A dispersion comprising heat-treated xanthan

Abstract

The present invention relates to a dispersion comprising at least one cosmetically acceptable oil and heat-treated xanthan, wherein the heat-treated xanthan is dispersed in the cosmetically acceptable oil, and wherein heat-treated means that the xanthan has been in contact with water, the water having a pH value of 1 or higher and 9 or less and, after the water has been removed, the xanthan has been kept at a temperature of 110 °C to 150 °C for 0.5 to 12 hours. Furthermore, the present invention relates to a process for making the dispersion and to a cosmetic composition comprising water, the dispersion and optionally one or more further cosmetically acceptable ingredients.

Description

[0001] A Dispersion Comprising Heat-Treated Xanthan

[0002] The present invention relates to a dispersion comprising at least one cosmetically acceptable oil and heat-treated xanthan, wherein the heat-treated xanthan is dispersed in the cosmetically acceptable oil, and wherein heat-treated means that the xanthan has been in contact with water, the water having a pH value of 1 or higher and 9 or less and, after the water has been removed, the xanthan has been kept at a temperature of 110°C to 150 °C for 0.5 to 12 hours. Furthermore, the present invention relates to a process for making the dispersion and to a cosmetic composition comprising water, the dispersion and optionally one or more further cosmetically acceptable ingredients.

[0003] Cosmetic compositions comprising water, e. g. shower gels or shampoos or lotions, need to have an appropriate viscosity. Therefore, such compositions frequently comprise substances for increasing their viscosity. These substances are called thickeners. Although many thickeners are known in the state of the art there is an ongoing need to provide further thickeners with advantageous properties. The same is true for pharmaceutical compositions, paints and further aqueous compositions in various technical fields.

[0004] US 8,545,828 B1 discloses heat-treated xanthan gum. An aqueous solution of this heat-treated xanthan gum has a higher viscosity than an aqueous solution of xanthan gum that has not been heat-treated. Cosmetic compositions comprising heat-treated xanthan gum are disclosed. Heat-treatment means applying a temperature of 60 °C or more (US '828, claim 2). Temperatures of 104 °C and of 110 °C are used in the examples of US '828. It is disclosed that an acidic pH of 2 to 4 is more suitable for carrying out the heat-treatment than other pH values.

[0005] EP 0 128661 A1 discloses a dispersion of a polysaccharide in oil in the presence of surfactants and / or stabilizers. The dispersion is made by dispersing an aqueous solution of the polysaccharide in oil followed by drying the resulting emulsion. The oil generally comprises volatile and non-volatile components such that the drying can be azeotroping. Before the drying step, ammonia or other alkali is added to avoid crosslinking reactions (paragraph bridging pages 8 and 9). The initial polysaccharide solution has a low polysaccharide concentration because concentrated solutions have high viscosities and are difficult to handle. This is disadvantageous because high amounts of water have to be removed in the drying step, which leads to high energy consumption. Another disadvantage of the dispersion disclosed is that it must be assumed that they contain residual volatile oil which is undesired, e. g. for cosmetic applications. EP '661 discloses the use of the dispersions disclosed for enhanced oil recovery (abstract). Example 1 of EP '661 discloses a process for making a dispersion of xanthan in oil. During this process temperatures of up to 95 °C are applied for distilling-off a volatile oil. The aqueous xanthan gum used has been adjusted to a pH of 10 with ammonia. As explained in the paragraph bridging pages 8 and 9 of EP '661 this avoids crosslinking. The xanthan gum solution used as starting material has a concentration of 7 % by weight. EP '661 discloses a dry size of polysaccharide particles of 2 to 10 micrometers (claim 8).

[0006] EP 0 137 538 discloses a polysaccharide-containing water in oil emulsion. The use of this emulsion for thickening aqueous systems is disclosed. These aqueous systems can be used in enhanced oil recovery (EP '538, claim 16). The polysaccharide can be xanthan (EP '538, example 1). The water content of these emulsions is 5 % by weight or higher (EP '538, claim 1).

[0007] A first subject of the present invention is a dispersion comprising at least one cosmetically acceptable oil and heat-treated xanthan, wherein the heat-treated xanthan is dispersed in the cosmetically acceptable oil, and wherein heat-treated means that the xanthan has been in contact with water, the water having a pH value of 1 or higher and 9 or less, preferably 3 or higher and 8.5 or less, more preferably 5 or higher and 8 or less, more preferably 6 or higher and 7.7 or less, and, after the water has been removed, the xanthan has been kept at a temperature of 110 °C to 150°C, preferably at 110 °C to 130 °C, more preferably 115 °C to 125 °C, for 0.5 to 12 hours, preferably 1 to 10 hours, more preferably 1.5 to 8 hours, more preferably 1.5 to 2.5 hours.

[0008] In the context of the present invention, the term “cosmetically acceptable oil” or, synonymously, “emollient” is understood to mean substances that make the skin soft and supple, especially by supplying the skin with lipids or reducing evaporation or increasing the moisture content of the skin. Suitable emollients are substances from the group of the oils, fats, waxes, hydrocarbons and / or organosilicon compounds that are liquid at room temperature or have a melting point < 70°C.

[0009] Emollients present may be oils, fats and / or waxes, for example from the group formed by esters, wax esters, waxes, triglycerides or partial glycerides, natural vegetable oils or fats, hydrocarbons, organosilicon compounds, Guerbet alcohols, mono- / dialkylethers, mono- / dialkyl carbonates, and mixtures thereof. Exemplary esters that may be present include, but are not limited to, those of linear fatty acids with linear or branched fatty alcohols, esters of linear fatty alcohols with linear or branched carboxylic acids, esters of alkyl hydroxycarboxylic acids with linear or branched fatty alcohols, esters of linear or branched fatty acids with polyhydric alcohols such as diols or trimer triol, wax esters, triglycerides or partial glycerides (called mono- / di- / triglyceride esters), esters of fatty alcohols and / or Guerbet alcohols with aromatic carboxylic acids, esters of dicarboxylic acids with linear or branched alcohols, natural vegetable oils or fats and mixtures thereof.

[0010] Suitable examples from the group of esters of linear C6-C22 fatty acids with linear or branched C6-C22 fatty alcohols or esters of branched C6-C22 carboxylic acids with linear or branched C6-C22 fatty alcohols are myristyl myristate (commercially available as Cetiol® MM), myristyl isostearate, myristyl oleate, myristyl erucate, cetyl isostearate, cetyl oleate, cetyl erucate, stearyl myristate, stearyl isostearate, stearyl oleate, stearyl erucate, isostearyl myristate, isostearyl palmitate, isostearyl stearate, isostearyl isostearate, isostearyl oleate, isopropyl myristate, isopropyl palmitate, oleyl myristate, oleyl palmitate, oleyl stearate, oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate (commercially available as Cetiol® J 600), behenyl oleate, behenyl erucate, erucyl myristate, erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate and erucyl erucate, ethylhexyl stearate (commercially available as Cetiol® 868), hexyl laurate (commercially available as Cetiol® A), coco-caprylate (commercially available as Cetiol® C5), coco-caprylate / caprate (commercially available as Cetiol® LC, Cetiol® C 5C), propylheptyl caprylate (commercially available as Cetiol® Sensoft), cetearyl isononanoate (commercially available as Cetiol® SN), decyl oleate (commercially available as Cetiol® V), cetearyl ethylhexanoate.

[0011] Similarly suitable are esters of alkyl hydroxy carboxylic acids with linear or branched C6-C22 fatty alcohols, preferably esters of lactic acid such as lauryl lactate.

[0012] Also suitable are esters of dicarboxylic acids and linear or branched alcohols, preferably esters of malic acid, adipic acid and / or sebacic acid, such as dibutyl adipate, dioctyl malate and / or diisopropyl sebacate.

[0013] Also suitable are esters of linear and / or branched fatty acids with polyhydric alcohols (such as propylene glycol, dimer diol or trimer triol), such as propylene glycol dicaprylate / dicaprate (commercially available as Myritol® PGDC), triglycerides based on C6-C10 fatty acids, liquid monoglycerides, diglycerides or mono- / di- / triglyceride mixtures based on C6-C18 fatty acids (commercially available as Myritol® 331 , Myritol® 312, Myritol® 318), esters of C6-C22 fatty alcohols and / or Guerbet alcohols with aromatic carboxylic acids, especially benzoic acid, esters of benzoic acid with linear and / or branched C6-C22 alcohols (e.g. commercially available as Finsolv® TN, Cetiol® AB). Also suitable are hydrogenated glycerides, for example hydrogenated vegetable glycerides (commercially available as Cutina® HVG).

[0014] Of good suitability as natural, especially vegetable, fats and oils are groundnut oil, soybean oil, jojoba oil, rapeseed oil, hemp seed oil, avocado oil, argan oil, castor oil, sunflower oil, palm oil, palm kernel oil, linseed oil, almond oil, wheat germ oil, macadamia nut oil, olive oil, sesame oil, cocoa butter and shea butter, for example commercially available as Cegesoft® PFO, Cegesoft® PS 6, Cegesoft® SBE, Cegesoft® SH, Cegesoft® VP or Cetiol® SB 45.

[0015] Also usable as emollient are, for example, natural vegetable waxes such as fruit waxes (for example orange waxes) and animal waxes such as wool wax.

[0016] Also suitable as emollient are C12-C15 fatty alcohols that are usually obtained from natural fats, oils and waxes, such as lauryl alcohol, myristyl alcohol or 1 -pentadecanol.

[0017] Further suitable emollients are organosilicon compounds, which are frequently referred to simply as silicones. They may take the form of cyclic, branched or linear silicones. Silicones are high molecular weight synthetic polymeric compounds in which silicon atoms are joined via oxygen atoms in a chain-like and / or grid-like manner and the remaining valences of silicon are satisfied by hydrocarbon radicals (usually methyl, more rarely ethyl, propyl, phenyl groups etc.). Systematically, the silicones are referred to as polyorganosiloxanes.

[0018] Advantageous polyorganosiloxanes are, for example, the methyl-substituted polyorganosiloxanes. They are also referred to as Polydimethylsiloxane (PDMS) or Dimethicone (INCI). Dimethicones come in various chain lengths and with various molecular weights. They are available, for example, under the Abil® 350 trade name from Evonik or Xiameter PMX-200 Silicone Fluid trade name from Dow Chemicals.

[0019] Also advantageous are phenylmethylpolysiloxane (INCI: Phenyl Dimethicone, Phenyl Trimethicone), cyclic silicones (e.g. decamethylcyclopentasiloxane or dodecamethylcyclopentasiloxane), which are also referred to in accordance with INCI as cyclomethicone, aminomodified silicones (INCI: Amodimethicone) and silicone waxes, e.g. polysiloxane-polyalkylene copolymers (INCI: Stearyl Dimethicone and Cetyl Dimethicone) and dialkoxydimethylpolysiloxanes (Stearoxy Dimethicone and Behenoxy Stearyl Dimethicone), which are available as various Abil wax grades from Evonik. Silicones which are particularly preferred are dimethicone, amodimethicone and cyclomethicone. Further suitable emollients are mono- and / or dialkyl carbonates of linear or branched C6-C22 fatty alcohols, such as dicaprylyl carbonate (commercially available as Cetiol® CC) or dipropylheptyl carbonate (commercially available as Cetiol® 4AII), Guerbet carbonates based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, linear or branched, symmetrical or asymmetrical dialkyl ethers having 6 to 22 carbon atoms per alkyl group, for example dicaprylyl ether (commercially available as Cetiol® OE).

[0020] Further suitable emollients are hydrocarbons such as mineral oils, paraffinum liquidum, undecane / tridecane (commercially available as Cetiol® Ultimate), hydrogenated polyisobutene (Luvitol® Lite), substituted cyclohexanes, isoparaffins or paraffins as well as C9- C12 alkanes.

[0021] Suitable Guerbet alcohols are those based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms (commercially available as Eutanol® G, Eutanol® G 16).

[0022] Particularly preferred emollients in the dispersions of the invention include, but are not limited to, symmetrical or asymmetrical dialkyl ethers having 6 to 22 carbon atoms per alkyl group, for example dicaprylyl ether, hydrogenated glycerides, for example hydrogenated vegetable glycerides, mono glycerides, such as glyceryl oleate, liquid mono- / di- / triglyceride mixtures based on C6-C18 fatty acids, and esters of linear C6-C22 fatty acids with isopropanol or linear or branched C6-C22 fatty alcohols, for example isopropyl palmitate, ethylhexyl stearate, coco- caprylate / caprate, and combinations thereof.

[0023] Particularly preferred emollients in the dispersions of the invention include, but are not limited to, coco-glycerides and caprylic / capric triglycerides.

[0024] Particularly preferred emollients in the dispersions of the invention are biobased and have a naturality index according to ISO 16128 of at least 3.8.

[0025] In one embodiment the dispersion according to the present invention further comprises water.

[0026] In one embodiment the dispersion further comprises at least one emulsifier. In the context of the present invention, the term “emulsifier” is understood to mean a substance that stabilizes an emulsion by reducing the oil-water interface tension and that has a molar mass of not more than 1000 g / mol. In one embodiment of the present invention the at least one emulsifier is an oil-soluble W / O emulsifier. The at least one emulsifier can have an HLB-value of 3 to 8. The at least one emulsifier can be non-ionic. Preferably it is miscible with the at least one cosmetically acceptable oil. Preferably it is biodegradable.

[0027] The emulsifier according to the present invention can be a polyethylene glycol-derivative of a fatty alcohol, it can be a polypropylene glycol-derivative of a fatty alcohol, it can be a fatty acid ester of a polyol, e. g. sorbitol, glycerol, polyglycerol, a sugar like sucrose or pentaerythritol, polyethylene glycol, polypropylene glycol, a copolymer of ethylene glycol and propylene glycol, it can be an alkyl polyglycoside.

[0028] The emulsifier according to the present invention can have a hydrophobic chain having 12 to 30 C-atoms. This hydrophobic chain can be a fatty acid moiety or a fatty alcohol moiety, it can be a oligomeric fatty acid moiety, e. g. resulting from a cocondensation of hydroxyalkyl compounds like hydroxy stearic acid.

[0029] The emulsifier according to the present invention can be selected from the group consisting of PEG-30 Dipolyhydroxystearate, Polyglyceryl-2 Dipolyhydroxystearate, Polyglyceryl-3 Caprate, Polyglyceryl-3 Diisostearate, Polyglyceryl-3 Distearate, PEG-30 Dipolyhydroxystearate, Polyglyceryl-3 Polyricinoleate, Sorbitan-monooleate, Sorbitan-monostearate, Sorbitan- trioleate, and Sorbitan-tristearate.

[0030] In one embodiment the dispersion further comprises at least one stabilizer. In the context of the present invention, the term “stabilizer” is understood to mean a polymer having an average molar mass Mw of more than 1000 g / mol, preferably more than 10000 g / mol that stabilizes an emulsion.

[0031] The at least one stabilizer according to the present invention can be a hydrophobic polymer that has polar groups, preferably non-ionic polar groups.

[0032] The at least one stabilizer according to the present invention can be selected from the group consisting of a copolymer of stearylmethacrylate, methylmethacrylate and methacrylic acid, a copolymer of stearylmethacrylate and methacrylic acid and a block copolymer in which a central poly-1 , 2-propylene glycol group is flanked by two polyethylene glycol groups.

[0033] The at least one stabilizer according to the present invention can be a polymer having an average molar mass Mw of more than 1000 g / mol, preferably more than 10000 g / mol that stabilizes an emulsion. The stabilizer preferentially is an amphiphilic compound. It contains a majority of groups which impart affinity to the emollient used and a minority of groups which impart affinity to water or alcohols, based on weight. The stabilizer preferably has a watersolubility of less than 5 w.-% at room temperature. The stabilizer may impart an additional steric stabilization to the dispersion according to the present invention.

[0034] In one embodiment, the stabilizer is preferentially soluble in the emollient or forms stable colloidal dispersions in the emollient. Examples of such stabilizers are SMA / MAA copolymers, PEG / PPO block copolymers, and the like. In another embodiment, the stabilizer is composed of emollient-dispersible particles with an affinity to polar surfaces. Such particles may be inorganic or organic. Examples of inorganic particles are bentonites and hectorites which have been loaded with hydrophobic components, an example being Stearylalkonium Hectorite. Examples of particulate organic materials are compounds, which are partly insoluble in the emollient used. Examples are hydrophobically modified polysaccharides, e. g. ethyl cellulose or cellulose acetate.

[0035] In one embodiment the dispersion comprises 30 to 80 % by weight, preferably 35 - 65 %, especially preferred 38 - 62% by weight, of the at least one cosmetically acceptable oil, 10 to 60 % by weight, preferably 20 - 55 % by weight, especially preferred 25 - 50% by weight of heat-treated xanthan, 1 to 25 % by weight, preferably 2 - 22 % by weight, especially preferred 3 - 15% by weight of the at least one emulsifier, and 0 to 6 % by weight, preferably 0.5 - 5 % by weight, especially preferred 1 - 4% by weight of the at least one stabilizer. The data refer to the dispersion when the majority of water optionally used in the process has been removed.

[0036] In one embodiment the dispersion is essentially free of any volatile oil, wherein a volatile oil is an aliphatic or cycloaliphatic hydrocarbon that is different from the cosmetically acceptable oil and has a boiling point of 250 °C or less, preferably 100 °C or less, and wherein free of means less than 2 % by weight, preferably less than 0.5 % by weight.

[0037] In one embodiment of the dispersion according to the present invention the average particle size of the heat-treated xanthan dso is equal to or less than 25 pm, preferably equal or less than 17 pm, especially preferred equal or less than 10 pm, wherein dso is determined by Fraunhofer diffraction measurements carried out with the dispersion.

[0038] Fraunhofer diffraction measurements carried out with the dispersion is a laser diffraction method. It is carried out as follows. A Mastersizer 3000 (obtainable from Malvern Pananalytical) with a Hydro SV unit installed is used for the measurements. A sample of the dispersion is diluted with the cosmetically acceptable oil of the dispersion. If the dispersion comprises further components apart from xanthan, cosmetically acceptable oil and water, then the concentration of these further components is kept constant during the dilution by adding corresponding amounts of these further components. Before each measurement, background acquisition measurements are done with a blank sample (comprising the cosmetically acceptable oil and the further components, if any. The pre-diluted dispersion is then added dropwise to the blank sample, without removing the measurement cell from the Mastersizer 3000, upon continuous stirring via an installed stirrer at a rate of 500 - 1000 rpm. The prediluted dispersion is added until an obscuration level of 5-15 % is reached. Data analysis is then performed with the Mastersizer 3000 software using the Fraunhofer scattering model.

[0039] Another subject of the present invention is a process for making the dispersion according to the present invention comprising

[0040] • providing the cosmetically acceptable oil,

[0041] • adding xanthan in the form of a powder to the oil, so that a xanthan-in-oil dispersion is obtained,

[0042] • adding water to the xanthan-in-oil dispersion, so that a dispersion of xanthan plus water in oil is obtained,

[0043] • optionally permitting a swelling time, wherein this swelling time preferably is 0.1 to 24 hours, preferably 1 to 24 hours,

[0044] • reducing the average particle size of the dispersion of xanthan plus water in oil by applying shearing, preferably by stirring the dispersion of xanthan plus water in oil,

[0045] • optionally permitting a further swelling time, wherein this further swelling time preferably is 0.1 to 24 hours, preferably 1 to 24 hours,

[0046] • removing at least some of the water present in the dispersion of xanthan plus water in oil,

[0047] • heat-treating the dispersion, wherein this heat-treating can partially or totally occur while removing the at least some of the water or thereafter.

[0048] In one embodiment of the process according to the present invention the amount of water added is 0.5 to 3 times, preferably 0.7 to 2.5 times, more preferably 0,8 to 2.2 times, the amount of the xanthan, wherein amount means mass.

[0049] The step of adding xanthan in the form of a powder to the oil, so that a xanthan-in-oil dispersion is obtained, is preferably done with the application of shear forces. For this, conventional dispersing equipment like stirrers, dissolver disks or rotor-stator-machines can be used. Subsequently, water is added, preferably gradually, preferably under strong agitation allowing it to diffuse to the individual hydrophilic xanthan particles and to hydrate them.

[0050] After addition of the water, the system is optionally kept for some time. An example are 0.1 - 24 h, preferably 0.2 - 16 h, even more preferably 0.3 - 8 h. A selected swelling time may be, for example, 0.5 - 2 h. Preferably, the system is agitated during that time. The time may also be distributed into various steps, for example before or after dispersing steps.

[0051] After the incorporation of all ingredients and the hydration of the xanthan particles, the resulting dispersion is preferably further processed to reduce the size of the hydrated xanthan particles by applying high shear and elongation forces to the dispersion. This process step can be carried out either in batch or in continuous mode.

[0052] The required shear and elongation forces may be employed via special stirrer set-ups or dissolver disks. Alternatively, gear rim dispersing devices may be used. The latter typically consist of toothed rims which move relative to each other at high shear rates. Colloids mills may be also employed which commonly possess a rotating truncated cone, which additionally may be toothed. The required shear and elongation forces may be also employed via a high pressure homogenizer. The latter commonly leads to elongation and turbulent shear at / after a narrow orifice.

[0053] Examples for high-shear rotor-stator devices and high-pressure dispersing units and their manufacturers are described in “Emulgiertechnik- Grundlagen, Verfahren und Anwendungen, Helmar Schubert, B. Behr’s Verlag GmbH & Co. KG, AverhoffstraBe 10, 22085 Hamburg, 1st edition, 2005, Chapters 10 to 12“.

[0054] In batch mode, high shear mixing devices can be employed. Examples are the Ultraturrax® by IKA-Werke GmbH & Co KG, Staufen, Germany or Polytron® by Kinematica AG, Malters, Switzerland or other high shear equipment. The required dispersing time is depending on the batch size, the geometry and tip speed of the rotor-stator device and the desired final particle size of the hydrated xanthan particles in the dispersion.

[0055] In continuous operation mode, the xanthan particle size reduction is carried out using an inline dispersing machine. Suitable devices are high pressure homogenizers, rotor-stator or rotorrotor dispersing machines. These types of machines are known to the expert. Because of their operational robustness and reliability, rotor-stator machines are preferred but not limited for the given task. The other methods are not excluded. Examples for rotor-stator dispersing machines are the Cavitron® CD series by CAVITRON® v. Hagen & Funke GmbH, Sprockhovel, Germany, the Supraton® S-series by Buckau-Wolf GmbH, Grevenbroich, Germany and the DISPAX® DRS by IKA-Werke GmbH & Co KG, Staufen, Germany. The given examples do not claim to be complete. The dispersion with the coarse hydrated xanthan particles is continuously fed in a first pass from a first stirred vessel to the process chamber of the dispersing machine, where the comminution of the xanthan particles takes place. Subsequently, the dispersion is collected in a second stirred vessel. Depending on the desired final particle size distribution of the hydrated xanthan, more than one pass through the dispersing machine may be required to achieve the target.

[0056] In a special embodiment, the dispersion process can also be carried out in recirculation or loop mode. In this case, the dispersion with the coarse hydrated xanthan particles is continuously fed from a stirred vessel to the dispersing machine. After the comminution in the process chamber of the dispersing machine, the dispersion is conveyed back into the same stirred vessel. Depending on the volume of dispersion and the mixing conditions in the stirred vessel as well as the flow rate through the dispersing machine, a certain recirculation time is required until the desired final particle size distribution of the hydrated xanthan is reached.

[0057] Because of the energy dissipation during the dispersion process the dispersion will heat up and it may be necessary to cool the dispersion to avoid a temperature-induced modification of the polymer.

[0058] The removing at least some of the water present in the dispersion of xanthan plus water in oil can be done by applying vacuum.

[0059] Another subject of the present invention is the use of the dispersion according to the present invention for making a cosmetic composition.

[0060] The term “cosmetic composition”, as used herein, relates to all compositions known to the person skilled in the art which are exclusively or primarily intended to be used externally on the human body or in its oral cavity for cleaning, care, protection, maintaining a good condition, perfuming, changing the appearance or for the purposes of influencing body odor. Said compositions include formulations for body care, face care, skin care, hand care and hair care as well as decorative cosmetics e. g. body milks, creams, lotions, aftershave lotions, products for eliminating body odor such as deodorants and antiperspirants, make-up removers, conditioners, and styling products. Also included are formulations typically containing surfactants, such as e. g. foam and shower baths, hair shampoos and care rinses. The cosmetic compositions of the present invention can be any of the above. In an embodiment of the present invention they are selected from shower gels, hair shampoos, foam and showers baths, skin care creams, in particular hand care creams, and body lotions. In various embodiments, the composition is a rinse off composition. This includes, without limitation, shower gels, shampoos, hair conditioners, foam baths and the like.

[0061] Another subject of the present invention is a process for making a cosmetic composition by mixing the dispersion according to the present invention with one or more further cosmetically acceptable ingredients.

[0062] The one or more further cosmetically acceptable ingredients can be any cosmetically acceptable ingredient. Several sources disclose cosmetically acceptable ingredients. E. g. the database Cosing on the homepage of the European Commission discloses cosmetic ingredients and the International Cosmetic Ingredient Dictionary and Handbook, edited by the Personal Care Products Council (PCPC) discloses cosmetic ingredients.

[0063] Surfactants

[0064] In one embodiment of the invention, the compositions comprise at least one surfactant.

[0065] Surfactants are amphiphilic substances which can dissolve organic, nonpolar substances in water. They cause, as a result of their specific molecular structure with at least one hydrophilic and a hydrophobic molecular moiety, a lowering of the surface tension of the water, the wetting of the skin, the facilitation of soil removal and dissolution, easy rinse-off and - if desired - foam regulation. Surfactants are typically understood to mean surface-active substances which have an HLB value of greater than 20.

[0066] Suitable surfactants include all those generally used in the field of cosmetic and personal care compositions and known to those skilled in the art.

[0067] The surfactants used may be anionic, nonionic, cationic, and / or amphoteric or zwitterionic surfactants. In surfactant-containing compositions, for example shower gels, foam baths, shampoos etc. at least one anionic surfactant is preferably present. In such embodiments, the anionic surfactant can be combined with another type of surfactant, typically with the exception of cationic surfactants, in particular nonionic or zwitterionic / ampholytic surfactants. In all embodiments disclosed herein, more than one surfactant of any type may be included, for example 2, 3, 4, 5 or more different (types of) surfactants. “Alkyl (ether) sulfates” and “fatty alcohol (ether) sulfates”, as used herein, relate to the well- known class of anionic surfactants of sulfated fatty alcohols and sulfated fatty alcohol ethers, in particular the ethoxylated, propoxylated or mixed ethoxylated / propoxylated ethers of fatty alcohols. Examples of such surfactants thus include sodium lauryl ether sulfate (SLES) and sodium lauryl sulfate (SLS or SDS). As disclosed herein below, it is preferred that these are only used in low amounts or the compositions are free of such surfactants.

[0068] Typical examples of usable nonionic surfactants are fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixed ethers and mixed formals, optionally partially oxidized alk(en)yl (poly)glycosides and glucuronic acid derivatives, fatty acid N- alkylglucamides, protein hydrolysates (especially wheat-based vegetable products), polyol fatty acid esters, sugar esters, sorbitan esters, polysorbates and amine oxides. If the nonionic surfactants contain polyglycol ether chains, they may have a conventional homolog distribution, but preferably have a narrow homolog distribution.

[0069] Zwitterionic surfactants refer to those surface-active compounds which bear at least one quaternary ammonium group and at least one -COO(-) or -SO3(-) group in the molecule. Particularly suitable zwitterionic surfactants are the betaines, such as the N-alkyl-N,N- dimethylammonium glycinates, for example cocoalkyl dimethylammonium glycinate, N- acylaminopropyl-N,N-dimethylammonium glycinates, for example cocoacylamino- propyldimethylammonium glycinate, and 2-alkyl-3-carboxymethyl-3-hydroxyethylimidazoline having in each case 8 to 18 carbon atoms in the alkyl or acyl group, and also cocoacylaminoethyl hydroxyethylcarboxymethyl glycinate.

[0070] Also suitable, especially as cosurfactants, are ampholytic surfactants. Ampholytic surfactants are understood to mean those surface-active compounds which, apart from a C8-C18-alkyl or acyl group in the molecule, contain at least one free amino group and at least one -COOH or -SO3H group and are capable of forming internal salts. Examples of suitable ampholytic surfactants are N-alkylglycines, N-alkylpropionic acids, N-alkylaminobutyric acids, N- alkyliminodipropionic acids, N-hydroxyethyl-N-alkylamidopropyhglycines, N-alkyltaurines, N- alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acids having in each case about 8 to 18 carbon atoms in the alkyl group. Particularly preferred ampholytic surfactants are N-cocoalkylaminopropionate, cocoacylaminoethyl-aminopropionate and C12-18- acylsarcosine. Typical examples of amphoteric or zwitterionic surfactants are alkyl betaines, alkylamidobetaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines.

[0071] Typical examples of anionic surfactants are soaps, alkylbenzenesulfonates, alkanesulfonates, olefin-sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, a-methyl ester sulfonates, sulfo fatty acids, mono- and dialkyl sulfosuccinates, mono- and dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ethercarboxylic acids and salts thereof, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, N-acylamino acids, for example acyl lactylates, acyl tartrates, acyl glutamates and acyl aspartates, alkyl oligoglucoside sulfates, protein fatty acid condensates (especially vegetable products based on wheat) and alkyl (ether) phosphates. If the anionic surfactants comprise polyglycol ether chains, these may have a conventional homolog distribution, but preferably have a narrow homolog distribution.

[0072] While the compositions may contain alkyl (ether) sulfates, including fatty alcohol (ether) sulfates, it is preferred that these are only present in low amounts of less than 2 wt.-%, such as 1 wt.-% or lower, or more preferred completely absent. In particular the rinse-off compositions disclosed herein are preferably free of such alkyl (ether)sulfates.

[0073] Cationic surfactants which can be used are especially quaternary ammonium compounds. Preference is given to ammonium halides, especially chlorides and bromides, such as alkyltrimethylammonium chlorides, dialkyldimethylammonium chlorides and trialkylmethylammonium chlorides, e.g. cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, lauryldimethylammonium chloride, lauryldimethylbenzylammonium chloride and tricetylmethylammonium chloride. In addition, the very readily biodegradable quaternary ester compounds, for example the dialkylammonium methosulfates and methylhydroxyalkyldialkyloxyalkylammonium methosulfates sold under the trade name Stepantex® and the corresponding products of the Dehyquart® series can also be used as cationic surfactants. The term “ester quats” are generally understood to mean quaternized fatty acid triethanolamine ester salts. These are known substances which are prepared by the relevant methods of organic chemistry. Further cationic surfactants which can be used in accordance with the invention are the quaternized protein hydrolysates.

[0074] Typical examples of particularly suitable mild, i.e. particularly skin-friendly, surfactants are mono- and / or dialkyl sulfosuccinates, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, fatty acid glutamates, a-olefinsulfonates, ether carboxylic acids, 2-sulfonated fatty acids, alkyl (poly)glycosides / -glucosides and / or mixtures thereof with alkyl oligoglucoside carboxylates, fatty acid glucamides, alkylamidobetaines, amphoacetals, protein hydrolysates, and / or protein fatty acid condensates, the latter preferably based on wheat proteins or salts thereof. These surfactants are preferred surfactants to be used in the compositions of the invention. In the compositions of the invention, these may be used individually or in combination.

[0075] Preferred surfactants are also generally those that are obtainable from renewable raw materials and are readily biodegradable.

[0076] Alk(en)yl (poly)glycosides (APGs) may be compounds of formula (I),

[0077] R1O-[G]P(I) in which R1is an alkyl and / or alkenyl radical with 4 to 18 carbon atoms, G is a sugar radical with 5 or 6 carbon atoms and p is numbers between 1 and 10. While such compounds are commonly referred to as alkyl glycosides or alkyl poly glycosides or alkyl oligo glycosides it is also possible that the alkyl moiety is an alkenyl radical. The term APG, as used herein, thus is intended to cover both alkyl and alkenyl (poly)glycosides.

[0078] APGs of the form claimed here can be obtained by the relevant methods of preparative organic chemistry. The APGs can be derived from aldoses or ketoses with 5 or 6 carbon atoms. While various sugar units may be used, in various embodiments, the sugar units of the APGs are derived from glucose.

[0079] The index number p in the general formula (I) indicates the degree of oligomerization (DP degree = degree of polymerization). The degree of oligomerization of the APGs is between 1 and 10 and preferably between 1 and 6. Whereas p in an individual APG molecule must always be an integer and here in particular assumes the values in the range from 1 to 6, the value p for an APG which is a mixture of different APG molecules, which differ in their individual p values, is an analytically determined calculated parameter which in most cases is a fraction. Preferably, APGs are used with an average degree of oligomerization p in the range from 1.1 to 3.0 or from 1.1 to 1 .8 or from 1.2 to 1 .7.

[0080] The average degree of oligomerization here is to be understood in the sense of how it is defined in the monograph K. Hill, W. von Rybinski, G. Stoll “Alkyl Polyglycosides. Technology, Properties and Applications” (VCH-Verlagsgesellschft, 1996) in the section “Degree of polymerization” (compare pages 11-12 of the book): there it reads “The average number of glycose units linked to an alcohol group is described as the (average) degree of polymerization (DP).” In explanatory figure 2, which describes a typical distribution of dodecyl glycoside oligomers of an AOPG with a degree of DP of 1.3, the average degree of DP is also described by a corresponding mathematical formula.

[0081] The radical R1is preferably derived from primary alcohols with 4 to 12 carbon atoms and preferably 8 to 10 carbon atoms. Typical examples of suitable radicals R1are butyl, hexyl, octyl, decyl, undecyl, dodecyl and myristyl. They are derived from the saturated fatty alcohols butanol-1 , caproic alcohol (hexanol-1), caprylic alcohol (octanol-1), capric alcohol (decanol-1), undecanol-1 , lauryl alcohol (dodecanol-1) and myristyl alcohol (tetradecanol-1), as are obtained for example in the hydrogenation of technical-grade fatty acid methyl esters or in the course of the hydrogenation of aldehydes during Roelen oxo synthesis.

[0082] Preference is given to APGs which are derived from glucose and in which the radical R1is a saturated alkyl radical with 8 to 12 carbon atoms and which have an average degree of oligomerization in the range from 1.1 to 3 and in particular in the range from 1.2 to 1.8 and particularly preferably in the range from 1 .2 to 1 .7. These APGs can for example be prepared by reacting a sugar, in particular glucose, under acid catalysis with a fatty alcohol mixture, the fatty acid mixture used preferably being a forerunning produced during the distillative separation of technical-grade Cs-is-coconut fatty alcohol, which comprises predominantly octanol-1 and decanol-1 and also small amounts of dodecanol-1.

[0083] Suitable 2-sulfonated fatty acids include, without limitation, 2-sulfolaurate and salts thereof, in particular disodium 2-sulfolaurate.

[0084] In various embodiments, the compositions of the invention include at least one surfactant. The at least one surfactant may be present in amounts of from 1 to 30 wt.-%, preferably 2 to 25 wt.-% or 5 to 25 wt.-% or 8 to 30 wt.-% or 10 to 25 wt.-% or 15 to 25 wt.-%, relative to the total weight of the composition. In various embodiments, the at least one surfactant is present in amounts of 5 to 20 or 10 to 15 wt.-%. Such surfactant-containing compositions may, in various embodiments, be the rinse-off compositions described herein.

[0085] In such surfactant-containing compositions, for example shower gels, foam baths, shampoos etc. at least one anionic surfactant is preferably present, preferably in combination with at least one nonionic or zwitterionic surfactant. In such embodiments, the at least one anionic surfactant and the at least one nonionic surfactant may be selected from the surfactants indicated as being preferred above. For example, the anionic surfactant may be a 2-sulfonated fatty acid, such as 2-sulfolaurate, and the nonionic surfactant may be an APG. The anionic surfactant may alternative be a sulfosuccinate or fatty acid glutamate and the nonionic / zwitterionic surfactant may be an alkylamidobetaine.

[0086] Further components

[0087] Depending on the intended application, the compositions of the invention can comprise a series of further auxiliaries and additives, such as, for example, preservatives, dyes, coloring agents, pigments, fragrances, humectants, emulsifiers, opacifiers, pearlescent agents, buffering and pH adjustment agents, conditioning agents and antioxidants. Suitable compounds are commercially available and well-known to those skilled in the art.

[0088] Suitable humectants, for example, include sorbitol, glycerol, propylene glycol, xylitol, liquid polyethylene glycol and mixtures thereof. If used in the compositions, the weight ratio of water to humectant is preferably at least 10:1 and up to 30:1 , with the total amount of humectant ranging from 2 to 8 wt.-%, relative to the total weight of the composition, for example 3 to 7 or 4 to 6 wt.-%.

[0089] In some embodiments, the compositions may comprise polyquaternium-10 (quaternized hydroxyethyl cellulose) as a conditioning agent. In such embodiments, the compositions are preferably rinse-off formulations, such as shower gels, shampoos and bath foams.

[0090] In various embodiments, the compositions of the invention comprise cationic guar gum, preferably guar hydroxypropyltrimonium salt, typically the chloride salt. Guar gum is a galactomannan polysaccharide extracted from guar beans that is known for its thickening and stabilizing properties useful in food applications. Cationic guar (gum) is obtained by quaternization of guar gum, the most common cationic guar being guar hydroxypropyltrimonium. It is typically used in form of its salt, in particular the chloride salt.

[0091] The compositions of the invention may optionally contain cationic guar in an amount of 0.01 to 1.0 wt.-%, preferably 0.2 to 0.6 wt.-%, relative to the total weight of the composition. In such embodiments, the compositions are preferably rinse-off formulations, such as shower gels, shampoos and bath foams.

[0092] The compositions of the invention are free of (poly)acrylate thickeners or, preferably, generally free of polyacrylates, including acrylate copolymers. In various embodiments, the compositions of the invention are generally free of synthetic polymeric thickeners. In some embodiments, the compositions do not contain any thickeners or rheology modifying agents other than xanthan gum and hydroxypropyl starch (phosphate). In this context, “thickeners” and “rheology modifiers” preferably refer to compounds only added for the purpose to increase or adjust viscosity and rheology and which do not function as other components of the composition, such as surfactants, emollients or any of the other auxiliary substances listed above.

[0093] The compositions of the invention are also free of organic UV filters selected from (hydroxy)benzophenones, ethylhexyl triazone, ethylhexyl methoxycinnamate, octocrylene, and ethylhexyl salicylate. In various embodiments, the compositions of the invention are also free of organic UV filters selected from (hydroxy)benzophenones, triazines, triazones, ethylhexyl methoxycinnamate, octocrylene, homosalate and ethylhexyl salicylate. In various embodiments, the personal care compositions of the invention are not sunscreens.

[0094] The compositions of the invention are also free of fluorinated organic compounds, more preferably free of halogenated organic compounds. This relates to organic compounds that have fluorine or any other halogen bonded by a covalent bond, but does not extend to halogen salts (halides).

[0095] The compositions of the invention are preferably also free of alkyl (ether) sulfate surfactants or contain those only in small amounts of less than 2 wt.-%, preferably 1 wt.-% or less.

[0096] The compositions of the invention are preferably also free of oxidizing agents, such as those used in hair dyes, in particular hydrogen peroxide or hydrogen peroxide generating compounds. In various embodiments, the compositions of the invention are not hair dyes.

[0097] The compositions of the present invention may be based, in various embodiments, predominantly on components derived from renewable raw materials. In various embodiments this may mean that more than 50 wt.-%, preferably more than 60, more than 70, more than 80 or more than 90 wt.-% of the components of the composition other than water are derived from renewable raw materials. It may be preferred that all non-water components are derived from renewable raw materials. Said renewable materials include, but are not limited to, plant-based materials. It may be preferred that less than 10 wt.-%, more preferably none of the non-water components of the compositions are derived from fossil sources or fossil fuels.

[0098] The compositions of the present invention may be based, in various embodiments, predominantly on components that are biodegradable. In various embodiments this may mean that more than 50 wt.-%, preferably more than 60, more than 70, more than 80 or more than 90 wt.-% of the components of the composition besides water are biodegradable. It may be preferred that all non-water components are biodegradable. The biodegradability is preferably determined according to OECD 301 F or OECD 302 C (MITI-II test), with ..biodegradable" components preferably having a biodegradability of at least 40%, preferably 60% determined according to OECD 301 F and / or at least 20%, preferably at least 40% according to OECD 302 C.

[0099] The compositions of the invention preferably have a pH at 20°C in the range of 3.5 to 7.0, preferably 4.0 to 6.5. more preferably 4.5 to 6.5, for example 4.8 to 5.2 or 6.0. to 6.2. The pH value may be determined directly or, preferably, as a 1% solution or dispersion in deionized water.

[0100] The viscosity of the compositions is preferably at least 2.000 mPa.s (determined at 20°C in a Brookfield DV-I+, Spindle 4, 10 rpm) and may be as high as 50.000 mPa.s (determined at 20°C in a Brookfield DV-I+, Spindle TC, Helipath, 10 rpm).

[0101] Another subject of the present invention is a cosmetic composition comprising water, the dispersion according to the present invention, and optionally one or more further cosmetically acceptable ingredients, wherein the dispersion is obtainable according to the process according to the present invention.

[0102] In one embodiment the cosmetic composition according to the present invention comprises 0.2 to 99 % by weight water, preferably 10 to 99 % by weight water, and the dispersion according to the present invention in an amount that leads to an amount of 0.1 to 5 % by weight of heat-treated xanthan in the cosmetic composition.

[0103] The cosmetic composition according to the present invention comprises the dispersion according to the present invention. This means that it comprises the components comprised in this dispersion. It does not necessarily mean that the dispersion structure is upheld, i. e. the heat-treated xanthan is not necessarily dispersed in the cosmetically acceptable oil once the dispersion, together with other substances forms the cosmetic composition.

[0104] The fact circumstance that the cosmetic composition comprises a dispersion according to the present invention which is obtainable according to the process according to the present invention for making the dispersion results in a cosmetic composition which is different from, and has advantageous properties compared to, a cosmetic composition comprising a dispersion of heat-treated xanthan in a cosmetically acceptable oil, which has been obtained by a different process, e. g. by heat-treating xanthan powder and dispersing the heat-treated powder in a cosmetically acceptable oil. Further information in this regard is presented in the following paragraphs. Examples to support the said differences are presented in the experimental part of the present patent application.

[0105] Advantages

[0106] The subjects of the present invention have numerous advantages compared to the state of the art. Some of these are described in the following paragraphs.

[0107] The dispersion according to the present invention has a high storage stability. It can contain a high amount of heat-treated xanthan gum. Incorporation of the dispersion into aqueous formulations results in smooth, unstructured emulsions, especially if the dispersion is obtained according to the process according to the present invention for making a dispersion of heat- treated xanthan gum in a cosmetically acceptable oil. Contrary to this, dispersing heat-treated xanthan gum powder having a high average particle size in water generally leads to coarse gel or emulsion structures. Also, heat-treating xanthan powder, dispersing it in an oil and then using the dispersion for making a cosmetical formulation results in coarse gel or emulsion structures.

[0108] The dispersion according to the present invention is biodegradable to a great extent and especially useful for cosmetic and pharmaceutical uses.

[0109] The process according to the present invention has the advantage that the amount of water added can be kept low. This means that subsequently only a low amount of water must be removed to produce the dispersion according to the present invention. This is favorable due to low energy consumption and little time that is needed in the water-removal process. Processes for making a dispersion of xanthan in oil disclosed in the state of the art, which start with an aqueous solution of xanthan in water do not have these advantages as they need to use higher amount of water, because highly concentrated solutions of xanthan in water have high viscosities and are difficult to process.

[0110] It is assumed that the fact that an aqueous solution of heat-treated xanthan gum has a higher viscosity than an aqueous solution of xanthan gum that has not been heat-treated is due to cross-linking of the xanthan gum during heat-treatment.

[0111] The use of a dispersion of heat-treated xanthan gum in a cosmetically acceptable oil as a cosmetic raw material is advantageous over xanthan powder use (faster incorporation, no dust problems such as explosion hazard or toxicological problems due to inhalation of dust). In order to obtain xanthan-in-oil dispersions with superior properties with regard to storage stability against sedimentation as well as fine gel or emulsion structures in the application, very small xanthan particles in the oil phase in the range of xso<25 pm, especially < 10 pm are advantageous. Xanthan powders available in the market are essentially too coarse to be used directly for making dispersion in oil with good properties.

[0112] A process disclosed in the state of the art to make a dispersion of xanthan in oil is to dissolve the xanthan in water, to emulsify the xanthan solution in the oil and to remove the water. However, dispersions with high concentrations of xanthan cannot easily be produced with this process. When dispersing considerable amounts of dry xanthan in water, the viscosity increases rapidly to an extent that makes it difficult to incorporate and hydrate large clusters and lumps of dry, not wetted xanthan. Furthermore, the stickiness and viscosity of the resulting gel is high, so that the production of fine emulsions with droplets in the size range below 10 pm is very challenging with conventional emulsification devices like stirred vessels, rotor- stator-dispersing-machines, high pressure homogenizers or ultrasound sonotrodes and the like because of the high viscosity ratio between aqueous and oil phase.

[0113] Examples

[0114] In the following text % means % by weight unless a different definition is given.

[0115] Materials used Comparative Example 1

[0116] 260 g of the Xanthan powder were put on tray and stored in a vacuum oven at 120°C for 4.5 hours. The particle size dso of the powder was determined by Laser Diffraction Particle Size Analyzer to be 85.8 microns. 2 w.-% of the powder were stirred into water. After 24 h, a coarse gel with a viscosity of 26.700 mPas (Brookfield viscosimeter; spindle 6, 20 rpm, room temperature) had formed. The surface of the gel was rough and matte, the gel contained many visible gel lumps (so called “fish eyes”). When the powder was added to a low viscous emulsion of emollient 1 in water at a concentration of 2 w.-%, the material gave a viscous emulsion. The appearance of the emulsion was dull and non-glossy, visibly containing very coarse gel particles.

[0117] Example 1

[0118] An emulsion was prepared in the following manner:

[0119] Dispersion Step 1 : To 401 g of Emollient 1 were added 88 g of Additive 1 and 176 g of Additive 5 solution (20 w.-% in Emollient 1). Using a dissolver disc with a diameter of 40 mm, 264 g of Xanthan gum were added within 2 minutes time. Under external cooling with ice, 660 g of demineralized water were added slowly while dispersing at 6000 rpm for 4 minutes; stirring was continued for another 10 minutes. The emulsion was kept at room temperature for 24 h. Dispersion Step 2: After the maturation time, the emulsion was dispersed using a dissolver disk at 6000 rpm and a rotor / stator batch shear unit with 15 mm outer rotor diameter at 30.000 rpm at the same time (4 cycles, each 2.5 minutes). The temperature was controlled not to exceed 40 °C. According to light-microscopic pictures, the xanthan-water droplets obtained in the Emollient 1 were smaller than 20 pm.

[0120] 400 g of the emulsion were transferred to a stirred reactor and maintained at 35 °C for 24 hours under stirring while a vacuum of 20 mbar was applied. The vacuum was reduced to 300 mbar and the temperature raised to 120 °C within 20 mins. The reactor was kept at that temperature for 2 hours, then cooled to room temperature. The particle size dso of the dispersion was determined by Laser Diffraction Particle Size Analyzer to be 5.4 microns.

[0121] The whitish dispersion did not sediment upon standing at room temperature.

[0122] 14.1 g of the dispersion were stirred into 185.3 g of water, leading to a raise in viscosity. After stirring for 24 hours, the viscosity was determined using a Brookfield viscosimeter (spindle 6, 20 rpm, room temperature) to be 21800 mPas. A smooth and stable emulsion was obtained. When applied to skin, a very nice, rich and velvety feeling was obtained. The gel-like behaviour was non-wobbly and not slimy. An emulsion using the same composition of the starting material components without following above protocol had a viscosity of 4300 mPas and much poorer sensual properties.

[0123] In a separate experiment, 0.2 w.-% of Additive 2 were added to the dispersion. The stability of the dispersion was not affected by the addition. When the dispersion was added to water, the raise to final viscosity occurred within less than 5 minutes.

[0124] Example 2

[0125] In a similar manner as above, an emulsion was prepared from 16.6 w.-% Xanthan gum, 41.5 w.-% water, 2.2 w.-% Additive 6, 5.5 w.-% Additive 1 and 34.1 w.-% Emollient 1.

[0126] 400 g of the emulsion were transferred to a stirred reactor and maintained at 35°C for 24 hours under stirring while a vacuum of 20 mbar was applied. The vacuum was reduced to 300 mbar and the temperature raised to 120°C within 20 mins. The reactor was kept at that temperature for 2 hours, then cooled to room temperature.

[0127] The whitish dispersion was stable upon standing at room temperature.

[0128] The dispersion was stirred into water in an amount to yield a mixture containing 2 w.-% of Xanthan gum. After stirring for 24 hours, the viscosity was determined to be 18500 mPas. A smooth and stable emulsion was obtained.

[0129] Examples 3 - 13

[0130] In a similar manner as examples 1 and 2 the following materials have been prepared.

[0131] An emulsion containing 2 w.-% of the polysaccharide was evaluated as above.

[0132] Biodegradation of Example 10 was tested according to OECD 301 F. The sample was readily biodegradable with a degradation of 90% after 28 days and > 60% within 10 days.

[0133] Examples 14 - 17

[0134] Example 14

[0135] An aqueous xanthan solution-in-oil emulsion was prepared by using a Polytron high shear mixing head with one rotor and one stator tooth rim and an outer rotor diameter of 26 mm in the second dispersing step. The device was operated at a rotational speed of 30000 rpm in 4 cycles of 2.5 minutes each. The temperature was controlled not to exceed 40°C. The second dispersing step was carried out immediately after dispersing step 1 without swelling time. In comparison to example 1 , an emulsion with a finer droplet size in the range of below 5 microns was obtained.

[0136] Example 15

[0137] An aqueous xanthan solution-in-oil emulsion was prepared by using a Polytron high shear mixing head with two rotor and two stator tooth rims and an outer rotor diameter of 31 mm at a rotational speed of 15000 rpm in the second dispersing step. The second dispersing step was carried out after 4 hours swelling time following dispersing step 1 in two cycles of one minute each. The temperature was controlled not to exceed 50°C. The droplets in the emulsion were essentially below 5 microns.

[0138] Example 16

[0139] After dispersion step 1 similar to example 1 and a swelling time of 24 h, the emulsion was dispersed with a high shear rotor stator machine (Cavitron CD1000) at a rotational speed of 17000 rpm and a flow rate of 1.3 kg / h in one single pass. Without further cooling, the product temperature at the outlet of the machine reached 54 °C. Light-microscopic images showed droplets essentially smaller than 10 pm.

[0140] Example 17

[0141] After dispersion step 1 similar to example 1 and a swelling time of 24 h, the emulsion was dispersed with a high-pressure homogenizer APV2000. The homogenization pressure was set to 500 bar in the first dispersing stage and 50 bar in the second stage. The emulsion was passed through the device for 6 times at a flow rate of approximately 10 kg / h with intermediate cooling between the passes in order not to exceed 45°C. After 3 passes, light-microscopic images showed droplets essentially smaller than 20 pm.

[0142] Example 18

[0143] To a mixture of 1365 g of emollient 1 , 222 g of additive 5 und 89 g of additive 5 were added 1000 g of xanthan powder under stirring. To this suspension, 1663 g of water were added and stirred for 1 h. Afterwards, the mixture was passed over a Cavitron CD 1000 rotor-stator unit operating at 17.000 rpm during 20 minutes. This process was repeated 5 times. Light- microscopic images of the resulting emulsion showed droplets essentially smaller than 20 pm. The water was removed from the emulsion using vacuum distillation at elevated temperature. Afterwards, the reactor was heated to 120°C for 6 hours under vacuum.

[0144] The particle size dso of the dispersion was determined by Laser Diffraction Particle Size Analyzer to be 6.8 microns. The whitish dispersion did not sediment upon standing at room temperature.

[0145] 10.7 g of the dispersion were vigorously stirred into 188.7 g of water, leading to a raise in viscosity. After resting for 24 hours, the viscosity was determined using a Brookfield viscosimeter (spindle 6, 20 rpm, room temperature) to be 24400 mPas. A smooth and stable emulsion was obtained. The emulsion had a very nice and glossy appearance. When applied to skin, a very nice, rich and velvety feeling was obtained. The gel-like behaviour was non- wobbly and not slimy.

[0146] Examples 19-22

[0147] In a similar manner as examples 1 and 2 the following materials have been prepared.

[0148] An emulsion containing 2 w.-% of the polysaccharide was evaluated as above.

[0149]

[0150] Example 23

[0151] Solutions of 4 w.-% xanthan gum in water were adjusted with 10 w.-% NaOH to a desired pH value and the solution afterwards freeze-dried in a conventional lab freeze-dry apparatus. The resulting dry solid material was spread into trays, which were put into a vacuum oven at 120°C for 2 hours. Afterwards, the powders were dispersed in water to obtain a 2 w.-% aqueous gel. The Brookfield viscosity was determined at room temperature at 20 rpm of the corresponding spindle:

[0152] Sample 1 pH = 7,7 (not adjusted) 15800 mPas

[0153] Sample 2 pH = 8,0 10000 mPas

[0154] Sample 3 pH = 9,0 7350 mPas

[0155] This example shows that the intensity of crosslinking due to heat-treatment and thus viscosity of an aqueous solution of heat-treated xanthan gum depends on the pH value of the starting material. The lower the pH value the more crosslinking occurs and thus the higher is the viscosity of an aqueous solution of the heat-treated xanthan gum.

Claims

Claims1. A dispersion comprising at least one cosmetically acceptable oil and heat-treated xanthan, wherein the heat-treated xanthan is dispersed in the cosmetically acceptable oil, and wherein heat-treated means that the xanthan has been in contact with water, the water having a pH value of 1 or higher and 9 or less and, after the water has been removed, the xanthan has been kept at a temperature of 110°C to 150°C for 0.5 to 12 hours.

2. The dispersion according to claim 1 further comprising water.

3. The dispersion according to claim 1 or 2 further comprising at least one emulsifier.

4. The dispersion according to any of claims 1 to 3 further comprising at least one stabilizer.

5. The dispersion according to any of claims 1 to 4, comprising 30 to 80 % by weight of the at least one cosmetically acceptable oil, 10 to 55 % by weight of heat-treated xanthan, 1 to 25 % by weight of the at least one emulsifier, and 0 to 5 % by weight of the at least one stabilizer.

6. The dispersion according to any of claims 1 to 5, wherein the dispersion is essentially free of any volatile oil, wherein a volatile oil is an aliphatic or cycloaliphatic hydrocarbon that is different from the cosmetically acceptable oil and has a boiling point of 250 °C or less, and wherein free of means less than 2 % by weight.

7. The dispersion according to any of claims 1 to 6, wherein the average particle size of the heat-treated xanthan dso is equal to or less than 25 pm, wherein dso is determined by Fraunhofer diffraction measurements carried out with the dispersion.

8. A process for making the dispersion according to any of claims 1 to 7 comprising providing the cosmetically acceptable oil, adding xanthan in the form of a powder to the oil, so that a xanthan-in-oil dispersion is obtained, adding water to the xanthan-in-oil dispersion, so that a dispersion of xanthan plus water in oil is obtained, optionally permitting a swelling time, wherein this swelling time preferably is 0.1 to 24 hours, reducing the average particle size of the dispersion of xanthan plus water in oil byapplying shearing, preferably by stirring the dispersion of xanthan plus water in oil, removing at least some of the water present in the dispersion of xanthan plus water in oil, heat-treating the dispersion, wherein this heat-treating can partially or totally occur while removing the at least some of the water or thereafter.

9. The process according to claim 8, wherein the amount of water added is 0.5 to 3 times the amount of the xanthan, wherein amount means mass.

10. The use of the dispersion according to any of the preceding claims for making a cosmetic composition.

11. A process for making a cosmetic composition by mixing the dispersion according to any of the preceding claims with one or more further cosmetically acceptable ingredients.

12. A cosmetic composition comprising water, the dispersion according to any of the preceding claims, and optionally one or more further cosmetically acceptable ingredients, wherein the dispersion is obtainable by the process according to claim 8 or 9.

13. The cosmetic composition according to claim 12 comprising0.2 to 99 % by weight water, and the dispersion according to any of the preceding claims in an amount that leads to an amount of 0.1 to 5 % by weight of heat-treated xanthan in the cosmetic composition.

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