Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
1997-10-24
2001-10-23
Lovering, Richard D. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C424S401000, C510S138000, C510S416000, C514S937000
Reexamination Certificate
active
06306916
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a pearlescent concentrate with newtonian flow behavior in the form of a low-viscosity aqueous dispersion containing 10 to 40% by weight of pearlescing components.
Aqueous preparations of surfactants and cosmetic formulations can be given a pearlescent, aesthetically pleasing appearance by incorporation of substances which, after cooling, precipitate in the form of fine pearlescent crystals and remain dispersed in the preparations. Suitable pearlescing agents are, for example, the mono-, di- and optionally triesters of ethylene glycol or glycerol with C
14-22
fatty acids, oligomeric alkylene glycol esters of this type, for example PEG-3-distearates, fatty acids and monoalkanolamides of fatty acids.
It is also known that the pearlescing agents mentioned can be stably dispersed in water or in aqueous emulsifier solutions and that the concentrated pearlescing dispersions obtained in this way can be added without heating to the preparations to be given a pearlescent appearance so that there is no need for the heating and cooling otherwise necessary for incorporation to form the pearlescent crystals.
One of the problems involved in the production and use of pearlescent concentrates concerns their flowability and pumpability. Both are often seriously limited, above all where the pearlescing components and emulsifiers are present in high concentrations. Alternatively, the concentrates may even assume the form of mixtures which do not flow and also cannot be pumped by conventional equipment.
2. Discussion of Related Art
Accordingly, it was proposed in German patent applications DE 38 43 572 and DE 41 03 551 to reduce the viscosity of pearlescent concentrates by addition of low molecular weight polyhydric alcohols and thus to make them flowable and pumpable.
International patent application WO 94/24248 discloses pearlescing agents based on alkyl polyglycoside/betaine surfactants which also contain glycols.
Although pearlescent concentrates sufficiently pumpable and flowable for conventional processing can be obtained in accordance with the teachings of these documents, these products are still not entirely satisfactory. The reason for this lies in the pronounced non-Newtonian or thixotropic behavior of the concentrates.
Thus, a thixotropic increase in viscosity is observed, in particular after prolonged storage. In addition, the yield point means that a more or less thick layer of product always remains behind on the walls of the storage container and can only be removed with immense effort or in the course of cleaning operations. In the latter case, therefore, part of the product is lost, i.e. is not available for processing. Finally, the pressure loss involved in the pumping of non-newtonian liquids is distinctly higher than for newtonian liquids which means that the pumping equipment has to meet increased performance requirements, particularly at the beginning of pumping.
Accordingly, there is still a need for pearlescent concentrates which are distinguished both by low viscosities, i.e. pumpability or flowability, and in particular by newtonian viscosity behavior.
DESCRIPTION OF THE INVENTION
It has now surprisingly been found that low-viscosity pearlescent concentrates with the viscosity behavior of newtonian liquids can be formulated providing alkyl polyglycosides are used as emulsifiers. This viscosity behavior only occurs if the emulsifiers used belong predominantly to the class of alkyl polyglycosides. For example, even small quantities of emulsifiers containing —COO
—
and —OSO
3
—
groups generally lead to pronounced non-newtonian behavior of the pearlescent concentrates.
Accordingly, the present invention relates to a pearlescent concentrate in the form of an aqueous dispersion containing 10 to 40% by weight of pearlescing components and 15 to 55% by weight of emulsifiers, characterized in that the emulsifiers are alkyl polyglycosides corresponding to general formula (I):
RO—(Z)
x
(I)
in which R is an alkyl group containing 6 to 22 carbon atoms, Z is a mono- or oligosaccharide, x is a number of 1.1 to 5, or addition products thereof with 1 to 10 molecules of ethylene oxide and/or propylene oxide and in that the pearlescent concentrate is free from emulsifiers containing —COO
—
and —OSO
3
—
groups.
In the context of the invention, pearlescing components are understood to be fusible fats or waxes which, on cooling of their aqueous solutions or emulsions at temperatures of around 30 to 90° C., crystallize out in the form of fine pearlescent crystals.
These fusible fats or waxes include
(A1) esters corresponding to formula (II):
R
1
—(OC
n
H
2n
)
x
—OR
2
(II)
in which R
1
is a linear fatty acyl group containing 14 to 22 carbon atoms, R
2
is hydrogen or has the same meaning as R
1
, n=2 or 3 and x is a number of 1 to 4,
(A2) monoalkanolamides corresponding to general formula (III):
R
3
—CO—NH—X (III)
in which R
3
is an alkyl group containing 8 to 22 and, more particularly, 8 to 18 carbon atoms and X is a group —CH
2
—CH
2
—OH, a group —CH
2
—CH
2
—CH
2
—OH or a group —C(CH
3
)
2
—OH,
(A3) linear saturated fatty acids containing 14 to 22 carbon atoms,
(A4) mono-, di- and triesters of glycerol with linear saturated fatty acids containing 12 to 22 carbon atoms and
(A5) &bgr;-ketosulfones corresponding to general formula (IV):
in which R
4
is an alkyl or alkenyl group containing 11 to 21 carbon atoms, R
5
and R
6
are hydrogen atoms or together represent an ethylene group which forms a tetrahydrothiophene dioxide ring with the group positioned between R
5
and R
6
.
Suitable esters (A1) corresponding to the general formula R
1
(OC
n
H
2n
)
x
OR
2
are, for example, the monoesters and diesters of ethylene glycol and propylene glycol with higher fatty acids, for example with palmitic acid, stearic acid or behenic acid, or the diesters of diethylene glycol or triethylene glycol with such fatty acids. Mixtures of monoesters and diesters of the glycols mentioned with fatty acid mixtures, for example with hydrogenated tallow fatty acid, palm oil fatty acid or with the saturated C
14-18
fatty acid fraction of tallow fatty acid, are also suitable. The ethylene glycol monoesters and/or diesters of palmitic and/or stearic acid are particularly suitable.
Preferred monoalkanolamides (A2) are the monoethanolamides. These compounds may contain single alkyl groups. However, it is standard practice to produce the alkanolamides from fatty acid mixtures from natural sources, for example cocofatty acids, so that corresponding mixtures of alkyl groups are present.
Suitable linear fatty acids (A3) are, for example, palmitic acid, stearic acid, arachic acid or behenic acid, although technical fatty acid cuts consisting entirely or predominantly of fatty acids containing 16 to 22 carbon atoms, for example the palmitic/stearic acid fractions obtained from tallow fatty acid or palm oil fatty acid by removal of the fatty acids liquid at +5° C. or the palmitic/stearic acid fractions obtainable by hydrogenation of tallow fatty acid or palm oil fatty acid, may also be used.
The glycerol esters (A4) suitable for use in the teaching according to the invention include the mono-, di- and—in particular—triesters with lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid and with mixtures of these fatty acids.
The &bgr;-ketosulfones (A5) corresponding to general formula (IV) have the advantage over known ethylene glycol monoesters and diesters that the pearlescence of the formulations has higher thermal stability, i.e. the formulations retain their pearlescence for several hours on heating to temperatures above 50° C. and, in some cases, even to temperatures above 70° C. Further information on the &bgr;-ketosulfones mentioned can be found in German patent application DE 35 08 051.
The pearlescent concentrates according to the invention may contain both exclusively representatives of one of these classes of compounds and mixtures of representatives of several
Ansmann Achim
Kawa Rolf
Strauss Gabriele
Drach John E.
Henkel Kommanditgesellschaft auf Aktien
Lovering Richard D.
Murphy Glenn E. J.
Trzaska Steven J.
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