U.S. patent application number 10/147271 was filed with the patent office on 2003-06-05 for antiperspirant compositions.
This patent application is currently assigned to Unilever Home and Personal Care USA, Division of Conopco, Inc.. Invention is credited to Clare, Sarah Jayne, Franklin, Kevin Ronald, Gransden, Kathryn Elizabeth, Murphy, Angela Mary, Turner, Graham Andrew.
Application Number | 20030103920 10/147271 |
Document ID | / |
Family ID | 9895386 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030103920 |
Kind Code |
A1 |
Clare, Sarah Jayne ; et
al. |
June 5, 2003 |
Antiperspirant compositions
Abstract
A firm solid antiperspirant composition having a continuous
phase comprising water-immiscible liquid containing i) one or more
gelating structurant materials which form a network of fibres
within the liquid, and ii) a polymeric thickener which has an
organic polymer backbone containing at least five monomer repeat
units, which polymer has the ability to increase the viscosity of
the water-immiscible liquid in the absence of the gelating
structurant materials; and iii) an antiperspirant active dispersed
in the continuous phase, said composition being free from or
containing less than 3% by weight of a fatty alcohol that is solid
at 20.degree. C.
Inventors: |
Clare, Sarah Jayne;
(Merseyside, GB) ; Franklin, Kevin Ronald;
(Merseyside, GB) ; Murphy, Angela Mary;
(Merseyside, GB) ; Gransden, Kathryn Elizabeth;
(Merseyside, GB) ; Turner, Graham Andrew;
(Merseyside, GB) |
Correspondence
Address: |
UNILEVER
PATENT DEPARTMENT
45 RIVER ROAD
EDGEWATER
NJ
07020
US
|
Assignee: |
Unilever Home and Personal Care
USA, Division of Conopco, Inc.
|
Family ID: |
9895386 |
Appl. No.: |
10/147271 |
Filed: |
May 16, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10147271 |
May 16, 2002 |
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09902276 |
Jul 10, 2001 |
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6391291 |
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Current U.S.
Class: |
424/65 |
Current CPC
Class: |
A61Q 15/00 20130101;
A61K 8/73 20130101; A61K 8/63 20130101; A61K 8/027 20130101 |
Class at
Publication: |
424/65 |
International
Class: |
A61K 007/32 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2000 |
GB |
0016937.5 |
Claims
We claim:
1. A firm solid antiperspirant composition having a continuous
phase comprising water-immiscible liquid containing: i) one or more
gelating structurant materials which form a network of fibres
within the liquid, and ii) a polymeric thickener which has an
organic polymer backbone containing at least five monomer repeat
units, which polymer has the ability to increase the viscosity of
the water-immiscible liquid in the absence of the gelating
structurant materials; and iii) an antiperspirant active dispersed
in the continuous phase said composition being free from or
containing less than 3% by weight of a fatty alcohol that is solid
at 20.degree. C.
2. A composition according to claim 1 which does not contain more
than 3% of any material which is solid at 30.degree. C., is molten
at 95.degree. C., soluble in the water-immiscible liquid at
95.degree. C., but does not form a network of fibres in the
water-immiscible liquid.
3. A composition according to claim 1 wherein the total amount of
said fibre-forming structurant (i) and said polymeric thickener
(ii) is from 3% to 18% by weight of the composition.
4. A composition according to claim 3 wherein the total amount of
said gelating structurant (i) and said polymeric thickener (ii) is
from 4% to 16% by weight of the composition.
5. A composition according to claim 1 wherein the total amount of
fibre-forming gelating structurant material is from 3% to 15% by
weight of the composition.
6. A composition according to any one of the preceding claims
wherein the percentage of fibre-forming structurant is greater than
the percentage of polymeric thickener by weight of the
composition.
7. A composition according to claim 7 wherein the fibre forming
structurant and polymeric are present in a weight ratio in the
range of from 2:1 to 40:1.
8. A composition according to claim 1, 3 6 or 7 wherein the organic
polymeric thickener comprises a polysaccharide esterified with a
monocarboxylic acid of 8 to 22 carbon atoms.
9. A composition according to claim 8 containing from 0.5% to 5% by
weight of the composition of a said esterified polysaccharide.
10. A composition according to claim 8 or claim 9 wherein the
esterified polysaccharide is a dextrin fatty acid ester having the
formula 9wherein each R group, individually, is a hydrogen or an
acyl group of up to 22 carbon atoms, provided that at least one R
group per glucose unit is an acyl group of 8 to 22 carbon atoms,
and m has a value from about 20 to 30.
11. A composition according to any one of claims 1, 3, 6 or 7
wherein the organic polymeric thickener comprises hydrogenated
styrene-isoprene copolymer.
12. A composition according to claim 1 characterised in that the
water-immiscible liquid contains a volatile silicone and optionally
a non-volatile silicone and/or a non-silicone hydrophobic organic
liquid selected from hydrocarbons, hydrophobic aliphatic esters,
aromatic esters and hydrophobic alcohols.
13. A composition according to claim 1 wherein the water-immiscible
liquid contains silicone oil in an amount which is at least 10% by
weight of the composition.
14. A composition according to claim 1 wherein the composition is a
suspension with a particulate solid material dispersed in said
continuous phase.
15. A composition according to claim 1 wherein the composition is
an emulsion with a hydrophilic, preferably water-miscible, disperse
phase in addition to said water-immiscible liquid continuous
phase.
16. A composition according to claim 15 wherein the disperse phase
contains a diol or polyol.
17. A composition according to claim 15 which contains from 0.1% to
10% by weight of a nonionic emulsifier.
18. A composition according to according to claim 1 wherein the
antiperspirant active comprises an aluminium and/or zirconium
halohydrate, an activated aluminium and/or zirconium halohydrate,
or an aluminium and/or zirconium complex or an activated aluminium
and/or zirconium complex.
19. A composition according to claim 18 wherein the antiperspirant
active comprises a halohydrate or complex in which aluminium and
zirconium are both present.
20. A composition according to claim 1 wherein the proportion of
antiperspirant active is from 5 to 40% by weight of the
composition.
21. An antiperspirant product comprising a dispensing container
having an open end for extrusion of the contents of the container,
means for urging the contents of the container towards the said
open end, and a stick of composition according to claim 1
accommodated within the container.
22. A method of making a composition according to claim 1
comprising: mixing the ingredients of the composition and, before,
during or after mixing, heating the ingredients of the composition
to a temperature at which continuous phase is a mobile liquid in
which the fibre-forming structurant material (i) and the organic
polymer thickener (ii) are dissolved in the water-immiscible
liquid, introducing the composition, at a temperature at which it
is mobile, into containers, causing or allowing cooling of the
containers, until the temperature of the composition in the
containers has fallen below 30.degree. C.
23. A method according to claim 22 wherein the step of mixing and
heating the ingredients comprises mixing the fibre-forming
structurant and the polymeric thickener with the water immiscible
liquid and, before, during or after mixing, heating them to a
temperature at which continuous phase is a mobile liquid in which
the fibre-forming structurant material and the organic polymer
thickener are dissolved in the water-immiscible liquid, then adding
a solution of antiperspirant active.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to antiperspirant compositions
with sufficient rigidity to sustain their own shape. The usual form
of such compositions is a stick.
BACKGROUND OF THE INVENTION
[0002] Topically applied antiperspirant compositions are in
widespread use throughout much of the world, in order to enable
their users to avoid or minimise wet patches on their skin,
especially in axillary regions. Antiperspirant formulations have
been applied using a range of different applicators depending on
the individual preferences of consumers, including aerosols,
roll-ons, pump sprays, sticks and so-called mushroom applicators
which are used to apply cream formulations. In some parts of the
world, sticks are especially popular. The term stick traditionally
indicates a bar of material with a solid appearance which is
usually housed within a dispensing container and which retains its
structural integrity and shape whilst being applied. When a portion
of the stick is drawn across the skin surface a film of the stick
composition is transferred to the skin surface. Although the stick
has the appearance of a solid article capable of retaining its own
shape for a period of time, the material usually has a structured
liquid phase so that a film of the composition is readily
transferred from the stick to another surface upon contact.
[0003] For use, the stick is applied directly to the skin of the
user. This contrasts with soft solid compositions which exist as a
stick within their container but for use a portion is extruded from
the container through apertures which have smaller cross section
than the body of composition which is being made to flow out
through these apertures.
[0004] Antiperspirant sticks have been made with a variety of
different types of composition. Suspension sticks contain a
particulate antiperspirant active suspended in a structured carrier
material which is generally water-immiscible and may well be
anhydrous. Solution sticks have the antiperspirant active dissolved
in a structured carrier which is polar and may be aqueous or may be
based on a non-aqueous polar solvent such as ethanol. A third form
of stick is an emulsion of two phases where the continuous phase is
structured so that the composition is able to sustain its own
shape, the antiperspirant active being dissolved in the more polar
of the two phases present. In some emulsion sticks the
antiperspirant active is dissolved in an aqueous disperse phase
while the continuous phase is a liquid water-immiscible phase so
that the composition can be classified as a water-in-oil emulsion.
The classification into suspension, emulsion and solution types can
be applied to both firm and soft solid compositions.
[0005] There is substantial literature on the structuring or
thickening of antiperspirant compositions which is frequently
accomplished using some form of thickening agent as part of the
composition.
[0006] It has been common practice for sticks to be structured by
incorporating fatty alcohol into the composition, often accompanied
by a smaller amount of castor wax. Sticks which are structured with
fatty alcohol tend to leave visible white deposits on application
to human skin. These deposits can also transfer onto clothing when
it comes into contact with the skin and the wearer can, for
example, find white marks on the armhole of a sleeveless garment.
Fatty alcohols are often regarded as coming within the general
category of waxy materials, but we have observed that they are a
more significant source of white deposits than other waxy
materials.
[0007] There have been some disclosures of antiperspirant stick
compositions where structuring to a shape-sustaining stick has been
accomplished without using a fatty alcohol. Amongst these
disclosures there has sometimes been recognition that white
deposits are avoided.
[0008] The thickening of organic liquids with polyamides in order
to make antiperspirant compositions has been disclosed in U.S. Pat.
No. 5,500,209. Typically, compositions exemplified in this document
are thickened with 15% or more of thickening polymer, and are
emulsions in which the antiperspirant active is dissolved in water
or hydrophilic solvent.
[0009] WO 97/36572 WO 97/36573 and WO 99/06473 all disclose the
structuring of antiperspirant sticks with siloxane polymers which
incorporate amide and/or other hydrogen bonding substituent
groups.
[0010] We have found that when emulsion sticks are structured
solely with such polymer according to these prior documents, the
result is unsatisfactory. Over 10% polymer was required to obtain
firm sticks, but these were then found to have a rubbery, tacky
feel. Moreover pieces could be broken off easily.
[0011] WO 97/13496 employs polyethyleneformamides to form an
antiperspirant gel in an aqueous or water-miscible medium. It
provides no teaching of relevance to structuring a water-immiscible
liquid carrier.
[0012] U.S. Pat. No. 4,265,878, U.S. Pat. No. 4,725,431, U.S. Pat.
No. 4,732,754, U.S. Pat. No. 4,719,103 and U.S. Pat. No. 4,704,271
disclose antiperspirant stick compositions in which a solution of
antiperspirant active in aqueous solution is dispersed in a
hydrophobic continuous phase of hydrocarbon or silicone oil. This
hydrophobic continuous phase is structured to provide a rigid stick
by the incorporation of a substantial amount of waxy material, such
as stearyl alcohol or spermaceti wax.
[0013] U.S. Pat. No. 4,822,602 exemplifies a composition structured
with sodium stearate which restricts the choice of antiperspirant
active to an unusual active which does not precipitate as an
insoluble salt on contact with stearate, but is of poor efficacy.
The sodium stearate causes phase transfer of a water-miscible
constituent. A stick prepared in accordance with this example was
found to have a tacky, draggy feel on handling.
[0014] In some cases structuring has been achieved by the
incorporation of a structurant (also referred to as a gellant or
gelling agent) which causes the liquid to gel upon cooling from an
elevated temperature. Gel formation takes place as an exothermic
event within a temperature range referred to as the gel point; upon
reheating, melting of the gel takes place as an endothermic event
within a temperature range. Such gels can be disrupted by shearing
and do not recover their structure for a long time, if at all
unless remelted, although a small partial recovery may be
observed.
[0015] U.S. Pat. No. 5,429,816 discloses an antiperspirant stick in
which a solid antiperspirant active is dispersed in a carrier
mixture of silicone and other oil which is gelled with 12-hydroxy
stearic acid used jointly with a secondary gellant which is an
n-acyl-amino acid amide. The deposit on skin is said to be a low
visible residue, rather than an opaque white deposit. A number of
other documents provide similar disclosures of suspension sticks
structured with these materials.
[0016] U.S. Pat. No. 5,480,637 discloses the preparation of an
antiperspirant stick in which a suspension of solid, encapsulated
aluminium chlorohydrate dispersed in silicone oil is gelled with
12-hydroxy stearic acid used jointly with a small amount of an
alkyl methyl siloxane polymer. U.S. Pat. No. 5,492,691, U.S. Pat.
No. 5,455,026 and EP-A-616842 are somewhat similar but do not
require the siloxane polymer. Although U.S. Pat. No. 5,480,637
teaches the use of siloxane polymer to promote the gelling action
of 12-hydroxystearic acid, we have found that it has very little
effect.
[0017] U.S. Pat. No. 5,840,286 is concerned with anhydrous
suspension sticks containing a gelling agent and requires that the
composition is substantially free of organic polymeric gellant.
[0018] U.S. Pat. No. 4,719,102, U.S. Pat. No. 4,725,430, U.S. Pat.
No. 5,200,174 and U.S. Pat. No. 5,346,694 all disclose sticks
formed by mixing two solutions both of which contain a substantial
amount of a polar solvent. One contains dibenzylidene sorbitol or a
similar compound as a structurant while the other contains the
antiperspirant active dissolved in an alcohol solution with little
water present. The alcoholic solution generally contains ethanol or
a mixture of ethanol and propylene glycol. The two solutions become
one by mixing, and can incorporate a water-soluble polymer.
Formulating a stick to contain substantial amounts of polar organic
solvent has associated disadvantages. If the polar solvent is
volatile, like ethanol, the stick gives a cooling sensation when
applied. Some cooling may be desired but too much may prove
unacceptable to consumers. Polar but less volatile solvents such as
water-immiscible diols tend to make a stick feel tacky when touched
and hence give a sensation of stickiness and drag when applied to
skin.
[0019] Fatty acyl amino acid amides, 12-hydroxy stearic acid and
dibenzylidene sorbitol are all examples of compounds which are able
to gel and hence structure at least some organic liquids, (although
dibenzylidene sorbitol is not suitable if an acidic aqueous phase
is present, because it will be hydrolysed rapidly). It has been
shown that they function by forming a network of fibres which
extend throughout the liquid and thereby give it rigidity. When the
gel melts these fibres dissolve in the liquid.
[0020] WO 99/66895 discloses stick shaped cosmetic formulations
containing essentially a linear aliphatic alcohol such as stearyl
alcohol and 12-hydroxystearic acid. Optionally an organic thickener
can be incorporated. Such formulations inevitably have impaired
visual deposition because of the incorporation of the linear
aliphatic alcohol.
SUMMARY OF THE INVENTION
[0021] We have now found that a good combination of properties can
be achieved by gelation with a gel-forming structurant and
supplementing this with a polymeric thickener which is organic
rather than a silicone polymer.
[0022] According to a first aspect of this invention there is
provided a firm solid antiperspirant composition having a
continuous phase comprising water-immiscible liquid containing:
[0023] i) one or more gelating structurant materials which form a
network of fibres within the liquid, and
[0024] ii) a polymeric thickener which has an organic polymer chain
containing at least five monomer repeat units and providing a
polymeric main chain consisting of carbon atoms optionally together
with oxygen or nitrogen, which polymer has the ability to increase
the viscosity of the water-immiscible liquid in the absence of the
gelating structurant materials; and
[0025] iii) an antiperspirant active dispersed in the continuous
phase which composition is free from or contains less than 3% by
weight of a fatty alcohol which is solid at 20.degree. C.
[0026] A composition of this invention may be a suspension of
particulate antiperspirant active, or an emulsion in which the
disperse liquid phase is a solution of antiperspirant active in
water or other hydrophobic solvent.
[0027] In either case, a composition of this invention is a firm
solid which is able to sustain its own shape if left
unsupported.
[0028] The gelating structurant material may be a single such
material, a mixture of such materials or a plurality of materials
which co-operate to form a gelating system. The total amount of
such structuring materials is preferably sufficient to gel the
water-immiscible liquid, in absence of the polymeric thickener, to
a state which is able to sustain its own shape at 20.degree. C. at
least for a time.
[0029] The polymeric thickener must have an organic backbone, i.e.
main chain, containing carbon atoms, and possibly other atoms such
as oxygen and nitrogen. Silicon atoms should be substantially
absent from the backbone chain. The presence of silicon atoms in
side chains or in terminal or substituent groups is not ruled out
although preferred polymers do not contain any silicon, and so can
be classed as silicon-free organic polymers. These structural
requirements distinguish from siloxanes which have a polymeric
chain of silicon and oxygen atoms, with carbon atoms in substituent
and terminal groups.
[0030] Preferred organic polymers for this invention are
polysaccharides esterified with fatty acyl groups containing at
least eight carbon atoms. The amount of organic polymer is
preferably such that, in the absence of the gelating structurant
materials, it will thicken the water immiscible liquid to a
viscous, yet still mobile state which is incapable of sustaining
its own shape, with a consequence that if disturbed it will be seen
to flow to restore a level surface.
[0031] Alternative organic polymer thickening agents comprise block
copolymers of styrene with an alkylene containing up to 5
carbons.
[0032] Compositions of the present invention can provide:
[0033] satisfactory hardness of the composition,
[0034] satisfactory sensory perception when applied to the skin by
the user
[0035] avoidance of highly visible opaque deposits on skin or
clothing
[0036] Incorporation of the polymer as a supplement to the gelating
structurant can provide one or more of:
[0037] an increase in hardness of the composition
[0038] an increase in stability of the composition, notably a
reduction in syneresis, that is to say liquid weeping from the body
of composition
[0039] improved efficacy.
[0040] In order to promote good sensory properties at the time of
use it is preferred to include silicone oil in the water-immiscible
carrier liquid. The amount of silicone oil may be at least 10% by
weight of the composition and/or at least 40% by weight of the
water-immiscible carrier liquid.
[0041] Ethanol gives a cooling effect on application to skin,
because it is very volatile. It is preferred that the content of
ethanol or any monohydric alcohol with a vapour pressure above
1.3kPa (10 mm Hg) is not over 15% better not over 8% by weight of
the composition.
[0042] Fatty alcohols which are solid at room temperature of
20.degree. C., such as stearyl alcohol, lead to deposits with an
opaque white appearance and are kept to low concentration,
preferably not more than 2% by weight or entirely excluded. Such
fatty alcohols are commonly linear aliphatic alcohols containing at
least 12 carbons, of which stearyl alcohol is the example of such
linear alcohols most commonly encountered in antiperspirant
compositions. As already mentioned, fatty alcohols are often
regarded as coming within the general category of waxy materials.
More generally the term "wax" is conventionally applied to a
variety of materials and mixtures (including some fatty alcohols)
which have some diversity in chemical structure but similarity in
physical properties. The term generally denotes materials which are
solid at 30.degree. C., often also solid up to 40.degree. C., but
which melt to a mobile liquid at a temperature below 95.degree. C.
usually below 90.degree. C.
[0043] Preferably the composition does not include more than 3% of
any material which is solid at 30.degree. C. but is molten at
95.degree. C. and at 95.degree. C. is soluble in the
water-immiscible liquid of the continuous phase, and which is
unable to form a network of fibres in the continuous phase on
cooling to 20.degree. C.
[0044] A composition of this invention will generally be marketed
in a container by means of which it can be applied at time of use.
This container may be of conventional type.
[0045] A second aspect of the invention therefore provides an
antiperspirant product comprising a dispensing container having an
open end for delivery of the contents of the container, means for
urging the contents of the container to the said open end, and a
stick of composition of the first aspect of the invention in the
container.
[0046] The compositions of this invention can be made and packed by
heating their constituents to form a liquid composition, mixing at
temperatures where the composition is freely mobile, pouring into
containers for retail sale and leaving these compositions to cool
to room temperature. The composition thickens and solidifies as it
cools. Therefore, in a third aspect, this invention provides a
method of making a composition as specified above, by steps of
[0047] mixing the ingredients of the composition, and before,
during or after mixing, heating the ingredients of the composition
to a temperature at which the continuous phase is a mobile liquid
in which the gelating structurant material (i) and the polymeric
thickener (ii) are dissolved in the water-immiscible liquid,
followed by:
[0048] introducing the mixture into a mould which preferably is a
dispensing container, and then
[0049] cooling or permitting the mixture to cool to a temperature
at which it is solidified, suitably a temperature below 30.degree.
C.
[0050] In many instances, the method will commence with mixing the
ingredients of the continuous phase and before, during or after
this mixing heating these constituents to a temperature at which
the continuous phase is a mobile liquid in which the gelating
structurant material (i) and the polymeric thickener (ii) are
dissolved in the water-immiscible liquid, followed by mixing a
disperse phase comprising antiperspirant active into the continuous
phase, and thereafter introducing the resulting mixture into a
mould and cooling or allowing cooling.
[0051] As already indicated the disperse phase may be
antiperspirant active in particulate form, or may be solution of
antiperspirant active in a polar, possibly aqueous, solvent.
[0052] According to a fourth aspect of the present invention, there
is provided a method for preventing or reducing perspiration on
human skin comprising topically applying to the skin a composition
according to the first aspect of this invention comprising an
antiperspirant active, a water-immiscible liquid carrier and a
structurant therefor.
DETAILED DESCRIPTION AND EMBODIMENTS
[0053] As mentioned above, the invention requires both an organic
polymeric thickener and another structurant within a
water-immiscible liquid phase. Other materials may also be present
depending on the nature of the composition. The various materials
will now be discussed by turn and preferred features and
possibilities will be indicated.
[0054] Water-immiscible Liquid
[0055] The water-immiscible liquid comprise one or a mixture of
materials which are relatively hydrophobic so as to be immiscible
in water. Some hydrophilic liquid may be included, provided the
overall liquid mixture is immiscible with water. Generally, this
liquid or liquid mixture (when in the absence of polymeric
thickener or other structurant) will be freely mobile at
temperatures of 15.degree. C. and above. It may have some
volatility, but its vapour pressure will generally be less than 4
kPa (30 mmHg) at 25.degree. C. so that the material can be referred
to as an oil or mixture of oils. More specifically, it is desirable
that at least 80% by weight of the liquid should consist of
materials with a vapour pressure not over this value of 4 kPa at
25.degree. C.
[0056] It is preferred that the liquid or liquid mixture includes a
volatile liquid silicone, i.e. liquid polyorganosiloxane. To class
as "volatile" such material should have a measurable vapour
pressure at 20 or 25.degree. C. Typically the vapour pressure of a
volatile silicone lies in a range from 1 or 10 Pa to 2 kPa at
25.degree. C.
[0057] It is desirable to include volatile silicone because it
gives a "drier" feel to the applied film after the composition is
applied to skin.
[0058] Volatile polyorganosiloxanes can be linear or cyclic or
mixtures thereof. Preferred cyclic siloxanes include
polydimethylsiloxanes and particularly those containing from 3 to 9
silicon atoms and preferably not more than 7 silicon atoms and most
preferably from 4 to 6 silicon atoms, otherwise often referred to
as cyclomethicones. Preferred linear siloxanes include
polydimethylsiloxanes containing from 3 to 9 silicon atoms. The
volatile siloxanes normally by themselves exhibit viscosities of
below 10.sup.-5 m.sup.2/sec (10 centistokes), and particularly
above 10.sup.-7 m.sup.2/sec (0.1 centistokes), the linear siloxanes
normally exhibiting a viscosity of below 5.times.10.sup.-6
m.sup.2/sec (5 centistokes). The volatile silicones can also
comprise branched linear or cyclic siloxanes such as the
aforementioned linear or cyclic siloxanes substituted by one or
more pendant --O-13 Si(CH.sub.3).sub.3 groups. Examples of
commercially available silicone oils include oils having grade
designations 344, 345, 244, 245 and 246 from Dow Corning
Corporation; Silicone 7207 and Silicone 7158 from Union Carbide
Corporation; and SF1202 from General Electric.
[0059] The hydrophobic liquid employed in compositions herein can
alternatively or additionally comprise non-volatile silicone oils,
which include polyalkyl siloxanes, polyalkylaryl siloxanes and
polyethersiloxane copolymers. These can suitably be selected from
dimethicone and dimethicone copolyols. Commercially available
non-volatile silicone oils include Dow Corning 556 and Dow Corning
200 series.
[0060] The water-immiscible liquid may contain from 0 to 100% by
weight of one or more liquid silicones. Preferably, there is
sufficient liquid silicone to provide at least 10%, better at least
15%, by weight of the whole composition. If silicone oil is used,
volatile silicone preferably constitutes from 20 to 100% of the
weight of the liquid or liquid mixture. In many instances, when a
non-volatile silicone oil is present, its weight ratio to volatile
silicone oil is chosen in the range of from 1:3 to 1:40.
[0061] Silicon-free hydrophobic liquids can be used instead of, or
more preferably in addition to liquid silicones. Silicon-free
hydrophobic organic liquids which can be incorporated include
liquid aliphatic hydrocarbons such as mineral oils or hydrogenated
polyisobutene, often selected to exhibit a low viscosity. Further
examples of liquid hydrocarbons are polydecene and paraffins and
isoparaffins of at least 10 carbon atoms. Although polyisobutene
and polydecene are polymeric in nature, they are mobile liquids at
room temperature of 20.degree. C. and do not cause thickening of
other hydrophobic oils.
[0062] Some hydrophobic aliphatic or aromatic esters are liquids
which may be used. These also may be used as only part of a liquid
mixture.
[0063] Suitable aliphatic esters contain at least one long chain
alkyl group, such as esters derived from C.sub.1 to C.sub.20
alkanols esterified with a C.sub.8 to C.sub.22 alkanoic acid or
C.sub.6 to C.sub.10 alkanedioic acid. The alkanol and acid moieties
or mixtures thereof are preferably selected such that they each
have a melting point of below 20.degree. C. These esters include
isopropyl myristate, lauryl myristate, isopropyl palmitate,
diisopropyl sebacate and diisopropyl adipate.
[0064] Suitable liquid aromatic esters, preferably having a melting
point of below 20.degree. C., include fatty alkyl benzoates.
Examples of such esters include suitable C.sub.8 to C.sub.18 alkyl
benzoates or mixtures thereof.
[0065] As mentioned above, aliphatic alcohols which are solid at
20.degree. C., such as stearyl alcohol are preferably absent or
else present in low concentration such as less than 5% by weight of
the whole composition since these lead to visible white deposits
when a composition is used.
[0066] However, aliphatic alcohols which are liquid at 20.degree.
C. may be employed. These include branched chain alcohols of at
least 10 carbon atoms such as isostearyl alcohol and octyl
dodecanol.
[0067] Silicon-free liquids can constitute from 0-100% of the
water-immiscible liquid, but it is preferred that silicone oil is
present and that the amount of silicon-free liquid constituents
preferably constitutes no more than 50 or 60% and in many instances
from 20 to 60% by weight of the liquid mixture.
[0068] Organic Polymeric Thickener
[0069] A number of organic polymers are effective to increase the
viscosity of hydrophobic liquids, although some polymers do not do
so.
[0070] A material which is suitable as an organic polymeric
thickener will generally possess the following characteristics:
[0071] i) it will contain residues of at least 5 possibly many more
than 7) monomer units bonded together into a polymer chain;
[0072] ii) it should dissolve sufficiently on heating in
hydrophobic oils, more specifically in the water-immiscible liquid
of the continuous phase;
[0073] iii) after heating to dissolve and cooling to 20.degree. C.,
it will increase the viscosity of the water-immiscible liquid of
the continuous phase in the absence of other structurant: this
should be observable with the polymer dissolved at a concentration
not exceeding 6% by weight;
[0074] Preferably, under these conditions, it will bring about a
viscosity increase of at least 100 mPa.sec, better at least 250
mPa.sec when viscosity is measured with a Brookfield viscometer
using a T-bar spindle at 10 rpm at 20.degree. C. The choice of a
type B, type C or type D T-bar spindle will depend on the viscosity
of the system being measured. Provided the spindle is appropriate
to provide a viscosity measurement it will enable determination of
an increase in viscosity brought about by the polymer.
[0075] An additional or alternative characterisation of a suitable
polymer is that it can thicken the water-immiscible liquid to a
viscosity of at least 10,000 mPa.sec, measured in the same way,
when incorporated in the water-immiscible liquid at not more than
6% by weight, in the absence of the other structurant.
[0076] The polymer will generally be solid at 20.degree. C.
[0077] One category of polymer which has been found suitable is a
polysaccharide esterified with a monocarboxylic acid containing at
least 8 carbon atoms.
[0078] Preferred in this category is a dextrin fatty acid ester
having the formula: 1
[0079] wherein each R group, individually, is a hydrogen or an acyl
group of up to 22 carbon atoms, provided that at least one R group
per glucose unit is an acyl group of 8 to 22 carbon atoms, and m
has a value from about 20 to 30. The dextrin fatty acid ester can
be a partial ester, i.e. at least one R group is hydrogen. Another
possibility is that the dextrin can be completely esterified with
C.sub.8 to C.sub.22 acyl groups, i.e. every R group is a
C.sub.8-C.sub.22 acyl group. In preferred embodiments, the degree
of substitution with an R group which is a C.sub.8-C.sub.22 alkyl
group is at least 2 (i.e., at least two R groups are
C.sub.8-C.sub.22 acyl groups). A further possibility would be that
some R groups are acyl groups of less than 8 carbon atoms while
some R groups (at least one per glucose residue, preferably at
least two) is a C.sub.8 to C.sub.22 acyl group. The
C.sub.8-C.sub.22 fatty acids that provide acyl groups can be
saturated or unsaturated acids, and include, for example, capric
acid, pelargonic acid, caprylic acid, undecylic acid, undecylenic
acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid,
heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid,
oleic acid, linoleic acid, linolenic acid, similar acids, and
mixtures thereof. Dextrin fatty acid esters are disclosed in Mori
et al U.S. Pat. No. 4,780,145, incorporated herein by reference,
and some of them are available under the trade name RHEOPEARL from
Chiba Flour Milling Co., Ltd., Japan. An example of a dextrin fatty
acid ester is dextrin palmitate, available commercially as
RHEOPEARL KL and RHEOPEARL FL, for example, from Chiba Flour
Milling Co., Ltd. Other examples of esters of C.sub.8-C.sub.22
carboxylic acids are dextrin behenate, dextrin laurate, dextrin
myristate, dextrin stearate, and mixtures thereof.
[0080] Another type of polymer found to be suitable, although not
preferred, is alkyl substituted galactomannan available from
Hercules under their trade name N-HANCE AG.
[0081] Alternative organic polymer thickening agents comprise block
copolymers of styrene with an alkylene containing up to 5 carbons
being a mono or diene, or mixtures thereof, such as ethylene,
propylene, butylene and isoprene. Tri-block copolymers are
especially desirable, including SEBS copolymers.
[0082] Fibre-forming Structurant
[0083] A number of organic compounds are known to possess the
ability to gel hydrophobic organic liquids such as water-immiscible
hydrocarbon and/or silicone oils. Such materials are generally
monomers or dimers with molecular weight below 10,000 often below
5,000 rather than polymers with more than five repeat units or with
molecular weight above 10,000.
[0084] Gel formation takes place as an exothermic event within a
temperature range referred to as the gel point; upon reheating,
melting of the gel takes place as an endothermic event within a
temperature range. Such gels can be disrupted by shearing. Although
a small partial recovery may then be observed, such gels do not
recover their structure for a long time, if at all, unless
remelted.
[0085] Materials with this property have been reviewed by Terech
and Weiss in "Low Molecular Mass Gelators of Organic Liquids and
the Properties of their Gels" Chem. Rev 97, 3133-3159 [1997] and by
Terech in Chapter 8, "Low-molecular weight Organogelators" of the
book "Specialist surfactants" edited by I D Robb, Blackie Academic
Professional, 1997.
[0086] It is characteristic of such structurants, useful in this
invention, that
[0087] they are able to gel the organic liquid in the absence of
any disperse phase
[0088] the structured liquids are obtainable by cooling from an
elevated temperature at which the structurant is in solution in the
liquid--this solution being mobile and pourable
[0089] the structured liquid becomes more mobile if subjected to
shear or stress
[0090] the structure does not spontaneously recover within 24 hours
if the sheared liquid is left to stand at ambient laboratory
temperature, even though a small partial recovery may be
observed
[0091] the structure can be recovered by reheating to a temperature
at which the structurant is in solution in the liquid and allowing
it to cool back to ambient laboratory temperature.
[0092] It appears that such structurants operate by interactions
which are permanent unless disrupted by shear or heating. Such
structurants form a network of strands or fibres extending
throughout the gelled liquid. In some cases these fibres can be
observed by electron microscopy, although in other cases the
observation of the fibres which are believed to be present is
prevented by practical difficulties in preparing a suitable
specimen. When observed, the primary fibres in a gel are generally
thin (diameter less than 0.5.mu., often less than 0.2.mu.) and
appear to have numerous branches or interconnections. Primary
fibres may entwine to form a thicker strand.
[0093] If these fibres are crystalline, they may or may not be the
same polymorph as macroscopic crystals obtained by conventional
crystallization from a solvent.
[0094] One material which is well known to form such gels is
12-hydroxy stearic acid which is discussed in Terech et al
"Organogels and Aerogels of Racemic and Chiral 12-hydroxy
octadecanoic Acid", Langmuir Vol 10, 3406-3418, 1994. The material
is commercially available from Ajinomoto and also from Caschem.
U.S. Pat. No. 5,750,096 is one of several documents which teaches
that gelation can be brought about using esters or amides of
12-hydroxy stearic acid. The alcohol used to form such an ester or
the amine used to form such an amide may contain an aliphatic,
cycloaliphatic or aromatic group with up to 22 carbons therein. If
the group is aliphatic it preferably contains at least three carbon
atoms. A cycloaliphatic group preferably contains at least five
carbon atoms and may be a fixed ring system such as adamantyl.
[0095] Other fatty acids with C.sub.8 or longer alkyl chains may be
used and amides thereof can also be used. A specific example is
lauric monoethanolamide also termed MEA lauramide.
[0096] N-acyl amino acid amides and esters are also known to
structure liquids. We have established that they do so by forming
fibrous networks. They are described in U.S. Pat. No. 3,969,087.
N-Lauroyl-L-glutamic acid di-n-butylamide is commercially available
from Ajinomoto under their designation GP-1.
[0097] Further materials which have been disclosed as gelling
agents are the amide derivatives of di and tribasic carboxylic
acids set forth in WO 98/27954 notably alkyl N,N'dialkyl
succinamides.
[0098] Lanosterol, as disclosed in U.S. Pat. No. 5,635,165 may
suitably be used if the water-immiscible liquid is silicone oil and
provided the polymeric thickener is sufficiently soluble
therein.
[0099] Lanosterol has the following chemical formula: 2
[0100] It is commercially available, eg from Croda Chemicals Ltd,
and as supplied it contains some dihydrolanosterol. This impurity
in the commercial material does not need to be removed.
[0101] A novel structurant which is the subject of a co-pending
application is a combination of a sterol and a sterol ester.
[0102] In its preferred form the sterol satisfies either of the two
formulae: 3
[0103] in which R represents an aliphatic, cycloaliphatic or
aromatic group, and preferably a linear or branched aliphatic
saturated or unsaturated hydrocarbon group. R desirably contains
from I to 20 carbons and preferably from 4 to 14 carbons.
[0104] It is particularly suitable to employ .beta. sitosterol or
campesterol or cholesterol, or a hydrogenated derivative thereof,
such as dihydrocholesterol, or a mixture of two or more of them. An
especially preferred sterol is .beta.-sitosterol.
[0105] The preferred sterol ester is oryzanol, sometimes referred
to as .gamma.-oryzanol which contains material satisfying the
following formula: 4
[0106] The sterol and sterol ester are used in a mole ratio that is
normally selected in the range of from 10:1 to 1:10, especially
from 6:1 to 1:4 and preferably in the range of from 3:1 to 1:2.
Employment of the two system constituents within such a mole ratio
range, and especially within the preferred range facilitates the
co-stacking of the constituents and consequently facilitates the
formation of a network that is readily able to structure the
formulation.
[0107] Another novel structurant which is the subject of a
co-pending application and which may be used in this invention is
an ester of cellobiose and a fatty acid, preferably of 6 to 13
carbon atoms especially 8 to 10 carbon atoms. Preferably the
cellobiose is fully esterified, or nearly so, and is in the
.alpha.-anomeric form. 5
[0108] The structure of such a compound, in its .alpha.-anomeric
form is: where R is an alkyl or alkenyl chain of 5 to 12 carbon
atoms so that the acyl group contains 6 to 13 carbon atoms.
Particularly preferred acyl groups incorporate a linear alkyl chain
of 7 to 10 carbon atoms and are thus octanoyl, nonanoyl, decanoyl
or undecanoyl.
[0109] The acyl groups may have a mixture of chain lengths but it
is preferred that they are similar in size and structure. Thus it
is preferred that all of the acyl groups are aliphatic and at least
90% of the acyl groups have a chain length within a range such that
the shorter and longer chain lengths in the range differ by no more
than two carbon atoms, i.e. length in a range from m-1 to m+1
carbon atoms where m has a value in a range from 7 to 10.
[0110] Linear aliphatic acyl groups may be obtained from natural
sources, in which case the number of carbon atoms in the acyl group
is likely to be an even number or may be derived synthetically from
petroleum as the raw material in which case both odd an even
numbered chain lengths are available. Synthetic methods for the
esterification of saccharides are well known. The esterification of
cellobiose has been reported by Takada et al in Liquid Crystals,
(1995) Volume 19, pages 441-448. This article gives a procedure for
the production of the alpha anomers of cellobiose octa-alkanoates
by esterification of .beta.-cellobiose using an alkanoic acid
together with trifluoracetic anhydride.
[0111] A further example of structurant which is the subject of a
co-pending application is compounds of the following general
structure (I): 6
[0112] It is preferred that m is 2 so that the structurant
compounds comply with a general formula (T1): 7
[0113] The groups Y and Y.sup.1 will usually be identical, i.e.
both methylene or both carbonyl. The groups Q and Q.sup.1 may not
be the same but often will be identical to each other.
[0114] If m is 2 and Y and Y.sup.1 are methylene groups, the
compound is a derivative of threitol, which is
1,2,3,4-tetrahydroxybutane, while if m is 2 and Y and Y.sup.1 are
carbonyl groups, the compound is a diester of tartartic acid, which
is 2,3-dihydroxybutane-1,4-dioic acid.
[0115] It is preferred that each group Q and Q.sup.1 contains an
aromatic nucleus which may be phenyl or, less preferably, some
other aromatic group. Thus Q and Q.sup.1 may be groups of the
formula:
Ar--(CH.sub.2)n--
[0116] where Ar denotes an aromatic nucleus, notably phenyl or
substituted phenyl and n is from 0 to 10.
[0117] An aromatic nucleus (Ar) is preferably unsubstituted or
substituted with one or more substituents selected from alkyl,
alkyloxy, hydroxy, halogen or nitro. One substituent may be an
alkyl or alkyloxy group with a long alkyl chain. Thus a formula
(T2) for preferred structurants of this invention can be given as:
8
[0118] where
[0119] n=0 to 10, preferably 0 to 3, more preferably 1, 2 or 3;
[0120] Y=--CH.sub.2-- or >C=O
[0121] X.sub.1=H, C1, Br, F, OH, NO.sub.2, O--R, or R, where R is
an aliphatic hydrocarbon chain with 1 to 18 carbon atoms.
[0122] X.sub.2 to X.sub.5 are each independently H, C1, Br, F, OH,
NO.sub.2, OCH.sub.3, or CH.sub.3
[0123] In these formulae above, the central carbon atoms which bear
hydroxy groups are chiral centres. Thus if m=2, Y and Y.sup.1 are
the same and Q and Q.sup.1 are the same, the compounds will exist
as R,R and S,S optically active forms as well as an optically
inactive R,S form.
[0124] These compounds may be used as their optically active R,R or
S,S forms or as a mixture of the two--which may be a racemic
mixture.
[0125] Compounds within the general formulae (T1 and T2) above are
available commercially. Also, syntheses of these compounds have
been given in scientific literature where the compounds were being
used as intermediates for purposes not related to the present
invention. Thus syntheses of threitol derivatives can be found
in:
[0126] Kataky et al, J. Chem Soc Perkin Trans vol 2 page 321
[1990]
[0127] Tamoto et al, Tetrahedron Vol 40 page 4617 [1984], and
[0128] Curtis et al, J.C.S. Perkin I Vol 15 page 1756 [1977].
[0129] Preparations of tartrate esters are found at:
[0130] Hu et al J. Am. Chem. Soc. Vol 118, 4550 [1996] and
[0131] Bishop et al J. Org Chem Vol56 5079 [1991].
[0132] Amounts of Structurant and Polymer
[0133] As already mentioned the amount of fibre-forming structurant
is preferably enough to gel the water-immiscible liquid to a
shape-sustaining form, even without polymer. The amount of polymer
will preferably be enough to thicken the liquid to a viscous state
in the absence of fibre-forming structurant.
[0134] The amount of fibre-forming structurant will usually be at
least 2% or 3%, more preferably at least 5% by weight of the
composition. The amount of polymeric thickener will usually be at
least 0.2%, in many instances at least 0.3% and often at least 0.5%
or 1% by weight of the composition.
[0135] The amount of fibre-forming structurant may lie in a range
up to 10% more preferably not above 8% by weight of the
composition. In other formulations according to the present
invention, the amount of fibre-forming structurant may lie in a
range up to 15%, such as from 10 to 12% by weight of the
composition.
[0136] The amount of polymeric thickener may be up to 15% by weight
but preferably the polymer is sufficiently effective as a thickener
that amounts up to 10% are sufficient. Suitable amounts of
polymeric thickener which is one or more polysaccharides esterified
with a monocarboxylic acid of 8 to 22 carbon atoms may be in the
range from 0.5 to 1% up to 5% or 6% by weight of the
composition.
[0137] The total amount of the fibre-forming structurant and
polymeric thickener will often lie in a range from 3% or 4% by
weight of the composition up to 12%, 15%, 16% or 18%.
[0138] The percentage by weight of fibre-forming structurant will
generally be greater than the percentage by weight of polymer. In
many formulations, the weight ratio of the fibre-forming
structurant to the polymeric thickener will be at least 2:1 and in
many formulations at least 5:1. Commonly, this weight ratio is not
more than 40:1 and in many formulations is up to 30:1. In
formulations containing a dextrin fatty acid ester, the ratio is
often from 5:1 to 20:1 and in formulations containing a block
copolymer as described hereinabove, the ratio is often from 10:1 to
30:1.
[0139] Liquid Disperse Phase
[0140] If the composition is an emulsion, it will contain a
solution of an active ingredient as a liquid disperse phase. The
disperse phase in an emulsion is hydrophilic. It normally comprises
water as solvent and can comprise one or more water soluble or
water miscible liquids in addition to or replacement for water. The
proportion of water in an emulsion embodying the present invention
is often selected in the range of up to 60%, and particularly from
10% up to 40% or 50% of the whole formulation.
[0141] One class of water soluble or water-miscible liquids
comprises short chain monohydric alcohols, e.g. C.sub.1 to C.sub.4
and especially ethanol or isopropanol, which can impart a
deodorising capability to the formulation. A further class of
hydrophilic liquids comprises diols or polyols preferably having a
melting point of below 40.degree. C., or which are water miscible.
Examples of water-soluble or water-miscible liquids with at least
one free hydroxy group include ethylene glycol, 1,2-propylene
glycol, 1,3-butylene glycol, hexylene glycol, diethylene glycol,
dipropylene glycol, 2-ethoxyethanol, diethylene glycol
monomethylether, triethyleneglycol monomethylether and sorbitol.
Especially preferred are propylene glycol and glycerol.
[0142] In an emulsion the disperse phase is likely to constitute
from 5 to 80 or 85% of the weight of the composition preferably
from 5 to 50 or 65% more preferably from 25 or 35% up to 50 or 65%,
while the continuous phase with the structurant therein provides
the balance from 15 or 35% up to 95% of the weight of the
composition. Compositions with high proportion of disperse phase,
i.e. from 65 to 85% disperse phase, may also be advantageous. They
can give good hardness even though the structured continuous phase
is only a small percentage of the total composition.
[0143] An emulsion composition will generally include one or more
emulsifying surfactants which may be anionic, cationic,
zwitterionic and/or nonionic surfactants. The proportion of
emulsifier in the composition is often selected in the range up to
10% by weight and in many instances from 0.1 or 0.25 up to 5% by
weight of the composition. Most preferred is an amount from 0.1 or
0.25 up to 3% by weight. Nonionic emulsifiers are frequently
classified by HLB value. It is desirable to use an emulsifier or a
mixture of emulsifiers with an overall HLB value in a range from 2
to 10 preferably from 3 to 8.
[0144] It may be convenient to use a combination of two or more
emulsifiers which have different HLB values above and below the
desired value. By employing the two emulsifiers together in
appropriate ratio, it is readily feasible to attain a weighted
average HLB value that promotes the formation of an emulsion.
[0145] Many suitable emulsifiers of high HLB are nonionic ester or
ether emulsifiers comprising a polyoxyalkylene moiety, especially a
polyoxyethylene moiety, often containing from about 2 to 80, and
especially 5 to 60 oxyethylene units, and/or contain a polyhydroxy
compound such as glycerol or sorbitol or other alditol as
hydrophilic moiety. The hydrophilic moiety can contain
polyoxypropylene. The emulsifiers additionally contain a
hydrophobic alkyl, alkenyl or aralkyl moiety, normally containing
from about 8 to 50 carbons and particularly from 10 to 30 carbons.
The hydrophobic moiety can be either linear or branched and is
often saturated, though it can be unsaturated, and is optionally
fluorinated. The hydrophobic moiety can comprise a mixture of chain
lengths, for example those deriving from tallow, lard, palm oil,
sunflower seed oil or soya bean oil. Such nonionic surfactants can
also be derived from a polyhydroxy compound such as glycerol or
sorbitol or other alditols. Examples of emulsifiers include
ceteareth-10 to -25, ceteth-10-25, steareth-10-25 (i.e. C.sub.16 to
C.sub.18 alcohols ethoxylated with 10 to 25 ethylene oxide
residues) and PEG-15-25 stearate or distearate. Other suitable
examples include C.sub.10-C.sub.20 fatty acid mono, di or
tri-glycerides. Further examples include C.sub.18-C.sub.22 fatty
alcohol ethers of polyethylene oxides (8 to 12 EO).
[0146] Examples of emulsifiers, which typically have a low HLB
value, often a value from 2 to 6 are fatty acid mono or possibly
diesters of polyhydric alcohols such as glycerol, sorbitol,
erythritol or trimethylolpropane. The fatty acyl moiety is often
from C.sub.14 to C.sub.22 and is saturated in many instances,
including cetyl, stearyl, arachidyl and behenyl. Examples include
monoglycerides of palmitic or stearic acid, sorbitol mono or
diesters of myristic, palmitic or stearic acid, and
trimethylolpropane monoesters of stearic acid.
[0147] A particularly desirable class of emulsifiers comprises
dimethicone copolymers, namely polyoxyalkylene modified
dimethylpolysiloxanes. The polyoxyalkylene group is often a
polyoxyethylene (POE) or polyoxypropylene (POP) or a copolymer of
POE and POP. The copolymers often terminate in C.sub.1 to C.sub.12
alkyl groups.
[0148] Suitable emulsifiers and co-emulsifiers are widely available
under many trade names and designations including Abil.TM.,
Arlace.TM., Brij.TM., Cremophor.TM., Dehydrol.TM., Dehymuls.TM.,
Emerest.TM., Lameform.TM., Pluronic.TM., Prisorine.TM., Quest
PGPH.TM., Span.TM., Tween.TM., SF1228, DC3225C and Q2-5200.
[0149] Antiperspirant Actives
[0150] Antiperspirant actives for use herein are often selected
from astringent active salts, including in particular aluminium,
zirconium and mixed aluminium/zirconium salts, including both
inorganic salts, salts with organic anions and complexes. Preferred
astringent salts include aluminium, zirconium and
aluminium/zirconium halides and halohydrate salts, such as
chlorohydrates.
[0151] Aluminium halohydrates are usually defined by the general
formula Al.sub.2(OH).sub.xQ.sub.y.wH.sub.2O in which Q represents
chlorine, bromine or iodine, x is variable from 2 to 5 and x+y=6
while wH.sub.2O represents a variable amount of hydration.
Especially effective aluminium halohydrate salts, known as
activated aluminium chlorohydrates, are described in EP-A-6739
(Unilever NV et al), the contents of which specification is
incorporated herein by reference. Some activated salts do not
retain their enhanced activity in the presence of water but are
useful in substantially anhydrous formulations, i.e. formulations
which do not contain a distinct aqueous phase.
[0152] Zirconium actives can usually be represented by the
empirical general formula: ZrO(OH).sub.2n-nxB.sub.z.wH.sub.2O in
which z is a variable in the range of from 0.9 to 2.0 so that the
value 2n-nz is zero or positive, n is the valency of B, and B is
selected from the group consisting of chloride, other halide,
sulphamate, sulphate and mixtures thereof. Possible hydration to a
variable extent is represented by wH.sub.2O. Preferable is that B
represents chloride and the variable z lies in the range from 1.5
to 1.87. In practice, such zirconium salts are usually not employed
by themselves, but as a component of a combined aluminium and
zirconium-based antiperspirant.
[0153] The above aluminium and zirconium salts may have coordinated
and/or bound water in various quantities and/or may be present as
polymeric species, mixtures or complexes. In particular, zirconium
hydroxy salts often represent a range of salts having various
amounts of the hydroxy group. Zirconium aluminium chlorohydrate may
be particularly preferred.
[0154] Antiperspirant complexes based on the above-mentioned
astringent aluminium and/or zirconium salts can be employed. The
complex often employs a compound with a carboxylate group, and
advantageously this is an amino acid. Examples of suitable amino
acids include dl-tryptophan, dl-.beta.-phenylalanine, dl-valine,
dl-methionine and .beta.-alanine, and preferably glycine which has
the formula CH.sub.2(NH.sub.2)COOH.
[0155] It is highly desirable to employ complexes of a combination
of aluminium halohydrates and zirconium chlorohydrates together
with amino acids such as glycine, which are disclosed in U.S. Pat.
No. 3,792,068 (Luedders et al). Certain of those Al/Zr complexes
are commonly called ZAG in the literature. ZAG actives generally
contain aluminium, zirconium and chloride with an Al/Zr ratio in a
range from 2 to 10, especially 2 to 6, an Al/Cl ratio from 2.1 to
0.9 and a variable amount of glycine. Actives of this preferred
type are available from Westwood, from Summit and from Reheis.
[0156] Other actives which may be utilised include astringent
titanium salts, for example those described in GB 2299506A.
[0157] The weight of solid antiperspirant salt in a composition
which is a suspension of particulate solid normally includes the
weight of any water of hydration and any complexing agent that may
also be present in the solid active.
[0158] In a composition in which antiperspirant active in
particulate form is suspended in the water-immiscible liquid
carrier, the particle size of the antiperspirant salts often falls
within the range of 0.1 to 200 .mu.m with a mean particle size
often from 3 to 20 .mu.m. Both larger and smaller mean particle
sizes can also be contemplated such as from 20 to 50 .mu.m or 0.1
to 1 .mu.m or up to 3 .mu.m.
[0159] If the composition is in the form of an emulsion the
antiperspirant active will be dissolved in the disperse phase and
the weight of antiperspirant active in the composition is taken as
the weight of solid active salt excluding any water or solvent
present. In this case, the antiperspirant active will often provide
from 3 to 60% by weight of the disperse phase, particularly from
10% or 20% up to 55% or 60% of that phase.
[0160] Optional Ingredients
[0161] Optional ingredients in compositions of this invention can
include disinfectants, for example at a concentration of up to
about 10% w/w. Suitable deodorant actives can comprise deodorant
effective concentrations of antiperspirant metal salts,
deoperfumes, and/or microbicides, including particularly
bactericides, such as chlorinated aromatics, including biguanide
derivatives, of which materials known as Igasan DP300.TM.,
Triclosan, Tricloban.TM., and Chlorhexidine warrant specific
mention. A yet another class comprises biguanide salts such as
available under the trade mark Cosmosil.TM..
[0162] Other optional ingredients include wash-off agents, often
present in an amount of up to 10% w/w to assist in the removal of
the formulation from skin or clothing. Such wash-off agents are
typically nonionic surfactants such as esters or ethers containing
a C.sub.8 to C.sub.22 alkyl moiety and a hydrophilic moiety which
can comprise a polyoxyalkylene group (POE or POP) and/or a polyol.
A possible optional ingredient is a wax, as defined earlier,
desirably in a small amount not exceeding 3% by weight of the
composition.
[0163] The compositions herein can incorporate one or more cosmetic
adjuncts conventionally envisaged for antiperspirant soft solids.
Such cosmetic adjuncts can include skin feel improvers, such as
talc or finely divided polyethylene, for example in an amount of up
to about 10%; skin benefit agents such as allantoin or lipids, for
example in an amount of up to 5%; colours; skin cooling agents
other than the already mentioned alcohols, such a menthol and
menthol derivatives, often in an amount of up to 2%, all of these
percentages being by weight of the composition. A commonly employed
adjunct is a perfume, which is normally present at a concentration
of from 0 to 4% and in many formulations from 0.25 to 2% by weight
of the composition.
[0164] Ethanol gives a cooling effect on application to skin,
because it is very volatile. It is preferred that the content of
ethanol or any monohydric alcohol with a vapour pressure above 1.3
kPa (10 mmHg) is not over 15% better not over 8% by weight of the
composition.
[0165] Translucent/Transparent Compositions
[0166] If a composition of this invention is formulated as an
emulsion it is possible to construct the formulation such that the
emulsion is translucent or transparent. In order to do this the
refractive indices of the water-immiscible continuous phase and the
polar or aqueous disperse phase must be matched to each other and
the value of refractive index at which they are matched must also
approximately match the refractive index of the fibre-forming
structurant.
[0167] The refractive index of a fibrous network of a structurant
can be determined by using that structurant to gel a number of oils
or oil mixtures of differing refractive index. When the resulting
gel is transparent, the refractive index of the oil or oil
mixture(which can be determined by conventional measurement) is a
good approximation to the refractive index of the structurant. The
oils or mixtures of oils should be chosen from those which are
gelled well by the structurant to avoid interfering effects.
[0168] Some examples of oils which may be used to make mixtures
which vary in refractive index and used for the purpose of such
measurement are:
[0169] volatile silicone (refractive index about 1.40)
[0170] C.sub.12-15 alkyl benzoate (refractive index about 1.48)
which is available as Finsolv TN and/or
[0171] octylmethoxycinnamate (refractive index about 1.54) which is
available as Parsol MCX
[0172] Polyphenylsiloxane (DC710) (refractive index about
1.53).
[0173] Cinnamic aldehyde (refractive index about 1.62).
[0174] Using this method we have determined the refractive indices
of some structurants, namely:
[0175] N-lauroyl L-glutamic acid di-n-butylamide approx 1.48
[0176] 12-hydroxystearic acid approx 1.52
[0177] .alpha.-cellobiose octa-esters with C.sub.8 to C.sub.12
[0178] fatty acids approx 1.48
[0179] It appears that polymeric thickeners often cause little
scattering of light and do not generally need to be taken
separately into account for refractive index matching. For the
continuous phase, silicon-free water-immiscible liquid oils
generally have refractive indices in a range from 1.43 to 1.49 at
22.degree. C. and can be used alone or mixed together to give a
silicon-free carrier liquid with refractive index in this range.
Volatile silicone oils generally have a refractive index slightly
below 1.40 at 22.degree. C., but carrier liquid mixtures with
refractive indices in the range from 1.41 to 1.46 can be obtained
by mixing limited amounts of volatile silicone with other oils.
Cosmetically acceptable non-volatile silicone oils generally have
refractive indices in a range from 1.45 to 1.48 at 22.degree. C.
and so can be included when desired.
[0180] The refractive index of the continuous phase will be very
close to the refractive index of the carrier liquid (usually a
carrier liquid mixture) which is its principal component. The
polymeric thickener and any minor ingredients dissolved in the
carrier liquid will affect its refractive index, but their effect
will usually be small.
[0181] For the disperse phase, a solution of an antiperspirant
active salt in water alone will generally display a refractive
index below 1.425. The refractive index can be raised by
incorporating a diol or polyol into the aqueous solution.
[0182] For the regular production of compositions with optimum
transparency it may prove desirable to monitor the refractive
indices of the raw materials to detect any batch to batch
variation. If necessary the composition of a liquid phase can be
adjusted by variations in the quantity of a constituent
material.
[0183] For a composition which is a suspension the route to a
transparent or translucent composition is to match the refractive
indices of the liquid carrier and the suspended solid to that of
the fibre-forming structurant. Particulate antiperspirant actives
which are anhydrous solids generally have a refractive index
substantially above 1.50 which is brought down by hydration, but we
have found that it is not easy to obtain an antiperspirant active
with a refractive index of 1.48 or below even if the active is
partially hydrated to lower its refractive index. Therefore it is
possible, but more difficult, to match refractive indices within a
composition which is a suspension of particulate solid
antiperspirant active.
[0184] Although compositions of this invention may be translucent
or opaque when seen in bulk, they are nevertheless able to give a
low visible residue when applied to skin or transferred to
fabric.
[0185] Product Packages
[0186] A composition of this invention will usually be marketed as
a product comprising a container with a quantity of the composition
therein, where the container has at least one aperture for the
delivery of composition, and means for urging the composition in
the container towards the delivery aperture. Conventional
containers take the form of a barrel of oval cross section with the
delivery aperture(s) at one end of the barrel.
[0187] A composition of this invention is preferably sufficiently
rigid that it is not apparently deformable by hand pressure, even
though a surface layer will transfer as a film to skin, and is
suitable for use as a stick product in which a quantity of the
composition in the form of a stick is accommodated within a
container barrel having an open end at which an end portion of the
stick of composition is exposed for use. The opposite end of the
barrel is closed.
[0188] Generally the container will include a cap for its open end
and a component part which is sometimes referred to as an elevator
or piston fitting within the barrel and capable of relative axial
movement along it. The stick of composition is accommodated in the
barrel between the piston and the open end of the barrel. The
piston is used to urge the stick of composition along the barrel.
The piston and stick of composition may be moved axially along the
barrel by manual pressure on the underside of the piston using a
finger or rod inserted within the barrel. Another possibility is
that a rod attached to the piston projects through a slot or slots
in the barrel and is used to move the piston and stick. Preferably
the container also includes a transport mechanism for moving the
piston comprising a threaded rod which extends axially into the
stick through a correspondingly threaded aperture in the piston,
and means mounted on the barrel for rotating the rod. Conveniently
the rod is rotated by means of a handwheel mounted on the barrel at
its closed end, i.e. the opposite end to the delivery opening.
[0189] The component parts of such containers are often made from
thermoplastic materials, for example polypropylene or polyethylene.
Descriptions of suitable containers, some of which include further
features, are found in U.S. Pat. Nos. 4,865,231, 5,000,356 and
5,573,341.
[0190] Preparation
[0191] Compositions of this invention can be produced by
conventional processes. Such processes involve forming a heated
mixture of the composition at a temperature which is sufficiently
elevated that all the polymeric thickener and gelating structurant
dissolves, introducing antiperspirant active, then pouring or
otherwise introducing that mixture into a mould, which may be a
dispensing container, and then cooling the mixture.
[0192] A convenient process sequence for a composition which is a
suspension comprises first forming a solution of the polymer and
other structurant in the water-immiscible liquid or liquid mixture.
This is normally carried out by agitating the mixture at a
temperature sufficiently high that all the structurant dissolves
(the dissolution temperature) such as a temperature in a range from
50 to 120.degree. C. Thereafter the particulate constituent, for
example particulate antiperspirant active, is blended with the hot
mixture. This must be done slowly, or the particulate solid must be
preheated, in order to avoid premature gelation. The resulting
blend is then introduced into a dispensing container such as a
stick barrel. This is usually carried out at a temperature 5 to
30.degree. C. above the setting temperature of the composition. The
container and contents are then cooled to ambient temperature.
Cooling may be brought about by nothing more than allowing the
container and contents to cool. Cooling may be assisted by blowing
ambient or even refrigerated air over the containers and their
contents.
[0193] In a suitable procedure for making emulsion formulations, a
solution of the structurant in the water-immiscible liquid phase is
prepared at an elevated temperature just as for suspension sticks.
If any emulsifier is being used, this is conveniently mixed into
this liquid phase. Separately an aqueous or hydrophilic disperse
phase is prepared by introduction of antiperspirant active into the
liquid part of that phase (if this is necessary: antiperspirant
actives can sometime be supplied in aqueous solution which can be
utilised as is). If possible, this solution of antiperspirant
active which will become the disperse phase is preferably heated to
a temperature similar to that of the continuous phase with
structurant therein, but without exceeding the boiling point of the
solution, and then mixed with the continuous phase. Alternatively,
the solution is introduced at a rate which maintains the
temperature of the mixture. If it is necessary to work at a
temperature above the boiling temperature of the disperse phase, or
at a temperature where evaporation from this phase is significant,
a pressurised apparatus could be used to allow a higher temperature
to be reached. With the structurant materials of this invention
this is usually unnecessary. After the two phases are mixed, the
resulting mixture is filled into dispensing containers, typically
at a temperature 5 to 30.degree. C. above the setting temperature
of the composition, and allowed to cool as described above for
suspension sticks.
[0194] Measurement of Properties
[0195] i) Penetrometer
[0196] The hardness and rigidity of a composition which is a firm
solid can be determined by penetrometry. If the composition is a
softer solid, this will be observed as a substantial lack of any
resistance to the penetrometer probe.
[0197] A suitable procedure is to utilises a lab plant PNT
penetrometer equipped with a Seta wax needle (weight 2.5 grams)
which has a cone angle at the point of the needle specified to be
9.degree.10'.+-.15'. A sample of the composition with a flat upper
surface is used. The needle is lowered onto the surface of the
composition and then a penetration hardness measurement is
conducted by allowing the needle with its holder to drop under a
total weight, (i.e. the combined weight of needle and holder) of 50
grams for a period of five seconds after which the depth of
penetration is noted.
[0198] Desirably the test is carried out at a number of points on
each sample and the results are averaged. Utilising a test of this
nature, an appropriate hardness for use in an open-ended dispensing
container is a penetration of less than 30 mm in this test, for
example in a range from 2 to 30 mm. Preferably the penetration is
in a range from 5 mm to 20 mm. A penetration of no more than 30 mm
better no more than 20 mm in this test may be taken as
characteristic of a firm composition.
[0199] It is preferred that if the polymeric thickener is omitted
from the composition, so that it is structured by the fibre-forming
gelating structurant, the penetration in this test is not more than
30 mm.
[0200] A test composition consisting of the water-immiscible liquid
and the fibre-forming gelating structurant only, in the same
proportions as in a complete composition of this invention, may
display a penetration of no more than 30 mm in this test. In a
specific protocol for this test, a test composition was prepared as
a stick, and measurements on a stick were performed in the stick
barrel. The stick was wound up to project from the open end of the
barrel, and then cut off to leave a flat, uniform surface. The
needle was carefully lowered to the stick surface, and then a
penetration hardness measurement was conducted. This process was
carried out at six different points on the stick surface. The
hardness reading quoted is the average value of the 6
measurements.
[0201] ii) Deposition
[0202] Another test of the properties of a composition is the
amount of the composition which is delivered onto a surface when
the composition is drawn across that surface (representing the
application of a stick product to human skin). To carry out this
test of deposition, a sample of the composition with standardised
shape and size is fitted to apparatus which draws the sample across
a test surface under standardised conditions. The amount
transferred to the surface is determined as an increase in the
weight of the substrate to which it is applied. If desired the
colour, opacity or clarity of the deposit may subsequently be
determined.
[0203] A specific procedure for such tests used apparatus to apply
a deposit from a stick onto a substrate under standardised
conditions and then measures the mean level of white deposits using
image analysis.
[0204] The substrates used were:
[0205] a: 12.times.28 cm strip of grey abrasive paper (3M.TM. P800
WetorDry.TM. Carborundum paper)
[0206] b: 12.times.28 cm strip of black Worsted wool fabric.
[0207] The substrates were weighed before use. The sticks were
previously unused and with domed top surface unaltered.
[0208] The apparatus comprised a flat base to which a flat
substrate was attached by a clip at each end. A pillar having a
mounting to receive a standard size stick barrel was mounted on an
arm that was moveable horizontally across the substrate by means of
a pneumatic piston.
[0209] Each stick was kept at ambient laboratory temperature
overnight before the measurement was made. The stick was advanced
to project a measured amount from the barrel. The barrel was then
placed in the apparatus and a spring was positioned to biassed the
stick against the substrate with a standardised force. The
apparatus was operated to pass the stick laterally across the
substrate eight times. The substrate was carefully removed from the
rig and reweighed.
[0210] iii) Whiteness of Deposit
[0211] The deposits from the previous test were assessed for their
whiteness after an interval of 24 hours approximately. This was
done using a Sony XC77 monochrome video camera with a Cosmicar 16
mm focal length lens positioned vertically above a black table
illuminated from a high angle using fluorescent tubes to remove
shadowing. The apparatus was initially calibrated using a reference
grey card, after the fluorescent tubes had been turned on for long
enough to give a steady light output. A cloth or Carborundum paper
with a deposit thereon from the previous test was placed on the
table and the camera was used to capture an image. An area of the
image of the deposit was selected and analysed using a Kontron IBAS
image analyser. This notionally divided the image into a large
array of pixels and measured the grey level of each pixel on a
scale of 0 (black) to 255 (white). The average of the grey
intensity was calculated. This was a measure of the whiteness of
the deposit, with higher numbers indicating a whiter deposit. It
was assumed that low numbers show a clear deposit allowing the
substrate colour to be seen.
[0212] iv) Light transmission
[0213] The translucency of a composition may be measured by placing
a sample of standardised thickness in the light path of a
spectrophotometer and measuring transmittance, as a percentage of
light transmitted in the absence of the gel.
[0214] We have carried out this test using a dual-beam
spectrophotometer. The sample of composition was poured hot into a
4.5 ml cuvette made of polymethylmethacrylate (PMMA) and allowed to
cool to an ambient temperature of 20-25.degree. C. Such a cuvette
gives a 1 cm thickness of composition. Measurement was carried out
at 580 nm, with an identical but empty cuvette in the reference
beam of the spectrophotometer, after the sample in the cuvette had
been held for 24 hours. We have observed that a composition which
gives a transmittance of as little as 1% in this test is perceived
by eye as "translucent". If a stick is made from a composition with
3% transmittance, it is possible to see cavities made by boring
beneath the surface of the sample. By contrast, a conventional
stick structure with stearyl alcohol is so opaque that it is
impossible to see beneath its surface. A transmittance measured at
any temperature in the range from 20-25.degree. C. is usually
adequately accurate, but measurement is made at 22.degree. C. if
more precision is required.
EXAMPLES
[0215] The examples and comparative examples below were prepared
using a number of materials set out with their proprietary names in
the following list. All temperatures are in degrees Celsius.
[0216] 1) Volatile cyclic silicone (cyclomethicone) DC 245(Dow
Corning)
[0217] 2) Octyldodecanol (Eutanol G from Henkel)
[0218] 3) N-lauryl-L-glutamic acid di-n-butylamide (GP1 from
Ajiinomoto)
[0219] 4) Rheopearl KL from Chiba Flour Milling Co
[0220] 5) .beta.-sitosterol (available as ultrasitosterol from
Kaukas)
[0221] 6) .gamma.-oryzanol (from Jan Dekker (UK) Ltd)
[0222] 7) C12-15 alkyl benzoate (Finsolv TN from Fintex)
[0223] 8) Al/Zr tetrachlorohydrex glycine complex (WZR 30 DM HBD
from Westwood, also known as Westchlor 30B DM HBD)
[0224] 9) Al/Zr Tetrachlorohydrex glycine complex (AZAG 7167 from
Summit)
[0225] 10) Suprafino talc (particle size about 5.mu.) from Cyprus
Minerals
[0226] 11) 12-hydroxystearic acid from Caschem
[0227] 12) Panalene-L-14E (hydrogenated polyisobutene from
Amoco)
[0228] 13 Isopropyl myristate (abbreviated to IPM from
Unichema)
[0229] 14) Silicone wax (DC2503 from Dow Corning)
[0230] 15) Polydecene (Silkflo 364NF from Albemarle)
[0231] 16) 40% aqueous solution of Al/Zr pentachlorohydrate (Rezal
67 from Reheis)
[0232] 17) 50% aqueous solution of Al/Zr pentachlorohydrate
(Zirkonal 50 from Giulini)
[0233] 18) Cetyl dimethicone copolyol (Abil EM90 emulsifier from
Th. Goldschmidt)
[0234] 19) Polyglyceryl-3- diisostearate from Henkel
[0235] 20) Al/Zr tetrachlorohydrex glycine complex (Rezal 36GP-SUF
from Reheis)
[0236] 21) Thickening agent--block copolymer of styrene with
iso-prene (Kraton G1650 from Shell)
[0237] 22) Cellobiose octanonanoate--preparation following Example
1 of WO 00/61079.
[0238] Examples 1 to 3 and comparative Example 4 are all
antiperspirant suspension sticks prepared using a mixture of
water-immiscible liquids, an antiperspirant active, a fibre-forming
structurant compound or system and (for examples of the invention)
a thickening polymer.
[0239] The following general method of preparation was used for
these examples and comparative examples. A solution of the
thickening polymer (when employed) and other structurants in the
organic liquid(s) was made by mixing these materials, heating and
agitating the mixture at a temperature sufficiently high that the
polymer and other structurants all dissolve. The mixture was then
allowed to cool to 80-85.degree. C. before the antiperspirant
active was added. The mixture was next allowed to cool to
5-20.degree. C. above its gelling temperature (determined in a
preliminary experiment) and poured into dispensing containers.
These were then left to cool to room temperature.
[0240] When GP-1 was used, it was dissolved in the hot liquid
mixture before the thickening polymer was added and dissolved. When
.beta.-sitosterol and oryzanol were used in combination as
structurant, the oryzanol was first dissolved in the hot liquid
mixture followed by addition and dissolution of the thickening
polymer, and .beta.-sitosterol. The sticks were tested by
penetrometer and for whiteness of deposits by the test procedures
given earlier.
1 1.1 compara- Examples tive 1.2 1.3 Parts by weight GP1 (3) 5 5 5
Dextrin Palmitate (4) 0 2 2 Cyclomethicone DC 245 (1) 55 53 51
Octyldodecanol (2) 13.25 13.25 13.25 Perfume 0.75 0.75 0.75 AZAG
(8) 26 26 26 Talc (10) 0 0 2 Properties penetration depth (mm) 9.2
7.2 4.9 Whiteness on grey paper (initial) 30 30 30 Whiteness on
grey paper after 24 hours 35 36 38 Whiteness on black wool
(initial) 33 31 26 Whiteness on black wool after 24 hours 87 90
72
[0241] 1.2 shows an increase in hardness compared to 1.1, without
detriment to visible residue. 1.3 shows the possibility of
additionally adding talc without detriment to visible residues.
2EXAMPLE 2 2.1 2.3 Examples Comp 2.2 Comp 2.4 Percent by weight
Beta Sitosterol (5) 2.4 2.4 2.4 2.4 Oryzanol (6) 3.6 3.6 3.6 3.6
Dextrin Palmitate (4) 0 1 0 2 Cyclomethicone DC 245 (1) 40.8 40.2
54.4 52.8 C.sub.12-15 Alkyl Benzoate (7) 27.2 26.8 13.6 13.2 AZAG
(Q5-7167) (9) 24 24 24 24 Talc (10) 2 2 2 2 PROPERTIES penetration
depth (mm) 9.7 7.4 20.4 6.7 Whiteness on grey paper (initial) 26.9
23.3 * 26.0 Whiteness on grey paper 24 hours after 26.2 32.3 * 25.7
deposition Whiteness on black wool (initial) 35.7 16.7 * 22.4
Whiteness on black wool 24 hours after 28.6 9.5 * 14.2 * = too soft
to measure/apply
[0242]
3 2.5 2.7 Examples Comp 2.6 Comp 2.8 Percent by weight Beta
Sitosterol (5) 2.4 2.4 1.6 1.6 Oryzanol (6) 3.6 3.6 2.4 2.4 Dextrin
Palmitate (4) 0 2 0 1 12-hydroxystearic acid (11) 0 0 6 6
Cyclomethicone DC 245 (1) 47.6 46.2 37.2 36.6 C.sub.12-15 Alkyl
Benzoate (7) 20.4 19.8 24.8 24.4 AZAG (Q5-7167) (9) 24 24 24 24
Talc (10) 2 2 2 2 PROPERTIES penetration depth (mm) 10.9 6.3 9.9
9.2 Whiteness on grey paper (initial) 24.1 27.0 23.2 24.5 Whiteness
on grey paper after 24 hours 28.1 26.7 15.3 32.2 Whiteness on black
wool (initial) 27.9 19.0 30.9 29.3 Whiteness on black wool after 24
hours 13.8 9.7 39.1 12.4
[0243] In all the formulations of Example 2 incorporation of
polymer increases hardness without increasing whiteness.
[0244] Examples 2.3 (comparative) and 2.4 were tested for stability
at 50.degree. C.--an accelerated test. The composition of Example
2.3 displayed syneresis after 1 day. The composition of Example 2.4
remained stable over 7 days.
4EXAMPLE 3 Examples 3.1 3.2 (comparative) Percent by weight Beta
Sitosterol (5) 2.4 3.1 Oryzanol (6) 3.6 3.1 Cyclomethicone DC 245
(1) 45.7 50.5 C.sub.12-15 Alkyl Benzoate (7) 19.6 19.3 AZAG
(Q5-7167) (9) 24 24 Dextrin Palmitate (4) 2 0 Talc (10) 2 0 Perfume
0.7 0 PROPERTIES penetration depth (mm) 5.9 12 Whiteness on grey
paper (initial) 31 Whiteness on grey paper after 24 hours 29
Whiteness on black wool (initial) 20 Whiteness on black wool after
24 hours 11
[0245] These two compositions gave sticks which were opaque.
[0246] The two compositions were used for a test of efficacy
carried out with a panel of volunteers in a heated environment.
During a preliminary preparation period all the panellists used an
alcoholic underarm product which is a deodorant but not an
antiperspirant. During the test period the panellists used a
standard dosage of the product on one underarm and a placebo on the
other. The test measurement was made in a room at 40.degree. C. and
40% relative humidity. After a period of 40 minutes each underarm
is dried and a pre-weighed absorbent cotton pad is placed in the
underarm region. Each panellist remains seated in the room for a
further 20 minute period after which the cotton pads are collected
and re-weighed. The antiperspirant efficacy (% sweat reduction) is
calculated as 1 ( W 2 - W 1 ) W 2 .times. 100 %
[0247] where W.sub.1 is the weight of sweat collected from
underarms treated with the test product and W.sub.2 is the weight
of sweat collected from underarm regions which have received no
treatment.
[0248] The results obtained were
5 Formulation 3.1 (invention): 60.6% Formulation 3.2 (comparative):
39.0%
[0249]
6COMPARATIVE EXAMPLE 4 Examples 4.1 4.2 4.3 Percent by weight
DC2503 (14) 1 0 0 12-hydroxystearic acid (11) 8 8 9 Cyclomethicone
DC 245 (1) 47.0 47.7 47.0 Panalene-L-14E (12) 9.6 9.7 9.6 Isopropyl
myristate (13) 14.4 14.6 14.4 AlZr trichlorohydrex gly (8) 20 20 20
Properties Penetration depth (mm) 14.7 11.1 12.1 Whiteness on black
wool after 24 hours 27.5 26.5
[0250] It should be noted that the temperatures for pouring into
stick barrels were 2.degree. C. above temperatures at which
gelation had been found to occur in an initial trial experiment.
The temperatures were close to the range of 60-62.degree. C. taught
in U.S. Pat. No. 5,480,637--Example 15. The penetration depth for
Example 4.1 was greater than for Examples 4.2 or 4.3, indicating
that the incorporation of the DC 2503 silicone wax did not improve
hardness.
Example 5
[0251] Emulsion sticks were prepared using the following general
method of preparation. A solution of the thickening polymer and
other structurants in the organic liquid(s) was made by mixing
these materials, heating and agitating the mixture at a temperature
sufficiently high that the polymer and other structurants all
dissolve. The mixture was then allowed to cool to about 95.degree.
C. while stirring with shear. A solution of the antiperspirant
active, preheated to 95.degree. C. was added. After stirring with
shear at about 95.degree. C. for a further 10 minutes, the mixture
was poured into dispensing containers. These were then left to cool
to room temperature.
[0252] If oryzanol and .beta.-sitosterol were used, the orzyanol
was dissolved in the liquids at 60.degree. C. before heating to
about 110.degree. C. and adding the .beta.-sitosterol then cooling
to about 95.degree. C. to add further ingredients.
7 Examples 5.1 5.2 Percent by weight Beta Sitosterol (5) 2.50 1.62
Oryzanol (6) 2.50 2.40 Dextrin Palmitate (4) 1.67 1.35
Cyclomethicone DC 245 (1) 29.98 30.54 C.sub.12-15 Alkyl Benzoate
(7) 12.85 13.09 Abil EM 90 (18) 0.50 -- Lameform TGI (19) -- 1.0
Antiperspirant active solution (16) 50 50
Example and Comparative Example 6
[0253] In this Example and Comparative Example, emulsion sticks
were prepared by the general method described in Example 5
hereinabove using cellobiose octanoate.
8 6.A 6.B Example No Comp 6.1 Comp 6.2 6.3 Kraton G1650 (21) 0.5
0.5 1.0 Cellobiose Octanon- 10 10 7.5 7.5 7.5 anoate (22) DC245 (1)
7.9 7.8 8.4 8.3 8.2 Silkflo 364 (15) 31.6 31.2 33.6 33.2 32.8 Abil
EM90 (18) 0.5 0.5 0.5 0.5 0.5 Water 16 16 16 16 16 Glycerol 9 9 9 9
9 Rezal 36GP SUE (20) 25 25 25 25 25 Properties Hardness (mm) *
13.48 11.94 15.68 14.61 14.04 Pay-off (g) 0.488 0.466 0.571 0.559
0.469
[0254] Examples 6.2 and 6.3 show that the addition of the
thickening polymer increased the hardness of the resultant emulsion
stick, and by visual inspection retained acceptable clarity.
9 Examples 5.3 5.4 5.5 Percent by weight Beta Sitosterol (5) 2.50
3.20 Oryzanol (6) 2.50 4.80 Dextrin Palmitate (4) 1.67 2.67 2.4
Cellobiose octanonanaoate (22) 3.75 Cyclomethicone DC 245 (1) 29.98
27.18 17.3 C.sub.12-15 Alkyl Benzoate (7) 12.85 11.65 -- Silkflo
364NF (15) -- -- 26.4 Abil EM 90 (18) 0.50 0.50 1.0 Antiperspirant
active solution (16) 50 50 -- Antiperspirant active solution (17)
40 Glycerol 10
[0255] Examples 5.1 to 5.4 were opaque sticks which gave a low
visible residue when applied to cloth or carborundum paper in the
procedure described above.
[0256] The stick of Example 5.5 was translucent. The refractive
indices of its continuous and disperse phases were measured as
1.433 at 25.degree. C. The refractive index of cellobiose
octanonanoate was determined as 1.48.
[0257] The transmittance of the composition was measured in
accordance with the method given above and found to be 1.2% at
22.degree. C.
* * * * *