Note: Descriptions are shown in the official language in which they were submitted.
CA 02571906 2006-12-19
G o 1 d s c h m i d t GmbH, Essen
Cold-preparable, low-viscosity and prolonged-stability
cosmetic emulsions
The present invention provides cold-preparable,
prolonged-stability, low-viscosity, fine oil-in-water
emulsions, their preparation from preferably clear oil
phases or via preferably clear to transparent
microemulsion-like concentrates, the corresponding oil
phases or microemulsion-like concentrates and the use
of the inventive emulsions for producing cosmetic,
dermatological or pharmaceutical formulations, and for
the production of cleaning and care emulsions for the
household and industry, especially for the production
of impregnating emulsions for wet wipes or for
sprayable care emulsions.
The inventive fine oil-in-water emulsions are
preferably free of polyethylene glycol-containing
substances ("PEG-free") and comprise an emulsifier
mixture consisting of a primary nonionic emulsifier
component, preferably polyol partial esters, and a
secondary neutralizable emulsifier component, and
additionally interface-active cosurfactants, preferably
aromatic cosurfactants with preservative properties,
and additionally oils, preferably ester and/or ether
oils, and optionally further customary assistants and
additives.
CA 02571906 2006-12-19
- 2 -
Emulsions constitute an important product type in the
field of cosmetic, dermatological and/or pharmaceutical
formulations. Cosmetic formulations are utilized
essentially for skincare. Skincare in the cosmetic
sense is primarily the enhancement and/or
reestablishment of the natural function of the skin as
a barrier against environmental influences (for example
soil, chemicals, microorganisms) and against the loss
of endogenous substances (for example water, natural
fats, electrolytes).
A further aim of skincare is to compensate for the loss
of fats and water in the skin caused by daily washing
and to preserve and restore the softness and smoothness
of the skin. This is important precisely when the
natural regeneration capacity is insufficient.
Moreover, skincare products should provide protection
from environmental influences, especially from the sun
and the wind, and delay skin ageing.
Pharmaceutical topical compositions generally comprise
one or more medicaments in effective concentration. For
the sake of simplicity, cosmetic and medical use and
corresponding products are clearly distinguished by
reference to the legal stipulations of the Federal
Republic of Germany (for example Cosmetics Act, Food
and Drug Laws).
In the last few years, cosmetic wet wipes have gained
CA 02571906 2006-12-19
- 3 -
increasing significance owing to their extremely simple
and convenient usability. Initially, virtually
exclusively wet wipes for cleaning purposes were
represented on the cosmetics market, which comprised
mainly aqueous, surfactant-containing impregnating
solutions. However, in recent times, care products have
also been appearing more and more on the market, which
are based on impregnating emulsions and thus
additionally comprise a care oil component.
Most of these cosmetic wet wipes for bodycare and
facecare are impregnated with emulsions which have been
prepared by the PIT emulsifying method (K. Shinoda, H.
Kunieda, Phase properties of emulsions: PIT and HLB,
Encyci. of Emulsion Technology, 337-367 (1), 1983 or
Th. Forster, F. Schambil, W. von Rybinski, J. Disp.
Sci. And Technology, 13(2), 183-93 (1992)).
The PIT method makes use of the fact that, in an oil-
in-water (O/W) emulsion which is stabilized by nonionic
emulsifiers containing polyethylene glycol ("PEG-
containing emulsifiers"), a phase inversion can be
induced to give a water-in-oil (W/0) emulsion by
increasing the temperature (phase inversion; PIT: phase
inversion temperature).
Since the water-oil interface tension is extremely low
in this phase inversion region, extremely fine oil-in-
water emulsions can thus be obtained after cooling. For
CA 02571906 2006-12-19
- 4 -
this purpose, it is, however, necessary that the
individual components of the emulsions are adjusted
precisely with respect to one another for each system
to be emulsified. This means that emulsifier mixtures
and emulsifier concentration have to be "tailored" for
different oil phases.
The fine and low-viscosity emulsions thus produced have
excellent long-term stability and are thus very
suitable as impregnating solutions for wet wipes. Such
systems are described, for example, in EP-B-1 268 740
or WO-A-00/04230.
A fundamental requirement for the use of PIT
emulsification technology is, as described, the
necessity for the entire emulsion to be heated to
temperatures above the phase inversion temperature and
then to be cooled down again.
At the present time, where process operations have to
be optimized and energy costs restricted, this means a
distinct disadvantage compared to systems which do not
have to pass through this heating/cooling curve. For
this reason, fine, prolonged-stability emulsions which
can be prepared at room temperature ("cold
preparation") without having to pass through an
additional heating/cooling curve would be advantageous.
Another disadvantage in impregnating solutions for wet
CA 02571906 2006-12-19
- 5 -
wipes based on PIT emulsions is that they are based on
the use of PEG-containing emulsifiers. In view of very
natural cosmetic formulations, it is an important aim
of cosmetics research to be able to dispense with
emulsifiers containing polyethylene glycol ("PEG").
There is therefore an increased search for PEG-free
alternative solutions.
It is also known that ethoxylated emulsifiers impart a
rather watery skin feel, which can be improved
sensorily by the use of, for example, polyglyceryl
esters.
For instance, WO-A-02/056841 describes PEG-free
impregnating emulsions for cosmetic wet wipes based on
polyol poly-12-hydroxystearates and alkyl glycosides.
The use of these emulsifier mixtures leads to improved
softness of the paper products impregnated with them
and also leads otherwise to improved sensory properties
in use of the wet wipes produced with them. In the case
of such emulsifier combinations, it is, however,
generally difficult to achieve good long-term stability
of the impregnating emulsions in combination with
sufficient preservation.
Especially in the production of wet wipes, sufficient
preservation of the impregnating solutions is
absolutely necessary in order to prevent germ growth.
The preservation has to be sufficient to protect both
CA 02571906 2006-12-19
- 6 -
the impregnating solutions themselves and finally also
the impregnated wet wipes in the long term against germ
growth.
Preferred preservative mixtures used are typically
mixtures of alkylparaben esters and phenoxyethanol, as
are commercially available, for instance, under the
trade names Euxyl K 300 (Schulke & Mayr) or Phenonip
(Clariant).
The described high requirements regarding reliable
preservation of impregnating solution and wet wipes
make it necessary that relatively large amounts of
these alkylparaben ester/phenoxyethanol mixtures
generally have to be used in the finished impregnating
solutions (0.5 to 1.0% by weight). Ideally, the entire
amount of preservative should be incorporated as early
as in the production of emulsion concentrates. This
allows the desired use concentration of the
impregnating solution to be established subsequently in
a simple manner by dilution with water.
It is known that the use of these alkylparaben
ester/phenoxyethanol mixtures has an emulsion-stressing
influence, since these compounds are very interface-
active and compete with emulsifier molecules for a
space at the oil-water interface. Owing to the
interface-active character of these preservative
mixtures, they can therefore also be described as
CA 02571906 2006-12-19
- 7 -
aromatic cosurfactants with preservative properties. In
the case of impregnating emulsions for wet wipes, this
emulsion-stressing effect is generally enhanced by the
required high amounts of these preservatives and the
low viscosities of the impregnating solutions.
In summary, it can therefore be stated that it is not
possible with the emulsifiers or emulsifier
combinations described in the prior art to prepare
cold-preparable, sufficiently preserved, low-viscosity,
fine and prolonged-stability emulsions, as are
typically used for impregnating emulsions or sprayable
lotions.
It is therefore an object of the present invention to
prepare low-viscosity, fine and prolonged-stability
emulsions, as used typically for impregnating emulsions
or sprayable lotions, i.e. which simultaneously
- can be prepared at room temperature and
- are free of ethoxylated constituents and
- which additionally contain a sufficient amount of
preservative compounds.
It has now been found that, surprisingly, low-
viscosity, fine and prolonged-stability oil-in-water
emulsions, which are outstandingly suitable for use as
impregnating emulsions or in sprayable systems, are
preparable at room temperature when a suitable
CA 02571906 2006-12-19
- 8 -
combination of emulsifiers based on polyol partial
esters and neutralizable acid partial esters is used
together with oils, preferably ester and/or ether oils
and cosurfactants, preferably aromatic cosurfactants
with preservative properties.
In addition to their ease of preparation and their fine
dispersion, these emulsions are notable in that they
are essentially free of ethoxylated ingredients ("PEG-
free" emulsion systems) . The wet wipes produced with
the aid of these impregnating solutions are
additionally notable for exceedingly pleasant sensory
properties.
The inventive oil-in-water emulsions provide for the
first time PEG-free, low-viscosity and fine emulsions
which are preparable at room temperature and are
simultaneously sufficiently preserved and have
prolonged stability by virtue of the use, preferred in
accordance with the invention, of preservation-active
aromatic cosurfactants, and are thus suitable in
particular for use as impregnating emulsions for wet
wipes.
The invention therefore provides prolonged-stability,
low-viscosity, fine oil-in-water emulsions comprising:
A) an emulsifier mixture consisting of:
a) at least one nonionic primary emulsifier and
CA 02571906 2006-12-19
- 9 -
b) at least one secondary emulsifier containing
one or more acid functions, all or some of
which may optionally be neutralized, and
B) one or more cosurfactants and
C) one or more oils and optionally
D) one or more polar solubilizers and optionally
E) customary assistants and additives,
with the proviso that the water phase content of the
emulsions is > 80% by weight based on overall emulsion.
Emulsions preferred in accordance with the invention
have low viscosity, are finely distributed and have
long-term stability.
"Low viscosity" is understood to mean a viscosity which
enables spraying of the emulsions with customary
apparatus. In general, these are emulsion viscosities
of < 4000 mPas (Brookfield RVT, spindle 4, 10 rpm
(20 C)), preferably < 2500 mPas, more preferably
<_ 1000 mPas. Higher viscosities are attainable but not
preferred in accordance with the invention.
"Fine" is understood to mean a mean radius of the
emulsion droplets of > 20 -< 500 nm, preferably of
>_ 30 - <_ 200 nm and more preferably of _ 40 - <_ 120 nm.
"Prolonged stability" is understood to mean that the
inventive emulsions can be stored for three months at
CA 02571906 2006-12-19
- 10 -
room temperature and for 1 month at 40 C without
irreversible creaming or other signs of instability.
The inventive oil-in-water emulsions typically have a
water phase content of _ 70 - _ 99% by weight,
preferably of _ 80 - <_ 97% by weight.
The water phase includes all substances in a
formulation which are added to this phase or can be
dissolved or dispersed in it owing to their hydrophilic
character. Based on the inventive oil-in-water
emulsions, water or any constituents such as glycols,
polyalkylene glycols, glycerol, polyglycerols,
alcohols, water-soluble polymers or active ingredients
in any case belong to the water phase.
In all subjects of the invention, the emulsifier
mixture (A), the cosurfactants (B) and the oils (C) are
used preferably in proportions by weight (based on
these three components) of (A) > 10 -< 30/(B) > 3 -
5 20/(C) > 50 - 5 87 and more preferably in proportions
by weight of 20 - _ 25/> 5-<_ 15/_ 60 - 75, the
emulsifier mixture (A) being composed of > 75 -<_ 99.5%
by weight of nonionic primary emulsifier (a) and _ 0.5
- <_ 25% by weight of secondary emulsifier (b)
containing acid groups.
For the emulsifier mixture (A), preference is given in
accordance with the invention to using, for the
CA 02571906 2006-12-19
- 11 -
nonionic primary emulsifiers (a), polyol partial esters
selected from at least one of the groups of:
al) glyceryl and polyglyceryl partial esters,
preferably prepared by esterifying aliphatic, linear or
branched, optionally unsaturated and/or hydroxy-
functionalized carboxylic acids having a chain length
of from ? 6 to <_ 22 carbon atoms with glycerol,
polyglycerols or mixtures of the two,
a2) sorbitan or sorbitol partial esters, preferably
prepared by esterifying aliphatic, linear or branched,
optionally unsaturated and/or hydroxy-functionalized
carboxylic acids having a chain length of from _ 6 to
5 22 carbon atoms with sorbitol,
a3) carbohydrate esters, preferably glycoside or
sucrose esters, preferably prepared by esterifying
aliphatic, linear or branched, optionally unsaturated
and/or hydroxy-functionalized carboxylic acids having a
chain length of from _ 6 to _ 22 carbon atoms with
mono- or polysaccharides, and optionally higher
saccharides,
a4) (alkylpoly)glycosides, preferably prepared by
reacting aliphatic, linear or branched, optionally
unsaturated and/or additionally hydroxy-functionalized
alcohols having a chain length of from _ 6 to < 22
carbon atoms with mono- or polysaccharides
CA 02571906 2006-12-19
- 12 -
or mixtures thereof.
Typically, the main part of the nonionic primary
emulsifier component (a) consists of polyglyceryl
esters, to which sorbitan esters have preferably been
added in an amount of ? 0-<_ 75% by weight, preferably
? 0 - < 50% by weight, more preferably ? 0 - < 25% by
weight, based on overall primary emulsifier component
(a).
Preference is given to polyglyceryl partial esters and
sorbitan partial esters which contain, as hydrophobic
moieties, fatty acid radicals having a chain length of
from ? 10 to <_ 18 carbon atoms.
Very particular preference is given to a combination of
polyglyceryl laurates and sorbitan laurates.
For the emulsifier mixture (A), preference is given,
for the secondary emulsifier component (b), to
compounds selected from at least one of the groups of:
bl) optionally hydroxyl-containing di- or
polycarboxylates, sulfated, sulfonated or phosphated
carboxylates, malonates, malates, succinates,
sulfosuccinates, citrates, tartrates, in each of which
some of the acid groups have been esterified with
aliphatic or aromatic, linear or branched, optionally
CA 02571906 2006-12-19
- 13 -
unsaturated and/or hydroxy-functionalized alcohols
having a chain length of from _ 6 to S 22 carbon atoms,
b2) optionally hydroxyl-containing di- or
polycarboxylates, sulfated or sulfonated or phosphated
carboxylates, malonates, malates, succinates,
sulfosuccinates, citrates, tartrates, in each of which
some of the acid groups have been esterified with
polyols, polyol partial esters, preferably formed from
glycerol, polyglycerol and/or sorbitol with aliphatic
or aromatic, linear or branched, optionally unsaturated
and/or hydroxy-functionalized carboxylic acids having a
chain length of from _ 6 to < 22 carbon atoms,
b3) polyols, preferably glycerol, polyglycerol and
sorbitol, which have been partly esterified with
aliphatic or aromatic, linear or branched, optionally
unsaturated and/or hydroxy-functionalized mono-, di- or
polycarboxylic acids having a chain length of from _ 2
to 5 22 carbon atoms, with the proviso that free,
neutralizable acid groups are present in the molecule,
b4) hydroxy-functional mono-, di- or polycarboxylic
acids, at least some of whose hydroxyl groups have been
reacted with aliphatic, linear or branched, optionally
unsaturated and/or hydroxy-functionalized carboxylic
acids having a chain length of from ? 6 to <_ 22 carbon
atoms,
CA 02571906 2006-12-19
- 14 -
b5) N-acyl amino acids such as sarcosinates,
glutamates, aspartates, containing an aliphatic or
aromatic, linear or branched, optionally unsaturated
and/or hydroxy-functionalized radical having a chain
length of from > 6 to < 22 carbon atoms,
b6) carboxylates, sulfates, sulfonates, phosphonates
or phosphates, containing an aliphatic or aromatic,
linear or branched, optionally unsaturated and/or
hydroxy-functionalized acyl radical having a chain
length of from _ 6 to _ 22 carbon atoms,
or mixtures thereof.
The emulsifiers of type (b) are present in the
emulsifier formulation preferably in at least partly
neutralized form. They are advantageously used already
as (partly) neutralized components. If desired, the
neutralization step can also be effected in a suitable
later process step, in which case the bases used for
the neutralization are preferably those which lead to
anion-active emulsifiers with mono- or divalent
cationic counterions. Particularly preferred
counterions are sodium and potassium.
Preference is given to using neutralized citric acid
partial esters whose hydrophobic radicals each contain
from _ 10 to <_ 18 carbon atoms.
CA 02571906 2006-12-19
- 15 -
Very particular preference is given to the partial
esters of citric acid and lauryl alcohol or of citric
acid and glyceryl mono- or dilaurates, and also to
partial esters of citric acid and oleyl alcohol or
citric acid and glyceryl mono- or dioleates.
In the context of the present invention, cosurfactants
are understood in particular to mean those compounds
which feature interface activity, which can be
manifested in the lowering of interface tensions or the
incorporation into interface films, but without these
substances taken alone exhibiting the aggregation
typical of surfactants to give micellar structures in
water or the stabilization typical of emulsifiers for
emulsion droplets.
In the context of the present invention, cosurfactants
are additionally or alternatively understood to mean in
particular those compounds which have a HLB value
according to Griffin (calculable according to: J.
T. Davies and E. K. Rideal, Interfacial Phenomena,
Academic Press, New York, 1963) of between _ 4 and
< 10. These cosurfactants more preferably feature an
octanol-water partition coefficient log P or log Ko,
which is between 1 and 2. The octanol-water partition
coefficient is calculated from the decadic logarithm of
the quotient of the amount of a substance dissolved in
octanol and in water in equilibrium at room temperature
(see: 0. Franzle, M. Straskraba in Ullmann's
CA 02571906 2006-12-19
- 16 -
Encyclopedia of Industrial Chemistry, 6 th edition,
Wiley-VCH, Weinheim, 2000).
Advantageously, the inventive cosurfactants are
nonionic organic compounds which have from 4 to 14
carbon atoms and one or more polar groups in the
molecule.
Typical known nonaromatic cosurfactants are aliphatic
alcohols such as butanol, pentanol, hexanol, octanol,
hexanediol or octanediol. In a preferred embodiment of
the invention, the cosurfactants used are n-pentanol,
n-hexanol, 1,2-hexanediol, 1,2-heptanediol or 1,2-
octanediol.
In addition, the cosurfactants used are preferably also
monoalkyl ethers or monoalkyl esters based on glycerol,
ethylene glycol, propylene glycol or diethylene glycol
with fatty acids or alcohols having from 6 to 10 carbon
atoms.
In a preferred embodiment of the invention, the
cosurfactants used are aromatic cosurfactants. In the
context of the present invention, aromatic
cosurfactants are understood in particular to mean
interface-active substances which contain one or more
aryl groups and which, taken alone, do not form any
micellar structures in water.
CA 02571906 2006-12-19
- 17 -
Advantageously, these aromatic cosurfactants
additionally feature antimicrobial properties, i.e.
they are aromatic cosurfactants with preservative
properties. The use of such cosurfactants enables the
preparation of inventive O/W emulsions which ideally
need no further preservatives. In addition, it is of
course possible to add further customary preservatives
(as assistants and additives), as described, for
instance, in DE102005011785.6.
Aromatic cosurfactants which have preservative
properties and are particularly preferred in accordance
with the invention are phenoxyethanol and benzyl
alcohol, alone or in combination with one or more
alkylparaben esters, preferably methylparaben,
ethylparaben, propylparaben, isopropylparaben,
butylparaben and/or isobutylparaben. Particular
preference is given to the use of mixtures of
alkylparaben esters and phenoxyethanol, as are
commercially available under the trade names Euxyl(D K
300 (Schulke & Mayr) or Phenonip (Clariant).
As mentioned, it is also possible to use mixtures of
said preservation-active aromatic cosurfactants with
other suitable preservatives. For example, it is also
possible to use a mixture of phenoxyethanol and
ethylhexyl glycerol, as is commercially available under
the name Euxyl PE 9010 (Schulke & Mayr).
CA 02571906 2006-12-19
- 18 -
In the context of the present invention, oils are
understood to mean in particular compounds selected
from the group of Guerbet alcohols based on fatty
alcohols having from 6 to 20, preferably from 8 to 10
carbon atoms, esters of linear C1-C44-fatty acids with
linear Cl-C22-fatty alcohols, esters of branched
C1-C44-carboxylic acids with linear C1-C22-fatty
alcohols, esters of linear C1-C44-fatty acids with
branched alcohols, esters of linear and/or branched
fatty acids with polyhydric alcohols and/or Guerbet
alcohols, triglycerides based on C1-C44-fatty acids,
vegetable oils, branched primary alcohols, substituted
cyclohexanes, Guerbet carbonates, dialkyl(ene) ethers,
dialkyl(ene) carbonates and/or aliphatic or naphthenic
hydrocarbons, silicone oils, dimethicones,
cyclomethicones, ethoxylated and/or propoxylated
organic alcohols, ethoxylated and/or propoxylated
organic acids or mixtures thereof. Perfume oils known
to those skilled in the art may also serve as the oil
phases in the context of the invention.
In a preferred embodiment of the invention, the oils
used are ester oils, ether-based oils, hydrocarbons and
propoxylated organic alcohols, and mixtures of these
compounds.
Useful ester oils include in particular mono- or
diesters of linear and/or branched mono- and/or
dicarboxylic acids having from _ 2 to <_ 44 carbon atoms
CA 02571906 2006-12-19
- 19 -
with linear and/or branched (especially 2-
ethylhexanol), saturated or unsaturated alcohols having
from > 1 to <_ 22 carbon atoms. Likewise suitable in the
inventive context are the esterification products of
aliphatic, difunctional or trifunctional alcohols
(especially dimer diol and/or trimer diol) having from
>_ 2 to < 36 carbon atoms with one or more
monofunctional aliphatic carboxylic acids having from
>- 1 to <_ 22 carbon atoms. Also suitable in accordance
with the invention are ester oils which= contain
aromatic groups.
The partial use of ester oils which have waxy character
at room temperature, for instance myristyl myristate,
can lead to a richer skin feel of the emulsions.
Useful ether oils are in particular dialkyl ethers
having from _ 4 to <_ 24 carbon atoms. Particularly
suitable in accordance with the invention are saturated
C6-C18-dialkyl ethers, for example di-n-octyl ether,
di(2-ethylhexyl) ether, lauryl methyl ether or octyl
butyl ether, and also didodecyl ether.
Particularly preferred oil components are the cosmetic
ester oils ethylhexyl palmitate, ethylhexyl stearate,
decyl cocoate, diethylhexyl carbonate, dioctyl
carbonate, cetearyl ethylhexanoate, decyl oleate,
isocetyl palmitate, cetearyl isononanoate, hexyl
laurate, isopropyl isononanoate, isopropyl palmitate,
CA 02571906 2006-12-19
- 20 -
isopropyl myristate, isopropyl laurate and C12-15 alkyl
benzoate, and the cosmetic ether oil dicaprylyl ether,
and the propoxylated organic alcohols PPG15 stearyl
ether or PPG-4 butyl ether, and mixtures of the
compounds mentioned.
In the context of the present invention, A%polar
solubilizers" are understood to mean in particular
polar compounds which are added in amounts of up to 10%
by weight to the oil phases described below in order to
obtain clear oil phases. They are preferably water,
glycols, polyalkylene glycols, glycerol, polyglycerol
or short-chain alcohols such as ethanol or isopropanol.
The assistants and additives used may be all assistants
and additives known as prior art to the person skilled
in the art in this field, such as oils and waxes,
commercial surfactants or emulsifiers, bodying agents,
thickeners, for example based on polymer, inorganic and
organic UV light protection filters, self-tanning
agents, pigments, antioxidants, hydrotropes, active
deodorant and antiperspirant ingredients, other active
ingredients, dyes, additional preservatives and
perfumes, as described, for instance, in
DE102005011785.6.
The assistants and additives may be added either to the
oil or to the water phase, or to the diluent water in
the preparation process of the emulsion.
CA 02571906 2006-12-19
- 21 -
Prefered active ingredients are in particular
tocopherol, tocopherol acetate, tocopherol palmitate,
ascorbic acid, deoxyribonucleic acid, coenzyme Q10,
retinol and retinyl derivatives, bisabolol, allantoin,
phytantriol, panthenol, AHA acids, amino acids,
hyaluronic acid, creatine (and creatine derivatives),
guanidine (and guanidine derivatives), ceramides,
phytosphingosine (and phytosphingosine derivatives),
sphingosine (and sphingosine derivatives),
pseudoceramides, essential oils, peptides, protein
hydrolyzates, plant extracts and vitamin complexes.
The inventive O/W emulsions can in principle be
prepared utilizing a simple stirrer apparatus. No
1.5 additional homogenization step is required.
The preparation is preferably effected at room
temperature by directly pouring a clear, monophasic oil
phase comprising an emulsifier mixture, cosurfactants,
oils and optionally customary assistants and additives
into diluent water. If necessary, the oil phase may be
converted to a clear phase by adding up to 10% by
weight of a polar solubilizer. Such polar solubilizers
may be water, glycols, polyalkylene glycols, glycerol,
polyglycerols or short-chain alcohols such as ethanol
or isopropanol. The polar solubilizer used is
preferably water.
Homogeneous, clear oil phases are advantageous for the
CA 02571906 2006-12-19
- 22 -
preparation of inventive fine O/W emulsions. The use of
cloudy oil phases leads generally to relatively coarse
emulsions whose long-term stability is often
insufficient. The transition from clear to cloudy oil
phases is fluid. The opacity at which emulsions with
sufficient long-term stability can be prepared is
dependent upon the type and amount of the components
used and should be determined individually in these
limiting cases.
Alternatively to the method mentioned, inventive fine
oil-in-water emulsions can also be effected via the
intermediate stage of a clear to transparent
microemulsion-like concentrate. This concentrate
consists generally of > 30 -< 90% by weight of oil
phase, preferably of _ 40 - S 80% by weight of oil
phase, comprising an emulsifier mixture, cosurfactants,
oils and optionally polar solubilizers and/or customary
assistants and additives. These clear to transparent
microemulsion-like concentrates are preferably prepared
at room temperature by stirring water into the oil
phase. To prepare these concentrates, it is also
possible to use cloudy oil phases. The optimal water
content of the concentrates is formulation-dependent
(for example on the oil used), but is generally _ 10
- < 70% by weight, preferably _ 20 - 5 60% by weight.
These microemulsion-like concentrates may finally be
diluted to give inventive oil-in-water emulsions. Both
CA 02571906 2006-12-19
- 23 -
the preparation of the microemulsion-like concentrates
and the final dilution step can be effected at room
temperature using a simple stirrer apparatus.
The invention therefore further provides oil phases
comprising:
A) an emulsifier mixture consisting of:
a) at least one nonionic primary emulsifier and
b) at least one secondary emulsifier containing
one or more acid functions, all or some of
which may optionally be neutralized, and
B) one or more cosurfactants and
C) one or more oils and
D) from > 0 to < 10% by weight (based on the
overall oil phase) of one or more polar
solubilizers and optionally
E) customary assistants and additives.
Preference is given in accordance with the invention to
homogeneous and clear oil phases.
These oil phases can be prepared by the known prior art
processes_ For example, the oil phases, depending on
the consistency and concentration of the components
used, can be prepared by simply mixing the components
at temperatures in the range of _> 20 to < 75 C. These
oil phases can be used at room temperature to prepare
the inventive oil-in-water emulsions.
CA 02571906 2006-12-19
- 24 -
The invention further provides a process for preparing
inventive oil-in-water emulsions, wherein these clear
oil phases are preferably adjusted to a total water
phase content of _ 70% by weight, preferably ? 80% by
weight, at temperatures of less than 40 C, especially
room temperature, with an appropriate water phase under
conditions known per se.
The invention further provides clear to transparent
microemulsion-like concentrates comprising:
A) an emulsifier mixture consisting of:
a) at least one nonionic primary emulsifier and
b) at least one secondary emulsifier containing
one or more acid functions, all or some of
which may optionally be neutralized, and
B) one or more cosurfactants and
C) one or more oils and optionally
D) one or more polar solubilizers and optionally
E) customary assistants and additives,
with the proviso that the total water phase content of
the microemulsion-like concentrates is from _ 10 to
< 70% by weight, based on the overall concentrate.
The invention further provides a process for preparing
inventive oil-in-water emulsions, wherein these
microemulsion-like concentrates are preferably adjusted
CA 02571906 2006-12-19
- 25 -
to a total water phase content of _ 70% by weight,
preferably _ 80% by weight, at temperatures of less
than 40 C, especially room temperature, with an
appropriate water phase under conditions known per se.
The invention further provides for the use of the
inventive emulsions for producing cosmetic,
dermatological or pharmaceutical formulations. In
particular, the use as impregnating solutions for
producing wet wipes, very particularly cosmetic wet
wipes for the care and cleaning of the skin, are at the
forefront.
The invention further provides for the use of the
emulsions in cosmetic cleaning and care formulations
for skin and skin appendages. In particular, the use in
sprayable formulations is at the forefront, as used,
for instance, for facecare and bodycare products,
babycare, sun protection preparations, makeup removers
and antiperspirants/deodorants.
The inventive oil-in-water emulsions are also
outstandingly suitable both for the production of
cleaning and care wet wipes and for direct use in the
form of sprayable emulsion systems for the cleaning and
care of surfaces in the household and industry, for
example textile care, leather care, the care and
cleaning of metallic or nonmetallic surfaces, for
example for the cleaning and care of automobiles or
CA 02571906 2006-12-19
- 26 -
furniture.
The invention accordingly further provides for the use
of the emulsions for producing cleaning compositions
and care compositions for the household and industry,
such as textiles, leather, plastics, metallic and
nonmetallic surfaces. In particular, the use as
impregnating solutions for producing wet wipes and the
use in sprayable formulations are at the forefront.
The technical teaching described here enables, in a
simple manner, the preparation at room temperature of
PEG-free, low-viscosity, fine and prolonged-stability
oil-in-water emulsions which already have sufficient
preservation.
CA 02571906 2006-12-19
- 27 -
Working examples:
The examples which follow are intended to illustrate
the subject matter of the invention in detail without
restricting it to these examples.
The concentrations in all examples are reported as % by
weight.
The inventive oil phases, the inventive microemulsion-
like concentrates and the inventive emulsions were
prepared using a simple manual stirrer apparatus. After
the corresponding oil phases had been prepared, both
the conversion to inventive microemulsion-like
concentrates and to inventive oil-in-water emulsions
were effected at temperatures of < 30 C.
In the case of preparation of the emulsions, it is
advantageous to use the acid partial esters (b) used as
part of the emulsifier mixture at least in partly
neutralized form from the start. However, it is also
possible to perform this neutralization step at a later
point in the preparation process and initially to work
with the non-neutralized acid partial esters.
In the examples, the acid partial esters used were used
in neutralized form.
CA 02571906 2006-12-19
- 28 -
Example emulsifiers 1-11:
Description of the emulsifier systems used in the
example formulations (the total percentages (by weight)
per emulsifier system in each case add up to 100):
Emulsifier 1:
Emulsifier component A: 97% polyglyceryl-4 lauratel)
Emulsifier component B: 3% dilauryl citrateZ)
Emulsifier 2:
Emulsifier component A: 96% polyglyceryl-4 lauratel}
Emulsifier component B: 4% dilauryl citrate2)
Emulsifier 3:
Emulsifier component A: 95% polyglyceryl-4 lauratel)
Emulsifier component B: 5% dilauryl citrate2)
Emulsifier 4:
Emulsifier component A: 92% polyglyceryl-4 lauratel)
Emulsifier component B: 8% dilauryl citrate2)
Emulsifier 5:
Emulsifier component A: 98.5% polyglyceryl-4 lauratel)
Emulsifier component B: 1.5% disodium lauryl sulfo-
succinate3
CA 02571906 2006-12-19
- 29 -
Emulsifier 6:
Emulsifier component A: 98.5% polyglyceryl-3 laurate4'
Emulsifier component B: 1.5% potassium cetyl phosphate5)
Emulsifier 7:
Emulsifier component A: 77% polyglyceryl-4 lauratel)
19% sorbitan laurate6)
Emulsifier component B: 4% dilauryl citrate2)
Emulsifier 8:
Emulsifier component A: 64% polyglyceryl-6 laurate7)
29% polyglyceryl-4 lauratel)
Emulsifier component B: 7% dilauryl citrate2)
Emulsifier 9:
Emulsifier component A: 49% polyglyceryl-6 laurate')
46% sorbitan laurate6)
Emulsifier component B: 5% dilauryl citrate2)
Emulsifier 10:
Emulsifier component A: 19% polyglyceryl-10 laurate8)
77% sorbitan laurate6)
Emulsifier component B: 4% dilauryl citrate2)
Emulsifier 11:
Emulsifier component A: 94% polyglyceryl-4 laurate')
Emulsifier component B: 6% dilauryl citrate2)
1) TEGOc" Care PL 4 (Degussa)
CA 02571906 2006-12-19
- 30 -
2) Partly KOH-neutralized diester formed from lauryl
alcohol and citric acid
3) REWOPOL SB F 12 P (Degussa)
4) Polyglyceryl-3 laurate having a degree of
esterification of 20% of the OH groups
5) Amphisol K (Roche)
6) TEGO SML ( Degussa )
7) Polyglyceryl-6 laurate having a degree of
esterification of 13% of the OH groups
8) Polyglyceryl-10 laurate having a degree of
esterification of 8% of the OH groups
CA 02571906 2006-12-19
- 31 -
Examples of clear oil phases 1-10:
These examples are intended to show in particular the
composition of inventive clear oil phases (data in % by
weight) which can be processed in a further step at
room temperature to give inventive, fine oil-in-water
emulsions (see example emulsions 1-10).
Clear oil phases 1 2 3 4 5
Emulsifier 2 22.0% 20.8%
Emulsifier 3 22.0% 22.0%
Emulsifier 5 22.0%
isopropyl palmitate 66.0% 66.0% 66.0%
ethylhexyl palmitate 62.5%
diethylhexyl carbonate 66.0%
Euxyl K 300g) 12 . 0% 12 . 0% 11.7% 12 . 0%
benzyl alcohol 12.0%
water 5.0%
9) Euxyl K 300 (Schtilke & Mayr): phenoxyethanol,
methylparaben, ethylparaben, propylparaben,
butylparaben, isopropylparaben
CA 02571906 2006-12-19
- 32 -
Clear oil phases 6 7 8 9 10
Emulsifier 5
Emulsifier 7 23.6% 22.9%
Emulsifier 8 21.7%
Emulsifier 11 23.4% 23.5%
sorbitan octanoate10j 1.7% 2.8%
isopropyl palmitate 35.1% 35.0%
ethylhexyl palmitate 70.70 68.7%
C12-15 alkyl benzoate 65.1%
isohexadecane 35.10
Paraffin oil 35.0%
(25 mPas at 30 C)
phenoxyethanol 3.70
Euxyl K 300" 12 . 2 0 7. 4 0 4. 7 0
Euxyl PE 90101" 5.7%
water 1.0% 1.0o
lo)TEGOTENS SD (Degussa)
11)Euxyl PE 9010 (Schiilke & Mayr): phenoxyethanol,
ethylhexylglycerol
CA 02571906 2006-12-19
- 33 -
Examples of clear to transparent microemulsion-like
concentrates 1-10:
These examples are intended to show in particular the
composition of inventive clear to transparent
microemulsion-like concentrates (data in % by weight)
which can be processed in a further step at room
temperature to give inventive, fine oil-in-water
emulsions (see example emulsions 11-20).
Microemulsion- 1 2 3 4 5
like concentrates
Emulsifier 1 14.30 13.2%
Emulsifier 4 9.1%
Emulsifier 6 8.8%
Emulsifier 7 12.5%
decyl cocoate 39.60
ethylhexyl 42.9% 26.4% 27.4% 37.5%
palmitate
Euxyl K 3009) 7. 8 0 7. 2 0 4. 8 0 8. 5 0
phenoxyethanol 5.00
water 35.00 40.00 60.0% 55.0% 45.0%
CA 02571906 2006-12-19
- 34 -
Microemulsion-like 6 7 8 9 10
concentrates
Emulsifier 2 14.3%
Emulsifier 7 13.2%
Emulsifier 9 14.3%
Emulsifier 10 18.6%
Emulsifier 11 14.3%
diethylhexyl 42.8% 32.2%
carbonate
ethylhexyl 42.9% 55.9%
palmitate
cetearyl 39.6%
isononanoate
cyclopentasiloxane 10.7%
Euxyl K 3009) 7. 8 0 10 . 5 0
phenoxyethanol 7.8%
benzyl alcohol 7.2%
capryl glycol12) 2.9%
water 140.0% 35.0% 15.00 40.00 35.0%
12)Dermosott Octiol (Dr. Straetmans) (1,2-octanediol)
CA 02571906 2006-12-19
- 35 -
Example emulsions 1-24:
Emulsions 1-24 are intended to illustrate the structure
of inventive emulsions by way of example (data in % by
weight).
Emulsions 1-10 were prepared by pouring the clear oil
phases (examples 1-10 (see above)) into water at room
temperature using a simple manual stirrer apparatus.
Emulsions 11-20 were likewise prepared at room
temperature by diluting the clear to transparent
microemulsion-like concentrates (corresponding examples
1-10 (see above)) using a simple manual stirrer
apparatus.
Example emulsions 21-24 are based on the clear oil
phases 2 and 3 and were prepared therefrom by diluting
with mixing. By way of example, water-soluble
assistants and additives were added to the water phase.
In some examples, perfume was added in accordance with
the invention as an assistant and additive, which was
dissolvable immediately in the appropriate amounts in
the clear oil phases or in clear to transparent
microemulsion-like concentrates.
All example emulsions are low in viscosity, have fine
distribution and have long-term stability.
CA 02571906 2006-12-19
- 36 -
Example emulsions 1 2 3 4 5
Emulsifier 2 1.25% 1.25%
1.250
Emulsifier 3 1.25%
Emulsifier 5 1.25%
isopropyl palmitate 3.75% 3.750 3.75%
ethylhexyl palmitate 3.75%
diethylhexyl carbonate 3.75%
Euxyl K 3009) 0. 7 0 0.7% 0.7% 0. 7 0
benzyl alcohol 0.7%
perfume 0.20
water 94.30 94.30 94.3% 94.3% 94.10
Example emulsions 6 7 8 9 10
Emulsifier 7 1.25% 2.5%
Emulsifier 8 1.25%
Emulsifier 11 4.0% 5.0%
sorbitan octanoate10) 0.3% 0.6%
isopropyl palmitate 6.0% 7.5%
ethylhexyl palmitate 3.75% 7.5%
C12-15 alkyl benzoate 3.75%
isohexadecane 6.0%
Paraffin oil 7.5%
(25 mPas at 30 C)
phenoxyethanol 0.80
Euxyl K 300" 0. 7 0 0. 8 0 0. 8 %
Euxyl PE 90101" 0. 39.
perfume 0.2% 0.20 0.2%
water (total) 94.10 94.5% 89.00 82.9% 78.60
CA 02571906 2006-12-19
- 37 -
Example emulsions 11 12 13 14 15
Emulsifier 1 1.25% 1.25%
Emulsifier 4 0.75%
Emulsifier 6 1.25%
Emulsifier 7 1.25%
decyl cocoate 3.75%
ethylhexyl palmitate 3.75% 3.75% 2.25% 3.75%
phenoxyethanol 0.50
Euxyl K 300" 0. 7 0 0. 7 0 0. 7 0 0. 7 0
perfume 0.2% 0.2% 0.2%
water (total) 94.10 94.10 94.1% 96.3% 94.3%
Example emulsions 16 17 18 19 20
Emulsifier 2 1.25%
Emulsifier 7 1.25%
Emulsifier 9 1.25%
Emulsifier 10 1.25%
Emulsifier 11 2.5%
diethylhexyl carbonate 7.5% 2.81%
ethylhexyl palmitate 3.75% 3.75%
cetearyl isononanoate 3.75%
cyclopentasiloxane 0.94%
Euxyl K 3009' 0.7% 0. 7 0
phenoxyethanol 0.70
benzyl alcohol 0.7%
capryl glycol12) 0. 5 0
perfume 0.2% 0.2% 0.2%
water (total) 94.1% 94.10 94.1% 89.5% 94.3%
CA 02571906 2006-12-19
- 38 -
Example emulsions 21 22 23 24
Emulsifier 2 1.25% 1.25% 1.25% 1.25%
ethylhexyl palmitate 3.75% 3.75%
diethylhexyl carbonate 3.75% 3.75%
Euxyl K 3009) 0.7% 0.7% 0.7% 0.7%
ethanol 3.0%
glycerol 3.0o
panthenol 0.5%
creatine 0.25%
water (total) 91.3% 91.3% 93.8% 94.05%
CA 02571906 2006-12-19
- 39 -
Particle size determination by dynamic light
scattering:
By way of example for the extremely fine degree of
dispersion of the inventive emulsions, the particle
size of individual example emulsions was characterized
with the aid of dynamic light scattering.
Dynamic light scattering is based on the analysis of
the variations of the scattered light intensity of
diffusing particles in solution. For dilute solutions,
it is possible thereby to determine the coefficient of
diffusion of the particles in solution, which can be
converted via the Stokes-Einstein equation to a mean
hydrodynamic radius <rh> of the particles (here:
emulsion droplets).
In the present case, the example emulsions mentioned
were diluted by a factor of 10 with demineralized water
and characterized with the aid of a dynamic light
scattering instrument from Malvern Instruments
(HPPS 3.1) at 25 C. In each case, the mean values of
three measurements in each case are reported with 100
seconds of measurement time in each case.
CA 02571906 2006-12-19
- 40 -
Example emulsion <rh> in nm
2 55
3 60
6 75
8 75
18 110
20 45
