Foam containing hydrogen gas

Abstract

The invention relates to a foam having a gas phase and an aqueous liquid phase, the gas phase making up at least 50 vol.% of the foam and substantially comprising hydrogen gas, and the aqueous liquid phase comprising at least one dissolved and / or dispersed emulsifier, and the liquid phase, diluted with 30 g of water per 0.1 g of liquid phase, having a surface tension of 40 to 90 mN / m at 20°C. The foam can be applied safely and easily. A formulation for producing the foam contains at least one emulsifier which is soluble or dispersible in water. The foam can be used in a cosmetic product or as a cosmetic product, in a medical product or as a medical product, or in a food or as a food.

Description

[0001] Foam containing hydrogen gas

[0002] Description

[0003] The present invention relates to a foam containing hydrogen gas, a formulation for producing a foam containing hydrogen gas, a process for producing the foam and the use of the foam.

[0004] Hydrogen gas exhibits antioxidant and anti-inflammatory effects, which may be of interest in dermal applications in cosmetics, medicine, or as a food additive or dietary supplement. However, hydrogen gas is flammable even at relatively low concentrations of 4% by volume in air, making its safe use a technological challenge. Furthermore, the gas's volatility also poses practical challenges.

[0005] To make volatile hydrogen accessible to consumers, three basic technological solutions exist: finished products that already contain the hydrogen, hydrogen-producing electrical on-demand generators, or chemical hydrogen generators / storage devices that produce / release hydrogen immediately before or during use.

[0006] A particularly interesting application is hydrogen gas foam, which can contain large amounts of gas in its bubbles. Such hydrogen gas foam should be dimensionally and volume-stable and non-flammable throughout the application and / or storage period. Current approaches to this type of foam fail to achieve these goals.

[0007] JP 2018 / 024613 A describes an industrially produced, finished cosmetic and its preparation, which is described as a "hydrogen gas-containing viscous composition." The cosmetic is a finished gel or cream containing up to 70% by volume of hydrogen gas, which is produced using several manufacturing steps and hydrogen gas.

[0008] WO 2016 / 010139 A1 describes a cosmetic product containing a metal or metal hydride powder mixed with a semi-fluid material such as a gel, cream, paste, or mousse. Contacting the powder with moisture or a semi-fluid material releases hydrogen gas or produces a hydrogen-containing composition.

[0009] WO 2022 / 191757 A1 describes a composition and the production process of a foam for fire extinguishing, comprising a phospholipid or a hydrogenated phospholipid. The surface tension of the foam required for fire extinguishing is suitably below 18 mN / m. KR 10-2021-0034530 describes a hydrogen gas-generating composition comprising a self-assembling peptide, a hydrogen compound, an acid, and a carrier. It is stated that the self-assembling peptide creates a thin nanofilm on the surface of an aqueous solution or on the surface of a solid carrier to retain the hydrogen gas in the aqueous solution.

[0010] US 2018 / 0092816 A describes a composition for dermal application comprising a hydrogen-generating compound or molecular hydrogen and a carrier containing a phosphatidylcholine component. It is explained that the phosphatidylcholine component encloses the hydrogen-generating compound or molecular hydrogen in the composition. Examples of products containing hydrogen gas include gels, creams, lotions, and ointments. A foam or the materials required for it are not discussed.

[0011] JP 2021 / 013376 A describes an industrially produced gel-like composition comprising 10 to 90 vol% hydrogen and at least one thickener and one emulsifier. The gel-like composition is described as suitable for use in food or cosmetics and is produced using several manufacturing steps, including heating, technical aids, and hydrogen gas.

[0012] WO 2018 / 131505 A1 describes an industrially produced ready-to-use gel and its preparation, which comprises 1 to 70 vol% hydrogen gas and a thickener. The finished gel is intended for use as a cosmetic or food product.

[0013] The invention is based on the object of providing foams containing hydrogen gas which can be used safely and easily.

[0014] The object is achieved by a foam having a gas phase and an aqueous liquid phase, wherein the gas phase makes up at least 50 vol% of the foam and essentially comprises hydrogen gas, and the aqueous liquid phase comprises at least one dissolved and / or dispersed emulsifier, and the liquid phase, diluted with 30 g of water per 0.1 g of liquid phase, has a surface tension at 20 °C of 40 to 90 mN / m.

[0015] It has been found that the surface tension of the liquid phase is of critical importance. While common surfactants greatly reduce the interfacial or surface tension and form surface films, the hydrogen gas foams formed are very liquid, fast-flowing, flammable and not volume-stable. In contrast, hydrogen gas can be finely dispersed in foams with a liquid phase according to the invention and forms bubbles with a small diameter, which makes the foam non-flammable. In addition, the foam according to the invention is characterized by particularly high dimensional and volume stability, which is advantageous, for example, in dermal application. The foam according to the invention is particularly fine-pored and therefore has relatively small hydrogen gas bubbles. The average diameter of the gas bubbles is preferably a maximum of 1.5 mm, more preferably a maximum of 1.0 mm and most preferably a maximum of 0.6 mm.The mean diameter of the gas bubbles can be determined using light transmission, for example with a Krüss Dynamic Foam Analyzer DFA100.

[0016] In one embodiment, the reduction in foam volume within 60 minutes after providing the foam is a maximum of 25 vol%, preferably a maximum of 20 vol%.

[0017] In a further embodiment, the reduction in foam volume within four weeks after provision of the foam is a maximum of 25 Vol-%, preferably a maximum of 20 Vol-%.

[0018] The gas phase of the foam makes up at least 50% by volume of the foam and is dispersed in the aqueous liquid phase. Preferably, the gas phase makes up at least 70% by volume of the foam, more preferably at least 80% by volume, more preferably at least 90% by volume, at least 93% by volume, or at least 95% by volume.

[0019] The gas phase essentially comprises hydrogen gas, preferably at least 60 vol%, more preferably at least 90 vol%, most preferably at least 95 vol%, at least 98 vol% or at least 99 vol% hydrogen gas.

[0020] The aqueous liquid phase comprises at least one emulsifier. The emulsifier and the other components of the aqueous liquid phase, if present, are water-soluble or at least water-dispersible. The term "water-soluble" refers to a solubility in water at 20 °C of at least 0.1 g / L. The term "water-dispersible" refers to the component being dispersible in water.

[0021] The aqueous liquid phase is characterized by a specific surface tension. The surface tension can be determined using the Du Noüy ring method, e.g., according to the method specified in the experimental section. The measurement is carried out on a dilute aqueous solution of the liquid phase. For this purpose, a sample of the liquid phase is introduced into a volume of deionized water so that the liquid phase is diluted by 30 g of water per 0.1 g of liquid phase. For practical purposes, a measured amount of the foam can also be used instead of the pure liquid phase. The liquid phase has a surface tension at 20 °C of 40 to 90 mN / m, preferably 50 to 90 mN / m, and particularly preferably 60 to 80 mN / m.

[0022] In one embodiment, the individual dissolved or dispersed components of the liquid phase are each characterized in that an aqueous solution or dispersion of the component in the proportional concentration in which the component is present in the liquid phase has a surface tension at 20 °C of at least 40 mN / m, preferably at least 50 mN / m and particularly preferably at least 60 mN / m, wherein the aqueous solution or dispersion is diluted for measurement in an analogous manner with 30 g of water per 0.1 g of solution or dispersion.

[0023] The aqueous liquid phase preferably has a viscosity at 25°C that is higher than that of water, preferably a viscosity of 100 or more mPa-s, preferably 100 to 20,000 mPa-s, more preferably 100 to 5,000 mPa-s, most preferably 100 to 3,500 mPa-s. The viscosity can be determined using a rotational rheometer according to the method specified in the experimental section.

[0024] The aqueous liquid phase comprises at least one emulsifier, i.e., a surfactant. Certain emulsifiers have the ability to stabilize foam. The emulsifier can be selected from amphoteric, anionic, cationic, and / or nonionic emulsifiers.

[0025] In one embodiment, the emulsifier is selected from membrane-forming lipids, for example, phospholipids, sphingolipids such as ceramides, glycolipids, and sulfatides. Phospholipids such as lecithins are particularly noteworthy. Lecithins are mixtures of phosphoglycerides, including, in particular, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidic acid. Phosphatidylcholines are esters of fatty acids, glycerol, phosphoric acid, and choline. Phosphatidylcholines typically contain units of unsaturated fatty acids such as oleic acid or linolenic acid.

[0026] Lecithin can be synthetically produced or technically extracted, for example, as an extract from egg yolk, soybeans, sunflowers, corn, and / or rapeseed, preferably as an extract from sunflowers. In addition to the aforementioned phosphoglycerides such as phosphatidylcholine, technically extracted products contain other impurities such as neutral fat from the extraction source. The term "lecithin" refers to the overall composition, which may contain phosphatidylcholine and other phosphoglycerides, as well as other phospholipids and neutral fat.

[0027] In a preferred embodiment, the emulsifier is selected from hydrogenated membrane-forming lipids, especially hydrogenated lecithins.

[0028] Non-limiting examples are hydrogenated lecithin (CAS No. 92128-87-5), hydrogenated phosphatidylcholine (CAS No. 97281-48-6), or hydrogenated lysolecithin (CAS No. 97281-48-6). These are obtained by hydrogenating lecithin, phosphatidylcholine, or lysolecithin, respectively, preferably from industrially produced lecithin, phosphatidylcholine, or lysolecithin. The hydrogenation is typically carried out in the presence of a hydrogenation catalyst in an organic solvent.

[0029] The hydrogenated lecithin preferably comprises phosphatidylcholine in an amount of at least 60 wt.%, preferably at least 75 wt.%, particularly preferably at least 85 wt.%, such as at least 90 wt.% or at least 95 wt.%. Hydrogenated lecithins are commercially available, for example Lipoid® P 100-3 or Phospholipon® 90 H (Lipoid) 90 H, Epikuron® 100 H or 200 SH (Cargill), Cosphaderm® SF-75-H or SB-75-H (Cosphatec), or Emulmetik® 320 (Lucas Meyer Cosmetics).

[0030] In a preferred embodiment, the aqueous liquid phase comprises hydrogenated lecithin in an amount of 3 to 100 wt.%, based on the solids content of the aqueous liquid phase. The term "solids content" refers here and below to the total amount of dissolved or dispersed components of the aqueous liquid phase. In a particularly preferred embodiment, the aqueous liquid phase comprises hydrogenated lecithin in an amount of 100 wt.%, based on the solids content of the aqueous liquid phase. In this case, hydrogenated lecithin is the sole emulsifier.

[0031] In one embodiment, the emulsifier is selected from saponins. Saponins are glycosides of steroids, steroid alkaloids, or triterpenes and are widespread in higher plants. Saponins are found in high concentrations in chestnuts and in the bark of the South American soap bark tree, Quillaja saponaria.

[0032] Saponins can be produced synthetically or extracted technically, particularly as an extract from Quillaja saponaria. The term "saponins" refers to the overall composition, which may contain other plant substances in addition to saponins.

[0033] In a preferred embodiment, the emulsifier is selected from Quillaja saponins. Suitable Quillaja saponins are commercially available, for example, ANDEAN QDP ULTRA ORGANIC or ANDEAN QD (Desert King) or Foamex® Quillaja Extract Powder 60 (Garuda).

[0034] In a preferred embodiment, the aqueous liquid phase comprises saponins from Quillaja in an amount of 0.1 to 15 wt.%, in particular 0.1 to 5 wt.%, based on the solids content of the aqueous liquid phase.

[0035] In one embodiment, the emulsifier is selected from saponins and / or phosphoglycerides, in particular from saponins from Quillaja and / or hydrogenated lecithins.

[0036] The emulsifier typically has a significant influence on the surface tension of the aqueous liquid phase. The influence on surface tension can be concentration-dependent for some emulsifiers. In one embodiment, the aqueous liquid phase also comprises a thickener. Thickeners are substances that can bind water and increase the viscosity of a liquid phase by removing unbound water. Most thickeners are linear or branched macromolecules, such as polysaccharides or proteins. It is possible for a substance to act as both an emulsifier and a thickener.

[0037] In one embodiment, the thickener is selected from polysaccharides. Polysaccharides are long-chain polymeric carbohydrates consisting of monosaccharide units linked by glycosidic bonds. Examples of polysaccharides include glycogen, starch such as amylose and amylopectin, pectins, chitin, callose, and cellulose.

[0038] Polysaccharides can be produced synthetically or obtained technically, for example, as an extract from Tremella. Tremella is a mushroom and belongs to the so-called jelly-like family, which forms gelatinous to cartilaginous fruiting bodies. A special feature of Tremella mushrooms is that their pharmacologically active polysaccharides make up the majority of the structural polysaccharides of the fruiting body, whereas in other medicinal mushrooms, the pharmacologically active polysaccharides make up only a small part of the biomass.

[0039] The most important pharmacologically active substance in Tremella is the polysaccharide glucuronoxylomannan, consisting of a long α-mannose chain with various two- to three-membered oligosaccharide side chains of β-mannose, α-mannose, β-xylose, and β-glucuronic acid, which are O-acetylated at the terminal mannoses. The chemical structure of Tremella glucuronoxylomannan varies between different specimens of a species. The general ratio of xylose:glucuronic acid:mannose is given as 1.0:2.77:4.9 in Tremella fuciformis; 2:1:4 in T. aurantia; and 7:1:5 in T. mesenterica (see Fraser et al., 1973, Can. J. Biochem.). 51 : 219 to 224. Some additional saccharides were identified in various samples of T. fuciformis, such as glucose, fucose, xylobiose and fructose.

[0040] Technically produced polysaccharides contain impurities in addition to polysaccharides. The term "polysaccharide" refers to the overall composition, which may include other plant compounds in addition to polysaccharides.

[0041] Suitable Tremella polysaccharides are commercially available, for example, Tremella fuciformis polysaccharide (REB Technology), Tremoist TP™ (Nippon), and Phytocare-HA™ (applechem). In a preferred embodiment, the aqueous liquid phase comprises Tremella polysaccharides in an amount of 0.1 to 15 wt.%, especially 1 to 9 wt.%, based on the solids content of the aqueous liquid phase.

[0042] In a particularly preferred embodiment, the aqueous liquid phase comprises an emulsifier selected from saponins, in particular saponins from Quillaja, and a thickener selected from polysaccharides, in particular polysaccharides from Tremella. The aqueous liquid phase preferably comprises saponins from Quillaja in an amount of 0.1 to 15 wt.%, in particular 0.1 to 5 wt.%, and polysaccharides from Tremella in an amount of 0.1 to 15 wt.%, in particular 1 to 9 wt.%, based on the solids content of the aqueous liquid phase.

[0043] The foams described here may contain additional components in addition to those described above. Particularly suitable are excipients that do not reduce the stability of the foam and maintain the surface tension and viscosity of the aqueous liquid phase discussed above. This also includes reaction products or incompletely reacted substances from chemical reactions that can release hydrogen gas.

[0044] Examples of suitable excipients include, in particular, particulate components that have a stabilizing effect in Pickering emulsions, for example, microparticles such as spray-dried soy protein particles, hydrophobically modified starch particles, and / or natural spore particles; and nanoparticles such as cellulose nanocrystals, flavonoid (tiliroside) particles, chitin nanocrystals, ethylcellulose particles, chemically modified starch nanospheres, corn protein (zein) particles, and / or solid lipid particles. Minerals (e.g., talc, mica, diatomaceous earth, illite) with a particle size of 10 nm to 300 pm are also suitable additives.

[0045] The auxiliaries are preferably present in a total amount of 0 to 80 wt.%, particularly preferably in a total amount of 0 to 40 wt.%, based on the solids content of the aqueous liquid phase.

[0046] In one embodiment, the foam according to the invention additionally comprises a non-aqueous liquid phase which forms an emulsion together with the aqueous liquid phase.

[0047] The non-aqueous liquid phase comprises, for example, an oil. The oil is preferably selected from polyol fatty acid polyesters and mineral oils, as well as mixtures thereof. The oil is particularly preferably selected from triglycerides of synthetic, semi-synthetic, and natural origin, as well as mixtures thereof. Examples include triheptanoin, squalane, coconut oil such as MCT oil, olive oil, sunflower oil, soybean oil, peanut oil, rapeseed oil, almond oil, palm oil, castor oil, wheat germ oil, grape seed oil, safflower oil, evening primrose oil, macadamia nut oil, corn germ oil, avocado oil, and the like. In one embodiment, the foam according to the invention does not comprise a non-aqueous liquid phase.

[0048] The foams described here are understood to be liquid foams. Liquid foam comprises gaseous bubbles enclosed within liquid walls. The foam is preferably a watery foam. The foam is easily spreadable and its consistency is comparable, for example, to that of shaving foam.

[0049] The foam according to the invention is suitable, for example, for dermal application, i.e., for topical application to the skin. Preferred dermal applications include cosmetic applications and medical applications, in particular cosmetic applications. For example, the foam can be used to improve the skin's appearance, such as to reduce skin irritations.

[0050] The invention further relates to the use of the foam according to the invention in a cosmetic product or as a cosmetic product, in a medical product or as a medical product, or in a food or as a food. The foam according to the invention can be added, for example, to creams, gels, mousses, or beverages.

[0051] Furthermore, additives can be added to the foam according to the invention. Non-limiting examples include colorants, fragrances or flavorings, foodstuffs, food additives, cosmetic and pharmaceutical active ingredients.

[0052] The pH of the foam according to the invention is preferably in the range of 4.0 to 7.0, in particular 4.0 to 5.0, as determined at 20°C under normal pressure, when applied at a pH-neutral skin level; when applied in a basic manner, the pH is above 7.0, but not higher than 10.35, as determined at 20°C under normal pressure.

[0053] The invention also relates to a formulation for producing the hydrogen gas-containing foam according to the invention, comprising at least one water-soluble or water-dispersible emulsifier as described above.

[0054] The individual components of the formulation according to the invention can be liquid, gel-like, or solid, for example, powdered. The individual components of the formulation according to the invention, and thus the formulation itself, can be water-containing or anhydrous.

[0055] The formulation according to the invention preferably comprises one or more pH regulators. pH regulators are understood to be compounds that change the pH of aqueous liquids, i.e., both acids and bases. The pH regulator(s) advantageously promote or accelerate the release of hydrogen gas. The formulation preferably comprises 2 to 90 wt.% of the pH regulator, preferably 10 to 85 wt.%, particularly preferably 30 to 75 wt.%, based on the total weight of the formulation.

[0056] The pH regulator is selected from acids, such as mineral acids, hydroxycarboxylic acids and amino acids, and bases, such as metal hydroxides.

[0057] Suitable mineral acids include sulfuric acid, nitric acid, phosphoric acid and / or hydrochloric acid.

[0058] Suitable hydroxycarboxylic acids include tartronic acid and fruit acids such as citric acid, lactic acid, mandelic acid, tartaric acid and / or malic acid.

[0059] Suitable amino acids include glutamic acid.

[0060] Suitable metal hydroxides include sodium hydroxide and / or potassium hydroxide.

[0061] The pH regulator preferably comprises a fruit acid, such as citric acid, lactic acid, mandelic acid, tartaric acid, or malic acid. In a particularly preferred embodiment, the pH regulator comprises citric acid.

[0062] The invention also relates to a foam according to the invention, produced by dispersing hydrogen gas in a formulation according to the invention. In this case, the formulation preferably contains water or water is added.

[0063] The invention also relates to a process for producing a hydrogen gas-containing foam, comprising dispersing hydrogen gas in a formulation as described above in the presence of water. The water can be added to the formulation or already present in the formulation. The foam can be produced at temperatures below 40°C, preferably at ambient temperature, such as about 20°C.

[0064] The dispersion can be carried out under a hydrogen gas atmosphere and by introducing or impacting the hydrogen gas into the aqueous formulation, similar to the production of cream, for example.

[0065] To disperse the hydrogen gas, hydrogen gas can also be introduced into the aqueous formulation while simultaneously mixing it. A nozzle or a porous gas diffuser can be used for this purpose. To ensure a sufficiently high power input, a mixing device, such as a hand mixer, a disperser, or a milk frother, is typically used for mixing.

[0066] In one embodiment, the process is carried out under a hydrogen gas atmosphere and with simultaneous introduction of hydrogen gas. Electrical aids such as ultrasonic devices, dispersers, and / or hand mixers can be used in the process. Production with electrical aids enables the creation of very small bubbles in the nanoscale.

[0067] It has been found that dispersing hydrogen gas in the aqueous formulation allows the provision of a particularly creamy and very stable foam.

[0068] The foam of the invention prepared by dispersing hydrogen gas can be stored in a suitable package with minimal hydrogen gas permeability, such as an aluminum foil bag, until use.

[0069] In a preferred embodiment, the formulation contains a compound that generates hydrogen gas upon contact with water. In this case, the formulation is preferably in powder form.

[0070] The formulation preferably comprises 0.5 to 20 wt.% of the particulate compound which generates hydrogen gas with water, preferably 2 to 18 wt.%, particularly preferably 3 to 15 wt.%, based on the solids content of the formulation.

[0071] Preferably, the hydrogen gas-generating compound is selected from a metallic powder, an alkali metal hydride, an alkaline earth metal hydride, and / or a metal borohydride. The hydrogen gas-generating compound can be coated, e.g., with a polysaccharide such as pullulan.

[0072] Suitable metallic powders include alkali metals such as sodium and / or potassium; and alkaline earth metals such as magnesium and / or calcium.

[0073] Suitable alkali metal hydrides include lithium hydride (LiH), sodium hydride (NaH) and / or potassium hydride (KH).

[0074] Suitable alkaline earth metal hydrides include magnesium hydride (MgH2), calcium hydride (CaH2), barium hydride (BaH2), beryllium hydride (BeH2) and / or strontium hydride (SrH2).

[0075] Suitable metal borohydrides include lithium borohydride (LiBH4) and sodium borohydride (NaBH4).

[0076] The hydrogen gas-generating compound is preferably selected from alkali metal hydrides, alkaline earth metal hydrides, and / or metal borohydrides, in particular alkaline earth metal hydrides and / or metal borohydrides. In a preferred embodiment, the hydrogen gas-generating compound is selected from magnesium hydride and / or sodium borohydride, and is in particular magnesium hydride.

[0077] The hydrogen gas-generating compound is in particulate form. The hydrogen gas-generating compound preferably has an average particle size in the range of 0.1 to 100 μm, preferably 0.1 to 30 μm, particularly preferably 0.1 to 20 μm. A particle size in these ranges allows the release of small hydrogen gas bubbles from the hydrogen gas-generating compound, thus producing a fine-pored foam.

[0078] In a preferred embodiment, the formulation comprises: a) 0.5 to 20 wt.% of a compound that generates hydrogen gas with water; b) 3 to 90 wt.% of the emulsifier; c) 2 to 90 wt.% of the pH regulator; and c) 100 wt.% of optional ingredients; based on the total weight of the formulation.

[0079] The desired amount of hydrogen gas can be adjusted by the amount of hydrogen-generating compound and / or the amount of pH regulator.

[0080] The invention also relates to a process for producing a foam containing hydrogen gas, comprising mixing a formulation as described above with water.

[0081] The formulation can also be presented as a multi-component system. The multi-component system can contain an aqueous component. The constituents forming the aqueous liquid phase can be distributed arbitrarily among the individual components, whereby the hydrogen-generating compound is not included in the aqueous component.

[0082] To produce a foam containing hydrogen gas, the components of the multicomponent system are mixed, with additional water optionally being added. Hydrogen gas is generated by reacting the aqueous components of the multicomponent system with the hydrogen gas-generating compound, resulting in a foam according to the invention.

[0083] The foam can be easily prepared by manually mixing the formulation with water, for example, using a spoon. The resulting foam is stable over a typical application period, for example, up to 75 minutes. The foam can be prepared at temperatures below 40°C, preferably at ambient temperature, such as approximately 20°C.

[0084] The invention is illustrated by the following examples. Examples

[0085] The following measurements and examples were performed at an ambient temperature of approximately 20 °C unless otherwise stated.

[0086] Method 1 : Determination of surface tension

[0087] The following laboratory materials were used:

[0088] 1) 1 aluminum ring - diameter (D = 2 xr) 60mm - approx. 5g with 3 threads with a hook for hanging on a precision force gauge

[0089] 2) Precision force gauge (0.1 N maximum tensile force)

[0090] 3) Laboratory lifting platform

[0091] 4) Beaker (600 mL)

[0092] 5) Tripod base, tripod rod and bracket

[0093] 6) Distilled water

[0094] The aqueous liquid phase of a foam or the foam itself is used as the sample material. The sample material is diluted in a beaker with 30 g of water per 0.1 g of sample material and stirred by hand. The beaker is placed on the laboratory lift. The precision force gauge is suspended from the support rod via a hook attached to a sleeve.

[0095] The aluminum ring is suspended from the force gauge and placed above the beaker. The laboratory lift is slowly raised until the ring is completely submerged in the water. The force upon immersion (F1) is read on the precision force gauge. The laboratory lift is slowly lowered until the liquid lamella breaks away. The force at the moment of breakaway (F2) is read on the precision force gauge.

[0096] The surface tension o in mN / m is calculated using the following formula: o = (F2 - F1) / (4 * TT * r)

[0097] Method 2: Determination of viscosity

[0098] A rotational rheometer (also called a rotational viscometer) is used. In a rotational rheometer, a motor rotates a body in the liquid. During rotation, the required torque is measured. From this, as well as the exact geometry of the rotating body used and the rotational speed, the dynamic viscosity of the liquid can then be determined. A DVNext Wells-Brookfield cone / plate rheometer was used as the measuring device. The viscosity was determined at 25 °C.

[0099] Method 3: Inflammability

[0100] A sample of approximately 20 mL of the foam to be tested is taken with a spatula and touched to the flame of a lit lighter. The foam is considered "flammable / combustible foam" if it visually exhibits one of the following properties:

[0101] 1 ) The foam ignites almost completely;

[0102] 2) The foam ignites on its surface;

[0103] 3) The foam ignites partially; or

[0104] 4) Several individual blisters become inflamed.

[0105] Method 4: Foam stability

[0106] A Krüss Dynamic Foam Analyzer - DFA100 was used to determine the foam stability.

[0107] Two grams of a foamable powder composition are placed in the DFA100 measuring column and mixed with 6 grams of water. The mixture is then stirred manually for 20 seconds using a glass rod and then analyzed using the DFA100.

[0108] The development of foam volume over time and the proportion of hydrogen gas were determined. The following parameters and conditions were used for the analysis:

[0109] - Software: ADVANCE 1.15

[0110] Instrument: DFA100 + FSM

[0111] Sample holder: SH4503

[0112] - Temperature: Room temperature

[0113] Column: CY4573 (40mm prism short)

[0114] Height illumination: Blue LED, 14%

[0115] Structural lighting: 20%

[0116] Camera height: 55 mm

[0117] Camera position: ••

[0118] Measurement frequency: 0.5 fps (height); 0.1 fps (structure)

[0119] Inventive Example 1-1

[0120] 6 g of hydrogenated lecithin (Phospholipon® 80 H, Lipoid) was mixed in powder form with 40 g of distilled water (proportion of hydrogenated lecithin to the liquid phase: 13 wt%) and whipped with an electric milk frother under a hydrogen gas atmosphere at room temperature. The resulting fine-pored foam was creamy, stable over the 24-hour test period, and non-flammable.

[0121] The following properties were determined:

[0122] Surface tension: 74 mN / m

[0123] - Viscosity: greater than 100 mPa-s

[0124] - Hydrogen gas in foam: 77 vol.%

[0125] Foam volume immediately after production: 200 mL

[0126] Foam volume after 60 min: 200 mL

[0127] Foam volume after 24 h: 195.5 mL (reduction of 2.25%)

[0128] Inventive Example 1-2

[0129] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 3 g hydrogenated lecithin (Cosphaderm SF-75H, Cosphatec) and 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer) were mixed.

[0130] The powder mixture was placed in a bowl and quickly mixed with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds, resulting in a fine-pored foam.

[0131] The foam was tested for flammability and stability. It was found that the resulting foam was stable and non-flammable for the duration of 30 minutes of face mask use.

[0132] The following properties were determined:

[0133] Surface tension: 74 mN / m

[0134] - Viscosity: greater than 100 mPa-s

[0135] - Hydrogen gas in foam: 92 vol.%

[0136] Foam volume immediately after production: 180 mL

[0137] Foam volume after 60 min: 150 mL (reduction of 16.7%)

[0138] Inventive Example 1-3

[0139] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.04 g Quillaja wood extract (ANDEAN QDP ULTRA, Desert King), 0.07 g Tremella Fuciformis Polysaccharide (Tremoist TP, Nippon) and 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer) were mixed.

[0140] The powder mixture was placed in a bowl and quickly mixed with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds, resulting in a fine-pored foam.

[0141] The foam was tested for flammability and stability. It was found that the resulting foam was stable and non-flammable for the duration of 30 minutes of face mask use.

[0142] The following properties were determined:

[0143] Surface tension: 72 mN / m

[0144] - Viscosity: greater than 100 mPa-s

[0145] - Hydrogen gas in foam: 94 vol.%

[0146] Foam volume immediately after production: 180 mL

[0147] Foam volume after 60 min: 150 mL (reduction of 16.7%)

[0148] Inventive Example 1-4

[0149] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.04 g Quillaja wood extract (ANDEAN QDP ULTRA, Desert King), 1 g hydrogenated lecithin (Cosphaderm SF-75H, Cosphatec), 0.07 g Tremella Fuciformis polysaccharide (Tremoist TP, Nippon) and 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer) were mixed.

[0150] The powder mixture was placed in a bowl and quickly mixed with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds, resulting in a fine-pored foam.

[0151] The foam was tested for flammability and stability. It was found that the resulting foam was stable and non-flammable for the duration of 30 minutes of face mask use.

[0152] The following properties were determined:

[0153] Surface tension: 74 mN / m

[0154] - Viscosity: greater than 100 mPa-s

[0155] - Hydrogen gas in foam: 93 vol.%

[0156] Foam volume immediately after production: 180 mL

[0157] Foam volume after 60 min: 160 mL (reduction of 11.1%) Practical example: Dermal application

[0158] A foam according to the invention, as prepared according to Examples 1-1 to 1-5 below, is applied to previously cleansed skin, for example, the face (approximately 200 mL of foam generated per facial application). The composition is allowed to act for a period of, for example, 10 to 30 minutes and is then rinsed off with water.

[0159] The applied foam remains stable and non-flammable throughout the application period. Furthermore, it stays stable on the face and doesn't run. The foam "collapses" toward the skin, releasing a large amount of hydrogen gas and moisture into the skin.

[0160] Comparison example 2-1

[0161] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer), 2.3 g sodium laurylglucoside hydroxypropylsulfonate and silica gel (SugaNate 160 Dry, ColonialChemie) were mixed.

[0162] The powder mixture was placed in a bowl and stirred briskly with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds to produce a foam.

[0163] The foam was tested for flammability and stability. It was found that the resulting foam was flammable immediately after production ("flammable / flammable foam": Section 4).

[0164] The following properties were determined:

[0165] Surface tension: 37 mN / m

[0166] - Viscosity: greater than 100 mPa-s

[0167] - Hydrogen gas in foam: 78 vol.%

[0168] Foam volume immediately after preparation: 60 mL

[0169] Foam volume after 60 min: 40 mL (reduction of 33.3%)

[0170] Comparison example 2-2

[0171] 0.1 g of magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.6 g of citric acid (Citric Acid Monohydrate, Jungbunzlauer), and 2.3 g of sodium cocoyl isethionate (HOSTAPON SCI 85 P, Clariant) were mixed. The powder mixture was placed in a bowl and stirred briskly with 10 g of distilled water using a spatula at room temperature for about 20 seconds, resulting in a foam.

[0172] The foam was tested for flammability and stability. It was found that the resulting foam was flammable immediately after production ("flammable / flammable foam": Section 4).

[0173] The following properties were determined:

[0174] Surface tension: 34 mN / m

[0175] - Viscosity: greater than 100 mPa-s

[0176] - Hydrogen gas in foam: 74 vol.%

[0177] Foam volume immediately after preparation: 50 mL

[0178] Foam volume after 60 min: 30 mL (reduction of 40%)

[0179] Comparison example 2-3

[0180] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer) and 2.3 g sodium lauryl sulfoacetate were mixed.

[0181] The powder mixture was placed in a bowl and stirred briskly with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds to produce a foam.

[0182] The foam was tested for flammability and stability. It was found that the resulting foam was flammable immediately after production ("flammable / flammable foam": Section 4).

[0183] The following properties were determined:

[0184] Surface tension: 30 mN / m

[0185] - Viscosity: greater than 100 mPa-s

[0186] - Hydrogen gas in foam: 78 vol.%

[0187] Foam volume immediately after preparation: 60 mL

[0188] Foam volume after 60 min: 30 mL (reduction of 50%) Comparative example 2-4

[0189] 0.1 g magnesium hydride (MgH2, Zegen Metals & Chemicals), 0.6 g citric acid (Citric Acid Monohydrate, Jungbunzlauer) and 2.3 g sucrose cocoate (TEGOSOFT LSE 65 K SOFT, Evonik) were mixed.

[0190] The powder mixture was placed in a bowl and stirred briskly with 10 g of distilled water using a spatula by hand at room temperature for about 20 seconds to produce a foam.

[0191] The foam was tested for flammability and stability. It was found that the resulting foam was flammable immediately after production ("flammable / flammable foam": point 1).

[0192] The following properties were determined:

[0193] Surface tension: 18 mN / m

[0194] - Viscosity: greater than 100 mPa-s

[0195] - Hydrogen gas in foam: 87 vol.%

[0196] Foam volume immediately after production: 100 mL

[0197] Foam volume after 60 min: 0 mL (completely disintegrated)

[0198] It is evident that foam stability strongly depends on the surface tension of the aqueous liquid phase. The foams according to the invention exhibit high stability and are non-flammable.

[0199] Comparative Examples 2-1 to 2-3 produced a foam with an inhomogeneous bubble size distribution and, in some cases, relatively large bubbles with a visually determined size of greater than or equal to 2 mm. Such hydrogen gas foams were found to be flammable. Comparative Example 2-4 initially produced a fine-pored foam, which, however, quickly coalesced to bubble sizes of greater than or equal to 3 mm. This foam ignited almost completely.

Claims

Claims 1 . Foam with a gas phase and an aqueous liquid phase, wherein the gas phase makes up at least 50 vol% of the foam and essentially comprises hydrogen gas, and the aqueous liquid phase comprises at least one dissolved and / or dispersed emulsifier, and the liquid phase, diluted with 30 g of water per 0.1 g of liquid phase, has a surface tension at 20 °C of 40 to 90 mN / m.

2. Foam according to claim 1, wherein the average diameter of the gas bubbles is a maximum of 1.5 mm, preferably a maximum of 1.0 mm and most preferably a maximum of 0.6 mm.

3. Foam according to claim 1 or 2, wherein the reduction in foam volume within 60 minutes after production of the foam is a maximum of 25 vol%, preferably a maximum of 20 vol%.

4. Foam according to claim 1 or 2, wherein the reduction in foam volume within four weeks after production of the foam is a maximum of 25% by volume, preferably a maximum of 20% by volume.

5. Foam according to one of the preceding claims, wherein the liquid phase has a viscosity at 25 °C which is increased compared to water, preferably a viscosity of 100 mPa-s or more.

6. Foam according to one of claims 1 to 5, wherein the emulsifier is selected from saponins and / or phosphoglycerides, preferably from saponins from quillaja and / or hydrogenated lecithin.

7. Foam according to one of the preceding claims, wherein the aqueous liquid phase further comprises a thickener, preferably a polysaccharide, more preferably a polysaccharide from Tremella.

8. A formulation for producing a hydrogen gas-containing foam according to any one of claims 1 to 5, comprising at least one water-soluble or water-dispersible emulsifier.

9. Formulation according to claim 8, wherein the emulsifier is selected from saponins and / or phosphoglycerides, preferably from saponins from Quillaja and / or hydrogenated lecithin.

10. Formulation according to claim 8 or 9, further comprising a thickener, preferably at least one polysaccharide, in particular a polysaccharide from Tremella.

11. Formulation according to one of claims 8 to 10, further comprising a pH regulator, which is in particular selected from mineral acids, hydroxycarboxylic acids, amino acids and metal hydroxides.

12. Formulation according to claim 11, wherein the pH regulator is a hydroxycarboxylic acid, in particular a fruit acid, such as citric acid, lactic acid, mandelic acid, tartaric acid or malic acid, preferably citric acid.

13. A formulation according to any one of claims 8 to 12 for producing a hydrogen gas-containing foam by mixing with water, containing a compound which generates hydrogen gas upon contact with water.

14. Formulation according to claim 13 in powder form.

15. A formulation according to claim 13 or 14, wherein the hydrogen gas generating compound is selected from a metallic powder, an alkali metal hydride, an alkaline earth metal hydride and / or a metal borohydride.

16. A formulation according to claim 15, wherein the hydrogen gas generating compound is sodium borohydride or magnesium hydride, in particular magnesium hydride. A formulation according to any one of claims 13 to 16, comprising: a) 0.5 to 20 wt.% of the compound which generates hydrogen gas upon contact with water; b) 3 to 90 wt.% of the emulsifier; c) 2 to 90 wt.% of the pH regulator; and c) 100 wt.% of optional ingredients, based on the total weight of the formulation. A process for producing a foam containing hydrogen gas, comprising dispersing hydrogen gas in a formulation according to any one of claims 8 to 12. Use of a foam according to any one of claims 1 to 7 in a cosmetic product or as a cosmetic product, in a medicinal product or as a medicinal product, or in a food or as a food.