Note: Descriptions are shown in the official language in which they were submitted.
~2C5~L~7l~
1 J 7018 (R)
ANTIPERSPIRANT COMPOSI1'ION
FIELD OF THE INVENTION
The invention relates to antiperspirant compositions
suitable for topical application to human skin,
particularly solid compositions suitable for use as a
cosmetic stick together with a stick holder.
BACKGROUND TO THE INVENTION
The deodorant and antiperspirant market is dominated
with products based on aluminium or zirconium salts
which are intended to prevent, or at least control,
perspiration at the skin surface, particularly on the
underar~, whilst often simultaneously providing a
perceived degree of deodorancy.
Various physical forms of anti-perspirant compositions
are known, for example aerosol, lotion, or solid form.
When the antiperspirant is provided as a solid
composition for use in "stick" form, it is known to
incorporate the active components which may be present
in the composition, such as for example the aluminium or
zirconium salt and the other components of the
composition, in a cosmetically acceptable vehicle
comprising largely silicone oils (whether volatile or
non-volatile), and a matrix of long chain fatky acids
which act as a structurant.
For example, in US patent 4,126,679 (Armour-Dial), there
is described the possibility of making solid stick
antiperspirant compositions comprising powdered
astringent metallic salts, suspended in a matrix
comprising volatile silicone oils, and 15 to 70%
alcohols selected from long-chain water insoluble
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2 J 701~ (R)
aliphatic alcohols having 16-22 carbon atoms in the
chain.
However, the patent does not describe the possibility of
using long chain fatty alcohols of more than one chain
length for the structurant. Additionally, the examples
all describe formulations which contain as the
structurant either stearyl (C18) alcohol or cetyl (C16)
alcohol.
Further, EP-B-117,070 (Procter & Gamble) describes a
solid stick antiperspirant composition, which comprises
5 to 20% of a long chain fatty alcohol having ~ to 18
carbon atoms in its chain, 35 to 55% of a volatile
polydimethyl silicone, 10 to 70% of an astringent
antiper~spirant salt, and 1 to 3% by weight of the total
long chain fatty alcohol level of the composition of an
additional long chain fatty alcohol selected from C20-
C26 fatty alcohols, or mixtures thereof.
However it is clear from the examples of this patent, in
particular the comparative penetration test of Exa~ple 1
against Example 2, that the addition of relatively small
amounts (i.e. as little as an extra 0.086% by weight of
the total composition~ of what is substantially a C20
long chain fatty alcohol will cause a substantial
increase in hardness of the stick. It is presumably for
these reasons that this reference teaches the addition
of a relatively low amount of long chain alcohols to the
cosmetic stick composition (i.e. a maximum of 3% by
weight of the total long chain fatty alcohol amount in
the composition, or not more than 0.6% by weight of the
total composition).
A further problem with existing solid stick formulations
in general is their lack of high temperature stability.
Current sticks generally exhibit good stability
characteristics at temperatures up to about 40C, but at
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higher temperatures there is a tendency for the
structure of the stick to break down, often leading to
the seepage of silicone oils out of the matrix, and the
loss of beneficial properties. It is already known that,
generally speaking, silicone oils and long chain fatty
alcohols in solid form are not compatable, there being a
tendency for the long chain alcohol to "press" the
silicone oils out of the matrix. This seepage of the
liquid phase from the stick matrix is exaggerated at
elevated temperature.
We have surprisingly found that by the use of specific
long chain alcohols it i6 possible to produce an
antiperspirant stick composition outside of the
teachings of the prior art which has improved
temperà~ture stability, for example at elevated
temperatures such as 50C (a desirable storage
characteristic for antiperspirant compositions designed
for sale in some of the hotter regions of the world),
and which nevertheless maintains the attractive cosmetic
characteristics expected of such sticks
One parameter that has to be very closely controlled
with stick formulations is the hardness of the stick.
This is important not only because it determines the
storage properties of the stick, in particular the
resistance of the stick to degradation caused by
temperature extremes, but also because it determines the
deposition of antiperspirant composition that occurs
; 30 when the stick is used for a given application stroXe.
As can be seen generally from the above prior art, a
favoured structurant for such stick formulations has
comprised largely a long chain fatty alcohol having
around 14-18 carbon atoms in the chain. It is generally
observed when such materials are used as structurants
that as the chain length of the long chain fatty alcohol
4 J 7018 ~ ~)5~ 7
increases, then (for a given amount of long chain fatty
alcohol in the formulation, and at a given temperature)
so the hardness of the stick increases.
This observation has generally proved to be a
disincentive for the manufacturers o~ such products to
include in an antiperspirant composition any substantial
amount (say greater than about 0.6~ by weight of the
total composition) o~ a very long chain ~atty alcohol
(with a carbon chain length of 21 atoms or greater) as a
structurant, since it was previously supposed that such
a stick would be undesirably hard in use.
Viewed against the above mentioned background of prior
art, it has surprisingly been found that cosmetic sticks
with a`~esirable hardness and pay off can be made using
higher amounts of long chain fatty acids than the prior
art suggest would be desirable.
Compositions according to the invention not only have
surprisingly useful hardness properties at ambient
temperatures, but they also enable the antiperspirant
composition to be formulated easily with the desirable
high temperature storage characteristics. It has also
been discovered that stick formulations according to the
invention tend to show a reduced tendency towards
"flaking" compared to other antiperspirant formulations
in which the structurant comprises, for example, only
stearyl alcohol.
- 30
DEFINITION OF THE INVENTION
Accordingly, the invention provides a solid stick
antiperspirant composition suitable for topical
application to human skin, which comprises:
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i. an effective amount o~ an antiperspirant
astringent;
ii. a volatile silicone;
iiio a structurant comprising 0 t:o 40% by weight of the
total composition of alcohols, selected from long-
chain water insoluble aliphzltic alcohols having 12-
20 carbon atoms in the chain, and
iv. an additional structurant comprising 0.8 to 20% by
weight of the total composition of alcohols
selected from long chain water insoluble aliphatic
alcohols having 22-26 carbon atoms in the chain.
DISCLO~;URE OE;' THE INVENTION
The antiperspirant astrinqent
The composition according to the invention comprise~ an
antiperspirant astringent. Examples o~ suitable
astringents include aluminium salts, zirconium salts,
aluminium and/or zirconium complexes, for example
~ aluminium halides, aluminium hydroxy halides, zirconyl
-~ oxyhalides, zirconyl hydroxyhalides, and mixtures
thereof. Useful zirconium salts include zirconium
hydroxy-chloride and zirconium oxychloride. Other
generally used astringents will be known to those
skilled in the art. Preferred astringents include AAZG
(Activated Aluminium Zirconium Glycine), ZAG (Zirconium
Aluminium Glycine), and ~ACH (~ctivated Aluminium
Chlorohydrate).
The amount of antiperspirant astringent present in the
composition according to the invention is from 0.5 to
50%, preferably 1 to 30%, more preferably 5 to 25% by
weight of the total composition.
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The structurant
.
The composition accordiny to the invention also
comprises one or more long chain fatty alcohols as
structurants. Prefexably, the structurant comprises a
mixture of:
- 0 to 40% by weight of the total composition of long
chain water insoluble aliphatic alcohols having 12-
20 carbon atoms in the chain, more preferabl~y
having 16-18 carbon atoms in the chain, and
- 0.8 to 20% by weight o~ the total composition of a
long chain water insoluble aliphatic alcohols
having 22-26 carbon atoms in the chain, more
preferably having 22 carbon atoms in the chain.
The amo~nt of long chain fatty alcohol in the
composition comprises preferably at least 5%, more
preferably at least 10~ by weight.
The Volatile Silicone
The composition according to the invention also
comprises a linear or cyclic volatile silicone.
Useful silicones include cyclic or linear polydimethyl
silicones containing from 3 to 9, prefera~ly 4 to 6,
silicon atoms.
Examples of suitable volatile silicones include
; polydimethyl cyclosiloxanes, having a viscosity of less
than 10mm2s~1, examples of which are DOW CORNING Fluids
344 and 244 ~tetramer) DOW CORNING Fluids 245 and 345
(pentamer), and Union Carbide fluids Silicone 7207 and
Silicone 7158. Other suitable silicones include Stauffer
Chemical SWS-03314, and hexamethyldisiloxane having a
viscosity of not more than 0.65mm2s~l, for example DOW
CORNING 200 Fluid, which has a viscosity of 0.65mm2s~l
as determined in accordance with the method provided in
7 J 7018 (R)
the data sheets provided by the manufacturer on these
compounds.
The preferred volatile silicones are the cyclic forms.
The amount of volatile silicone present in the
composition according to the invention is from 1 to 85%,
preferably from 5 to 70% by weight of the total
composition.
Other Inqredients
The composition according to the invention can
optionally comprise other ingredients, in addition to
those already identified, depending on the nature and
form of~the finished product.
Examples of other ingredients which can optionally be
present in the composition according to the invention
include:
; Emollients, such as non-volatile silicones. Such non-
volatile silicones include polydimethylsiloxane having a
viscosity in excess of 5mm2s~1, for example, from 50 to
1000mm2s~l, such as DOW CORNING 200 Fluids (standard
viscosities 50-1000mm2s~1). Other useful emollients
include ~EG 400 distearate, and ethylene oxide and/or
propylene oxide condensation products having the
following formula:
3 0 RO ( C2H40 ) a ( C3H6) bH
where R is either hydrogen or a hydrocarbon chain having
from about 2 to 20 carbon atoms, and a and k are each
from about 0 to 35 and a + b is from about 5 to 35. One
35 example of such an emollient is Fluid AP, a condensate
of about 14 moles of propylene acid with about 1 mole of
butyl alcohol sold by Union Carbide.
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8 J 7018 (R)
Still further emollients suitable for use in the present
solid stick compositions include fatty acid and fatty
alcohol esters and water insoluble ethers such as those
disclosed in US Patent ~,202,879 to Shelton,
incorporated herein by reference, and mixtures thereof;
thickeners, such as clays, for example Bentone 38;
silica, for example Aerosil 200;
skin feel improvers, such as talc and finely divided
polyethylene, an example of which is ACUMIST B18;
cosmetically acceptable vehicles, such as anhydrous
ethanol and other emollients;
perfumès;
preservatives; and
other cosmetic adjuncts conventionally employed in stick
deodorant products.
A preferred optional component includes a wax such as,
castor wax, Synchrowax HRC, Carnaubau, beeswax, silicone
waxes and glycerol monostearate and mixtures thereof at
levels of from about 1 to 10% preferably 2 to 8%. If
present, the wax is believed to enhance structural
stability of the composition in the molten state.
The ingredients which can optionally be present in the
composition can conveniently form the balance of the
composition.
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9 J 7018 (R)
Product Form
The composition according to the invention can take the
form of a solid product suited to or adapted for topical
application to human skin. One convenient fo~m of the
composition according to the invention is a solid stick,
usually contained in a suitable holder or dispenser to
enable it to be applied to the area of the skin,
particularly the underarm, where control of perspiration
and deodorancy is r~quired.
Use of the composition
The invention also provides for the use of a solid stick
antiperspirant composition, in accordance with the
inventlo~n, as herein ~efined, in perspiration control,
following topical application to human skin.
A preferred embodiment of the invention provides for the
use of a solid stick antiperspirant composition
comprising;
, ~
i. 15-25% by weight of the total composition of an
antiperspirant astringent;
ii. 50-60% by weight of the total composition of a
linear or cyclic volatile silicone;
iii. 12-15% by weight of the total composition of long
chain water insoluble aliphatic alcohols having 16-
18 carbon atoms in the chain.
iv. 0.8-1.5% by weight of the total composition of
long chain water insoluble alphalic alcohols having
22-24 carbon atoms in the chain.
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Examples
The invention is further illustrated by the follow.ing
examples.
Example 1
This illustrates an antiperspirant stick product
according to the invention. The stick had the following
formulation:
% w/w
Volatile silicone -
Cyclomethicone Dow Corning DC 2~5 52.8
Stearyl Alcohol 13.0
Behenyl Alcohol 1.0
AAZG 2~.0
- Castor`~ax MP-70 4.0
; Other ingredients tolOO.O
,~
The stick was prepared according to conventional known
techniques.
For example, the volatile silicone, stearyl alcohol,
behenyl alcohol and castor wax are melted together in a
vessel at a temperature of 65-80C with stirringO Other
2~ ingredients (e.g. talc, emollient and preservatives) are
added slowly with mixing, and subsequently the AAZG is
added slowly with stirring, the temperature of the
vessel whilst the AAZG is added being kept at around
65C . Finally, perfume is added to the composition with
stirring. The molten composition may then be cast into
sticks of the desired shape and cooled.
A stick according to the above composition had
satisfactory properties both on use, and when subjected
to storage at 50C.
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Example 2
This illustrates an antiperspirant stiek product
according to the invention. The stiek had the following
formulation:
;~ ~6 wlw
Volatile silieone -
Cyelomethieone Dow Corning DC 245 54.0
Stearyl Alcohol 10.0
Behenyl Alcohol 5.0
AAZG 22.4
Castor Wax MP-70 ~.0
Other ingredients to100.0
i The sti~k was prepared according to the same method
employed in example 1.
A stick aecording to the above composition had
satisfactory prope.rties both on use, and when subjected
to storage at 50C.
Example 3
A series of antiperspirant stiek produets was made up
aecording to the following formulations, with examples
3-5 being in accordanee with the invention:
12 J 7018 ~'~78
IngredientEx.3Ex.4 Ex.5Ex.6~x.7
~w/w%w/w %w/w%w/w~w/w
Volatile silicone
Cyclomethicane52.8 52.8 52.8 52.8 52.8
Dow Corning DC 245
Stearyl Alcohol12.012.5 13.0 13.5 14.0
B~henyl Alcohol2.0 1.5 1.0 0.5
AAZG 24.024.0 24.024.024.0
Castor Wax MP-704.0 4.0 4.0 4.0 4.0
Other
ingredient~ to 100.0 to 100.0 to 100.0 to 100.0 to 100.0
Five replicate sticks of each of the examples were made up
by conventional techniques, for example as described in
relation to examples 1 and 2~ and suhjected to comparative
tests to measure their penetration and deposition (pay
of~).
~,
Experiment 1.
In the following comparative test, the hardness of the
stick formulation according to the invention was tested
and compared with the control formulation.
Under the test conditions, all of the test sticks were
equilibrated under ambient conditions (i.e 20C, normal
humidity). Identical pieces of cardboard were weighed, and
then the area of the card is completely covered by the
compositions with strokes of the stick to simulate
application to human skin, ensuring the area of the card
is only covered once. The card is then reweighed, and from
this the deposition of each formulation as to the card can
be calculated.
Experiment 2.
In a comparative test, fGrmulations according to examples
1-6 were subjected to standard penetration tests to
determine their hardness using a Precision Penetrometer
(ex Precision Scientific, Chicago, US).
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Accordingly, the distance a standard weighted cone
penetrates the surface of a sample over a speci~ied time
is used as an indication of the hardness of stick
products. A stick sample is taken, and positioned in the
penetrometer. The penetrometer is levelled, and the
penetrometer cone (weight 62.3 g) is adjusted until it
just touches the centre of the side surfac~ of the sample.
The release mechanism of the penetrometer is helcl, the
release level depressed, and held in this position for 5
second, then released. Slowly the rod is depressed which
moves the indicator needle to the recorded position, and
the result recorded to the nearest 0.1 mm.
Result
Formulà$ion Penetration (mm) Deposition, q/unit area
Example 3 50.22 + 4.15 0.134 + 0.037
Example 4 54.63 + 5.28 0.160 + 0.012
Example 5 50.60 + 1.89 0.092 + 0.019
Example 6 45.77 ~ 4.87 0.114 + 0.017
Example 7 44.00 + 2.88 0.062 + 0.008
The experimental results suggest, rather surprisingly,
that as the level of behenyl alcohol in the stick
formulation increases, so the hardness of the stick
decreases, and therefore the deposition of the stick in
comparative circumstances increases.
