method as claimed in any preceding Claim wherein the optical index adjusting agent is used in an amount of from 1 to 100 parts by weight per 100 parts by weight of silicone-water emulsion.

11. A method as claimed in any preceding Claim, further comprising the step of adding an epidermal enhancing agent to the optically clear silicone emulsion.

1 2. A method as claimed in Claim 11 , wherein the epidermal enhancing agent is a cosmetic or medicinal agent.

1 3. A method as claimed in Claim 1 and substantially as hereinbefore described with reference to any of the Examples.

14. An optically clear silicone emulsion which comprises: (A) a non-transparent silicone oil and water emulsion comprising a discontinuous phase of polydiorganosiloxane oil, a continuous phase of water, and an emulsifying agent or mixture of emulsifying agents; and (B) an optical index adjusting agent which is a water soluble polyol or polyether in an amount effective for rendering said non-transparent emulsion optically clear.

1 5. An emulsion as claimed in Claim 14, wherein the polydiorganosiloxane oil is a polydimethylsiloxane.

1 6. An emulsion as claimed in Claim 14 or 1 5, wherein the polydiorganosiloxane is a volatile cyclic polydiorganosiloxane.

17. An emulsion as claimed in Claim 14 or 15, wherein the polydiorganosiloxane is a linear polydiorganosiloxane.

18. An emulsion as claimed in any of Claims 14 4 to 17, wherein the emulsifying agent is a non- ionic emulsifier selected from ethoxylated fatty acids, sorbitan esters, ethoxylated sorbitan esters, ethoxylated ethers, and ethoxylated alkyl phenols.

19. An emulsion as claimed in any of Claims 14 to 17, wherein the emulsifying agent is an anionic emulsifier selected from alkylbenzene sulfonic acids, salts of alkyl benzene sulfonates, salts of alkyl sulfates, and salts of alkyl or alkylaryl ethoxylated sulfates.

20. An emulsion as claimed in any of Claims 14 to 17, wherein the emulsifying agent is a cationic emulsifier selected from quaternary ammonium chlorides and polyethoxylated quaternary ammonium salts.

21. An emulsion as claimed in any of Claims 14 to 20, wherein the optical index adjusting agent is selected from glycerin, sorbitol, polyalkylene glycol, polyoxyalkylene derivatives of propylene glycol, ethoxylated organic acids and esters, methoxypolyethylene glycol, amine-functional polyether block polymers, and polymethoxylated quaternary ammonium chloride.

22. An emulsion as claimed in Claim 21, wherein the optical adjusting agent is further copolymerized with a polydiorganosiloxane.

23. An emulsion as claimed in any of Claims 14 to 22, wherein the optical index adjusting agent is used in an amount of from 1 to 100 parts by weight per 100 parts by weight of silicone-water emulsion.

24. An emulsion as claimed in any of Claims 14 to 23, further comprising an epidermal enhancing agent.

25. An emulsion as claimed in Claim 24, wherein the epidermal enhancing agent is a cosmetic or medicinal agent.

26. An emulsion as claimed in Claim 14, and substantially as hereinbefore described with reference to any of the Examples.