Use of an aliphatic ester of a polyglycerol phosphate as an emulsifier for the preparation of compositions for trichological use

Abstract

This patent application relates to the use of an aliphatic ester of a polyglycerol phosphate as an emulsifier for the preparation of compositions for trichological use, wherein the polyglycerol has a number of monomeric units comprised between 4 and 20; the phosphate ester is a polyglycerol monoester; the aliphatic ester is an polyglycerol ester with one or more fatty acid molecules selected from the group consisting of saturated, monounsaturated and polyunsaturated fatty acids with a number of carbon atoms comprised between 4 and 22 or their ester derivatives.

Claims

1. Use of an aliphatic ester of a polyglycerol phosphate as an emulsifier for the preparation of compositions for trichological use, wherein, the polyglycerol has a number of monomeric units ranging between 4 and 20; the phosphate ester is a polyglycerol monoester; the aliphatic ester is a polyglycerol ester with one or more fatty acids molecules, selected from the group consisting of saturated, mono-unsaturated and polyunsaturated fatty acids having a number of carbon atoms comprised between 4 and 22, or their ester derivatives.

2. Use according to claim 1 wherein the polyglycerol has a number of oligomeric units ranging between 4 and 10.

3. Use according to claim 1 wherein the fatty acids of the aliphatic ester are monocarboxylic fatty acids.

4. Use according to claim 1, wherein the fatty acids of the aliphatic ester are selected from the group consisting of: butyric acid (C4:0), caprylic acid (C8:0), capric acid (C10:0), lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), arachic acid (C20:0); palmitoleic acid (C16:1), oleic acid (C18:1); elaidinic acid (or trans-oleic acid) (C18:1); linoleic acid (C18:2), alpha linoleic acid (C18:3), arachic acid (C20:4), eicosapentaenoic acid (or EPA) (C20:5); docosahexaenoic acid (DHA) (C22:6) and combinations thereof.

5. Use according to claim 1, wherein the fatty acids ester derivatives are chosen from alditol or sucrose esters.

6. Use according to claim 1, wherein the aliphatic ester of the polyglycerol phosphate is used for the preparation of compositions for trichological use in combination with additional emulsifying agents selected from one or more of the following: fatty alcohols having a number of carbon atoms comprised between 12 and 22 or their esters with fatty acids; anionic emulsifiers; glycerides of fatty acids.

7. Use according to claim 6, wherein the aliphatic ester of the polyglycerol phosphate constitutes from 30% to 50% of the total emulsifying agents used in the preparation of a composition for trichological use.

8. Use according to claim 1, wherein the aliphatic ester of the polyglycerol phosphate is used in concentration comprised between 3% and 40% by weight of the total weight of a composition for trichological use (w/w).

9. Use according to claim 1, wherein the trichological product compositions for trichological use are selected from the group consisting of: hair dyes, hair care and wellness products, hair conditioners and hairdressing products.

Description

DESCRIPTION OF FIGURES

[0041] FIG. 1: Schematic representation of the process for the synthesis of the aliphatic ester of polyglycerol phosphate used in accordance with the present invention. Esterification: chemical reaction leading to the formation of an ester through the reaction of a fatty acid with an alcohol (in the present case polyglycerol) and the removal of water. Phosphorylation. Chemical reaction between phosphoric acid (or derivatives) and a compound, usually organic, with elimination of one molecule of water (for each radical of the acid introduced).

[0042] FIG. 2: Schematic representation of polyglycerol.

[0043] FIG. 3: Example of a fatty acid in its two isomeric forms cis and trans.

[0044] FIG. 4: Photographic images of the hair to be treated with evident presence of white hair.

[0045] FIG. 5: Photographic images of the hair treated with the dye.

[0046] FIG. 6: Photographic images of the final result.

DETAILED DESCRIPTION OF THE INVENTION

[0047] For the purposes of the present invention, trichological composition (or trichological product) means a composition suitable for application to the hair or skin, intended for the hair or scalp care, hygiene and health.

[0048] Emulsifier means the set of ingredients necessary for the formation of a stable emulsion, formed for example by mixing the functional and accessory ingredients of a finished trichological product.

[0049] The aliphatic ester of polyglycerol phosphate used for the purposes of the invention is described as follows: [0050] polyglycerol has a number of oligomeric units comprised between 4 and 20; [0051] the phosphate ester is a polyglycerol monoester; [0052] aliphatic ester is a polyglycerol ester with one or more fatty acid molecules of plant origin selected from the group consisting of saturated, monounsaturated and polyunsaturated fatty acids with carbon numbers comprised between 4 and 22 or their ester derivatives.

[0053] It should be noted that the polyglycerol phosphate aliphatic ester may be obtained by an esterification and phosphorylation reaction employing techniques known to the skilled person in the art and following the steps shown in FIG. 1.

[0054] Preferably, the polyglycerol phosphate aliphatic ester used for the purposes of the present invention is obtained by a process comprising the following steps: [0055] Esterification between polyglycerol and fatty acid or trans-esterification between polyglycerol and triglyceride (vegetable oil). [0056] Ester or trans-ester phosphorylation.

[0057] It should be noted that polyglycerol refers to an intermolecular glycerol ether formed by the condensation of 2 or more (n) glycerol molecules, with the elimination of a number (n-1) of water molecules (FIG. 2).

[0058] Known since the beginning of the century, polyglycerol esters began to be used in Europe and America in the 1940s. They were introduced to the Japanese market in the early 1960s and some of them were approved in the food sector as from 1981.

[0059] Polyglycerols can be synthesised in various ways by methods involving the condensation of glycerol by alkaline catalysis and the removal of water. The result of this synthesis is normally a mixture of oligomers, including unreacted glycerol, cyclic products and very high oligomers such as decaglycerol.

[0060] The polyglycerol used for the purposes of the present invention is thus a mixture of oligomers having a number of units varying between 4 and 20, preferably between 4 and 10, preferably between 4 and 6. It should be noted that in mixtures containing oligomers having a number of units greater than 4, traces of glycerol and polyglycerols having a number of oligomers less than 4 are still present.

[0061] A brief outline of polyglycerol chemistry can be given by looking at the following table where the linear oligomers of glycerol are described.

[0062] In polyglycerols, the number of OH groups corresponds to the degree of oligomerisation plus 2; therefore, diglycerol (n=2) has 4 OH groups and triglycerol (n=3) 5 OH groups etc. Of the two OH (primary and secondary) groups, it is the number of secondary OH groups that indicates the degree of oligomerisation.

TABLE-US-00001 (n) OH groups Primary Secondary Glycerol 1 3 2 1 Diglycerol 2 4 2 2 Triglycerol 3 5 2 3 Tetraglycerol 4 6 2 4

[0063] It should be noted that, approximately, the molecular weight of the glycerol oligomers is between 166 g/mol (Linear Diglycerol) and 758 g/mol (Linear Decaglycerol).

[0064] According to a preferred embodiment, the polyglycerol phosphate esters are mixed mono- or polyester esters of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids.

[0065] It should be noted that, according to a preferred form of embodiment, mixed polyglycerol polyesters may be obtained using mixtures of fatty acids (saturated, monounsaturated and/or polyunsaturated), for example in the form of vegetable oils.

[0066] Vegetable oils which may be used for the purposes of the invention include, for example, vegetable oils from coconut, palm, babassu, olive, soybean.

[0067] According to an alternative embodiment, polyglycerol esters are pure esters of saturated fatty acids or pure esters of monounsaturated fatty acids or pure esters of polyunsaturated fatty acids. A pure ester is defined as an ester in which the fatty acid esterifying one or more alcohol groups is of one kind only.

[0068] The polyglycerol usable for the purposes of the present invention may be a polyglycerol of plant or synthetic origin; by way of illustration, suitable polyglycerols for the purposes of the present invention are those marketed by Spiga Nord S.p.A.

[0069] Polyglycerol of vegetable origin means polyglycerol obtained by polycondensation of refined glycerins of vegetable origin chosen from at least one of the following: Vegetable origin glycerins, non-GMO (Genetically Modified Organisms) glycerins, Kosher glycerins (where Kosher means the certification issued for consumer products, indicating that the raw materials contained therein comply with the set of religious rules governing the nutrition of observant Jews) and Halal glycerins (where Halal means the certification issued for consumer products, indicating that the raw materials contained therein comply with the precepts of the Islamic Creed and Sharia′a; Halal products do not contain, for example, derivatives of animal origin or ethyl alcohol).

[0070] Plant origin means a compound obtained directly from a plant source or a synthetic compound with a chemical structure that imitates the molecules naturally present in the reference plant species.

[0071] It should be noted that polyglycerol can be esterified either with fatty acids of vegetable origin or with fatty acids of synthetic origin.

[0072] Such fatty acids are, preferably, aliphatic monocarboxylic fatty acids, which can also be used in isomer form.

[0073] According to a preferred embodiment, the saturated fatty acids have a number of carbon atoms comprised between 4 and 22.

[0074] Preferably, the saturated fatty acids suitable for the purposes of the invention are chosen from the group consisting of: butyric acid (C4:0), caprylic acid (C8:0), capric acid (C10:0), lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0) and arachic acid (C20:0).

[0075] According to a preferred embodiment, the monounsaturated fatty acids have a number of carbon atoms comprised between 16 and 18.

[0076] Preferably, the monounsaturated fatty acids suitable for the purposes of the invention are chosen from the group consisting of: palmitoleic acid (C16:1), oleic acid (C18:1) and elaidinic acid (or trans-oleic acid) (C18:1).

[0077] According to a preferred embodiment, the polyunsaturated fatty acids have a number of carbon atoms comprised between 18 and 22 and a number of unsaturations comprised between 2 and 6.

[0078] Preferably, the polyunsaturated fatty acids suitable for the purposes of the invention are chosen from the group consisting of: linoleic acid (C18:2), alpha linoleic acid

[0079] (C18:3), arachic acid (C20:4), eicosapentaenoic acid (or EPA) (C20:5) and docosahexanoic acid (DHA) (C22:6).

[0080] According to a preferred form of implementation, the fatty acids are mixtures of the saturated, unsaturated and polyunsaturated fatty acids described above.

[0081] According to a preferred form of implementation, fatty acids suitable for esterification or trans-esterification of polyglycerol are chosen from one or more of the following:

TABLE-US-00002 Butyric C4:0 Caprylic C8:0 Capric C10:0 Lauric C12:0 Myristic C14:0 Palmitic C16:0 Stearic C18:0 Arachic C20:0 Palmitoleic C16:1 n-7 Oleic C18:1 n-9 (cis) Elaidinic C18:1 n-9 (trans)
or from their homologous (cis) isomers which, having a more linear chain, advantageously have a lower melting point (FIG. 3).

[0082] Preferably, the phosphate ester between polyglycerol and stearic acid gave the best results for the purposes of the present invention.

[0083] According to an alternative embodiment, aliphatic polyglycerol esters may be formed from ester derivatives of the above-mentioned plant-derived fatty acids. Preferably, such ester derivatives are chosen from fatty acid esters with alditols and fatty acid esters with sugars.

[0084] Such fatty acid esters with alditols (alditol esters) or with sugars (sucresters) may be mono-, di- or tri-esters, preferably mono-esters.

[0085] Preferably, sugars suitable for the purposes of the invention are sucrose, glucose, fructose, lactose and maltose.

[0086] Preferably, alditols suitable for the purposes of the invention are sorbitol, mannitol and maltitol.

[0087] In the case of alditols with which fatty acids can be esterified prior to esterification with polyglycerol and subsequent phosphorylation, ester derivatives of fatty acids with sorbitol (sorbitan esters) have proved to be the most suitable for use.

[0088] According to an alternative embodiment, the aliphatic ester of polyglycerol phosphate is used in combination with other emulsifying agents to produce a stable emulsion useful in the preparation of a product for trichological use of interest.

[0089] Preferably, such further emulsifying agents are chosen from one or more of the following: [0090] fatty alcohols having a number of carbon atoms comprised between 12 and 22 or their esters with fatty acids (e.g. cetyl stearate, cetyl palmitate) [0091] anionic emulsifiers (e.g. sulphated alkyl ethers) [0092] fatty acid glycerides (e.g. glyceryl stearates, glyceryl oleates).

[0093] It should be noted that, preferably, the aliphatic ester of polyglycerol phosphate has an HLB (Hydrophilic-lipophilic balance) value ranging between 5 and 12.

[0094] The polyglycerol phosphate aliphatic ester, when used in a mixture with other emulsifying agents, preferably constitutes 20-50% by weight of the total weight of the emulsifying agents used, preferably 30-50% by weight.

[0095] Polyglycerol phosphate aliphatic ester may be used as an emulsifier for the preparation of products for trichological use (semi-finished or finished products) in combination with active ingredients, excipients and/or diluents.

[0096] It should be noted that the active ingredients, excipients and diluents compatible with the aliphatic polyglycerol phosphate ester in the scope of the invention can be chosen from those known to the technician in the field, suitable for application to the hair and scalp, in order to customize and specialize the trichological product from a functional, technological or aesthetic point of view.

[0097] According to a preferred embodiment, the trichological product comprises polyglycerol phosphate ester, or a mixture thereof with other emulsifying excipients, in an amount between 3% and 40% by weight of the total weight of the trichological product (w/w), preferably between 5% and 40% (w/w), preferably between 10% and 40% (w/w), preferably between 10% and 35% (w/w).

[0098] Preferably, the trichological product, prepared using the polyglycerol phosphate aliphatic ester, is chosen from the group consisting of hair dyes, hair care and wellness products, hair conditioning and hair finishing products.

[0099] It should be noted that, in the case of hair dyes, the concentration of the polyglycerol phosphate ester varies between 5% and 10% by weight of the total weight of the dye.

[0100] Hair care and wellness products means masks, conditioners and creams applied to the hair or scalp to obtain a cosmetic, perfecting, volumising, polishing and restructuring effect; hair conditioning and finishing products are products to facilitate hair styling, holding and setting.

[0101] Examples of hair care and beauty products are masks for conditioning the hair, reconstructing and finishing the hair, masks with sebum-regulating and astringent functions, smoothing, curling, anti-frizz functions, etc.

[0102] Preferably, the trichological product is a hair dye.

[0103] For the purposes of the invention, a hair dye is understood to be a permanent hair dye, a temporary hair dye or a semi-permanent hair dye; according to a preferred form, decolorizers and oxidizers are also included in the definition of hair dye.

[0104] Preferably, the trichological product is a permanent hair dye.

EXAMPLES

[0105] For illustrative purposes and without limitation, the following are examples of products for trichological use according to the present invention.

[0106] During colouring and decolouring treatments, the percentage of keratin present in the hair decreases, disulfide bridges and cysteine filaments break down. In order to restore brittle and damaged hair to its optimal condition, a shock treatment (reconstruction) and a maintenance treatment (mask, conditioner) are frequently used to preserve the normal structure of the hair after washing or as an “additive” during colouring, decolouring or other processes.

TABLE-US-00003 Hair conditioning mask Function Ingredient Concentration Emulsifier Polyglycerol/fatty acid 3-5% composition phosphate Cetylstearyl alcohol 2-4% Glycerylmonostearate 1-2% Secondary Propanediol (vegetable) 3-5% solvent Surfactant Non-ionic, amphoteric (APG, 3-5% AAPB) Conditioning Benamidopropyl dimethylamine 2-5% agents Polishing Natural oils and derivatives 1-5% agents (without silicones) Speciality Active ingredients and 1-5% products functional substances Restructuring Polymers, cationic copolymers 1-3% agents Base solvent Water As needed at 100 Fragrance Perfume As needed

TABLE-US-00004 Hair restructuring cream (reconstruction) Function Ingredient Concentration Emulsifier Cetyl cystearyl alcohol 5% composition Polyglycerol stearate 4% phosphate Sorbitan monostearate 1% Active Keratin, chitin, cysteine etc. 5% substances Functional Nutrients, moisturisers, 5% substances plasticisers Conditioners Quaternary, cationic 4-6%   homopolymers Specialising Copolymer amino acids and 4% substances silanes Antioxidant Sodium hydrosulphite 0.5%  Chelating agent Sequestrant 0.1%  Basic solvent Water, ethyl alcohol As needed at 100 Fragrance Perfume As needed

[0107] All oxidising colouring products consist of two components: the first alkaline component, the dye, containing the colour precursors, and the second component, the oxidising emulsion (detector). A few minutes before application to the hair, the two components are mixed together, triggering a chemical reaction that creates the desired colour shade.

[0108] In the hair colouring process, hydrogen peroxide is therefore used as a means of decolouration or oxidation. It is used in emulsified form because, once combined with the dye, it must form a homogeneous compound with a viscosity that favours contact and adhesion to the hair, avoiding dripping on the face and neck. The possibility of producing emulsified hydrogen peroxide in a “green” version makes it possible to carry out an entire colouring process without polyethylene glycol derivatives.

TABLE-US-00005 Emulsified hydrogen peroxide Concentration Function Ingredient 12 vol. 20 vol. 40 vol. Emulsifier Cetylstearyl alcohol .sup. 2% .sup. 2% 2.5% composition Polyglycerol/fatty 1.5% .sup. 2% 2.0% acid phosphate Lauryl alcohol 0.5% 0.5% 1.0% Oxidant Hydrogen peroxide  10%  18%  34% (H2O2) 36%. Stabilisers Oxyquiniline, Na 0.5% 0.5% 0.5% pyrophosphate etc. pH corrector Phosphoric acid 0.5% 0.5% 0.5% solution etc. Water Water  85%  76%  59%

Effectiveness Tests

[0109] As proof of the validity of the emulsifying composition based on polyglycerol phosphate, we present a photographic comparison of the results obtained with the same hair dye formulated both with a traditional type of emulsifying composition containing ethoxylates (comparison example), and with a “Peg free” emulsifying composition (free of polyethylene glycols) according to the teachings in the patent.

[0110] The two dyes were formulated with an equal amount of emulsifying composition, were made by the same preparation method and contain the same amount of dyes, ingredients and excipients.

[0111] The effectiveness of the new solution was tested with the black dye (shade 1.0), a colour that is more difficult to prepare and stabilise than dyes of other colours due to the chemical nature of the dyes and their high concentration. In addition, an incorrectly made dark dye clearly shows defects in coverage and colour uniformity.

[0112] The experimentation was carried out by applying the two products using the same method to hair divided into two parts: on the left the traditional dye, on the right the innovative dye.

TABLE-US-00006 Hair dye comprising polyoxyethylene emulsifiers (COMPARISON EXAMPLE) Function Ingredient Concentration Emulsifier Cetylstearyl alcohol 15%  composition Cetyltistearyl alcohol (20)OE 8% Cetylstearyl alcohol (3)OE 4% Glyceryl monostearate 3% Primary dye Toluene-2,3-diamine sulphate 4% Secondary dye Pigments, resorcinol 4% Plus Special substances (oils, max. 5% emollients, active ingredients) Alkalinising Ammonia, amines etc. max. 6% Antioxidant Sodium hydrosulphite 0.2%  Chelating Sequestrant 0.1%  Basic Solvent Water 40-50%   Fragrance Perfume As needed Surfactant Amphoteric, non-ionic or max. 5% anionic Secondary Glycols or other max. 5% solvent

TABLE-US-00007 Hair dye comprising a polyglycerol phosphate aliphatic ester as emulsifier Function Ingredient Concentration Emulsifier Cetyl stearyl alcohol 15%  composition Polyglycerol stearate 12%  phosphate Glyceryl monostearate 3% Primary dye Toluene-2,3-diamine 4% sulphate Secondary dye Pigments, resorcinol 4% Plus Special and functional max. 5% substances (oils, emollients, active ingredients) Alkalinising Ammonia, amines etc. max. 6% Antioxidant Sodium hydrosulphite 0.2%  Chelating Sequestrant 0.1%  Basic solvent Water 40-50%   Fragrance Perfume As needed Surfactant Amphoteric, non-ionic max. 5% or anionic Secondary Propanediol or other max. 5% solvent

[0113] Preparation method: The method for preparing any of the emulsifying compositions listed above is always the same:

[0114] The aqueous and fatty phases are brought to the same temperature, so that the fatty phase is completely dissolved.

[0115] Subsequently, the aqueous and fatty phases are united by mechanical action, ensuring that all hydrophilic substances are first dissolved in water and then all hydrophobic substances are dissolved in the fatty phase (with the exception of heat-sensitive components, which can be added at the end of the emulsion when the temperature falls below the critical level).

[0116] Once a good dispersion of one phase in the other is obtained, proceed with the gradual cooling, until the desired consistency and appearance is obtained.