Volatile silicone-water emulsions and methods of preparation and use

The present invention provides silicone-water emulsions formed from volatile cyclic polysiloxanes which are emulsified with a preblended mixture of water and a combination of emulsifying agents. Highly ethoxylated nonionic emulsifying agents are particularly well-suited for the formation of stable silicone-water emulsions from volatile cyclic polysiloxanes. These volatile silicone-water emulsions can be combined with epidermal enhancing agents for cosmetic and medicinal purposes.

BACKGROUND OF THE INVENTION 
The present invention discloses compositions of matter and methods for 
producing stable silicone-water emulsions of volatile cyclic polysiloxanes 
without the need for milling or homogenization and which are particularly 
useful in cosmetic and medicinal applications. 
The silicone-water emulsion composition of the present invention is 
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. 
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 nonsilicone 
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 of skin 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 water-repellency of 
silicone fluids are the major reasons for their effectiveness in 
preventing dermatitis. Silicones may also function as emollients, and 
provide 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 present invention provides a method which makes it possible to emulsify 
larger concentrations of cyclic polysiloxanes while at the same time 
eliminating the necessity of milling or homogenization. Additionally, the 
present invention 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. This is a particularly useful property for consumer 
oriented products since these emulsions can therefore, 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 opaque to transparent materials, which 
can be readily formulated into many consumer products and particularly 
antiperspirants and deodorants, etc. Other potential uses for 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 silicone-water 
emulsions are 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. 
It is therefore an object of the present invention to provide a stable 
silicone-water emulsion formed from volatile cyclic polysiloxanes which is 
suitable for cosmetic and medicinal applications. 
It is another object of the present invention to provide methods of 
preparing such silicone-water emulsions and methods for applying epidermal 
enhancing agents. 
SUMMARY OF THE INVENTION 
The present invention provides a silicone-water emulsion and methods of 
preparation and uses wherein said emulsion comprises: 
(A) 100 parts by weight of a cylic polysiloxane or a combination of cyclic 
polysiloxanes selected from theose having the general formula, 
##STR1## 
wherein n is an integer from 3 to 10, R is selected from the group 
consisting of --CH.sub.3, --(CH.sub.2).sub.z CH.sub.3, --CH.sub.2 CH.sub.2 
CF.sub.3, --CH.sub.2 .dbd.CH.sub.2, and --C.sub.6 H.sub.5 and combinations 
thereof and z is an integer from 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; and stirring with moderate 
heat until an emulsion having desired consistency is produced.

DESCRIPTION OF THE INVENTION 
The present invention provides a silicone-water emulsion, which is 
comprised of 100 parts by weight of a cyclic polysiloxane or a combination 
of cyclic polysiloxanes having a general formula, 
##STR2## 
wherein n is an integer from 3 to 10, R is --CH.sub.3, --(CH.sub.2).sub.2 
CH.sub.3, --CH.sub.2 CH.sub.2 CF.sub.3, --CH.sub.2 .dbd.CH.sub.2, or 
--C.sub.6 H.sub.5 or combinations thereof and z is an integer from 1 to 
10. 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 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 100 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. 
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 like: 
polyoxyethylene 8 stearate 
polyoxyethylene 40 stearate 
polyoxyethylene 50 stearate 
(2) sorbitan esters like: 
sorbitan monolaurate 
sorbitan monopalmitate 
sorbitan monostearate 
sorbitan tristearate 
sorbitan monooleate 
sorbitan trioleate 
(3) ethoxylated sorbitan esters 
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 like: 
polyoxyethylene 4 lauryl ether 
polyoxyethylene 23 lauryl ether 
polyoxyethylene 20 cetyl ether 
polyoxyethylene 10 stearyl ether 
polyoxyethylene 20 oleyl ether 
(5) ethoxylated alkyl phenols like 
(alkyl phenoxy polyoxyethylene glycol) 
(C.sub.8 H.sub.17 C.sub.6 H.sub.4)(OCH.sub.2 CH.sub.2).sub.n OH 
CAS #9036-19-5 
(C.sub.9 H.sub.19 C.sub.6 H.sub.4)(OCH.sub.2 CH.sub.2).sub.n OH 
CAS #26-27-38-3 
Approximately, 15 to 50 parts by weight of this emulsifier-water preblend 
is added per 100 parts by weight of the cyclic polysiloxane when a 
paste-like silicone-water emulsion is desired. 
Up to approximately, 1000 parts of this preblend can be added per 100 parts 
of the volatile cyclic polysiloxane inorder 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. 
The silicone-water emulsions useful as a 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 silicone-water 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 particulaly 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" encompasses 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 produce 
satisfactory results. The silicone-water-emulsifier mixture is then 
vigorously stirred at 20.degree. to 80.degree. C. until an emulsion having 
a desired consistency is achieved. An anti-bacterial 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.degree. to 80.degree. C. 
and preferably 65.degree. to 75.degree. C. 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.degree. to 80.degree. C. and preferably, 50.degree. to 60.degree. C. 
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. 
The consistency of the emulsion can be controlled by the amount of water 
added. At a 15 to 20% water level, the emulsion has a grease-like 
consistency, but additional water will ower 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 cyclic polysiloxanes added. In other words, the more 
cyclics--the thicker the emulsion and more grease-like it will be. A lower 
ratio of cyclic polysiloxanes 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 
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. 
EXAMPLE 1 
To a 2 liter stainless steel beaker was added 200 grams water, 82 grams 
polyoxyethylene 40 stearate, and 67 grams sorbitan monostearate which are 
heated at 65.degree. to 75.degree. C. with stirring until a uniform 
mixture was achieved when all the solids had melted. Whereupon, 900 grams 
decamethylpentasiloxane was slowly added to the aqueous system and stirred 
vigorously at, approximately, 50.degree. to 60.degree. C. in order to form 
a uniform grease-like emulsion. Two grams of Formalin was added once the 
product had achieved uniformity, in order to prevent bacterial activity. 
The emulsion was formed without colloid milling nor homogenization and a 
stable, stiff, paste-like emulsion was formed which was suitable for 
serving as a vehicle for applying an epidermal enhancing agent such as a 
deodorant or antiperspirant for application directly to the skin. 
EXAMPLE 2 
The procedure of Example 1 was followed but was modified by the further 
addition of 11% by weight of polyoxyethylene 20 sorbitan monooleate 
whereupon an emulsion having the consistency of a lotion containing, 
approximately, 64% by weight of the pentasiloxane was obtained as was 
suitable for use in cosmetic products. 
EXAMPLE 3 
Following the example of method 1, a water-emulsifier preblend consisting 
of 135 grams of polyoxyethylene 40 stearate and 100 grams sorbitan 
monostearate along with 300 grams of water was prepared. To this was added 
1300 grams of decamethylpentasiloxane, which formed a grease-like 
emulsion. Formalin was added as an anti-bacterial agent. 
EXAMPLE 4 
An emulsifier preblend consisting of 255 grams of water, 82 grams 
polyoxyethylene 40 stearate and 67 grams sorbitan monostearate was 
prepared in accordance with the method in Example 1, whereupon this 
preblend was added to 900 grams of octamethyltetrasiloxane in order to 
form a paste-like emulsion. 
EXAMPLE 5 
An emulsion was formed from a 50--50 cyclic silicone mixture consisting of 
450 grams octamethyltetrasiloxane and 450 grams decamethylpentasiloxane, 
which was formulated with an emulsifier-water preblend consisting of 82 
grams polyoxyethylene 40 stearate and 57 grams sorbitan monostearate and 
280 grams water. A silicone-water emulsion having a grease-like 
consistency was formed. 
EXAMPLE 6 
To 900 grams of decamethylpentasiloxane was added preblend consisting of 60 
grams sorbitan monostearate and 200 grams of 70% octylphenoxypolyethoxy 39 
ethanol and 200 grams water. Following the method described in Example 1 a 
silicone-water emulsion having soft paste-like consistency was formed. 
EXAMPLE 7 
An antiperspirant was formed by combining 100 grams of the silicone-water 
emulsion paste of Example 4 with 20 grams aluminum chlorhydrate in the 
form of Micr-Dry Ultrafine (Trademark of Releis Co.). 
EXAMPLE 8 
A skin freshener was formed by combining 100 grams of the silicone-water 
emulsion paste of Example 6 with 0.25% perfume. 
EXAMPLE 9 
A suntan lotion was formed by combining 100 grams of the silicone-water 
emulsion lotion of Example 2 with 3.0% homosalate and 0.25% perfume.