Polyglycerol fatty acid ester mixture

Polyglycerol fatty acid ester mixtures of mono- di- and polyesters of polyglycerols having a degree of polymerization of 2 to 8 and at least one saturated and/or unsaturated fatty acid, the mixtures having an HLB of greater than 8 and containing 0 to less than 5 wt-% diglycerol fatty acid esters, 20 to 65 wt-% triglycerol fatty acid esters, 20 to 50 wt-% tetraglycerol fatty acid esters and 5 to 40 wt-% higher polyglycerol fatty acid esters, in which the fatty acid component consists of one or more fatty acids selected from the saturated and/or unsaturated, branched and/or unbranched C.sub.6 - to C.sub.14 -fatty acids containing less than 10 wt-% fatty acids having more than 14 carbon atoms; bath additive preparations containing such polyglycerol fatty acid ester mixtures; methods of using such polyglycerol fatty acid ester mixtures, and a process for preparing such mixtures.

BACKGROUND OF THE INVENTION 
The present invention relates to a polyglycerol fatty acid ester mixture of 
mono-, di- and polyesters of polyglycerols having a degree of 
polymerization of 2 to 8 and at least one saturated and/or unsaturated 
fatty acid; to a bath additive composition containing this polyglycerol 
fatty acid ester mixture; to the use of the polyglycerol fatty acid ester 
mixture, and to a process for preparing the polyglycerol fatty acid ester 
mixture. 
It is already known to employ polyglycerol fatty acid esters and ester 
mixtures as surface-active compounds for the preparation and stabilization 
of oil/water and water/oil systems because of their lipophilic and 
hydrophilic properties. These polyglycerol fatty acid esters are 
non-defined partial esters of polyglycerols with saturated and/or 
unsaturated fatty acids, there being numerous possibilities for the 
preparation of emulsifiers and solubilizers having suitably balanced fat 
and water solubility. The HLB of polyglycerol fatty acid esters or ester 
mixtures depends on their composition. This is determined by the synthesis 
route, in particular by the type and ratio of the reactants and by the 
reaction conditions. 
The preparation of surface-active compounds having very specific HLBs by 
esterification of polyglycerol with fatty acids, however, poses various 
problems. 
On the one hand, the reaction mechanisms with respect to the selectivity of 
the esterification and the number of substitutions occurring on the 
polyglycerol basic skeleton are to date largely unknown, so the activity 
of the polyglycerol fatty acid esters as emulsifiers and solubilizers can 
neither be checked nor clearly predicted. 
It is particularly difficult, therefore, to prepare products having very 
specific surface-active properties by esterification of mixtures of 
various glycerol oligomers with fatty acids, especially as mixtures of 
this type, due to the industrial processes for their preparation, 
frequently consist of a large number of different polyglycerols and a 
relatively greater or lesser amount of cyclic glycerol oligomers. 
On the other hand, the hydrophilic and lipophilic properties of the 
polyglycerol fatty acid esters are determined by the esterified fatty 
acids, the polyglycerol basic skeleton and the degree of esterification. 
In this connection, the increasing hydrophilicity of the polyglycerols 
with increasing degree of polymerization, the specific surface activity of 
the fatty acids and fatty acid mixtures selected in each case as the 
esterification product, their solubility in the polyglycerol and the 
unusually high decrease in the HLB of the polyglycerol fatty acid esters 
or ester mixtures when using fatty acids having high molecular weights are 
particularly to be taken into account. Additionally, the esterification 
ratio is dependent on the Weight or molar ratios of the reactants 
employed, polyglycerol and fatty acid, to one another. 
In the prior art, polyglycerol fatty acid esters having defined properties 
have been prepared until now by esterification under controlled conditions 
of very specific glycerol oligomers, such as, for example, triglycerol or 
tetraglycerol, preferably with the use of protective groups. 
The use of polyglycerol mixtures as the esterification starting material is 
known, for example, from published German Patent Application No. DE 
4,023,593. This document describes esterification of a polyglycerol 
mixture which not only has a wide distribution with respect to the 
glycerol oligomers contained in it, but which also, due to the process by 
which it is prepared, contains a relatively greater or lesser amount of 
cyclic polyglycerols. The esterification product according to published 
German Patent Application No. DE 4,023,593 is a non-liquid surfactant 
whose action as an oil-in-water emulsifier is unsatisfactory, particularly 
with respect to the HLB (hydrophilic-lipophilic balance) achieved and the 
stability of the emulsions prepared. 
Ethereal, mineral and also fatty animal and vegetable oils are very 
difficult to emulsify and/or solubilize, and there is a need for 
emulsifiers and/or solubilizers Which can effectively emulsify and/or 
solubilize these oils. Past attempts to use polyglycerol fatty acid esters 
or ester mixtures to emulsify or solubilize such oils have yielded only 
unsatisfactory results. 
SUMMARY OF THE INVENTION 
It is the object of the present invention to provide a polyglycerol fatty 
acid ester mixture which is a water-soluble liquid and is useful as an 
emulsifier for preparing stable oil-in-water systems. 
Another object of the invention is to provide a polyglycerol fatty acid 
ester mixture in which the polyglycerol component contains a narrow 
distribution of glycerol oligomers and little or no cyclic components. 
A further object of the invention is to provide a polyglycerol fatty acid 
ester mixture which is suitable for emulsifying and/or solubilizing 
ethereal, mineral and/or fatty animal and vegetable oils, which are 
normally difficult to emulsify or solubilize. 
Additionally it is an object of the invention to provide a polyglycerol 
fatty acid ester mixture which has a high hydrophilicity. 
It is also an object of the invention to provide a polyglycerol fatty acid 
ester mixture which has advantageous dermatological and toxicological 
properties so that it can be used provide skin-care effects in cosmetic 
and/or pharmaceutical preparations. 
These and other objects of the invention are achieved by providing a 
polyglycerol fatty acid ester mixture of mono-, di- and polyesters of a 
polyglycerol having a degree of polymerization of 2 to 8 and at least one 
fatty acid selected from the group consisting of saturated and 
unsaturated, branched and unbranched C.sub.6 - to C.sub.14 -fatty acids 
containing less than 10 wt-% of fatty acids having more than 14 carbon 
atoms, wherein said polyglycerol fatty acid ester mixture has an HLB of 
greater than 8 and contains 
0 to 5 parts by weight diglycerol fatty acid esters, 
20 to 65 parts by weight triglycerol fatty acid esters, 
20 to 50 parts by weight tetraglycerol fatty acid esters, and 
5 to 40 parts by weight higher polyglycerol fatty acid esters, 
in a total of 100 parts by weight of said ester mixture. 
In accordance with a further aspect of the invention, the objects are also 
achieved by providing a process for preparing a polyglycerol fatty acid 
ester mixture of mono-, di- and polyesters of polyglycerols having a 
degree of polymerization of 2 to 8 and at least one saturated and/or 
unsaturated fatty acid, said process comprising the steps of initially 
heating a reaction mixture comprising 
a polyglycerol containing 0 to 5 wt-% diglycerol, 20 to 65 wt-% 
triglycerol, 20 to 50 wt-% tetraglycerol, and 5 to 40 wt-% higher 
polyglycerols, and 
at least one fatty acid selected from the group consisting of saturated and 
unsaturated, branched and unbranched C.sub.6 - to C.sub.14 -fatty acids 
containing less than 10 wt-% fatty acids having more than 14 carbon atoms, 
in a molar ratio of polyglycerol to fatty acid of 4:1 to 1:1 and in the 
presence of at least one catalyst, to a temperature of at least 
140.degree. C. and reducing the pressure to at most 600 mbar; 
subsequently heating the reaction mixture in a temperature range from 
140.degree. to 220.degree. C. under control of a temperature program, and 
simultaneously reducing the pressure under control of a pressure program 
from 600 to 10 mbar; 
removing resulting water of reaction by continuous distillation, and 
upon attaining an acid number of less than 3, cooling the resulting 
polyglycerol fatty acid ester mixture. 
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
It has now been found that a polyglycerol fatty acid ester mixture 
containing: 
0 to 5 parts by weight diglycerol fatty acid esters, 
20 to 65 parts by weight triglycerol fatty acid esters, 
20 to 50 parts by weight tetraglycerol fatty acid esters, and 
5 to 40 parts by weight higher polyglycerol fatty acid esters 
for a total of 100 parts by weight, in which the fatty acid component 
consists of one or more fatty acids selected from the saturated and/or 
unsaturated, branched and/or unbranched C.sub.6 - to C.sub.14 -fatty acids 
containing less than 10 wt-% of fatty acids having more than 14 carbon 
atoms, and the HLB of the polyglycerol fatty acid ester mixture is greater 
than 8, has all the advantageous properties required to achieve the 
objects of the invention. 
It has furthermore been found that the liquid polyglycerol fatty acid ester 
mixture according to the invention is not only outstandingly suitable for 
the emulsification and solubilization of oils and oily compounds or 
compositions, in particular ethereal and fatty vegetable or animal oils, 
but surprisingly also causes a spontaneous emulsification of the 
aforementioned oils, in particular even in dilute aqueous solutions. The 
mixing of these oils with the polyglycerol fatty acid ester mixture 
according to the invention results in optically clear liquids, since the 
oily compound is solubilized to a great extent. 
On the basis of its high hydrophilicity, the polyglycerol fatty acid ester 
mixture according to the invention can be used as a solvent and 
emulsifier, solubilizer, wetting agent and dispersing agent for the 
preparation of stable oil/water systems. Products, in particular cosmetic 
and pharmaceutical preparations which contain the polyglycerol fatty acid 
ester mixture according to the invention as a surfactant, are indefinitely 
stable at the customary test temperatures and thus cause no storage and 
transport problems. Small concentrations of acid or salt also cannot 
disturb the established phase equilibrium: for example no turbidity or 
precipitates occur in a mixture of 1 part by weight of the polyglycerol 
fatty acid ester mixture according to the invention and 100 parts by 
weight of a 10% strength by weight sodium chloride solution. The 
polyglycerol fatty acid ester mixture according to the invention is 
therefore combinable with a large number of substances and can find a wide 
range of application. 
Compared with the ethoxylates frequently employed as emulsifiers, 
solubilizing agents and wetting agents, the polyglycerol fatty acid ester 
mixture according to the invention has a better biodegradability and can 
additionally be incorporated into cosmetic and pharmaceutical preparations 
and foodstuffs without problems on account of its advantageous 
toxicological and dermatological properties. 
The polyglycerol fatty acid ester mixture according to the invention 
moreover has a high skin-care action and in particular a high 
oil-restoring capacity. 
According to a preferred embodiment, the polyglycerol fatty acid ester 
mixture according to the invention contains: 
0 to 3 parts by weight diglycerol fatty acid esters, 
22 to 32 parts by weight triglycerol fatty acid esters, 
39 to 49 parts by weight tetraglycerol fatty acid esters, and 
24 to 34 parts by weight higher polyglycerol fatty acid esters, 
for a total of 100 parts by weight, in which the fatty acid component 
consists of one or more fatty acids selected from the saturated and/or 
unsaturated, branched and/or unbranched C.sub.8 - to C.sub.12 -fatty acids 
containing less than 5 wt-% of fatty acids having more than 14 carbon 
atoms, and in which the HLB of the polyglycerol fatty acid ester mixture 
is greater than 10. 
According to a preferred embodiment, the polyglycerol fatty acid ester 
mixture according to the invention contains 5 to 20 percent by weight of 
pentaglycerol fatty acid esters. 
As used herein the term "higher polyglycerol fatty acid esters" refers to 
derivatives of glycerol oligomers which have 5 to 8 glycerol units in the 
molecule, i.e. which have a degree of polymerization of 5 to 8. 
Suitable fatty acids in the polyglycerol fatty acid ester mixture according 
to the invention include all saturated and unsaturated, branched and 
unbranched C.sub.6 - to C.sub.14 -fatty acids, individually or in mixtures 
with one another. It has been found that the lower limit in the carbon 
atom number is fixed by that fatty acid which, with the shortest chain, 
just still shows surface activity as the esterification product. Since 
fatty acids having C.sub.15 and higher carbon chains dissolve poorly in 
polyglycerol, the upper limit of the fatty acids selected according to the 
invention is fixed by those having a maximum carbon atom number of about 
14. 
However, it has been shown that low contents of fatty acids having C.sub.15 
and higher carbon chains do not interfere with the particular 
surface-active properties of the polyglycerol fatty acid ester mixture 
according to the invention, which is why the fatty acids selected 
according to the invention can have a content of less than 10 per cent by 
weight, preferably less than 5 per cent by weight, of fatty acids having 
more than 14 carbon atoms, it also being possible by this means to 
incorporate certain additional properties in the polyglycerol fatty acid 
ester mixture according to the invention. 
Preferably, the fatty acid component consists of caprylic acid, capric 
acid, lauric acid, undecenoic acid, 2-ethylhexanoic acid and/or coconut 
fatty acid. In particular, these fatty acids are used to incorporate 
certain additional properties, such as skin-care or antimycotic actions, 
in the polyglycerol fatty acid ester mixture according to the invention. 
Particularly advantageous properties with respect to caring action and 
surface activity are furthermore achieved if the polyglycerol fatty acid 
ester mixture according to the invention consists to more than 50 per cent 
by weight of mono- and diesters. 
The present invention furthermore relates to a bath additive preparation, 
in particular an oil bath preparation, in which the advantageous actions 
of the polyglycerol fatty acid ester mixture according to the invention 
are particularly shown to advantage. 
The bath additive preparation according to the invention, in particular an 
oil bath preparation, contains a polyglycerol fatty acid ester mixture of 
mono-, di- and polyesters of polyglycerols having a degree of 
polymerization of 2 to 8 and at least one saturated and/or unsaturated 
fatty acid, at least one oily or oil-containing component selected from 
the natural and synthetic, mineral, ethereal and fatty animal and 
vegetable oils, optionally a solvent or solvent mixture, and optionally 
further adjuvants and additives, and is characterized in that it 
comprises: 
10 to 60 wt-% of a polyglycerol fatty acid ester mixture as a water-soluble 
emulsifier and/or solubilizer, 
10 to 60 wt-% of an oil, oil mixture and/or oil component having cosmetic 
and/or therapeutic activity, and 
0 to 70 wt-% of water, 
the polyglycerol fatty acid ester mixture (relative to 100 parts by weight 
of the polyglycerol fatty acid ester mixture) containing 
20 to 65 wt-% of triglycerol fatty acid esters, 
20 to 50 wt-% of tetraglycerol fatty acid esters, and 
5 to 40 wt-% of higher polyglycerol fatty acid esters 
and containing no or only small amounts (less than 5 wt-%) of diglycerol 
fatty acid esters, and the fatty acid component consisting of one or more 
fatty acids selected from the saturated and/or unsaturated, branched 
and/or unbranched C.sub.6 - to C.sub.14 -fatty acids containing less than 
10 wt-% of fatty acids having more than 14 carbon atoms. 
The outstanding emulsifying and/or solubilizing action of the polyglycerol 
fatty acid ester mixture according to the invention preferably also proves 
very advantageous in bath additive preparations which contain oily or 
oil-containing substances which are naturally difficult to emulsify or 
solubilize. The excellent spontaneous emulsification power of the 
polyglycerol fatty acid ester mixture according to the invention is seen 
in particular when incorporating the bath additive preparation according 
to the invention into strongly diluted aqueous solutions, such as, for 
example, bath water, the oily or oil-containing component in, and/or on 
the surface of (spreading), the bath water being finely dispersed so that 
it can optimally achieve its cosmetic and/or therapeutic action. 
The bath additive composition according to the invention is not only 
physiologically acceptable and readily biodegradable, but it also has a 
skin-caring and skin-protecting, particularly an oil-restoring, effect - 
which also leads on high dilution of the bath additive preparation 
according to the invention in bath water to a pleasant feel to the skin 
after the bath and counteracts the tendency of the bath water to dry out 
the skin. 
Depending on the specific choice of the oil, oil mixture and/or oil 
component having a cosmetic and/or therapeutic effect, particular care 
properties and/or medicinal-therapeutic or pharmacological effects, such 
as, for example, healing, relieving, tranquilizing, relaxing, regenerating 
and/or vitalizing physiological actions, are incorporated in the bath 
additive preparation according to the invention. 
According to one preferred embodiment, the bath additive composition 
according to the invention contains 
15 to 50 wt-% of a polyglycerol fatty acid ester mixture, 
15 to 50 wt-% of an oil, oil mixture and/or oil component having cosmetic 
and/or therapeutic activity, and 
0.5 to 60 wt-% of water, 
the polyglycerol fatty acid ester mixture (relative to 100 parts by weight 
of the polyglycerol fatty acid ester mixture) containing 
22 to 32 wt-% of triglycerol fatty acid esters, 
39 to 49 wt-% of tetraglycerol fatty acid esters, and 
24 to 34 wt-% of higher polyglycerol fatty acid esters, 
and containing no or only small amounts (less than 3 wt-%) of diglycerol 
fatty acid esters and the fatty acid component consisting of one or more 
fatty acids selected from the saturated and/or unsaturated, branched 
and/or unbranched C.sub.8 - to C.sub.12 -fatty acids containing less than 
5 wt-% of fatty acids having more than 14 carbon atoms. 
As the fatty acid component in the polyglycerol fatty acid ester mixture 
according to the invention, bath additive preparations according to the 
invention preferably contain caprylic acid, capric acid, lauric acid, 
undecenoic acid, 2-ethylhexanoic acid or coconut fatty acid. It is also 
possible for these fatty acids to be present as mixtures with one another. 
Additional or particular properties can be incorporated in the 
polyglycerol fatty acid ester mixture according to the invention by means 
of the aforementioned compounds. These include, for example, either 
advantageous skin-care properties or, as in the case of undecenoic acid, 
an antimycotic action, which is advantageous for preserving the bath 
additive preparation. 
As an oil having a cosmetic effect, the bath additive preparation according 
to the invention preferably contains fatty vegetable oils, such as jojoba 
oil, soya oil, sesame oil, groundnut oil, sunflower oil, olive oil, palm 
oil, palm kernel oil, castor oil, cocoa oil, coconut oil, almond oil or 
wheatgerm oil. These oils may be employed individually or in mixtures with 
one another. 
In addition, the bath additive preparation according to the invention may 
contain cosmetic animal oils, preferably synthetic uropygial gland oil, 
which increases the hydrophobicity of the skin and which can be 
incorporated in the bath additive preparation according to the invention 
without formation of precipitates due to the excellent solubilizing 
capacity of the polyglycerol fatty acid ester mixture according to the 
invention. 
Particular pharmacological or medicinal-therapeutic properties are 
incorporated in the bath additive preparation according to the invention 
by using oils or oil mixtures having a corresponding medicinal or 
therapeutic action, preferably by addition of ethereal oils, such as 
rosemary oil, lavender oil, balm mint oil, sage oil, garlic oil, juniper 
berry oil, aniseed oil, cardamon oil, pimento oil, aniseed oil, caraway 
oil, lemon oil, orange oil, peppermint oil, camphor oil, clove oil, 
pine-needle oil or eucalyptus oil. These oils may be employed either 
individually or in mixtures with one another. 
As the oil and/or oil component having a cosmetic effect, the bath additive 
preparation according to the invention can furthermore contain natural or 
synthetic compounds, such as, preferably, isopropyl myristate, isopropyl 
palmitate, decyl oleate, 2-octyldodecanol, cetyl stearyl isononanoate, 
lanolin or cholesterol derivatives and caprylic/capric acid triglyceride, 
it being possible for these compounds to be employed on their own or in 
mixtures with one another and also to have a skin-caring and/or 
oil-restoring action. 
The aforementioned natural or synthetic, fatty vegetable and animal oils 
and also ethereal oils and oil components-can be mutually completely or 
partially replaced in the bath additive preparation according to the 
invention. However, they can also be completely or partially replaced in 
the bath additive preparation according to the invention by pharmaceutical 
or therapeutic mineral oils or oil mixtures, such as, for example, liquid 
paraffin. 
An additional perfuming effect can be incorporated in the bath additive 
preparation according to the invention by the addition of certain ethereal 
oils, preferably rose oil, jasmine oil, violet oil, mimosa oil, orange 
oil, neroli oil, patchouli oil, sandalwood oil or cinnamon oil and also by 
the addition of synthetic or natural perfume compositions, it being 
possible to employ these oils on their own or in mixtures with one 
another. A so-called scented bath is then obtained. 
Solutions of vegetable extracts, such as those of camomile, can be 
contained in the bath additive preparation as further therapeutic 
substances in order, for example, to relieve or to heal inflammatory 
processes on the skin and in the respiratory tract organs. 
The bath additive preparation according to the invention can also be 
formulated as a foam bath. To do this, foam-active agents are additionally 
incorporated, such as, for example, anionic surfactants, preferably alkyl 
ether sulfonates and sulfates, in particular sodium lauryl ether sulfate, 
in order to obtain a good foaming power even in the presence of 
significant amounts of oil or fat. 
As a solvent, the bath additive preparation according to the invention can 
contain water, preferably demineralized water, which optionally contains 
small amounts of water-soluble organic solvents which are acceptable in 
health terms. These are, for example, glycerol and/or lower alcohols, such 
as 1,2-propanediol, which can be employed as additional solubilizers and 
prevent turbidity in the bath additive preparation by means of 
flocculation of organic constituents. 
The use of small amounts of water as a solvent is particularly advantageous 
if the bath additive preparation of emulsifying or solubilizing 
polyglycerol fatty acid ester mixture according to the invention and the 
oily or oil-containing component forms a turbid solution. An optically 
clear solution is then obtained by the addition of water. 
The polyglycerol fatty acid ester mixture according to the invention 
exhibits its superiority compared to commercially available products in 
particular with respect to its excellent solubilizing power in 
water-containing oil bath preparations. 
The polyglycerol fatty acid ester mixture according to the invention can 
additionally be combined with a further polyglycerol fatty acid ester 
mixture as a solubilizer. Particularly suitable for this purpose is a 
polyglycerol caprate or a polyglycerol cocoate which are preferably 
prepared according to our own unpublished Patent Application P 41 05 
305.2. 
With a higher content of vegetable oils, in particular in a 
water-containing preparation, it may be advantageous to protect the bath 
additive preparation according to the invention from microbial decay. 
Compounds such as benzoates, benzoic acid derivatives, sorbates, 
microbiologically active phenols, such as 2,6-di-tert-butyl-methylphenol, 
and dioxanes, such as 5-bromo-5-nitro-1,3-dioxane, can be employed as 
bacteriostatic or bactericidal preservatives. 
The bath additive preparation according to the invention can be provided 
with antioxidants, such as tocopherols, in particular vitamin E, and/or 
butylhydroxytoluene, against oxidative decomposition. 
The preservatives are employed in the bath additive preparation according 
to the invention in customary amounts. 
Further additives or auxiliaries which can be contained in the bath 
additive preparation according to the invention are pH regulators, 
thickeners or viscosity regulating agents, such as polyglycols, propylene 
glycol, ethanol, isopropanol, sodium polyacrylate and/or inorganic salts, 
preferably sodium chloride, complexing agents for masking metal ions, 
humectants, such as diglycerol, and colorants. 
The bath additive preparation according to the invention displays its 
advantageous action in particular in an amount of from 15 to 30 ml to 
about 200 liters of bath water. 
The bath additive preparation according to the invention is prepared by 
simple mixing of the constituents in appropriate mixing devices, the 
sequence of the addition of the individual components being arbitrary. 
The present invention additionally relates to a process for the preparation 
of a polyglycerol fatty acid ester mixture of mono-, di- and polyesters of 
polyglycerols having a degree of polymerization of 2 to 8 and at least one 
saturated and/or unsaturated fatty acid, the process being characterized 
in that a polyglycerol which (relative to 100 parts by weight of 
polyglycerol) contains 
20 to 65 wt-% of triglycerol, 
20 to 50 wt-% of tetraglycerol and 
5 to 40 wt-% of higher polyglycerols 
and contains no or only small amounts (less than 5 wt-%) of diglycerol, is 
reacted with one or more fatty acids, selected from the saturated and/or 
unsaturated, branched and/or unbranched C.sub.6 - to C.sub.14 -fatty 
acids, the fatty acid or the fatty acid mixture containing less than 10 
wt-% of fatty acids having more than 14 carbon atoms, in a molar ratio of 
the polyglycerol to the fatty acid or to the fatty acid mixture of 
4:1 to 1 :1, preferably 
2.5 : 1 to 1.5 :1 
in the presence of at least one catalyst, preferably an acidic catalyst, 
and at reduced pressure, by first heating the reaction mixture to 
140.degree. C., preferably 145.degree. C., and reducing the pressure to 
600 mbar, preferably 500 mbar, and then heating the reaction mixture in a 
temperature range from 
140.degree. to 220.degree. C., preferably 
145.degree. to 190.degree. C., 
stepwise or continuously, controlled by means of a temperature program, and 
at the same time reducing the pressure stepwise or continuously, 
controlled by means of a pressure program, 
from 600 to 10 mbar, preferably 
from 500 to 20 mbar, 
the resultant water of reaction being continuously removed by distillation 
and, upon attaining an acid number of &lt;3, the resulting polyglycerol fatty 
acid ester mixture being cooled and optionally worked up and/or purified. 
Particularly preferably, a molar ratio of the polyglycerol to the fatty 
acid or to the fatty acid mixture of 2:1 is set in the process according 
to the invention. 
The process according to the invention allows the preparation of 
polyglycerol fatty acid ester mixtures of defined hydrophilicity by a 
simple and economical reaction procedure in which a constant quality and 
reproducible composition of the polyglycerol fatty acid ester mixture is 
guaranteed. 
According to a preferred embodiment of the process according to the 
invention, a polyglycerol is employed which (relative to 100 parts by 
weight of polyglycerol) contains 
22 to 32 wt-% of triglycerol, 
39 to 49 wt-% of tetraglycerol and 
24 to 34 wt-% of higher polyglycerols 
and contains no or only small amounts (less than 3 wt-%) of diglycerol. 
As used herein the term "polyglycerol" refers generally to mixtures 
polyglycerols or glycerol oligomers of varying chain length. 
The polyglycerol or polyglycerol mixture employed according to the 
invention is preferably prepared from the product mixture (polyglycerol) 
obtained according to German Patent No. DE 3,721,003 or according to 
Published German Application No. DE 3,410,520, by working up these 
polyglycerol mixtures by distillation, whereby diglycerol, in particular, 
is removed. 
According to one preferred embodiment, a fatty acid or a fatty acid 
mixture, selected from the saturated and/or unsaturated, branched and/or 
unbranched C.sub.8 - to C.sub.2 -fatty acids containing less than 5 wt-% 
of fatty acids having more than 14 carbon atoms is employed in the process 
according to the invention. 
According to a further preferred embodiment of the process according to the 
invention, the resulting polyglycerol fatty acid ester mixture is purified 
and/or worked up in order to at least partially remove unreacted 
polyglycerol from the product of the process; this being advantageous or 
necessary for certain applications. 
To achieve this, the polyglycerol fatty acid ester mixture obtained by the 
process according to the invention is cooled to 30.degree. to 110.degree. 
C., preferably 60.degree. to 80.degree. C., and subsequently subjected to 
an extraction treatment by treating the polyglycerol fatty acid ester 
mixture with an organic chemical solvent or solvent mixture and then 
extracting polyglycerol with water, preferably in a single extraction 
step, an amount by weight of an inorganic and/or organic, basic compound 
corresponding to the acid number of the polyglycerol fatty acid ester 
mixture and/or at least equivalent to the amount of catalyst additionally 
being added in the first extraction step, and the organic phase remaining 
after the extraction being freed from the organic solvent employed and the 
residual water content by distillation, preferably vacuum distillation or 
vacuum evaporation. 
The organic chemical solvent or solvent mixture employed in the extraction 
treatment desirably has a water absorption power of less than 30 wt-%, 
preferably less than 20 wt-% (relative to 100 parts by weight of the 
organic chemical solvent or solvent mixture), and/or forms an azeotropic 
mixture with water during the distillation or in the gas phase. 
One organic chemical solvent which has these properties is ethyl acetate. 
If ethyl acetate is used in the extraction process, it is preferably 
employed as a water-saturated organic phase. Other organic chemical 
solvents which can be used according to the invention include, inter alia, 
butanol and/or toluene. 
The neutralization of the catalyst is preferably carried out according to 
the invention using sodium hydroxide, in particular using aqueous sodium 
hydroxide solution, the alkaline compound or solution being added in the 
first extraction step to the organic chemical solvent or solvent mixture 
and/or to the water phase. 
Other suitable neutralizing agents include alkali metal carbonates, 
preferably sodium carbonate and/or potassium carbonate, and/or a basic ion 
exchanger, which in each case are added to the organic chemical solvent or 
solvent mixture and/or to the water phase in the first extraction step. 
If the polyglycerol fatty acid ester mixture prepared according to the 
invention is allowed to stand before further processing and/or 
purification for more than 0.5 hour, preferably 1 to 10 hours, unreacted 
contents of polyglycerol can optionally be precipitated and separated from 
the product mixture. 
The constant quality of the final product, the defined composition of the 
ester mixture and the reproducibility of the reaction result are obtained 
in this process in particular by means of the controlled reaction sequence 
with respect to heating and simultaneous pressure reduction in the 
reaction mixture and also by the exact maintenance of specific pressure 
and temperature ranges. 
The reaction sequence of the process according to the invention can be 
carried out continuously, controlled by means of an appropriate 
temperature and pressure program controller, or batchwise by means of 
stepwise heating and pressure reduction. 
In this regard, it has been found to be advantageous to carry out the 
heating of the reaction mixture in the temperature range from 140.degree. 
to 220.degree. C., preferably 145.degree. to 190.degree. C., and to carry 
our the pressure reduction from 600 to 10 mbar, preferably from 500 to 20 
mbar, in a time interval of from 2 to 6 hours, preferably 3 to 4 hours. 
According to a further preferred embodiment of the process according to the 
invention, the heating of the reaction mixture in the temperature range 
from 140.degree. to 220.degree. C., preferably 145.degree. to 190.degree. 
C., is carried out stepwise in 3 to 6 steps, preferably 4 or 5 steps. 
Corresponding to this, the reduction of the pressure from 600 to 10 mbar, 
preferably 500 to 20 mbar, can be performed stepwise in a specified number 
of steps, preferably in 3 to 6 steps, in particular 4 or 5 steps. 
The esterification reaction in the process according to the invention is 
carried out in the presence of a catalyst, preferably in the presence of 
an acidic compound containing sulfonic acid groups, such as, for example, 
dodecylbenzenesulfonic acid or other alkyl-benzenesulfonic acids. 
According to one embodiment, this acidic catalyst is employed in 
combination with a second acidic compound having catalytic and reducing 
action. A suitable compound in this respect is hypophosphorous acid. 
According to a further advantageous embodiment of the process according to 
the invention, the reaction mixture is reacted in the presence of an inert 
gas, preferably nitrogen. 
The invention furthermore relates to the use of the polyglycerol fatty acid 
ester mixture according to the invention as an emulsifier, solubilizing 
agent, dispersing agent, wetting agent and/or oil-restoring agent in 
cosmetic, pharmaceutical or chemicotechnical preparations. 
The polyglycerol fatty acid ester mixture according to the invention has 
many uses. It is preferably used for the emulsification and/or dispersion 
and/or solubilization of natural or synthetic, ethereal, mineral, fatty 
animal or vegetable oils. It is particularly outstandingly suitable for 
preparing oil-containing bath additives, preferably bath oils or oil 
baths. 
In addition, the polyglycerol fatty acid ester mixture according to the 
invention is used as a skin-care additive and/or detergent, cleaning agent 
or body shampoo, shower gel or shower composition, foam bath composition, 
liquid hand-cleaning agent or hair shampoo, since in addition to the 
surface-active property it also has a mild cleaning action as well as an 
oil-restoring effect and gives a pleasant feel to the skin during and 
after the cleaning process. 
Other areas of use for the polyglycerol fatty acid ester mixture according 
to the invention are foodstuffs and medicaments, ointments, pharmaceutical 
and cosmetic preparations of any type where the polyglycerol fatty acid 
ester mixture acts as a solubilizing agent and/or emulsifier or dispersing 
agent and/or wetting agent. Its many uses result, inter alia, from the 
fact that, on the one hand, the polyglycerol fatty acid ester mixture 
according to the invention is easily processable, and on the other hand, 
it is neutral or beneficial to the skin and body. Cosmetic preparations 
using the polyglycerol fatty acid ester mixture according to the invention 
impart an optimum feeling of care. When used on the skin, e.g. in cosmetic 
preparations, skin disinfectants, ointments, embrocations and the like, 
the polyglycerol fatty acid ester mixture according to the invention has 
an oil-restoring action. 
In addition, the polyglycerol fatty acid ester mixture according to the 
invention is especially suitable for industrial applications, preferably 
as an emulsifier in drilling oils or drilling fluids as well as 
lubricating oils, and also as a wetting and/or dispersing agent in 
industrial cleaning agents or as an emulsifier and/or dispersing agent in 
dye preparations, preferably in disperse dyes, or preservatives for 
buildings, in particular protective coatings and glazes for wood. 
The polyglycerol fatty acid ester mixture according to the invention can 
additionally be employed as a water-soluble lubricant in chemicotechnical 
preparations. 
The polyglycerol fatty acid ester mixture according to the invention can be 
combined without difficulty with other additives or adjuvants in 
ready-to-use formulations. Electrolytes and/or other surfactants and also 
solvents and/or diluents can preferably additionally be employed in 
detergents, cleaning agents and/or body shampoos. In addition, the 
polyglycerol fatty acid ester mixture according to the invention can be 
used together with preservatives, perfuming compositions, colorants, 
pharmaceutically active compounds, pH-adjusting compositions for pH 
regulation, complexing agents for masking metal ions, skin-care agents 
and/or thickening agents and other compounds such as colloids, active 
disinfectants, compounds having fungicidal, insecticidal and/or 
antibacterial activity, corrosion inhibitors, etc.

The following preparative examples and use examples are intended to 
illustrate the invention in further detail with out restricting its scope. 
Example 1: 
Preparation of polyglycerol caprate. 
A mixture of 2608 g of polyglycerol (average molecular weight: about 326 
g/mole; consisting of about 30% triglycerol, about 45% tetraglycerol, 
about 17% pentaglycerol, and about 8% higher oligomers), 688 g=4 moles of 
capric acid, 5.6 g of dodecylbenzenesulfonic acid and 2.2 g of 
hypophosphorous acid was heated up to a maximum of 155.degree. C. at 400 
to 40 mbar during the course of about 3 h with stirring and simultaneous 
passage of inert gas in a 4-liter four-neck flask which was provided with 
a stirrer, water separator, thermometer and gas inlet tube, the water of 
reaction being continuously removed by distillation. On attaining an acid 
number of &lt;2, the reaction mixture was cooled down to about 65.degree. C. 
and unreacted contents of polyglycerol were removed as follows: 
The reaction mixture was dissolved in ethyl acetate (half the amount by 
volume) and extracted with water. The amount of sodium hydroxide solution 
corresponding to the acid number was added to the water. The amount of 
water used for extraction was about 50% by volume of the ester employed. 
The total of the extracted contents of polyglycerol after removal of the 
solvent by distillation was about 20 wt-% of the crude ester employed. The 
organic phase remaining after the extraction was evaporated in vacuo 
(residual content of water: 10 wt-%). 
Characterizing data: 
Acid number: &lt;2 
Hydrolysis number: 75-85 
HLB: 14.3 
Example 2: 
Preparation of polyglycerol laurate. 
A mixture of 886 g of polyglycerol (average molecular weight: about 326 
g/mole; consisting of about 30% triglycerol, about 45% tetraglycerol, 
about 17% pentaglycerol, and about 8% higher oligomers), 272 g=1.36 moles 
of lauric acid, 2.8 g of dodecylbenzenesulfonic acid and 1.1 g of 
hypophosphorous acid was heated up to a maximum of 155.degree. C. at 400 
to 40 mbar during the course of about 3 hours with stirring and 
simultaneous passage of inert gas in a 2-liter four-neck flask which was 
provided with a stirrer, water separator, thermometer and gas inlet tube, 
the water of reaction being continuously removed by distillation. On 
attaining an acid number of &lt;2, the reaction mixture was cooled down to 
about 70.degree. C. and unreacted contents of polyglycerol were removed as 
follows: 
The reaction mixture was dissolved in ethyl acetate (half the amount by 
volume) and extracted with water. The amount of sodium hydroxide solution 
corresponding to the acid number was added to the water. The amount of 
water used for extraction was about 50% by volume of the ester employed. 
The total of the extracted contents of polyglycerol after removal of the 
solvent by distillation was about 31 wt-% of the crude ester employed. The 
organic phase remaining after the extraction was evaporated in vacuo. 
Characterizing data: 
Acid number: 0.9 
Hydrolysis number: 98.4 
HLB: 13.0 
Example 3: 
Preparation of polyglycerol caprylcaprate. 
A mixture of 2457 g of polyglycerol (average molecular weight: about 273 
g/mole; consisting of about 4% diglycerol, about 62% triglycerol, about 
24% tetraglycerol, about 7% pentaglycerol, and about 3% higher oligomers), 
706 g=4.5 moles of caprylic/capric acid mixture, 6.3 g of 
dodecylbenzenesulfonic acid and 2.5 g of hypophosphorous acid was heated 
up to a maximum of 155.degree. C. at 400 to 40 mbar during the course of 
about 3 hours with stirring and simultaneous passage of inert gas in a 
4-liter four-neck flask which was provided with a stirrer, water 
separator, thermometer and gas inlet tube, the water of reaction being 
continuously removed by distillation. Upon attaining an acid number of &lt;2, 
the reaction mixture was cooled down to about 70.degree. C., and unreacted 
polyglycerol was removed as follows: 
The reaction mixture was dissolved in ethyl acetate (half the amount by 
volume) and extracted with water. An amount of sodium hydroxide solution 
corresponding to the acid number was added to the water. The amount of 
water used for extraction was about 50% by volume of the ester employed. 
The total amount of extracted polyglycerol after removal of the solvent by 
distillation was about 25 wt-% of the crude ester employed. The organic 
phase remaining after the extraction was evaporated in vacuo. 
Characterizing Data: 
Acid number: 1.0 
Hydrolysis number:. 108.9 
HLB: 12.3 
Examples of use of Polyglycerol Fatty Acid ester mixtures prepared 
according to the invention 
Example I 
Oil/water body lotion containing polyglycerol laurate of the invention as 
an oil/water emulsifier. 
A composition was prepared comprising the following ingredients: 
1.5 wt-% polyglycerol laurate according to the invention (Prepn. Example 2) 
0.5 wt-% sodium polyacrylate 
5.0 wt-% liquid paraffin, viscous, GB 
4.0 wt-% acetylated lanolin 
6.0 wt-% cetyl stearyl isononanoate 
4.0 wt-% diglycerol 
0.05 wt-% preservative 
0.3 wt-% perfume 
78.65 wt-% water (completely demineralized) 
The product was a white, stable emulsion with very good absorption power 
and outstanding feel to the skin. 
Centrifuge test 20 min. 5000 rpm: no separation Viscosity, measured with 
Haake viscometer, VT 181, MV DIN/32 at 20.degree. C.: 3500 mPa.s 
Example II 
Oil/water body lotion containing natural or identical-to-natural raw 
materials and the polyglycerol laurate of the invention as an oil/water 
emulsifier. 
A composition was prepared comprising the following ingredients: 
2.0 wt-% polyglycerol laurate according to the invention (Prepn. Example 2) 
0.5 wt-% sodium polyacrylate 
6.0 wt-% wheatgerm oil 
6.0 wt-% cetyl stearyl isooctanoate (synthetic uropygial gland oil) 
7.0 wt-% caprylic/capric acid triglyceride 
4.0 wt-% diglycerol 
0.05 wt-% preservative 
0.3 wt-% perfume 
74.15 wt-% water (completely demineralized) 
The product was a slightly yellow, lustrous, stable emulsion. 
Centrifuge test, 20 min. @ 5000 rpm: no separation 
viscosity measured using Haake viscometer VT 181, MV DIN/32 at 20.degree. 
C.: 3000 mPa.s 
Example III 
Rosemary bath oil. 
A composition was prepared comprising the following ingredients: 
27 wt-% rosemary oil 
33 wt-% polyglycerol caprate according to the invention (Prepn. Example 1) 
40 wt-% water (completely demineralized) 
The product was a clear, low-viscosity oil having good emulsifying power in 
warm water and good oil-restoring capacity on the skin. 
Example IV 
Pine-needle bath oil. 
A composition was prepared comprising the following ingredients: 
20 wt-% pine-needle oil 
45 wt-% polyglycerol caprylcaprate according to the invention (Prepn. 
Example 3) 
35 wt-% water (completely demineralized) 
The product was a clear, low-viscosity oil having good emulsifying power in 
warm water and good oil-restoring capacity on the skin. 
Example V 
Rosemary bath oil containing water. 
A composition was prepared comprising the following ingredients: 
20 wt-% rosemary oil 
50 wt-% polyglycerol caprate according to the invention (Prepn. Example 1) 
30 wt-% water (completely demineralized) 
The product was a clear, low-viscosity oil having good emulsifying power in 
warm water and good oil-restoring capacity on the skin. 
Example VI 
Spreading oil bath preparation having high skin-care action. 
A composition was prepared comprising the following ingredients: 
20 wt-% polyglycerol caprate according to the invention (Prepn. Example 1) 
20 wt-% polyglycerol caprate (Prepn. DE 4,105,305.2) 
20 wt-% isopropyl myristate 
31 wt-% liquid paraffin GP, viscous 
5 wt-% perfume oil 
4 wt-% water (completely demineralized) 
Example VII 
Spontaneously emulsifying bath oil with skin-care properties. 
A composition was prepared comprising the following ingredients: 
25 wt-% polyglycerol caprate according to the invention (Prepn. Example 1) 
17 wt-% polyglycerol cocoate (Prepn. DE 4,105,305.2) 
33 wt-% isopropyl myristate 
20 wt-% jojoba oil 
5 wt-% perfume oil. 
The foregoing description and examples have been set forth merely to 
illustrate the invention and are not intended to be limiting. Since 
modifications of the disclosed embodiments incorporating the spirit and 
substance of the invention may occur to persons skilled in the art, the 
invention should be construed to include everything within the scope of 
the appended claims and equivalents thereof.