Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2002-05-06
2004-05-11
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C514S844000, C514S846000
Reexamination Certificate
active
06733766
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to personal care products, especially cleansers, which develop color when the compositions are combined with water.
2. The Related Art
Consumers often measure efficacy of a personal care product through some physically perceivable sensorial signal. Skinfeel of a product is one of the most common signals. Silky, non-residue leaving cosmetics are much preferred over tacky ones, and consumers may relate those aesthetics to actual pharmacological performance.
Temperature may operate as a sensorial signal. Coolness can be imparted to toothpastes, aftershave lotions and shower gels through the presence of camphor, menthol or menthol releasing derivatives. Some formulations signal efficacy through a temperature increase. Inclusion of capsaicin gives a brief temperature rise sensation to the human neural system. Exothermic and endothermic reactions are other sources of temperature signaling. U.S. Pat. No. 6,270,783 B1 (Slavtcheff et al.) and WO 01/12150/A1 (Mohammadi) illustrate interactive effects of temperature changes in combination with color generation.
Products by Schering-Plough Healthcare Products, Inc. and related patents introduced a sunscreen lotion with an indicator brightly colorizing the lotion until applied to the human skin. Upon rub-in, the lotion decolorizes or turns clear. A user of the product can through visual means ensure even distribution of the sunscreen over the body. The mechanism is based upon an aqueous system with a pH sensitive indicator. On the skin, water from the lotion evaporates altering pH and eventually decolorizing the applied product. See U.S. Pat. No. 6,086,858 (McEleney et at.), U.S. Pat. No. 6,007,797 (Bell et al.), U.S. Pat. No. 6,146,618 (Bell et al.), U.S. Pat. No. 6,099,825 (McShane et al.), U.S. Pat. No. 6,290,936 B1 (Ross et al.), and U.S. Pat. No. 5,747,011 (Ross et al.).
Use of pH indicators has also been incorporated into a dental floss. See U.S. Pat. No. 5,357,989 (Gathani).
Another commercial embodiment of a color change signal is Biore® Self Heating Mask. The product lists the following ingredients: butylene glycol, sodium silico aluminate, kaolin, PEG-8, methyl gluceth-20, hydroxypropyl cellulose, dimethicone, hydroxypropyl methylcellulose, talc, acrylates copolymer, polyethylene and minor ingredients including encapsulated ultramarine pigments. Instructions on use of the product require wetting of the face which when contacted with the Biore® product causes self-heating by reaction of water with the silico aluminates and kaolin. The composition is applied by rubbing across the face. Massage through the rubbing action breaks the encapsulating material, releasing the ultramarine pigments thereby turning the composition a uniform blue color. Once developed, the blue color signals the consumer it is time to rinse away the product. Further information on this product appears in U.S. Pat. No. 6,309,655 B1 (Minnix). A drawback of this system is the requirement for actual physical breakdown of walls encapsulating the colorant. This procedure is messy and requires an active manipulation. Furthermore, blue beads are visible (ranging from greater than 200 to 800 microns) in the starting Biore® product even before application and wider release of the pigments.
New mechanisms for color change signals have been sought which are less restrictive than those of the known art.
Accordingly, it is an advantage of the present invention to be able to provide personal care products, with a color sensorial signal change.
Another advantage of the present invention is to be able to provide personal care products, especially non-lathering creamy cleansers which change from white to another color after the product is combined with water.
These and other advantages of the present invention will become more readily apparent from consideration of the following summary and detailed discussion.
SUMMARY OF THE INVENTION
A personal care, substantially dry composition is provided which includes:
(i) a colorant activatable in water to reveal a visual color; and
(ii) an oil soluble carrier;
wherein the colorant is insoluble in the carrier and does not impart the visual color to the composition in its substantially dry state.
DETAILED DESCRIPTION
Now it has been found that a color signal can be generated from a substantially dry composition that is an oil soluble carrier formulated with a water soluble inorganic or organic colorant. In the substantially dry state, the composition receives no color contribution from the colorant. However, once a consumer mixes water into the composition, such as in a skin cleansing process, a color change occurs.
The starting color of compositions according to this invention may essentially be any color. However, most preferred is a white or slightly off-white color, usually imparted by an opacifier such as titanium dioxide. Colorants when present as beads may be of a color different from that of the initial color. However, a consumer will essentially not perceive the bead or its color because of its small size. Thus, colorants that may be present in bead form will have an average particle size ranging from about 0.0001 to about 200 &mgr;m, preferably no higher than about 150 &mgr;m, more preferably no higher than about 100 &mgr;m, optimally no higher than about 50 &mgr;m. Advantageously, no more than 30% of the colorant beads should have a particle size greater than 200 &mgr;m, preferably not more than 150 &mgr;m.
Accordingly, an important element of the present invention is that of an oil soluble carrier which is a hydrophobic system of one or more components having a weighted arithmetic mean solubility parameter of less than or equal to 10.5. It is recognized, based on this mathematical definition of solubility parameters, that it is possible, for example, to achieve the required weighted arithmetic mean solubility parameter, i.e. less than or equal to 10.5, for a hydrophobic carrier comprising two or more substances if one of the substances has an individual solubility parameter greater than 10.5.
Solubility parameters are well known to the formulation chemist of ordinary skill in the art and are routinely used as a guide for determining compatibility's and solubilities of materials in the formulation process.
The solubility parameter of a chemical compound, &dgr; is defined as the square root of the cohesive energy density for that compound. Typically, a solubility parameter for a compound is calculated from tabulated values of the additive group contributions for the heat of vaporization and molar volume of the components of that compound, using the following equation:
δ
=
[
∑
i
E
i
∑
i
m
i
]
1
/
2
wherein &Sgr;
i
E
i
=the sum of the heat of vaporization additive group contributions, and &Sgr;
i
m
i
=the sum of the molar volume additive group contributions
Standard tabulations of heat of vaporization and molar volume additive group contributions for a wide variety of atoms and groups of atoms are collected in Barton, A. F. M. Handbook of Solubility Parameters, CRC Press, Chapter 6, Table 3, pp. 64-66 (1985), which is incorporated by reference herein in its entirety. The above solubility parameter equation is described in Fedors, F. R., “A Method for Estimating Both the Solubility Parameters and Molar Volumes of Liquids”, Polymer Engineering and Science, vol. 14, no. 2, pp. 147-154 (February 1974), which is incorporated by reference herein in its entirety.
Solubility parameters obey the law of mixtures such that the solubility parameter for a mixture of materials is given by the weighted arithmetic mean (i.e. the weighted average) of the solubility parameters for each component of that mixture. See, Handbook of Chemistry and Physics, 57
th
edition, CRC Press, p. C-726 (1976-1977), which is incorporated by reference herein in its entirety.
Formulation chemists typically report and use solubility parameters in units of (cat/cm
3
)
1/2
. The tabulated values of additive group contributions fo
Gott Robert Edward
Padlo Ewa Urszula
Slavtcheff Craig Stephen
Dodson Shelley A.
Honig Milton L.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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