Thermochromic flowable topical personal care product

Abstract

A topical flowable personal care product, and more specifically, a shower gel shampoo, body lotion, moisturizing cream, sunscreen, skin toner, or the like, exhibiting a thermochromic color change, preferably at a discrete temperature, preferably at a temperature between about 20° C. (room temperature) and about 37° C. (skin or shower-water temperature). The composition thus changes in response to body heat or the heat of a bath or shower.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a novel topical flowable personal care product, and more specifically, a shower gel, shampoo, body lotion, moisturizing cream, sunscreen, skin toner, or the like, exhibiting a thermochromic color change preferably at a temperature between about 20-25° C. (room temperature) and about 37° C. (skin or shower-water temperature). The composition thus changes in response to body heat or the heat of a bath or shower.

2. Description of the Related Art

There is a great amount of competition in the topical personal care product industry for the attention of the consumer. Flowable products have been formulated with unique colors, textures, and scents. Unique dispensers have been developed. Products have been packaged with distinctive bath sponges or applicator pads. However, the basic personal care product formulations themselves have remained little changed.

It is well known that the modern consumer has an appetite for new experiences. There is thus a need for a novel topical personal care product which engages the imagination of the consumer.

SUMMARY OF THE INVENTION

It has now been discovered that personal care products, such as shower gels, shampoos, body lotions, sunscreens or the like, prepared as formulations of thermochromic pigments and personal care active ingredients in a vehicle, in liquid or flowable form, are storage stable, are safe for topical application, do not have adverse skin coloration effects, and provide a novel visual effect.

The novel visual effect is particularly interesting in that it is part of a multi-sensory effect which is surprising and pleasing to the first time user. At the time the product is applied to the skin, the product simultaneously (1) releases fragrance, (2) provides a silky clean feeling, and (3) changes color, all of which signaling activity. Thus, the product simultaneously provides olfactory, tactile, and visual effects, which reinforce the perception that the product is exciting.

When the concentration of thermochromic pigment is low, the products behave similarly to any shower gel, shampoo, body lotion, or the like, except that, after being applied to the skin or introduced into bath water, the product itself changes in color from a first to a second color, e.g., purple to pink. As the product dissipates in water or is distributed over the skin, the coloration tends to become undetectable.

When higher concentrations of thermochromic pigment are used, the product tends to provide a low level of thermochromic coloration to the skin or hair. The effect is temporary and is washed away as the product is washed off the skin or out of the hair.

For amusement purposes, a high concentration thermochromic product can be used for temporary, easily washed off thermochromic body art. The composition can be applied in patterns forming words, symbols or pictures. One thermochromic formulation may be applied alone, two or more thermochromic compositions may be applied side-by-side, or mixtures of thermochromic materials may be applied to the skin.

In all cases, the product easily washes off of the skin in the same way as any shower gel, shampoo, body lotion, or the like.

The pigments may be reversible thermochromic pigments or non-reversible thermochromic pigments.

The composition is most preferably formulated as a shower gel, a shampoo, or a body lotion which can be easily applied by hand to skin or hair, and can be washed off with little or no scrubbing.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Once appraised of the present invention, a wide variety of specific formulations become apparent to the personal care products technician. Virtually any personal care product can be modified to incorporate thermochromic materials. Thermochromic materials are well known, and any of these can be used in the present invention, so long as formulations containing them meet health and safety requirements.

Central to the present invention is that the product can be easily washed away from hair or skin. The product is not a long-lasting cosmetic such as lipstick or mascara.

The individual ingredients will now be discussed in greater detail.

Reversible Thermochromic Materials

The thermochromic materials used herein may be in the form of fine pigment particles, micro-encapsulated materials, or molecular materials, and among these fine pigment particles are preferred. It should be understood that the term thermochromic material is used herein to mean any and all thermochromic materials inclusive of quasi-reversible and pseudo-thermochromic materials which show a hysteresis of thermochromism. The materials are, however, not thermochromic liquid crystal materials. The materials are preferably in the form of pigment particles.

Suitable thermochromic materials are available from Clark R&D Ltd., 1225 Carnegie St., Suite 102, Rolling Meadows, Ill. 60008 under the trademark ColorTell™. Clark R&D uses pigments supplied by Matsui Shikiso Chemical Co., Ltd. (Kyoto, Japan), and then creates the different forms of inks, i.e., paraffin wax based inks, water dispersion inks, mineral oil dispersion inks, etc. Clark prints these inks onto plastic cups, baby bottles, beverage containers, thermometers, or spoons, so that the printed area may change color, e.g., to say hot or cold. Prior to the present invention, these inks had not been used in topical personal care products. ColorTell™ Printing Inks are available in 12 basic colors and in unlimited colors when combined with non-thermochromic materials. All of the inks are available in 18 different temperature ranges varying from 5° to 338° F. Inks can go from a low temperature color to colorless at a higher temperature, or go from low temperature color to a higher temperature color, or it is possible to have a 3 color change from a first color at a lower temperature, a second color at an intermediate temperature, and a third color at a higher temperature. ColorTell™ inks are low in VOC's as a result of being formulated with water, and they are virtually odor free. All of the inks are non-toxic upon drying and can be applied to almost any type of substrate.

Not until the present invention was the possibility considered of formulating a topical personal care product for application of such materials directly onto the body for changing color with changes in temperature.

Reversible thermochromic compositions are known which are constituted of a solubilized mixture containing essentially a reaction medium for causing reversible electron exchange between an electron-donating coloring organic compound and an electron-accepting organic compound in a specific temperature range as disclosed in U.S. Pat. Nos. 4,028,118; 4,732,810; 4,865,648; 4,720,301; 4,957,949; 4,554,565; 4,421,560; 4,425,161; and 4,421,560.

Additional examples of reversible thermochromic materials that can be used in the present invention include those disclosed in U.S. Pat. No. 5,281,570 (Hasegawa, et al.) entitled “Thermochromic materials” teaching a microencapsulated reversible thermochromic material comprising: (a) an electron donative color former; (b) a sulfide, sulfoxide or sulfone containing a hydroxy phenyl radical; and (c) a chemical compound selected from alcohols, esters, ethers, ketones, carboxylic acids or acid amides; U.S. Pat. No. 4,425,161 (Shibahashi, et al.) entitled “Thermochromic materials” teaching a thermochromic material comprising (a) an electron-donating, chromatic organic compound, (b) a compound capable of reversibly accepting an electron or electrons from the electron-donating, chromatic organic compound, (c) a compound controlling the temperature and sensitivity of coloration/decoloration of the thermochromic material and (d) a N-radical, P-radical, O-radical or S-radical cationic compound having an aromatic ring or rings which improves by light-fastness; U.S. Pat. No. 4,717,710 (Shimizu, et al.) entitled “Thermochromic composition” teaching a thermochromic composition comprising (1) an electron-donating chromogenic material, (2) a 1,2,3-triazole compound, (3) a weakly basic, sparingly soluble azomethine or carboxylic acid primary amine salt, and (4) an alcohol, amide or ester serving as a solvent; and U.S. Pat. No. 5,558,700 (Shibahashi, et al.) entitled “Reversible thermochromic composition” teaching a reversible thermochromic composition comprising a solubilized mixture of three components of (a) an electron-donating color-developing organic compound selected from pyridine types, quinazoline types, and bisquinazoline types of compound, (b) an electron-accepting compound for the electron-donating color-developing organic compound, and (c) a compound serving as a reaction medium for causing reversibly an electron exchange reaction between the components (a) and (b) within a specified temperature range, the composition developing a fluorescent color of yellow, yellowish orange, orange, reddish orange, or red with a high color density and high color brightness, yet gives no residual color under non-color-developing conditions, and has remarkably improved light resistance.

The acid-responsive chromogenic substance in the thermochromic material includes triphenylmethanephthalide compounds, phthalide compounds, phthalan compounds, acyl-leucomethylene blue compounds, fluoran compounds, triphenylmethane compounds, diphenylmethane compounds, spiropyran compounds and so on. Among species of such compounds are 3,6-dimethoxyfluoran, 3,6-dibutoxyfluoran, 3-diethylamino-6,8-dimethylfluoran, 3-chloro-6-phenylaminofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-7,8-benzofluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 3,3′,3″tris(p-dimethylaminophenyl)phthalide, 3,3′-bis(p-dimethylaminophenyl)-phthalide, 3-diethylamino-7-phenylaminofluoran, 3,3-bis(p-diethylaminophenyl)-6-dimethylaminophthalide, 3-(4-diethyl-aminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide, 3-(4-diethylamino-2-methyl)phenyl-3-(1,2-dimethylindol-3-yl)phthalide, 2′-(2-chloroaniline)-6′-dibutylaminospiro-[phthalido-3,9′-xanthene] and so on.

The acidic substance mentioned above includes 1,2,3-benzotriazole compounds, phenol compounds, thiourea compounds, oxo-aromatic carboxylic acids and so on. Among specific examples of such compounds are 5-butylbenzotriazole, bisbenzotriazole-5-methane, phenol, nonylphenol, bisphenol A, bisphenol F, 2,2′-biphenol, &bgr;-naphthol, 1,5-dihydroxynaphthalene, alkyl p-hydroxybenzoates, phenol resin oligomer and so on.

The amount of the acidic substance may be in the range of about 0.1 to 50 parts by weight per part by weight of the acid-responsive chromogenic substance.

Any of the thermochromic materials each containing an acid-responsive chromogenic substance and an acidic substance are preferably diluted with a solvent before use. The use of a solvent renders the material responsive to change in temperature with greater sensitivity and definition. The solvent which can be used for the thermochromic material includes, among others, alcohols, alcohol-acrylonitrile adducts, azomethine compounds, esters and so on. Among specific examples of the solvent are decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, lauryl alcohol-acrylonitrile adduct, myristyl alcohol-acrylonitrile adduct, stearyl alcohol-acrylonitrile adduct, benzylidene-p-toluidine, benzylidene-butylamine, octyl caprate, decyl caprate, myristyl caprylate, decyl laurate, lauryl laurate, myristyl laurate, decyl myristate, lauryl myristate, cetyl myristate, lauryl palmitate, cetyl palmitate, stearyl palmitate, cetyl p-t-butylbenzoate, stearyl 4-methoxybenzoate, dilauryl thiodipropionate, dimyristyl thiodipropionate, stearyl benzoate, benzyl stearate, dibenzyl thiodipropionate, distearyl thiodipropionate, benzyl benzoate, glycerol trilaurate and so on.

The amount of the solvent may be in the range of 0 to 800 parts by weight, preferably 0.1 to 100 parts by weight, per part by weight of the acid-responsive chromogenic substance.

Most thermochromic dyes undergo a color change from a specific color to colorless (i.e. clear). Therefore, background color pigments can be provided in combination with the thermochromic compounds, such that when the thermochromic compounds change to colorless, the conventional or background pigments define the apparent color. For example, if a yellow pigment is mixed into the body lotion in combination with a red thermochromic dye, the visible color will appear to change from orange to yellow as the person steps into a hot shower; what is really happening is that the red thermochromic dye is changing from yellow to colorless.

Also within the contemplation of the invention are the thermochromic compositions of U.S. Pat. No. 5,919,404 (Fujita, et al.) entitled “Reversible thermochromic compositions” including a reversible thermochromic composition that has a reversible metachromatic function, that is, it presents a color-developed state when heated in a color-extinguished state and presents the color-extinguished state when temperature-dropped or cooled in the color-developed state. The composition comprises as essential components (a) an electron-donating color-developing organic compound, (b) at least one electron-accepting compound selected from alkoxyphenol compounds represented by a given formula, and and (c) a compound such as paraffin wax serving as a reaction medium capable of reversibly causing electron-donating/accepting reaction attributable to the components (a) and (b).

Microencapsulation of Thermochromic Materials

In the present invention, the reversibly variable color material can be directly blended with vehicle or can be microencapsulated beforehand. The microencapsulation can be carried out using the reversibly variable color material, a shell-forming polymer and, where necessary, a surfactant, protective colloid, pH control agent, electrolyte, etc., the desired microcapsules can be prepared in water by any of interfacial polymerization, in situ polymerization, coacervation, air suspension, interfacial precipitation and other techniques. By such processes, microcapsules including the reversibly variable color material and measuring about 1 to 50 &mgr;m in diameter can be obtained. It is also possible to provide double- or multiple-walled microcapsules by using one, two or more of the microencapsulation techniques mentioned above. The preferred shell-forming material includes a polyamine and a carbonyl compound for forming a polyurea shell, a polybasic acid chloride and a polyamine for forming a polyamide shell, a polyisocyanate and a polyhydroxy compound for forming a polyurethane shell, a polybasic acid chloride and a polyhydroxy compound for forming a polyester shell, an epoxy compound and a polyamine for forming an epoxy resin shell, a melamine-formaldehyde prepolymer for forming a melamine resin shell and a urea-formaldehyde prepolymer for forming a urea resin shell, as well as ethylcellulose, polystyrene, polyvinyl acetate and so on. The shell of said microcapsules is preferably made of a thermosetting material which is superior in heat resistance.

Vehicle

The above thermochromic materials can be can mixed into any liquid or fluid vehicle such as found in conventional shampoo, shower gel and body lotion ingredients. Suitable body lotions include those disclosed in U.S. Pat. Nos. 5,198,469 (Sakata); 4,305,961 (Tsutsumi et al.); 4,394,447 (Cadmus et al.); and 4,515,700 (Hitzman). Body lotions vary greatly with taste and are well within the skill of those working in the art to formulate. The major consideration of the present invention is that the formulation not be easily removed in response to mere sweating or mere immersion in warm to hot bath-water, but on the other hand be easily removed by scrubbing with warm soapy water.

U.S. Pat. Nos. 6,001,344 (Vila et al.), 5,993,793 (Simon, et al.), 5,955,406 (Dubief, et al.) and 5,911,981 (Dahms, et al.) all teach suitable shower gel compositions.

Shampoo compositions are very well known, and examples of suitable formulations can be found in U.S. Pat. Nos. 6,007,802 (Coffindaffer, et al.), 6,004,544 (Schrader, et al.), 5,997,854 (von Mallek) and 5,990,059 (Finel, et al.).

The vehicle of the formulations according to the present invention can be in the form of a homogeneous phase formulation or in the form of an emulsion including, but not limited to, oil-in-water, water-in-oil and multiple phase emulsions. These emulsions can cover a broad range of consistencies including thin lotions (which can also be suitable for spray or aerosol delivery), creamy lotions, light creams, heavy creams, and the like. Other suitable topical carriers include anhydrous liquid solvents such as oils and alcohols; aqueous-based single phase liquid solvents (e.g. hydro-alcoholic solvent systems); anhydrous solids and semisolids (such as gels and sticks); and aqueous based gel and mousse systems. Examples of vehicle systems useful in the present invention are described in the following four references all of which are incorporated herein by reference in their entirety: “Sun Products Formulary” Cosmetics & Toiletries, vol. 105, pp. 122-139 (December 1990); “Sun Products Formulary”, Cosmetics & Toiletries, vol. 102, pp. 117-136 (March 1997); U.S. Pat. No. 4,960,764 to Figueroa et al., issued Oct. 2, 1990; and U.S. Pat. No. 4,254,105 to Fukuda et al., issued Mar. 3, 1981.

A typical hand and body lotion in accordance with the present invention may, in addition to an oil-in-water emulsion such as peanut oil, sesame oil, safflower oil, jojoba oil, apricot seed oil, almond oil and mixtures thereof and aloe vera gel and an aqueous carrier, further contain isopropyl palmitate, isopropyl myristate, propylene glycol, glycerine, stearic acid, triethanolamine, tocopherol, panthenol, sodium pyrrolidone carboxycic acid, imidazolidinyl urea, 2-ethylhexyl 4-dimenthylaminobenzoate, methylparaben, propylparaben, citric acid, and fragrances.

A typical night moisturizer cream may comprise, besides an oil-in-water emulsion, sorbitol, stearic acid, glyceryl monostearate, propylene glycol, glycerine, cetyl alcohol, triethanolamine, tocopherol, panthenol, sodium pyrrolidone carboxylic acid, imidazolidinyl urea, surfactant, citric acid, propylparaben, methylparaben, and fragrances.

A typical moisturizing lotion may comprise, besides an oil-in-water emulsion, stearic acid, glyceryl monostearate, 2-ethylhexyl 4-dimethylaminobenzoate, sodium pyrrolidone carboxylic acid, tocopherol, panthenol, biotin, dimethicone, triethanolamine, paraffin, cetyl alcohol, sorbitol, citric acid, guaiazulene, methylparaben, and fragrances.

A typical moisturizing cream may comprise, besides an oil-in-water emulsion, isopropyl palmitate, stearic acid, glyceryl monostearate, cetyl alcohol, triethanolamine, 2-ethylhexyl 4-dimethylaminobenzoate, propylene glycol, tocopherol, panthenol, sodium pyrrolidone carboxylic acid, imidazolidinyl urea, citric acid, sorbitol, propylparaben, methylparaben, and fragrances.

A typical akin toner may comprise, besides an oil-in-water emulsion, witch hazel, glycerine, polysorbate 20, diazolidinyl urea, methylparaben, propylparaben, sodium pyrrolidone carboxylic acid, panthenol, niacinimide, and fragrances.

A cleansing milk may comprise, besides an oil-in-water emulsion, glyceryl stearate, polyethylene glycol-100 stearate, glycerin, stearic acid, triethanolamine, tocopherol, panthenol, sodium pyrrolidone carboxylic acid, biotin, imidazolidinyl urea, hyssop extract, cetyl alcohol, allantoin, propylparaben, methylparaben, citric acid.

A typical skin wash may comprise, besides an oil-in-water emulsion, stearyl alcohol, glycerine cetyl esters, cetyl alcohol, propylene glycol monostearate, sodium lauryl sulfate, alphatocopherol, sodium pyrrolidone carboxylic acid, imidazolidinyl urea, propylparaben, methylparaben, and fragrances.

As disclosed in co-pending U.S. patent application Ser. No. 09/378,402, it has now surprisingly been found that by adding an amount of 1,2-pentanediol the water resistance of a (conventional) cosmetic or dermatological formulation comprising at least one cosmetic and/or dermatological active agent in a cosmetically and/or pharmaceutically acceptable carrier for topical application to the skin of humans or animals can be improved. The 1,2-pentanediol preferably represents more than 0.5% by weight, relative to the total weight of the resulting water resistant composition, more preferably more than 3% and most preferably from 3 to 6%.

With reference to sunscreen type body lotions, the vehicles, in total, typically comprise from about 0.1% to about 99.87% by weight of the sunscreen compositions, preferably from about 80% to about 99%, and most preferably from about 85% to about 95%.

Where the dyes are soluble or dispersible in an aqueous medium, the formulation may be aqueous based. Where the dyes are hydrophilic, they may be mixed into a hydrophobic matrix which is then blended into water to produce an oil-in-water type emulsion. The pH of these oil-in-water emulsion compositions is preferably in the range of from about 4.5 to about 9. Additionally, the mean particle size of the dispersed oil phase materials (e.g., sunscreen agent, thermochromic dye, polymer, perfumes, etc.) dispersed in the aqueous phase of these oil-in-water emulsion compositions may be in the range of from about 5 to about 10 microns with greater than about 75% of the particles being less than about 12 microns.

Fragrance

If added, substances used to produce a desired fragrance may be any one or more of those which are commonly used by those skilled in the art of toiletry fragrance chemistry or perfumery, some of which are listed in the following texts: Robert R. Calkin, J. Stephan Jellinek, Perfumery, Practice and Principle, John Wiley and Sons, Inc., New York, 1994; Rudiger Hall, Dieter Klemme, Jurgen Nienhaus, Guide to Fragrance Ingredients, H&R Edition, R. Gross & Co. Publishing, Hamburg, 1985; Julia Muller, The H&R Book of Perfume, H&R Edition, Johnson Publications, Ltd., London, 1984; Fragrance Guide-Feminine Notes, Masculine Notes, H&R Edition, R. Gross & Co. Publishing, Hamburg, 1985 which are incorporated by reference herein.

EXAMPLE 1

Body Wash

The following ingredients were assembled in the following amounts:

Deionized Water 53.780% Ammonium Lauryl Sulfate(28%) 25.000% Ammonium Lauryl Ether Sulfate(30%) 15.400% Cocamide DEA(80%) 2.500% Ethylene Glycol Monostearate 0.600% ColorTell ™ Thermochromic 0.600% Waterbased Slurry Type 22AQ Fast Blue ColorTell ™ Thermochromic 0.400% Waterbased Slurry Type 45AQ Vermillion Kathon CG 0.200% Ammonium Chloride, 25% 1.600% DRAGOCO Fragrance 0.500%

Colortell™ is a trademark of Clark R&D, Rolling Meadows, Ill. Clark R&D uses pigments supplied by Matsui Shikiso Chemical Co., Ltd. (Kyoto, Japan), and then creates the different forms of inks, i.e., paraffin wax based inks, water dispersion inks, mineral oil dispersion inks, etc.

The water was placed in a vessel and heated to 65° C. and held at this temperature. Under agitation, the surfactants, ammonium lauryl sulfate, ammonium lauryl ether sulfate, cocamide DEA, ethylene and glycol monostearate (EGMS) were added. Once the EGMS had dissolved the mixture was removed from heat and mixing was continued. The thermochromic pigments and Kathon were added while the mixture was about 55° C. The product began to appear light pink. The product was cooled to 35° C.-40° C. while mixing and then fragrance and ammonium chloride were added to the solution. As the product cooled it began turning purple and became completely purple at room temperature.

The product was placed in the hands of a test subject. The heat of the test subject s body was sufficient to turn the product from purple to pink. The same reaction occurred when the composition was applied to the subject s hand and the hand was placed in comfortably hot water.

EXAMPLE 2

The same procedure as in Example 1 was repeated, with the same ingredients, except that as thermochromic material a microencapsulated thermochromic material (trademark: Chromicolor Fast Blue S-27, Matsui Sikiso Chemical Co. Ltd.; a blue acid-responsive chromogenic substance, a phenolic acidic substance and an alcoholic solvent all microencapsulated in thermosetting resin) was added last. The composition is allowed to cool to room temperature to form a body lotion which is blue at 25° C. The composition was applied to the skin and became colorless when exposed to hot water above 35° C.

EXAMPLE 3

The same procedure as in Example 1 was repeated, with the same ingredients, except that as thermochromic material a microencapsulated thermochromic material (trademark: Chromicolor Green S-35, Matsui Shikiso Chemical Co., Ltd.; a green acid-responsive chromogenic substance, a phenolic acidic substance and an alcoholic solvent as microencapsulated in thermosetting resin) was added last. The composition was allowed to cool to room temperature to form a body lotion which was green at room temperature (25° C.). The composition was applied to a hand, and became colorless when warmed to 35° C. The composition was easily removed with soap.

EXAMPLE 4

The same procedure as in Example 1 was repeated, with the same ingredients, except that as thermochromic material a microencapsulated thermochromic material (trademark: Chromicolor Yellow S-15, Matsui Shikiso Chemical Co., Ltd.; a yellow acid-responsive chromogenic substance, a phenolic acidic substance and an alcoholic solvent all microencapsulated in thermosetting resin) and magnesium stearate were added last, and the composition allowed to cool to form a body lotion which was yellow at room temperature. The body lotion was applied to a hand, and upon exposure to hot water became colorless when the temperature reaches 35° C. The lotion became yellow again at 25° C. These changes recurred a number of times. The body lotion was easily removed with soap.

EXAMPLE 5

Color Changing Moisturizing Lotion

The following ingredients were assembled in the following amounts:

PHASE I Deionized Water 77.7% Glycerin 2.0% dl-Panthenol 1.0% Ajidew NL-50-Sodium PCA 2.0% Germall ll 0.2% Carbopol 940 0.2% PHASE II Polawax 4.0% Arlatone T 1.5% Vitamin E 0.5% Crodamol SS - Cetyl Esters 2.0% Crodamol PMP - PPG-2 Myristyl Ether 3.5% Propionate Fancol CB - Cocoa Butter 3.0% Triethanolamine 50% soln 0.4% Colortell Thermochromic Water Based 1.0% Slurry Type 22 AQ - fast blue Dow 1401 1.0% TOTAL 100.00

In a mixing vessel, ingredients 1-5 were weighed and mixed accordingly. Then, ingredient 6 was slowly dispersed to make sure the solution was free from lumps. The formulation was heated to 70° C. to produce Phase I. In a separate beaker, ingredients 7-12 were weighed and melted accordingly to make Phase II. Then, Phase II was added to Phase I and mixed. Ingredient 14 was added in and mixed. The batch was homogenized for 2 minutes in a homogenizer. The batch was removed from the homogenizer and allowed to cool using a triple L blade. The batch was neutralized with ingredient 13. Ingredient 15 was added at 35° C. The composition was mixed until homogenous, cooled to room temperature and transferred to container.

As the product cooled it began turning blue and became completely blue at room temperature.

The product was placed in the hands of a test subject. The product performed in the manner of a moisturizing lotion, with the difference that the heat of the test subject s body was sufficient to turn the product from blue to white. The same reaction occurred when the composition was applied to the subject s hand and placed in comfortably warm water.

It is obvious to those working in this art that the above temperatures can be adjusted to appear or disappear at higher or lower temperatures. Alternatively, color changing temperatures and colors can simply be specified when ordering thermochromic materials from the supplier.

As discussed previously, as the concentration of pigments is varied, the visual effect of the thermochromic pigments changes in character.

At high concentrations, the product of the present invention provides a new, non-permanent, visually interesting form of body art. It is economical to produce, safe to use, stable, can be formulated so as not to be effected by sweat or warm bath-water, and can be easily removed at will, such as with soap.

Further, the topical composition can be used where it is desired to visually determine the skin temperature of a subject. Traditionally, measuring the temperature of a person involves a thermometer. Temperature readings taken by a thermometer are very localized and very accurate. Many times there is a need to recognize the temperature of skin, and to instantly visually recognize whether a certain minimum or maximum temperature has been exceeded. A thermometer is not capable of fulfilling this function.

For example, there is a concern that geriatric patients are sometimes bathed in bath-water that is too hot. After the patent is removed from the water, there is no way to tell whether the patient had been subjected to too-hot water, except by burns. Even in a scalded or burned patient, blisters may not become visible for one or more days, at which time it may no longer be possible to determine the precise origin of the burns. There is thus a need for a way to tell immediately whether a bathed patient has been subjected to too-hot water.

Alternatively, it would be useful to be able to instantly tell whether persons working in cold weather have an unsatisfactorily low body temperature. This can be accomplished by applying to the skin a lotion which changes temper.

Athletes train in temperature extremes. Some athletes, desiring to loose weight, will wear many layers of clothes and exercise in hot whether. Since it is difficult to recognize the signs of hyperthermia or heat shock, these athletes are liable to simply pass out and may even suffer brain damage. Athletes would not exercise with a thermometer in their mouth.

When doing research on the protective quality of winter clothes, it is necessary to monitor the temperature of the skin of the subject being tested. This is difficult to do with thermometers.

Some individuals have suffered nerve damage and are not capable of detecting when water is too hot.

For all these reasons, there is a need for a simple, unobtrusive device capable of measuring or recording whether a certain target skin temperature has been exceeded. There is a need to do this with very simple means, which gives a display which can be easily and immediately optically recognized. Since the skin will be subjected to sweat and/or bath or shower water, the device should be resistant to sweat and hot water.

Once the basic premise of the invention is understood, it will be easily seen how the invention can be used for more artistic pursuits, such as body painting. For example, lotions of different colors and different color changing temperatures can be applied to the skin, either side by side or in layers. Stepping into a bathtub or shower will cause a change in skin temperature, and thus a change in pigment color. These effects can be enjoyed, then scrubbed off with soap.

The present invention is concerned with a technique for detecting or recording changes in skin temperature, to ensure that a certain skin temperature is either not exceeded or not dropped below. This is achieved by formulating a thermochromic lotion in which thermochromic materials are selected not by chemical classification, but by functional properties, most important of which is color change temperature. The thermochromic materials, once compounded into a vehicle and applied to skin, must be able to change color in the temperature range being monitored. For example, in the case of a geriatric patient, the material could be applied to the top of a foot and should change at a temperature of approximately 40° C. In the case of a training athlete, the formulation could be applied as face paint as worn by baseball or football players, and should change color at a temperature of 38° C. It is obvious that an athlete is much more likely to wear face-paint than to exercise with a thermometer in his mouth.

For testing cold weather gear, the formulation should be color-changing at a skin temperature of between 16° C. And 24° C. The thermochromic materials may be selected so as to be either reversible, quasi-reversible, or irreversible.

Although the invention is referred to as a thermochromic lotion, which is the most preferred formulation, it is obvious that the composition can also be in the form of a cream, an ointment, a paste, a free-flowing liquid.

Although this invention has been described in its preferred form with a certain degree of particularity with respect to a body lotion, it could equally well take the form of a cream, paste, ointment, lotion, or stick, and it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in the details of structures and composition of the product may be resorted to without departing from the spirit and scope of the invention.

Claims

1. A flowable topical personal care composition comprising:

(a) a thermochromic pigment capable of color change between a first state and a second state at a temperature of between about 20° C. and about 40° C.; and

(b) a personal care active ingredient,

said ingredients (a) and (b) being stably dispersed in a vehicle.

2. A personal care composition as in claim 1, wherein said composition changes color at a temperature of between 25° C. and 37° C.

3. A personal care composition as in claim 1, wherein said composition changes color at a temperature of between 27° C. and 35° C.

4. A personal care composition as in claim 1, wherein said color change from said second state back to said first state occurs at a temperature less than 8° C. different from the temperature at which said composition changes from said first state to said second state.

5. A personal care composition as in claim 1, wherein said color change from said second state back to a first state occurs at a temperature less than 4° C. different from the temperature at which said composition changes from said first state to said second state.

6. A personal care composition as in claim 1, wherein said composition changes from a first color to a second color at a temperature of between 30° C. and 35° C.

7. A personal care composition as in claim 1, wherein said composition changes color from a first color to a second color at a temperature of between 37° C. and 39° C.

8. A personal care composition as in claim 1, wherein said composition changes from non-colored to colored at a temperature of between 35° C. and 40° C.

9. A personal care composition as in claim 1, wherein said composition changes from non-colored to colored at a temperature of between 37° C. and 39° C.

10. A personal care composition as in claim 1, wherein said composition changes from colored to non-colored at a temperature of between 35° C. and 40° C.

11. A personal care composition as in claim 1, wherein said composition changes from colored to non-colored at a temperature of between 37° C. and 39° C.

12. A personal care composition as in claim 1, wherein said composition comprises from 0.5 wt. % to 2 wt. % thermochromic pigment.

13. A personal care composition as in claim 1, wherein said composition comprises from 0.5 wt. % to 2 wt. % thermochromic pigment.

14. A personal care composition as in claim 1, wherein said thermochromic pigment comprises as essential components (a) an electron-donating color-developing organic compound, (b) at least one electron-accepting compound selected from alkoxyphenol compounds represented by a given formula, and (c) a compound serving as a reaction medium capable of reversibly causing electron-donating/accepting reaction attributable to the components (a) and (b).

15. A personal care composition as in claim 14, wherein said thermochromic pigment presents a color-developed state when heated in a color-extinguished state and presents the color-extinguished state when temperature-dropped or cooled in the color-developed state.

16. A personal care composition as in claim 1, wherein said composition is selected from the group consisting of shower gels, shampoos, body lotions, moisturizer creams, sunscreens, and skin toners.

17. A composition according to claim 1, further comprising at least one additive, said additive being a fragrance, solvent, preserving agent, sequestering agent, thickening agent, emollient, foam-modifying agent, acidifying or basifying agent, dye, viscosity-modifying agent, pearlescence agent, moisturizing agent, anti-dandruff agent, anti-seborrhoeic agent, sunscreen, (nano)pigment, non-organomodified volatile or nonvolatile silicone, organomodified volatile or nonvolatile silicone, or conditioning agent.

18. A personal care composition comprising a thermochromic pigment dispersed in vehicle selected from an oil-in-water emulsion, a gel, or a paste, and having the following characteristics:

capable of being easily applied to skin;

capable of changing color in response skin temperature; and

capable of being easily removed from skin by mild mechanical action and water.

19. A method for sensing or recording the temperature of skin, said method comprising:

(a) applying to skin a topical body composition comprising a thermochromic pigment having a known color change temperature dispersed in vehicle selected from a gel, paste, salve, ointment, lotion, or stick, and having the following characteristics: capable of being easily applied to skin; good staying power on skin when immersed in water up to 35° C.; capable of changing color in response to a change in skin temperature; and capable of being easily removed by scrubbing with soap and water;

(b) monitoring the body composition applied in step (a) for changes in skin temperature; and

(c) removing said body composition from said skin by with water and mechanical action.

20. A method as in claim 19, wherein said method includes applying at least a second topical body composition having a color change reaction differing in color and/or temperature from said first topical body composition.