Fatty acid salt

Abstract

The present invention relates to a method for producing a composition comprising fatty acid salts, preferably salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid, comprising the steps of: a) providing a composition comprising - at least one short-chain fatty acid and / or an ester thereof, and - at least one medium-chain fatty acid and / or an ester thereof, and / or - at least one long-chain fatty acid and / or an ester thereof, b) incubating the composition of step a) with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide thereby forming solid particles comprising said at least one polymeric guanidine and said at least one short-chain fatty acid and c) removing the solid particles from the mixture of step b). The composition is free of malodorous reaction products like butyric acid and it is used as a soap, detergent or tenside.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the field of fatty acid salts and the production thereof.BACKGROUND ART

[0002] Fatty acid salts (soaps) are a widely used as anionic surfactants. The applications include the use in washing products, cosmetics as well as surface and toilet cleaners for household and personal cleaning. The process of producing fatty acid salts has been known since antiquity, when lye was leached from the ashes of a wood fire. Industrially, molten tallow is nowadays treated with an excess of alkali in large vats. The mixture is heated and after hydrolysis is complete, the fatty acid salts are precipitated by the addition of an inorganic salt, filtered, and washed by successive solution in water.

[0003] The sensory and chemical characteristics of fatty acid salts depends on the manufacturing process, and the chemical composition of the materials used. In particular, fatty acids play key roles in the performance and the quality of the fatty acid salt compositions, consumer preferences, and costs. It is known in the art that fatty acids and fatty acid-containing compositions often exhibit reactions like autoxidation or hydrolysis when exposed to air, light, moisture, or bacterial action leading to smelly or bad-tasting products. These effects relate to the presence of free fatty acids and in particular, malodorous short-chain fatty acids as reaction products. As consequence, short-chain fatty acids are released and unpleasant odor in the product develops. Additionally, short-chain fatty acids formed in fatty acid salts serve as catalysts themselves, further accelerating the reaction. Thus, the presence of short-chain fatty acids - a minor component of most fatty acid salt compositions - has a significant influence on the overall quality and sensory characteristics, and in turn, consumer preference or acceptance of fatty acid salt compositions such as e.g., soaps.

[0004] Butyric acid, in particular, has a strong, pungent odor that is often described as resembling rotten eggs or vomit. When present in soaps, it can contribute to an unpleasant smell that many people find off-putting. To address this issue, soap manufacturers take steps to minimize the presence of butyric acid in their products. This can involve using different oils or fats in the soap-making process, as well as employing specific techniques to reduce the formation or retention of these acids. However, all know methods are labor intensive and involve complex apparatuses.

[0005] It is an object of the present invention to provide a fatty acid salt composition which is free of malodorous reaction products like butyric acid.SUMMARY OF THE INVENTION

[0006] Thus, the present invention relates to a method for producing a composition comprising fatty acid salts, preferably salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid, comprising the steps of: a) providing a composition comprising at least one short-chain fatty acid and / or an ester thereof, and at least one medium-chain fatty acid and / or an ester thereof, and / or at least one long-chain fatty acid and / or an ester thereof, b) incubating the composition of step a) with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide thereby forming solid particles comprising said at least one polymeric guanidine and said at least one short-chain fatty acid and c) removing the solid particles from the mixture of step b) .

[0007] It turned surprisingly out that polymeric guanidine can be used to remove efficiently short-chain fatty acids from a composition comprising fatty acids of various lengths in a simple way resulting in a product which is essentially free from unpleasant odors caused by these short-chain fatty acids. Malodorous short-chain fatty acids and / or an ester thereof can be removed by incubating a composition comprising fatty acids with the alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide. Surprisingly, it turned out that the polymeric guanidine binds short-fatty fatty acids and / or an ester thereof when the alkaline composition is added to the composition of step a), forming polymeric particles which are insoluble when heated to a temperature at which salts of fatty acids, in particular salts of medium- and long-chain fatty acids, typically melt. The formed solid particles comprise said at least one polymeric guanidine and said at least one short-chain fatty acid. The solid particles are then removed from the reaction mixture of step b), wherein salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid remain in the obtained composition. The present invention therefore provides a facile method to produce fragrant and qualitative compounds comprising fatty acid salts.

[0008] The method of the present invention can also be used for removing short-chain fatty acids and / or salts of short-chain fatty acids from a composition comprising fatty acids of various lengths and / or esters and / or salts thereof. Such a method comprises the step of incubating a composition comprising salts of fatty acids with at least one polymeric guanidine thereby forming solid particles comprising said at least one polymeric guanidine and short-chain fatty acids comprised in said composition. The solid particles formed are removed from the mixture with known methods. If the composition comprising fatty acid salts is highly viscous or even solid, the composition may be heated to decrease its viscosity or even to melt it allowing the removal of the solid particles formed by the polymeric guanidine and the at least one short-chain fatty acids.

[0009] Another aspect of the present invention relates to a composition obtainable by the method as defined herein.

[0010] Yet another aspect of the present invention relates to the use of the composition as defined herein as a soap, detergent or tenside.

[0011] It further turned out that the composition according to the present invention is particularly useful in the area of cleaning agents, fabric conditioners, laundry additives or cosmetics. In domestic settings, the composition of the present invention can be used as soap for washing, bathing, and other types of housekeeping. In industrial settings, it can be used as thickener, component of lubricants, and precursor to catalysts. Since the composition used according to the invention decrease the surface tension of liquids, it also particularly function as emulsifier, wetting agent, detergent, foaming agent, or dispersant.DESCRIPTION OF PREFERRED EMBODIMENTS

[0012] The term "fatty acid", as used herein, refers to a carboxylic acid with an aliphatic chain.

[0013] "Short-chain fatty acids", as used herein, are fatty acids with aliphatic tails of six or fewer carbon atoms. According to a preferred embodiment of the present invention the at least one short-chain fatty acid has a chain length of 3 to 6 carbon atoms, preferably 3 or 4 carbon atoms. Preferably, the short-chain fatty acid is butyric acid.

[0014] The term "medium-chain fatty acids", as used herein, refers to fatty acids with aliphatic tails having a chain length of 6 to 12 carbon atoms.

[0015] "Long-chain fatty acids", as used herein, include fatty acids with aliphatic tails having a chain length of 13 to 22 carbon atoms.

[0016] The "composition comprising salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid" comprises at least 50 wt % to 99 wt %, preferably 55 wt% to 95 wt%, preferably 60 wt% to 90 wt%, preferably 65 wt% to 85 wt% of the salts of the at least one medium-chain fatty acid and / or the at least one long-chain fatty acid compared to the total weight of the composition. The composition produced by the method of the present invention is essentially free from short-chain fatty acids. In this context, "essentially free", means that the composition comprises less than 5 wt%, preferably less than 4 wt%, more preferably less than 3 wt%, more preferably less than 2 wt%, more preferably less than 1 wt%, more preferably less than 0.5 wt%, more preferably less than 0.2 wt%, more preferably less than 0.1 wt%, in particular 0 wt% short-chain fatty acids. Said composition can be obtained by the method according to the present invention.

[0017] According to another preferred embodiment of the present invention the composition of step a) comprises saturated and / or unsaturated fatty acids. As used herein, the term "saturated fatty acids" refers to fatty acids having no C=C double bonds and are defined by the formula CH 3 (CH 2 )nCOOH, wherein n can be any integer. "Unsaturated fatty acids", as used herein, mean fatty acids having one or more C=C double bonds. The C=C double bonds can give either cis or trans isomers. The unsaturated fatty acid, as used herein, are presented by the formula CH 3 (CH 2 )nCH=CH(CH 2 )nCOOH, wherein n can be any integer.

[0018] The composition of step a), in particular the fatty acids and / or salts thereof, can be of animal and / or vegetable origin. According to another preferred embodiment of the present invention the composition of step a) is at least one animal and / or vegetable fat and / or oil. Preferably, the least one animal fat can be part of milk, butter, tallow or lard. The at least one vegetable fat or oil can be coconut oil, grapeseed oil, hemp seed oil, olive oil, palm oil, rose hip oil, canola oil, cocoa butter and shea butter. The composition of step a) can be stirred and / or heated before proceeding with step b) to ensure a homogenous mixture and to avoid the occurrence of clumps.

[0019] According to the present invention the composition of step a) can be incubated with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide. According to another preferred embodiment of the present invention the composition of step a) and the alkaline composition are mixed in a weight ratio of between 10:1 to 1:1, preferably between 5:1 to 1:1, preferably between 2:1 to 1:1, preferably between 1.5:1 to 1:1. Surprisingly, it turned out that the solid particles can be efficiently formed by mixing the composition of step a) and the alkaline composition at a defined ratio. Preferably, the alkaline composition can be prepared separately before incubating with the composition of step a).

[0020] Polymeric guanidine is a cationic polymer which is usually used as antiseptic for e.g., textiles or room disinfectant in hospital settings. Polymeric guanidine is generally characterized by high-efficiency, good stability, high and thermal decomposition temperature and represents a non-toxic and non-irritating material. The polymer has become a major research topic in the field of sterilization in recent years. Due to its high activity, the guanidine group is positively charged and easily adsorbed by various types of bacteria and viruses that are usually negatively charged, thus resisting the functions of bacteria and viruses. The prior art also describes drugs which contain the polymeric guanidine derivatives as active ingredients, having an antimicrobial effect. Hence, the polymer can also be used in human medicine as well as in veterinary medicine to combat infections. Biocidal polymeric guanidine salts are known in the art. Chlorides of these polymers are prepared by reacting diamine, e.g., hexamethylene diamine or triethylene glycol diamine, with guanidine hydrochloride. This forms a cationic polymer (polyguanidinium cation) with chloride as counterion. For instance, this compound is known to possess pronounced biocidal properties. Other salts of polymeric guanidine can be prepared by using another salts of guanidine instead of hydrochloride. The salt of the at least one polymeric guanidine can be prepared with dihydrogen phosphate, carbonate, nitrate, dehydroacetate citrate, or preferably hydrochloride as counterion.

[0021] According to a preferred embodiment of the present invention the at least one polymeric guanidine is selected from the group consisting of polyhexamethylene guanidine (PHMG), poly(2-(2-ethoxy)-ethoxyethyl)-guanidine, polyhexamethylene biguanide (PHMB), polytriethylene glycol guanidine, polyethylene glycol guanidine, polyoxypropylene guanidine, polyaminopropyl biguanide (PAPB), methacryloyl guanidine, salts thereof and mixtures thereof.

[0022] It has been surprisingly turned out that polymeric guanidine can be used to remove short-chain fatty acids in fatty acid salt production. In particular, the counterion of the at least one polymeric guanidine (i.e., hydrochloride) can be exchanged with cations of the fatty acid salt, producing a salt as intermediate product. The cationic polymeric guanidine specifically binds short-chain fatty acids of the fatty acid salt and / or an ester thereof, forming insoluble particles, which can be removed according to the invention. Another advantage of the present invention is that the solid particles can be formed within several minutes and can be easily identified by eye.

[0023] According to another preferred embodiment of the present invention the alkaline mixture of step b) comprises 0.5 to 20 wt %, preferably 1 to 10 wt %, preferably 2 to 5 wt %, of the at least one polymeric guanidine.

[0024] According to another preferred embodiment of the present invention at least one alkali salt is added to the mixture of step b). When at least one alkali salt is added, the solubility of the mixture is reduced and it precipitates. This process of flocculation is also called "salting out". The precipitated mixture can be separated from (liquid) impurities such as excess lye, glycerin, and water. According to another preferred embodiment of the present invention the at least one alkali salt is selected from the group consisting of sodium chloride, potassium chloride and mixtures thereof.

[0025] To produce the composition according to the invention, fatty acids and / or esters thereof in fats, oils, used as feedstock are converted in the presence of least one alkali hydroxide to form fatty acid salts. According to another preferred embodiment of the present invention the at least one alkali hydroxide is selected from the group consisting of sodium hydroxide, potassium hydroxide and mixtures thereof.

[0026] Fatty acid salts can be produced by two main processes known in the art, the cold process, and the hot process.

[0027] The hot process involves combining a lye mixture with oils and / or fats. The mixture is heated to speed up the saponification process, which means the final products can be further processed within one day and used right away. However, the obtained composition can be stored, giving it the opportunity for the water to evaporate to create a harder, longer-lasting product. The hot process is commonly used for mass-production. Unlike the cold process, the essential oils, fragrances, and other additives are added after the chemical reaction is finished, which helps to preserve the benefits of the natural ingredients and the scents to last longer.

[0028] The cold process uses the heat generated from the combination of the fatty acids in the melted oils and fats with an alkaline solution to facilitate the saponification process, which takes several hours to complete, and weeks to cure the finished product. The mixture can be slightly warmed to achieve a homogenous mixture. One of the main benefits of the cold process is having complete control over the ingredients, having no added detergents which can e.g., strip off the skin's natural oils. Since cold process does not rely on heat, it is easier to maintain the efficacy of the natural properties of active ingredients like natural and essential oils. The mixture of step b) can be incubated at a temperature ranging from 5°C to 100°C, allowing the use of a cold or a hot process to produce the composition according to the present invention. According to a preferred embodiment of the present invention step b) is conducted at a temperature ranging from 5°C to 100°C, preferably from 10°C to 90°C, more preferably from 20°C to 80°C, more preferably from 30°C to 70°C. This is particularly advantageous, since the properties of the final product can be individually adapted, depending on the process used.

[0029] Thus, the incubation time of the mixture of step b) may depend on the process (hot or cold) used. For instance, in case step b) is conducted at lower temperatures (approx. at room temperature or lower), the incubation time may increase. According to another preferred embodiment of the present invention step b) is conducted for 1 minute to 7 days, preferably for 2 minutes to 5 days, more preferably for 5 minutes to 24 hours, more preferably for 10 minutes to 18 hours, more preferably for 20 minutes to 12 hours, more preferably for 30 minutes to 6 hours, more preferably for 1 to 3 hours.

[0030] According to another preferred embodiment of the present invention the mixture is cooled after step b) to 4°C to 10°C, preferably to 4°C to 8°C.

[0031] According to another preferred embodiment of the present invention the mixture of step b) is cooled for 1 to 72 hours, preferably for 5 to 48 hours, preferably for 10 to 30 hours.

[0032] According to another preferred embodiment of the present invention the solid particles are removed from the mixture of step b) by filtering, straining, sieving or combinations thereof. Preferably, the precipitated solid particles can be removed from the reaction mixture of step b) as long as the mixture is liquid. Preferably, the mixture of step b) can be liquefied by heating. The formed solid particles generated in step b) may have a higher melting point than the other constituents in the mixture. According to a further preferred embodiment of the present invention step c) is conducted at a temperature ranging from 30°C to 100°C, preferably from 40°C to 80°C. Consequently, the solid particles can then be separated from the liquid mixture in step c).

[0033] Alternatively, the solid particles can be removed from the mixture of step b) at least after 15 minutes, preferably at least after 10 minutes, preferably at least after 5 minutes of incubating the composition of step a) with the alkaline composition or after step b) when conducted at a temperature as defined herein. After the solid particles are removed, the obtained composition may be essentially free of short-chain free fatty acids.

[0034] According to another preferred embodiment of the present invention one or more additives is added to the mixture selected from the group consisting of a pigment, an adjuvant, a fragrance, and combinations thereof. Preferably, the adjuvant can be selected from the group consisting of plasticizers, lather enhancers, binders, moisturizers, and fillers.EXAMPLESExample 1:

[0035] 50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1 g NaOH with 41.9 g H 2 O. No polymeric guanidine was added to the composition.

[0036] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. No insoluble products were detected. The mixture was characterized by a very foul odor.Example 2:

[0037] 50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9g of a 3% solution of AKACID, oligo-(2-(ethoxy)ethoxyethylguanidinium chloride) and poly (hexamethyl-endiamine guanidinium chloride).

[0038] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.Example 3:

[0039] 50 g of clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9 g of 3% polyhexanide (PHMB).

[0040] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. T Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

Examples

example 1

[0035]50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1 g NaOH with 41.9 g H 2 O. No polymeric guanidine was added to the composition.

[0036]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. No insoluble products were detected. The mixture was characterized by a very foul odor.

example 2

[0037]50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9g of a 3% solution of AKACID, oligo-(2-(ethoxy)ethoxyethylguanidinium chloride) and poly (hexamethyl-endiamine guanidinium chloride).

[0038]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

example 3

[0039]50 g of clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9 g of 3% polyhexanide (PHMB).

[0040]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. T Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

FIELD OF THE INVENTION

[0001] The present invention relates to the field of fatty acid salts and the production thereof.BACKGROUND ART

[0002] Fatty acid salts (soaps) are a widely used as anionic surfactants. The applications include the use in washing products, cosmetics as well as surface and toilet cleaners for household and personal cleaning. The process of producing fatty acid salts has been known since antiquity, when lye was leached from the ashes of a wood fire. Industrially, molten tallow is nowadays treated with an excess of alkali in large vats. The mixture is heated and after hydrolysis is complete, the fatty acid salts are precipitated by the addition of an inorganic salt, filtered, and washed by successive solution in water.

[0003] The sensory and chemical characteristics of fatty acid salts depends on the manufacturing process, and the chemical composition of the materials used. In particular, fatty acids play key roles in the performance and the quality of the fatty acid salt compositions, consumer preferences, and costs. It is known in the art that fatty acids and fatty acid-containing compositions often exhibit reactions like autoxidation or hydrolysis when exposed to air, light, moisture, or bacterial action leading to smelly or bad-tasting products. These effects relate to the presence of free fatty acids and in particular, malodorous short-chain fatty acids as reaction products. As consequence, short-chain fatty acids are released and unpleasant odor in the product develops. Additionally, short-chain fatty acids formed in fatty acid salts serve as catalysts themselves, further accelerating the reaction. Thus, the presence of short-chain fatty acids - a minor component of most fatty acid salt compositions - has a significant influence on the overall quality and sensory characteristics, and in turn, consumer preference or acceptance of fatty acid salt compositions such as e.g., soaps.

[0004] Butyric acid, in particular, has a strong, pungent odor that is often described as resembling rotten eggs or vomit. When present in soaps, it can contribute to an unpleasant smell that many people find off-putting. To address this issue, soap manufacturers take steps to minimize the presence of butyric acid in their products. This can involve using different oils or fats in the soap-making process, as well as employing specific techniques to reduce the formation or retention of these acids. However, all know methods are labor intensive and involve complex apparatuses.

[0005] It is an object of the present invention to provide a fatty acid salt composition which is free of malodorous reaction products like butyric acid.SUMMARY OF THE INVENTION

[0006] Thus, the present invention relates to a method for producing a composition comprising fatty acid salts, preferably salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid, comprising the steps of: a) providing a composition comprising at least one short-chain fatty acid and / or an ester thereof, and at least one medium-chain fatty acid and / or an ester thereof, and / or at least one long-chain fatty acid and / or an ester thereof, b) incubating the composition of step a) with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide thereby forming solid particles comprising said at least one polymeric guanidine and said at least one short-chain fatty acid and c) removing the solid particles from the mixture of step b) .

[0007] It turned surprisingly out that polymeric guanidine can be used to remove efficiently short-chain fatty acids from a composition comprising fatty acids of various lengths in a simple way resulting in a product which is essentially free from unpleasant odors caused by these short-chain fatty acids. Malodorous short-chain fatty acids and / or an ester thereof can be removed by incubating a composition comprising fatty acids with the alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide. Surprisingly, it turned out that the polymeric guanidine binds short-fatty fatty acids and / or an ester thereof when the alkaline composition is added to the composition of step a), forming polymeric particles which are insoluble when heated to a temperature at which salts of fatty acids, in particular salts of medium- and long-chain fatty acids, typically melt. The formed solid particles comprise said at least one polymeric guanidine and said at least one short-chain fatty acid. The solid particles are then removed from the reaction mixture of step b), wherein salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid remain in the obtained composition. The present invention therefore provides a facile method to produce fragrant and qualitative compounds comprising fatty acid salts.

[0008] The method of the present invention can also be used for removing short-chain fatty acids and / or salts of short-chain fatty acids from a composition comprising fatty acids of various lengths and / or esters and / or salts thereof. Such a method comprises the step of incubating a composition comprising salts of fatty acids with at least one polymeric guanidine thereby forming solid particles comprising said at least one polymeric guanidine and short-chain fatty acids comprised in said composition. The solid particles formed are removed from the mixture with known methods. If the composition comprising fatty acid salts is highly viscous or even solid, the composition may be heated to decrease its viscosity or even to melt it allowing the removal of the solid particles formed by the polymeric guanidine and the at least one short-chain fatty acids.

[0009] Another aspect of the present invention relates to a composition obtainable by the method as defined herein.

[0010] Yet another aspect of the present invention relates to the use of the composition as defined herein as a soap, detergent or tenside.

[0011] It further turned out that the composition according to the present invention is particularly useful in the area of cleaning agents, fabric conditioners, laundry additives or cosmetics. In domestic settings, the composition of the present invention can be used as soap for washing, bathing, and other types of housekeeping. In industrial settings, it can be used as thickener, component of lubricants, and precursor to catalysts. Since the composition used according to the invention decrease the surface tension of liquids, it also particularly function as emulsifier, wetting agent, detergent, foaming agent, or dispersant.DESCRIPTION OF PREFERRED EMBODIMENTS

[0012] The term "fatty acid", as used herein, refers to a carboxylic acid with an aliphatic chain.

[0013] "Short-chain fatty acids", as used herein, are fatty acids with aliphatic tails of six or fewer carbon atoms. According to a preferred embodiment of the present invention the at least one short-chain fatty acid has a chain length of 3 to 6 carbon atoms, preferably 3 or 4 carbon atoms. Preferably, the short-chain fatty acid is butyric acid.

[0014] The term "medium-chain fatty acids", as used herein, refers to fatty acids with aliphatic tails having a chain length of 6 to 12 carbon atoms.

[0015] "Long-chain fatty acids", as used herein, include fatty acids with aliphatic tails having a chain length of 13 to 22 carbon atoms.

[0016] The "composition comprising salts of at least one medium-chain fatty acid and / or at least one long-chain fatty acid" comprises at least 50 wt % to 99 wt %, preferably 55 wt% to 95 wt%, preferably 60 wt% to 90 wt%, preferably 65 wt% to 85 wt% of the salts of the at least one medium-chain fatty acid and / or the at least one long-chain fatty acid compared to the total weight of the composition. The composition produced by the method of the present invention is essentially free from short-chain fatty acids. In this context, "essentially free", means that the composition comprises less than 5 wt%, preferably less than 4 wt%, more preferably less than 3 wt%, more preferably less than 2 wt%, more preferably less than 1 wt%, more preferably less than 0.5 wt%, more preferably less than 0.2 wt%, more preferably less than 0.1 wt%, in particular 0 wt% short-chain fatty acids. Said composition can be obtained by the method according to the present invention.

[0017] According to another preferred embodiment of the present invention the composition of step a) comprises saturated and / or unsaturated fatty acids. As used herein, the term "saturated fatty acids" refers to fatty acids having no C=C double bonds and are defined by the formula CH 3 (CH 2 )nCOOH, wherein n can be any integer. "Unsaturated fatty acids", as used herein, mean fatty acids having one or more C=C double bonds. The C=C double bonds can give either cis or trans isomers. The unsaturated fatty acid, as used herein, are presented by the formula CH 3 (CH 2 )nCH=CH(CH 2 )nCOOH, wherein n can be any integer.

[0018] The composition of step a), in particular the fatty acids and / or salts thereof, can be of animal and / or vegetable origin. According to another preferred embodiment of the present invention the composition of step a) is at least one animal and / or vegetable fat and / or oil. Preferably, the least one animal fat can be part of milk, butter, tallow or lard. The at least one vegetable fat or oil can be coconut oil, grapeseed oil, hemp seed oil, olive oil, palm oil, rose hip oil, canola oil, cocoa butter and shea butter. The composition of step a) can be stirred and / or heated before proceeding with step b) to ensure a homogenous mixture and to avoid the occurrence of clumps.

[0019] According to the present invention the composition of step a) can be incubated with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide. According to another preferred embodiment of the present invention the composition of step a) and the alkaline composition are mixed in a weight ratio of between 10:1 to 1:1, preferably between 5:1 to 1:1, preferably between 2:1 to 1:1, preferably between 1.5:1 to 1:1. Surprisingly, it turned out that the solid particles can be efficiently formed by mixing the composition of step a) and the alkaline composition at a defined ratio. Preferably, the alkaline composition can be prepared separately before incubating with the composition of step a).

[0020] Polymeric guanidine is a cationic polymer which is usually used as antiseptic for e.g., textiles or room disinfectant in hospital settings. Polymeric guanidine is generally characterized by high-efficiency, good stability, high and thermal decomposition temperature and represents a non-toxic and non-irritating material. The polymer has become a major research topic in the field of sterilization in recent years. Due to its high activity, the guanidine group is positively charged and easily adsorbed by various types of bacteria and viruses that are usually negatively charged, thus resisting the functions of bacteria and viruses. The prior art also describes drugs which contain the polymeric guanidine derivatives as active ingredients, having an antimicrobial effect. Hence, the polymer can also be used in human medicine as well as in veterinary medicine to combat infections. Biocidal polymeric guanidine salts are known in the art. Chlorides of these polymers are prepared by reacting diamine, e.g., hexamethylene diamine or triethylene glycol diamine, with guanidine hydrochloride. This forms a cationic polymer (polyguanidinium cation) with chloride as counterion. For instance, this compound is known to possess pronounced biocidal properties. Other salts of polymeric guanidine can be prepared by using another salts of guanidine instead of hydrochloride. The salt of the at least one polymeric guanidine can be prepared with dihydrogen phosphate, carbonate, nitrate, dehydroacetate citrate, or preferably hydrochloride as counterion.

[0021] According to a preferred embodiment of the present invention the at least one polymeric guanidine is selected from the group consisting of polyhexamethylene guanidine (PHMG), poly(2-(2-ethoxy)-ethoxyethyl)-guanidine, polyhexamethylene biguanide (PHMB), polytriethylene glycol guanidine, polyethylene glycol guanidine, polyoxypropylene guanidine, polyaminopropyl biguanide (PAPB), methacryloyl guanidine, salts thereof and mixtures thereof.

[0022] It has been surprisingly turned out that polymeric guanidine can be used to remove short-chain fatty acids in fatty acid salt production. In particular, the counterion of the at least one polymeric guanidine (i.e., hydrochloride) can be exchanged with cations of the fatty acid salt, producing a salt as intermediate product. The cationic polymeric guanidine specifically binds short-chain fatty acids of the fatty acid salt and / or an ester thereof, forming insoluble particles, which can be removed according to the invention. Another advantage of the present invention is that the solid particles can be formed within several minutes and can be easily identified by eye.

[0023] According to another preferred embodiment of the present invention the alkaline mixture of step b) comprises 0.5 to 20 wt %, preferably 1 to 10 wt %, preferably 2 to 5 wt %, of the at least one polymeric guanidine.

[0024] According to another preferred embodiment of the present invention at least one alkali salt is added to the mixture of step b). When at least one alkali salt is added, the solubility of the mixture is reduced and it precipitates. This process of flocculation is also called "salting out". The precipitated mixture can be separated from (liquid) impurities such as excess lye, glycerin, and water. According to another preferred embodiment of the present invention the at least one alkali salt is selected from the group consisting of sodium chloride, potassium chloride and mixtures thereof.

[0025] To produce the composition according to the invention, fatty acids and / or esters thereof in fats, oils, used as feedstock are converted in the presence of least one alkali hydroxide to form fatty acid salts. According to another preferred embodiment of the present invention the at least one alkali hydroxide is selected from the group consisting of sodium hydroxide, potassium hydroxide and mixtures thereof.

[0026] Fatty acid salts can be produced by two main processes known in the art, the cold process, and the hot process.

[0027] The hot process involves combining a lye mixture with oils and / or fats. The mixture is heated to speed up the saponification process, which means the final products can be further processed within one day and used right away. However, the obtained composition can be stored, giving it the opportunity for the water to evaporate to create a harder, longer-lasting product. The hot process is commonly used for mass-production. Unlike the cold process, the essential oils, fragrances, and other additives are added after the chemical reaction is finished, which helps to preserve the benefits of the natural ingredients and the scents to last longer.

[0028] The cold process uses the heat generated from the combination of the fatty acids in the melted oils and fats with an alkaline solution to facilitate the saponification process, which takes several hours to complete, and weeks to cure the finished product. The mixture can be slightly warmed to achieve a homogenous mixture. One of the main benefits of the cold process is having complete control over the ingredients, having no added detergents which can e.g., strip off the skin's natural oils. Since cold process does not rely on heat, it is easier to maintain the efficacy of the natural properties of active ingredients like natural and essential oils. The mixture of step b) can be incubated at a temperature ranging from 5°C to 100°C, allowing the use of a cold or a hot process to produce the composition according to the present invention. According to a preferred embodiment of the present invention step b) is conducted at a temperature ranging from 5°C to 100°C, preferably from 10°C to 90°C, more preferably from 20°C to 80°C, more preferably from 30°C to 70°C. This is particularly advantageous, since the properties of the final product can be individually adapted, depending on the process used.

[0029] Thus, the incubation time of the mixture of step b) may depend on the process (hot or cold) used. For instance, in case step b) is conducted at lower temperatures (approx. at room temperature or lower), the incubation time may increase. According to another preferred embodiment of the present invention step b) is conducted for 1 minute to 7 days, preferably for 2 minutes to 5 days, more preferably for 5 minutes to 24 hours, more preferably for 10 minutes to 18 hours, more preferably for 20 minutes to 12 hours, more preferably for 30 minutes to 6 hours, more preferably for 1 to 3 hours.

[0030] According to another preferred embodiment of the present invention the mixture is cooled after step b) to 4°C to 10°C, preferably to 4°C to 8°C.

[0031] According to another preferred embodiment of the present invention the mixture of step b) is cooled for 1 to 72 hours, preferably for 5 to 48 hours, preferably for 10 to 30 hours.

[0032] According to another preferred embodiment of the present invention the solid particles are removed from the mixture of step b) by filtering, straining, sieving or combinations thereof. Preferably, the precipitated solid particles can be removed from the reaction mixture of step b) as long as the mixture is liquid. Preferably, the mixture of step b) can be liquefied by heating. The formed solid particles generated in step b) may have a higher melting point than the other constituents in the mixture. According to a further preferred embodiment of the present invention step c) is conducted at a temperature ranging from 30°C to 100°C, preferably from 40°C to 80°C. Consequently, the solid particles can then be separated from the liquid mixture in step c).

[0033] Alternatively, the solid particles can be removed from the mixture of step b) at least after 15 minutes, preferably at least after 10 minutes, preferably at least after 5 minutes of incubating the composition of step a) with the alkaline composition or after step b) when conducted at a temperature as defined herein. After the solid particles are removed, the obtained composition may be essentially free of short-chain free fatty acids.

[0034] According to another preferred embodiment of the present invention one or more additives is added to the mixture selected from the group consisting of a pigment, an adjuvant, a fragrance, and combinations thereof. Preferably, the adjuvant can be selected from the group consisting of plasticizers, lather enhancers, binders, moisturizers, and fillers.EXAMPLESExample 1:

[0035] 50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1 g NaOH with 41.9 g H 2 O. No polymeric guanidine was added to the composition.

[0036] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. No insoluble products were detected. The mixture was characterized by a very foul odor.Example 2:

[0037] 50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9g of a 3% solution of AKACID, oligo-(2-(ethoxy)ethoxyethylguanidinium chloride) and poly (hexamethyl-endiamine guanidinium chloride).

[0038] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.Example 3:

[0039] 50 g of clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9 g of 3% polyhexanide (PHMB).

[0040] Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. T Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

Examples

example 1

[0035]50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1 g NaOH with 41.9 g H 2 O. No polymeric guanidine was added to the composition.

[0036]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. No insoluble products were detected. The mixture was characterized by a very foul odor.

example 2

[0037]50 g clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9g of a 3% solution of AKACID, oligo-(2-(ethoxy)ethoxyethylguanidinium chloride) and poly (hexamethyl-endiamine guanidinium chloride).

[0038]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

example 3

[0039]50 g of clarified butter comprising about 1.5-2.5 g butyric acid was melted at 60°C in a beaker. An alkaline composition was prepared by dissolving 8.1g NaOH with 41.9 g of 3% polyhexanide (PHMB).

[0040]Reagents were mixed and poured into a silicone container. The mixture was cooled for 24h at 4°C. T Then the mixture was heated to 60°C and thus liquefied. An insoluble polymer lump could be filtered out. This lump had a strong odor. The mixture without the solid polymer lump was filled back into a mold and cooled. The obtained product was odorless without traces of butyric acid.

Claims

1. A method for producing a composition comprising fatty acid salts, comprising the steps of: a) providing a composition comprising - at least one short-chain fatty acid and / or an ester thereof, and - at least one medium-chain fatty acid and / or an ester thereof, and / or - at least one long-chain fatty acid and / or an ester thereof, b) incubating the composition of step a) with an alkaline composition comprising at least one polymeric guanidine and at least one alkali hydroxide thereby forming solid particles comprising said at least one polymeric guanidine and said at least one short-chain fatty acid and c) removing the solid particles from the mixture of step b) .

2. The method according to claim 1, wherein the at least one short-chain fatty acid has a chain length of 3 to 6 carbon atoms, preferably 3 or 4 carbon atoms.

3. The method according to claim 1 or 2, wherein the composition of step a) and the alkaline composition are mixed in a weight ratio of between 10:1 to 1:1, preferably between 5:1 to 1:1, preferably between 2:1 to 1:1, preferably between 1.5:1 to 1:1.

4. The method according to any one of claims 1 to 3, wherein the at least one polymeric guanidine is selected from the group consisting of polyhexamethylene guanidine (PHMG), poly(2-(2-ethoxy)-ethoxyethyl)-guanidine, polyhexamethylene biguanide (PHMB), polytriethylene glycol guanidine, polyethylene glycol guanidine, polyoxypropylene guanidine, polyaminopropyl biguanide (PAPB), methacryloyl guanidine, salts thereof and mixtures thereof.

5. The method according to any one of claims 1 to 4, wherein the alkaline mixture of step b) comprises 0.5 to 20 wt %, preferably 1 to 10 wt %, preferably 2 to 5 wt %, of the at least one polymeric guanidine.

6. The method according to any one of claims 1 to 5, wherein at least one alkali salt is added to the mixture of step b).

7. The method according to claim 6, wherein the at least one alkali salt is selected from the group consisting of sodium chloride, potassium chloride and mixtures thereof.

8. The method according to any one of claims 1 to 7, wherein the at least one alkali hydroxide is selected from the group consisting of sodium hydroxide, potassium hydroxide and mixtures thereof.

9. The method according to any one of claims 1 to 8, wherein the solid particles are removed from the mixture of step b) by filtering, straining, sieving or combinations thereof.

10. The method according to any one of claims 1 to 9, wherein step b) is conducted at a temperature ranging from 5°C to 100°C, preferably from 10°C to 90°C, more preferably from 20°C to 80°C, more preferably from 30°C to 70°C, and / or step c) is conducted at a temperature ranging from 30°C to 100°C, preferably from 40°C to 80°C.

11. The method according to any one of claims 1 to 10, wherein step b) is conducted for 1 minute to 7 days, preferably for 2 minutes to 5 days, more preferably for 5 minutes to 24 hours, more preferably for 10 minutes to 18 hours, more preferably for 20 minutes to 12 hours, more preferably for 30 minutes to 6 hours, more preferably for 1 to 3 hours.

12. The method according to any one of claims 1 to 11, wherein the mixture is cooled after step b) to 4°C to 10°C, preferably to 4°C to 8°C.

13. The method according to claim 12, wherein the mixture of step b) is cooled for 1 to 72 hours, preferably for 5 to 48 hours, preferably for 10 to 30 hours.

14. A composition obtainable by the method according to any one of claims 1 to 13.

15. Use of the composition according to claim 14 as a soap, detergent or tenside.

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