1. Field of the Invention
The present invention relates to topical compositions having a reversible photochromic material that responds to light stimulus. More particularly, the present invention relates to compositions having a photochromic pigment that can be applied to the skin and/or hair in a variety of cosmetic, personal care, over-the-counter and pharmaceutical products. The present invention provides a consumer perceptible stimuli to indicate application/duration of product on the consumer, as well as for decorative purposes.
2. Description of the Prior Art
A variety of cosmetic, personal care, consumer and medicinal products, including over-the-counter and pharmaceutical products, could benefit by using visual calorimetric signals responsive to changes in light. For example, there is growing recognition of the fact that over-exposure to the sun""s rays is instrumental in causing aging of the skin and the development of related medical conditions such as skin cancer. A variety of suncare products have been developed to help reduce the risks associated with exposure to the sun. For example, some products use color as an indicator to determine whether the product has been initially applied over the desired skin areas. Some such products go on colored and become invisible as they are rubbed into the skin.
A problem with such suncare products is determining whether product that was earlier applied is still present and providing protection from the sun. Typically, such products are formulated to be water-resistant. However, after exposure to water, and/or excessive perspiration, it is uncertain as to how much suncare product has worn off and how much remains effective on the skin. The present invention provides a solution to this problem and an easy way to determine where sunscreen or other personal care or other outdoor protection product has been removed (i.e., whether previously applied product is still present).
In addition to suncare products, colorimetric signals, particularly photochromic indicators, are useful for a number of commercial products, including but not limited to, oral care products, surfactant/cleaning products, over-the-counter drugs and pharmaceuticals, artificial tanning products, sporting camouflage, foot-care products, liquid and bar soaps, anti-perspirant and deodorant products, fragrance-emitting products, analgesics, insect repellents, poison ivy products including poison ivy blocks, jellyfish protectants, hair care products, shampoos, conditioners, hair colors, hair styling products, hair mascaras, and decorative cosmetics including various make-up products, pressed powder, mascara, eye liners, temporary and permanent tattoos, body art, lipsticks, lip gloss and lip balms.
Compositions containing temporary visual indicators activated by change in pH and methods of use are known in the art. For example, U.S. Pat. No. 5,523,075 to Fuerst, et al. is directed to suncare cosmetic compositions that contain the indicator phenolphthalein which can be seen when a composition is applied to the skin and thereafter becomes colorless in response to a pH change. The pH change is mediated by an ingredient, which alters pH following application to the skin.
U.S. Pat. No. 5,532,029 also to Fuerst, et al. is directed to a paint ball that responds to a change in pH by changing from one color to another, or changing from colorless to a color, or changing from a color to colorless. The paint balls contain a pH-modifying substance that effects the change in color upon contact with an object or person.
U.S. Pat. No. 5,837,645 to Fuerst, et al. is directed to a method for marking a surface with a temporary visual indicator, which involves a pH change mechanism. The method of this patent employs compositions that contain an indicator and a pH modifying substance. The indicator is invisible at an initial pH and becomes a visible color after application at a second pH. The pH modifying substance of the applied composition evaporates or degrades upon application. This effects a change in pH that causes the indicator to change from invisible to a visible color. The color change is not reversible.
U.S. Pat. No. 5,997,891 to Fuerst, et al. is directed to compositions, which change color in response to a pH change. Compositions for use as sunscreens, paints, lacquers, sealants, protectants, polishes, varnishes, herbicides, pesticides, fertilizers, antibacterials, antiseptics, topical dermatologicals, and ophthalmological sprays or lotions. Compositions of this patent have a temporary visual indicator that changes color in response to changes in pH. Changes from one color to another, from colorless to a visible color, and from visible color to colorless, are described.
U.S. Pat. No. 6,139,821 to Fuerst, et al. is directed to sunscreen compositions that contain a temporary visual indicator that changes color when applied to the skin. The visual indicators of the compositions of this patent change color in response to a pH change mediated by a volatile base ingredient. The base evaporates producing a pH change that produces a color change in the indicator.
Both thermochromic and photochromic materials are known in the art. With regard to thermochromic materials, which show reversible color changes in response to changes in temperature, compositions of three components, namely an acidic substance, an acid developing substance, and a solvent, are known. Concerning photochromic materials, conventional inorganic photochromic compounds, such as silver halides, are well known in the art. More recently, a wide variety of organic photochromic compounds, which show reversible color changes in response to changes in light, have been developed. Such organic photochromic compounds generally show more sensitive color changes between colored and colorless states and offer a diverse color selection. Also, these organic compounds are generally more suitable for addition to organic compositions than are conventional inorganic photochromic compounds.
U.S. Pat. No. 4,666,949 to Shimizu et al. is directed to thermochromic polyurethane foam compositions. The thermochromic compositions, which serve as the coloring agent of the polyurethanane foam, have three ingredients, an electron-donating chromogenic material, an acidic substance, and a solvent, which are enclosed in microcapsules.
U.S. Pat. No. 5,221,288 to Kamata et al. is directed to methodology for dyeing cellulose fiber textile products involving use of thermochromic material encapsulated in polymer microcapsules and/or photochromic material encapsulated in polymer microcapsules or in particles of a polymer matrix.
U.S. Pat. No. 5,252,103 to Kamata et al. is directed to methodology for pigmenting or dyeing cellulose fiber textile products. The methodology may utilize photochromic microcapsules or thermochromic microcapsules that provide reversible color changes.
U.S. Pat. No. 6,290,977 to Friars et al. provides flowable personal care compositions having a thermochromic pigment, and a methodology for sensing or recording the temperature of skin using compositions having a thermochromic pigment.
However, in spite of the variety of chemical materials that show color change in response to chemical or physical stimuli, there remains a need, especially in the cosmetic and personal care industries, for products that exhibit colorimetric signals in response to changes in light. More particularly, in view of the limitations and demands in these industries, there remains a need for products that show reversible visible color changes in response to changes in light.
It is an object of the present invention to provide compositions that incorporate visual indicators that respond to changes in environmental stimuli.
It is another object of the present invention to provide compositions having a visible color change in response to change in light intensity and/or wavelength.
It is still another object of the present invention to provide compositions having photochromic pigments that exhibit a reversible visible color change in response to a change in light intensity and/or wavelength and that are useful in cosmetics and personal care products.
It is a further object of the present invention to provide compositions having photochromic pigments that exhibit a reversible visible color change in response to a change in light intensity and wavelength to be useful in medical and pharmaceutical procedures.
These and other objects and advantages of the present invention and equivalents thereof, are achieved by topical compositions having a photochromic pigment that provides a visual color signal and exhibits reversible color change in response to a change in light intensity and wavelength, especially as a result of specific light-induced chemical changes in the chromophores.