Natural thickening and stabilizing systems particularly suitable for the production of cosmetic products

Abstract

A thickening system comprising a) at least one pregelatinized starch, b) at least one gum of plant or microbial origin, and c) at least one cellulose derivative, comprising the steps of: a) providing an aqueous solution; b) heating the water to a temperature between 20°C and 80°C, preferably between 20°C and 50°C; c) introducing the at least one pregelatinized starch, the at least one nonionic polysaccharide, and the at least one anionic polysaccharide into the aqueous solution; and d) stirring the medium until the components are dispersed in the water.

Description

[Background technology]

[0001] Cosmetics are formulated products that are produced by mixing, combining, or forming multiple components.For environmental and sustainability reasons, their formulations are now increasingly sought after from natural rather than synthetic components.For this reason, natural polymers in the form of gums and resins, which have long been used as water-soluble binders, film-forming agents, and even thickeners, are experiencing renewed interest.

[0002] Water is generally a very important ingredient in this type of product: it needs to thicken, i.e. increase its viscosity, to make the cosmetic product easier to handle and apply by the end user, but also to give it a texture that is pleasant in terms of feel on the skin, nails or hair.

[0003] The industry initially used a large amount of naturally derived polymers for this thickening and texturing function, but these polymers had several drawbacks, especially with regard to color, odor, purity, consistency of efficacy, and thickening quality.

[0004] For these reasons, they have been replaced by synthetic or semi-synthetic polymers. In this respect, carbomers are known, which are widely used in cosmetics. The Carbopol® series developed by the company Lubrizol is an example. Mention may be made in particular of the product Carbopol® Ultrez 21, a synthetic acrylate copolymer designed to thicken, stabilize and impart suspending properties to a wide variety of cosmetic formulations. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the cosmetics industry now has to face new challenges related to protecting the environment, preserving our fossil resources, carbon footprint, and consumer safety and protection. In view of this, its formulations are being reconsidered and as much as possible reverted to the use of natural solutions for the formulation of its products. Science and technology in this field are continually advancing to offer reliable and efficient technical solutions that allow formulators to efficiently thicken products made with natural ingredients that are very environmentally and consumer friendly. [Means for solving the problem]

[0006] In this respect, the Applicant has succeeded in developing a novel thickening and stabilizing system starting from a ternary mixture of at least one pregelatinized starch, at least one gum of plant or microbial origin, and at least one cellulose derivative. Starting from this combination, the Applicant has succeeded in developing a thickening system that is particularly suitable for cosmetic formulations.

[0007] The thickening system according to the invention is particularly capable of effectively thickening and stabilizing aqueous solutions, and is able to do so in an entirely unexpected synergistic manner between its various components, in that the viscosity obtained in the presence of the mixture is much higher than that observed with each component separately, or with only two of these components in combination.

[0008] Furthermore, the thickening system according to the invention makes it possible to obtain a very high stability of viscosity, without measurable changes in texture or syneresis, over a period of several months. Such a result is particularly advantageous and makes the thickening system easy to use. This makes it possible to achieve the high level of stability required for cosmetic products.

[0009] With regard to the viscosity of the aqueous medium used and in particular the rheological behavior, the thickening system according to the invention does not exhibit the phenomenon of syneresis, i.e. the formation of a gel solution in the aqueous phase and the separation of water, which is usually observed when natural thickeners are used separately. This is not only very interesting from an application point of view, but also completely surprising, since the products obtained only by using the ternary combination, used alone or in pairs, exhibit prohibitive syneresis.

[0010] From a sensory point of view, the thickening systems according to the invention also provide particularly interesting properties, for example very white, opaque products with a creamy texture are obtained, which make them ideal candidates for thickening and stabilizing emulsions such as care or makeup creams. Furthermore, these products are very advantageously not sticky, do not run and appear particularly soft and bright. DETAILED DESCRIPTION OF THE INVENTION

[0011] The first subject of the invention is therefore a) at least one pregelatinized starch; b) at least one rubber of plant or microbial origin; c) and at least one cellulose derivative The thickening system comprises:

[0012] The ternary thickening combination according to the invention comprises at least one pregelatinized starch as a main component. Such starches include in particular pregelatinized α-glucose polymers of plant origin. Pregelatinized starches derived from corn, potato, wheat, rice, pea, oat, lentil, faba bean, broad bean, kidney bean, and chickpea, or combinations thereof, are particularly preferred.

[0013] Preferably, the pregelatinized starch is a waxy starch, i.e. high in amylopectin and low in amylose, and may in particular be waxy corn, potato, or rice starch.

[0014] Pregelatinized starch is generally produced by thermal, chemical, or mechanical techniques that tend to cause simple swelling, partial disruption, or even total dissolution of the starch granules, thereby rendering them water soluble by a "low-temperature" process by dispersion in water at temperatures below 45°C, better still below 35°C, and even better still near room temperature.

[0015] Thus, preferably the pregelatinized starch no longer contains, or no longer substantially contains, fines that exhibit a Maltese cross in polarized light.

[0016] The preferred techniques for obtaining pregelatinized starch are those of heating / drying starch suspensions in aqueous media, in particular atomization, drum heating, or extrusion. Autoclaving or indirect heating on a heat exchanger are also possible heating methods that tend to obtain complex colloidal dispersions of particles in intact, fragmented, and swollen states. Examples of methods for producing such starches can be found in U.S. Pat. No. 3,086,890, U.S. Pat. No. 3,607,394, or French Patent Application Publication No. 2 822 471.

[0017] This pregelatinized starch may be modified before or after the heating / drying treatment described above. The starch may be pregelatinized or unpregelatinized. With regard to modification, this may be one or more physical, physicochemical, chemical or enzymatic modifications. This may in particular be dextrinization, acid or enzymatic hydrolysis, carboxymethylation, hydroxypropylation, hydroxyethalionation, acetylation, octenylsuccinylation, cationization, crosslinking or grafting. Preferably, the pregelatinized starch is selected from modified starches, in particular dextrinized, hydrolyzed, carboxymethylated, hydroxypropylated, acetylated, octenylsuccinylated or cationic pregelatinized starches. More preferentially, the pregelatinized starch is selected from carboxymethylated, hydroxypropylated, acetylated, octenylsuccinylated pregelatinized starches.

[0018] It should be noted, however, that if certain physicochemical or chemical modification treatments used on starch are sufficiently severe, simple swelling, partial splitting, or even total dissolution of the starch particles is likely, thereby making water soluble by a "low temperature" process unnecessary for thermal or mechanical techniques. In particular, as pregelatinized starch for the purposes of the present invention, there can be used a product that has been only dextrinized, hydrolyzed, cationized, hydroxypropylated, or carboxymethylated, and that no longer contains, or no longer substantially contains, starch particles that exhibit Maltese crosses in polarized light.

[0019] Particularly preferred are non-ionic pregelatinized starches, in particular the series sold by the applicant under the brand name Pregeflo®, an example of such a most preferred starch is for example Pregeflo® CH 40.

[0020] Among the gums of plant or microbial origin that may be mentioned are in particular: Gums derived from plant seeds or exudates, such as gum arabic, konjac gum, guar gum, locust bean gum, tragacanth gum, tara gum, cassia gum, karaya gum, psyllium gum, pectin, or derivatives and mixtures thereof; Gums extracted from algae, such as agar, galactomannan, alginate or carrageenan, or derivatives and mixtures thereof; and gums derived from microbial fermentation, such as xanthan, gellan, mannan, scleroglucan, or derivatives and mixtures thereof, preferably xanthan gum. Examples include:

[0021] Preferably, the gums of plant or microbial origin used in the thickening system according to the invention are non-ionic polysaccharides. Fermentation-derived gums are preferred, such as xanthan, gellan, mannan, and scleroglucan, in particular xanthan and scleroglucan, more particularly xanthan. Such xanthan gums generally have a molecular weight between 1,000,000 and 50,000,000 Da. Among possible commercial products, mention may be made of Xanthan Gum FNCS-PC from Jungbunzlauer International AG, Keltrol® CG-T from CP Kelco, and Cosphaderm® X from Cosphatec. 17, KahlWax's product Kahlgum 6673 FEE - Xanthan Gum, Solvay's products Rhodicare® S and Rhodicare® XC, and Vanderbilt Minerals' product Vanzan® NF-C.

[0022] Cellulose derivatives that can be employed include modified celluloses, particularly methyl cellulose, hydroxyalkyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose, with carboxymethyl cellulose and hydroxyethyl cellulose being preferred. Preferred are celluloses, and most preferred are hydroxyethylcelluloses, and mention may be made in particular of the commercial products Natrosol™ 250 HHR PC from Ashland Specialty Chemical, Espesante CH from Chemir, Tylose™ H 15 YG4 from SE Tylose, and Cellosize™ HEC QP 40 from DowDuPont (Dow).

[0023] The relative proportions between the various components of the ternary mixture are not critical, but in order for the thickening system to be as efficient as possible, it is preferred that the pregelatinized starch is the major component of the thickening system as a whole, i.e., is present in more than 50% of the thickening system as a whole.Thus, the thickening system according to the invention preferentially comprises: a) 1 to 12 dry weight parts of at least one pregelatinized starch; b) 0.01 to 2 parts of at least one rubber of plant or microbial origin; c) and 0.01 to 3 parts of at least one cellulose derivative It consists of:

[0024] More preferentially, this: a) 5 to 11 parts by dry weight of at least one pregelatinized starch; b) 0.1 to 1 part of at least one rubber of plant or microbial origin; c) and 0.1 to 2 parts of at least one cellulose derivative It consists of:

[0025] Very preferentially, this is: a) 6 to 10 parts by dry weight of at least one pregelatinized starch; b) 0.2 to 0.8 parts of at least one rubber of plant or microbial origin; c) and 1 to 1.5 parts of at least one cellulose derivative It consists of:

[0026] Another subject of the present invention is a method for producing a stable thickening system, comprising: a) providing an aqueous solution; b) heating the water to a temperature between 20°C and 80°C, preferentially between 20°C and 50°C; c) introducing into said aqueous solution at least one pregelatinized starch, at least one nonionic polysaccharide, and at least one anionic polysaccharide; d) stirring the medium until a dispersion of the components in water is obtained; The method consists of:

[0027] Those skilled in the art will know how to adapt the stirring speed of the medium, especially as a function of the amount of ingredients to be dispersed, but stirring speeds between 1000 and 5000 rpm appear to be generally acceptable.

[0028] Furthermore, it will be clearly understood that the process according to the invention includes all of the features previously described in relation to the ternary system produced by said process.

[0029] This thickening system has been found to be very stable and non-allergenic to the skin. This has the further advantage that the consistency of viscosity and texture can be obtained independently of pH or the presence of electrolytes. In other words, this system is not affected by the pH of the medium and the presence of monovalent, divalent, and trivalent salts. This criterion is all the more important because, in general, products for cosmetic use, and in particular for topical application, are or are often exposed to pH changes (for example, the pH of the skin is slightly acidic and ranges between 4 and 6). Therefore, there are no specific limitations on use with respect to pH or the presence of salts. Having a product would be a huge technical advantage for cosmetic compositions.

[0030] Finally, the last subject of the invention consists of cosmetic compositions comprising a thickened, stable system according to the invention.

[0031] In particular, the thickened and stable system according to the invention makes it possible to easily produce emulsions that are both very stable and very fine, have a modifiable texture, and have a bright, silky and non-greasy feel even when they contain a large amount of dispersed fatty phase, thus making it possible to obtain emulsions that have a good emollient effect on the skin and also a good moisturizing effect on the upper layers of the epidermis.

[0032] The cosmetic composition may in particular be a care product such as a moisturizing, anti-wrinkle, anti-aging, slimming, antichant or stabilizing composition, a body balm or a beauty mask, and may be in the form of a thickened solution, a gel, a milk, a cream, a suspension, an aerosol or a mousse.

[0033] The cosmetic composition may in particular be a makeup product for the eyes, such as a mascara, a liner, or a makeup product for the face, such as a facial powder, a foundation, or a makeup product for the nails, such as a varnish, or a makeup product for the lips, such as a lipstick or lip gloss.

[0034] The cosmetic composition may in particular be a tanning product, such as a protection product or a self-tanning product.

[0035] The cosmetic composition may in particular be a personal hygiene product, such as a soap, a depilatory, or a deodorant.

[0036] The cosmetic product may in particular be a hair care product, such as a shampoo, a coloring, dyeing or permanent waving product, an anti-hair loss lotion, a lacquer or a fixative.

[0037] The cosmetic composition may in particular be a fragrance, an eau de toilette or an eau de parfum.

[0038] The following examples will allow a more complete understanding of the present invention, but are not intended to limit the scope of the invention. [Example]

[0039] Throughout the examples, various formulations were prepared using the following products: Pregeflo CH 40 sold by Roquette Freres Xanthan gum sold by CP Kelco under the name Keltrol® CG-T Hydroxyethyl cellulose (HEC) sold by Ashland Specialty Chemical under the name Natrosol™ 250 HHR PC

[0040] Unless otherwise stated, all formulations were prepared in the following manner: 1) Weigh and mix various thickeners 2) Heat the water to 40°C. 3) Using a turbo mixer, stir at 2000 rpm to gradually disperse the mixture of ingredients. 4) Continue stirring until the emulsion reaches room temperature.

[0041] All viscosities are measured using a Brookfield DV-II+Pro viscometer.

[0042] Example 1 This example demonstrates the synergistic effect between the three components of the system on thickening aqueous solutions. Table 1 below shows the weight percent of each component in water when used alone, as a binary mixture, or as a ternary system. The thickening system according to the present invention advantageously achieves the highest viscosity while at the same time providing the most comfortable texture on the skin.

[0043] [Table 1]

[0044] Example 2 This example illustrates the syneresis effect observed in a control composition that does not contain all three components that make up the thickening system according to the invention. Table 2 below shows the weight percentage in water of each component used in the various combinations that were prepared. In all cases, another component was added, starch M-DF 12 S, a granular starch that is not a pregelatinized starch as defined above, which had no practical effect on the viscosity.

[0045] All systems outside the scope of the present invention were found to exhibit very significant syneresis, which is a deterrent to their use in cosmetic formulations.

[0046] [Table 2]

[0047] Example 3 This example shows the viscosity changes observed in aqueous solutions thickened with various thickening systems according to the present invention after 15 days, depending on whether the solutions are stored at 4, 40, or 50° C. Table 3 notably shows that viscosity is maintained at all of these temperatures, with virtually no effect of storage temperature.

[0048] [Table 3]

[0049] Example 4 This example shows the evolution of various sensory parameters observed in aqueous solutions thickened with various thickening systems according to the invention after 48 hours. Table 4 shows that it is possible to obtain a satisfactory sensory profile with all the formulations tested. In particular, products are consistently obtained that are non-runny with a descriptor of 3 or less, well-extended with an elongation descriptor of 5 or more, usually 7 or more, slightly sticky with a corresponding descriptor of 4 or less, and permeable with a corresponding sensory descriptor of 6 or more. With the exception of one formulation high in hydroxyethylcellulose, very white formulations are generally obtained with a whiteness descriptor of 6 or more.

[0050] The invention therefore makes it possible to obtain products that are pleasing from a sensory point of view.

[0051] [Table 4]

Claims

1. a) 6 to 10 parts by dry weight of acetylated starch free of starch particles that exhibit Maltese crosses in polarized light; b) 0.2 to 0.8 parts by weight of xanthan gum; c) and 1 to 1.5 parts by weight of hydroxyethyl cellulose, A thickening system consisting of:

2. 10. The thickening system of claim 1, wherein the starch is obtained from corn, potato, wheat, rice, pea, oat, lentil, faba bean, broad bean, kidney bean, and chickpea, or a combination thereof.

3. 1. A method for making a stable thickening system comprising: a) providing water; b) heating the water to a temperature between 20°C and 80°C; c) introducing into said water 6 to 10 parts by dry weight of acetylated starch free of starch granules that exhibit Maltese cross in polarized light, 0.2 to 0.8 parts by weight of xanthan gum, and 1 to 1.5 parts by weight of hydroxyethyl cellulose; d) stirring the medium until a dispersion of the components in the water is obtained; A method comprising:

4. A cosmetic composition comprising the stable thickening system of claim 1 or claim 2.

5. 5. The composition according to claim 4, which is a makeup product for the eyes.

6. 5. The composition of claim 4, which is a tanning product.

7. 5. The composition of claim 4, which is a personal hygiene product.

8. 5. The composition of claim 4, which is a hair care product.

9. 5. The composition of claim 4, which is a fragrance.

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