Pickering Lotion

Abstract

The present invention relates to a Pickering emulsion comprising: (i) water; (ii) 10-50 wt% of oil, based on the total weight of the Pickering emulsion, and (iii) 1-10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm. 50 Value. In addition, the present invention relates to a composition comprising the Pickering emulsion and a method for preparing such a Pickering emulsion. The present invention also relates to the use of calcium carbonate particles as a Pickering pigment for stabilizing a Pickering emulsion, the Pickering emulsion comprising water and 10-50 wt% of oil, based on the total weight of the Pickering emulsion, wherein the calcium carbonate particles are selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and have a volume median particle size d of 0.2 μm-10 μm. 50 value.

Description

[0001] The present invention relates to a Pickering emulsion comprising: (i) water; (ii) 10-50 wt% of oil, based on the total weight of the Pickering emulsion; and (iii) 1-10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm. 50 The present invention also relates to a composition comprising the Pickering emulsion and a method for preparing the Pickering emulsion. The present invention also relates to the use of calcium carbonate particles as a Pickering pigment for stabilizing a Pickering emulsion comprising water and 10-50 wt % of oil, based on the total weight of the Pickering emulsion, wherein the calcium carbonate particles are selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC) and have a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0002] The term "emulsion" generally refers to a heterogeneous system consisting of two immiscible or nearly immiscible liquids (which are usually referred to as phases). One of the two liquids is dispersed in the other liquid in the form of fine droplets. However, in order to obtain a durable dispersion of one liquid in the other, it is usually necessary to add a surfactant (emulsifier). Such emulsifiers generally have an amphiphilic molecular structure, which consists of a polar (hydrophilic) and a non-polar (lipophilic) part of the molecule that are spatially separated from each other.

[0003] In a simple emulsion, finely dispersed droplets of one phase (water droplets in a water-in-oil [W / O] emulsion or lipid vesicles in an oil-in-water [O / W] emulsion) are present in a second phase surrounded by an emulsifier shell. Emulsifiers reduce the interfacial tension between the two phases by placing themselves at the interface between the two liquids. At the phase boundary, they form an oil / water interfacial film that prevents the droplets from irreversibly coalescing. Emulsifier mixtures are often used to stabilize emulsions.

[0004] However, such emulsifiers can have disadvantages. Some known emulsifiers are harmful or even toxic to humans or nature. Some emulsifiers can trigger allergies. Furthermore, emulsifiers add additional cost to the final product.

[0005] Therefore, emulsifier-free emulsions are often used. This type of emulsion is a special form of emulsion. These emulsions do not contain emulsifiers in the narrow sense, that is, low molecular weight (molecular weight <5000) amphiphilic compounds that form micelles and / or other liquid crystalline aggregates at higher concentrations. In addition, these substances increase the stability of the emulsion by reducing the rate of aggregation and / or coalescence.

[0006] However, another type of emulsion is the Pickering emulsion. In the early 20th century, Pickering prepared paraffin / water emulsions that were stabilized solely by the addition of colloidal solids. This type of emulsion is therefore also known as a Pickering emulsion. In a Pickering emulsion, the solids accumulate in a layer at the oil / water boundary surface, thereby preventing the dispersed particles from binding. In this regard, the wetting properties of the solid particles (which should be wettable by both the hydrophilic and lipophilic phases) are particularly important. Pickering emulsions are encountered in various natural and industrial processes, such as crude oil recovery, oil separation, cosmetic preparation, wastewater treatment, food compositions, and the like.

[0007] One known Pickering pigment is calcium carbonate. One advantage of calcium carbonate is that it is non-toxic and can therefore also be used in cosmetic preparations, food preparations, or compositions for use in the environment. Such a composition is known, for example, from the article by Zhang et al., “Emulsion phase inversion from oil-in-water (1) to water-in-oil-oil inwater (2) induced by in situ surface activation of CaCO3 nanoparticles via adsorption of sodium stearate”, Physicochem. Eng. Aspects 477, 2015, pp. 55–62, which relates to calcium carbonate nanoparticles activated as an emulsifier by interaction with sodium stearate, and the size of the calcium carbonate nanoparticles is typically 10-100 nm. Another article is “Effect of trace impurities in triglyceride oils on phase inversion of Pickering emulsions stabilized by CaCO3 nanoparticles” by Zhu et al., Physicochem. Eng. Aspects 417, 2013, pp. 126–132, which relates to oil-in-water or water-in-oil emulsions stabilized with CaCO3 nanoparticles, wherein the emulsion contains a trace amount of anionic surfactant such as sodium lauryl sulfate or sodium carboxylate as a hydrophobic agent, which hydrophobizes the surface of the CaCO3 nanoparticles, wherein the primary diameter of the nanoparticles is 80 nm to 120 nm. From the article "Multiple Phase Inversion of Emulsion Stabilized by in Situ Surface Activation of CaCO Nanoparticles via Adsorption of Fatty Acids" by Cui et al., Langmuir, 2012, 28, pp. 314-320, it is known that hydrophilic CaCO nanoparticles (which have been surface activated with sodium carboxylates of chain length 6-12 and sodium 2-ethylhexyl sulfosuccinate) can be used to stabilize oil-in-water or water-in-oil emulsions at the interface, wherein the calcium carbonate particles are nanoparticles and have a primary diameter of 80-120 nm. However, all these Pickering emulsions contain nanoparticles less than 120 nm. Recent studies have shown that such small nanoparticles can be detrimental to the environment, humans, and animals.More precisely, these nanoparticles enter the body during ingestion or through the skin and can relocate to various organs and tissues within the body or settle within plants. Due to their reactivity within human, animal, or plant cells, they can exhibit toxicological effects. More precisely, these nanoparticles have the ability to bind to proteins, and due to this binding, some particles can produce adverse biological consequences through protein stretching, fibrillation, thiol crosslinking, and loss of enzyme activity. Therefore, Pickering particles with a primary diameter greater than 150 nm are desirable.

[0008] US20100272765A1 relates to a stable emulsion and a method for preparing the same. The average particle size of the solid particulate material in the emulsion is at most 200 nm. The emulsion comprises: (a) oil; (b) water; (c) a surfactant; and (d) a solid particulate material, wherein the surfactant may be any anionic, zwitterionic or amphoteric, nonionic or cationic surfactant known to those skilled in the art. WO2009112836 relates to a Pickering emulsion formulation comprising: (a) an aqueous continuous phase; (b) a dispersed oil phase comprising at least one substantially water-insoluble insecticide active ingredient; (c) at least one colloidal solid stabilizer located at the interface between the continuous phase and the dispersed phase, the number-weighted median particle size of which may be 0.5 μm or less; and (d) at least one polymeric co-stabilizer. JP2017508441A relates to an edible emulsion comprising at least one aqueous phase and at least one lipid phase, which is stabilized by edible inorganic salt particles, wherein the edible inorganic salt can be calcium carbonate and the particles are coated or adsorbed with 0.5-20wt% of fatty acids on their surface. The article "On the Pickering emulsions stabilized by calcium carbonate particles with various morphologies" by Huang Funing et al., Colloids and Surfaces A 580(2019)123722, relates to cubic, spherical and rod-shaped calcium carbonate particles (PCC particles), which are prepared by a precipitation method and used as stabilizers to form Pickering emulsions. The Pickering emulsions stabilized by calcium carbonate particles are of the oil-in-water type. The article "Pickering Emulsions stabilized by Calcium Carbonate Particles: A New Topical Formulation" by Joana Marto et al., Cosmetics 2020, 7, 62, 7030062, relates to the use of calcium carbonate particles as stabilizers for topical Pickering emulsions. The formulations prepared in this article have pH and shear thinning properties compatible with human skin and contain caprylic / capric triglycerides and calcium carbonate, which is derived from the crushing of limestone aggregates and is therefore a ground natural calcium carbonate (GCC). The solid particles or pigments used as Pickering pigments are often ground calcium carbonate particles or precipitated calcium carbonate particles. However, when PCC or GCC particles are used as Pickering pigments, the droplet size is often not very uniform, and these emulsions are often unstable, for example, a separated oil phase can be detected after a few days.Therefore, in order to produce a stable Pickering emulsion, it is often necessary to add a surfactant, a stabilizer, or a surface coating to the surface of the Pickering pigment. The addition of such surfactants, stabilizers, or surface coatings is often undesirable, particularly in Pickering emulsions for agricultural use or for use on humans and animals, because such compounds may have side effects on humans or animals and may not be environmentally friendly.

[0009] Therefore, there is a continuing need in the art for alternative or improved Pickering emulsions.

[0010] It is an object of the present invention to provide a Pickering emulsion comprising novel Pickering pigments which have not been used as Pickering pigments before. It is a further object of the present invention to provide a Pickering emulsion which is free of nanoparticles having a primary diameter below 150 nm. It is a further object of the present invention to provide a Pickering emulsion wherein the emulsion does not contain, in addition to the Pickering pigments, further emulsifiers for stabilizing the droplets in the Pickering emulsion. It is a further object of the present invention to provide a Pickering emulsion which is more environmentally compatible. It is a further object of the present invention to provide a Pickering emulsion which can be produced easily and quickly, which is inexpensive and in particular easy to dispose of.

[0011] The aforementioned and other problems are solved by the subject matter defined herein in the independent claims.

[0012] According to one aspect of the present invention, there is provided a Pickering emulsion comprising: (i) water; (ii) 10-50 wt% of oil, based on the total weight of the Pickering emulsion; and (iii) 1-10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0013] The inventors of the present invention have surprisingly found that for the preparation of Pickering emulsions it is advantageous to use Pickering pigments which are calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), wherein the calcium carbonate particles have a volume median particle size d in the range of 0.2 μm to 10 μm. 50First, the Pickering pigment of the present invention has a volume median particle size d of 0.2 μm to 10 μm. 50 The Pickering emulsions of the present invention contain no further emulsifiers for stabilizing the droplets in the Pickering emulsion in addition to the Pickering pigment, so that a clean label emulsion can be produced. In addition, the Pickering pigments of the present invention are non-toxic and harmless to the environment, humans or animals. In addition, the inventors have found that the Pickering emulsions of the present invention are white, even when colored, for example yellow, oils are used. Finally, the inventors have surprisingly found that the Pickering emulsions of the present invention can be easily and quickly produced, are inexpensive and, in particular, easy to dispose of.

[0014] According to another aspect of the present invention, there is provided a composition comprising the Pickering emulsion of the present invention, wherein the composition is a food composition, a cosmetic composition, a pharmaceutical composition or a nutritional formula milk powder.

[0015] According to another aspect of the present invention, there is provided a method for preparing a Pickering emulsion, the method comprising the steps of: A) providing water, B) providing oil, and C) providing a Pickering pigment, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d greater than 0.1 μm to 10 μm. 50 %, D) combining the water of step A), the oil of step B) and the Pickering pigment of step C) in any order to obtain a mixture comprising 10 to 50 wt % of the oil based on the total weight of the mixture and 1 to 10 wt % of the Pickering pigment based on the total weight of the mixture, and E) mixing the mixture obtained in step D) to prepare a Pickering emulsion.

[0016] According to another aspect of the present invention, calcium carbonate particles are used as Pickering pigments to stabilize a Pickering emulsion comprising water and 10-50 wt% of oil, based on the total weight of the Pickering emulsion, wherein the calcium carbonate particles are selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and have a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0017] Advantageous embodiments of the above-mentioned aspects are defined in the corresponding dependent claims.

[0018] According to one embodiment of the present invention, the ground calcium carbonate is selected from marble, limestone and / or chalk, preferably marble, and / or

[0019] Surface reacted calcium carbonate is natural ground calcium carbonate or precipitated calcium carbonate reacted with carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + The ion donor process is formed in situ and / or supplied from an external source.

[0020] According to another embodiment of the present invention, the ground calcium carbonate has:

[0021] a) Volume median particle size d of 0.3 μm to 5.0 μm 50 Value, preferably 0.6μm-3μm, most preferably higher than 1.0μm-1.7μm, and / or

[0022] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, and / or

[0023] c) 0.5-50 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 0.5-35m 2 / g, more preferably 0.5-25m 2 / g, most preferably 0.6-17m 2 / g.

[0024] According to another embodiment of the present invention, the surface-reacted calcium carbonate has:

[0025] a) Volume median particle size d of 1.5 μm to 9.0 μm 50 value, preferably 2.5 μm-7.5 μm, most preferably 3.3 μm-6.6 μm, and / or

[0026] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, and / or

[0027] c) 10-200 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 20-180m 2 / g, more preferably 25-140m 2 / g, most preferably 48-110m 2 / g, and / or

[0028] d) 0.1-2.3 cm calculated by mercury intrusion method 3 / g of the particle internal pressure-injection specific pore volume, more preferably 0.2-2.0cm 3 / g, particularly preferably 0.4-1.5cm 3 / g, most preferably 0.6-1.1cm 3 / g,.

[0029] According to another embodiment of the present invention, the emulsion comprises 10-40 wt% oil, preferably 10-30 wt% oil, most preferably 10-20 wt% oil, based on the total weight of the Pickering emulsion.

[0030] According to another embodiment of the invention, the oil:

[0031] selected from mineral oils, vegetable oils, animal fats, essential oils and mixtures thereof, preferably selected from essential oils, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil and mixtures thereof, preferably selected from sunflower oil, olive oil, palm oil and / or coconut oil, most preferably sunflower oil, and / or

[0032] It is a refined oil having an acid value of less than 0.6, preferably less than 0.5, most preferably less than 0.3, or an unrefined oil having an acid value of less than 4.0, preferably less than 3.0, most preferably less than 2.0.

[0033] According to another embodiment of the present invention, the emulsion comprises 2-10 wt% of Pickering pigment, preferably 4-10 wt% of Pickering pigment, most preferably 6-10 wt% of Pickering pigment, based on the total weight of the Pickering emulsion.

[0034] According to another embodiment of the invention, the emulsion comprises an additional active ingredient, preferably selected from the group consisting of cosmetically active compounds, pharmaceutically active compounds, nutritional additives, flavoring agents and mixtures thereof.

[0035] According to another embodiment of the present invention, the emulsion is stable against coalescence for at least 15 days, more preferably at least 20 days, most preferably at least 30 days.

[0036] According to another embodiment of the invention, the emulsion contains no further emulsifiers, besides the Pickering pigments, for stabilizing the droplets in the Pickering emulsion.

[0037] According to another embodiment of the present invention, the surfaces of the Pickering pigments and preferably the surface-reacted calcium carbonate particles provided in step C) are not coated with a surface treatment agent.

[0038] An "emulsion" within the meaning of the present invention is a mixture of two or more generally immiscible liquids, one of which is dispersed in the other. A "Pickering emulsion" within the meaning of the present invention is an emulsion in which the Pickering pigments accumulate in a layer at the oil / water boundary surface, thereby preventing dispersion from combining. A "Pickering pigment" within the meaning of the present invention is a pigment that accumulates at the oil / water boundary surface of the droplets in the Pickering emulsion and stabilizes them. A "pigment" within the meaning of the present invention is an inorganic solid material with a defined chemical composition and characteristic crystalline structure. Pigments are insoluble in water and oil.

[0039] Oils within the meaning of the present invention are compounds which are liquid at 25° C. and 1.0 bar and which do not form a homogeneous mixture when mixed with water.

[0040] "Ground natural calcium carbonate" (GNCC) in the meaning of the present invention is calcium carbonate obtained from natural sources, such as limestone, marble or chalk, and processed by wet and / or dry treatments such as grinding, sieving and / or classification, for example by cyclones or classifiers.

[0041] " precipitated calcium carbonate " (PCC) is the synthetic material that obtains usually by carbon dioxide and calcium hydroxide (slaked lime) reaction postprecipitation in aqueous environment or by calcium source and carbonate source precipitation in water in the meaning of the present invention.In addition, precipitated calcium carbonate can also be the product that for example introduces calcium salt and carbonate, calcium chloride and sodium carbonate in aqueous environment.PCC can have vaterite, calcite or aragonite crystalline form.PCC is described in for example EP2447213A1, EP2524898A1, EP2371766A1, EP2840065A1 or WO2013142473A1.

[0042] The surface-reacted calcium carbonate according to the present invention is prepared by reacting CO2 and one or more H3O + Ion donor treatment of the reaction product of ground natural calcium carbonate (GNCC) or precipitated calcium carbonate (PCC) where CO2 is reacted with H3O + The ion donor is generated in situ and / or supplied from an external source. + Ion donors in the context of the present invention are Brønsted acids and / or acid salts.

[0043] The "particle size" of Pickering pigments is described as the volume-based particle size distribution d x (vol). Among them, the value d x (vol) represents the diameter at which x vol% of the particles have a diameter smaller than d x (vol). This means that for example d 20The (vol) value is the particle size at which 20 vol% of all particles are smaller than this particle size. 50 The (vol) value is the volume median particle size, that is, 50 vol% of all particles are smaller than this particle size, and d 98 The (vol) value is the particle size at which 98 vol% of all particles are smaller than this particle size. 50 The evaluation was performed using a Malvern Mastersizer 2000 Laser Diffraction System. The raw data obtained by the measurement was analyzed using Mie theory, and the particle refractive index was 1.57 and the absorption index was 0.005.

[0044] For materials other than Pickering pigments, such as ground calcium carbonate or precipitated calcium carbonate used to prepare surface-reacted calcium carbonate, the “particle size” is expressed as its particle size distribution. x (wt) is used to describe the value of d. x (wt) represents the diameter relative to which x wt% of the particles have a diameter smaller than d x (wt). This means that for example d 20 The (wt) value is the particle size at which 20 wt% of all particles are smaller than this particle size. 50 The (wt) value is the weight median particle size, that is, 50 wt% of all particles are smaller than this particle size. This measurement is made using a Sedigraph from Micromeritics Instrument Corporation, USA. TM The method and instrument are known to those skilled in the art and are commonly used to determine particle size distribution. The measurement is carried out in a 0.1 wt% aqueous solution of Na4P2O7. The sample is dispersed using a high-speed stirrer and ultrasound.

[0045] Throughout this paper, the “specific surface area” (m 2 The adsorption capacity (A / g) is determined using the BET method (using nitrogen as adsorption gas), which is well known to those skilled in the art (ISO 9277:2010).

[0046] For the purposes of the present invention, "porosity" or "pore volume" refers to the volume of pores packed into a particle. The porosity or pore volume is measured using a Micromeritics Autopore V 9620 mercury intrusion porosimeter.

[0047] "Coalescence" in the sense of the present invention means that the boundaries between two droplets disappear upon contact to form a single droplet, which subsequently changes shape, resulting in a reduction in the total surface area.

[0048] A "suspension" or "slurry" within the meaning of the present invention comprises insoluble solids and a liquid medium such as water, and optionally further additives, and generally contains a large amount of solids and is therefore more viscous and has a higher density than the liquid from which it is formed.

[0049] According to the present invention, the term "solid" refers to a material that is solid at standard ambient temperature and pressure (SATP, which refers to 298.15 K (25° C.) and an absolute pressure of exactly 1 bar). The solid may be in the form of a powder, tablet, granule, flake, etc. Thus, the term "liquid medium" refers to a material that is liquid at standard ambient temperature and pressure (SATP, which refers to 298.15 K (25° C.) and an absolute pressure of exactly 1 bar).

[0050] When the term "comprising" is used in this description and claims, it does not exclude other elements of major or minor functional importance that are not specified. For the purposes of the present invention, the term "consisting of" is considered to be a preferred embodiment of the term "comprising". If a group is defined below as comprising at least a certain number of embodiments, this is also understood to disclose such a group, which preferably consists only of these embodiments.

[0051] Whenever the terms "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above.

[0052] Where an indefinite or definite article is used when referring to a singular noun eg "a", "an" or "the", this includes a plural of that noun unless something else is specifically stated.

[0053] Terms such as "capable of obtaining" or "capable of being defined" and "obtained" or "defined" are used interchangeably. Unless the context clearly indicates otherwise, for example, the term "obtained" is not meant to indicate that, for example, an embodiment must be obtained, for example, by the sequence of steps corresponding to the term "obtained", but such a limited understanding is always included by the term "obtained" or "defined" as a preferred embodiment.

[0054] As described above, the present invention relates to a Pickering emulsion comprising:

[0055] (i) water;

[0056] (ii) 10-50 wt% of oil, based on the total weight of the Pickering emulsion, and

[0057] (iii) 1 to 10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion,

[0058] wherein the Pickering pigment is calcium carbonate particles selected from surface reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface reacted calcium carbonate (SRCC), and

[0059] The calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0060] The details and preferred embodiments of the Pickering emulsion will be described in more detail below. It is to be understood that these embodiments or details also apply to the composition of the present invention, the method for preparing the Pickering emulsion and the use of the calcium carbonate particles of the present invention.

[0061] (i)Water

[0062] According to the present invention, water is present in the Pickering emulsion.

[0063] The water of the present invention can be selected from drinking water, process water, softened water, distilled water, rainwater, recycled water, river water and mixtures thereof. According to a preferred embodiment of the present invention, the water present in the Pickering emulsion is drinking water, softened water or distilled water, preferably softened water.

[0064] Drinking water, also known as potable water, is water that is safe for drinking or use in food preparation. Rainwater / river water is obtained from rain / rivers. Recycled water is water that has been recycled and can be used in agriculture. Process water is water that is considered non-potable and is primarily used in industrial facilities, industrial processes, and production equipment. Softened water is specially purified water that has had most or all of its minerals and salt ions, such as calcium, magnesium, sodium, chloride, sulfate, nitrate, and bicarbonate, removed. It is also called deionized water. Distilled water is water that has been boiled to vapor and condensed back into a liquid in a separate container.

[0065] According to one embodiment of the present invention, water is present in the Pickering emulsion in an amount of 11-80 wt % based on the total weight of the Pickering emulsion, preferably in an amount of 20-80 wt % based on the total weight of the Pickering emulsion, even more preferably in an amount of 30-70 wt %, and most preferably in an amount of 40-60 wt %.

[0066] (ii) Oil

[0067] According to the present invention, the oil is present in the Pickering emulsion.

[0068] Oil is liquid at 25°C and 1.0 bar and does not form a homogeneous mixture when mixed with water.

[0069] The oil is present in the Pickering emulsion in an amount of 10-50 wt% oil based on the total weight of the Pickering emulsion. According to a preferred embodiment of the present invention, the Pickering emulsion comprises 10-40 wt% oil, preferably 10-30 wt% oil, most preferably 10-20 wt% oil, based on the total weight of the Pickering emulsion.

[0070] The oil:water ratio in the Pickering emulsion may be from 100:600 to 100:20, preferably from 100:400 to 100:40, more preferably from 100:200 to 100:60, most preferably from 100:150 to 100:80, based on the weight of water and oil.

[0071] In one embodiment of the present invention, the Pickering emulsion contains only one oil. Alternatively, the Pickering emulsion contains two or more different oils. For example, the Pickering emulsion contains two or three different oils. If the Pickering emulsion contains more than one oil, the different oils may be miscible or immiscible, but are preferably miscible.

[0072] The oil may be any oil known to those skilled in the art to be suitable for a particular application. Such oils are commercially available.

[0073] According to one embodiment of the invention, the oil is selected from mineral oils, vegetable oils, animal fats, essential oils and mixtures thereof.

[0074] "Mineral oil" within the meaning of the present invention is a colorless, odorless, light mixture of higher alkanes and / or cycloalkanes of mineral origin, in particular petroleum distillates. Its density is about 0.8-0.87 g / cm 3 Mineral oil is also known as white oil, paraffin oil, liquid paraffin, petrolatum, and liquid petroleum. Mineral oil is a liquid by-product of refining crude oil to make gasoline and other petroleum products. Mineral oil is known to those skilled in the art and is commercially available.

[0075] "Vegetable oils", also known as vegetable fats, are oils extracted from seeds or other parts of fruits within the meaning of the present invention. Vegetable fats are primarily mixtures of triglycerides. Vegetable oils are generally edible. Vegetable oils are known to those skilled in the art and are commercially available. Commonly used vegetable oils are, for example, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil, avocado oil, babassu oil, rice bran oil or castor oil.

[0076] "Animal fat," also known as animal oil, is a lipid material derived from animals within the meaning of the present invention and often contains triglycerides. Although many animal parts and secretions can produce oil, in commercial practice, oil is primarily extracted from discarded tissue fat obtained from livestock animals. However, dairy products also produce commonly used animal fat and oil products such as cheese, butter, and milk. Animal oils are known to those skilled in the art and are commercially available. Commonly used animal oils are, for example, fish oil, lard, mink oil, or cod liver oil.

[0077] "Essential oils," also known as volatile oils, ethereal oils, or volatile oils, are concentrated, hydrophobic liquids containing volatile compounds from plants within the meaning of the present invention. Essential oils contain the "essence" of the plant's aroma, which is the characteristic fragrance of the plant from which they originate. Essential oils are typically extracted by distillation, often using steam. Essential oils are known to those skilled in the art and are commercially available. Commonly used essential oils are, for example, orange oil, peppermint oil, rose oil, neem oil, lavender oil, lemon oil, rosemary oil, pine oil, tea tree oil, clove oil, or jasmine oil.

[0078] According to a preferred embodiment of the present invention, the oil is selected from essential oils, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil and mixtures thereof, preferably selected from sunflower oil, olive oil, palm oil and / or coconut oil, most preferably sunflower oil.

[0079] Additionally or alternatively, the oil is a refined oil. Refined oil in the sense of the present invention is an oil obtained from a "cleaning" process, which may include degumming, neutralization, bleaching and / or deodorizing these oils. Such cleaning methods are well known to those skilled in the art and, depending on the oil and subsequent applications, are well known to those skilled in the art. The acid number of the refined oil is lower than 0.6, preferably lower than 0.5, most preferably lower than 0.3.

[0080] However, the oil may also be an unrefined oil having an acid number below 4.0, preferably below 3.0, most preferably below 2.0.

[0081] "Acid value," also known as "neutralization number," "acid value," or "acidity," is the mass (in milligrams) of potassium hydroxide (KOH) required to neutralize 1 gram of a chemical, such as an oil. Acid value is a measure of the number of carboxylic acid groups in a compound, such as an oil. Those skilled in the art know how to measure acid value.

[0082] According to one embodiment of the present invention, the oil is selected from mineral oils, vegetable oils, animal fats, essential oils and mixtures thereof, preferably selected from essential oils, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil and mixtures thereof, preferably selected from sunflower oil, olive oil, palm oil and / or coconut oil, most preferably sunflower oil, and is a refined oil having an acid value of less than 0.6, preferably less than 0.5, most preferably less than 0.3, or an unrefined oil having an acid value of less than 4.0, preferably less than 3.0, most preferably less than 2.0.

[0083] According to an exemplary embodiment of the present invention, the oil is a vegetable oil, preferably sunflower oil. Sunflower oil is commercially available, for example from M-classic.

[0084] (iii) Pickering pigments

[0085] According to the present invention, the Pickering emulsion comprises a Pickering pigment.

[0086] As mentioned above, "Pickering pigments" within the meaning of the present invention are pigments which aggregate at the oil / water boundary surfaces of the droplets in the Pickering emulsion and stabilize them.

[0087] The Pickering pigment of the present invention is a calcium carbonate particle selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), wherein the calcium carbonate particle has a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0088] According to one embodiment of the present invention, the ground calcium carbonate in the Pickering emulsion is selected from marble, limestone and / or chalk, preferably marble; and / or the surface-reacted calcium carbonate in the Pickering emulsion is natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + The ion donor process is formed in situ and / or supplied from an external source.

[0089] Surface-reacted calcium carbonate

[0090] H3O + Ion donors in the context of the present invention are Brønsted acids and / or acid salts.

[0091] In a preferred embodiment of the present invention, the surface-reacted calcium carbonate is obtained by a method comprising the following steps: (a) providing a suspension of natural or precipitated calcium carbonate, (b) aA value of 0 or less or a pK value at 20°C a at least one acid having a pK value of 0 to 2.5 is added to the suspension of step (a), and (c) the suspension of step (a) is treated with carbon dioxide before, during or after step (b). According to another embodiment, the surface-reacted calcium carbonate is obtained by a process comprising the steps of: (A) providing natural or precipitated calcium carbonate, (B) providing at least one water-soluble acid, (C) providing gaseous CO2, (D) contacting the natural or precipitated calcium carbonate of step (A) with the at least one acid of step (B) and the CO2 of step (C), characterized in that: (i) the at least one acid of step B) has a pK value of 0 to 2.5 at 20°C. a greater than 2.5 and less than or equal to 7, which is associated with the ionization of its first available hydrogen, and the corresponding anion formed by the loss of the first available hydrogen, which is capable of forming a water-soluble calcium salt, and (ii) upon contacting the at least one acid with the natural or precipitated calcium carbonate, additionally providing at least one water-soluble salt, which, in the case of a hydrogen-containing salt, has a pKa at 20° C. greater than 7, which is associated with the ionization of the first available hydrogen, and the formation of a salt anion of a water-insoluble calcium salt.

[0092] The "natural ground calcium carbonate" (GCC) used to prepare the surface-reacted calcium carbonate is preferably selected from minerals containing calcium carbonate, which are selected from marble, chalk, limestone and mixtures thereof. Natural calcium carbonate may contain additional naturally occurring components such as magnesium carbonate, aluminosilicates, etc.

[0093] Typically, the grinding of natural ground calcium carbonate can be a dry or wet grinding step, and can be carried out with any conventional grinding device, such as under conditions where the crushing is primarily carried out using the impact of secondary bodies, i.e. one or more of the following: ball mill, rod mill, vibrating mill, roller crusher, centrifugal impact mill, vertical bead mill, attritor, pin mill, hammer mill, pulverizer, shredder, deblocker, knife cutter or other such devices known to those skilled in the art. In the case where the mineral material comprising calcium carbonate comprises a mineral material comprising wet ground calcium carbonate, the grinding step can be carried out under conditions where autogenous grinding occurs and / or by a horizontal ball mill, and / or other such methods known to those skilled in the art. The mineral material thus obtained comprising wet-processed ground calcium carbonate can be cleaned and dehydrated with known methods such as flocculation, filtration or forced evaporation before drying. The step after drying (if necessary) can be carried out in a single step such as spray drying, or in at least two steps. Typically, this mineral material can also be subjected to a beneficiation step (such as flotation, bleaching or magnetic separation step) to remove impurities.

[0094] " precipitated calcium carbonate " (PCC) for the preparation of surface-reacted calcium carbonate is a kind of synthetic material in the implication of the present invention, usually by carbonic acid gas and calcium hydroxide reaction after precipitation in aqueous environment, or by calcium and carbonate ion such as CaCl and Na CO From solution, be precipitated out and obtain.The other possible mode of producing PCC is the lime soda process, or PCC is the ammonia-soda process (Solvay process) of the by-product of production ammonia.Precipitated calcium carbonate exists with three kinds of main crystalline forms: calcite, aragonite and vaterite, and for each of these crystalline forms, there are many different polymorphs (crystal habit).Calcite has triangular structure, has typical crystal habit such as scalenohedron (S-PCC), rhombohedron (R-PCC), six prism, axial plane, colloid (C-PCC), cube and prism (P-PCC). Aragonite has an orthorhombic crystal structure with the typical crystal habit of double hexagonal prisms, as well as variations such as thin elongated prisms, curved lobes, steep pyramids, chisel-shaped crystals, branching trees, and coral or worm-like forms. Vaterite belongs to the hexagonal crystal system. The resulting PCC slurry can be mechanically dehydrated and dried.

[0095] According to one embodiment of the present invention, the precipitated calcium carbonate is a precipitated calcium carbonate, preferably comprising aragonite, vaterite or calcite mineralogical crystal forms or mixtures thereof.

[0096] Precipitated calcium carbonate using carbon dioxide and at least one H3O + Prior to ion donor treatment, grinding may be performed by the same means as described above for grinding natural calcium carbonate.

[0097] According to one embodiment of the present invention, the natural or precipitated calcium carbonate used to prepare the surface-reacted calcium carbonate is a calcium carbonate having a weight median particle size d 50 In the form of particles having a particle size of 0.05-10.0 μm, preferably 0.2-5.0 μm, more preferably 0.4-3.0 μm, most preferably 0.6-1.2 μm, in particular 0.7 μm. According to another embodiment of the present invention, the natural or precipitated calcium carbonate used to prepare the surface-reacted calcium carbonate is a top cut particle size d 98 The granules are in the form of particles (wt%) of 0.15-55 μm, preferably 1-40 μm, more preferably 2-25 μm, most preferably 3-15 μm, especially 4 μm.

[0098] Natural and / or precipitated calcium carbonate can be used dry or suspended in water. Preferably, the corresponding slurry has a content of natural or precipitated calcium carbonate of 1 wt% to 90 wt%, more preferably 3 wt% to 60 wt%, even more preferably 5 wt% to 40 wt%, most preferably 10 wt% to 25 wt%, based on the weight of the slurry.

[0099] One or more H3O for preparing surface-reacted calcium carbonate+ The ion donor can be any strong, medium or weak acid or mixture thereof, which under the preparation conditions produces H3O + According to the present invention, at least one H3O + The ion donor can also be an acid salt, which produces H3O under the preparation conditions. + ion.

[0100] According to one embodiment, at least one H3O + The ion donor has a pK of a A strong acid with a concentration of 0 or less.

[0101] According to another embodiment, at least one H3O + The ion donor has a pK of a A medium strong acid with a pKa of 0 to 2.5. If the pKa at 20°C is 0 or less, the acid is preferably selected from sulfuric acid, hydrochloric acid or a mixture thereof. a is 0-2.5, then H3O + The ion donor is preferably selected from H2SO3, H3PO4, oxalic acid or a mixture thereof. + The ion donor can also be an acid salt, for example with the corresponding cation such as Li + 、Na + or K + At least partially neutralized HSO4 - or H2PO4 - , or with corresponding cations such as Li + 、Na + , K + Mg 2+ or Ca 2+ At least partially neutralized HPO4 2- At least one H3O + The ion donor may also be a mixture of one or more acids and one or more acid salts.

[0102] According to yet another embodiment, at least one H3O + The ion donor has a pK value measured at 20°C. a A weak acid having a pK value greater than 2.5 and less than or equal to 7, which is associated with the ionization of the first available hydrogen and has a corresponding anion capable of forming a water-soluble calcium salt. Subsequently, at least one water-soluble salt is additionally provided, which in the case of a hydrogen-containing salt has a pK measured at 20°C. a Greater than 7, which is associated with the ionization of the first available hydrogen and the formation of a water-insoluble calcium salt anion. According to this preferred embodiment, the pK of the weak acid at 20°C is aThe value is greater than 2.5-5, and more preferably the weak acid is selected from acetic acid, formic acid, propionic acid and mixtures thereof. Exemplary cations of the water-soluble salt are selected from potassium, sodium, lithium and mixtures thereof. In a more preferred embodiment, the cation is sodium or potassium. Exemplary anions of the water-soluble salt are selected from phosphate, dihydrogen phosphate, monohydrogen phosphate, oxalate, silicate, mixtures thereof and hydrates thereof. In a more preferred embodiment, the anion is selected from phosphate, dihydrogen phosphate, monohydrogen phosphate, mixtures thereof and hydrates thereof. In a most preferred embodiment, the anion is selected from dihydrogen phosphate, monohydrogen phosphate, mixtures thereof and hydrates thereof. The addition of the water-soluble salt can be carried out dropwise or in a single step. In the case of dropwise addition, the addition is preferably carried out over a period of 10 minutes. More preferably, the salt is added in a single step.

[0103] According to one embodiment of the present invention, at least one H3O + The ion donor is selected from hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, citric acid, oxalic acid, acetic acid, formic acid and mixtures thereof. Preferably, at least one H3O + The ion donor is selected from the group consisting of the corresponding cations such as Li + 、Na + or K + At least partially neutralized hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid, H2PO4 - , with corresponding cations such as Li + 、Na + , K + Mg 2+ or Ca 2+ and mixtures thereof at least partially neutralized HPO4 2- , more preferably at least one acid selected from hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, oxalic acid or a mixture thereof, most preferably at least one H3O + The ion donor is phosphoric acid.

[0104] One or more H3O + The ion donor can be added to the suspension as a concentrated solution or a more dilute solution. Preferably, H3O + The molar ratio of ion donor to natural or precipitated calcium carbonate is 0.01-4, more preferably 0.02-2, even more preferably 0.05-1, and most preferably 0.1-0.58.

[0105] As an alternative, H3O can be added before suspending natural or precipitated calcium carbonate. + Ion donors are added to the water.

[0106] In the next step, the natural or precipitated calcium carbonate is treated with carbon dioxide. If a strong acid such as sulfuric acid or hydrochloric acid is used to treat the natural or precipitated calcium carbonate, then the H3O +Alternatively or additionally, carbon dioxide may be supplied from an external source.

[0107] H3O + The ion donor treatment and the treatment with carbon dioxide can be carried out simultaneously, which is the case when using strong or medium-strong acids. It is also possible to first carry out the H3O + Ion donor treatment, for example, with a pK at 20°C a The carbon dioxide is formed in situ, so the carbon dioxide treatment will automatically react with H3O. + Ion donor treatment was performed simultaneously, followed by additional treatment with carbon dioxide provided by an external source.

[0108] In a preferred embodiment, H3O + The ion donor treatment step and / or the carbon dioxide treatment step are repeated at least once, more preferably several times. + The ion donor is added over a period of at least about 5 minutes, preferably at least about 10 minutes, typically about 10 to about 20 minutes, more preferably about 30 minutes, even more preferably about 45 minutes, and sometimes about 1 hour or more.

[0109] In H3O + After the ion donor treatment and the carbon dioxide treatment, the pH of the aqueous suspension measured at 20°C naturally reaches a value of greater than 6.0, preferably greater than 6.5, more preferably greater than 7.0, even more preferably greater than 7.5, thereby preparing the surface-reacted natural or precipitated calcium carbonate as an aqueous suspension having a pH greater than 6.0, preferably greater than 6.5, more preferably greater than 7.0, even more preferably greater than 7.5.

[0110] Further details on the preparation of surface-reacted natural calcium carbonate are disclosed in WO0039222A1, WO2004083316A1, WO2005121257A2, WO2009074492A1, EP2264108A1, EP2264109A1 and US20040020410A1, the contents of these references are hereby included in the present application.

[0111] Similarly, surface reaction precipitated calcium carbonate is obtained. As details can be obtained from WO2009074492A1, surface reaction precipitated calcium carbonate is obtained as follows: precipitated calcium carbonate is reacted with H3O + ions and anions which are dissolved in the aqueous medium and capable of forming a water-insoluble calcium salt are contacted in an aqueous medium to form a slurry of surface-reacted precipitated calcium carbonate, wherein the surface-reacted precipitated calcium carbonate comprises an insoluble, at least partially crystalline calcium salt of the anion formed on at least a portion of the surface of the precipitated calcium carbonate.

[0112] The dissolved calcium ions correspond to the amount of calcium ions dissolved by H3O relative to the amount of calcium carbonate precipitated. + Ion dissolution naturally produces excess dissolved calcium ions, where the H3O + The ion is provided solely as a counterion to the anion, ie, via addition of an acid or a non-calcium acid salt of the anion, and in the absence of any additional calcium ions or sources of calcium ion generation.

[0113] The excess dissolved calcium ions are preferably provided by the addition of a soluble neutral or acidic calcium salt, or by the addition of an acid or a neutral or acidic non-calcium salt which generates a soluble neutral or acidic calcium salt in situ.

[0114] The H3O + Ions may be provided by adding an acid or acid salt of the anion, or by adding an acid or acid salt that simultaneously provides all or part of the excess dissolved calcium ions.

[0115] In another preferred embodiment of the preparation of surface-reacted natural or precipitated calcium carbonate, natural or precipitated calcium carbonate is reacted with one or more H3O + The ion donor and / or carbon dioxide are reacted in the presence of at least one compound selected from silicates, silicon dioxide, aluminum hydroxide, alkaline earth metal aluminates such as sodium aluminate or potassium aluminate, magnesium oxide or mixtures thereof. Preferably, the at least one silicate is selected from aluminum silicate, calcium silicate or alkaline earth metal silicate. + Before the ion donor and / or carbon dioxide are added, these components may be added to the aqueous suspension comprising natural or precipitated calcium carbonate.

[0116] Alternatively, natural or precipitated calcium carbonate is mixed with one or more H3O + Once the reaction of the ion donor and carbon dioxide has begun, a silicate and / or silicon dioxide and / or aluminum hydroxide and / or alkaline earth metal aluminate and / or magnesium oxide component can be added to the aqueous suspension of natural or precipitated calcium carbonate. Further details on the preparation of surface-reacted natural or precipitated calcium carbonate in the presence of at least one silicate and / or silicon dioxide and / or aluminum hydroxide and / or alkaline earth metal aluminate component are disclosed in WO2004083316A1, the content of which is hereby incorporated into the present application.

[0117] In a particularly preferred embodiment of the present invention, the surface-reacted calcium carbonate is a mixture of natural ground calcium carbonate and carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + The ion donor is processed in situ, and wherein the one or more H3O +The ion donor is phosphoric acid.

[0118] The surface-reacted calcium carbonate can be maintained in suspension, optionally further stabilized with a dispersant. Conventional dispersants known to those skilled in the art can be used. A preferred dispersant comprises polyacrylic acid and / or carboxymethyl cellulose.

[0119] Alternatively, the above aqueous suspension may be dried, thereby obtaining solid (ie dry or containing such small amounts of water that it is not in fluid form) surface-reacted natural or precipitated calcium carbonate in the form of particles or powder.

[0120] In a preferred embodiment, the surface-reacted calcium carbonate has a 10 m 2 / g-200m 2 / g specific surface area, preferably 20m 2 / g-180m 2 / g, more preferably 25m 2 / g-140m 2 / g, most preferably 48m 2 / g-110m 2 / g. BET specific surface area is defined in the meaning of the present invention as the surface area of the particle divided by the mass of the particle. As used herein, specific surface area is measured using the adsorption of the BET isotherm (ISO 9277:2010) and is expressed in m 2 / g regulations.

[0121] It is also more preferred that the surface-reacted calcium carbonate particles have a volume median particle size d of 1.5-9 μm. 50 (wt), preferably 2.5-7.5 μm, most preferably 3.3-6.6 μm.

[0122] Furthermore, it may be preferred that the surface-reacted calcium carbonate particles have a top cut diameter d of ≤20 μm. 98 (vol), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm.

[0123] Value d x represents the diameter at which x vol% of the particles have a diameter smaller than d x This means that d 98 The value is the particle size at which 98 vol% of all particles are smaller than this particle size. 98 The value is also called "top cut particle size". x The values are given in volume percent. Therefore d 50 The (vol) value is the median particle size, ie, the particle size that is smaller than 50 vol% of all particles.

[0124] The volume median particle size was estimated using a Malvern Mastersizer 2000 Laser Diffraction System. The raw data obtained from this measurement was analyzed using Mie theory, and the particle refractive index was 1.57 and the absorption index was 0.005.

[0125] This method and instrument are known to those skilled in the art and are commonly used to determine the particle size of fillers and pigments.

[0126] The specific pore volume was measured using mercury intrusion using a Micromeritics Autopore V 9620 mercury intrusion meter (with a maximum applied mercury pressure of 414 MPa (60,000 psi), equivalent to a Laplace throat diameter of 0.004 μm (~nm)). The equilibrium time used for each pressure step was 20 seconds. The sample material was sealed in a 5 cm 3 The data were corrected for mercury compression, penetrometer expansion, and sample material compression using the software Pore-Comp (Gane, P.A.C., Kettle, J.P., Matthews, G.P., and Ridgway, C.J., "Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations," Industrial and Engineering Chemistry Research, 35(5), 1996, pp. 1753-1764).

[0127] The total pore volume observed in the cumulative indentation data can be divided into two regions. The indentation data from 214 μm down to approximately 1-4 μm shows the sample's coarse packing within any firmly constructed aggregate structure. Below these diameters, the fine interparticle packing within the particles themselves is smaller. If they also have intraparticle pores, this region exhibits bimodality, and the specific intraparticle pore volume is defined by the specific pore volume of mercury indented pores finer than the modal inflection point, i.e., the bimodal inflection point. The sum of these three regions gives the total overall pore volume of the powder, but this is primarily determined by initial sample compaction / powder settling at the coarse-pore end of the distribution.

[0128] By taking the first derivative of the cumulative intrusion curve, the pore size distribution based on the equivalent Laplace diameter is revealed, which inevitably includes pore obscuration. The differential curve clearly shows the coarse aggregate pore structure region, the interparticle pore region, and the intraparticle pore region, if present. Knowing the intraparticle pore diameter range, the remaining interparticle and interaggregate pore volume can be subtracted from the total pore volume to obtain the desired pore volume of the internal pores only, which is expressed as pore volume / unit mass (specific pore volume). The same subtraction principle can of course be applied to isolate any other pore size region of interest.

[0129] Preferably, the surface-reacted calcium carbonate has a surface area of 0.1-2.3 cm2 as calculated by mercury intrusion porosimetry. 3 / g of the particle internal pressure-injection specific pore volume, more preferably 0.2-2.0cm 3 / g, particularly preferably 0.4-1.5cm 3 / g, most preferably 0.6-1.1cm 3 / g.

[0130] The particle internal pore size of the surface-reacted calcium carbonate as determined by mercury intrusion porosimetry is preferably 0.004-1.6 μm, more preferably 0.005-1.3 μm, particularly preferably 0.006-1.15 μm, and most preferably 0.007-1.0 μm.

[0131] According to one embodiment of the present invention, the surface-reacted calcium carbonate has:

[0132] a) Volume median particle size d of 1.5 μm to 9.0 μm 50 value, preferably 2.5 μm to 7.5 μm, most preferably 3.3 μm to 6.6 μm, and

[0133] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, and

[0134] c) 10-200 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 20-180m 2 / g, more preferably 25-140m 2 / g, most preferably 48-110m 2 / g, and

[0135] d) 0.1-2.3 cm calculated by mercury intrusion method 3 / g of the particle internal pressure-injection specific pore volume, more preferably 0.2-2.0cm 3 / g, particularly preferably 0.4-1.5cm 3 / g, most preferably 0.6-1.1cm3 / g.

[0136] According to another embodiment of the present invention, the surface-reacted calcium carbonate has:

[0137] a) Volume median particle size d of 1.5 μm to 9.0 μm 50 Value, preferably 2.5μm-7.5μm, most preferably 3.3μm-6.6μm, or

[0138] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, or

[0139] c) 10-200 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 20-180m 2 / g, more preferably 25-140m 2 / g, most preferably 48-110m 2 / g, or

[0140] d) 0.1-2.3 cm calculated by mercury intrusion method 3 / g of the particle internal pressure-injection specific pore volume, more preferably 0.2-2.0cm 3 / g, particularly preferably 0.4-1.5cm 3 / g, most preferably 0.6-1.1cm 3 / g.

[0141] According to an exemplary embodiment of the present invention, the Pickering pigment of the present invention is a surface-reacted calcium carbonate particle having a 10 m 2 / g-200m 2 / g specific surface area, preferably 20m 2 / g-180m 2 / g, more preferably 25m 2 / g-140m 2 / g, for example 40m 2 / g-70m 2 Additionally or alternatively, the surface-reacted calcium carbonate particles have a volume median particle size d of 1.5 μm to 9.0 μm. 50 According to a preferred embodiment of the present invention, the Pickering pigment is a surface-reacted calcium carbonate particle having a particle diameter of 40 μm as measured using nitrogen and the BET method. 2 / g-70m 2 / g specific surface area, and a volume median particle size of 5.0μm-8.0μm 50 value.

[0142] Ground calcium carbonate

[0143] According to a preferred embodiment of the present invention, the ground calcium carbonate is selected from marble, limestone and / or chalk, preferably marble.

[0144] As mentioned above, GCC is understood to be a naturally occurring form of calcium carbonate, mined from sedimentary rocks such as limestone or chalk, or from metamorphic marble, and processed by wet and / or dry treatments such as grinding, screening and / or classification, for example by cyclones or classifiers.

[0145] The ground calcium carbonate is preferably in the form of a particulate material and preferably has a volume median particle size d of 0.3 μm to 5.0 μm. 50 value, preferably 0.6μm-3μm, most preferably higher than 1.0μm-1.7μm.

[0146] Additionally or alternatively, the ground calcium carbonate has a top cut particle size (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm.

[0147] Additionally or alternatively, the ground calcium carbonate has a microstructure of 0.5-50 m³ as measured by the BET nitrogen method. 2 For example, at least one calcium carbonate has a BET surface area of 0.5 to 35 m / g as measured by the BET nitrogen method. 2 / g specific surface area (BET), more preferably 0.5-25m 2 / g, most preferably 0.6-17m 2 / g.

[0148] According to one embodiment of the present invention, the ground calcium carbonate has:

[0149] a) Volume median particle size d of 0.3 μm to 5.0 μm 50 Value, preferably 0.6μm-3μm, most preferably higher than 1.0μm-1.7μm, and

[0150] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, and

[0151] c) 0.5-50 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 0.5-35m 2 / g, more preferably 0.5-25m 2 / g, most preferably 0.6-17m 2 / g.

[0152] According to another embodiment of the present invention, the ground calcium carbonate has:

[0153] a) Volume median particle size d of 0.3 μm to 5.0 μm 50 Value, preferably 0.6μm-3μm, most preferably higher than 1.0μm-1.7μm, or

[0154] b) Top cut particle size ≤ 20 μm (d 98 (vol)), preferably ≤15 μm, more preferably ≤10 μm, most preferably ≤7 μm, or

[0155] c) 0.5-50 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), preferably 0.5-35m 2 / g, more preferably 0.5-25m 2 / g, most preferably 0.6-17m 2 / g.

[0156] Ground calcium carbonate (GCC) can be added as a dry material or can be added in a wet form, such as a slurry. Preferably, the ground calcium carbonate is a dry ground material, a wet ground and dried material, or a mixture of the foregoing materials. Typically, the grinding step can be carried out with any conventional grinding device, such as under conditions where the impact of the crushing is primarily used as a secondary body, i.e., one or more of the following: a ball mill, a rod mill, a vibrating mill, a roller mill, a centrifugal impact mill, a vertical bead mill, an attritor, a pin mill, a hammer mill, a pulverizer, a shredder, a deblocker, a knife cutter, or other such devices known to those skilled in the art.

[0157] In the case where the ground calcium carbonate is wet ground calcium carbonate, the grinding step can be carried out under conditions where autogenous grinding occurs and / or by a horizontal ball mill, and / or other such methods known to those skilled in the art. The wet-processed ground calcium carbonate thus obtained can be cleaned and dehydrated with known methods such as flocculation, filtration or forced evaporation before drying. The step after drying can be carried out in a single step such as spray drying, or in at least two steps, such as applying a first heating step to the calcium carbonate to reduce the relevant moisture content to a level not greater than about 1 wt % based on the total dry weight of the calcium carbonate. The residual total moisture content of the filler can be measured by Karl Fischer coulometric titration, desorbing moisture in a 195° C. oven and continuously feeding it to a KF coulometer (Mettler Toledo coulometric KF titrator C30, combined with a Mettler oven DO 0337) using 100 ml / min of dry N 2 over 10 min. The residual total moisture content can be measured using a calibration curve, and a blank control of a 10 min airflow without a sample can also be considered. The residual total moisture content can be further reduced by subjecting the calcium carbonate to a second heating step. In the case where the drying is carried out by more than one drying step, the first step can be carried out by heating in a hot air stream, while the second and further drying steps are preferably carried out by indirect heating, wherein the atmosphere in the respective container contains a surface treatment agent. The calcium carbonate can also typically be subjected to a beneficiation step (e.g., flotation, bleaching, or magnetic separation step) to remove impurities.

[0158] In one embodiment of the present invention, the ground calcium carbonate comprises dry ground calcium carbonate.In another preferred embodiment, the ground calcium carbonate is a material that is wet ground in a horizontal ball mill and subsequently dried using a well-known spray drying method.

[0159] The ground calcium carbonate may comprise one or more, such as two or three, calcium carbonates. According to a preferred embodiment, the ground calcium carbonate comprises only one calcium carbonate, preferably marble.

[0160] According to one embodiment of the present invention, the Pickering pigment, preferably the surface-reacted calcium carbonate particles, is not coated with a surface treatment agent. According to a preferred embodiment, the Pickering pigment of the present invention is not surface-treated with: fatty acid esters such as glyceryl monostearate, PEG 7 cocoyl glyceryl, glycol stearate or glycol distearate, lecithin, fractionated lecithin, hydrogenated lecithin, surfactants such as sodium cocoyl glycinate, castor oil derivatives such as 12-hydroxystearic acid or hydrogenated castor oil, fatty alcohols such as acetyl alcohol, oxyoctyl alcohol, stearyl alcohol or behenyl alcohol or saturated or unsaturated fatty acids such as myristic acid, palmitic acid, stearic acid or oleic acid or their salts, compounds containing mono- or di-substituted succinic anhydrides, compounds containing mono- or di-substituted succinic acids, compounds containing mono- or di-substituted succinates, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; mixtures thereof and reaction products thereof.

[0161] The Pickering pigment is present in the Pickering emulsion in an amount of 1-10 wt % based on the total weight of the Pickering emulsion. According to a preferred embodiment, the Pickering emulsion comprises 2-10 wt % of Pickering pigment, preferably 4-10 wt % of Pickering pigment, and most preferably 6-10 wt % of Pickering pigment, based on the total weight of the Pickering emulsion.

[0162] Pickering pigments are calcium carbonate particles selected from surface reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface reacted calcium carbonate (SRCC).According to a preferred embodiment of the present invention, the Pickering pigments contain only surface reacted calcium carbonate (SRCC).

[0163] Alternatively, the Pickering pigment comprises a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC). In this case, the ratio of GCC:SRCC is 1:100 to 100:100, preferably 10:100 to 90:100, more preferably 30:100 to 80:100, most preferably 50:100 to 70:100, based on the dry weight of GCC and SRCC.

[0164] According to an exemplary embodiment of the present invention, the Pickering pigment comprises, preferably consists of, surface-reacted calcium carbonate particles. Preferably, the surface-reacted calcium carbonate particles have a 40 m 2 / g-70m 2 / g specific surface area, and a volume median particle size of 5.0μm-8.0μm50 value.

[0165] The Pickering emulsion of the present invention can be an oil-in-water emulsion or a water-in-oil emulsion. An oil-in-water Pickering emulsion is an emulsion in which oil droplets are stabilized in water by a Pickering pigment. A water-in-oil Pickering emulsion is an emulsion in which water droplets are stabilized in oil by a Pickering pigment. According to a preferred embodiment of the present invention, the Pickering emulsion of the present invention is an oil-in-water emulsion.

[0166] According to an exemplary embodiment of the present invention, the Pickering emulsion comprises: (i) water, (ii) 10-50 wt% of oil, based on the total weight of the Pickering emulsion, preferably selected from essential oils, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil and mixtures thereof, more preferably selected from sunflower oil, olive oil, palm oil and / or coconut oil, most preferably sunflower oil, and

[0167] (iii) 1 to 10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion,

[0168] wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), preferably surface-reacted calcium carbonate particles (SRCC), and

[0169] The calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm. 50 According to a preferred embodiment, the water in the Pickering emulsion is demineralized water.

[0170] According to another exemplary embodiment of the present invention, the Pickering emulsion comprises: (i) water, preferably demineralized water, (ii) 10-50 wt% of oil, preferably sunflower oil, based on the total weight of the Pickering emulsion, and

[0171] (iii) 1 to 10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion,

[0172] wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), preferably surface-reacted calcium carbonate particles (SRCC), and

[0173] The calcium carbonate particles have a volume median particle size d of 0.2 μm to 10 μm.50 value.

[0174] According to another exemplary embodiment of the present invention, the Pickering emulsion comprises: (i) water, preferably demineralized water, (ii) 10-50 wt% of oil, preferably sunflower oil, based on the total weight of the Pickering emulsion, and

[0175] (iii) 1 to 10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion,

[0176] wherein the Pickering pigment is surface-reacted calcium carbonate particles (SRCC), and

[0177] The calcium carbonate particles have a volume median particle size d of 1.5 μm to 9 μm. 50 Values and 10-200m measured by BET nitrogen method 2 / g specific surface area (BET), preferably 20-180m 2 / g, more preferably 25-140m 2 / g, for example 40-70m 2 / g.

[0178] Additional embodiments

[0179] According to one embodiment of the present invention, the emulsion comprises an additional active ingredient, preferably selected from cosmetically active compounds, pharmaceutically active compounds, nutritional additives, flavorings, and mixtures thereof. Such compounds are known to those skilled in the art and are commercially available. Those skilled in the art can select such compounds based on the oil used and the intended use of the Pickering emulsion.

[0180] A "cosmetic active compound" within the meaning of the present invention is an active ingredient of a cosmetic product and has at least some positive or beneficial effect on the skin or hair. Cosmetic active agents are known to those skilled in the art and are commercially available. A person skilled in the art can select such a compound depending on the oil used and the intended use of the Pickering emulsion. Known cosmetic active agents are, for example, hyaluronic acid, vitamin E, vitamin C, kojic acid, AHA, BHA, hydroquinone, vitamin A / retinoids, salicylic acid, benzoyl peroxide, azelaic acid or sulfur.

[0181] "Pharmaceutical active agents" within the meaning of the present invention are ingredients of biologically active pharmaceutical products. Pharmaceutical active agents are known to those skilled in the art and are commercially available. A person skilled in the art can select such agents based on the oil used and the intended use of the Pickering emulsion. Known pharmaceutical active agents are, for example, vitamin A, vitamin D, vitamin C, polyphenols, caffeine, flavonoids, carotenoids, isoflavones or sterols.

[0182] "Nutritional additives" in the context of the present invention are additives added to food or beverages for the purpose of restoring nutrients lost or degraded during production, enhancing or enriching certain foods or beverages to correct nutritional deficiencies, or adding nutrients to food or beverage substitutes. Nutrient additives are well known to those skilled in the art and are commercially available. Those skilled in the art can select such additives based on the target use of the oil used and the Pickering emulsion. Known nutritional additives are, for example, vitamin A, vitamin D, vitamin C, vitamin B, ω-3 oils, minerals such as sodium, manganese or selenium.

[0183] "Flavoring agent" within the meaning of the present invention is an ingredient that imparts flavor or taste to a product, such as a food, a drink or a medicine. Flavoring agents are known to those skilled in the art and are commercially available. A person skilled in the art can select such compounds depending on the oil used and the intended use of the Pickering emulsion. Flavoring agents can be natural flavoring agents, nature-identical flavoring agents or synthetic flavoring agents. Known flavoring agents are, for example, matricarb, isoamyl acetate, benzaldehyde, cinnamaldehyde, ethyl propionate, methyl aminobenzoate, limonene, ethyl dedacidienoate, allyl hexanoate, ethyl maltitol or methyl salicylate.

[0184] The Pickering emulsion of the present invention has excellent stability against coalescence. "Stable against coalescence" means that the emulsion does not show an increase of more than 10% in the average droplet diameter when stored statically at 4°C to 20°C.

[0185] A "droplet," within the meaning of the present invention, is a discrete portion of a first fluid that is completely surrounded by a second fluid. It should be noted that a droplet need not be spherical but, depending on the external environment, may assume other shapes. The "mean diameter" of a population of droplets is the arithmetic mean of the droplet diameters. A person skilled in the art will be able to determine the mean diameter of a population of droplets, for example, using laser scattering or other known techniques. The droplet diameter of non-spherical droplets is the arithmetically defined mean diameter of the droplets integrated over the entire surface.

[0186] According to a preferred embodiment of the present invention, the Pickering emulsion is stable against coalescence for at least 15 days, more preferably at least 20 days, most preferably at least 30 days.

[0187] According to one embodiment of the present invention, the Pickering emulsion of the present invention has improved stability against coalescence compared to the same Pickering emulsion not comprising the Pickering pigment of the present invention.

[0188] “The same Pickering emulsion” in the sense of the present invention refers to a Pickering emulsion which consists of the same ingredients in the same amounts as the Pickering emulsion of the present invention, except that the emulsion does not contain the Pickering pigment of the present invention but a different Pickering pigment known from the prior art.

[0189] According to one embodiment of the present invention, the Pickering emulsion according to the invention contains no further emulsifiers, besides the Pickering pigments, for stabilizing the droplets in the Pickering emulsion.

[0190] As mentioned above, an "emulsifier" or "surfactant" or "surface active agent" or "surface treatment agent" is a substance that stabilizes an emulsion by increasing its kinetic stability. Emulsifiers are compounds that generally have an amphiphilic molecular structure consisting of a polar (hydrophilic) and a non-polar (lipophilic) portion of the molecule that are spatially separated from each other. Conventional emulsifiers can be divided into ionic (anionic, cationic and zwitterionic) and non-ionic types based on the hydrophilic portion of their molecules.

[0191] Emulsifiers are well known to those skilled in the art and are commercially available. For example, anionic emulsifiers well known to those skilled in the art are soaps, which are the conventional names for water-soluble sodium or potassium salts of saturated and unsaturated higher fatty acids. A known cationic emulsifier is a quaternary ammonium compound. The hydrophilic portion of the nonionic emulsifier molecule is often composed of glycerol, polyglycerol, sorbitan, carbohydrates or polyoxyethylene glycol, and is most often connected to the lipophilic portion of the molecule by ester and ether bonds. The latter is usually composed of fatty alcohols, fatty acids or only fatty acids (so-fatty acid).

[0192] By varying the structure and size of the polar and non-polar parts of the molecule, the lipophilicity and hydrophilicity of the emulsifier can be varied to a great extent. A person skilled in the art knows how to prepare and select an emulsifier according to the application.

[0193] As mentioned above, the Pickering emulsion according to the invention does not contain, in addition to the Pickering pigment, further emulsifiers for stabilizing the droplets in the Pickering emulsion. According to a preferred embodiment, the Pickering emulsion according to the invention does not contain fatty acid esters such as glyceryl monostearate, PEG 7 cocoglyceryl, glycol stearate or glycol distearate, lecithin, fractionated lecithin, hydrogenated lecithin, surfactants such as sodium cocoyl glycinate, castor oil derivatives such as 12-hydroxystearic acid or hydrogenated castor oil, fatty alcohols such as acetyl alcohol, oxyoctyl alcohol, stearyl alcohol or behenyl alcohol or saturated or unsaturated fatty acids such as myristic acid, palmitic acid, stearic acid or oleic acid or their salts, compounds containing mono- or di-substituted succinic anhydrides, compounds containing mono- or di-substituted succinic acids, compounds containing mono- or di-substituted succinates, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; mixtures thereof and reaction products thereof.

[0194] The inventors of the present invention have surprisingly found that the Pickering emulsions of the present invention have adequate or improved properties.

[0195] First, the Pickering pigment in the Pickering emulsion of the present invention has a volume median particle size d of 0.2 μm to 10 μm. 50 The present invention also provides a method for preparing nanoparticles containing nanoparticles having a primary diameter substantially below 150 nm. This method is advantageous because recent studies have shown that such small nanoparticles can be detrimental to the environment, humans, and animals, as they can enter the body through ingestion or through the skin and can relocate to various organs and tissues within the body or reside in plants. Due to their reactivity within human, animal, or plant cells, they can exhibit toxicological effects.

[0196] Furthermore, the inventors of the present invention have surprisingly found that, in addition to the Pickering pigment, the Pickering emulsion of the present invention does not require additional emulsifiers or surfactants, stabilizers, or surface coatings on the surface of the Pickering pigment to stabilize the droplets in the Pickering emulsion, so that a clean label emulsion can be produced. The addition of such emulsifiers, surfactants, stabilizers, or surface coatings is often undesirable, particularly in Pickering emulsions for agricultural use or for use on humans and animals, as such compounds may have side effects on humans or animals and may not be environmentally friendly.

[0197] The inventors have furthermore found that the Pickering emulsions according to the invention are white even when coloured, for example yellow, oils are used.

[0198] Compositions comprising Pickering emulsions

[0199] According to one embodiment of the present invention, there is provided a composition comprising the Pickering emulsion of the present invention, wherein the composition is a food composition, a cosmetic composition, a pharmaceutical composition or a nutritional formula milk powder.

[0200] The Pickering emulsions of the present invention can be used in food compositions, such as beverages and emulsions such as mayonnaise, low-fat spreads, vinaigrettes, ice cream, sauces, and soups. For example, Pickering emulsions can be used to introduce hydrophobic nutritional additives or flavorings into food or beverages. Such Pickering emulsions can encapsulate or protect sensitive and active food fats from environmental influences, such as oxidation resistance, or can be used to control the release of fragrance and flavor.

[0201] Cosmetics can benefit from the range of textures achievable with the Pickering emulsions of the present invention, as well as the possibility of incorporating cosmetic actives, such as fat-soluble bioactive materials, into the oil droplets.

[0202] In pharmaceutical compositions, Pickering emulsions can be used to protect sensitive pharmaceutical actives and to mask the unpleasant taste of some pharmaceutical actives.

[0203] The composition comprising the Pickering emulsion of the present invention can be a nutritional formula. The nutritional formula can be a complete nutritional formula that provides sufficient types and levels of macronutrients (protein, fat, and carbohydrates) and micronutrients to serve as the sole source of nutrition for the subject to whom it is administered. The nutritional formula can also provide partial nutrition to supplement the subject's existing diet.

[0204] Method for preparing Pickering emulsion

[0205] According to the present invention, a method for preparing the Pickering emulsion of the present invention is provided.

[0206] The method comprises the steps of:

[0207] A) provide water,

[0208] B) provide oil,

[0209] C) providing a Pickering pigment, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d greater than 0.1 μm to 10 μm 50 value,

[0210] D) combining the water of step A), the oil of step B), and the Pickering pigment of step C) in any order to obtain a mixture comprising 10-50 wt% of the oil based on the total weight of the mixture and 1-10 wt% of the Pickering pigment based on the total weight of the mixture, and

[0211] E) The mixture obtained in step D) is mixed to prepare a Pickering emulsion.

[0212] It will be appreciated that the process of the present invention may be carried out as a continuous process or as a batch process. Preferably, the process of the present invention is carried out as a batch process.

[0213] Further details of the invention, in particular the aforementioned steps of the method of the invention for preparing a Pickering emulsion, are mentioned below. Water, oil and Pickering pigment have been defined above.

[0214] Step D)

[0215] In step D) of the manufacturing method according to the present invention, the water of step A), the oil of step B) and the Pickering pigment of step C) are combined in any order to obtain a mixture comprising 10-50 wt% of oil based on the total weight of the mixture and 1-10 wt% of Pickering pigment based on the total weight of the mixture.

[0216] The contacting or combining of the water of step A), the oil of step B) and the Pickering pigment of step C) can be carried out by any conventional means known to those skilled in the art.

[0217] According to one embodiment of the present invention, step D) comprises the step of providing the water provided in step A) in a first step and then adding the oil provided in step B) in a subsequent step. This mixture is combined with the Pickering pigment provided in step C) by adding the liquid mixture to the Pickering pigment, or by adding the Pickering pigment to the liquid mixture. According to another embodiment of the present invention, step D) comprises the step of providing the oil provided in step B) in a first step and then adding the water provided in step A) in a subsequent step. This mixture is combined with the Pickering pigment provided in step C) by adding the liquid mixture to the Pickering pigment, or by adding the Pickering pigment to the liquid mixture.

[0218] According to another embodiment of the present invention, step D) comprises the step of providing the water provided in step A) in a first step and then adding the Pickering pigment provided in step C) in a subsequent step. The slurry is then combined with the oil provided in step B) by adding the oil to the slurry or by adding the slurry to the oil. According to another embodiment of the present invention, step D) comprises the step of providing the Pickering pigment provided in step C) in a first step and then adding the water provided in step A) in a subsequent step. The slurry is then combined with the oil provided in step B) by adding the oil to the slurry or by adding the slurry to the oil.

[0219] According to another embodiment of the present invention, step D) comprises the step of providing the oil provided in step B) in a first step and then adding the Pickering pigment provided in step C) in a subsequent step. The slurry is then combined with the water provided in step A) by adding the water to the slurry or by adding the slurry to the water. According to another embodiment of the present invention, step D) comprises the step of providing the Pickering pigment provided in step C) in a first step and then adding the oil provided in step B) in a subsequent step. The slurry is then combined with the water provided in step A) by adding the water to the slurry or by adding the slurry to the water.

[0220] According to another embodiment of the present invention, step D) comprises the step of combining the oil provided in step B) with a specified amount of the Pickering pigment provided in step C). The remaining amount of the Pickering pigment provided in step C) is combined with the water provided in step A). Thereafter, the two slurries are combined together in any order.

[0221] The Pickering pigment provided in step C) can be added to the water or oil or the mixture in one portion, or can be added in several equal or unequal portions (ie divided into large and small portions).

[0222] According to a preferred embodiment of the present invention, step D) comprises the steps of providing the oil provided in step B) in a first step and then adding the Pickering pigment provided in step C) in a subsequent step. The slurry is then combined with the water provided in step A) by adding water to the slurry or by adding the slurry to water, preferably by adding water to the slurry.

[0223] Step E)

[0224] In step E), the mixture obtained in step D) is mixed to prepare a Pickering emulsion.

[0225] As mentioned above, a Pickering emulsion within the meaning of the present invention is an emulsion in which the Pickering pigments accumulate in the form of a layer at the oil / water boundary surface, thereby preventing dispersion from binding.

[0226] Those skilled in the art know how to mix such mixtures to prepare Pickering emulsions.

[0227] The mixing in step E) can be accomplished by any conventional means known to those skilled in the art that will produce a Pickering emulsion. The skilled person will vary the mixing conditions such as mixing speed, division and temperature depending on his process setup.

[0228] For example, mixing can be carried out using a disperser / homogenizer. Apparatus that can be used for the process according to the invention are commercially available, for example under the trade name ULTRA-TURRAX from IKA, Germany, for example the ULTRA-TURRAX T10 basic model, under the trade name Ariete Homogenizer 5400 from GEA, mixers available from Silverson, for example the Ultramix or ultrasound devices available from hielscher, for example the UP200 ST.

[0229] According to another embodiment of the present invention, step e) is performed for at least 1 second, preferably at least 1 minute (e.g. 10 min, 30 min or 60 min). According to a preferred embodiment, step (c) is performed for a time period of 1 second to 60 minutes, preferably 15 min to 45 minutes. For example, mixing step (d) is performed for 30 min ± 5 min.

[0230] According to another embodiment of the present invention, step E) is carried out at room temperature, preferably at a temperature of 15-25° C. However, step E) can also be carried out at a lower or higher temperature, for example a temperature of 4° C. to 95° C., preferably a temperature of 10° C. to 70° C., most preferably a temperature of 15° C. to 40° C.

[0231] According to one embodiment of the present invention, the Pickering pigments and preferably the surface-reacted calcium carbonate particles provided in step C) are not coated with a surface treatment agent.

[0232] According to one embodiment of the present invention, the Pickering pigment, preferably the surface-reacted calcium carbonate particles, is not coated with a surface treatment agent. According to a preferred embodiment, the Pickering pigment of the present invention is not surface-treated with: fatty acid esters such as glyceryl monostearate, PEG 7 cocoyl glyceryl, glycol stearate or glycol distearate, lecithin, fractionated lecithin, hydrogenated lecithin, surfactants such as sodium cocoyl glycinate, castor oil derivatives such as 12-hydroxystearic acid or hydrogenated castor oil, fatty alcohols such as acetyl alcohol, oxyoctyl alcohol, stearyl alcohol or behenyl alcohol or saturated or unsaturated fatty acids such as myristic acid, palmitic acid, stearic acid or oleic acid or their salts, compounds containing mono- or di-substituted succinic anhydrides, compounds containing mono- or di-substituted succinic acids, compounds containing mono- or di-substituted succinates, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; mixtures thereof and reaction products thereof.

[0233] The inventors have surprisingly found that the Pickering emulsions of the present invention can be prepared by the above method. The above method is an inexpensive, particularly easy to handle method, and the Pickering emulsions of the present invention can be produced easily and quickly by the method of the present invention.

[0234] Uses of calcium carbonate granules

[0235] According to one aspect of the present invention, calcium carbonate particles are used as Pickering pigments to stabilize a Pickering emulsion comprising water and 10-50 wt % of oil, based on the total weight of the Pickering emulsion, wherein the calcium carbonate particles are selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and have a volume median particle size d of 0.2 μm to 10 μm. 50 value.

[0236] Water, oil and Pickering pigments and Pickering emulsions are as described above.

[0237] The inventors of the present invention have surprisingly found that the above-mentioned Pickering pigments can be used in Pickering emulsions.

[0238] The Pickering pigments that can be used in the Pickering emulsions of the present invention have a volume median particle size d of 0.2 μm to 10 μm. 50The nanoparticles are free of primary diameters below 150 nm, which is advantageous because recent studies have shown that such small nanoparticles can be detrimental to the environment, humans, and animals. They can enter the body during ingestion or through the skin and relocate to various organs and tissues within the body, or even within plants. Due to their reactivity within human, animal, or plant cells, they can exhibit toxicological effects.

[0239] Furthermore, the inventors of the present invention have surprisingly discovered that when using the above-mentioned Pickering pigments, the Pickering emulsions of the present invention do not require additional emulsifiers or surfactants, stabilizers, or surface coatings on the surface of the Pickering pigments in addition to the Pickering pigments to stabilize the droplets in the Pickering emulsion, so that a clean label emulsion can be produced. The addition of such emulsifiers, surfactants, stabilizers, or surface coatings is often undesirable, particularly in Pickering emulsions for agricultural use or for use on humans and animals, as such compounds may have side effects on humans or animals and may not be environmentally friendly.

[0240] The inventors have furthermore found that the Pickering pigments of the invention are white even when pigmented, for example yellow, oils are used.

[0241] The scope and focus of the present invention will be better understood based on the following examples, which are intended to illustrate certain embodiments of the invention and are not limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0242] Figure 1 :Microscope image of Pickering emulsion 2

[0243] Figure 2 :Microscope image of Pickering emulsion 3

[0244] Figure 3 : Pickering emulsion 1 Droplet size depending on storage time

[0245] experiment

[0246] 1. Measurement method

[0247] The following describes the measurement methods performed in Examples.

[0248] BET specific surface area (SSA) of the material

[0249] The BET specific surface area was determined via the BET method according to ISO 9277:2010 using nitrogen after conditioning the sample by heating for 30 minutes at 250° C. Prior to such measurement, the sample was filtered, rinsed and oven-dried at 110° C. for at least 12 hours.

[0250] Particle size distribution of particulate material (% particles, diameter <X),d 50 value (median particle size) and d 98 value:

[0251] Volume median particle size d 50 (vol) was evaluated using the Malvern Mastersizer 2000 Laser Diffraction System or the Malvern Mastersizer 3000 Laser Diffraction System. 50 (vol) or d 98 The (vol) value indicates a diameter value at which 50 vol% or 98 vol% of the particles have a diameter smaller than the value. The raw data obtained by measurement were analyzed using Mie theory, and the particle refractive index was 1.57 and the absorption index was 0.005.

[0252] This method and instrument are known to those skilled in the art and are commonly used to determine the particle size of fillers and pigments.

[0253] Gravimetric or weight-based median particle size d 50 (wt) is measured by the sedimentation method, which is the analysis of sedimentation behavior in a gravitational field. The measurement is performed using a Sedigraph from Micromeritics Instrument Corporation, USA. TM The method and instrument are known to those skilled in the art and are commonly used to determine the particle size of fillers and pigments. The measurement is carried out in a 0.1 wt% aqueous solution of Na4P2O7. The sample is dispersed using a high-speed stirrer and ultrasound.

[0254] Porosity / pore volume

[0255] Porosity or pore volume was measured using a Micromeritics Autopore IV 9500 mercury intrusion meter with a maximum applied mercury pressure of 414 MPa (60,000 psi), equivalent to a Laplace throat diameter of 0.004 μm (-nm). The equilibrium time used for each pressure step was 20 seconds. The sample material was sealed in a 5 ml chamber powder penetrometer for analysis. The data were corrected for mercury compression, penetrometer expansion, and sample material compression using the software Pore-Comp (Gane, P.A.C., Kettle, J.P., Matthews, G.P., and Ridgway, C.J., "Void Space Structure of Compressible Polymer Spheres and Consolidated Calcium Carbonate Paper-Coating Formulations," Industrial and Engineering Chemistry Research, 35(5), 1996, pp. 1753-1764).

[0256] Types of Pickering Lotions

[0257] The drop method is used to determine the emulsion type. One drop of the emulsion is placed in water, and one drop is placed in oil. In a medium with a continuous phase, the emulsion is dispersible, while in a medium with a dispersed phase, the drop settles to the container wall. This means that an O / W emulsion can be dispersed in water, but not in oil, while a W / O emulsion can only be dispersed in oil.

[0258] Droplet size (optical and light scattering)

[0259] Droplet size was determined by microscopic analysis. Images were taken at two different points on each sample (Olympus SC 50, Olympus Europa SE & Co KG, Germany) under a microscope (Olympus BX 51, Olympus Europa SE & Co KG, Germany), and 10 droplets were measured using cellSens software. The mean and standard deviation were determined from these 20 measurements.

[0260] In addition to the optical evaluation, the droplet size was also determined by light scattering (Mastersizer 3000, Malvern Panalytical GmbH, Germany). For this purpose, 2 mL of the emulsion was diluted with water and added to the wet dispersion module for measurement. This assessment was performed using the Mie theory for round particles, and the refractive index was 1.53, which is between the values for sunflower oil and calcium carbonate. Therefore, multiple refraction at the Pickering droplet (particle-drop particle) was taken into account.

[0261] The measured values determined by light scattering do not differ from the optical evaluation.

[0262] 2. Materials and Apparatus

[0263] Material

[0264] Water: Softened water

[0265] Oil: Sunflower oil, obtained from M-classic

[0266] Pickering Pigments: Surface Reacted Calcium Carbonate (SRCC) (d 50 (vol)=6.6μm,d 98 (vol)=13.7μm,SSA=59.9m 2 / g). The specific pore volume in the particles is 0.939 cm 3 / g (for pore diameters of 0.004-0.51 μm).

[0267] SRCC was obtained by preparing 350 L of an aqueous suspension of ground calcium carbonate in a mixing vessel by adjusting ground limestone calcium carbonate from Omya SAS, Orgon (with a median particle size d based on weight determined by sedimentation) to 1.5 L. 50 % solids content based on the total weight of the aqueous suspension.

[0268] While the slurry was being mixed at a speed of 6.2 m / s, 11.2 kg of phosphoric acid in the form of an aqueous solution containing 30 wt% phosphoric acid was added to the suspension over a period of 20 minutes at a temperature of 70° C. After the addition of the acid, the slurry was stirred for a further 5 minutes before it was removed from the container and dried using a jet dryer.

[0269] Ground calcium carbonate I (GCC I) (d 50 (vol)=1.0μm,SSA=3.7m 2 / g).

[0270] Ground calcium carbonate II (GCC II) (d 50(vol)=8.1μm,SSA=2.1m 2 / g).

[0271] Precipitated calcium carbonate (PCC) (d 50 (vol)=7.65μm,SSA=3.3m 2 / g).

[0272] Preparation of Pickering emulsions 1-3

[0273] Oil is added to a glass beaker. Thereafter, Pickering pigment (above-mentioned surface-reacted calcium carbonate) is added to the oil and dispersed at 5000 rpm for 1 minute using a high shear mixer (Polytron PT 3100D, Kinematica AG, Switzerland). Subsequently, water is slowly added to the slurry in 1 minute, and the mixture is homogenized at 15000 rpm for 4 minutes using a high shear mixer (Polytron PT 3100D, Kinematica AG, Switzerland).

[0274] The amounts used are given in Table 1 below.

[0275] Table 1

[0276] Oil content [g] Pigment content [g] Water content [g] Pickering Lotion 1 75 12 63 Pickering Lotion 2 15 1.5 133.5 Pickering Lotion 3 45 4.5 100.5

[0277] Preparation of emulsions 4 and 5

[0278] Emulsions 4 and 5 were prepared by the method according to Pickering emulsions 1 to 3. Ground calcium carbonate I (GCC I) was used as pigment.

[0279] Table 2

[0280] Oil content [g] Pigment content [g] Water content [g] Lotion 4 75 10.5 64.5 Lotion 5 75 15 60

[0281] Preparation of Pickering emulsion / emulsion 6-17

[0282] The oil was added to a glass beaker. Pickering pigments (SRCC) (emulsions 10, 11, 16, 17) or ground calcium carbonate II (GCC II) (emulsions 8, 9, 14, 15) or precipitated calcium carbonate (emulsions 6, 7, 12, 13) were then added to the oil and the mixture was stirred with a high shear mixer (Ultra Turrax T25, GmbH & CO. KG, Germany) at 6500 rpm for 30 seconds. Water was then slowly added to the slurry within 30 seconds, and the mixture was stirred with a high shear mixer (Ultra Turrax T25, GmbH & CO. KG, Germany) and homogenized at 17500 rpm for 2 minutes.

[0283] Oil content [g] Pigment content [g] Water content [g] Lotion 6 22.5 3.75 48.75 Lotion 7 22.5 7.5 45 Lotion 8 22.5 3.75 48.75 Lotion 9 22.5 7.5 45 Pickering Lotion 10 22.5 3.75 48.75 Pickering Lotion 11 22.5 7.5 45 Lotion 12 37.5 3.75 33.75 Lotion 13 37.5 7.5 30 Lotion 14 37.5 3.75 33.75 Lotion 15 37.5 7.5 30 Pickering Lotion 16 37.5 3.75 33.75 Pickering Lotion 17 37.5 7.5 30

[0284] In emulsions 6, 8, 9, 12, 13, 14 and 15, the oil phase and the water phase did not form an emulsion, but each phase existed separately in a mixture.

[0285] 3. Example Data

[0286] The droplet size of Pickering Emulsion 1 has been measured by light scattering on the day of preparation and after 21 days of storage at room temperature. Figure 3 It can be seen that the droplet size changes only from 17 μm to 18 μm and is therefore stable against coalescence.

[0287] The droplet sizes of Pickering emulsions 2 and 3 have been determined by microscopic analysis at room temperature on the day of preparation. Figure 1 and 2 It can be seen that the droplet size is very uniform, ranging from about 100 μm to 150 μm in Pickering emulsion 2 and from about 30 μm to 70 μm in Pickering emulsion 3.

[0288] The droplet size of emulsions 4 and 5 was determined by microscopic analysis at room temperature on the day of preparation. The droplet size was not very uniform, ranging from about 30 μm to 150 μm in emulsion 4 and from about 20 μm to 80 μm in emulsion 5.

[0289] The two emulsions prepared with GCC alone (emulsions 4 and 5) were unstable after 14 days with a separated oil phase. It was therefore not possible to measure the droplet size after the storage time.

[0290] The droplet sizes of Pickering emulsions / emulsions 6-17 were measured by light scattering after 21 days of storage at room temperature (if an emulsion had formed). Emulsions 6, 8, 9, 12, 13, 14, and 15 did not form an emulsion, but rather each phase (oil and water) existed separately in a mixture. The droplet size of emulsion 7 was 305 μm, emulsion 10 was 63 μm, emulsion 11 was 25 μm, emulsion 16 was 145 μm, and emulsion 17 was 54 μm.

[0291] The above experiments show that the volume median particle size d 50Stable Pickering emulsions are prepared using Pickering pigments having a value of 0.2 μm to 10 μm and thus containing no nanoparticles with a primary diameter substantially below 150 nm. Furthermore, as can be seen from the above experiments, these Pickering emulsions do not require, in addition to the Pickering pigment, additional emulsifiers or surfactants, stabilizers or surface coatings on the surface of the Pickering pigment to stabilize the droplets in the Pickering emulsion. Furthermore, the Pickering emulsions of the present invention are white. However, it is not possible to prepare such Pickering emulsions using only ground calcium carbonate (GCC) or only precipitated calcium carbonate (PCC). Using only the Pickering pigments of the present invention, stable Pickering emulsions can be prepared, which contain: water; 10-50 wt% of oil, based on the total weight of the Pickering emulsion, and 1-10 wt% of Pickering pigment, based on the total weight of the Pickering emulsion, and are stable within the claimed range.

Claims

1. Pickering emulsion comprising: (i) water; (ii) 10-50 wt% oil, based on the total weight of the Pickering emulsion, and (iii) 1 to 10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion, wherein the Pickering pigment is calcium carbonate particles selected from surface reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface reacted calcium carbonate (SRCC), and The calcium carbonate particles have a volume median particle size d of 0.2µm-10µm. 50 value, The surface-reacted calcium carbonate is natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + Ion donors are processed to be generated in situ and / or supplied from an external source, and The surface-reacted calcium carbonate has a volume median particle size d of 1.5µm-9.0µm. 50 Value, top cut particle size ≤20µm (d 98 (vol)), 10-200 m³ measured by the BET nitrogen method 2 The specific surface area (BET) of the sample is 0.1-2.3 cm / g and is calculated by mercury intrusion porosimetry. 3 / g of particles with internal pore volume.

2. The Pickering emulsion according to claim 1, wherein the ground calcium carbonate is selected from marble, limestone and / or chalk.

3. The Pickering emulsion according to claim 2, wherein the ground calcium carbonate is marble.

4. The Pickering emulsion according to any one of claims 1 to 3, wherein the ground calcium carbonate has: a) Volume median particle size d 0.3µm-5.0µm 50 value, and / or b) Top cut particle size ≤20µm (d 98 (vol)), and / or c) 0.5-50 m³ measured by the BET nitrogen method 2 / g specific surface area (BET).

5. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a volume median particle size d of 0.6 μm to 3 μm. 50 value.

6. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a volume median particle size d greater than 1.0 μm to 1.7 μm. 50 value.

7. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a top cut particle size (d 98 (vol)).

8. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a top cut particle size (d 98 (vol)).

9. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a top cut particle size (d 98 (vol)).

10. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a m / z of 0.5 to 35 m / z as measured by the BET nitrogen method. 2 / g specific surface area (BET).

11. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a m / z of 0.5 to 25 m / z as measured by the BET nitrogen method. 2 / g specific surface area (BET).

12. The Pickering emulsion according to claim 4, wherein the ground calcium carbonate has a m / z of 0.6 to 17 m / z as measured by the BET nitrogen method. 2 / g specific surface area (BET).

13. The Pickering emulsion according to any one of claims 1 to 3, wherein the surface-reacted calcium carbonate has: a) Volume median particle size d 2.5µm-7.5µm 50 value, and / or b) Top cut particle size ≤15µm (d 98 (vol)), and / or c) 20-180 m³ measured by the BET nitrogen method 2 / g specific surface area (BET), and / or d) 0.2-2.0 cm calculated by mercury intrusion method 3 / g of particles with internal pore volume.

14. The Pickering emulsion according to claim 13, wherein the surface-reacted calcium carbonate has a volume median particle size d of 3.3 μm to 6.6 μm. 50 value.

15. The Pickering emulsion according to claim 13, wherein the surface-reacted calcium carbonate has a top cut particle size (d 98 (vol)).

16. The Pickering emulsion according to claim 13, wherein the surface-reacted calcium carbonate has a top cut particle size (d 98 (vol)).

17. The Pickering emulsion according to claim 13, wherein the surface-reacted calcium carbonate has a carbon dioxide content of 25-140 m / s as measured by the BET nitrogen method. 2 / g specific surface area (BET).

18. The Pickering emulsion of claim 13, wherein the surface-reacted calcium carbonate has a carbon dioxide content of 48-110 m / s as measured by the BET nitrogen method. 2 / g specific surface area (BET).

19. The Pickering emulsion of claim 13, wherein the surface-reacted calcium carbonate has a surface area of 0.4-1.5 cm2 as calculated by mercury intrusion porosimetry. 3 / g of particles with internal pore volume.

20. The Pickering emulsion of claim 13, wherein the surface-reacted calcium carbonate has a surface area of 0.6-1.1 cm2 calculated by mercury intrusion porosimetry. 3 / g of particles with internal pore volume.

21. The Pickering emulsion of any one of claims 1-3, wherein the emulsion comprises 10-40 wt% oil, based on the total weight of the Pickering emulsion.

22. The Pickering emulsion according to claim 21, wherein the emulsion comprises 10-30 wt% oil, based on the total weight of the Pickering emulsion.

23. The Pickering emulsion of claim 21, wherein the emulsion comprises 10-20 wt% oil based on the total weight of the Pickering emulsion.

24. The Pickering emulsion of any one of claims 1 to 3, wherein the oil: selected from mineral oils, vegetable oils, animal fats, essential oils and mixtures thereof, and / or It is a refined oil with an acid value below 0.6, or an unrefined oil with an acid value below 4.

0.

25. The Pickering emulsion of claim 24, wherein the oil is selected from essential oils, sunflower oil, olive oil, palm oil, coconut oil, peanut oil, palm kernel oil, corn oil, hazelnut oil, sesame oil, and mixtures thereof.

26. The Pickering emulsion according to claim 24, wherein the oil is selected from sunflower oil, olive oil, palm oil and / or coconut oil.

27. The Pickering emulsion of claim 24, wherein the oil is sunflower oil.

28. The Pickering emulsion of claim 24, wherein the oil is a refined oil having an acid value of less than 0.

5.

29. The Pickering emulsion of claim 24, wherein the oil is a refined oil having an acid value of less than 0.

3.

30. The Pickering emulsion of claim 24, wherein the oil is an unrefined oil having an acid number below 3.

0.

31. The Pickering emulsion of claim 24, wherein the oil is an unrefined oil having an acid number below 2.

0.

32. The Pickering emulsion of any one of claims 1-3, wherein the emulsion comprises 2-10 wt% of a Pickering pigment, based on the total weight of the Pickering emulsion.

33. The Pickering emulsion according to claim 32, wherein the emulsion comprises 4-10 wt% of Pickering pigment based on the total weight of the Pickering emulsion.

34. The Pickering emulsion of claim 32, wherein the emulsion comprises 6-10 wt% of Pickering pigment based on the total weight of the Pickering emulsion.

35. The Pickering emulsion of any one of claims 1 to 3, wherein the emulsion comprises an additional active ingredient.

36. The Pickering emulsion of claim 35, wherein the additional active ingredient is selected from the group consisting of cosmetically active compounds, pharmaceutically active compounds, nutritional additives, flavoring agents, and mixtures thereof.

37. The Pickering emulsion of any one of claims 1-3, wherein the emulsion is stable against coalescence for at least 15 days.

38. The Pickering emulsion of claim 37, wherein the emulsion is stable against coalescence for at least 20 days.

39. The Pickering emulsion of claim 37, wherein the emulsion is stable against coalescence for at least 30 days.

40. The Pickering emulsion of any one of claims 1-3, wherein the emulsion contains no additional emulsifiers other than the Pickering pigment for stabilizing the droplets in the Pickering emulsion.

41. A composition comprising the Pickering emulsion according to any one of claims 1 to 40, wherein the composition is a food composition, a cosmetic composition, a pharmaceutical composition or a nutritional formula.

42. A method for preparing a Pickering emulsion, the method comprising the steps of: A) provide water, B) provide oil, C) providing a Pickering pigment, wherein the Pickering pigment is calcium carbonate particles selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and wherein the calcium carbonate particles have a volume median particle size d greater than 0.1 μm to 10 μm 50 value, D) combining the water of step A), the oil of step B), and the Pickering pigment of step C) in any order to obtain a mixture comprising 10-50 wt% of the oil based on the total weight of the mixture and 1-10 wt% of the Pickering pigment based on the total weight of the mixture, and E) mixing the mixture obtained in step D) to prepare a Pickering emulsion, The surface-reacted calcium carbonate is natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + Ion donors are processed to be generated in situ and / or supplied from an external source, and The surface-reacted calcium carbonate has a volume median particle size d of 1.5µm-9.0µm. 50 Value, top cut particle size ≤20µm (d 98 (vol)), 10-200 m³ measured by the BET nitrogen method 2 The specific surface area (BET) of the sample is 0.1-2.3 cm / g and is calculated by mercury intrusion porosimetry. 3 / g of particles with internal pore volume.

43. The method according to claim 42, wherein the surface of the Pickering pigment provided in step C) is not coated with a surface treatment agent.

44. The method according to claim 42, wherein the surfaces of the Pickering pigment and the surface-reacted calcium carbonate particles provided in step C) are not coated with a surface treatment agent.

45. Use of calcium carbonate particles as Pickering pigments for stabilizing a Pickering emulsion comprising water and 10-50 wt% of oil, based on the total weight of the Pickering emulsion, wherein the calcium carbonate particles are selected from surface-reacted calcium carbonate (SRCC) or a mixture of ground calcium carbonate (GCC) and surface-reacted calcium carbonate (SRCC), and have a volume median particle size d of 0.2 μm to 10 μm. 50 value, The surface-reacted calcium carbonate is natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O + The reaction product of the ion donor, wherein the carbon dioxide is passed through H3O + Ion donors are processed to be generated in situ and / or supplied from an external source, and The surface-reacted calcium carbonate has a volume median particle size d of 1.5µm-9.0µm. 50 Value, top cut particle size ≤20µm (d 98 (vol)), 10-200 m³ measured by the BET nitrogen method 2 The specific surface area (BET) of the sample is 0.1-2.3 cm / g and is calculated by mercury intrusion porosimetry. 3 / g of particles with internal pore volume.

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