Drug – bio-affecting and body treating compositions – Dentifrices
Reexamination Certificate
1997-05-12
2001-11-13
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Dentifrices
C424S400000, C424S040000
Reexamination Certificate
active
06315986
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to aesthetically pleasing pleasant tasting multicomponent dentifrices and more particularly to a striped toothpaste or gel wherein there is substantially no colorant bleeding between dentifrice components.
2. The Prior Art
Aesthetic effects have been acknowledged to play an important role in consumer acceptance of many products. In many cases, ornamental effects have been used to distinguish particular products in the marketplace and to identify products having particular distinctive properties. In the dentifrice field, toothpastes and gels which have incorporated therein contrasting colored stripes are known. Such stripes provide an aesthetic effect which the user finds pleasing and promotes the use of the dentifrice, particularly by children.
A major problem impacting the aesthetic appearance of striped toothpaste is the bleeding or migration of color from one component into another. This is especially severe if one colored component is applied to the surface of a white base. For this reason, a colorant that exhibits substantially no visible bleeding is required.
Striped dentifrice products containing water-soluble dyes are known in the prior art as for example, as disclosed in U.S. Pat. Nos. 4,358,437, 4,568,534, and 4,487,757. A disadvantage to the use of water-soluble dyes enumerated in these patents is that visible bleeding is observed.
U.S. Pat. Nos. 3,957,964, 3,929,988, 4,071,614 and 4,348,378 disclose dentifrices containing encapsulated ingredients such as flavors whereby such ingredients are maintained substantially separate from other dentifrice ingredients during manufacture and storage, while subsequently releasing the encapsulated ingredients into the dentifrice during tooth brushing.
It is also known to the art, e.g., U.S. Pat. No. 4,202,878 to encapsulate water insoluble dyes in capsules wherein the shell material is formed from non-toxic naturally occurring waxes such as carnauba wax, candelella wax, castor wax, paraffin wax and bayberry wax. Although encapsulation of the dyes in these natural waxes overcome dye migration and bleeding, waxes such as natural paraffin wax, have been found to have the drawback, that the wax encapsulated dye when incorporated in a dentifrice composition produces an undesirable, waxy-plastic-like taste when stored at room temperature and during accelerated aging conditions, as for example, 6 weeks at 50° C.
Accordingly, there is a need for a colorant composition useful in the striping of aqueous based dentifrices which will essentially eliminate visible colorant bleeding and which does not suffer from the limitations and problems of the prior art.
SUMMARY OF THE INVENTION
By analyzing data on the temperature increase observed by subjecting a wax material to differential scanning calorimetry using a differential scanning calorimeter (DSC), it is possible to observe a state change of the wax under heat application and heat absorption peaks accompanying phase transition and melting of the wax.
In accordance with the present invention, there is provided an aesthetically pleasing, pleasant tasting, substantially non-bleeding, striped dentifrice composition comprised of at least two dentifrice components wherein at least one of the components is a paste or gel containing a colorant entrained in a matrix of a synthetic aliphatic hydrocarbon wax particle wherein no waxy off-taste is imparted to the dentifrice, the wax having a melting point range as determined by DSC between about 40° and about 135° C. and the peak endotherm temperature being at least about 65° C.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Synthetic aliphatic hydrocarbon waxes useful in the practice of the present invention include as low-molecular weight polyethylene, low-molecular weight polypropylene, synthetic paraffin wax, oxidation products of aliphatic hydrocarbon waxes, such as oxidized polyethylene wax, and block copolymers thereof. A synthetic wax preferred in the practice of the present invention is a synthetic paraffin wax having a melting point in the range between about 38° and about 110° C. and a peak endotherm temperature, as measured by DSC, in the range of about 90° to about 110° C.
Synthetic aliphatic hydrocarbon waxes are predominately derived from the polymerization of hydrocarbon monomers such as ethylene, propylene and the like and have molecular weights below 10,000. Synthetic aliphatic hydrocarbon waxes include polyethylene waxes and Fisher-Tropsch waxes (polymethylene waxes). Synthetic paraffin wax is synthesized by the Fisher-Tropsch process from carbon monoxide and hydrogen, which are catalytically converted to a mixture of paraffin hydrocarbons; the lower molecular weight fractions are removed by distillation, and the residue is hydrogenated and further treated by percolation through activated charcoal. This mixture may be fractionated into its components by a solvent separation method, using a suitable synthetic isoparaffinic petroleum hydrocarbon solvent. Synthetic paraffin waxes are distinguished from paraffin waxes, which are obtained at different stages in the process of refining crude oil. During such process, the different distillates can be separated by different melting points. Refined paraffin wax is the first fraction to come off the refining processing column. Thereafter microcrystalline wax is distilled off.
The synthetic wax entrained colorant particles are incorporated in the dentifrice component at a concentration of about 0.01 to about 5% by weight and preferably about 0.05 to about 1% by weight.
Colorants suitable for entrainment or encapsulation in the synthetic wax matrix in accordance with the practice of the present invention include physiologically compatible water-soluble dyes and lakes including natural or synthetic dyes of the types permitted in foods and drugs, such as those listed in Title 21 of the U.S. Code of Federal Regulations, Section 74, including for example FD&C Blue #1 and FD&C Yellow #10. In addition to these water-soluble dyes, it is also possible to use water-insoluble dyes, for example Eyeshadow Blue KO, Colour Index 77 510, EG-No., Blue 15 (C-Blue 17), or mixtures of water-insoluble dyes and water-soluble dyes, for example Eyeshadow Blue KO and Lemon Yellow ZN 3, in which case green hues are obtained. Preferred colorants are comprised of 1% to 40% by weight, preferably 10% to 30% by weight, of a water soluble dye on a substrate such as alumina, zirconia and titania and preferably alumina hydrate. Preferred lakes are those certified by the Color Certification Laboratory of the Food and Drug Administration of the Health, Education and Welfare Department of the United States Government, for example, F.D. & C. Blue No. 1 Lake, F.D. & C. Blue No. 2 Lake, F.D. & C. Red No. 3 Lake, F.D. & C. Yellow No. 5 Lake and F.D. & C. Yellow No. 6 Lake.
The colorant may be entrained in the synthetic wax using methods of encapsulation which are known in the art. As these encapsulation methods are not specific parts of the present invention, they will not be described at length herein. Further disclosure of suitable encapsulation methods may be found in Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 125 Pgs. 470-493 (1981) which publication is hereby incorporated by reference.
An example of a method by which colorants such as lakes of the present invention may be entrained in a synthetic wax matrix, such as synthetic paraffin wax, is by mixing about 30-70% by weight of synthetic paraffin wax particles with about 25-35% by weight of an appropriate oil dispersant material to which is added the desired amount of colorant material. The desired amount of colorant material is that amount of colorant which results in a final concentration of up to 20% colorant, preferably 1-10% by weight colorant in the final dried colored synthetic wax particles. A second method of entrainment is by dispersing or dissolving the dye or lake in a synthetic wax that has been thermally softened to form a liquid composition. The dispersion is ag
Benz Claude L.
Miller Jeffrey M.
Prencipe Michael
Wong Michael
Colgate-Palmolive Company
Page Thurman K.
Pulliam Amy E
Shapiro Paul
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