Natural silicone substitutes for silicone fluids in personal care formulations

Abstract

A silicone substitute for use in a personal care formulation comprising a mixture of at least one polymeric ester and at least one non-polymeric ester, wherein the polymeric ester is an esterification reaction product of (i) at least one first dicarboxylic acid, (ii) at least one first monofunctional alcohol or monofunctional carboxylic acid and (iii) glycerin or derivatives thereof; and the non-polymeric ester is an esterification reaction product of (i) at least one second dicarboxylic acid and (ii) at least one second monofunctional alcohol.

Description

Natural silicone substitutes for silicone fluids in personal care formulations Background of the invention Silicone fluids are widely used in formulations for toiletries, cosmetics, and personal care products. The most frequently used are dimethicone, cyclomethicone, and phenyl trimethicone (hereafter, all silicone materials will be collectively referred to as "silicones"). Incorporated into a skin care formulation, silicone fluids provide a number of benefits, such as improved glide, reduced stickiness, emolliency, and other modifications to the formulation's "feel" characteristics, as well as other advantages. Incorporated into hair care formulations, such as conditioners, they can reduce wet combing strength and increase hair shine. Silicone fluids have been considered particularly useful because they tend to provide the aforementioned benefits without contributing to oiliness or greasiness, and they impart what many consider a "dry" skin feel. This attribute is highly desirable in formulations for toiletries, cosmetics, and other personal care products, such as creams, lotions, antiperspirants, shaving creams, and makeup. Additional benefits include silicones being excellent dispersing and spreading agents, generally water-white in color, having little odor, and being resistant to chemical and oxidative attack. These attributes make them especially suitable for personal care applications. However, the use of silicones in a personal care formulation does have some drawbacks. For example, there has been concern about the safety of using silicone fluids on the skin. Given the potential links between silicone and silicone degradation products and the development of autoimmune system deficiencies in women with silicone breast implants and / or individuals with other disorders, these materials have recently come under increased scrutiny by the Food and Drug Administration (FDA). Although definitive links have not been confirmed, many cosmetic formulators have taken steps to reduce or eliminate silicone ingredients from their formulations. The downside of not using silicones is, of course, the loss of skin feel and the benefits of the formulation. Additionally, silicones have also been implicated as potentially harmful to the environment. For example, the Canadian Ministry of Environment has published a document stating that dimethicones are suspected of being environmental toxins and bioaccumulative. Therefore, there is a need in the field to identify alternative fluids that do not use silicone that provide similar benefits to silicone in formulation, but do not carry the real or perceived risks to health and the environment. The industry has dedicated efforts to addressing this need. For example, U.S. Patent Application Publication 2005 / 0260150 describes low-viscosity esters that can be used as substitutes for low-viscosity silicone fluids. U.S. Patent Application Publication 2004 / 0241200 describes combinations of certain synthetic esters with volatile hydrocarbons that are useful for replacing volatile tetramer and pentamer cyclomethicones. U.S. Patent Application Publication 2009 / 0123398 describes combinations of hydrocarbon fluids useful for replacing volatile tetramer and pentamer cyclomethicones.U.S. Patent Application Publication 2011 / 0064685 describes personal care compositions comprising an aqueous dispersion comprising a metallocene-catalyzed polyolefin and an ethylene-acrylic acid copolymer; a cationic polymer; and at least one cosmetically acceptable surfactant, emollient, or cosmetic active, provided that the personal care composition contains less than 0.09 wt% of silicone 15, and is preferably substantially silicone-free. PCT patent application WO 2005 / 097044 discloses a mixture of pentaerythritol fatty acid esters, wherein the pentaerythritol esters are formed as esterification products of C16 and C18 and pentaerythritol, and the mixture of pentaerythritol fatty acid esters is incorporated into a personal care composition as a wax. This document does not disclose any mixtures of polymeric and non-polymeric esters.The United States Patent Application Publication US 2005 / 0288478 discloses polyol polyester polymers prepared by the esterification of a polyfunctional alcohol, a polyfunctional carboxylic acid, and a monofunctional carboxylic acid. Such polyester polymers have been reported to be useful in personal care formulations when high-viscosity polar oils are desired instead of low-viscosity, non-polymeric esters, which are insufficient. As the public becomes more aware of the potential adverse effects on the body and the environment associated with the use of ingredients derived from fossil fuels, the personal care industry has rapidly moved forward in its search for "natural" ingredients for use in virtually all types and forms of cosmetic formulations. The media has fueled this growth by popularizing the idea that the use of ingredients derived from fossil fuels can have potential adverse effects on the body and the environment. The personal care industry has rapidly moved forward in its attempts to identify "natural" ingredients for use in virtually all types and forms of cosmetic products.Especially, although it is used in marketing materials, the term "natural" has not yet been clearly defined in this context; industry and trade organizations are striving to give the term a more concise and consistent meaning. It may be some time before a universally accepted, industry-wide definition of "natural" is offered; however, it is generally recognized that materials derived from renewable and / or sustainable sources, or that do not use fossil fuels, are considered natural. Petrochemicals are derived from fossil fuels and are not considered natural. Any derivative of petrochemicals is not considered natural. Thus, silicones are not classified as natural, since they are petrochemical derivatives. Consequently, there is a technical need for natural silicone substitutes that can be used in place of silicones in personal care formulations and that provide the consumer with the beneficial end-products of silicones. Brief summary of the invention This document describes a silicone substitute for use in a personal care formulation comprising a mixture of at least one polymeric ester and at least one non-polymeric ester. The polymeric ester is an esterification reaction product of (i) at least one first dicarboxylic acid, (ii) at least one first monofunctional alcohol or monofunctional carboxylic acid, and (iii) glycerin or derivatives thereof. The non-polymeric ester is an esterification reaction product of (i) at least one second dicarboxylic acid and (ii) at least one second monofunctional alcohol, wherein the substitute is substantially silicone-free. A personal care formulation that is substantially silicone-free is also described, wherein the formulation comprises a silicone substitute consisting substantially of a mixture of at least one polymeric ester as described above, and a non-polymeric ester as described above. Related methods are also described. Brief description of the various views of the drawings The foregoing summary can be better understood when read in conjunction with the accompanying drawings. To illustrate aspects of the invention, details and embodiments of the invention are shown in the drawings. It should be understood, however, that the invention is not limited to the specific arrangements and instruments shown. In the drawings: Fig. 1 shows the infrared spectrum of an illustrative non-polymeric ester of the invention, deheptyl succinate; Fig. 2 shows the infrared spectrum of an illustrative polymeric ester of the invention, GSC Type 4; Fig. 3 shows the spreading rate of the silicone substitute compared to that of the conventional silicone material in graphical form; Fig. 4 is a table showing the reagent quantities of various sample and comparator sample formulations provided to human test subjects in a panel evaluation of comparative skin feel properties; Fig. 5 is a copy of the survey used by the panel in the evaluation of the sample and comparative sample formulations; Figure 6 (containing Figures 6A to 6E) shows the results of the panel evaluation in graphical form; Figure 7 is a photographic record of the data demonstrating the comparative adhesiveness (stickiness) of the silicone substitute and the conventional formulation containing silicone; Figure 8 shows the results of the pigment milling evaluation; and Fig. 9 shows the results of an evaluation of the shine (luster) of the hair to which the silicone substitutes were applied. Detailed description of the invention The invention described herein covers silicone substitutes for use in personal care formulations (such as, without limitation, shampoos, cleansers, conditioners, cosmetic products, and lotions) that are substantially free of silicone(s) but have substantially equivalent tactile and / or end-use characteristics. Specifically, the applicants have made the remarkable discovery that by blending certain types of natural ester fluids (i.e., non-petrochemical derivatives), certain desirable characteristics normally attributed to silicone-based personal care formulations can be achieved, including, for example, spread rate, skin feel, reduced stickiness, pigment dispersion, and hair shine.By using the silicone substitutes of the invention, personal care formulations, including skin and hair products, can be formulated that contain natural ingredients, are substantially free of silicone, and are perceived by human end users to have identical or similar aesthetic, tactile and / or skin feel properties to conventional silicone-containing formulations. By "substantially silicone-free," it is understood that the personal care formulations are formulated without the inclusion of any starting compound containing silicone groups. For example, the formulations of the invention contain less than 0.09% by weight of silicone 15, and preferably 0.8% by weight or less. The invention includes a natural silicone substitute for use in personal care formulations that is a mixture of at least one polymeric ester and at least one non-polymeric ester. The term "natural," as used herein to describe any acid, alcohol, and / or ester, means that all the atoms contained in the structure(s) of the acid, ester, or alcohol used to prepare the esters are obtained from renewable and / or sustainable sources. "Renewable and sustainable" means that the carbon is not obtained from petrochemical sources. Illustrative non-petrochemical carbon sources may include, but are not limited to, biomass from plant, agricultural, or forestry waste. Particularly useful in the invention are mixtures or combinations of non-polymeric and polymeric esters derived from the esterification of natural acids and alcohols. The term "esterification" is used herein to describe a condensation reaction between a carboxylic acid group and / or a carboxylic acid ester group with a hydroxyl group. An "esterification reaction product" is a product resulting from this reaction. The silicone substitutes included in the invention are a combination of polymeric and non-polymeric esters formed from esterification reactions. Each of the esters present in the silicone substitute fluid is derived from the esterification of at least one dicarboxylic acid. In the practice of the invention, the polymeric ester is a reaction product of the esterification of at least one first dicarboxylic acid, at least one first monofunctional alcohol or monofunctional carboxylic acid, and glycerin and / or a derivative thereof.The polymeric esters of a given silicone substitute may be made from the same first dicarboxylic acid, first monofunctional alcohol or monofunctional carboxylic acid, and glycerin or a glycerin derivative, or may be prepared from a mixture of first dicarboxylic acids, first monofunctional alcohols and / or monofunctional carboxylic acids, and glycerin or glycerin derivatives or any modification of these materials, such that the "polymeric ester" included in the silicone combination / substitute is, in turn, a combination or mixture of several polymeric esters. The non-polymeric ester of the silicone substitute is a reaction product of at least one second dicarboxylic acid and at least one second monofunctional alcohol. Like polymeric esters, the non-polymeric ester in a given silicone substitute may be made from the same second dicarboxylic acid and a second monofunctional alcohol, or it may be prepared from a mixture of second dicarboxylic acids and second monofunctional alcohols, or any modification of these materials, such that the "non-polymeric ester" included in the silicone combination / substitute is, in turn, a combination or mixture of several non-polymeric esters. In the case of both the polymeric and non-polymeric esters, the suitable dicarboxylic acids and / or monofunctional alcohols may independently contain carbon chains of medium or short lengths (although it is not necessary for the polymeric and non-polymeric esters to be prepared from starting materials having the same number of carbon atoms). By "short" chain length, it is understood that the compound contains approximately one to approximately six carbon atoms. By "medium" chain length, it is understood that the compound contains approximately seven to approximately twelve carbon atoms. In some embodiments, the dicarboxylic acids and / or monofunctional alcohols may independently contain chains of approximately 1, approximately 2, approximately 3, approximately 4, approximately 5, approximately 6, approximately 7, approximately 8, approximately 9, approximately 10, approximately 11, approximately 12, approximately 13, approximately 14, or approximately 15 carbon atoms. In other embodiments, the dicarboxylic acids and / or monofunctional alcohols may independently contain chains of approximately 10 to approximately 25 carbon atoms and / or of approximately 1 to approximately 10 carbon atoms.In any embodiment of the invention, one or more of the dicarboxylic acids and / or monofunctional alcohols may independently have carbon chains that are independently linear and / or branched and / or carbon atoms that are independently saturated and / or unsaturated and / or functionalized or non-functionalized. In some embodiments, at least one of the carbon atoms in the chain is saturated and the others are unsaturated. Particularly useful acids and / or alcohols may be those containing linear, saturated chains containing approximately three to ten carbon atoms. Any dicarboxylic acid known or developed in the art may be independently selected for use in esterification reactions, including, without limitation, 1,4-butanedioic acid (succinic acid), 1,5-pentanedioic acid (glutaric acid), 1,6-hexanedioic acid (adipic acid), 9-nonanedioic acid (azelaic acid), and 1,10-decanedioic acid. In some circumstances, sebacic acid may be preferred. Any known or artifice-developed monofunctional dicarboxylic acid may be independently selected for use in the esterification reaction, including, without limitation, hexanoic acid (caproic acid), heptanoic acid, octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), and dodecanoic acid (lauric acid). In some circumstances, caprylic acid and capric acid may be preferred. Glycerin or glycerin derivatives are used in the preparation of the polymer ester. Glycerin derivatives include, but are not limited to, derivatives of the condensation of glycerol with itself from higher glycerol ether derivatives, known as polyglycols. Any monofunctional alcohol known or developed in the art may be used, including, without limitation, 1-hexanol, 1-heptanol, 1-octanol, 2-octanol, and 1-decanol. Under some conditions, 1-heptanol is preferred. In each case, it may be preferable that the acid(s), alcohol(s) and / or polyol(s) (glycerin or its derivatives) are natural as defined above. In the formation of the esters comprising the silicone substitutes included in the invention from natural reagents, one or more dicarboxylic acids are esterified with one or more monofunctional alcohols and / or one or more monofunctional carboxylic acids. The esters can be formed by any esterification technique known in the art. For example, in a first reaction, a non-polymeric ester derived from the esterification of one or more monofunctional alcohols with one or more dicarboxylic acids is prepared. In a second reaction, a polymeric ester derived from one or more dicarboxylic acids, one or more monofunctional carboxylic acids, and glycerol and / or polyglycerol is prepared. To prepare the silicone substitute, non-polymeric and polymeric esters are then combined in an identified ratio so that the substitute imparts to a personal care formulation performance characteristics corresponding to the silicone fluid that the mixture is intended to replace, such as cyclomethicone and / or dimethicone fluids. "Performance characteristics" means the desirable end-products experienced by the consumer and / or the product formulator that silicone fluids impart to personal care formulations, such as spread rate, skin feel and other tactile properties (slide or drag, oily feel, aftershave feel, skin absorption rate, hair luster / shine, lightness vs. heaviness feel), tackiness (adhesiveness), and the ability to disperse pigments. Polymeric and non-polymeric esters may be present in the silicone substitute in any desired ratio, provided the performance characteristics are achieved or maintained. Evaluating a given combination to ensure it demonstrates the appropriate and desired performance characteristics as a silicone substitute (as dictated by the final personal care formulation) is a matter of routine testing, which is within the skill of an ordinary formulator. In some cases, the weight ratio of polymeric ester to non-polymeric ester may be approximately 1 to approximately 1 to approximately 1: to approximately 50 (i.e., ~1:~1 to ~1:~50). In some circumstances, for formulation convenience, it may be desirable to use a specific polymer-to-nonpolymer ratio in the silicone substitute that is adjusted so that the silicone substitute has a specific viscosity. (In this way, a personal care product formulator seeking to substitute a silicone substitute in their formulation for a silicone of a specific viscosity will not need to modify their formulation in other ways, increasing the convenience of the silicone substitute.) In such circumstances, the specific ratio can be determined by measuring the viscosity of the final product (the silicone substitute) and adjusting the ratio as needed to achieve the target viscosity.For example, a silicone substitute may be desired that has a viscosity of approximately 1 to approximately 1000 cSt, approximately 10 to approximately 500 cSt, approximately 20 to approximately 350 cSt, approximately 50 to approximately 200 cSt, and / or approximately 70 to approximately 100 cSt. In some circumstances, to facilitate handling by personal care formulators, it may be desirable to prepare silicone substitutes that have an identified ratio of polymeric to non-polymeric esters that results in viscosities of approximately 10, approximately 20, approximately 50, approximately 100, approximately 200, and / or approximately 350 (in cSt). The invention also includes personal care formulations that are natural and substantially silicone-free. The personal care formulations include the silicone substitute of the invention and at least one other ingredient (that is not a silicone). Any ingredient that can be applied to hair, skin, or nails, including pharmacological agents, may be included. Illustrative ingredients may include, without limitation, a surfactant, flavoring, fragrance, opacifier, colorant, wax, emulsifier, fat, oil, preservative, UV-absorbing compound, detergent, foaming agents, stabilizers, pH modifiers, moisturizers, water, an alcohol, a urea, a cosmetic active, a pigment, a humectant, a skin or hair conditioner, and a solvent.Other ingredients may include acetone, water, alcohol, parabens, mineral oil, vegetable oil, olive oil, paraffin, PEG, polyethylene, polyethylene glycol, polyoxyethylene, oxinol, petrolatum, sodium lauryl sulfate, sodium laureth sulfate, sodium mireth sulfate, sodium oleth sulfate, sodium ceteareth sulfate, DMDM ​​hydantoin, sodium hydroxymethylglycinate, triethanolamine, cocamide diethanolamine, laurimide diethanolamine, linoleamide diethanolamine, oleamide diethanolamine, oxybenzone, essential oils, an emollient, octyl methoxycinnamate, titanium dioxide, and zinc oxide. Personal care formulations can be prepared by any means known in the art, and the methods will necessarily vary depending on the specific type of personal care formulation being prepared (e.g., an antiperspirant formulation for the underarms versus a cleansing formulation for the skin). The personal care formulation itself can take the form of a solid, semi-solid, liquid, gel, aerosolized or aerosolizable material, film, paste, cream, lotion, emulsion, suspension, and / or powder. The silicone substitute may be present in the personal care formulation in any amount; the amount will vary depending on several factors, including the specific type of personal care formulation being prepared. In some circumstances, it may be preferable for the silicone substitute to be present in the personal care formulation in an amount of approximately 1% to approximately 95% by weight, approximately 5% to approximately 80% by weight, approximately 10% to approximately 70% by weight, approximately 15% to approximately 60% by weight, approximately 20% to approximately 50% by weight, or approximately 30% to approximately 40% by weight of the total composition.It may be preferable that the silicone substitute be present in an amount of approximately 1%, approximately 2%, approximately 3%, approximately 4%, approximately 5%, approximately 6%, approximately 7%, approximately 8%, approximately 9% by weight of the total composition. Both the silicone substitutes and the personal care formulations included in the invention, as described herein, exhibit end-use properties similar or identical to those of their conventionally silicone-containing counterparts. In particular, the difference between a spread value of a silicone combination of the invention or a personal care formulation of the invention ("spread value of the invention") and a spread value of a corresponding conventional silicone or a personal care formulation containing conventional silicone ("conventional spread value") is less than approximately 10%, less than approximately 5%, or less than approximately 1% of the total conventional spread value.Additionally, the skin feel properties, stickiness (adhesiveness), and pigment dispersion capabilities of silicone substitutes and those of the conventional silicone-containing counterpart are similar or statistically identical. Example 1: Preparation of a non-polymeric ester illustrative of the invention The reaction product of 1-heptanol and succinic acid ("diheptyl succinate") was prepared. In a five-liter, four-necked flask equipped with a stirrer, heating mantle, nitrogen gas spray tube, steam column, and total condenser, 2813 grams (24.25 gram moles) of n-heptanol were added. Then, 938 grams (7.94 gram moles) of succinic acid were added. Finally, 7.5 grams of ethanolsulfonic acid (70% aqueous solution) were added as a catalyst. The mixture was heated to approximately 150 °C, and a vacuum was slowly introduced. At the end of this stage, the acid number of the material was measured to be 0.90 mg KOG / g. Subsequently, the mixture was cooled to approximately 90 °C, and a sodium carbonate solution was added to neutralize any residual acidity. The ester was then batch distilled and steam distilled. The steam distilled ester was treated with activated carbon and filtered, yielding an essentially odorless and colorless fluid. The analytical properties of the ester are shown below in Table 1. Table 1 Figure 1 shows the infrared spectrum of the non-polymeric ester prepared as described above. Example 2: Preparation of polymeric esters illustrative of the invention Variants of the reaction product of decanedioic acid ("sebacic acid", derived from castor oil 5) 1,2,3-propanetriol ("glycerol", derived from coconut oil) and octanoic acid ("caprylic acid", derived from coconut oil) were prepared. The amounts of reagents for each variant are given in Table 2.1 below. The esterification / polyesterifications were carried out in a four-necked flask equipped with a stirrer, heating mantle, nitrogen gas spray tube, steam column, and total condenser. In each case, the reagents were loaded into the vessel and heated to approximately 215 °C. Next, the pressure was reduced to expel the reaction water, and the acid number was monitored to track the reaction's progress. When the reaction was sufficiently complete (acid number of 5 mg KOH / g or less), the reactor contents were cooled to approximately 180 °C and steam distilled under vacuum for approximately four hours. The steam distillation was then stopped, and the reaction product was cooled and discharged into containers. Table 2.2 shows the resulting properties. Figure 2 shows the infrared spectrum of the illustrative polymer ester GSC Type 4. Table 2.1 Table 2.2 Example 3: Preparation of the silicone substitute illustrative of the invention The esters from Examples 1 and 2 were combined to prepare a total of approximately 1000 grams of test mixture by stirring in a suitably sized glass beaker with a mechanical stirrer until a clear, homogeneous solution was obtained. Six test mixtures (N10, N20, N50, N100, N200, N350) were prepared to have approximate viscosities of 10 cSt, 20 cSt, 50 cSt, 100 cSt, 200 cSt, and 350 cSt, respectively, measured at 25 °C. Table 3.1 shows the properties obtained for the illustrative silicone substitute of the invention. Table 3.1 Example 4: Evaluation of the spreading rate of the silicone substitute An evaluation was conducted of the spread rates of the silicone substitutes included in the invention compared to the spread rate of several dimethicones commonly used in personal care formulations. As understood in the art, the spread rate or spread value is indicative of the formulation's ability to flow onto the skin after application and is considered an important measure for determining the attributes of a final personal care formulation. Six samples of the silicone substitute of the invention (S1-S6) prepared in Example 3 and six comparative samples of dimethicone fluid (CS1-CS6), each of varying viscosity, were evaluated, as shown in the table below: Sample combination ID Comparative samples 51 N10 CS1 Dimethicone 10 cst 52 N20 CS2 Dimeticona 20 cst 53 N50 CS 3 Dimeticona 50 cst 54 N100 CS4 Dimeticona 100 cst 55 N200 CS5 Dimeticona 200 cst 56 N350 CS6 Dimeticona 350 cst Samples S1–S6 (combination IDS N10, N20, N50, N100, N200, N350) were prepared using the method described in Example 3. Each sample S1–S6 and CS1–CS6 was handled as follows: A piece of filter paper was placed on a Petri dish. Using a pipette, 50 µL of the sample was applied to approximately the center of the filter paper. After periods of 1 minute, 3 minutes, and 5 minutes, the circumference of the sample was traced on the paper. The diameter of each of the circles created was measured. Two measurements were taken for each sample at each time interval. The measurements are shown below. As depicted, the measurements are shown in Figure 3, using viscosity. Figure 3 Example 5: Comparison of the skin feel properties between the mixtures of the invention and silicone fluids The samples were prepared as follows, using the reagent quantities shown in the table in Figure 4. Water, in the quantity indicated for phase A, was heated to 78–80 °C. Using a helix, the remaining ingredients of phase A were combined to form a suspension, which was then mixed with the heated water. The combined ingredients of phase B were heated to 80 °C and added to phase A with continuous mixing. The entire mixture was allowed to cool to 60 °C. Phase C was added to each batch, and the entire mixture was cooled to room temperature. Four ounces of each formulation were packaged in a glass jar. Study participants were instructed to apply 0.10–0.20 g of lotion to the inside of their forearm (one formulation per arm). Participants were then asked to complete a survey. The survey is attached hereto in Figure 5. The data generated by the surveys are shown in a graph in Figure 6 (6A–6D). The results of this study indicate that silicone substitutes have a similar performance to dimethicone homologs. Six sample combinations (S1-S6) were created by combining 20 wt% of Lexorex 200 (a proprietary combination of a trimethylpentanediol / adipic acid / glycerin crosspolymer; available from Inolex Chemical Company, Philadelphia, PA, USA) and 80 wt% of each of the S1-S6 samples, as shown below: Lexorex 200 is a viscous polyester with a viscosity of approximately 25,000 cP at 25 °C. Samples S1–S6 were prepared as described in Example 7. Using a disposable transfer pipette, 0.20 g of Lexorex 200 was applied to the left side of a Petri dish, and 0.20 g of each of S1–S6 was applied to the right side. Each sample was then spread manually to cover a circle with a diameter of 2 cm. A standard cotton ball (purchased from a beauty supply store) was placed on top of each sample circle. The cotton ball was pressed into the sample and then removed with an upward motion. The amount of cotton fiber remaining on each sample circle was visually assessed and recorded photographically. The photos created are shown in Figure 7. In each case, the silicone substitutes of the invention exhibit reduced or low stickiness (dry skin sensation), a characteristic associated with silicones. Example 7: Evaluation of pigment milling The ability of silicone substitutes to act as pigment dispersants was evaluated by assessing the viscosity and appearance of pigment milling grades. This ability is significant, given that high-concentration, low-viscosity pigment dispersions are used in color cosmetics. Nine test formulations were prepared by combining the ingredients as shown in the following table: LexFeel 700 is a pentaentrite / heptanoate / caprylate / caprate combination available from Inolex Chemical Company, Philadelphia, PA, USA. Combinations N10, N20, N50, N100, N200, and N350 were prepared as described in Example 3. The dimethicone / silicone substitute selected for the test was gradually mixed with the red lake pigment until the pigment was moistened to avoid losing it in a cloud of dust. Mixing continued until the pigment was completely dispersed. The viscosity of each of the test combinations A through I was measured using a Brookfield viscometer with a TD spindle and helipath stand. The results are shown in Figure 8. The data indicate that the standard silicone substitutes are comparable to the silicone blend and facilitate acceptable pigment dispersion. The silicone substitute blends were easy to mix, and the resulting viscosities were low. Example 8: Brightness Assessment The ability of silicone substitutes to impart shine was evaluated compared to dimethicone homologs, specifically on human hair. Silicones, both dimethicone and cyclomethicone, are commonly used to add shine to hair products, but they often build up in the hair and do not break down in the environment after washing. Test formulations A through L were prepared by mixing the ingredients of each as indicated in the table below: The combinations N10, N20, N50, N100, N200 and N350 were prepared as set out in Example 3. Intact strands of human hair were cut into thirteen 8 cm strips. Each strand was washed with shampoo and rinsed with deionized water for one minute. Each strand was sprayed with one of the test formulations A to L, with one untreated strand included. Each strand was wrapped around a 28 cm cylinder and allowed to air dry. To assess gloss, the cylinder was placed on a flat surface 1 meter away from a current-indicating work light. All other light sources were removed. The cylinder with the strands was illuminated with the current-indicating light. A photograph of the hair was taken, and the gloss bandwidth was measured. The collected data are displayed in a graph in Figure 9. Based on these data, it can be concluded that the silicone substitutes are comparable to dimethicone homologs, as they impart a similar gloss to the hair, leaving a shiny finish. Example 9: Natural moisturizing lotion for the skin: A natural moisturizing skin lotion is prepared using the silicone substitute of the invention. The ingredients used in the formulation are listed in the following table: continuation The ingredients of Phase A are mixed and heated to 80°C. The ingredients of Phase C are premixed together, then added to the heated Phase A mixture using a spiral mixer. The A / C mixture is then heated to 80°C. The ingredients of Phase B are premixed. Once the A / C mixture reaches 80°C, it is added to the Phase B premix using a spiral mixer. Mixing continues until the entire formulation is uniformly blended. The formulation is then cooled to room temperature while mixing continues. Following evaluation, it was determined that the lotion has a pH of 5.82 at 25°C and a Brookfield viscosity of 39,000 cps at 25°C, and that the lotion has both a dry skin feel and a pigment dispersion capacity similar to that of a lotion containing dimethicone. Example 10: Antiperspirant stick An antiperspirant stick formulation is prepared using the substitute of the invention. The ingredients used in the formulation are listed below: The ingredients of phase A are mixed using moderate propeller stirring and heated to 80 °C. Subsequently, each ingredient of phase B is added individually to the phase A mixture while maintaining the temperature. Mixing is carried out with moderate propeller stirring. The final mixture is cooled to room temperature. The resulting antiperspirant product does not contain silicones, but it has the dry skin feel and smooth application properties of formulations containing cyclomethicone. Example 11: Natural lip tint A natural lip tint formulation is prepared using the substitute of the invention. The ingredients used in the formulation are listed below: continuation The ingredients of phase A are combined and heated to a temperature of approximately 80°C to 85°C while being mixed in the helix. The pigments of phase B are ground and then added to phase A. The mixture is blended until it appears visually uniform. The heat is removed, and the ingredients of phase C are added. The final mixture is cooled and packaged. Following evaluation, the formulation was shown to have a pH of 5.25 at 25 °C and a Brookfield viscosity of 82,000 cps. Furthermore, the lip tint formulation was found to provide spreadability and skin feel properties similar to those of formulations containing dimethicone. Example 12: Silicone-free natural hair conditioner A silicone-free, natural hair conditioner is prepared using the substitute of the invention. The ingredients used in the formulation are listed below: To prepare the conditioner, the ingredients of phase A are combined and heated to 75°C using a helical mixer. Separately, the ingredients of phase A are combined and also heated to 75°C using a helical mixer. The heat is then removed, and phase B is added to phase A. Once the mixture has cooled to 35°C, the ingredients of phase C are added. The entire formulation is cooled to room temperature while mixing. Formulation evaluation shows that it has a pH of 3.85 at 25°C and a Brookfield viscosity of 35,000 cps at 25°C. Furthermore, the conditioner provides a feel and shine to the hair comparable to that of silicone-containing formulations.

Claims

1. A silicone substitute for use in a personal care formulation comprising a mixture of at least one polymeric ester and at least one non-polymeric ester, wherein the polymeric ester is an esterification reaction product of (i) at least one first dicarboxylic acid, (ii) at least one first monofunctional alcohol or monofunctional carboxylic acid, and (iii) glycerin or derivatives thereof; and the non-polymeric ester is an esterification reaction product of (i) at least one second dicarboxylic acid and (ii) at least one second monofunctional alcohol.

2. The substitute of claim 1, wherein the substitute is substantially silicone-free.

3. The substitute of claim 1, wherein at least one of the polymeric ester and the non-polymeric ester is natural. 4.The substitute of claim 1, wherein at least one of the first or second monofunctional alcohols is independently selected from monofunctional alcohols having from approximately 1 carbon atom to approximately 25 carbon atoms.

5. The substitute of claim 1, wherein at least one of the first or second monofunctional alcohols is independently selected from monofunctional alcohols having from approximately 1 carbon atom to approximately 10 carbon atoms. 6.The substitute of claim 1, wherein at least one of the first or second monofunctional alcohols is independently selected from a monofunctional alcohol having approximately 1 carbon atom, a monofunctional alcohol having approximately 2 carbon atoms, a monofunctional alcohol having approximately 3 carbon atoms, having approximately 4 carbon atoms, a monofunctional alcohol having approximately 5 carbon atoms, having approximately 6 carbon atoms, a monofunctional alcohol having approximately 7 carbon atoms, a monofunctional alcohol having approximately 8 carbon atoms, a monofunctional alcohol having approximately 9 carbon atoms, a monofunctional alcohol having approximately 10 carbon atoms, a monofunctional alcohol having approximately 11 carbon atoms, and a monofunctional alcohol having approximately 12 carbon atoms. 7.The substitute of claim 1, wherein at least one of the first or second monofunctional alcohols is independently a straight-chain monofunctional alcohol.

8. The substitute of claim 1, wherein at least one of the first or second dicarboxylic acid is independently selected from dicarboxylic acids having from approximately 5 carbon atoms to approximately 10 carbon atoms.

9. The substitute of claim 1, wherein the substitute has a spreading rate that is substantially equivalent to a spreading rate of a homologous silicone fluid.

10. The substitute of claim 1, wherein the substitute has a pigment dispersing capacity that is substantially equivalent to a pigment dispersing capacity of a homologous silicone fluid. 11.A personal care formulation comprising a silicone substitute consisting substantially of a mixture of at least one polymeric ester and at least one non-polymeric ester, wherein the polymeric ester is an esterification reaction product of (i) at least one first dicarboxylic acid, (ii) at least one first monofunctional alcohol or monofunctional carboxylic acid, and (iii) glycerin or derivatives thereof; and the non-polymeric ester is an esterification reaction product of (i) at least one second dicarboxylic acid and (ii) at least one second monofunctional alcohol, and at least one additional personal care ingredient.

12. The personal care formulation of claim 11, wherein at least one of the polymeric ester and the non-polymeric ester is natural. 13.The personal care formulation of claim 11, wherein at least one of the first or second monofunctional alcohols is independently selected from monofunctional alcohols having from approximately 1 carbon atom to approximately 25 carbon atoms.

14. The personal care formulation of claim 11, wherein at least one of the first or second monofunctional alcohols is independently selected from monofunctional alcohols having from approximately 1 carbon atom to approximately 10 carbon atoms. 15.The personal care formulation of claim 11, wherein at least one of the first or second monofunctional alcohols is independently selected from a monofunctional alcohol having approximately 1 carbon atom, a monofunctional alcohol having approximately 2 carbon atoms, a monofunctional alcohol having approximately 3 carbon atoms, having approximately 4 carbon atoms, a monofunctional alcohol having approximately 5 carbon atoms, having approximately 6 carbon atoms, a monofunctional alcohol having approximately 7 carbon atoms, a monofunctional alcohol having approximately 8 carbon atoms, a monofunctional alcohol having approximately 9 carbon atoms, a monofunctional alcohol having approximately 10 carbon atoms, a monofunctional alcohol having approximately 11 carbon atoms, and a monofunctional alcohol having approximately 12 carbon atoms. 16.The personal care formulation of claim 11, wherein at least one of the first or second monofunctional alcohols is independently a straight-chain monofunctional alcohol.

17. The personal care formulation of claim 11, wherein at least one of the first or second monofunctional alcohols contains at least one saturated carbon atom.

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