US 2948657 A
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United States Patent SKIN COLORING COMPOSITIONS Nicholas Bernard Siccama, 659 Squaw Brook Road, N.H., Paterson 3, N.J., and William L. Wirbelauer, deceased, late of Wyckolf, N.J., by Donald J. Chapman and Harry E. Hasselmann, executors, both of 70 Pine St., New York 5, N.Y.
No Drawing. Filed Oct. 9, 1957, Ser. No. 689,044
Claims. (Cl. 167-90) This invention is a continuation-impart of co pending application Serial No. 534,388, filed September 14, 1955, now abandoned, in turn a continuation-impart of application Serial No. 459,851, filed October 1, 1954, the latter of which is now abandoned, which relate to several compositions for coloring human skin, and other surfaces of the human body, such :as the hair [and nails, etc., this application being directed to compositions for coloring the human skin to any desired color or tint adapted as a composition in lotion, cream, gel or paste formfor application as a cosmetic to form a colored protective skin tanning and sun screening coating upon the skin. More particularly, the dermal coloring composition comprises a water soluble colorless indigoid ester dissolved in an aqueous carrier, critically adjusted in pH to a slightly alkaline range above 7 /2, preferably not exceeding about 8 /2, the solution being preferably combined with skin penetration, levelling and fixing substances, enhancing the penetration of the composition into the outer layer of the skin and hair.
The composition of this invention imparts an evenly diffused and firmly fixed color developed in situ on the skin by precipitation of a colorless soluble indigoid ester as a colored insoluble pigment, upon exposure to light. The composition prior to use has relatively permanent chemical stability in storage in containers and, upon application to the skin as a cosmetic product, is activated to a colored coating by light exposure.
It is accordingly the primary object of this invention to provide skin coloring compositions comprising substantially colorless vat esters, preferably indigoid esters, soluble and stable in aqueous or aqueous alcoholic solutions which are alkaline, the composition further essentially containing a fixative and, desirably, skin penetrative, dispersing or wetting and levelling agents whereby the colorless ester may evenly penetrate into the top epidermis layer of the skin, the composition being adapted to develop and become fixed on the skin in a desired pigment form, firmly adherent to the skin, upon exposure to light for a short period of time. The composition for converting to desired viscous liquid, gel or paste form may further contain a thickening agent to optimum cosmetic choice consistency and to allow careful application to specific areas to be tinted.
In addition to the superior properties of a substantially THE SKIN COLORING COMPONENT The substantially colorless esters which are useful in the present invention are a specific group within the broad class of reduced vat colors. The broad class of vat dyes in their so-called soluble colorless form are characterized by being water soluble and some are colorless, or substantially so but most are not, and they are all commonly precipitated to colored insoluble pigment form in normal use for dyeing of textiles at high temperatures including treatment with acids, oxidizing mediae and hot soap solutions, treatments which could not be applied to the human skin because of their harmful reaction as strong, heavy chemicals.
The practically colorless ester compounds useful herein are alkali metal, typically sodium, sulfate ester derivatives of 1-4 conjugated di keto radicals preferably contained in an indigoid system. Our ester compounds contain in their ring system the grouping Such grouping is a reduced or enol form of the colored insoluble keto grouping colorless or, if preferred, desirably slightly colored comformed by hydrolysis of the ester and rearrangement by oxidation.
The soluble colorless esters of the indigoid ring system, which are a preferred type, have the structure wherein X is sulfur or imino and AR completes a single or multiple aromatic ring system containing such radicals as benzene and naphthalene, and which may be substituted with lower alkyl, lower alkoxyl, thio alkyl and halogen groups such as chlorine or bromine. While the single sodium sulfate ester is shown on one hydroxyl, both hydroxyls may be esterified with sodium sulfate ester groups.
When the colorless indigoid compound is exposed to light after coating upon the skin and in the presence of a fixative, the ester group hydrolyzes off, the compound rearranges to the keto form, and the color developed keto compound has the following structure:
4; X \H/ ll AR AR where X and AR are the same as defined above.
The soluble vat esters are well known in the dyeing art for textiles and are commercially available under the names Algosols, Indigosols, Calco soluble vats, S'olvats, Dupont, Soluble Vats, Anthrasols, and others. I
The following are a few esters selected to illustrate a range of colors that develop when the ester is converted to pigment (keto) form:
Algosol (or Indigosol) Brown IRRD (PR-421) sodium sulfate ester of bis-2-1-naphthophen indigo Algosol Orange HR (CI-1217) sodium sulfate ester of ethoxy thio indigo CrHrO Algosol Red IRH (CI-1212) sodium sulfate ester of his (-ch1oro-7-methyl) thio indigo Algosol Red Violet IRRN (PR503) sodium sulfate ester of bis(4,7-dimethyl,5-chloro) thlo indigo on, on; Cl-
Cl S 0 CH; CH5
Algosol Blue 04B (CI-1184) sodium sulfate ester of his 5,7-dibromo-indigo I? H Br 0 it I 0 0:0 Br i (l Many other soluble ester compounds may be selected from the similar known compounds of the art and mixtures of compounds may be used for variation of tint and shade to obtain the color desired.
Moreover, the color may be selected to effect a shade corresponding to some unusual purpose. For instance, a standard light brown color might be applied to the legs to simulate the conventional color of sheer stockings to make their absence less noticeable if none are worn.
Color forming compositions may also be selected, if desired, to give a lighter pigment effect to skin that is naturally dark.
pH RANGE It will be understood that the esterifying sodium sulfate group maintains the structure of the color forming compound in its colorless and reduced state and renders the compound water soluble. These compounds must be maintained substantially alkaline at a pH above 7.5 and preferably in the range of 7.5 to about 8.5 because they will hydroyze to colored form in storage in containers at a lower pH.
The essential alkaline condition of the composition is stressed, because any substantial lowering of pH tends to produce some trace hydrolysis of the ester. For instance, at a pH below about 7.2, trace quantities of the ester become hydrolyzed and progressively oxidized with consequent production of hydrolytic products in solution including sulfuric acid ions. These tend to accelerate the hydrolysis so that thereafter, in a relatively short storage period, the colorless ester compound becomes completely hydrolyzed and precipitated from solution to colored insoluble form in storage, rendering the total composition useless for present purposes.
Where the pH of the solution substantially exceeds 8.5 the rate of development of color is substantially retarded beyond a reasonably short period of light exposure such as more than thirty minutes. Accordingly at a pH below 7.5 the composition is unstable in storage and gives an uneven and poorly adherent coating; and at pHs above 8.5 the time of exposure necessary to develop color may be inconveniently extended.
The pH adjustment is essential and is preferably done on the leuco ester dye substance per se, usually adding small quantities of soda ash or other alkaline substance to the leuco ester dye sufiicient to produce the desired pH in solution. It may be again adjusted in the final composition to assure the required stability, available in the alkaline state.
The soluble indigoid ester in its adjusted alkaline state is dissolved in water or in an aqueous water miscible solvent such as a lower alcohol. The final composition for desirable coloring effect should contain from about 0.1 to 5% by weight of the ester homogeneously dissolved therein. Usually more pronounced color tinting eifects are desired than is available in quantities near the lower limit, so that a preferred range of ester is from 0.5 to 3% or more. The most usually desired color effects upon the skin are available in quantities of about 1.5%. However, that color eifect may be obtained by several applications of more dilute color forming compositions. Sometimes for highly colored localized areas in a single application such as for coloring the hands, it is desired to use much higher color concentrations and 3 to 5%, usually about 4%, will be used.
In formulating the composition, the colorless ester may be made up initially in a substantially more highly concentrated solution in alcohol or water as a stock solution for blending with other desirable components such as diluent carriers, skin penetrative substances, levelling agents, etc. which may be present in substantial quantities. Hence, an initial solution of the ester in water or a mixture of water and alcohol may be made in concentration substantially exceeding this range but which will be ultimately diluted by other components added to the composition so that the ester concentration in the final composition as used for coloring will be in the ranges given.
LIGHT EXPOSURE The alkaline aqueous or aqueous alcohol color forming ester solution when combined with a fixative and applied to the skin will develop color on exposure to light. The time period for color development in combination with the fixative is relatively short ranging from a few minutes up to about thirty minutes, more or less, variable with the amass? type of light. Any type of light over a broad wave length band from about 2900 to 8000 a.u., a range encompassing both visible and ultra violet light, and referred to as actinic light, will develop color by the color forming ester on the skin in the preferred pH adjustment of 7.5 to 8.5. The period of color development will be greatly accelerated and the time period thereby reduced to a few minutes when the exposed coated body portion is exposed to light of shortwave lengths such as the ultra violet range of about 2900 to 3600 an. as available from a suntan lamp radiating light in that range. In ordinary visible light range the time of color development is longer such as up to about thirty minutes after application to the skin. In bright sunlight color development is readily obtained in shorter periods such as even less than five minutes of exposure depending on the light intensity.
The pigment deposits in and on top of the outer skin layer by that light exposure and forms a continuous screening film having the property of absorbing light, as usual with pigments, and has inherently a substantial protective effect upon the skin to absorb and filter light, thereby increasing the resistance of the skin to sunburn.
FIXING AGENTS We have further found that it is essential that the composition contain a substance adapted to accelerate color development and to fix or mordant the ultimately precipitated color upon the skin in a firmly adherent manner as a colored coating of substantial permanence. Particularly, it is found that indigoid ester solutions applied to the skin, while they will develop some color after long periods such as several hours of light exposure, as explained above, are readily removable, since the skin naturally contains oily substance which more or less tends to prevent adhesion and skinpenetration, an effect which may be somewhat offset by inclusion of skin penetrative substances in the composition. It is found, however, that a fixing agent tends to act as a coupling agent to secure fixation of the color upon the skin. That fixing agent has the equally important property of reducing the time period of color development under light exposure.
More particularly, we have found that a specific group of fixing agents are outstandingly useful, not only to effect a relatively permanent bonding of the color upon the skin, but which will greatly accelerate the development of color after application and under light exposure. Useful fixing agents herein are water or alcohol soluble urea compounds or amino acids and salts thereof having respectively the general formulae:
ll RNHC-NHR ll 1 t"ooMe NH,
wherein X is a sulfur, oxygen or imino radical and R is hydrogen, lower alkyl, or hydroxy lower alkyl, R is lower alkyl of l-3 carbon atoms and Me is hydrogen, alkali metal, such as sodium or potasisum, and ammonium. The compounds generally are simple ureas such as urea, thio urea, guanidine; lower dialkyl ureas such as dimethyl urea, and dimethyl thio urea; and lower dialkylol ureas, such as dimethylol urea, dimethylol thio urea, diethylol urea and other ureas of similar characteristics, and simple amino acids or salts like glycine or alanine. The ureas or amino acids may all be homogeneously dissolved in the same solution of colorless ester and stably stored under alkaline conditions as explained above.
In compounding the fixative urea or amino acid compound dissolved with the colorless ester in the same solution, the quantity used is about 2 to 12% preferably about 4 to 8% by weight of the final composition.
6 SKIN 'PENETRATIVE, WETTING AND 'LfivELLINd COMPONENTS The human skin normally carries a more or less oily coating which tends to resist wetting and penetration desirable for even coating of the skin. It is preferred to modifiy the composition with penetrative substances which allow even wetting and dispersing of the composition upon the skin surface so that the composition for coloring purposes will be evenly precipitated as infinitesimal finely diffused insoluble deposits on to the layer of the epidermis, that is, upon the outer skin surface. To enhance the absorption by the skin, it is preferred to use substances which are of a hydrophyllic character. That type of penetrative substance allows even coating and color development by the skin and, after even penetration, absorption and fixation of the color, allows ready removal of the carrier by washing, without, at the same time, removing the color which has become relatively permanently fixed upon the skin. For instance, while carriers of other types might be used, and have some benefit because of the emollient character, they are not only difficult to remove by washing, but most important for the purposes of the present composition, such oily, lipophyllic, substances tend to dissolve the coloring components and prevent intimate wetting of the skin surface by the color forming ester necessary for permanent adhesion. Hence, upon washing of oily compositions on the skin, a substantial amount of the coloring substance becomes removed.
Our preferred hydrophyllic skin penetrative substances comprise higher alcohols, usually liquid non-fatty 2-4 carbon atom alcohols, which may have 2-3 hydroxyl groups, all but one of which may be etherified or esterified. These higher alcohols are compounds having substantial water or aqueous lower alcohol solubility. Useful skin penetrative substances are polyhydroxy alcohols and partial esters thereof in which at least one free hydroxyl group is retained, such as glycerine, ethylene glycol, propylene glycol; polyhydroxy alcohol ethers such as diethylene glycol, glycol mono lower (l-4 C atoms) alkyl ethers, such as mono ethyl ether of ethylene glycol, diethylene glycol mono lower alkyl ether such as methyl, ethyl, propyl and butyl ethers of diethylene glycol commercially available as Carbitols; hydroxy lower aliphatic esters such as diethylene glycol mono acetate, hydroxyethyl acetate and butyl lactate. The quantity of skin penetrative substance used is not critical, and it may be omitted from the composition. We prefer to include the skin penetrative substances for the reasons stated and it will normally be used in quantity of from 0.5 to 25 Weight perecent of the final composition.
The composition further desirably includes levelling agents and wetting agents. The wetting agents tend to maintain the solutions clear, and enhance the penetration and ready removal of other carrier components after color development. Typically useful wetting agents are the dioctyl sodium sulfosuccinate commercially available as aerosols. Various levelling agents are useful and the aerosols inherently have some levelling effect. We prefer to use a liquid aqueous alcohol soluble silicone polymer also known in the art as organopolysiloxane, for example DC-555, a low viscosity non-toxic liquid polyphenyl silicone, for levelling and securing most smooth and even distribution of the color forming composition on the skin.
The levelling and wetting agents when used will be in small quantity of about 0.1 to 3 weight percent of the final composition. Such levelling agent and wetting agents give an improved final smooth even coating and will usually be used in conjunction with the penetrative substance defined above in the composition, but the wetting and levelling. as well as the skin penetrative substances may be omitted with less desirable results in perfect evenness of the color developed and in the other desirable properties mentioned. Some of the unevenness resulting from omission of one or more of these components may be considerably reduced by repeated applications of a color forming composition to the skin whereby several coats applied give a stronger as well as more even color. Oftentimes the practice of producing the color by an application consisting of rubbing in several coats, allowing each to have its color developed before applying the next, is a preferred practice, considering that repeated coatings tend to give a deeper and more intense color. For instance, it may be preferred to apply several color developing compositions in a sequence, each of low pigment forming content, thereby to ultimately produce by repeated application of 2 or more the exact intensity and depth of color desired.
As indicated the composition may also be thickened to any desired consistency and conventional organic or inorganic filler or thickening agents such as methyl cellulose, starch, polyvinyl alcohol, polyvinyl pyn'olidone, gum tragacanth, carboxy methyl cellulose, algin, which may also have been of the character of inert filler substances, such as clay, bentonite, magnesium aluminum silicate, and the like, may be applied in quantity to obtain the desired thickening. However, such thickening agents have little if any effect on the penetration and levelling of the color-forming solution into the skin. Particularly such thickening agents are desirably used only to effect a thickening for improved lotion or cream consistency and for more accurate fiow control useful for localized application.
The composition may also contain such additives as are conventionally useful for specialized purposes for which the composition may be used. For example, in general skin coloring or in an after shave lotion the composition may further contain medicaments, per-fuming agents, etc., and the composition may even contain trace quantities of ordinary colors of any approved type to render the product saleably attractive, such colored additives being in quantity insuflicient to have any pigmenting or substantial ultra violet light retarding effect upon the skin. Such additives may conventionally consist of perfumes, menthol, G1l(2,2-dihydroxy,3',5,6,3,5,6 hexachlor diphenylmethane) all added in trace quantities for their known specific effects.
A suitable base formula for the composition is as follows:
Substance: Weight percent Colorless ester 0.1 to Fixative 2 to 12 Water and optional additive Remainder to 100 Alkali to pH 7.5 to 8.5. Optional additives:
Skin penetrant 0.5 to 25 Ethanol or propanol 0. to 90 Levelling agent 0.1 to 3 Wetting agent 0.1 to 0.3 Perfume, antiseptic, thickener, etc Q.S.
In formulating the composition the fixative urea is first dissolved in warm, aqueous ethyl or propyl alcohol, or water if the solvent is to be entirely aqueous, and thereafter the colorless dry ester or mixture of esters of proper alkalinity is added to the alcohol or water solution of the fixative. The solution may be warmed for rapid dissolving as high as 70 C. and is thereafter allowed to cool. The pH thereof carefully rechecked for adjustment with alkali or ammonia to the required range. Thereafter, the various additives when such are used are added in any sequence, preferably adding the skin penetrant substances, levelling agents, wetting agents, perfumes, antiseptics, etc. in that order with continuous stirring for homogeneous solution.
For application to coloration of the skin to produce for example a. tan color. effect, the composition thus prepared O (a is rubbed over the area of the skin for which color is to be imparted. This is preferably done by use of an absorbent applicator such as a sponge, rubbing the composition evenly over the entire skin area to be colored as a single coating. That skin area is then exposed to light for the period of time sufficient to develop the color, depending upon the character of the light as mentioned above. If desired that skin area may again be coated with several superimposed coatings, the same procedure being repeated until the color of desired depth and evenness is obtained.
The final color produced will not wash OE With ordinary substantially neutral light soapy solution, nor with hot, cold or salt water or even usual detergents, cleansing liquids or solvents. However, a substantial portion of the color can be removed by a much stronger abrasive or scouring action applied with a substantially alkaline soap and warm water.
The following are examples of useful compositions in several applications:
SKIN COLORING EXAMPLE I Component: Weight percent Leuco Ester Brown IRRD 1.00 Leuco Ester Blue 0 13 .20 Silicone 555 (Dow) 3.00 Urea 6.00
Carbitol 0.50 Glycerine 0.50 Aerosol OT 0.20 Water 1000 Alcohol 78.60 Ammonia pH 8.
EXAMPLE II IRRD 1.00 Carbitol 2.00 Glycerine 4.00 Thiourea 6.00, Ethyl alcohol 57.00 Water 20.00 Polyvinyl alcohol thickener 10.00 Ammonia pH 8.
EXAMPLE III IRRD 1.00
Carbitol 1.00 Glycerine 1.00 Dimethyl urea 10.00 Butyl lactate 2.00 Water 10.00
Alcohol 75.00 Ammonia pH 8.
EXAMPLE Iv IRRD 1.00 Silicone 555 (D-C) 1.00 Guanidine 6.00 Aerosol OT 0.50
Water 10.00 Aluminum magnesium silicate thickener 10.00 Alcohol 71.50 Ammonia pH 8.
AFTER SHAVING LOTION EXAMPLE V Component: Weight percent Leuco Ester Brown IRRD 0.80 Leuco Ester Blue 0 B 0.16 Silicone 555 0.50
Glycine 4.00 Glycerine 0.50 Water 10.00
Perfume, etc. 1.00
Ammonia pH 8.
9 EXAMPLE VI IRRD 0.50 Silicone S55 (D-C) 0.50 Urea 3.00 Glycerine 1.00 Water 5.00 Bentonite thickener 10.00 Alcohol 80.00 Ammonia pH 8.
EXAMPLE VII IRRD 0.67 Dirnethylol urea 4.00 Glycerine 1.00 Water 45.00 Menthol Perfume} Alcohol 48.33 Ammonia pH 8.
1. A skin coloring lotion comprising an aqueous solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light and a water soluble fixative compound selected from the group consisting of urea, thio-urea, guanidine, a lower alkyl derivative of said urea fixative compound, a hydroxy lower alkyl derivative of said urea fixative compound, a lower amino acid, and a soluble salt of a lower amino acid, said composition having a pH in the range of about 7.5 to 8.5.
2. A skin coloring lotion comprising an aqueous solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light and small quantities of a water soluble fixative compound selected 'fIOl'Il the group consisting of urea, thio-urea, guanidine, a lower alkyl derivative of said urea fixative compound, a hydroxy lower alkyl derivative of said urea fixative compound, a lower amino acid, and a soluble salt of a lower amino acid and an organopolysiloxane leveling agent and a thickener homogeneously distributed in said solution, said solution having a pH range of about 7.5 to 8.5.
3. A skin coloring lotion comprising an aqueous solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light comprising an aqueous solution of a colorless indigoid ester, a water soluble fixative compound selected from the group consisting of urea, thio-urea, guanidine, a lower alkyl derivative of said urea fixative compound, a hydroxy lower alkyl derivative of said urea fixative compound, a lower amino acid, and a soluble salt of a lower amino acid, and a hydrophyllic skin penetrative substance, said solution having a pH in the range of about 7.5 to 8.5
4. A skin coloring lotion comprising an aqueous solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light and small quantities of a water soluble fixative compound selected from the group consisting of urea, thiourea, guanidine, a lower alkyl derivative of said urea fixative compound, a hydroxy lower alkyl derivative of said urea fixative compound, a lower amino acid, and a soluble salt of a lower amino acid, a leveling agent, a thickener and a wetting agent, said solution having a pH. range of about 7.5 to 8.5.
5. A skin coloring lotion comprising 0.1-5% of a substantially colorless water soluble leuco indigoid ester, about 2 to 10% of a water soluble urea fixative selected from the group consisting of urea, thiourea, guanidine, lower alkyl derivatives of said urea fixative compounds, hydroxy lower alkyl derivatives of said urea fixative compounds, and lower amino acids about 0.5 to 25% of a hydrophyllic skin penetrative substance selected from the group consisting of polyhydroxy alcohols having 2 to 4 carbon atoms and 2 to 3 hydroxyl groups, lower carboxylic acid esters of said polyhydroxy alcohols having at least one free hydroxyl group, lower alkyl ethers of said polyhydroxy alcohols having at least one free hydroxyl group, hydroxy lower alkylene ethers of said polyhydroxy alcohols, and a lower alkyl ester of lactic acid, and the remainder to comprising water, all proportions being by weight, said composition having a pH of from about 7.5 to 8.5.
6. A skin coloring lotion as defined in claim 5 wherein the composition contains up to 3% of organopolysiloxane and suflicient thickener to substantially raise the viscosity of the composition.
7. A skin coloring lotion as defined in claim 1 wherein the aqueous carrier solvent is a dilute aqueous lower 23 carbon mono hydric alcohol solution.
8. A skin coloring lotion as defined in claim 5 wherein the aqueous carrier solvent is a dilute aqueous lower 2-3 carbon mono hydric alcohol solution.
9. A skin coloring lotion comprising an aqueous a1- coholic solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light, and a soluble amino acid fixative substance to accelerate color development upon light exposure and to afiix the developed color upon the skin surface, said solution having a pH range of about 7.5 to 8.5.
10. A skin coloring lotion comprising an aqueous solution of a substantially colorless leuco indigoid ester compound developing color upon exposure to actinic light and a water soluble fixative compound selected from the group consisting of urea, thio-urea, guanidine, a lower alkyl derivative of said urea fixative compound, a hydroxy lower alkyl derivative of said urea fixative compound, a lower amino acid, and an organopolysiloxane leveling agent for said colorless indigoid ester, said lotion being thickened with magnesium aluminum silicate and adjusted to a pH range of about 7.5 to 8.5.
References Cited in the file of this patent UNITED STATES PATENTS 1,918,158 Weisberg July 11, 1933 2,695,259 Carle Nov. 23, 1954 FOREIGN PATENTS 671,122 Great Britain Apr. 30, 1952 949,467 France Feb. 21, 1949 OTHER REFERENCES Vat Dyes, The Application of, A.A.T.C.C. Monograph No. 2, Am. Asso. of Textile Chemists and Colorists, 1953, pp. 94, 95, 256-301.
Plein: J. Amer. Pharm. Asso., Sci. ed., 42:2, February 1953, pp. 79-85.
McGregor: Silicones and Their Uses, McGraw-Hill Book Co., N.Y., 1954, pp. 42 and 89.
Chemical Week, July 17, 1954, p. 52.