Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2000-03-08
2001-08-21
Koslow, C. Melissa (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031120, C106S243000
Reexamination Certificate
active
06277182
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to pigment-containing oil-based gel materials, colored pencils containing them and a process for the production of colored pencils.
Pigment-containing oil-based gel materials are dispersed systems which consist of a skeleton of the gel-forming component with an oil component incorporated therein. The gel material furthermore contains pigments for coloring. Such materials are suitable for applying colors in many areas. Suitable principal fields of use for pigmented gel materials are in colored materials for drawing and painting and the area of decorative cosmetics, where they can be used in many forms, inter alia for make-up, creamy eye shadows, lipsticks and eyeliner and eyebrow pencils. In particular, such pigment-containing gel materials can be used for producing cosmetic pencils or sticks.
Materials used for drawing, painting or make-up should be capable of being easily applied but should be well retained after application and should as far as possible be water-resistant, in the case of cosmetics pencils also tear-resistant, and transfer-resistant, i.e. should not stain other surfaces and articles and should not bleed from the area of application.
Known formulations for pencils or sticks are based on a mixture of waxes and oils which is colored with pigments. Thus, pencil or stick formulations composed of natural or mineral waxes, natural or synthetic oils or mineral oils and conventional additives, such as lanolin or lanolin derivatives, are described, for example, for lipsticks or eye shadow pencils. As a rule, these formulations are thixotropic systems which liquefy under the shear forces occurring during application and thus permit gentle application.
In the area of cosmetics, gel-like mixtures have predominantly been used to date for deodorant and antiperspirant sticks. They contain a considerable proportion of volatile silicone oils, such as cyclomethicone or dimethicone, or hydrocarbon oils, such as isoparaffin. These gels have the advantage that they can be readily applied but the disadvantage that they have no mechanical load capacity. For deodorant sticks, the advantage of easy application predominates whereas, owing to the shape of the sticks, stability is not so important. Deodorant sticks have a large diameter in relation to their length and the requirements with respect to the strength are not very high owing to the composition of the sticks. It has been found that materials which are suitable as deodorant sticks can be shaped into relatively thin leads only to a limited extent and in particular, since the material is too soft and unstructured, can be removed from the mold only with great difficulties or not at all.
Attempts have also been made to prepare oleogels containing candelilla wax and to shape them into leads. Owing to its gloss, candelilla wax is popular for lipsticks and eye shadow pencils. However, it has been found that the known oleogels have an insufficient oil-binding capacity, so that phase separation occurs and the oil contained in the material migrates into the environment. This impairs the aesthetic appearance of the pencil. Moreover, the loss of oil results in the sticks losing their elasticity and becoming brittle. In addition, it has been found that, as a result of the diffusion, evaporation or migration of the oil, the leads produced from the material shrink to such an extent that, when an attempt is made to produce colored pencils, leads inserted into wood slip out of the wood sleeves after a short time.
It is an object of the present invention to eliminate the disadvantages described above and to provide an oil-based gel material which has a high oil-binding capacity and which is suitable for being processed to give leads for pencils, in particular cosmetic pencils. It is a further an object of the invention to provide a material whose texture is stable and which as far as possible is water- and tear-resistant and is transfer-resistant, i.e. does not stain surfaces or articles after application. In addition, the application properties of the material should be good, i.e. it should be capable of being applied up to about 40° C. without deforming or smearing but should also not be too hard. For cosmetics pencils, it is moreover desirable for the gel material to be composed of only a few, cosmetically acceptable components. Moreover, the material should be capable of being shaped by casting or extrusion.
SUMMARY OF THE INVENTION
The foregoing objects are achieved by the present invention by providing a pigmented oil-based gel material which contains 0.1 to 25% by weight of a hydroxy-fatty acid having 10 to 20 C atoms, 0.1 to 30% by weight of C
30-45
-alkylmethicone, 1to 70% by weight of an oil component and 0.1 to 50% by weight of pigments.
DETAILED DESCRIPTION
Surprisingly, it has been found that a combination of a hydroxy-fatty acid with C
30-45
-alkylmethicone forms an outstanding matrix for binding oil components and gives a gel material which has excellent properties and can be very readily shaped by extrusion and casting. The four main components give a structured material which shows no phase separation even under thermal stress up to 45° C. C
30-45
-alkylmethicone, together with the hydroxy-fatty acid, forms a stable matrix which permanently and strongly binds the oil and the pigments. In addition, the material is given excellent thermal stability. This makes it possible to process the material at elevated temperatures and to store it without cooling.
One component, essential to the invention, of the gel material is the hydroxy-fatty acid, which has a gel-forming effect on the structure. It is a fatty acid having 10 to 20 C atoms, which carries at least one hydroxyl group, preferably in the chain and not as a terminal group. It is preferably a C
16
-hydroxy-fatty acid, and 12-hydroxystearic acid is particularly preferably used owing to its ready availability. The hydroxy-fatty acid is contained in the material in a proportion of 0.1 to 25% by weight, based on the material formed from pigment, methicone, oil and fatty acid. Below 0.1% by weight, no effect is detectable. A proportion of more than 25% by weight results in the proportion of the other structure-forming components decreasing to such an extent that a stable structure is difficult to obtain. Preferably, the hydroxy-fatty acid is used in an amount of 1 to 20% by weight. Particularly good results are obtained with a proportion of 2 to 15% by weight.
The other component important for the structure is C
30-45
-alkylmethicone. “C
30-45
-alkylmethicone” is the INCI name for a silicone resin which comprises long-chain alkyl radicals and has waxy properties and is commercially available under this name. This component contributes substantially to the advantages achieved with the gel material according to the invention. It has been found that, when other silicone resins, e.g. stearyl-dimethicone, or natural waxes, e.g. candelilla wax, are used, the oil-binding capacity is not sufficient for keeping oil components in a stable structure, and is also not capable of doing so in combination with a hydroxy-fatty acid. C
30-45
-alkylmethicone is present in the gel material according to the invention in a proportion of 0.1 to 30% by weight. With an amount of less than 0.1% by weight, the advantageous properties cannot be achieved. The addition of more than 30% by weight leads to hard, brittle materials having undesired application properties. The C
30-45
-alkylmethicone is preferably used in an amount of 1 to 30% by weight, particularly good results being obtained with a proportion of 5 to 20% by weight.
A further essential ingredient of the gel material according to the invention is the oil component. The oil component may comprise vegetable, animal, mineral or synthetic fat and/or oil and wax. Thus, inter alia, oils, fats, fatty oils, paraffins and vaseline are suitable for the present invention. All of these components are bound by the combination, according to the invention, of hydroxy-fatty acid and C
30-45
-alkylmethicone. The more
Lebok Simona
Winkler Wolfgang
Zarling Claudia
Bachman & LaPointe P.C.
Faison Veronica F.
Koslow C. Melissa
Schwan-STABILO Cosmetics GmbH & Co.
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