Use of polyol esters as preservatives

Abstract

The invention relates to an ester mixture obtained by esterification of at least one C2-C4 diol or one C3-C4 triol with an acid mixture comprising at least one saturated C2-C9 acid and 10-undecylenic acid. The invention also relates to the use of an ester mixture obtained by esterification of at least one polyol and an acid mixture comprising at least one saturated C2-C9 acid and 10-undecylenic acid as a preservative.

Description

Field of the Invention

[0001] The present invention relates to the use of an ester mixture obtained by esterification of a mixture of polyols and fatty acids as a preservative.

[0002] It is known to add preservatives to all types of synthetic or natural formulations. These have the purpose of preventing any proliferation of microorganisms such as bacteria, yeasts or fungi. This is because, after opening the product, the contact of the product with the external environment (such as air, humidity or heat) will tend to promote the occurrence of microbial proliferation. These preservatives must have fungicidal, bactericidal and yeasticidal activity, while being inert with respect to the other components of the added composition.

[0003] Therefore, regardless of the industrial sector, preservatives are added to products to avoid their degradation. In addition, it is required that this preservation action persists over time so that the product can be marked with an expiration date.

[0004] Therefore, this research field is important because it affects the sale of products as well as their lifespan.

[0005] Many studies have been carried out in this field and many products with very different structures are currently being used. For example, water-based paints or detergents are usually added with substances such as isothiazolinone derivatives. Soluble oils used as metallurgical fluids, for their part, will use compounds such as boric acid or cresol. In the cosmetic field, parabens and their derivatives, phenoxyethanol or methylisothiazolinone (known by the name MIT) have been or are very widely used.

[0006] However, some of these chemical substances used as preservatives are classified as skin sensitizers and can cause allergic reactions in users, and even more harmful others are classified as toxic or even carcinogenic.

[0007] In the cosmetic field, certain esters with specific structures are known to have the required safety properties. These data are published in the safety assessment section of the Cosmetic Ingredient Review.

[0008] Therefore, research in this field is continuous in order to provide manufacturers with new compounds described as multifunctional, that is to say exhibiting antimicrobial activity, as well as interesting physicochemical properties, that is to say allowing the compound to be easily added to any industrial product.

[0009] In addition, recent restrictions concern the sources of these new compounds. Especially in the cosmetic field, natural products, i.e. biogenic products, are sought.

[0010] Therefore, the object of the present invention is to propose new preservatives that are easy to use and are all or partially biogenic. Summary of the Invention

[0011] Thus, one subject of the present invention is an ester mixture obtained by the esterification of at least one C2-C4 diol or a C3-C4 triol with a fatty acid mixture comprising at least one saturated C2-C9 acid and 10-undecenoic acid.

[0012] The present invention also relates to a cosmetic composition comprising a cosmetically acceptable solvent and, relative to the total weight of the composition, from 0.1% to 25% by weight of an ester mixture as defined above.

[0013] The present invention also relates to the use of an ester mixture as a preservative, said ester mixture being obtained by the esterification of at least one polyol with a fatty acid mixture comprising at least one saturated C2-C9 acid and 10-undecenoic acid.

[0014] Finally, the present invention relates to a process for preparing the ester mixture according to the present invention.

[0015] Other advantageous features of the present invention are as follows:

[0016] - The saturated C2-C9 acid is selected from acetic acid, propionic acid, butyric acid, n-valeric acid, n-caproic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, especially n-heptanoic acid;

[0017] - The diols are selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, and the triols are selected from glycerol, 1,2,3-butanetriol and mixtures thereof;

[0018] - The mixture is obtained by the esterification of at least one diol or triol as defined above with an acid mixture comprising only one saturated C2-C9 acid and 10-undecenoic acid, the saturated C2-C9 acid being n-heptanoic acid;

[0019] - The mixture is obtained by the esterification of glycerol, n-heptanoic acid and 10-undecenoic acid;

[0020] - The mass ratio of one or more saturated C2-C9 acids to 10-undecenoic acid is from 1:10 to 10:1, preferably from 8:2 to 2:8, more particularly 7:3;

[0021] - The mass ratio of the diol or triol to the acid mixture is in the range from 1:4 to 1:10, and preferably, the mass ratio of the diol or triol to the acid mixture is 1:5;

[0022] - The saturated C2-C9 acid is selected from acetic acid, propionic acid, butyric acid, n-valeric acid, n-caproic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, especially n-heptanoic acid;

[0023] - The polyol contains a linear, branched or cyclic C2-C1600 hydrocarbon chain optionally interrupted by oxygen atoms and optionally 2 to 12 alcohol functional groups;

[0024] - The polyol is selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, pentanediol, 1,5-pentanediol, isopentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,7-heptanediol, octanediol, 1,8-octanediol, butylethylpropanediol, 2,4-diethyl-1,5-pentanediol, phytanetriol, decanediol, 1,10-decanediol, glycerol, 1,2,3-butanetriol, neopentyl glycol, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, sorbitol, erythritol, xylitol, mannitol, maltose, lactose, sucrose, raffinose, maltotriose, polyglycerol of the following formula (I):

[0025] [Chemical formula 1]

[0026]

[0027] where n represents an integer between 1 and 10;

[0028] polyethylene glycol of the following formula (II):

[0029] [Chemical formula 2]

[0030]

[0031] where n represents an integer between 2 and 800;

[0032] polypropylene glycol of the following formula (III):

[0033] [Chemical formula 3]

[0034]

[0035] where n represents an integer between 2 and 69;

[0036] and mixtures thereof;

[0037] - The ester mixture is obtained by esterification of the polyol as defined above and an acid mixture containing only one saturated C2-C9 acid and 10-undecenoic acid, and the saturated C2-C9 acid is n-heptanoic acid;

[0038] - The mass ratio of the polyol to the acid mixture is in the range of 1:4 to 1:10, and preferably, the mass ratio of the polyol to the acid mixture is 1:5;

[0039] - The polyol is derived from renewable resources, especially castor oil;

[0040] - The mixture is present in a cosmetic composition;

[0041] - The mixture is present in synthetic lubricant formulations, paints, especially waterborne paints, adhesives, sealant products, coating products, products for treating non-metallic surfaces, products for treating wood, detergents, fragrances, agrochemical formulations, formulations for the paper industry, hydraulic fracturing drilling formulations, battery liquid formulations;

[0042] - A method for preparing a mixture as defined above, comprising the following successive steps:

[0043] - A step of bringing a diol, triol or polyol into contact with an excess of an acid mixture as defined above,

[0044] - A step of heating the mixture to a temperature of 170 to 250 °C under reduced pressure in 3 to 10 stages. DETAILED DESCRIPTION

[0045] Other features, aspects, subjects and advantages of the present invention will become more clearly apparent by reading the following description.

[0046] It is stipulated that the expressions "from... to..." and "between... and..." used in this specification should be understood to include each of the recited limits.

[0047] For the purposes of the present invention, the term "preservative" should be understood to mean a compound having antimicrobial activity, intended to prevent the development of microorganisms (bacteria, yeasts and moulds). These antimicrobial preservatives are necessary to protect cosmetics from contamination. The antimicrobial protection of cosmetics can be evaluated according to standard ISO 11930, which consists of bringing the cosmetic into contact with 5 known microbial strains and evaluating the concentration of the remaining microorganisms at regular intervals over a period of 28 days.

[0048] The requirements in the field of cosmetics established by standard ISO 11930 apply to other technical fields and in no way prevent the use of preservatives in other technical fields.

[0049] Ester mixture

[0050] The ester mixture according to the present invention is obtained by the esterification of at least one C2-C4 diol or one C3-C4 triol with an acid mixture comprising at least one saturated C2-C9 fatty acid and 10-undecenoic acid.

[0051] Thus, depending on the number of hydroxyl functional groups in the polyol, i.e. whether it is a diol or a triol, and depending on the proportion of each acid contained in the mixture, the latter will be differently distributed on the polyol chain, thereby producing an ester mixture.

[0052] The diol is selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, and the triol is selected from glycerol, 1,2,3-butanetriol, and mixtures thereof.

[0053] The saturated C2-C9 acids are selected from acetic acid, propionic acid, butyric acid, n-valeric acid, n-caproic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, especially n-heptanoic acid.

[0054] The mass ratio of one or more saturated C2-C9 acids to 10-undecenoic acid can be from 1:10 to 10:1, preferably from 8:2 to 2:8, more especially 7:3.

[0055] The mass ratio of the polyol to the acid mixture can range from 1:4 to 1:10, and preferably, the mass ratio of the polyol to the acid mixture is 1:5.

[0056] Preferably, only one saturated acid is used to obtain the mixture according to the invention.

[0057] Preferably, the ester mixture according to the invention comprises:

[0058] - triglycerides having 3 units derived from saturated C2-C9 acids, by weight 30% to 50% relative to the total weight of the mixture,

[0059] - mixed triglycerides having 2 units derived from saturated C2-C9 acids and 1 unit derived from 10-undecenoic acid, by weight 30% to 50% relative to the total weight of the mixture,

[0060] - mixed triglycerides having 1 unit derived from saturated C2-C9 acids and 2 units derived from 10-undecenoic acid, by weight 10% to 20% relative to the total weight of the mixture, and

[0061] - triglycerides having 3 units derived from 10-undecenoic acid, by weight 0.5% to 5% relative to the total weight of the mixture.

[0062] Preferably, the mixture is obtained by esterification of glycerol, n-heptanoic acid, and 10-undecenoic acid.

[0063] Preferably, the ester mixture according to the invention comprises:

[0064] - triglycerides having 3 units derived from n-heptanoic acid, by weight 30% to 50% relative to the total weight of the mixture,

[0065] - From 30% to 50% by weight, relative to the total weight of the mixture, of a mixed triester having 2 units derived from n - heptanoic acid and 1 unit derived from 10 - undecenoic acid,

[0066] - From 10% to 20% by weight, relative to the total weight of the mixture, of a mixed triester having 1 unit derived from n - heptanoic acid and 2 units derived from 10 - undecenoic acid, and

[0067] - From 0.5% to 5% by weight, relative to the total weight of the mixture, of a triester having 3 units derived from 10 - undecenoic acid.

[0068] Composition

[0069] The present invention also relates to a cosmetic composition comprising a cosmetically acceptable medium and from 0.1% to 25% by weight, relative to the total weight of the composition, of an ester mixture as defined above.

[0070] The cosmetically acceptable medium may generally comprise water or a mixture of water and at least one organic solvent to dissolve compounds that are not sufficiently soluble in water.

[0071] More particularly, these organic solvents are selected from straight - chain or branched, preferably saturated, monohydric or dihydric alcohols having from 2 to 10 carbon atoms, such as ethanol, isopropanol, and 1,3 - propanediol, 1,2 - butanediol, 1,4 - butanediol, 2,3 - butanediol, methylpropanediol, 1,5 - pentanediol, 1,2 - hexanediol, 1,6 - hexanediol, and 3 - methyl - 1,5 - pentanediol; aromatic alcohols, such as benzyl alcohol, phenylethyl alcohol; diols or diol ethers, such as ethylene glycol or its monomethyl ether, monoethyl ether, and monobutyl ether, propylene glycol (1,2 - propylene glycol) or its ethers, such as propylene glycol monomethyl ether, butylene glycol (1,3 - butylene glycol), dipropylene glycol, pentylene glycol (1,2 - pentylene glycol), hexylene glycol (2 - methyl - 2,4 - pentanediol); and diethylene glycol alkyl ethers, which are especially C1 - C4, such as diethylene glycol monoethyl ether or monobutyl ether, alone or in mixture. These common solvents, if they are present, generally represent from 1% to 40% by weight, more preferably from 5% to 30% by weight, of the total weight of the composition.

[0072] The composition used according to the present invention generally comprises water or a mixture of water and one or more organic solvents or a mixture of organic solvents. The composition according to the present invention preferably comprises water. Preferably, the water content is in the range of from 5% to 95% by weight, more preferably from 10% to 90% by weight, still better from 20% to 80% by weight, relative to the total weight of the composition.

[0073] The composition according to the invention may also contain various additives conventionally used in cosmetic compositions, such as mineral thickeners and, in particular, fillers such as clay or talc; organic thickeners, silicones, antioxidants, penetrants, humectants, emollients other than the mixture of the invention, gelling agents, stabilizers, chelating agents, fragrances, dispersants, film-forming agents, ceramides, preservatives other than the mixture of the invention, opacifiers, fatty substances, pH regulators, colorants, vitamins, odor absorbers, essential oils, fruit and plant extracts, surfactants, emulsifiers and mixtures thereof.

[0074] The above additives are generally present in amounts by weight, relative to the weight of the composition, between 0.01% and 40% by weight, preferably between 0.1% and 20% by weight relative to the weight of the composition.

[0075] Use

[0076] The invention also relates to the use of an ester mixture as a preservative, said ester mixture being obtained by esterification of at least one polyol with an acid mixture comprising at least one saturated C2-C9 acid and 10-undecenoic acid.

[0077] Advantageously, the polyol may comprise a linear, branched or cyclic C2-C1600 hydrocarbon chain optionally interrupted by oxygen atoms and optionally 2 to 12 alcohol functional groups.

[0078] The polyol is preferably selected from ethylene glycol (also known as ethane diol), 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, pentanediol (also known as 1,2-pentanediol), 1,5-pentanediol, isopentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,7-heptanediol, octanediol, 1,8-octanediol, butylethylpropanediol, 2,4-diethyl-1,5-pentanediol, phytanetriol, decanediol, 1,10-decanediol, glycerol, 1,2,3-butanetriol, neopentyl glycol, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, sorbitol, erythritol, xylitol, mannitol, maltose, lactose, sucrose, raffinose, maltotriose and mixtures thereof.

[0079] The polyol may also be a polyglycerol of the following formula (I):

[0080] [Chemical formula 4]

[0081]

[0082] wherein n represents an integer between 1 and 10.

[0083] The polyol may also be a polyethylene glycol of the following formula (II):

[0084] [Chemical formula 5]

[0085]

[0086] Wherein n represents an integer between 2 and 800.

[0087] The polyol can also be polypropylene glycol of the following formula (III):

[0088] [Chemical formula 6]

[0089]

[0090] Wherein n represents an integer between 2 and 69.

[0091] The saturated C2-C9 acid is as defined above.

[0092] Preferably, the ester mixture is obtained by the esterification of at least one polyol with an acid mixture comprising heptanoic acid and 10-undecenoic acid; more particularly, the ester mixture is obtained by the esterification of glycerol, heptanoic acid and 10-undecenoic acid.

[0093] Preferably, the mass ratio of one or more saturated C2-C9 acids to 10-undecenoic acid is from 1:10 to 10:1, preferably from 8:2 to 2:8, and more particularly 7:3.

[0094] Preferably, the mass ratio of the polyol to the acid mixture is in the range of 1:4 to 1:10, and preferably, the mass ratio of the polyol to the acid mixture is 1:5.

[0095] Finally, the ester mixture used according to the present invention may include an acid derived from renewable resources.

[0096] Preferably, the acid can be derived from castor oil. Castor oil is obtained by a conventional extraction method, and then the methanolysis of the oil enables the production of an ester fraction rich in methyl ricinoleate (≥75%), which is subjected to thermal cracking and then distilled. The thermal cracking produces a C11 fraction comprising methyl undecenoate and a C7 fraction comprising heptanal, the C11 fraction producing 10-undecenoic acid (C11:1) upon hydrolysis, and the C7 fraction producing heptanoic acid (C7) upon oxidation. This method is disclosed in the scientific publication OCL, Volume 16, Issue 4, July - December 2009.

[0097] It has been observed that this ester mixture exhibits effective antimicrobial activity.

[0098] In addition, it has an emollient effect, which is particularly advantageous in the cosmetic field. Thus, it has the advantage of itself producing two properties required for, for example, a cream, namely an antimicrobial action and an emollient action.

[0099] Finally, the ester mixture according to the invention has the advantage of remaining liquid at low temperatures. In particular, it is beneficial for its storage conditions and improves logistics constraints.

[0100] Preferably, the ester mixture based on polyols and fatty acids according to the invention can be used in cosmetic formulations as a preservative and emollient at a concentration of from 0.01% to 50% by weight, preferably from 0.1% to 25% by weight, relative to the total weight of the composition.

[0101] The mixtures as defined above can be present in synthetic lubricant formulations, paints, especially aqueous paints, adhesives, sealant products, coating products, products for treating non-metallic surfaces, products for treating wood, detergents, perfumes, agrochemical formulations, formulations for the paper industry, hydraulic fracturing drilling formulations, battery liquid formulations.

[0102] The ester mixture based on polyols and fatty acids can be used in industrial formulations for its lubricating and anti-corrosion properties at a concentration of from 0.01% to 99% by weight, preferably from 0.1% to 95% by weight, relative to the total weight of the composition.

[0103] Method

[0104] The invention also relates to a method for synthesizing the above ester mixture. The mixture can be obtained according to the method described in document FR3112344. This method has the advantage of not using a catalyst.

[0105] The method comprises the following successive steps:

[0106] - a step of bringing the polyol into contact with an excess of acid mixture,

[0107] - a step of heating the mixture to a temperature of from 170 to 250 °C, preferably from 210 to 240 °C, under partial vacuum in 3 to 10 stages, preferably 3 to 6 stages.

[0108] The presence of an excess of acid mixture during the contact step allows for a good distribution of the acid along the polyol chain. This molar excess can be at least 30% of the acid mixture relative to the polyol. For example, this molar excess can be 30% to 35%, or 35% to 40%, or 40% to 45%, or 45% to 50% of the acid mixture relative to the polyol.

[0109] This contact step can be carried out without a solvent.

[0110] Preferably, the step of bringing the polyol into contact with the acid mixture can be carried out completely or partially under an inert atmosphere, for example under a nitrogen or argon atmosphere.

[0111] Next, the method of the present invention includes the step of heating a mixture of a polyol and an acid mixture (or in other words, the reaction medium) at a temperature of 180 to 270 °C, preferably 200 to 250 °C. The temperature range depends on the selected ester mixture and their boiling points. This temperature can be, for example, 180 to 185 °C; or 185 to 190 °C; or 190 °C to 195 °C; or 195 to 200 °C; or 200 to 205 °C; or 205 to 210 °C; or 210 to 215 °C; or 215 to 220 °C; or 220 to 225 °C; or 225 to 230 °C.

[0112] This step can have a duration of 3 to 20 hours and preferably 6 to 12 hours. Thus, the duration can be 3 to 5 hours, or 5 to 7 hours, or 7 to 9 hours, or 9 to 11 hours, or 11 to 13 hours, or 13 to 15 hours, or 15 to 17 hours, or 17 to 20 hours.

[0113] Preferably, the heating step is carried out gradually, continuously or in stages under partial vacuum.

[0114] This partial vacuum can be 0.5 to 750 mbar, preferably 1 to 500 mbar, or it can also be 1 to 150 mbar, more preferably 1 to 50 mbar.

[0115] The stepwise reduction to partial vacuum can be adjusted according to the desired yield and purity to be achieved, as shown in the experimental section below.

[0116] Due to the different boiling points of the acids, the stepwise reduction of pressure enables the preferential distillation of one acid without damaging another acid, and thus allows for a uniform and targeted distribution on the polyol chain according to the mass ratio of the acids used.

[0117] A Vigreux column with vacuum suction can be used.

[0118] This step of heating and placing under vacuum will enable the removal of the water generated during the esterification reaction. In addition, the excess acid will be able to be removed and recycled.

[0119] Then the crude product obtained after or before cooling can be separated and preferably purified to remove the excess acid and also the impurities present in the crude product, such as esters containing free hydroxyl functional groups that have not reacted with the acid.

[0120] The method according to the present invention enables the obtaining of the desired crude product with an esterification degree greater than or equal to 95% by ester. Thus, the esterification degree can be 95% to 96%, or 96% to 97%, or 97% to 98%, or 98% to 99%, or greater than 99%.

[0121] Thus, the method according to the invention may include a step that enables the removal of the excess acid. This step is preferably a distillation step. According to other embodiments, after the reaction and heating steps are completed, the crude product is not separated, but the step that enables the removal of the excess acid is directly carried out. In this case, the pressure can be reduced to a value less than 1 mbar to continue distilling the excess acid.

[0122] The invention also relates to an ester mixture obtainable by the method as defined above.

[0123] Another subject of the invention is an ester mixture directly obtained by the method as defined above.

[0124] The following examples illustrate the invention but do not limit the invention in any way.

[0125] Examples

[0126] Comparative tests were carried out to demonstrate the antimicrobial effect of the ester mixture according to the invention.

[0127] 1. Preparation of the ester mixture

[0128] 1.1. Ester mixture according to the invention: A triglyceride of heptanoic acid and undecylenic acid (70 / 30) An ester mixture of heptanoic acid and undecylenic acid with triglyceride was prepared according to the following method.

[0129] Glycerol (purity > 99%), n-heptanoic acid ( purity > 99%) and undecylenic acid ( purity > 97%) were charged into a 1 L three-necked glass flask equipped with a stirrer, a temperature probe, a Vigreux column, a reflux condenser, and an inlet for inerting with nitrogen.

[0130] The mass ratio of heptanoic acid / undecylenic acid was 70 / 30, and the total molar excess of acid relative to glycerol was at least 30%.

[0131] The reaction mixture was stirred at 800 rpm, degassed under vacuum for 30 min, and then placed under a nitrogen atmosphere. The medium was heated to a temperature of 220 °C for a duration of 4 hours until the theoretical amount of water to be collected was stable. The assembly was placed under a progressive vacuum from atmospheric pressure to 450 mbar, and then the stages of 300 mbar, 200 mbar, and 150 mbar were maintained, with the final stage at 20 mbar, to distill the unreacted excess acid.

[0132] 339 g of the crude product was recovered and treated with in-situ activated basic alumina in a three-necked flask under stirring and under a nitrogen atmosphere at ambient temperature. The mixture was then filtered under vacuum through a 0.2 μm Millipore filter. 276 g (total yield 85%) of the treated product was collected in the form of a colorless liquid.

[0133] The ester obtained has the following formula:

[0134] [Chemical formula 7]

[0135]

[0136] where R = -(CH2)5CH3 and -(CH2)8-CH=CH2, in a ratio of 70 / 30

[0137] 1.2. Comparative mixture 1: Triheptanoin

[0138] Triheptanoin is sold by Stéarinerie Dubois under the trade name DUB THG. Triheptanoin has the following formula:

[0139] [Chemical formula 8]

[0140]

[0141] where R = -(CH2)5CH3

[0142] 1.3. Comparative mixture 2: Triglycerides of caprylic acid and capric acid in a (55 / 45) mass ratio

[0143] Triglycerides of caprylic acid and capric acid are sold by Stepan under the trade name M-5 Cosmetic. Triglycerides of caprylic acid and capric acid have the following formula:

[0144] [Chemical formula 9]

[0145]

[0146] where R = -(CH2)6CH3 and R = -(CH2)8CH3, in a ratio of 55 / 45

[0147] 2. Evaluation of the mixture

[0148] The antimicrobial efficacy of the ester mixture was evaluated by a challenge test according to Standard ISO 11930-2019.

[0149] The test consists of bringing the pathogenic organisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus brasiliensis into contact with the component to be tested and regularly counting the variation in the number of microorganisms compared to the control inoculum over a period of 28 days. The protocol of standard ISO 11930 - 2019A is strictly followed. Table 1 below lists the evaluation criteria that appear in Annex B of the standard.

[0150] [Table 1]

[0151]

[0152]

[0153] Standard A corresponds to the recommended level of efficacy and, when non - compliance with Standard A demonstrates a microbiological risk, Standard B applies. NI stands for "No Increase compared to the previous time".

[0154] Results of the ester mixture according to the present invention

[0155] Count

[0156] [Table 2]

[0157]

[0158] D represents the count, i.e., the number of colonies present on the incubation plate.

[0159] Log reduction obtained

[0160] [Table 3]

[0161]

[0162]

[0163] Under the test conditions, the antimicrobial preservation of the product is sufficiently effective against the 5 strains tested. The product complies with Standard A of standard NF EN ISO 11930 (February 2019).

[0164] Results for triheptanoin (Comparative Example 1)

[0165] Count

[0166] [Table 4]

[0167]

[0168] Logarithmic reduction obtained

[0169] [Table 5]

[0170]

[0171] In the table, A indicates an increase compared to the previous time, and I indicates an increase compared to the inoculum.

[0172] For all the tested strains, the product was non - compliant starting from 7 days and 14 days.

[0173] Under the test conditions, the antimicrobial preservation of the product was not effective enough for the 5 tested strains. The product did not meet the standard criteria A and B.

[0174] Results of triglycerides of caprylic and capric acids (Comparative Example 2)

[0175] Count

[0176] [Table 6]

[0177]

[0178]

[0179] Logarithmic reduction obtained

[0180] [Table 7]

[0181]

[0182] For all the tested strains, the product was non - compliant starting from 7 days and 14 days.

[0183] Under the test conditions, the antimicrobial preservation of the product was not effective enough for the 5 tested strains. The product did not meet the standard criteria A and B.

[0184] Measurement of pour point

[0185] The pour point expressed in °C was measured according to standard ISO 3016.

[0186] [Table 8]

[0187]

[0188] In summary, the ester mixture according to the present invention has antimicrobial properties that are far superior to those obtained with comparative mixtures 1 and 2. In addition, the mixture according to the present invention has a lower pour point than the other mixtures and can thus be used at much more extreme temperatures.

Claims

1. An ester mixture obtained by the esterification of at least one C2-C4 diol or one C3-C4 triol with an acid mixture comprising at least one saturated C2-C9 acid and 10-undecenoic acid.

2. The mixture according to claim 1, characterized in that The saturated C2-C9 acid is selected from acetic acid, propionic acid, butyric acid, n-valeric acid, n-caproic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, especially n-heptanoic acid.

3. The mixture according to claim 1 or 2, characterized in that, The diols are selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, and the triols are selected from glycerol, 1,2,3-butanetriol and mixtures thereof.

4. The mixture according to any one of claims 1 to 3, characterized in that, The mixture is obtained by the esterification of at least one diol or triol as defined in claim 1 or 2 with an acid mixture comprising only one saturated C2-C9 acid and 10-undecenoic acid, the saturated C2-C9 acid being n-heptanoic acid.

5. The mixture according to any one of claims 1 to 4, characterized in that It is obtained by the esterification of glycerol, n-heptanoic acid and 10-undecenoic acid.

6. The mixture according to any one of claims 1 to 5, characterized in that The mass ratio of the saturated C2-C9 acid to 10-undecenoic acid is from 1:10 to 10:1, preferably from 8:2 to 2:8, more particularly 7:

3.

7. The mixture according to any one of claims 1 to 6, characterized in that The mass ratio of the diol or triol to the acid mixture is from 1:4 to 1:10, and preferably the mass ratio of the diol or triol to the acid mixture is 1:

5.

8. A cosmetic composition comprising a cosmetically acceptable solvent and from 0.1% to 25% by weight, based on the total weight of the composition, of an ester mixture as defined in any one of claims 1 to 7.

9. Use of an ester mixture as a preservative, the ester mixture being obtained by the esterification of at least one polyol and an acid mixture comprising at least one saturated C2-C9 acid and 10-undecenoic acid.

10. The use according to claim 9, characterized in that The saturated C2-C9 acid is selected from acetic acid, propionic acid, butyric acid, n-valeric acid, n-caproic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, especially n-heptanoic acid.

11. The use according to claim 9 or 10, characterized in that, The polyol comprises a straight-chain, branched-chain or cyclic C2-C1600 hydrocarbon chain optionally interrupted by oxygen atoms, and optionally from 2 to 12 alcohol functional groups.

12. The use according to claim 11, wherein The polyols are selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, butanediol, 1,2-butanediol, 2,3-butanediol, methylpropanediol, pentanediol, 1,5-pentanediol, isopentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 1,7-heptanediol, octanediol, 1,8-octanediol, butylethylpropanediol, 2,4-diethyl-1,5-pentanediol, phytanetriol, decanediol, 1,10-decanediol, glycerol, 1,2,3-butanetriol, neopentyl glycol, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, sorbitol, erythritol, xylitol, mannitol, maltose, lactose, sucrose, raffinose, maltotriose, polyglycerol of the following formula (I): [Chemical formula 10] wherein n represents an integer between 1 and 10; polyethylene glycol of the following formula (II): [Chemical formula 11] wherein n represents an integer between 2 and 800; polypropylene glycol of the following formula (III): [Chemical formula 12] wherein n represents an integer between 2 and 69; and mixtures thereof.

13. Use according to any one of claims 9 to 12, characterized in that, The ester mixture is obtained by esterification of a polyol as defined in claim 9, 11 or 12 with an acid mixture comprising only one saturated C2-C9 acid and 10-undecenoic acid, the saturated C2-C9 acid being n-heptanoic acid.

14. The use according to any one of claims 9 to 13, characterized in that, The ester mixture is obtained by esterification of glycerol, n-heptanoic acid and 10-undecenoic acid.

15. The use according to any one of claims 9 to 14, characterized in that, The mass ratio of the saturated C2-C9 acid to 10-undecenoic acid is from 1:10 to 10:1, preferably from 8:2 to 2:8, and more particularly 7:

3.

16. The use according to any one of claims 9 to 15, characterized in that, The mass ratio of the polyol to the acid mixture is in the range from 1:4 to 1:10, and preferably, the mass ratio of the polyol to the acid mixture is 1:

5.

17. The use according to any one of claims 9 to 16, characterized in that, The polyol is derived from renewable resources, in particular castor oil.

18. The use according to any one of claims 9 to 17, characterized in that, The mixture is present in a cosmetic composition.

19. The use according to any one of claims 9 to 17, characterized in that, The mixture is present in synthetic lubricant formulations, paints, in particular waterborne paints, adhesives, sealant products, coating products, products for treating non-metallic surfaces, products for treating wood, detergents, fragrances, agrochemical formulations, formulations for the paper industry, hydraulic fracturing drilling formulations, battery liquid formulations.

20. A method for preparing a mixture as defined in claims 1 to 7, or 9 to 17, comprising the following successive steps: - a step of bringing a diol, triol or polyol into contact with an excess of an acid mixture as defined in claims 1 to 7, or 9 to 17, - a step of heating the mixture to a temperature of 170 to 250 °C under a partial vacuum reduced in 3 to 10 stages.

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