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Description  |
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FIELD OF THE INVENTION
This invention relates generally to compositions useful in the personal
care industry. More particularly, it relates to gels which can be used to
prepare various compositions for contact with the skin.
BACKGROUND OF THE INVENTION
Products formulated for use in the personal care industry include many
ingredients. In recent years, many products have included silicones to
obtain certain advantages. The silicones are easy to rub out, softening
the skin and providing lubricity, glossy appearance, and smoothness. They
also provide a water barrier and are not easily washed away. However, they
are not oily or sticky and the film allows the skin to breathe. The
silicones provide these advantages while being inert and safe to use.
However, they tend to flow from or are easily rubbed off the skin. One
method of introducing silicones into personal care products would be to
incorporate them in a compatible and stable gel which could be mixed with
other ingredients in the formulation of personal care products while the
resulting film still retains the excellent properties of the silicone
oils. When silicones are added to conventional gelling agents such as
vegetable or animal waxes, paraffin, or low molecular weight ethylene
vinyl acetate copolymers, the exhibit limited compatibility and often lose
the attractive features of the silicone oils.
The present invention relates to new gels found to be useful in personal
care formulations which inherently provide the advantages of silicones and
represent improvements over gels of the prior art.
SUMMARY OF THE INVENTION
The gels of the invention may be either binary or ternary compositions
which include a telomer-copolymer of ethylene and a silane, and a solvent
for the polymer. A third component may be added, preferably a silicone oil
but a substitute may be used. While the binary compositions are compatible
in all proportions, the ternary compositions are not, and it has been
found that the amount of solvent must be sufficient to permit a stable gel
to be formed.
The telomer copolymers used in gels of the invention are of ethylene and
silane monomers which have the formula:
##STR1##
where: X is 0 or 1
y is 0 or 1
R.sup.1 is H or an aliphatic radical having 1-5 carbon atoms
R.sup.2 is a saturated aliphatic radical having 1-10 carbon atoms or an
aryl radical having no more than two aromatic rings
m is 1-5
n is 1-5
v is 1-3
R.sup.3 is H or an aliphatic radical having 1-4 carbon atoms
said copolymer having a number average weight of from 500-10,000 and
containing from 0.1 to 70% by weight of the silane.
The solvent may be at least one member of the group consisting of fatty
alcohols, fatty esters, polybutene, hydrocarbon oils such as mineral oil,
and petrolatum, animal-derived oils such as lanolin, lanolin alcohol,
squalane, and mink oil or vegetable-derived oils such as jojoba oil,
almond oil, and the like.
Ternary compositions may be made with silicone oils such as polydimethyl
siloxane, polypheny methyl siloxane, cyclomethicone, and the like.
Substitute materials for the silicone oils include such materials as
propylene glycol, castor oil, and the like which are familiar to those
skilled in the art.
Typical ternary compositions are illustrated in the accompanying FIGS. 1-14
with areas marked in which the compositions produce compatible and stable
gels and those areas in which the compositions are unsatisfactory. The
figures also show that binary gels which do not contain silicones or
substitutes are compatible in all proportions. Preferably, binary gels
contain about 8-40 weight percent of the polymer, the remainder being the
solvent.
The stable gels of the invention are useful in formulating various products
for the personal care industry.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate and polydimethyl siloxane.
FIG. 2 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate and cyclomethicone.
FIG. 3 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate and polyphenyl methyl siloxane.
FIG. 4 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate and castor oil.
FIG. 5 is a ternary diagram showing compositions including a copolymer,
hexyldecyl stearate, and cyclomethicone.
FIG. 6 is a ternary diagram showing a composition including a copolymer,
hexyldecyl stearate and polyphenyl methyl siloxane.
FIG. 7 is a ternary diagram showing compositions including a copolymer,
hexyldecyl stearate and cyclomethicone.
FIG. 8 is a ternary diagram showing compositions including a copolymer,
isostearyl alcohol, and polyphenyl methyl siloxane.
FIG. 9 is a ternary diagram showing compositions including a copolymer,
isostearyl alcohol, and propylene glycol.
FIG. 10 is a ternary diagram showing compositions including a copolymer,
isostearyl alcohol, and castor oil.
FIG. 11 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate, and cyclomethicone.
FIG. 12 is a ternary diagram showing compositions including a copolymer,
isopropyl palmitate, and cyclomethicone.
FIG. 13 is a ternary diagram showing compositions including a copolymer,
polybutene, and polyphenyl methyl siloxane.
FIG. 14 is a ternary diagram showing compositions including a copolymer,
polybutene, and polydimethyl siloxane.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Telomer-Copolymers of Ethylene and Silanes
The telomer-copolymers used in gels according to the invention are
described in co-pending applications Ser. No. 898,826, and Ser. No.
124,371 which are incorporated by reference.
The telomer-copolymers used in gels of the invention are of ethylene and
silane comonomers having the formula:
##STR2##
wherein: x is 0 or 1; y is 0 or 1; R.sup.1 is H or an aliphatic radical
having from 1 to 5 carbon atoms; R.sup.2 is a saturated aliphatic radical
having from 1 to 10 carbon atoms or an aryl radical having no more than
two aromatic rings; m is from 1 to 5; n is from 1 to 5; v is from 1 to 3;
R.sup.3 is H or an aliphatic radical having from 1 to 4 carbon atoms.
R.sup.1 is H when x=0.
The copolymers have a number average molecular weight of from 500 to
10,000, preferably from 500 to 5,000, and more preferably from 500 to
3,500. The number average molecular weight is measured by vapor pressure
osmometry or gel permeation chromatography. The copolymer contains from
0.1 to 70%, preferably from 0.2 to 50% and more preferably from 0.2 to 30%
by weight of the silane comonomer moiety.
R.sup.1 is hydrogen or an alkyl radical having from 1 to 5 carbon atoms,
such as methyl, ethyl, isopropyl, butyl, tert-butyl, pentyl, and the like.
R.sup.2 is an alkyl radical having from 1 to 10 carbon atoms, such as
methyl, ethyl, propyl, butyl, tert-butyl, pentyl, hexyl, heptyl, octyl,
and decyl, or an aryl such as benzyl or naphthyl.
R.sup.3 is hydrogen or an alkyl radical having from 1 to 4 carbon atoms
such as methyl, ethyl, propyl, and butyl.
Examples of the vinyltrialkoxysilanes which can be copolymerized with
ethylene include vinyltrimethoxysilane, vinyltriethoxysilane,
vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane,
vinyltripentoxysilane, vinyl-tris(2-methoxyethoxy)silane,
vinyl-tris(2-ethoxyethoxy)silane and the like.
Acryloxyalkyltrialkoxyxilanes which can be copolymerized with ethylene to
form copolymers of the present invention include
gamma-methacryloxypropyltrimethoxysilane,
gamma-acryloxypropyltrimethoxysilane,
gamma-methacryloxyethyltrimethoxysilane,
gamma-methacryloxypropyl-tris(2-methoxyethoxy)silane,
gamma-methacryloxypropyltris(2-ethoxyethoxy)silane, and the like.
The copolymers of ethylene and silane comonomers as described above are
capped by a telogen to form the telomers. The telogens are chain transfer
agents which are a co-reactant material because they react and are
consumed by combining in the polymerized material to form a telomerized
polymer product. This product is a low molecular weight copolymer.
Telogens useful in the present invention include compounds containing
carbon, hydrogen, oxygen, and chlorine and are generally saturated
compounds in that such compounds are free of olefinic saturation. Examples
of useful telogens include alcohols, aldehydes, ketones, chloroform,
carbon tetrachloride, and the like. The preferred telogens contain the
structures C--O--H and C--Cl. Compounds which contain at least one CH or
CH.sub.2 group are generally more reactive than analogous compounds
containing carbon combined with hydrogen in the form of only CH.sub.3
groups. Compounds, especially preferred, have 2-6 aliphatic carbon atoms,
not more than two oxygens, or three chlorine atoms and at least one CH or
CH.sub.2 group. Suitable compounds include alcohols, e.g., methanol;
ethanol; normal and isopropanol; primary, secondary and tertiary butanols;
cyclohexanol; diacetone alcohol; also ethers, e.g., dimethyl, diethyl and
diisopropyl ethers; also ketones, e.g. acetone; methyl ethyl ketone;
isobutyl ketones; cyclohexanone; also esters, e.g., methyl, ethyl, propyl
and butyl formates, acetates, propionates butyrates, malonates,
orthoformates; acids such as acetic, propionic and butyric acids; and the
corresponding acid anhydrides and the corresponding aldehydes; also
ethylene oxide; dioxolane; dioxane, methyl, ethyl, propyl, and butyl
acetals, lactones; furanes; glycol diacetate, etc.; also toluene,
ethylbenzene, cumene, n-propylbenzene, butylbenzenes; amyl benzenes, etc.;
also chloroform and carbon tetrachloride. An especially preferred telogen
is isopropanol. The amount of telogen as well as the particular agent
employed and general reaction conditions are factors influencing the
product and the production of homogeneous materials. Hence, it is also
generally desirable to maintain a substantially constant concentration of
telogen within the reaction zone once equilibrium has been established,
preferably varying by no more than .+-.20%, more preferably by no more
than .+-.10%. The actual amount of the telogen agent may vary widely from
between about 2% to 60%, usually about 2% to 40% based on the total weight
of the feed to or total charge in the reaction zone, more usually between
about 15% to 30% depending on the comonomer, the reaction conditions, and
nature of the product desired.
The copolymerization is carried out at a temperature range of from
100.degree. to 300.degree. C., preferably 100.degree. to 280.degree. C.
and more preferably from 130.degree. to 220.degree. C. The reaction is
carried out at a pressure of from 100 to 700 atmospheres, and preferably
from 300 to 500 atmospheres. The process proceeds until from 30 to 80%,
and preferably from 50 to 70% of each of the monomers is copolymerized.
The average residence time of the reactants in the reactor is from 1 to
400, preferably 20 to 400 minutes, more preferably from 40 to 150 minutes
and yet more preferably from 40 to 100 minutes.
The process requires a telogen of the type described above. The telogen
preferably is maintained in the vapor phase during the process of the
invention and hence the lower boiling materials are preferred. It is,
therefore, generally desirable that the telogens have a boiling point
below 200.degree. C. at atmospheric pressure, preferably below 150.degree.
C. Pressure is a factor having a major influence on the amount of telogen
employed. Generally, larger amounts of telogen and lower pressures tend to
produce the lower molecular weight products. There is from 0.1 to 50 and
preferably 0.3 to 20 times as much telogen by weight as the silane
comonomer. Excessive amounts of the telogens tend to dissolve the product
in the gas phase and upset the desired equilibrium of the reaction. On the
other hand, the smaller amounts of telogen and the higher pressure tend to
produce the higher molecular weight products, and to further such
imbalance beyond permissible limits will result in products which cannot
be effectively recovered and which further may undesirably become
crosslinked.
The process employs an initiator of a free radical type. Such materials
represent well-known classes of catalytic compounds useful in
polymerization reactions and other chemical reactions generally. Among
suitable initators are peroxy, perhalo, azo compounds, etc., which are
moderately stable at 100.degree. C. or above. Specific examples include
hydrogen peroxide, acetyl peroxide, diethyl peroxide, lauroyl peroxide,
benzoyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide,
di-tertiary butyl peroxide, molecular oxygen, acetone oxime,
t-butylper-acetate, t-butylperoctoate, 1-cyano-1(t-butyl-azo)cyclohexane,
2-(t-butylazo)isobutyronitritrile, 2-t-butylazo-2-phenylpropane,
2-t-butylazo-2-cyano-butane, etc. Suitable catalyst proportions are from
0.09 to 20%, and preferably about 0.1 to about 10% by weight of the
telogen or co-reactant injected into the reactor. More preferably there is
from 0.5 to 5% by weight of the catalyst based on the weight of the
telogen. The particular initiator employed must decompose non-explosively
at the reaction temperatures and concentrations.
Solvents
Certain classes of solvents are not useful in personal care applications
and among those which are generally acceptable, there are some which are
particularly suitable for preparing gels with ethylene-silane copolymers.
Particularly useful as solvents in gels according to the invention include
fatty esters, fatty alcohols, polybutene, hydrocarbon oils such as mineral
oil and petrolatum, animal-derived oils such as lanolin, lanolin alcohol,
squalane, and mink oil, or vegetable-derived oils such as jojoba oil,
almond oil, and the like.
In contrast to the two component mixtures of the telomer-copolymer in a
solvent, which are all compatible, it will be clear from the examples that
only some of the binary mixtures of the telomer-copolymers and silicones
are mutually soluble. Therefore, solvents serve to broaden the binary
mixtures which can be used.
Silicones and Substitutes Therefor
Silicones have been used in personal care products since they provide a
number of desirable characteristics. They are easy to rub out and soften
the skin and provide lubricity, a glossy appearance and smoothness, but
they are not oily or sticky. They provide a water barrier and are not
easily washed away, while they are inert and safe to use. However, the
silicones are not entirely compatible when used with conventional gelling
agents and tend to lose the attractive features of the silicones.
Not all silicones are suitable for personal care applications. However,
certain types of silicones have physical properties which make them useful
as previously discussed. Particularly useful materials are polydimethyl
siloxane, polyphenyl methyl siloxane and cyclomethicone, all of which are
commercially available.
Although the silicones are preferred because of their desirable properties,
gels suitable for personal care applications may be made from the
telomer-copolymers described above and substitutes, such as propylene
glycol, castor oil and the like, as will be seen in the examples.
Gel Preparation
Mixtures of the ingredients are prepared by heating and mixing until the
blends appear clear and homogeneous. Generally, temperatures in the range
of 70.degree. to 110.degree. C. are required with the particular
ingredients used in the examples. Then, the clear mixtures are quickly
cooled to ambient temperature while being stirred. Not all of the mixtures
tested were judged to be satisfactory. Some did not form a single clear
phase and were judged to be incompatible. The uniform gels were classified
by particle size as measured by microscopic examination. Those having
particles in the range of 0.01 to 1 micron were stable, while those in the
range of 5 to 30 microns or more were unsable. Borderline gels had
particles in the range of 1 to 5 microns.
In each of the following examples, the three ingredients were heated and
mixed in a vessel with mild agitation until a clear homogeneous solution
was obtained. The container was indirectly cooled with cold water while
agitating with a scraping blade mixer as gel was formed. The size of the
gel particles was determined from photomicrographs. The results are
presented in ternary diagrams which define the incompatible (i.e.,
unsatisfactory) region and show the compositions which are useful in
preparing stable gels. All of the binary mixtures of the copolymers and
solvents produce compatible gels, but the preferred compositions contain
about 8-40 wt. percent of the polymer. Not all the ternary compositions
are compatible as will be seen, and the mixtures are formulated to provide
compatible and stable gels.
Copolymers used were selected from the following group, which illustrates a
range of properties.
__________________________________________________________________________
COPOLYMERS*
Typical Properties
R762A
R762B
R762C
R762D
R724D
R781B
R784G2
__________________________________________________________________________
Hardness, dmm 25.degree.
12.0
4.0 8.0 7.0 -- 30 21
Viscosity, CPS, 140.degree. C.
630 475 417 292 -- 385 430
Drop Point, .degree.C.
93.3
103.7
96.5
100.7
-- -- --
Density 0.899
0.918
0.908
0.912
-- 0.907
0.908
Molecular Weight
MW n (number ave.)
2498
2804
2261
2071
-- -- --
MW w (weight ave.)
23805
6387
14925
8735
-- -- --
Dispersity, (MWn/MWw)
9.2 2.3 6.6 4.2 -- -- --
% Silane monomer
6.2 7.0 7.0 7.0 20.0
24.0
20.9
(vinyltriethoxy silane)
Residual Monomer
0.1 0.11
0.11
0.1 -- -- --
wt. % silane
__________________________________________________________________________
*Allied-Signal Inc.
EXAMPLE 1
Mixtures of R762A, isopropyl palmitate, and Dow Corning 200 silicone oil (a
dimethyl siloxane polymer) were tested as described above. The results are
presented in FIG. 1. A compatible area was defined within which stable
gels were formed and which lies above boundary line A--A in the figure.
Generally, it will be seen that above about 67% by volume of the solvent
(isopropyl palmitate) all mixtures were found to produce stable gels,
while below that value only certain mixtures produced satisfactory gels.
Note that all of the binary mixtures of the copolymer and isopropyl
palmitate produce compatible gels.
EXAMPLE 2
Mixtures of R762D, isopropyl palmitate, and Dow Corning 344 (cyclo
methicone) were prepared according to the above description and the
results are reported in FIG. 2 in the same manner as for Example 1. In
this case, it can be seen that above 35% by volume of the solvent, all
mixtures produce stable gels.
EXAMPLE 3
Mixtures of R762D, isopropyl palmitate, and Dow Corning 556 (a polyphenyl
methyl siloxane oil) were prepared according to the above description. The
results are reported in FIG. 3. A wider range of compositions was found to
be useful since all compositions having more than about 30 vol. % of the
solvent provided stable gels.
EXAMPLE 4
As before, R762D copolymer and isopropyl palmitate were used, but instead
of a silicone oil, castor oil was substituted. The results are shown in
FIG. 4. In this instance only those mixtures having more than about 61
vol. % solvent produced stable gels.
EXAMPLE 5
Mixtures of R762A, hexyl decyl stearate, and Dow Corning 344
(cyclomethicone) were mixed as previously described and the results are
reported in FIG. 5. All mixtures having above about 33 vol. % solvent were
found to provide stable gels.
EXAMPLE 6
Mixtures of R762A, hexyl decyl stearate, and Dow Corning 556 (polyphenyl
methyl siloxane) were prepared as previously described and the results are
reported in FIG. 6. All mixtures having above about 37 vol. % solvent were
found to provide stable gels.
EXAMPLE 7
Mixtures of R762B, hexyl decyl stearate, and Dow Corning 344
(cyclomethicone) were tested as before and the results reported in FIG. 7.
In this instance, all mixtures containing more than about 44 vol. %
solvent produced stable gels.
EXAMPLE 8
Mixtures of R762D, iso stearyl alcohol, and Dow Corning 556 (polyphenyl
methyl siloxane) were tested as previously described and the results
reported in FIG. 8. All mixtures containing more than about 34 vol. %
solvent produced stable gels.
EXAMPLE 9
Mixtures of R762D, iso stearyl alcohol, and propylene glycol were tested
and the results reported in FIG. 9. It will be seen that only a narrow
area is available to the formulator to produce stable gels. At least 75
vol. % of the solvent (iso stearyl alcohol) is required.
EXAMPLE 10
Example 9 was repeated except that castor oil was used rather than
propylene glycol. The results reported in FIG. 10 show that at least 71
vol. % of the solvent is needed to produce stable gels.
EXAMPLE 11
Mixtures of R781B, isopropyl palmitate, and Dow Corning 344
(cyclomethicone) were tested as described above and the results reported
in FIG. 11. In this case, a wide range of mixtures form suitable gels.
EXAMPLE 12
Mixture of R724D, isopropyl palmitate, and Dow Corning 344 were tested and
the results reported in FIG. 12. Again, a wide range of mixtures form
suitable gels.
EXAMPLE 13
Mixtures of R784G2, polybutene (Amoco L-14), and Dow Corning 556
(polyphenyl methyl siloxane) are tested and the results shown in FIG. 13.
A wide range of mixtures form stable gels.
EXAMPLE 14
Mixtures of R781B, polybutene (Amoco L-14), and Dow Corning 200
(polydimethyl siloxane) were tested and the results reported in FIG. 14.
In this instance, only mixtures containing more than about 72 vol. %
polybutene produced stable gels.
EXAMPLE 15
In this and the following examples, typical preparations for the personal
care industry are illustrated and which include stable gels according to
the invention.
An oil-in-water cream was prepared by mixing the following ingredients, the
first three listed being formed into a stable gel before being mixed with
the others.
______________________________________
wt. %
______________________________________
R762A 2.5
Dow Corning 556 2.5
Isopropyl Palmitate 13.5
Arlacel 60 (ICI) 1.0
Tween 60 (ICI) 1.0
Sorbo (70% Sorbitol) (ICI)
5.0
Carbopol 940 (Goodrich)
0.75
Germaben II (preservative)
0.4
Triethanol Amine 0.75
Water 72.6
100.0
______________________________________
EXAMPLE 16
A representative sun-screen cream was formulated as described in Example
15.
______________________________________
wt. %
______________________________________
R762A 2.5
Dow Corning 556 2.5
Isopropyl Palmitate 11.5
Escolol 507* (sunscreen agent)
2.0
(Van Dyk)
Aracel 60 (ICI) 1.0
Tween 60 (ICI) 1.0
Sorbo (70% Sorbitol) (ICI)
5.0
Carbopol 940 (Goodrich)
0.75
Germaben II (preservative)
0.4
Triethanol Amine 0.75
Water 72.6
100.0
______________________________________
*2 ethyl hexyl para dimethyl amino benzoate
EXAMPLE 17
A representative sunscreen gel was formulated as follows:
______________________________________
wt. %
______________________________________
R762A 20
Escolol 507* (Van Dyk)
5
Mineral Oil (70 SSU)
75
100
______________________________________
*2 ethyl hexyl para dimethyl amino benzoate
All ingredients were heated to about 100.degree. C. and stirred until all
the polymer is dissolved. Then the container was cooled in a water bath to
60.degree. C. with agitation.
EXAMPLE 18
A water-in-oil cream was formulated as follows:
______________________________________
wt. %
______________________________________
1. R762D 3.0
2. Beeswax 2.0
3. Lanogene (Amerchol)
5.0
4. Mineral Oil 70 SS
8.2
5. Dow Corning 200 50 CS
1.0
6. 2 Ethyl hexyl stearate
10.0
7. Triglycerol diiosstearate
5.5
8. Germaben II 0.4
9. Sorbo (ICI) 5.0
10. Sodium Borate 0.3
11. Water 59.6
100.0
______________________________________
The first seven ingredients were mixed in a high shear mixer and heated to
85.degree. C., at which point the mixture turns clear. The remaining four
ingredients were heated separately to 85.degree. C., then added to
ingredients 1-7 and mixed in a high shear mixer. A dispersion forms first
which with continued shearing and mixing inverts as the mixture cools to
65.degree.-70.degree. C. to form a thick creamy emulsion. Shearing
agitation was continued as the mixture cools until ready for packaging.
EXAMPLE 19
A sunscreen cream was made with a water-in-oil emulsion having the
following formulation:
______________________________________
wt. %
______________________________________
1. R762D 3.0
2. Beeswax 2.0
3. Lanogene (Amerchol)
5.0
4. Mineral Oil 70 SS
5.2
5. Dow Corning 200 50 CS
1.0
6. 2 Ethyl hexyl stearate
10.0
7. Escolol 507* (sunscreen)
3.0
(Van Dyk)
8. Triglycerol Di-Isostearate
5.5
9. Germaben II 0.4
10. Sorbo 5.0
11. Sodium Borate (anhydrous)
0.3
12. Water 59.6
100.0
______________________________________
*2 ethyl hexyl para dimethyl amino benzoate
The procedure described in Example 18 was followed. In this case,
ingredients 1-8 formed the oil phase and 9-12 formed the water phase.
EXAMPLE 20
A solid stick formulation was prepared having the following composition:
______________________________________
wt. %
______________________________________
R762D 15
Isopropyl Palmitate 45
Dow Corning 344 15
Stearyl alcohol (Alfol 18) (Sherex)
25
100
______________________________________
The ingredients are mixed and heated until a clear solution is obtained.
The solution is cooled and antiperspirants such as 25% aluminum
chlorohydrate or deodorants such as masking perfumes or fragrances are
added before the mixture is poured into molds (a temperature of about
50.degree.-65.degree. C.).
Gels of the invention may also be used with added pigments to make
eyeshadow and similar formulations.
* * * * *
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