The present invention relates to a surface-modified material, a method for its production and its use.

Controlling, modifying and tailoring the surface properties of materials remains of high interest in various technological fields and industries. Slippery liquid infused porous surfaces (SLIPS) is a technology for functionalizing material surfaces, which has been firstly described in 201 1 (Wong et al., Nature 2011 , 477, 433), and has gained much attention. Said technology is actively studied and already used for many applications. SLIPS combines a lubricated film on a porous solid material to create surfaces that exhibit ultra-liquid repellency, self-healing, optical transparency, pressure stability, and self-cleaning (cf. Wyss Institute at Harvard University, SLIPS). The reported porous surfaces are mainly made of materials having a low surface energy such as PTFE and/ or materials that have a silane or similar coating to reduce the surface energy of the base material. Typically, low surface tension liquids such as fluorocarbones, hydrophobic oils, or silicon oils are infused into those structures (see e.g. WO2012100099). These materials, however, are fossil-based, aggressive to the environment, and often highly toxic, which is especially problematic because a common problem with SLIPS is their lack of robustness and durability. Moreover, the production of such materials is complex and expensive, making upscaling challenging.

WO2018022736 A1 describes a composition for creating a functionalized, roughened surface in a single application, the composition comprising nanoparticles having a narrow particle size distribution, a binder, and an additive, wherein the composition provides a uniformly-textured surface suitable for forming a smooth liquid lubricant overlayer surface. WO2017068378 A1 discloses an article that is at least partially covered with a coating defining a slippery surface, the coating comprising a layer of a composite particulate material bound to said article and a substantially immobilised lubricant at least partially covering and penetrating into said layer of composite particulate material, wherein the composite particulate material comprises carrier particles at least partially coated with a hydrophobic material. SLIPS fabricated on paper substrates are studied in the article of Mikriukova et al. published in Nordic Pulp & Paper Research Journal 2020, 35(3), 479.

Thus, there remains a need in the art for further methods for functionalizing material surfaces and tuning surface properties of materials.

Accordingly, it is an object of the present invention to provide a method for modifying the surface properties of a substrate in a controlled manner. It would be desirable to provide a method for creating hydrophobic as well as hydrophilic surfaces, which can be equipped with additional functionalities such as antimicrobial, antifungal, antivirus, stain repellant, paint repellant, self repairing, slippery or insect and other parasites eliminating properties, if needed. It is also desirable that the method is easy to implement in existing production facilities and is suitable for both small and large production volume. Furthermore, it is desirable that the method can be used for a great variety of substrates.

It is also an object of the present invention to provide a surface-modified material which can be utilized in a great variety of applications. It would be desirable to provide a surface-modified material, which is at least partially derivable from natural sources and can be produced from materials that are environmentally benign and inexpensive.

The foregoing and other objects are solved by the subject-matter as defined herein in the independent claims.

According to one aspect of the present invention, a method of manufacturing a surface- modified material is provided, wherein the method comprises the steps of: a) providing a substrate comprising at least one surface, b) providing a coating composition comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, c) providing an infusing liquid composition, d) applying the coating composition of step b) onto at least one surface of the substrate of step a) and drying the applied coating composition to form a porous coating layer on the at least one surface of the substrate, and e) infusing the porous coating layer obtained in step d) with at least 150 wt.-%, based on the total weight of the porous coating layer, of the infusing liquid composition of step c) to form a contained liquid layer within and on the porous coating layer, wherein the infused liquid composition is chemically inert to the substrate and the porous coating layer obtained in step d).

According to a further aspect of the present invention, a surface-modified material is provided, comprising a substrate comprising at least one surface, a porous coating layer comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, wherein the porous coating layer is in contact with the at least one surface of the substrate, and a contained liquid layer within and on the porous coating layer, wherein the contained liquid layer is chemically inert to the substrate and the porous coating layer, and the contained liquid layer is present in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to still a further aspect of the present invention, an article comprising the surface- modified material according to the present invention is provided, preferably the article is selected from paper products, engineered wood products, plasterboard products, polymer products, hygiene products, medical products, healthcare products, filter products, woven materials, nonwoven materials, geotextile products, agriculture products, horticulture products, clothing, footwear products, baggage products, household products, industrial products, packaging products, building products, construction products, fluid transport products, or anti-icing products.

According to still a further aspect of the present invention, use of a surface-modified material according to the present invention is provided in microfluidic systems, in building applications, construction applications, fluid transport applications, anti-icing applications, anti-bacterial applications, anti-viral applications, anti-mold applications, pest control materials, self cleaning surfaces, self-repairing surfaces, textile production, or shoe production. According to still a further aspect of the present invention, use of a substrate comprising a porous coating layer for containing an infusing liquid composition which is chemically inert to the substrate and the porous coating layer is provided, wherein the porous coating layer is in contact with at least one surface of the substrate, the porous coating layer comprises mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, and the porous coating layer is capable of containing the infused liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to still a further aspect of the present invention, a kit of parts for preparing a surface-modified material is provided, the kit of parts comprising a substrate comprising at least one surface, a coating composition for forming a porous coating layer on the at least one surface of the substrate, wherein the coating composition comprises mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, and an infusing liquid composition, optionally a liquid hydrophobising composition, wherein the porous coating layer is capable of the infusing liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer, and wherein the infusing liquid composition is chemically inert to the substrate and the porous coating layer.

Advantageous embodiments of the present invention are defined in the corresponding subclaims.

According to one embodiment the substrate is selected from the group comprising paper, cardboard, containerboard, plastic, non-wovens, cellophane, textile, wood, metal, glass, mica plate, marble, calcite, nitrocellulose, natural stone, composite stone, brick, concrete, and laminates or composites thereof, preferably the substrate is selected from the group comprising paper, cardboard, containerboard, plastic, and laminates or composites thereof. According to a further embodiment the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, and/or the coating composition comprises the binder in an amount from 1 to 50 wt.-%, based on the total weight of the mineral particles, preferably from 3 to 30 wt.-%, and most preferably from 5 to 15 wt.-%.

According to one embodiment the mineral particles have a volume determined median particle size dso from 1 to 75 pm, preferably from 0.3 to 50 pm, more preferably from 0.5 to 40 pm, even more preferably from 0.8 to 30 pm, and most preferably from 1 to 15 pm, and/or a volume determined top cut particle size dgs from 0.2 to 150 pm, preferably from 0.6 to 100 pm, more preferably from 1 to 80 pm, even more preferably from 1 .6 to 60 pm, and most preferably from 2 to 30 pm, and/or a specific surface area in the range from 1 to 200 m ² /g, preferably from 2 to 150 m ² /g, and most preferably from 5 to 110 m ² /g, measured using nitrogen and the BET method according to ISO 9277:2010.

According to one embodiment the calcium carbonate is ground calcium carbonate, precipitated calcium carbonate, or surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors, and/or the hydromagnesite is precipitated hydromagnesite. According to a further embodiment the mineral particles are surface-treated with a surface treatment agent or are a blend of surface-treated mineral particles and non-surface treated mineral particles, preferably the surface treatment agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

According to one embodiment the infusing liquid composition is a hydrophobic infusing liquid composition, preferably selected from the group consisting of a fluorinated hydrocarbon, an organosilicone compound, a long-chain hydrocarbon, or a mixture thereof, or a hydrophilic infusing liquid composition, preferably selected from the group consisting of an aqueous solution, a diol, a triol, a hydrophilic hydrocarbon, a hydrophilic silicone, and a mixture thereof. According to a further embodiment the infusing liquid composition has a viscosity from 1 to 1450 mPa s at 20°C, preferably from 2 to 1000 mPa s at 20°C, more preferably from 5 to 500 mPa s at 20°C, even more preferably from 8 to 300 mPa s at 20°C, and most preferably from 10 to 100 mPa s at 20°C and/or the infusing liquid composition has a standard boiling point of at least 100°C, preferably of at least 150°C, more preferably at least 200°C, and most preferably at least 290°C, and/or the infusing liquid composition has a vapour pressure of less than 1000 Pa at 20°C, preferably less than 900 Pa at 20°C, more preferably less than 800 Pa at 20°C, and most preferably less than 700 Pa at 20°C, and/or the infusing liquid composition has a surface tension from 1 to 72 mN/m at 20°C, preferably from 5 to 60 mN/m at 20°C, more preferably from 10 to 50 mN/m at 20°C, and most preferably from 15 to 40 mN/m at 20°C.

According to one embodiment the mineral particles are calcium carbonate, preferably surface- reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors, wherein the calcium carbonate is surface-treated with a surface treatment agent, preferably selected from saturated or unsaturated fatty acids, the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, preferably the binder is selected from the group consisting of styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, and most preferably the binder is a styrene-acrylate latex, and the infusing liquid composition is a silicon oil. According to a further embodiment the mineral particles are surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors, the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, preferably the binder is selected from the group consisting of styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, and most preferably the binder is a styrene-acrylate latex, and the infusing liquid composition is a solution comprising water, alcohol, and an active agent, preferably a biocide or pesticide, and more preferably an insecticide.

According to one embodiment step e) is carried out until the porous coating layer is saturated, preferably step e) is carried out for at least 1 min or at least 5 min, preferably at least 15 min, more preferably at least 30 min, even more preferably at least 1 h, still more preferably at least 2 h, and most preferably at least 4 h. According to a further embodiment the porous coating layer obtained in step d) is infused with at least 200 wt.-%, preferably at least 250 wt.-%, more preferably at least 300 wt.-%, and most preferably at least 350 wt.-%, based on the total weight of the porous coating layer, of the infusing liquid composition of step c) to form a contained liquid layer within and on the porous coating layer.

According to one embodiment the method further comprises the steps of f) providing a liquid hydrophobising composition, and g) applying the liquid hydrophobising composition onto at least one surface of the porous coating layer obtained in step d), and drying the applied liquid hydrophobising composition to form a hydrophobic porous coating layer, wherein steps f) and g) are carried out after step d) and before step e).

According to one embodiment the porous coating layer has a maximum roughness PSq from 1 to 4 pm, preferably from 1 .1 to 3.5 pm, more preferably from 1 .2 to 3 pm, and most preferably from 1 .2 to 2.9 pm, measured by confocal microscopy, and/or a waviness WSq from 0.2 to 6 pm, preferably from 0.3 to 5.8 pm, more preferably from 0.4 to 5.5 pm, and most preferably from 0.4 to 5.2, measured by confocal microscopy, and/or a total intruded pore volume in the range from 0.2 to 1 .1 cm ³ /g, preferably from 0.25 to 1 cm ³ /g, more preferably from 0.3 to 0.95 cm ³ /g, and most preferably from 0.31 to 0.9 cm ³ /g, measured by mercury intrusion porosimetry. According to a further embodiment the surface gloss G20 of the surface-modified material is increased by at least 0.5%, preferably by at least 0.6%, more preferably by at least 1 %, even more preferably by at least 1 .4%, and most preferably by at least 2%, compared to the surface gloss G20 of the same surface-modified material without the contained liquid layer within and above the porous coating layer, wherein surface gloss G20 is measured with a polarized light reflectometer at a nominal 20° acceptance angle.

It should be understood that for the purpose of the present invention, the following terms have the following meaning.

For the purpose of the present invention, an “acid” is defined as Bnansted-Lowry acid, that is to say, it is an HsO ⁺ ion provider. The term “free acid” refers only to those acids being in the fully protonated form (e.g., H2SO4). An “acidic salt” is defined as an HsO ⁺ ion-provider, e.g., a hydrogencontaining salt, which is partially neutralised by an electropositive element. A “salt” is defined as an electrically neutral ionic compound formed from anions and cations. A “partially crystalline salt” is defined as a salt that, on XRD analysis, presents an essentially discrete diffraction pattern. In accordance with the present invention, pK _a , is the symbol representing the acid dissociation constant associated with a given ionisable hydrogen in a given acid, and is indicative of the natural degree of dissociation of this hydrogen from this acid at equilibrium in water at a given temperature. Such pK _a values may be found in reference textbooks such as Harris, D. C. “Quantitative Chemical Analysis: 3 ^rd Edition”, 1991 , W.H. Freeman & Co. (USA), ISBN 0-7167-2170-8.

The term “basis weight” as used in the present invention is determined according to DIN EN ISO 536:1996, and is defined as the weight in g/m ² .

For the purpose of the present invention, the term “coating layer” refers to a layer, covering, film, skin etc., formed, created, prepared etc., from a coating composition which remains predominantly on one surface of the substrate. The coating layer can be in direct contact with the surface of the substrate or, in case the substrate comprises one or more precoating layers and/or barrier layers, can be in direct contact with the top precoating layer or barrier layer, respectively.

The term “infusing liquid composition” as used herein, refers to a composition in liquid form, which can be applied the porous coating layer of the substrate of the present invention and is chemically inert to the substrate and porous coating layer.

For the purpose of the present invention, the expression “chemically inert” shall be used to indicate that a material or substance is not chemically reactive, i.e. the material or substance does not undergo a chemical reaction either by itself or with another material.

The term “contained liquid layer” in the meaning of the present invention refers to a liquid composition which is immobilized or locked in place by the porous coating layer resulting in a layer of a liquid film within and on the porous coating layer, which is basically incompressible and can repel immiscible fluids.

“Natural ground calcium carbonate” (GCC) in the meaning of the present invention is a calcium carbonate obtained from natural sources, such as limestone, marble, or chalk, and processed through a wet and/or dry treatment such as grinding, screening and/or fractionating, for example, by a cyclone or classifier.

“Precipitated calcium carbonate” (PCC) in the meaning of the present invention is a synthesised material, obtained by precipitation following reaction of carbon dioxide and lime in an aqueous, semi-dry or humid environment or by precipitation of a calcium and carbonate ion source in water. PCC may be in the vateritic, calcitic or aragonitic crystal form. PCCs are described, for example, in EP2447213 A1 , EP2524898 A1 , EP2371766 A1 , EP1712597 A1 , EP1712523 A1 , or WO2013142473 A1.

The term “surface-reacted” in the meaning of the present application shall be used to indicate that a material has been subjected to a process comprising partial dissolution of said material upon treatment with an H ₃ O ⁺ ion donor (e.g., by use of water-soluble free acids and/or acidic salts) in aqueous environment followed by a crystallization process which may occur in the absence or presence of further crystallization additives.

An “H ₃ O ⁺ ion donor” in the context of the present invention is a Bnansted acid and/or an acid salt, i.e. a salt containing an acidic hydrogen.

The “particle size” of particulate materials, other than mineral particles, herein is described by its weight-based distribution of particle sizes d _x . Therein, the value d _x represents the diameter relative to which x % by weight of the particles have diameters less than d _x . This means that, for example, the d2o value is the particle size at which 20 wt.-% of all particles are smaller than that particle size. The dso value is thus the weight median particle size, i.e. 50 wt.-% of all particles are smaller than this particle size. For the purpose of the present invention, the particle size is specified as weight median particle size dso(wt) unless indicated otherwise. Particle sizes were determined by using a Sedigraph™ 5100 instrument or Sedigraph™ 5120 instrument of Micromeritics Instrument Corporation. The method and the instrument are known to the skilled person and are commonly used to determine the particle size of fillers and pigments. The measurements were carried out in an aqueous solution of 0.1 wt.-% N84P2O7.

The “particle size” of the mineral particles herein is described as volume-based particle size distribution. Volume-based median particle size dso was evaluated using a Malvern Mastersizer 2000 or 3000 Laser Diffraction System. The dso or dos value, measured using a Malvern Mastersizer 2000 or 3000 Laser Diffraction System, indicates a diameter value such that 50 % or 98 % by volume, respectively, of the particles have a diameter of less than this value. The raw data obtained by the measurement are analysed using the Mie theory, with a particle refractive index of 1 .57 and an absorption index of 0.005.

The term “particulate” in the meaning of the present application refers to materials composed of a plurality of particles. Said plurality of particles may be defined, for example, by its particle size distribution. The expression “particulate material” may comprise granules, powders, grains, tablets, or crumbles.

The “specific surface area” (expressed in m ² /g) of a material as used throughout the present document can be determined by the Brunauer Emmett Teller (BET) method with nitrogen as adsorbing gas and by use of a ASAP 2460 instrument from Micromeritics. The method is well known to the skilled person and defined in ISO 9277:2010. Prior to such measurements, the sample was filtered within a Buchner funnel, rinsed with deionised water and dried at 110°C in an oven for at least 12 hours. The total surface area (in m ² ) of said material can be obtained by multiplication of the specific surface area (in m ² /g) and the mass (in g) of the material.

In the context of the present invention, the term “pore” is to be understood as describing the space that is found between and/or within particles, i.e. that is formed by the particles as they pack together under nearest neighbour contact (interparticle pores), such as in a powder or a compact and/or the void space within porous particles (intra particle pores), and that allows the passage of liquids under pressure when saturated by the liquid and/or supports absorption of surface wetting liquids.

Unless specified otherwise, the term “drying” refers to a process according to which at least a portion of water is removed from a material to be dried such that a constant weight of the obtained “dried” material at 200°C is reached. Moreover, a “dried” or “dry” material may be defined by its total moisture content which, unless specified otherwise, is less than or equal to 1 .0 wt.-%, preferably less than or equal to 0.5 wt.-%, more preferably less than or equal to 0.2 wt.-%, and most preferably between 0.03 and 0.07 wt.-%, based on the total weight of the dried material.

For the purpose of the present application, “water-insoluble” materials are defined as those which, when mixed with 100 ml of deionised water and filtered at 20°C to recover the liquid filtrate, provide less than or equal to 0.1 g of recovered solid material following evaporation at 95 to 100°C of 100 g of said liquid filtrate. “Water-soluble” materials are defined as materials leading to the recovery of greater than 0.1 g of solid material following evaporation at 95 to 100°C of 100 g of said liquid filtrate. In order to assess whether a material is an insoluble or soluble material in the meaning of the present invention, the sample size is greater than 0.1 g, preferably 0.5 g or more.

For the purpose of the present invention, the “solids content” of a liquid composition is a measure of the amount of material remaining after all the solvent or water has been evaporated. If necessary, the “solids content” of a suspension given in wt.-% in the meaning of the present invention can be determined using a Moisture Analyzer HR73 from Mettler-Toledo (T = 120 °C, automatic switch off 3, standard drying) with a sample size of 5 to 20 g.

A “suspension” or “slurry” in the meaning of the present invention comprises undissolved solids and water, and optionally further additives, and usually contains large amounts of solids and, thus, is more viscous and can be of higher density than the liquid from which it is formed.

The term “aqueous” suspension refers to a system, wherein the liquid phase comprises, preferably consists of, water. However, said term does not exclude that the liquid phase of the aqueous suspension comprises minor amounts of at least one water-miscible organic solvent selected from the group comprising methanol, ethanol, acetone, acetonitrile, tetrahydrofuran and mixtures thereof. If the aqueous suspension comprises at least one water-miscible organic solvent, the liquid phase of the aqueous suspension may comprise the at least one water-miscible organic solvent in an amount of from 0.1 to 40.0 wt.-% preferably from 0.1 to 30.0 wt.-%, more preferably from 0.1 to 20.0 wt.-% and most preferably from 0.1 to 10.0 wt.-%, based on the total weight of the liquid phase of the aqueous suspension. For example, the liquid phase of the aqueous suspension may consist of water.

Where an indefinite or definite article is used when referring to a singular noun, e.g., “a”, “an” or “the”, this includes a plural of that noun unless anything else is specifically stated.

Where the term “comprising” is used in the present description and claims, it does not exclude other elements. For the purposes of the present invention, the term “consisting of’ is considered to be a preferred embodiment of the term “comprising”. If hereinafter a group is defined to comprise at least a certain number of embodiments, this is also to be understood to disclose a group, which preferably consists only of these embodiments.

Terms like “obtainable” or “definable” and “obtained” or “defined” are used interchangeably. This, for example, means that, unless the context clearly dictates otherwise, the term “obtained” does not mean to indicate that, for example, an embodiment must be obtained by, for example, the sequence of steps following the term “obtained” though such a limited understanding is always included by the terms “obtained” or “defined” as a preferred embodiment.

Whenever the terms “including” or “having” are used, these terms are meant to be equivalent to “comprising” as defined hereinabove.

According to the present invention, a method of manufacturing a surface-modified material is provided, wherein the method comprises the steps of: a) providing a substrate comprising at least one surface, b) providing a coating composition, c) providing an infusing liquid composition, d) applying the coating composition of step b) onto at least one surface of the substrate of step a) and drying the applied coating composition to form a porous coating layer on the at least one surface of the substrate, and e) infusing the porous coating layer obtained in step d) with at least 150 wt.-%, based on the total weight of the porous coating layer, of the infusing liquid composition of step c) to form a contained liquid layer within and on the porous coating layer. The coating composition comprises mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, and the liquid treatment composition is chemically inert to the substrate and the porous coating layer obtained in step d).

In the following details and preferred embodiments of the inventive method will be set out in more details. It is to be understood that these technical details and embodiments also apply to the inventive surface-modified material, an article comprising the same, its use, and a corresponding kit.

Method step a)

According to step a) of the method of the present invention, a substrate is provided, which comprises at least one surface.

The substrate serves as a support for the porous coating layer and may be opaque, translucent, or transparent.

According to one embodiment, the substrate is selected from the group comprising paper, cardboard, containerboard, plastic, non-wovens, cellophane, textile, wood, metal, glass, mica plate, marble, calcite, nitrocellulose, natural stone, composite stone, brick, concrete, and laminates or composites thereof. According to a preferred embodiment, the substrate is selected from the group comprising paper, cardboard, containerboard, plastic, and laminates or composites thereof. According to another embodiment, the substrate is a laminate of paper, plastic and/or metal, wherein preferably the plastic and/or metal are in form of thin foils such as for example used in Tetra Pak. However, any other material having a surface suitable for printing, coating or painting on may also be used as substrate.

According to one embodiment of the present invention, the substrate is paper, cardboard, or containerboard. Cardboard may comprise carton board or boxboard, corrugated cardboard, or nonpackaging cardboard such as chromoboard, or drawing cardboard. Containerboard may encompass linerboard and/or a corrugating medium. Both linerboard and a corrugating medium are used to produce corrugated board. The paper, cardboard, or containerboard substrate can have a basis weight from 10 to 1000 g/m ² , from 20 to 800 g/m ² , from 30 to 700 g/m ² , or from 50 to 600 g/m ² . According to one embodiment, the substrate is paper, preferably having a basis weight from 10 to 400 g/m ² , 20 to 300 g/m ² , 30 to 200 g/m ² , 40 to 100 g/m ² , 50 to 90 g/m ² , 60 to 80 g/m ² , or about 70 g/m ² .

According to another embodiment, the substrate is a plastic substrate. Suitable plastic materials are, for example, polyethylene, polypropylene, polyvinylchloride, polyesters, polycarbonate resins, or fluorine-containing resins, preferably polypropylene. Examples for suitable polyesters are polyethylene terephthalate), polyethylene naphthalate) or polyester diacetate). An example for a fluorine-containing resins is poly(tetrafluoro ethylene). The plastic substrate may be filled by a mineral filler, an organic pigment, an inorganic pigment, or mixtures thereof.

The substrate may consist of only one layer of the above-mentioned materials or may comprise a layer structure having several sublayers of the same material or different materials. According to one embodiment, the substrate is structured by one layer. According to another embodiment the substrate is structured by at least two sublayers, preferably three, five, or seven sublayers, wherein the sublayers can have a flat or non-flat structure, e.g. a corrugated structure. Preferably the sublayers of the substrate are made from paper, cardboard, containerboard and/or plastic.

The substrate may be permeable or impermeable for solvents, water, or mixtures thereof. According to one embodiment, the substrate is impermeable for water, solvents, or mixtures thereof. Examples for solvents aliphatic alcohols, ethers and diethers having from 4 to 14 carbon atoms, glycols, alkoxylated glycols, glycol ethers, alkoxylated aromatic alcohols, aromatic alcohols, mixtures thereof, or mixtures thereof with water.

According to one embodiment, the substrate is impermeable for the infusing liquid composition.

According to another embodiment, the substrate has a porous structure, wherein the pores have been filled with a liquid, e.g., glycol, glycerol, and/or water.

The substrate provided in step a) may comprise one or more precoating layers and/or barrier layers.

According to one embodiment, the substrate comprises one or more precoating layers. Such precoating layers may comprise kaolin, silica, talc, plastic, precipitated calcium carbonate, modified calcium carbonate, ground calcium carbonate, or mixtures thereof. In this case, the porous coating layer applied in method step d) described further below, may be in direct contact with the surface of the precoating layer, or, if more than one precoating layer is present, the porous coating layer may be in direct contact with the surface of the top precoating layer.

According to another embodiment of the present invention, the substrate comprises one or more barrier layers. In this case, the porous coating layer applied in method step d) described further below, may be in direct contact with the surface of the barrier layer, or, if more than one barrier layer is present, the coating layer may be in direct contact with the surface of the top barrier layer. The barrier layer may comprise a polymer, for example, polyvinyl alcohol, polyvinyl pyrrolidone, gelatin, cellulose ethers, polyoxazolines, polyvinylacetamides, partially hydrolyzed polyvinyl acetate/vinyl alcohol, polyacrylic acid, polyacrylamide, polyalkylene oxide, sulfonated or phosphated polyesters and polystyrenes, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodian, agar-agar, arrowroot, guar, carrageenan, starch, tragacanth, xanthan, rhamsan, poly(styrene-co- butadiene), polyurethane latex, polyester latex, poly(n-butyl acrylate), poly(n-butyl methacrylate), poly(2-ethylhexyl acrylate), copolymers of n-butylacrylate and ethylacrylate, copolymers of vinylacetate and n-butylacrylate, and the like and mixtures thereof. Further examples of suitable barrier layers are homopolymers or copolymers of acrylic and/or methacrylic acids, itaconic acid, and acid esters, such as e.g. ethylacrylate, butyl acrylate, styrene, unsubstituted or substituted vinyl chloride, vinyl acetate, ethylene, butadiene, acrylamides and acrylonitriles, silicone resins, water dilutable alkyd resins, acrylic/alkyd resin combinations, natural oils such as linseed oil, and mixtures thereof. According to one embodiment, the barrier layer comprises latexes, polyolefins, polyvinylalcohols, kaolin, talcum, mica for creating tortuous structures (stacked structures), and mixtures thereof.

According to one embodiment, the substrate comprises one or more barrier layer(s), which is/are impermeable for the infusing liquid composition. According to still another embodiment of the present invention, the substrate comprises one or more precoating and barrier layers. In this case, the porous coating layer applied in method step d) described further below, may be in direct contact with the surface of the top precoating layer or barrier layer, respectively.

According to one embodiment, the substrate comprises plastic, preferably polypropylene.

Method step b)

According to step b) of the method of the present invention, a coating composition is provided comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder.

According to one embodiment the mineral filler is in form of particles having a volume determined median particle size cko from 0.1 to 75 pm, preferably from 0.3 to 50 pm, more preferably from 0.5 to 40 pm, even more preferably from 0.8 to 30 pm, and most preferably from 1 to 15 pm. The volume determined median particle size cfeo was evaluated using a Malvern Mastersizer 2000 Laser Diffraction System.

Additionally or alternatively, the mineral filler is in form of particles having a volume determined top cut particle size dgs from 0.2 to 150 pm, preferably from 0.6 to 100 pm, more preferably from 1 to 80 pm, even more preferably from 1 .6 to 60 pm, and most preferably from 2 to 30 pm. The volume determined top cut particle size dgs was evaluated using a Malvern Mastersizer 2000 Laser Diffraction System.

Additionally or alternatively, the mineral filler is in form of particles having a specific surface area in the range from 1 to 200 m ² /g, preferably from 2 to 150 m ² /g, and most preferably from 5 to 110 m ² /g, measured using nitrogen and the BET method according to ISO 9277:2010.

According to one embodiment of the present invention, the coating composition is an aqueous composition, i.e. a composition comprising water as solvent, and preferably containing water as the only solvent. According to another embodiment, the coating composition is a non-aqueous composition. Suitable solvents are known to the skilled person and are, for example, aliphatic alcohols, ethers and diethers having from 4 to 14 carbon atoms, glycols, alkoxylated glycols, glycol ethers, alkoxylated aromatic alcohols, aromatic alcohols, mixtures thereof, or mixtures thereof with water.

According to one embodiment of the present invention, the solids content of the coating composition is in the range from 5 wt.-% to 75 wt.-%, preferably from 10 to 60 wt.-%, more preferably from 15 to 50 wt.-%, and most preferably from 20 to 40 wt.-%, based on the total weight of the composition. According to a preferred embodiment, the coating composition is an aqueous composition having a solids content in the range from 5 wt.-% to 75 wt.-%, preferably from 10 to 60 wt.-%, more preferably from 15 to 60 wt.-%, and most preferably from 20 to 40 wt.-%, based on the total weight of the composition.

According to one embodiment of the present invention, the coating composition has a Brookfield viscosity of between 1 and 4000 mPa s at 20°C, preferably between 5 and 3000 mPa s at 20°C, more preferably between 10 and 2000 mPa s at 20°C, and most preferably between 20 and 900 mPa s at 20°C. The skilled person will adapt the composition of the coating composition and its physical properties to the characteristics of the substrate. For example, the coating composition may be a paper coating composition, a plastic coating composition, a paint, a metal coating composition, a concrete coating composition, and/or a wood coating composition.

Calcium carbonate

According to one embodiment, the mineral particles are calcium carbonate or a mixture of calcium carbonate and hydromagnesite and/or calcium phosphate. The calcium carbonate may be ground calcium carbonate, precipitated calcium carbonate, surface-reacted calcium carbonate, or a mixture thereof, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors. According to a preferred embodiment, the mineral filler is selected from precipitated calcium carbonate.

Ground calcium carbonate

Ground (or natural ground) calcium carbonate (GCC) is understood to be manufactured from a naturally occurring form of calcium carbonate, mined from sedimentary rocks such as limestone or chalk, or from metamorphic marble rocks, eggshells or seashells. Calcium carbonate is known to exist as three types of crystal polymorphs: calcite, aragonite and vaterite. Calcite, the most common crystal polymorph, is considered to be the most stable crystal form of calcium carbonate. Less common is aragonite, which has a discrete or clustered needle orthorhombic crystal structure. Vaterite is the rarest calcium carbonate polymorph and is generally unstable. Ground calcium carbonate is almost exclusively of the calcitic polymorph, which is said to be trigonal-rhombohedral and represents the most stable of the calcium carbonate polymorphs. The term “source” of the calcium carbonate in the meaning of the present application refers to the naturally occurring mineral material from which the calcium carbonate is obtained. According to one embodiment of the present invention, the ground calcium carbonate is selected from the group consisting of marble, chalk, limestone and mixtures thereof. The source of the calcium carbonate may comprise further naturally occurring components such as magnesium carbonate, alumino silicate etc.

According to one embodiment of the present invention the GCC is obtained by dry grinding. According to another embodiment of the present invention the GCC is obtained by wet grinding and optionally subsequent drying.

In general, the grinding step can be carried out with any conventional grinding device, for example, under conditions such that comminution predominantly results from impacts with a secondary body, i.e. in one or more of: a ball mill, a rod mill, a vibrating mill, a roll crusher, a centrifugal impact mill, a vertical bead mill, an attrition mill, a pin mill, a hammer mill, a pulveriser, a shredder, a de-clumper, a knife cutter, or other such equipment known to the skilled man. In case the calcium carbonate comprising mineral material comprises a wet ground calcium carbonate comprising mineral material, the grinding step may be performed under conditions such that autogenous grinding takes place and/or by horizontal ball milling, and/or other such processes known to the skilled man. The wet processed ground calcium carbonate comprising mineral material thus obtained may be washed and dewatered by well-known processes, e.g. by flocculation, centrifugation, filtration or forced evaporation prior to drying. The subsequent step of drying may be carried out in a single step such as spray drying, or in at least two steps. It is also common that such a mineral material undergoes a beneficiation step (such as a flotation, bleaching or magnetic separation step) to remove impurities.

According to one embodiment of the present invention, the calcium carbonate comprises one type of ground calcium carbonate. According to another embodiment of the present invention, the calcium carbonate comprises a mixture of two or more types of ground calcium carbonates selected from different sources.

Precipitated calcium carbonate

“Precipitated calcium carbonate” (PCC) in the meaning of the present invention is a synthesized material, generally obtained by precipitation following reaction of carbon dioxide and calcium hydroxide in an aqueous environment or by precipitation of calcium and carbonate ions, for example CaCh and Na2CO ₃ , out of solution. Further possible ways of producing PCC are the lime soda process, or the Solvay process in which PCC is a by-product of ammonia production. Precipitated calcium carbonate exists in three primary crystalline forms: calcite, aragonite and vaterite, and there are many different polymorphs (crystal habits) for each of these crystalline forms. Calcite has a trigonal structure with typical crystal habits such as scalenohedral (S-PCC), rhombohedral (R- PCC), hexagonal prismatic, pinacoidal, colloidal (C-PCC), cubic, and prismatic (P-PCC). Aragonite is an orthorhombic structure with typical crystal habits of twinned hexagonal prismatic crystals, as well as a diverse assortment of thin elongated prismatic, curved bladed, steep pyramidal, chisel shaped crystals, branching tree, and coral or worm-like form. Vaterite belongs to the hexagonal crystal system. The obtained PCC slurry can be mechanically dewatered and dried.

According to one embodiment of the present invention, the precipitated calcium carbonate is precipitated calcium carbonate, preferably comprising aragonitic, vateritic or calcitic mineralogical crystal forms or mixtures thereof.

According to one embodiment of the present invention, the calcium carbonate comprises one precipitated calcium carbonate. According to another embodiment of the present invention, the calcium carbonate comprises a mixture of two or more precipitated calcium carbonates selected from different crystalline forms and different polymorphs of precipitated calcium carbonate. For example, the at least one precipitated calcium carbonate may comprise one PCC selected from S-PCC and one PCC selected from R-PCC.

Surface-reacted calcium carbonate

The surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more H ₃ O ⁺ ion donors.

A H ₃ O ⁺ ion donor in the context of the present invention is a Bnansted acid and/or an acid salt. Precipitated calcium carbonate may be ground prior to the treatment with at least one H ₃ O ⁺ ion donor by the same means as used for grinding natural calcium carbonate as described above.

According to one embodiment of the present invention, the natural ground or precipitated calcium carbonate, which is used for the production of surface-reacted calcium carbonate, is in form of particles having a weight median particle size cfeo of 0.05 to 10.0 pm, preferably 0.2 to 5.0 pm, more preferably 0.4 to 3.0 pm, most preferably 0.6 to 1 .2 pm, especially 0.7 pm. According to a further embodiment of the present invention, the natural or precipitated calcium carbonate is in form of particles having a top cut particle size ck _s of 0.15 to 55 pm, preferably 1 to 40 pm, more preferably 2 to 25 pm, most preferably 3 to 15 pm, especially 4 pm.

The natural ground and/or precipitated calcium carbonate may be used dry or suspended in water. Preferably, a corresponding slurry has a content of natural or precipitated calcium carbonate within the range of 1 wt.-% to 90 wt.-%, more preferably 3 wt.-% to 60 wt.-%, even more preferably 5 wt.-% to 40 wt.-%, and most preferably 10 wt.-% to 25 wt.-% based on the weight of the slurry.

The one or more HsO ⁺ ion donor used for the preparation of surface reacted calcium carbonate may be any acidgenerating HsO ⁺ ions under the preparation conditions. According to the present invention, the at least one HsO ⁺ ion donor can also be an acidic salt, generating HsO ⁺ ions under the preparation conditions.

According to one embodiment, the at least one HsO ⁺ ion donor is a strong acid having a pK _a of 0 or less at 20°C. According to another embodiment, the at least one HsO ⁺ ion donor is a mediumstrong acid having a pK _a value from 0 to 2.5 at 20°C. If the pK _a at 20°C is 0 or less, the acid is preferably selected from sulphuric acid, hydrochloric acid, or mixtures thereof. If the pK _a at 20°C is from 0 to 2.5, the HsO ⁺ ion donor is preferably selected from H2SO3, H3PO4, oxalic acid, or mixtures thereof. The at least one HsO ⁺ ion donor can also be an acidic salt, for example, HSC - or H2PO4; being at least partially neutralized by a corresponding cation such as Li ⁺ , Na ⁺ or K ⁺ , or HPC ^2- , being at least partially neutralised by a corresponding cation such as Li ⁺ , Na ⁺ K ⁺ , Mg ²⁺ or Ca ²⁺ . The at least one H ₃ O ⁺ ion donor can also be a mixture of one or more acids and one or more acidic salts.

According to one embodiment of the present invention, the at least one HsO ⁺ ion donor is selected from the group consisting of hydrochloric acid, sulphuric acid, sulphurous acid, phosphoric acid, oxalic acid, and mixtures thereof. Preferably the at least one HsO ⁺ ion donor is selected from the group consisting of hydrochloric acid, sulphuric acid, sulphurous acid, phosphoric acid, oxalic acid, H2PO4', being at least partially neutralised by a corresponding cation such as Li ⁺ , Na ⁺ or K ⁺ , HPC ^2- , being at least partially neutralised by a corresponding cation such as Li ⁺ , Na ⁺ K ⁺ , Mg ²⁺ , or Ca ²⁺ and mixtures thereof, more preferably the at least one acid is selected from the group consisting of hydrochloric acid, sulphuric acid, sulphurous acid, phosphoric acid, oxalic acid, or mixtures thereof, and most preferably, the at least one HsO ⁺ ion donor is phosphoric acid.

The one or more HsO ⁺ ion donor can be added to the suspension as a concentrated solution or a more diluted solution. Preferably, the molar ratio of the HsO ⁺ ion donor to the natural or precipitated calcium carbonate is from 0.01 to 4, more preferably from 0.02 to 2, even more preferably 0.05 to 1 and most preferably 0.1 to 0.58.

As an alternative, it is also possible to add the HsO ⁺ ion donor to the water before the natural or precipitated calcium carbonate is suspended.

The skilled person will appreciate that the reaction of the natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors may generate carbon dioxide in situ.

In a preferred embodiment, the HsO ⁺ ion donor treatment step is repeated at least once, more preferably several times. According to one embodiment, the at least one HsO ⁺ ion donor is added over a time period of at least about 5 min, preferably at least about 10 min, typically from about 10 to about 20 min, more preferably about 30 min, even more preferably about 45 min, and sometimes about 1 h or more. Subsequent to the HsO ⁺ ion donor 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 of greater than 6.0, preferably greater than 6.5, more preferably greater than 7.0, even more preferably greater than 7.5.

In a particular preferred embodiment the surface reacted calcium carbonate is a reaction product of natural ground calcium carbonate (GNCC) with phosphoric acid.

Further details about the preparation of the surface-reacted natural calcium carbonate are disclosed in W00039222 A1 , W02004083316 A1 , WO2005121257 A2, W02009074492 A1 , EP2264108 A1 , EP2264109 A1 and US20040020410 A1 , the content of these references herewith being included in the present application.

Similarly, surface-reacted precipitated calcium carbonate is obtained. As can be taken in detail from W02009074492 A1 , surface-reacted precipitated calcium carbonate is obtained by contacting precipitated calcium carbonate with HsO ⁺ ions and with anions being solubilized in an aqueous medium and being capable of forming water-insoluble calcium salts, in an aqueous medium to form a slurry of surface-reacted precipitated calcium carbonate, wherein said surface-reacted precipitated calcium carbonate comprises an insoluble, at least partially crystalline calcium salt of said anion formed on the surface of at least part of the precipitated calcium carbonate.

Said solubilized calcium ions correspond to an excess of solubilized calcium ions relative to the solubilized calcium ions naturally generated on dissolution of precipitated calcium carbonate by HsO ⁺ ions, where said HsO ⁺ ions are provided solely in the form of a counterion to the anion, i.e. via the addition of the anion in the form of an acid or non-calcium acid salt, and in absence of any further calcium ion or calcium ion generating source.

Said excess solubilized calcium ions are preferably provided by the addition of a soluble neutral or acid calcium salt, or by the addition of an acid or a neutral or acid non-calcium salt which generates a soluble neutral or acid calcium salt in situ.

Said HsO ⁺ ions may be provided by the addition of an acid or an acid salt of said anion, or the addition of an acid or an acid salt which simultaneously serves to provide all or part of said excess solubilized calcium ions.

In a further preferred embodiment of the preparation of the surface-reacted natural or precipitated calcium carbonate, the natural or precipitated calcium carbonate is reacted with the one or more HsO ⁺ ion donors in the presence of at least one compound selected from the group consisting of silicate, silica, aluminium hydroxide, earth alkali aluminate such as sodium or potassium aluminate, magnesium oxide, or mixtures thereof. Preferably, the at least one silicate is selected from an aluminium silicate, a calcium silicate, or an earth alkali metal silicate. These components can be added to an aqueous suspension comprising the natural or precipitated calcium carbonate before adding the one or more HsO ⁺ ion donors.

Alternatively, the silicate and/or silica and/or aluminium hydroxide and/or earth alkali aluminate and/or magnesium oxide components) can be added to the aqueous suspension of natural or precipitated calcium carbonate while the reaction of natural or precipitated calcium carbonate with the one or more HsO ⁺ ion donors has already started. Further details about the preparation of the surface- reacted natural or precipitated calcium carbonate in the presence of at least one silicate and/or silica and/or aluminium hydroxide and/or earth alkali aluminate component(s) are disclosed in W02004083316 A1 , the content of this reference herewith being included in the present application.

The surface-reacted calcium carbonate can be kept in suspension, optionally further stabilised by a dispersant. Conventional dispersants known to the skilled person can be used. A preferred dispersant is comprised of polyacrylic acids and/or carboxymethylcelluloses.

Alternatively, the aqueous suspension described above can be dried, thereby obtaining the solid (i.e. dry or containing as little water that it is not in a fluid form) surface-reacted natural or precipitated calcium carbonate in the form of granules or a powder.

The specific pore volume is measured using a mercury intrusion porosimetry measurement using a Micromeritics Autopore V 9620 mercury porosimeter having a maximum applied pressure of mercury 414 MPa (60 000 psi), equivalent to a Laplace throat diameter of 0.004 pm (~ nm). The equilibration time used at each pressure step is 20 seconds. The sample material is sealed in a 5 cm ³ chamber powder penetrometer for analysis. The data are 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, p1753-1764.).

The total pore volume seen in the cumulative intrusion data can be separated into two regions with the intrusion data from 214 pm down to about 1 - 4 pm showing the coarse packing of the sample between any agglomerate structures contributing strongly. Below these diameters lies the fine interparticle packing of the particles themselves. If they also have intraparticle pores, then this region appears bi modal, and by taking the specific pore volume intruded by mercury into pores finer than the modal turning point, i.e. finer than the bi-modal point of inflection, the specific intraparticle pore volume is defined. The sum of these three regions gives the total overall pore volume of the powder, but depends strongly on the original sample compaction/settling of the powder at the coarse pore end of the distribution.

By taking the first derivative of the cumulative intrusion curve the pore size distributions based on equivalent Laplace diameter, inevitably including pore-shielding, are revealed. The differential curves clearly show the coarse agglomerate pore structure region, the interparticle pore region and the intraparticle pore region, if present. Knowing the intraparticle pore diameter range it is possible to subtract the remainder interparticle and interagglomerate pore volume from the total pore volume to deliver the desired pore volume of the internal pores alone in terms of the pore volume per unit mass (specific pore volume). The same principle of subtraction, of course, applies for isolating any of the other pore size regions of interest.

Preferably, the surface-reacted calcium carbonate has an intra-particle intruded specific pore volume in the range from 0.1 to 2.3 cm ³ /g, more preferably from 0.2 to 2.0 cm ³ /g, especially preferably from 0.4 to 1 .8 cm ³ /g and most preferably from 0.6 to 1 .6 cm ³ /g, calculated from mercury porosimetry measurement.

The intra-particle pore size of the surface-reacted calcium carbonate preferably is in a range of from 0.004 to 1 .6 pm, more preferably in a range of from 0.005 to 1 .3 pm, especially preferably from 0.006 to 1 .15 pm and most preferably of 0.007 to 1 .0 pm, e.g. 0.008 to 0.60 pm determined by mercury porosimetry measurement.

Calciumphosphate

According to one embodiment, the mineral particles are calcium phosphate or a mixture of calcium phosphate and hydromagnesite and/or calcium carbonate.

For the purpose of the present invention, the term “calcium phosphate” refers to compounds and minerals containing calcium ions (Ca ²⁺ ) together with inorganic phosphate anions. In addition, calcium phosphates may also contain oxide ions and/or hydroxide ions. Calcium phosphates may be derived from natural resources and are found in many living organisms, e.g. in bone minerals, tooth enamel, or in colloidal form in micelles bound to the casein in milk of mammals.

Examples of suitable calcium phosphates are monocalcium phosphate (Ca(H2PC>4)), monocalcium phosphate monohydrate (Ca(H2PC>4) H2O), dicalcium phosphate (dibasic calcium phosphate, mineral: monetite) (CaHPC ), dicalcium phosphate monohydrate (CaHPCM ), dicalcium phosphate dihydrate (mineral: brushite) (CaHPC>4'2 H2O), tricalcium phosphate (tribasic calcium phosphate or tricalcic phosphate, mineral: whitlockite) (Ca3(PC>4)2), octacalcium phosphate ((CasH2(PO4)6'5 H2O), amorphous calcium phosphate, dicalcium diphosphate (Ca2P2O?), calcium triphosphate ((Cas(P30io)2), hydroxyapatite (Cas(PO4)3(OH)), apatite (Caw(PO4)6(OH, F, Cl, Br)2), tetracalcium phosphate (Ca4(PC>4)2O), and mixtures thereof. According to one embodiment the calcium phosphate is dicalcium phosphate dihydrate (mineral: brushite) (CaHPC>4'2 H2O).

Hydromagnesite

According to one embodiment, the mineral particles are hydromagnesite or a mixture of calcium carbonate and hydromagnesite and/or calcium phosphate.

Hydromagnesite or basic magnesium carbonate, which is the standard industrial name for hydromagnesite, is a naturally occurring mineral which is found in magnesium rich minerals such as serpentine and altered magnesium rich igneous rocks, but also as an alteration product of brucite in periclase marbles. Hydromagnesite is described as having the following formula Mgs(CO3)4(OH)2 ■

4 H2O.

It should be appreciated that hydromagnesite is a very specific mineral form of magnesium carbonate and occurs naturally as small needle-like crystals or crusts of acicular or bladed crystals. In addition thereto, it should be noted that hydromagnesite is a distinct and unique form of magnesium carbonate and is chemically, physically and structurally different from other forms of magnesium carbonate. Hydromagnesite can readily be distinguished from other magnesium carbonates by x-ray diffraction analysis, thermogravimetric analysis or elemental analysis. Unless specifically described as hydromagnesite, all other forms of magnesium carbonates (e.g. artinite (Mg2(CC>3)(OH)2 ■ 3 H2O), dypingite (Mgs(CO3)4(OH)2 ■ 5 H2O), giorgiosite (Mgs(CO3)4(OH)2 ■ 5 H2O), pokrovskite (Mg2(CC>3)(OH)2 ■ 0.5 H2O), magnesite (MgCOs), barringtonite (MgCOs ■ 2 H2O), lansfordite (MgCOs ■

5 H2O) and nesquehonite (MgCOs ■ 3 H2O)) are not hydromagnesite within the meaning of the present invention and do not correspond chemically to the formula described above.

Besides the natural hydromagnesite, precipitated hydromagnesite (or synthetic magnesium carbonate) can be prepared. For instance, US1361324, US935418, GB548197 and GB544907 generally describe the formation of aqueous solutions of magnesium bicarbonate (typically described as “Mg(HCC>3)2”), which is then transformed by the action of a base, e.g., magnesium hydroxide, to form hydromagnesite. Other processes described in the art suggest to prepare compositions containing both, hydromagnesite and magnesium hydroxide, wherein magnesium hydroxide is mixed with water to form a suspension which is further contacted with carbon dioxide and an aqueous basic solution to form the corresponding mixture (cf. for example US5979461).

It is appreciated that the hydromagnesite can be one type or a mixture of different types of hydromagnesite. In one embodiment of the present invention, the hydromagnesite comprises, preferably consists of, one type of hydromagnesite. Alternatively, the hydromagnesite comprises, preferably consists of, two or more types of hydromagnesites.

According to a preferred embodiment, the hydromagnesite is precipitated hydromagnesite.

Surface treatment of mineral particles

The mineral particles may be non-surface treated mineral particles or may be surface-treated with a surface treatment agent. According to one embodiment the mineral particles are surface-treated with a surface treatment agent or are a blend of surface-treated mineral particles and non-surface treated mineral particles. The surface treatment may further improve the surface characteristics and especially may increase the affinity between the mineral particles and the infusing liquid composition, which may further improve the compatibility of the mineral particles with the infusing liquid composition or further components of the inventive composition, and may further stabilize the contained liquid layer. For example, if the infusing liquid composition is a hydrophobic material, using mineral particles being surface-treated with a hydrophobic surface treatment agent can increase the stability of the contained liquid layer compared to the use of non-surface treated mineral particles.

A “surface-treatment agent” in the meaning of the present invention is any material, which is capable of reacting and/or forming an adduct with the surface of the mineral particles, thereby forming a surface-treatment layer on at least a part of the surface of the mineral particles. It should be understood that the present invention is not limited to any particular surface-treatment agents. The skilled person knows how to select suitable materials for use as surface-treatment agents. However, it is preferred that the surface-treatment agents are selected from unsaturated and/or saturated surfacetreatment agents.

The surface treatment agent may be selected from the group consisting of mono- or disubstituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

According to one embodiment, the surface-treatment agent is selected from the group consisting of

I) a phosphoric acid ester blend of one or more phosphoric acid mono ester and/or salts thereof and/or one or more phosphoric acid di-ester and/or salts thereof, or

II) at least one saturated or unsaturated aliphatic linear or branched carboxylic acid and/or salts thereof, preferably at least one aliphatic carboxylic acid having a total amount of carbon atoms from C4 to C24 and/or a salt thereof, more preferably at least one aliphatic carboxylic acid having a total amount of carbon atoms from C12 to C20 and/or a salt thereof, most preferably at least one aliphatic carboxylic acid having a total amount of carbon atoms from C16 to C18 and/or a salt thereof, or

III) at least one mono-substituted succinic anhydride consisting of succinic anhydride mono-substituted with a group selected from a linear, branched, aliphatic and cyclic group having a total amount of carbon atoms from at least C2 to C30 in the substituent and/or salts thereof, or

IV) at least one polydialkylsiloxane, in particular carboxylic acid- and/or anhydride- functional, or

V) at least one cross-linkable compound comprising at least two functional groups, wherein at least one functional group is suitable for cross-linking a polymer resin and wherein at least one functional group is suitable for reacting with the precipitated calcium carbonate, or

VI) at least one grafted polymer comprising at least one succinic anhydride group obtained by grafting maleic anhydride onto a homo- or copolymer comprising butadiene units and optionally styrene units and/or salty reaction products thereof, or

VII) at least one functionalized poly- and/or perfluorinated compound, or

VII) mixtures of one or more materials according to I) to VI).

For the purpose of the present invention, the term “reaction products” of the surface-treatment agent refers to products obtained by contacting the mineral particles with the at least one surfacetreatment agent. Said reaction products are formed between at least a part of the applied surfacetreatment agent and reactive molecule sites located at the surface of the mineral particle.

According to one embodiment of the present invention, the mineral particles comprises a surface-treatment layer on at least a part of the mineral particlessurface, wherein the surface-treatment layer is formed by contacting the mineral particles with at least one surface-treatment agent in an amount from 0.07 to 9 mg/m ² of the mineral particlesurface, preferably 0.1 to 8 mg/m ² , more preferably from 0.11 to 3 mg/m ² , and wherein the at least one surface treatment agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

The term “at least one” surface treatment agent in the meaning of the present invention means that the surface treatment agent comprises, preferably consists of, one or more surface treatment agent(s).

In one embodiment of the present invention, the at least one surface treatment agent comprises, preferably consists of, one surface treatment agent. Alternatively, the at least one surface treatment agent comprises, preferably consists of, two or more surface treatment agents. For example, the at least one surface treatment agent comprises, preferably consists of, two or three surface treatment agents. Preferably, the at least one surface treatment agent comprises, more preferably consists of, one surface treatment agent.

The at least one surface treatment agent can be a mono- or di-substituted succinic anhydride containing compound and/or a mono- or di-substituted succinic acid containing compound and/or a mono- or di-substituted succinic acid salt containing compound.

The term “succinic anhydride containing compound” refers to a compound containing succinic anhydride. The term “succinic anhydride”, also called dihydro-2, 5-furandione, succinic acid anhydride or succinyl oxide, has the molecular formula C4H4O3 and is the acid anhydride of succinic acid.

The term “mono-substituted” succinic anhydride containing compound in the meaning of the present invention refers to a succinic anhydride wherein a hydrogen atom is substituted by another substituent.

The term “di-substituted” succinic anhydride containing compound in the meaning of the present invention refers to a succinic anhydride wherein two hydrogen atoms are substituted by another substituent.

The term “succinic acid containing compound” refers to a compound containing succinic acid. The term “succinic acid” has the molecular formula C4H6O4.

The term “mono-substituted” succinic acid in the meaning of the present invention refers to a succinic acid wherein a hydrogen atom is substituted by another substituent.

The term “di-substituted” succinic acid containing compound in the meaning of the present invention refers to a succinic acid wherein two hydrogen atoms are substituted by another substituent.

The term “succinic acid salt containing compound” refers to a compound containing succinic acid, wherein the active acid groups are partially or completely neutralized. The term “partially neutralized” succinic acid salt containing compound refers to a degree of neutralization of the active acid groups in the range from 40 and 95 mole-%, preferably from 50 to 95 mole-%, more preferably from 60 to 95 % and most preferably from 70 to 95 %. The term “completely neutralized” succinic acid salt containing compound refers to a degree of neutralization of the active acid groups of > 95 mole-%, preferably of > 99 mole-%, more preferably of > 99.8 mole-% and most preferably of 100 mole-%. Preferably, the active acid groups are partially or completely neutralized.

The succinic acid salt containing compound is preferably a compound selected from the group consisting of sodium, potassium, calcium, magnesium, lithium, strontium, primary amine, secondary amine, tertiary amine and/or ammonium salts thereof, whereby the amine salts are linear or cyclic. It is appreciated that one or both acid groups can be in the salt form, preferably both acid groups are in the salt form.

The term “mono-substituted” succinic acid salt in the meaning of the present invention refers to a succinic acid salt wherein a hydrogen atom is substituted by another substituent.

The term “di-substituted” succinic acid containing compound in the meaning of the present invention refers to a succinic acid salt wherein two hydrogen atoms are substituted by another substituent.

Accordingly, the mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds or mono- or di-substituted succinic acid salts containing compounds comprise substituent(s) R ¹ and/or R ² . It is appreciated that surface treatment agent located on the surface of the surface-treated calcium carbonate are suitable for undergoing a reaction with a material surrounding the surface- treated calcium carbonate. Thus, it is preferred that the mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds or mono- or di- substituted succinic acid salts containing compounds comprise substituent(s) R ¹ and/or R ² comprising a crosslinkable double bond.

The crosslinkable double bond is located terminally and/or in a side chain of substituent(s) R ¹ and/or R ² .

The substituent(s) R ¹ and/or R ² comprising a crosslinkable double bond is/are preferably selected from an isobutylene, a polyisobutylene, an acryloyl, a methacryloyl group or mixtures thereof.

For example, the surface treatment agent is a polyisobutylene succinic anhydride having a Brookfield viscosity at 25°C in the range from 1 000 to 300 000 mPa s. Additionally or alternatively, the surface treatment agent is a polyisobutylene succinic anhydride having an acid number in the range from 10 to 80 mg potassium hydroxide per g polyisobutylene succinic anhydride.

Preferably, the surface treatment agent is a polyisobutylene succinic anhydride having a Brookfield viscosity at 25°C in the range from 1 000 to 300 000 mPa s and an acid number in the range from 10 to 80 mg potassium hydroxide per g polyisobutylene succinic anhydride.

In one embodiment, the surface treatment agent is a maleinized polybutadiene having a Brookfield viscosity at 25°C in the range from 1 000 to 300 000 mPa s, and/or an acid number in the range from 10 to 300 mg potassium hydroxide per g maleinized polybutadiene and/or an iodine number in the range from 100 to 1 000 g iodine per 100 g maleinized polybutadiene. For example, the surface treatment agent is a maleinized polybutadiene having a Brookfield viscosity at 25°C in the range from 1 000 to 300 000 mPa s, or an acid number in the range from 10 to 300 mg potassium hydroxide per g maleinized polybutadiene or an iodine number in the range from 100 to 1 000 g iodine per 100 g maleinized polybutadiene. Alternatively, the surface treatment agent is a maleinized polybutadiene having a Brookfield viscosity at 25°C in the range from 1 000 to 300 000 mPa s, and an acid number in the range from 10 to 300 mg potassium hydroxide per g maleinized polybutadiene and an iodine number in the range from 100 to 1 000 g iodine per 100 g maleinized polybutadiene.

The term “maleinized” means that the succinic anhydride is obtained after reaction of substituent(s) R ¹ and/or R ² comprising a crosslinkable double bond with the double bond of maleic anhydride.

It is preferred that the mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds or mono- or di-substituted succinic acid salts containing compounds comprises substituent R ¹ only. Accordingly, said compound is preferably a mono- substituted succinic anhydride containing compound, mono- substituted succinic acid containing compound or mono- substituted succinic acid salt containing compound comprising substituent R ¹ .

According to a preferred embodiment the mono- or di-substituted succinic anhydride containing compound is a maleinized polybutadiene.

Additionally or alternatively, the at least one surface treatment agent is selected from saturated fatty acids and/or salts of saturated fatty acids. The term "saturated fatty acid" in the meaning of the present invention refers to straight chain or branched chain, saturated organic compounds composed of carbon and hydrogen. Said organic compound further contains a carboxyl group placed at the end of the carbon skeleton.

In one embodiment, the saturated fatty acid is selected from saturated unbranched carboxylic acids, preferably selected from the group of carboxylic acids consisting of pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosylic acid, behenic acid, tricosylic acid, lignoceric acid and mixtures thereof, and preferably, the saturated fatty acid is selected from the group consisting of myristic acid, palmitic acid, stearic acid, and mixtures thereof.

Additionally or alternatively, the at least one surface treatment agent is selected from unsaturated fatty acids and/or salts of unsaturated fatty acids.

The term "unsaturated fatty acid" in the meaning of the present invention refers to straight chain or branched chain, unsaturated organic compounds composed of carbon and hydrogen. Said organic compound further contains a carboxyl group placed at the end of the carbon skeleton.

The unsaturated fatty acid is preferably selected from the group consisting of myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, a-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid and mixtures thereof. More preferably, the surface treatment agent being an unsaturated fatty acid is selected from the group consisting of myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, a-linolenic acid and mixtures thereof. Most preferably, the surface treatment agent being an unsaturated fatty acid is oleic acid and/or linoleic acid, preferably oleic acid or linoleic acid, most preferably linoleic acid.

Additionally or alternatively, the surface treatment agent is a salt of a saturated or unsaturated fatty acid.

The term “salt of saturated or unsaturated fatty acid” refers to a saturated or unsaturated fatty acid, wherein the active acid group is partially or completely neutralized. The term “partially neutralized” saturated or unsaturated fatty acid refers to a degree of neutralization of the active acid groups in the range from 40 and 95 mole-% preferably from 50 to 95 mole-%, more preferably from 60 to 95 mole-% and most preferably from 70 to 95 mole-%. The term “completely neutralized” saturated or unsaturated fatty acid refers to a degree of neutralization of the active acid groups of > 95 mole-%, preferably of > 99 mole-%, more preferably of > 99.8 mole-% and most preferably of 100 mole-%. Preferably, the active acid groups are partially or completely neutralized.

The salt of saturated or unsaturated fatty acid is preferably a compound selected from the group consisting of sodium, potassium, calcium, magnesium, lithium, strontium, primary amine, secondary amine, tertiary amine and/or ammonium salts thereof, whereby the amine salts are linear or cyclic. For example, the surface treatment agent is a salt of oleic acid and/or linoleic acid, preferably oleic acid or linoleic acid, most preferably linoleic acid.

Additionally or alternatively, the at least one surface treatment agent is an unsaturated ester of phosphoric acid and/or a salt of an unsaturated phosphoric acid ester. Thus, the unsaturated ester of phosphoric acid may be a blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester and optionally one or more phosphoric acid triester. In one embodiment, said blend further comprises phosphoric acid.

For example, the unsaturated ester of phosphoric acid is a blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester. Alternatively, the unsaturated ester of phosphoric acid is a blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester and phosphoric acid. Alternatively, the unsaturated ester of phosphoric acid is a blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester and one or more phosphoric acid tri-ester. Alternatively, the unsaturated ester of phosphoric acid is a blend of one or more phosphoric acid mono-ester and one or more phosphoric acid di-ester and one or more phosphoric acid tri-ester and phosphoric acid.

For example, said blend comprises phosphoric acid in an amount of < 8 mol.-%, preferably of < 6 mol.-%, and more preferably of < 4 mol.-%, like from 0.1 to 4 mol.-%, based on the molar sum of the compounds in the blend.

The term "phosphoric acid mono-ester" in the meaning of the present invention refers to an o-phosphoric acid molecule mono-esterified with one alcohol molecule selected from unsaturated, branched or linear, aliphatic or aromatic alcohols having a total amount of carbon atoms from C6 to C30, preferably from C8 to C22, more preferably from C8 to C20 and most preferably from C8 to C18 in the alcohol substituent.

The term "phosphoric acid di-ester" in the meaning of the present invention refers to an o- phosphoric acid molecule di-esterified with two alcohol molecules selected from the same or different, unsaturated, branched or linear, aliphatic or aromatic alcohols having a total amount of carbon atoms from C6 to C30, preferably from C8 to C22, more preferably from C8 to C20 and most preferably from C8 to C18 in the alcohol substituent.

The term "phosphoric acid tri-ester" in the meaning of the present invention refers to an o- phosphoric acid molecule tri-esterified with three alcohol molecules selected from the same or different, unsaturated, branched or linear, aliphatic or aromatic alcohols having a total amount of carbon atoms from C6 to C30, preferably from C8 to C22, more preferably from C8 to C20 and most preferably from C8 to C18 in the alcohol substituent.

Additionally or alternatively, the surface treatment agent is a salt of an unsaturated phosphoric acid ester. In one embodiment, the salt of an unsaturated phosphoric acid ester may further comprise minor amounts of a salt of phosphoric acid.

The term “salt of unsaturated phosphoric acid ester” refers to an unsaturated phosphoric acid ester, wherein the active acid group(s) is/are partially or completely neutralized. The term “partially neutralized” unsaturated phosphoric acid esters refers to a degree of neutralization of the active acid group(s) in the range from 40 and 95 mole-%, preferably from 50 to 95 mole-%, more preferably from 60 to 95 mole-% and most preferably from 70 to 95 mole-%. The term “completely neutralized” unsaturated phosphoric acid esters refers to a degree of neutralization of the active acid group(s) of > 95 mole-%, preferably of > 99 mole-%, more preferably of > 99.8 mole-% and most preferably of 100 mole-%. Preferably, the active acid group(s) is/are partially or completely neutralized. The salt of unsaturated phosphoric acid ester is preferably a compound selected from the group consisting of sodium, potassium, calcium, magnesium, lithium, strontium, primary amine, secondary amine, tertiary amine and/or ammonium salts thereof, whereby the amine salts are linear or cyclic.

According to one embodiment of the present invention the surface-treated mineral particles have a hydrophobicity of below 2.3:1 volumetric ratio of waterethanol measured at +23°C (± 2°C) with the sedimentation method. For example, the surface-treated mineral particles have a hydrophobicity of below 2.2:1 , preferably of below 2.1 :1 and most preferably of below 2.0:1 volumetric ratio of waterethanol measured at +23°C (± 2°C) with the sedimentation method. For example the surface- treated mineral particles have a hydrophobicity of 1 .9:1 volumetric ratio of waterethanol measured at +23°C (± 2°C) with the sedimentation method. Most preferably, the surface-treated mineral particles have a hydrophobicity in the range of 1 :1 to 1 .9:1 volumetric ratio of waterethanol measured at +23°C (± 2°C) with the sedimentation method.

Methods for the surface treatment of mineral particles are known to the skilled person, and are described, for example, in EP 3 192 837 A1 , EP 2 770 017 A1 , and WO 2016/023937. According to one embodiment, the surface-treated mineral particles of the present invention are obtainable by a process comprising the following steps:

A) providing an aqueous suspension of at least one mineral particles having solids content in the range from 5 to 80 wt.-%, based on the total weight of the aqueous suspension;

B) optionally adjusting the pH-value of the aqueous suspension of step A) to a range from 7.5 to 12;

C) adding at least one surface treatment agent to the aqueous suspension obtained in step B) in an amount ranging from 0.07 to 9 mg/m ² of the mineral particle surface, preferably 0.1 to 8 mg/m ² , more preferably from 0.11 to 3 mg/m ² of the particle surface, wherein the at least one surface treatment agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds; saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids; unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters; maleic anhydride functionalized polybutadiene, mixtures thereof, or a combination thereof;

D) mixing the aqueous suspension obtained in step C) at a temperature in the range from 30 to 120°C;

E) drying the aqueous suspension during or after step D) at a temperature in the range from 40 to 160°C at ambient or reduced pressure until the moisture content of the obtained surface-treated mineral particles is in the range from 0.001 to 20 wt.-%, based on the total weight of the surface-treated mineral particles; and

F) adding at least one base to the aqueous suspension of step C) to readjust the pH-value to the range from 7.5 to 12 during or after step d); and/or

G) deagglomerating the surface-treated mineral particles of step D) or E) after or during step E). According to another embodiment, the mineral particles do not comprise a surface-treatment layer, i.e. untreated mineral particles are employed in the inventive method, the inventive surface-modified material, the inventive article, the inventive use, or the inventive kit, respectively.

Binder

According to the present invention, the coating composition further comprises a binder, preferably in an amount from 1 to 50 wt.-%, based on the total weight of the mineral particles, preferably from 3 to 30 wt.-%, more preferably from 5 to 15 wt.-%, and most preferably from 8 to 10 wt.-%.

The binder can be selected from any material or combination of materials that is capable of binding the mineral particles to the substrate and forming a porous coating layer with the mineral particles. Moreover, the skilled person would appreciate that the binder should be selected from a material that does not dissolve in the subsequently applied infusing liquid composition. The most appropriate binder may vary depending on the particular application.

For example, in case the binder is in form of particles, e.g. in form of a latex, the size of the particles may be selected such that particles cannot enter the pores or do not block the pores of the mineral particles. According to one embodiment, the particles size of the binder is larger than the pore size of the mineral particles, preferably by at least 5%, more preferably at least 10%, and most preferably at least 20%. According to another embodiment, the particles size of the binder is smaller than the pore size of the mineral particles, preferably by at least 5%, more preferably at least 10%, and most preferably at least 20%.

Alternatively, a film forming binder may be used, which would not be restricted with respect to the particle size.

Any suitable polymeric binder may be used in the liquid coating composition of the invention. For example, the polymeric binder may be a hydrophilic polymer such as, for example, polyvinyl alcohol, polyvinyl pyrrolidone, gelatine, cellulose ethers, polyoxazolines, polyvinylacetamides, partially hydrolyzed polyvinyl acetate/vinyl alcohol, polyacrylic acid, polyacrylamide, polyalkylene oxide, sulfonated or phosphated polyesters and polystyrenes, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodian, agar-agar, arrowroot, guar, carrageenan, starch, tragacanth, xanthan, rhamsan, or mixtures thereof. It is also possible to use other binders such as hydrophobic materials, for example, poly(styrene-co-butadiene), latex, polyurethane latex, polyester latex, poly(n- butyl acrylate), poly(n-butyl methacrylate), poly(2-ethylhexyl acrylate), copolymers of n-butylacrylate and ethylacrylate, copolymers of vinylacetate and n-butylacrylate, or mixtures thereof. Further examples of suitable binders are homopolymers or copolymers of acrylic and/or methacrylic acids, itaconic acid, and acid esters, such as e.g. ethylacrylate, butyl acrylate, styrene, unsubstituted or substituted vinyl chloride, vinyl acetate, ethylene, butadiene, acrylamides and acrylonitriles, silicone resins, water dilutable alkyd resins, acrylic/alkyd resin combinations, natural oils such as linseed oil, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, cellulose nitrate, styrene-acrylic copolymers, vinyl acetate-ethylene copolymers, vinyl acetate-acrylic copolymers, vinyl acetate-vinyl versatate copolymers, ambient and/or UV-crosslinking acrylic polymers, natural rubber latex, modified natural rubber latex, methyl methacrylate, polyvinyl acetate, formaldehyde-based binders, protein binders, gum arabic, turpentine, drying oil, bee wax, polyacrylate, vinyl-chloride copolymers, polyisocyanates, alkyd resins, phenolic resins, epoxy resins, rosin, or mixtures thereof.

According to one embodiment the binder is selected from the group consisting of polyolefins, polyvinyl alcohol, polyvinyl pyrrolidone, gelatine, cellulose ethers, polyoxazolines, polyvinylacetamides, partially hydrolyzed polyvinyl acetate/vinyl alcohol, polyacrylic acid, polyacrylamide, polyalkylene oxide, sulfonated or phosphated polyesters and polystyrenes, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodian, agar-agar, arrowroot, guar, carrageenan, starch, tragacanth, xanthan, rhamsan, poly(styrene-co-butadiene), latex, polyurethane latex, polyester latex, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, poly(n-butyl acrylate), poly(n-butyl methacrylate), poly(2-ethylhexyl acrylate), copolymers of n-butylacrylate and ethylacrylate, copolymers of vinylacetate and n-butylacrylate, homopolymers or copolymers of acrylic and/or methacrylic acids, itaconic acid, and acid esters, ethyl acrylate, butyl acrylate, styrene, unsubstituted or substituted vinyl chloride, vinyl acetate, ethylene, butadiene, acrylamides and acrylonitriles, silicone resins, water dilutable alkyd resins, acrylic/alkyd resin combinations, natural oils such as linseed oil, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, cellulose nitrate, bio-based latex, styrene-acrylic copolymers, vinyl acetate-ethylene copolymers, vinyl acetate-acrylic copolymers, vinyl acetate-vinyl versatate copolymers, ambient and/or UV-crosslinking acrylic polymers, natural rubber latex, modified natural rubber latex, methyl methacrylate, polyvinyl acetate, formaldehyde-based binders, protein binders, gum arabic, turpentine, drying oil, bee wax, polyacrylate, vinyl-chloride copolymers, polyisocyanates, alkyd resins, phenolic resins, epoxy resins, rosin, or mixtures thereof.

According to one embodiment the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, preferably the binder is selected from the group consisting of styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, and most preferably the binder is a styrene-acrylate latex.

The types of mineral particles and binder and the concentration of the binder will be dependent on the compatibility between the binder and the mineral particles being used and may vary for any given system.

Further components

Other optional additives that may be present in the coating composition are, for example, dispersants, milling aids, surfactants, rheology modifiers, lubricants, defoamers, optical brighteners, dyes, preservatives, or pH controlling agents. According to one embodiment, the coating layer further comprises a rheology modifier. Preferably the rheology modifier is present in an amount of less than 2 wt.-%, based on the total weight of the mineral particles.

The composition can further include one or more additives such as a surfactant, a film-forming agent, a pH adjustor, a colorant, a pigment, a suspending agent, a dispersant, a wetting agent, a defoaming agent, an anti-oxidant, a UV- absorber or UV-stabilizer, a leveling agent, a stabilizing agent, a chemical modifier, and a catalyst. In some embodiments, an additive can be used to further increase desired surface character (e.g. hydrophobic or hydrophilic character). The pigment may be selected from any organic pigment or inorganic pigment known to the skilled person. Examples of suitable inorganic pigments are iron oxide, chromium oxide, graphite, zinc oxide, zinc sulphide, or titanium oxide. According to one embodiment, the coating composition comprises a pigment, preferably an inorganic pigment, more preferably titanium dioxide, and most preferably surface-treated titanium dioxide.

According to one embodiment, the mineral particles are dispersed with a dispersant. The dispersant may be used in an amount from 0.01 to 10 wt.-%, 0.05 to 8 wt.-%, 0.5 to 5 wt.-%, 0.8 to 3 wt.-%, or 1 .0 to 2 wt.-%, based on the total weight of the mineral particles. In a preferred embodiment, the mineral particles are dispersed with an amount of 0.05 to 5 wt.-%, and preferably with an amount of 0.5 to 5 wt.-% of a dispersant, based on the total weight of the mineral particles. A suitable dispersant is preferably selected from the group comprising homopolymers or copolymers of polycarboxylic acid salts based on, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid and acrylamide or mixtures thereof. Homopolymers or copolymers of acrylic acid are especially preferred. The molecular weight M _w of such products is preferably in the range of 2000 to 15000 g/mol, with a molecular weight M _w of 3000 to 7000 g/mol being especially preferred. The molecular weight M _w of such products is also preferably in the range of 2000 to 150000 g/mol, and an Mw of 15000 to 50 000 g/mol is especially preferred, e.g., 35000 to 45000 g/mol. According to an exemplary embodiment, the dispersant is polyacrylate.

Method step c)

According to step c) of the method of the present invention, an infusing liquid composition is provided, wherein the infusing liquid composition is chemically inert to the substrate and the porous coating layer obtained in step d) of the method of the present invention.

The infusing liquid composition may be selected from a number of different liquids. The liquid may be either a pure liquid, a mixture of liquids, a solution of solid compounds in a solvent, or a complex fluid comprising liquid and solid components such as a lipid emulsions. The infusing liquid composition can also be a molten substance of mixture of compounds.

Depending on the envisaged application field of the surface-modified material, the infusing liquid composition may be hydrophobic or hydrophilic.

According to one embodiment, the infusing liquid composition is a hydrophobic infusing liquid composition. According to one embodiment the hydrophobic infusing liquid composition is a fluorinated hydrocarbon, an organosilicone compound, a long-chain hydrocarbon, or a mixture thereof.

Examples of suitable fluorinated hydrocarbons are fluorocarbon polymers, tertiary perfluoroalkyl amines, preferably perfluorotri-n-pentylamine, perfluorotri-n-burylamine, perfluoroalkylsulfides, perfluoroalkylsulfoxides, perfluoroalkylethers, perfluorocycloethers, perfluoropolyethers, e.g. Krytox™ lubricants (commercially available from The Chemours Company), or Fomblin® lubricants (commercially available from Solvay Speciality Polymers), perfluoroalkylphosphines, perfluoroalkylphosphineoxides, long-chain perfluorinated carboxylic acids, perferably perfluorooctadecanoic acid, fluorinated phosphonic acid, fluorinated sulfonic acids, fluorinated silanes, or mixtures thereof. According to one embodiment, the fluorinated hydrocarbon is selected from the group comprising functionalized poly- and/or perfluoropolyethers having at least one functional group, preferably at least one terminal functional group, more preferably at least one terminal functional group selected from the group comprising a carboxyl group, a phosphate ester group, a hydroxy group, their salts, derivatives and mixtures thereof, and is most preferably selected from the group comprising poly(hexafluoropropylene oxide)s having a terminal carboxyl group located on the terminal fluoromethylene group thereof, or a bifunctional perfluoropolyether ammonium phosphate salt, poly- and/or perfluorocarboxylic acids, preferably perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid, perfluorooctane sulfonate (PFOS), perfluorooctane sulfonamide (PFOSA), perfluorobutane sulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), heptafluorobutyric acid (HFBA), their salts, derivatives and mixtures thereof. One preferred group of fluorinated hydrocarbons is the group of colourless synthetic lubricants (oils and greases) marketed under the trademark Krytox™, which are fluorocarbon ether polymers of polyhexafluoropropylene oxide, with a chemical formula: F-(CF(CF3)-CF2-O) _n -CF2CF3, wherein n = 10 - 60, which may be functionalized by a terminal functional group, e.g. Krytox™ 157FS(L) and Krytox™ 157FS(H), which are poly(hexafluoropropylene oxide) functionalized with a carboxylic acid group situated on the terminal fluoromethylene group having molecular weights of about 2500 and 7000 - 7500 g/mol, respectively.

Examples of suitable organosilicone compounds are silicone oil, linear or branched polydimethylsiloxane (PDMS), e.g. Siltech silicone lubricants (commercially available from Siltech Corporation), polydiethylsiloxane (PDES), methyltris(trimethoxysiloxy)silane, phenyl -T- branched polysilsexyquioxane, copolymers of side-group functionalized polysiloxanes, e.g. Pecosil® silicone lubricants (commercially available from Phoenix Chemical, Inc.), or mixtures thereof.

Examples of suitable long-chain hydrocarbons are C15 or higher alkyl petroleum oils, paraffin oils, linear or branched paraffins, cyclic paraffins, aromatic hydrocarbons, alkenyl succinic anhydrides, petroleum jelly, waxes, raw vegetable oils, modified vegetable oils, glycerides, fatty acids, or mixtures thereof. Examples of suitable waxes are animal waxes, plant waxes such as carnuba wax, paraffin waxes, or mixtures thereof. Examples of vegetable oils are canola oil, coconut oil, olive oil, soybean oil, or mixtures thereof.

According to another embodiment the infusing liquid composition is a hydrophilic infusing liquid composition. According to one embodiment the hydrophilic infusing liquid composition is an aqueous solution, a diol, a triol, a hydrophilic hydrocarbon, a hydrophilic silicone, or a mixture thereof.

Examples of suitable aqueous solutions are water or mixtures of water with at least one water- miscible organic solvent, preferably methanol, ethanol, acetone, glycerol, acetonitrile, tetrahydrofuran, ethylene glycol, propylene glycol, and mixtures thereof.

Example of suitable hydrophilic hydrocarbons are hydrocarbons functionalised with aldehyde, amide, amine, and/or hydroxyl groups.

Examples of suitable hydrophilic silicones are (hydroxyalkyl functional) methylsiloxanedimethylsiloxane copolymers, dodecylmethylsiloxane-hydroxypolyalkyleneoxypropylmethylsilo xane copolymer, or mixtures thereof.

Examples of suitable diols are ethane- 1 ,2-diol, propane-1 ,2-diol, butane- 1 ,4-diol, or mixtures thereof. An examples of a suitable triol is glycerol.

According to one embodiment the infusing liquid composition is selected from the group consisting of a fluorinated hydrocarbon, an organosilicone compound, a long-chain hydrocarbon, an aqueous solution, a hydrophilic hydrocarbon, a hydrophilic silicone, a diol, a triol, and a mixture thereof, preferably the liquid treatment composition is selected from the group consisting of fluorocarbon polymers, tertiary perfluoroalkyl amines, preferably perfluorotri-n-pentylamine, perfluorotri-n-burylamine, perfluoroalkylsulfides, perfluoroalkylsulfoxides, perfluoroalkylethers, perfluorocycloethers, perfluoropolyethers, perfluoroalkylphosphines, perfluoroalkylphosphineoxides, long-chain perfluorinated carboxylic acids, preferably perfluorooctadecanoic acid, fluorinated phosphonic acid, fluorinated sulfonic acids, fluorinated silanes, linear or branched polydimethylsiloxane (PDMS), polydiethylsiloxane (PDES), methyltris(trimethoxysiloxy)silane, phenyl - T- branched polysilsexyquioxane, copolymers of side-group functionalized polysiloxanes, C15 or higher alkyl petroleum oils, paraffin oils, linear or branched paraffins, cyclic paraffins, aromatic hydrocarbons, alkenyl succinic anhydrides, petroleum jelly, waxes, raw vegetable oils, modified vegetable oils, glycerides, fatty acids, water, mixtures of water with at least one water-miscible organic solvent, preferably methanol, ethanol, glycerol, acetone, acetonitrile, tetrahydrofuran, ethylene glycol, propylene glycol, and mixtures thereof, hydrocarbons functionalised with aldehyde, amide, amine, and/or hydroxyl groups, (hydroxyalkyl functional) methylsiloxane-dimethylsiloxane copolymers, dodecylmethylsiloxane-hydroxypolyalkyleneoxypropyl-methylsil oxane copolymer, ethane- 1 ,2-diol, propane-1 ,2-diol, glycerol, and mixtures thereof.

According to one embodiment, the infusing liquid composition is derived from renewable sources and/or is non-toxic. Examples of such materials are lipids, vegetable oils, preferably olive oil, corn oil, soybean oil, rapeseed oil, linseed oil, grapeseed oil, flaxseed oil, peanut oil, safflower oil, palm oil, coconut oil, or sunflower oil, fats, plant exudates such as gums and resins, fatty acids, derivatives of vegetable oils or fatty acids, esters, terpenes, monoglycerides, diglycerides, triglycerides, alcohols, fatty acid alcohols, water, and mixtures thereof.

According to a preferred embodiment, the infusing liquid composition is selected from the group consisting of a vegetable oil, a silicone oil, glycerol, fatty acids, and mixtures thereof.

According to one embodiment the infusing liquid composition is a hydrophobic infusing liquid composition, preferably selected from the group consisting of a fluorinated hydrocarbon, an organosilicone compound, a long-chain hydrocarbon, or a mixture thereof, more preferably selected from the group consisting of fluorocarbon polymers, tertiary perfluoroalkyl amines, preferably perfluorotri-n-pentylamine, perfluorotri-n-burylamine, perfluoroalkylsulfides, perfluoroalkylsulfoxides, perfluoroalkylethers, perfluorocycloethers, perfluoropolyethers, perfluoroalkylphosphines, perfluoroalkylphosphineoxides, long-chain perfluorinated carboxylic acids, preferably perfluorooctadecanoic acid, fluorinated phosphonic acid, fluorinated sulfonic acids, fluorinated silanes, linear or branched polydimethylsiloxane (PDMS), polydiethylsiloxane (PDES), methyltris(trimethoxysiloxy)silane, phenyl -T- branched polysilsexyquioxane, copolymers of side-group functionalized polysiloxanes, C15 or higher alkyl petroleum oils, paraffin oils, linear or branched paraffins, cyclic paraffins, aromatic hydrocarbons, alkenyl succinic anhydrides, petroleum jelly, waxes, raw vegetable oils, modified vegetable oils, glycerides, fatty acids, and mixtures thereof.

According to another embodiment the infusing liquid composition is a hydrophilic infusing liquid composition, preferably a solution selected from the group consisting of an aqueous solution, a diol, a triol, a hydrophilic hydrocarbon, a hydrophilic silicone, and a mixture thereof, more preferably selected from the group consisting of water, mixtures of water with at least one water-miscible organic solvent, preferably methanol, ethanol, glycerol, acetone, acetonitrile, tetrahydrofuran, ethylene glycol, propylene glycol, and mixtures thereof, hydrocarbons functionalised with aldehyde, amide, amine, and/or hydroxyl groups, (hydroxyalkyl functional) methylsiloxane-dimethylsiloxane copolymers, dodecylmethylsiloxane-hydroxypolyalkyleneoxypropylmethylsilo xane copolymer, ethane- 1 ,2-diol, propane-1 ,2-diol, glycerol, and mixtures thereof, more preferably selected from the group consisting of water and mixtures of water with at least one water-miscible organic solvent, preferably methanol, ethanol, glycerol, acetone, acetonitrile, tetrahydrofuran, ethylene glycol, propylene glycol, and mixtures thereof, and most preferably the hydrophilic solution is a mixture of water and glycerol.

Other examples of suitable infusing liquid compositions are ionic liquids, eutectic solvents, or azeotropic liquids.

According to one embodiment of the present invention, the infusing liquid composition is a mixture of water and alcohol, preferably methanol, ethanol, glycerol, and mixtures thereof. Preferably the weight ratio of water : alcohol may be from 10:1 to 1 :10, preferably from 5:1 to 1 :5, more preferably from 2:1 to 1 :2, and most preferably about 1 :1.

The infusing liquid composition may comprise further additional compounds. According to one embodiment, the infusing liquid composition comprises one or more active agents, dyes, odorants, metal ions, nano particles, dispersants, surfactants, pH buffers, corrosion inhibitors, salts, or mixtures thereof.

According to one embodiment the one or more active agent(s) is/are an antimicrobial agent, an antiviral agent, a biocide, a preservative, a pesticide, preferably an insecticide, an UV protecting agent, or a mixture thereof.

Examples of suitable antimicrobial agents are 5-chloro-2-(2,4-dichlorophenoxy)-phenol (triclosan), chlorhexidine, alexidine, hexetidine, sanguinarine, benzalkonium chloride, salicylamide, domiphen bromide, cetylpyridinium chloride (CPC), tetradecyl pyridinium chloride (TPC), N-tetradecyl- 4-ethyl pyridinium chloride (TDEPC), octenidine, delmopinol, octapinol, and other piperidino derivatives, niacin preparations, botanicals such as essential oils, zinc/stannous ion agents, antibiotics such as augmentin, amoxycillin, tetracycline, doxycyline, minocycline, and metronidazole, and analogues, derivatives and salts of the above antimicrobial agents and mixtures thereof.

Examples of suitable biocides are glutardialdehyde (GDA), isothiazolinones such as 2-methyl- 2H-isothiazol-3-one (MIT), 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT), benzisothiazolinone (BIT), octyl-isothiazolinone (OIT), 4,5-dichloro-2-n-octyl-4-isothiazol-3-one (DCOIT), 2-bromo-2-nitro-1 ,3- propandiol (bronopol), 2,2-dibromo-3-nitrilopropionamide (DBNPA), o-phenylphenol (OPP) and its salts, phenoxyethanol, formaldehyde, ethyleneglycolhemiformals, 1-(3-chloroallyl)-3,5,7-Triaza-1- azoniaadamantane chloride, tetrakishydroxymethyl phosphonium sulfate (THPS), 4,4- dimethyloxazolidine (DMO), hexahydro-1 ,3,5-tris(2-hydroxyethyl)-s-triazine, hexahydro-1 ,3,5-triethyl-s- triazine (HTT), tetrahydro-3, 5-dimethyl-2H-1 ,3, 5-thiadiazine-2-thione (DAZOMET), 3-iodo-2-propynyl butyl carbamate (IPBC), 5-chloro-2-(2,4-dichlorophenoxy)-phenol (triclosan); and derivatives, salts and mixtures thereof. According to one embodiment, the biocide is an algicide, preferably selected from the group consisting of benzalkonium chloride, bethoxazin, copper sulfate, cybutryne, dichlone, dichlorophen, diuron, endothal, fentin, lime, isoproturon, methabenzthiazuron, nabam, oxyfluorfen, pentachlorophenyl laurate, quinoclamine, quinonamid, simazine, terbutryn, tiodonium, and mixtures thereof.

Examples of suitable preservatives are sodium pyrosulphite, butylhydroxytoluene, butylated hydroxyanisole, parabenes, benzalkonium chloride, chlorbutanol, benzyl alcohol, beta-phenylethyl alcohol, cetylpyridinium chloride, citric acid, tartaric acid, lactic acid, malic acid, acetic acid, benzoic acid, and sorbic acid and their salts; and chelating agents, such as EDTA; and gallates, such as propyl gallate.

Examples of suitable pesticides are herbicide, insecticide, insect growth regulator, nematicide, termiticide, molluscicide, piscicide, avicide, rodenticide, predacide, bactericide, insect repellent, animal repellent, antimicrobial, fungicide, disinfectant (antimicrobial), and sanitizer known to the skilled person. According to a preferred embodiment, the pesticide is an insecticide.

Examples of suitable UV protecting agents are titanium dioxide, zinc oxide, benzophenone derivatives, bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), drometrizole trisiloxane (Meroxyl XL), terephthalylidene dicamphor sulfonic acid (Mexoryl SX), ethylhexyl triazone (Uvinul T 150), butyl methoxydibenzoylmethane (Avobenzone), diethylamino hydroxybenzoyl hexyl benzoate (Uvinul A Plus), diethylhexyl butamido triazone (Iscotrizinol), phenylbenzimidazole sulfonic acid (Enzulisol) and mixtures thereof.

Examples of other materials that may be present in the infusing liquid composition are pheromones, biological messenger molecules, antifouling agents, tribologic actives, humectants, hygroscopic agents, flame retardants, anti-freeze agents, or mixtures thereof.

According to one embodiment, the infusing liquid comprises a biocide, preferably 2-methyl-2H- isothiazol-3-one (MIT), benzisothiazolinone (BIT), or a mixture thereof. According to a preferred embodiment, the infusing liquid comprises a mixture of water and alcohol, preferably methanol, ethanol, glycerol, and mixtures thereof, wherein the weight ratio of water : alcohol is from 10:1 to 1 :10, preferably from 5:1 to 1 :5, more preferably from 2:1 to 1 :2, and most preferably about 1 :1 , and a biocide, preferably 2-methyl-2H-isothiazol-3-one (MIT), benzisothiazolinone (BIT), or a mixture thereof.

It is common knowledge in the art that the surface tension of a liquid should be below the surface free energy of the solid surface, on which it is placed, in order to achieve a wetting and/or infusing of the solid surface. Therefore, the skilled person will select the infusing liquid composition such that its surface tension is below the surface free energy of the porous coating layer so that it can infuse into the porous coating layer. The surface free energy of the porous coating layer may be determined by contact angle measurements. The surface tension of the infusing liquid may also be determined by contact angle measurement. Alternatively, the surface tension may be determined by any other method known in the art, e.g. the Wilhelmy plate method, the spinning drop method, or Du Noliy ring method.

Whether a selected infusing liquid composition is capable of infusing the formed porous coating layer can be also examined by placing a drop of the infusing liquid composition onto the porous coating layer and measuring the contact angle between the surface of the infusing liquid composition and the outline of the contact surface of the porous coating layer. If the contact angle is smaller than 90° sufficient infusion may occur, while at contact angles above 90° no infusion may take place. Suitable methods and devices for measuring contact angles are known in the art. For example, the optical contact angle measuring device OCA 50 (DataPhysics Instruments GmbH) may be used.

According to one embodiment the contact angle between the surface of the infusing liquid composition and the outline of the contact surface of the porous coating layer is less than 90°, preferably less than 60°, more preferably less than 45°, and most preferably less than 25°. According to one embodiment, the infusing liquid composition is selected such that the application of 20 pl of infusion liquid composition onto the porous coating layer results in the formation of a drop having a contact angle between the surface of the infusing liquid composition and the outline of the contact surface of the porous coating layer of less than 90°, preferably less than 60°, more preferably less than 45°, and most preferably less than 25°.

According to one embodiment the infusing liquid composition has a surface tension from 1 to 72 mN/m at 20°C, preferably from 5 to 60 mN/m at 20°C, more preferably from 10 to 50 mN/m at 20°C, and most preferably from 15 to 40 mN/m at 20°C, measured by an optical contact angle measuring device in pedant drop set up using the Young-Laplace calculation method for drop contour fitting.

According to one embodiment the infusing liquid composition has a viscosity from 1 to 1450 mPa s at 20°C, preferably from 2 to 1000 mPa s at 20°C, more preferably from 5 to 500 mPa s at 20°C, even more preferably from 8 to 300 mPa s at 20°C, and most preferably from 10 to 100 mPa s at 20°C.

In addition or alternatively, the infusing liquid composition may have a standard boiling point of at least 100°C, preferably of at least 150°C, more preferably at least 200°C, and most preferably at least 290°C.

According to one embodiment, the infusing liquid composition has a high density, preferably a density of more than 0.7 g/cm ³ , more preferably more than 1 g/cm ³ , even more preferably more than 1 .6 g/cm ³ , and most preferably more than 1 .9 g/cm ³ .

According to a further embodiment, the infusing liquid composition has a low freezing temperature, preferably a freezing temperature of less than -5°C, more preferably less than -15 °C, even more preferably less than -25°C, and most preferably less than -40 °C. Selecting an infusing liquid composition having a low freezing temperature may allow the infusing liquid composition to maintain its properties at reduced temperatures and may be especially advantageous for anti-icing applications.

The infusing liquid composition may have a low vapour pressure in order to minimize evaporation of the infusing liquid composition after it has been infused into the porous coating layer. According to one embodiment the liquid treatment composition has a vapour pressure of less than 1000 Pa at 20°C, preferably less than 900 Pa at 20°C, more preferably less than 800 Pa at 20°C, and most preferably less than 700 Pa at 20°C.

According to a further embodiment, the infusing liquid has a low evaporation rate, preferably an evaporation rate of less than 1 nm/s, more preferably less than 0.1 nm/s, and most preferably less than 0.01 nm/s of the thickness of the liquid treatment composition per a given area at 20°C. The evaporation rate may be determined by an evaporimeter or by simply measuring the weight of the sample over time or by any other suitable method known to the skilled person. In case the infusing liquid composition is an aqueous solution a humectant may be added to keep the evaporation rate low. A “humectant” in the meaning of the present invention is a hygroscopic substance, which can attract and retain water molecules from the surrounding environment via absorption and/or adsorption. In contrast to a desiccant, which removes water molecules, a humectant promotes retention of moisture.

Examples of suitable humectants are glycerine, sorbitol, xylitol, maltitol, propylene glycol, butylene glycol, polyethylene glycol, hexylene glycol, sodium pyroglutamic aicd, alpha-hydroc acids, glyceryl triacetate, lithium chloride, or a deliquescent salt. The term “deliquescent salt” as used herein refers to a salt that has a high affinity for moisture and can collect gaseous water molecules from the atmosphere to form a mixture of the solid salt and liquid water, or an aqueous solution of the salt, until the substance is dissolved (cf. definition of “deliquescence”, IUPAC, Compendium of Chemical Terminology Goldbook, version 2.3.3, 2014). Non-limiting examples of a “deliquescent salt” are magnesium chloride, calcium chloride, iron chloride, copper chloride, zinc chloride, aluminium chloride, magnesium bromide, calcium bromide, iron bromide, copper bromide, zinc bromide, aluminium bromide, magnesium iodide, calcium iodide, magnesium nitrate, calcium nitrate, iron nitrate, silver nitrate, zinc nitrate, aluminium nitrate, magnesium acetate, calcium acetate, iron acetate, copper acetate, zinc acetate or aluminium acetate.

According to one embodiment, the infusing liquid composition comprises a humectant, preferably the humectant is selected from the group consisting of glycerine, sorbitol, xylitol, maltitol, propylene glycol, butylene glycol, polyethylene glycol, hexylene glycol, sodium pyroglutamic acid, alpha-hydroc acids, glyceryl triacetate, lithium chloride, a deliquescent salt, and mixtures thereof, more preferably the humectant is selected from the group consisting of glycerine, sorbitol, xylitol, maltitol, propylene glycol, butylene glycol, polyethylene glycol, hexylene glycol, sodium pyroglutamic aicd, alpha-hydroc acids, glyceryl triacetate, lithium chloride, magnesium chloride, calcium chloride, iron chloride, copper chloride, zinc chloride, aluminium chloride, magnesium bromide, calcium bromide, iron bromide, copper bromide, zinc bromide, aluminium bromide, magnesium iodide, calcium iodide, magnesium nitrate, calcium nitrate, iron nitrate, silver nitrate, zinc nitrate, aluminium nitrate, magnesium acetate, calcium acetate, iron acetate, copper acetate, zinc acetate, aluminium acetate, and mixtures thereof, and most preferably the humectant is glycerine.

According to one embodiment, the infusing liquid composition has a standard boiling point of at least 280°C, preferably about 209°C, a vapour pressure from 500 to 800 Pa at 20°C, preferably about 660 mm Hg at 20°C, a freezing temperature of less than - 40°C, preferably about - 50°C, a surface tension from 15 to 25 mN/m at 20°C, preferably about 18 mN/m at 20°C, and a density of more than 0.7 g/cm ³ , preferably of about 1 g/cm ³ . Preferably said infusing liquid is a hydrophobic infusing liquid. The surface tension was measured by an optical contact angle measuring device in pedant drop set up using the Young-Laplace calculation method for drop contour fitting.

According to another embodiment, the infusing liquid composition has a standard boiling point of at least 280°C, preferably about 209°C, a vapour pressure from 0.6 to 7 Pa at 20°C, preferably about 1 .3 Pa at 20°C, a freezing temperature of less than - 25°C, preferably about - 38°C, a surface tension from 15 to 72 mN/m at 20°C, preferably about 58 mN/m at 20°C, and a density of more than 1 g/cm ³ , preferably of about 1.26 g/cm ³ . Preferably said infusing liquid is a hydrophilic infusing liquid. The surface tension was measured by an optical contact angle measuring device in pedant drop set up using the Young-Laplace calculation method for drop contour fitting.

According to one embodiment, the infusing liquid composition is an aqueous solution comprising a humectant, and has a standard boiling point of at least 280°C, preferably about 209°C, a vapour pressure from 0.6 to 7 Pa at 20°C, preferably about 1 .3 Pa at 20°C, a freezing temperature of less than - 25°C, preferably about - 38°C, a surface tension from 15 to 72 mN/m at 20°C, preferably about 58 mN/m at 20°C, and a density of more than 1 g/cm ³ , preferably of about 1 .26 g/cm ³ . The surface tension was measured by an optical contact angle measuring device in pedant drop set up using the Young-Laplace calculation method for drop contour fitting.

Method step d)

According to step d) of the method of the present invention, the coating composition of step b) is applied onto at least one surface of the substrate of step a) and the applied coating composition is dried to form a porous coating layer on the at least one surface of the substrate,

The coating composition may be applied onto the at least one surface of the substrate by conventional coating means commonly used in this art. Suitable coating methods are, e.g., air knife coating, electrostatic coating, metering size press, film coating, spray coating, wound wire rod coating, slot coating, slide hopper coating, gravure, curtain coating, high speed coating and the like. Some of these methods allow for simultaneous coatings of two or more layers, which is preferred from a manufacturing economic perspective. However, any other coating method which would be suitable to form a coating layer on the substrate may also be used. According to an exemplary embodiment, the coating composition is applied by high speed coating, metering size press, curtain coating, spray coating, flexo and gravure, or blade coating, and preferably curtain coating.

The coating composition may be applied in any suitable amount and thickness. The skilled person will adapt the applied amount of the coating composition to the solids content of the coating composition, the substrate, and the envisaged application.

According to one embodiment, the coating composition is applied onto the at least one surface of the substrate in an amount sufficient to yield a coating weight of the porous coating layer from 5 to 400 g/m ² , preferably from 7 to 300 g/m ² , more preferably from 9 to 200 g/m ² , and most preferably from 10 to 150 g/m ² . For example, the coating composition is applied onto the at least one surface of the substrate in an amount sufficient to yield a coating weight of the porous coating layer from 5 to 100 g/m ² , preferably from 6 to 80 g/m ² , more preferably from 7 to 60 g/m ² , even more preferably from 8 to 40 g/m ² , and most preferably from 9 to 30 g/m ² . According to a further example, the coating composition is applied onto the at least one surface of the substrate in an amount sufficient to yield a coating weight of the porous coating layer from 20 to 400 g/m ² , preferably from 40 to 350 g/m ² , more preferably from 60 to 250 g/m ² , even more preferably from 80 to 200 g/m ² , and most preferably from 90 to 150 g/m ² .

According to another embodiment, the coating composition is applied onto the at least one surface of the substrate in an amount sufficient to yield a wet coating thickness of at least 10 pm, preferably at least 50 pm, more preferably at least 100 pm, even more preferably at least 150 pm, and most preferably at least 300 pm. According to step d), the applied coating composition is dried. The drying can be carried out by any method known in the art, and the skilled person will adapt the drying conditions such as the temperature according to his process equipment. For example, the coating composition can be dried by infrared drying and/or convection drying. The drying step may be carried out at room temperature, i.e. at a temperature of 20°C ± 2°C or at other temperatures. According to one embodiment, the drying is carried out at substrate surface temperature from 25 to 150°C, preferably from 50 to 140°C, and more preferably from 75 to 130°C. Optionally applied precoating layers and/or barrier layers can be dried in the same way.

According to one embodiment, method step d) is also carried out on the reverse surface of the substrate to manufacture a substrate being coated on the first and the reverse side. These steps may be carried out for each side separately or may be carried out on the first and the reverse side simultaneously.

According to one embodiment of the present invention, method step d) is carried out two or more times using a different or the same coating composition.

The inventors surprisingly found that the application of a coating composition according to the present invention onto a substrate results in a porous coating layer having voids and cavities which can immobilize or contain the infusing liquid composition effectively. In contrast to the methods of the prior art, which often require a complex, multistep texturization of the substrate surface, the method of the present invention provides the possibility to create the porous coating layer by a single application step. In other words, the present invention provides a one-pot coating composition that can be applied onto the substrate by conventional coating methods to provide a porous coating layer capable of holding and stabilizing, i.e. immobilizing, locking, or containing, an infusing liquid composition within and on the porous coating layer to form a liquid-infused porous coating layer. Furthermore, the coating composition employed in the inventive method comprises mineral fillers, which are non-toxic, biodegradable and can be obtained from natural resources.

The porous coating layer formed on the at least one surface of the substrate by the inventive method is capable of immobilizing or containing the infusing liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer. According to one embodiment the porosity of the porous coating layer is selected such that at least 150 wt.-%, based on the total weight of the porous coating, of the infusing liquid composition is immobilized within and on the porous coating layer.

As noted above, the porosity of the porous coating layer can be tailored by the selection of the mineral particles and the binder.

According to one embodiment, the porous coating layer comprises the mineral particles in an amount from 75 to 95 wt.-%, preferably 80 to 90 wt.-%, based on the total weight of the porous coating layer, and the binder in an amount from 25 to 5 wt.-%, preferably 20 to 10 wt.-%, based on the total weight of the porous coating layer.

According to a further embodiment, the porous coating layer comprises the mineral particles in an amount from 75 to 90 wt.-%, based on the total weight of the porous coating layer, the binder in an amount from 25 to 8 wt.-%, based on the total weight of the porous coating layer, and dispersant in an amount from 1 to 2 wt.-%. According to one embodiment, the porous coating layer has a coat weight from 5 to 400 g/m ² , preferably from 7 to 300 g/m ² , more preferably from 9 to 200 g/m ² , and most preferably from 10 to 150 g/m ² . For example, the porous coating layer has a coat weight from 5 to 100 g/m ² , preferably from 6 to 80 g/m ² , more preferably from 7 to 60 g/m ² , even more preferably from 8 to 40 g/m ² , and most preferably from 9 to 30 g/m ² . According to a further example, the porous coating layer has a coat weight from 20 to 400 g/m ² , preferably from 40 to 350 g/m ² , more preferably from 60 to 250 g/m ² , even more preferably from 80 to 200 g/m ² , and most preferably from 90 to 150 g/m ² .

According to another embodiment, the porous coating layer has a dry coating thickness of at least 5 pm, preferably at least 10 pm, more preferably at least 50 pm, even more preferably at least 100, and most preferably at least 150 pm.

According to one embodiment the porous coating layer has a maximum roughness PSq from 1 to 4 pm, preferably from 1 .1 to 3.5 pm, more preferably from 1 .2 to 3 pm, and most preferably from 1 .2 to 2.9 pm, determined by confocal microscopy. In addition or alternatively, the porous coating layer has a waviness WSq from 0.2 to 6 pm, preferably from 0.3 to 5.8 pm, more preferably from 0.4 to 5.5 pm, and most preferably from 0.4 to 5.2, determined by confocal microscopy. In addition or alternatively, the porous coating layer has a total intruded pore volume in the range from 0.2 to 1.1 cm ³ /g, preferably from 0.25 to 1 cm ³ /g, more preferably from 0.3 to 0.95 cm ³ /g, and most preferably from 0.31 to 0.9 cm ³ /g, measured by mercury intrusion porosimetry.

Roughness and waviness are surface textures well-known in the art to characterize the surface texture of a coating layer. While the “roughness” focuses on the finer structures in the surface texture, the “waviness” relates to irregularities whose spacing is greater than the roughness sampling length. Methods to determine roughness and waviness of a coating layer are known in the art. According to one embodiment the roughness PSq and the waviness WSq are determined by confocal microscopy, wherein a stack of micrographs at different height-levels is recorded, and a Gauss-filter (ISO 16610-71) with a threshold of 16 pm was applied to separate roughness from waviness, wherein roughness and waviness were then calculated by the following equation:

According to one embodiment the porous coating layer has an intra particle intruded specific pore volume in the range from 0.05 to 0.8 cm ³ /g, preferably from 0.1 to 0.5 cm ³ /g.

In addition or alternatively, the porous coating layer has an inter particle intruded specific pore volume in the range from 0.05 to 0.6 cm ³ /g, preferably from 0.1 to 0.5 cm ³ /g.

In addition or alternatively, the porous coating layer has an agglomerated intruded pore volume in the range from 0.04 to 0.4 cm ³ /g, preferably 0.05 to 0.2 cm ³ /g.

According to one embodiment, the surface gloss G20 of the surface-modified material is increased by at least 0.5 %, compared to the surface gloss G20 of same surface-modified material without the contained liquid layer within and on the porous coating layer. According to one embodiment, the surface gloss G20 of the of the surface-modified material is increased by at least 0.6%, preferably by at least 1 %, more preferably by at least 1 .4%, and most preferably by at least 2%, compared to the surface gloss G20 of same surface-modified material without the contained liquid layer within and on the porous coating layer. For example, the difference value between the surface gloss G20 of the of the surface-modified material and the surface gloss G20 of same surface-modified material without the contained liquid layer within and on the porous coating layer may be from 0.5 to 2.5%, preferably 0.6 to 2.2%, more preferably from 0.7 to 2.1%, and most preferably from 0.8 to 2%. The surface gloss G20 is measured with a polarized light reflectometer at a nominal 20° acceptance angle. Suitable devices are known to the skilled person, e.g., the Surfoptic Imaging Reflectometer System (SIRS 75, or SIRS 75/M), Dayta Systems Ltd. May be used. According to one embodiment, the evaluation of the sample is done on a surface area of 40x40 mm with a mapping mesh of 25 knots, the knots were located 10 mm away from the each other in x and y direction, the values were recorded, and the arithmetic average was calculated.

As noted above, the porous coating layer obtained by the inventive method can contain or immobilize a large amount of the infusing liquid composition. According to one embodiment, the porous coating layer has an infusion capacity of at least 5 g/m ² , preferably at least 10 g/m ² , more preferably at least 20 g/m ² , and most preferably at least 30 g/m ² . The infusion capacity may be measured at 23°C and 50% relative humidity by dipping a weighted sample of a substrate comprising a porous coating layer into a reservoir of an infusing liquid composition until the porous coating layer is saturated. The skilled person will appreciate that the time required for saturation may depend on the viscosity of the infusing liquid composition as well as the nature of the infusing liquid composition and the surface characteristics of the porous coating layer, and may be, e.g., less than 1 s, less than 30 s, less than 1 min, at least 1 min, at least 5 min, at least 15 min, at least 30 min, or at least 1 h.

According to a further aspect of the present invention, use of a substrate comprising a porous coating layer for containing an infusing liquid composition which is chemically inert to the substrate and the porous coating layer is provided, wherein the porous coating layer is in contact with at least one surface of the substrate, the porous coating layer comprises a mineral filler selected from the group consisting of calcium carbonate, hydromagnesite, and mixtures thereof, and a binder, and the porous coating layer is capable of containing the infusing liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to one embodiment, the porous coating layer is a hydrophobic porous coating layer.

Method step e)

According to step e) of the method of the present invention, the porous coating layer obtained in step d) is infused with at least 150 wt.-%, based on the total weight of the porous coating layer, of the infusing liquid composition of step c) to form a contained liquid layer within and on the porous coating layer. Thus, the porous coating layer immobilizes or contains the infusing liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer obtained by step d).

According to one embodiment step e) is carried out until the porous coating layer is saturated, preferably step e) is carried out for at least 1 min or at least 5 min, preferably at least 15 min, more preferably at least 30 min, even more preferably at least 1 h, still more preferably at least 2 h, and most preferably at least 4 h. The skilled person will appreciate that the duration of step e) may depend on the viscosity of the infusing liquid composition as well as the nature of the infusing liquid composition and the surface characteristics of the porous coating layer.

According to one embodiment the porous coating layer obtained in step d) is infused with at least 200 wt.-%, preferably at least 250 wt.-%, more preferably at least 300 wt.-%, and most preferably at least 350 wt.-%, based on the total weight of the porous coating layer, of the infusing liquid composition of step c) to form a contained liquid layer within and on the porous coating layer.

According to one embodiment the amount of infusing liquid composition per unit area of the porous coating layer may be from 0.5 to 500 mg/cm ² , preferably from 1 to 250 mg/cm ² , more preferably from 2 to 100 mg/cm ² , even more preferably from 3 to 75 mg/cm ² , and most preferably from 4 to 50 mg/cm ² .

By infusing the porous coating layer with the infusing liquid composition, the infusing liquid composition becomes contained within and on the porous coating layer, i.e. the infusing liquid composition is immobilized or locked within and on the porous coating layer. Said immobilization may be a result of physical attractions between the molecules of the infusing liquid composition and the surface of the mineral filler, e.g. by standard surface interactions such as van der Waals forces between the molecules of the infusing liquid composition and the mineral filler surface, by donoracceptor interactions such as e.g. hydrogen bonding between the molecules of the infusing liquid composition and the mineral filler surface, or by capillary action retaining the molecules of the infusing liquid composition in the cavities and pores on or within the mineral filler particles of the porous coating layer. A prerequisite for this mechanism is that the surface free energy of the porous coating layer is higher than the surface free energy, also called the surface tension of the infusing liquid composition. This may be manifested by a contact angle of the infusing liquid composition and the surface of the porous coating layer, which is less than 90°, preferably less than 60°, more preferably less than 40°, even more preferably less than 20°, still more preferably less than 10°, and most preferably about 0°.

A special case is when the infusing liquid composition has no hydrogen bonding properties but should be stable against aqueous liquids from outside which are able to establish hydrogen bonding to the mineral surface resulting in a displacement, and expellation of the infused liquid. In this case, it would be preferred that the coating composition comprises surface-treated mineral particles, wherein the mineral particles have been surface-treated with a hydrophobic surface treatment agent, preferably selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids; unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

Alternatively, the porous coating layer may be hydrophobic porous coating layer, preferably obtained by f) providing a liquid hydrophobising composition, and g) applying the liquid hydrophobising composition onto at least one surface of the porous coating layer obtained in step d), and drying the applied liquid hydrophobising composition to form a hydrophobic porous coating layer, wherein steps f) and g) are carried out after step d) and before step e).

Without being bound to any theory, it is believed that the hydrophobic surface-treatment can prevent the establishment of donor-acceptor interactions (e.g. hydrogen bonds) between the porous coating layer and the aqueous liquid, so that the water molecules in the aqueous liquid loose their competitive advantage and cannot longer displace the hydrophobic contained liquid layer.

In other words, the porous coating layer forms a porous matrix and the infusing liquid composition is infused into the pores of said matrix.

The contained liquid layer obtained by the inventive method, is distinct from just coating the top surface of a coating layer comprising mineral particles. In the present invention the infusing liquid composition penetrates between the mineral particles of the porous coating layer which results in a higher contact area between the surface of the mineral particles and the infusing liquid composition and, consequently, in an improved attachment of the infusing liquid composition within and on the porous coating layer as compared to a conventional coating composition that would only coat the top surface of the porous coating layer.

The contained liquid layer obtained by the inventive method, is distinct from a conventional coating layer having a solid surface because the effective surface is a liquid with all its advantages due to its mobility within the porous coating and the mobility of its functional components. Advantages of the contained liquid layer are, e.g., that it is non-stickable, it can refurbished, additional components may be added during it’s lifetime, and it is self-healing due to its mobility.

The infusing liquid composition may be infused into the porous coating layer by any suitable method known to the skilled person. For example, step e) may be carried out by dip coating, blade coating, roller coating, spraying, curtain coating, or pipetting.

According to one embodiment, step e) is carried out by dip coating, blade coating, roller coating, spraying, curtain coating, pipetting, or combinations thereof, preferably by dip coating and/or spraying.

The skilled person will select the appropriate method of infusing the infusing liquid composition based on the viscosity of the infusing liquid composition. Infusing liquids compositions having a low viscosity, e.g. a viscosity below 100 mPa s at 20°C, may be applied by dip coating or spraying at room temperature (e.g. at 20°C ± 2°C), whereas infusing liquid compositions having a higher viscosity, such as waxes, may be applied by dip coating or spraying at higher temperatures, e.g. at temperatures of up to 80°C, in order to reduce the viscosity of the liquid coating composition.

According to one embodiment, step e) is carried out two times, or more. In case the substrate comprises a porous coating layer on the first surface and the reverse surface, method step e) is also carried out on the reverse side of the substrate to manufacture a substrate being coated on the first and the reverse side. These steps may be carried out for each side separately or may be carried out on the first and the reverse side simultaneously.

Method steps f) and g)

According to a further embodiment of the present invention, the method of manufacturing a surface-modified material further comprises the steps of f) providing a liquid hydrophobising composition, and g) applying the liquid hydrophobising composition onto at least one surface of the porous coating layer obtained in step d), and drying the applied liquid hydrophobising composition to form a hydrophobic porous coating layer, wherein steps f) and g) are carried out after step d) and before step e).

The liquid hydrophobising composition comprises, preferably, consists of at least one hydrophobising agent. Suitable hydrophobising agents are known to the skilled person and may be, for example, mono- or di-substituted succinic anhydride containing compounds, mono- or disubstituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

The liquid hydrophobising composition can be in form of a solution or an emulsion. According to one embodiment of the present invention, the liquid hydrophobising composition is in form of a solution comprising the at least one hydrophobising agent, and optionally, at least one solvent. Suitable solvents are known to the skilled person and may be select, for example, from acetone, butanone, di-ethyl ketone, methanol, ethanol, isopropanol, esters such as benzyl benzoate, bis(2-ethylhexyl) adipate, bis(2-ethylhexyl) phthalate, 2-butoxyethanol acetate, butyl acetate, sec-butyl acetate, tert-butyl acetate, diethyl carbonate, dimethyl adipate, dioctyl terephthalate, ethyl acetate, ethyl acetoacetate, ethyl butyrate, ethyl lactate, ethylene carbonate, hexyl acetate, isoamyl acetate, isobutyl acetate, isopropyl acetate, methyl acetate, methyl lactate, methyl phenylacetate, methyl propionate, propyl acetate, propylene carbonate, triacetin, pentane, hexane, benzene, heptane, toluene, 1 ,4-dioxane, diethyl ether, tetrahydrofuran, chloroform, or mixtures thereof.

According to another embodiment, the liquid hydrophobising composition is in form of an aqueous emulsion, i.e. a composition comprising the at least one hydrophobising agent, water, and optionally an emulsifier. Examples of suitable emuslifiers are potassium laurate, triethanolamine stearate, sodium lauryl sulfate, alkyl polyoxyethylene sulfates, sodium dodecyl sulfate, dioctyl sodium sulfosuccinate, quaternary ammonium compounds, cetyltrimethyllammonium bromide, lauryldimethylbenzylammonium chloride, polyoxyethylene fatty acid derivatives of sorbitan esters (e.g. Tween series), polyoxyethylene fatty alcohol ethers, sorbitan fatty acid esters, polyoxyethylene alkyl ethers (macrogols), polyoxyethylene sorbitan fatty acid esters, polyoxyethylene polyoxypropylene block copolymers (poloxamers), polyethylene glycol 400 monostearate, lanolin alcohols, ethoxylated lanolin, poly(meth)acrylic acids, carboxymethylcelluloses, or mixtures thereof.

According to one embodiment, the liquid hydrophobising composition comprises, preferably, consists of at least one hydrophobising agent, wherein the at least one hydrophobising agent is selected from the group consisting of mono- or di-substituted succinic anhydride containing compounds, mono- or di-substituted succinic acid containing compounds, mono- or di-substituted succinic acid salts containing compounds, saturated or unsaturated fatty acids, salts of saturated or unsaturated fatty acids, unsaturated esters of phosphoric acid, salts of unsaturated phosphoric acid esters, maleic anhydride functionalized polybutadiene, mixtures thereof and reaction products thereof.

The liquid hydrophobising composition may be applied onto at least one surface of the porous coating layer by any suitable method know to the skilled person. According to one embodiment the liquid hydrophobising composition is applied by dip coating, blade coating, roller coating, spraying, curtain coating, brushing, painting, or pipetting.According to step g), the applied liquid hydrobobising composition is dried. The drying can be carried out by any method known in the art, and the skilled person will adapt the drying conditions such as the temperature according to his process equipment and the nature of the hydrophobising composition. For example, the liquid hydrophobising composition can be dried by infrared drying and/or convection drying. The drying step may be carried out at room temperature, i.e. at a temperature of 20°C ± 2°C. Alternatively, for example in case of water-based hydrophobising compositions, the drying may be carried out at substrate surface temperature from 25 to 150°C, preferably from 50 to 140°C, and more preferably from 75 to 130°C.

According to one embodiment of the present invention, method step g) is carried out two or more times using a different or the same liquid hydrophobising composition.

The surface-modified material

According to a further aspect of the present invention, a surface-modified material is provided comprising a substrate comprising at least one surface, a porous coating layer comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, wherein the porous coating layer is in contact with the at least one surface of the substrate, and a contained liquid layer within and on the porous coating layer, wherein the contained liquid layer is chemically inert to the substrate and the porous coating layer, and the contained liquid layer is present in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to still a further aspect of the present invention, a kit of parts for preparing a surface-modified material is provided, the kit of parts comprising a substrate comprising at least one surface, a coating composition for forming a porous coating layer on the at least one surface of the substrate, wherein the coating composition comprises mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, and an infusing liquid composition, optionally a liquid hydrophobising composition, wherein the porous coating layer is capable of containing the infusing liquid composition in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer, and wherein the infusing liquid composition is chemically inert to the substrate and the porous coating layer.

In contrast to hydrophobic or superhydrophobic surfaces, the surface-modified materials of the present invention consist of a liquid film that is contained, i.e. locked in place, by the porous coating layer. The inventors of the present invention found that the liquid surface of the contained liquid layer is smooth and defect-free. The contained liquid layer may be basically incompressible and can repel immiscible liquids. The surface-modified materials of the present invention may be characterized by a high liquid repellency and a low contact angle hysteresis.

The water contact angle (WCA) on the surface-modified material of the present invention may be measured with the sessile drop method. In this method a droplet of liquid is placed on the solid surface and a 2-dimensional image of the droplet is analyzed via the geometry of the droplet. The liquid droplet placed on a surface shows 2 boundaries with the interface solid/liquid/vapor which are the points of interest. When the droplet placed on the surface is not perturbated by any other force, then this angle is known as the static angle (0). Dynamic measurement can be done with this method and the variation used for this experiment is the tilt of the stage where the droplet is placed on the desired surface until the drop moves. In this set up the 2 boundaries show upper limit, advancing angle (0adv) , and lower limit, receding angle (0 _re c). The contact angle hysteresis can be calculated from the subtraction of the 0adv-0rec

The slippery nature of a surface may be described according to the ease by which liquid droplets move on the surface, which can be defined by the contact angle hysteresis of the droplets. Droplets that have a low contact angle hysteresis move more easily on a surface than droplets that have a high contact angle hysteresis.

According to one embodiment, water droplets which are placed on the surface of the surface- modified material of the present invention exhibit a contact angle hysteresis of less than 75°, preferably less than 70°, more preferably less than 60°C, even more preferably less than 50, and most preferably less than 35°. In addition or alternatively, water droplets which are placed on the surface of the surface-modified material of the present invention may have tilt angles of less than 90°, preferably less than 80°, more preferably less than 70°, even more preferably less than 60°, and most preferably less than 50°.

According to one embodiment of the present invention, the contained liquid layer is hydrophobic. Thus, a surface-modified material having a hydrophobic surface is provided comprising a substrate comprising at least one surface, a porous coating layer comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, wherein the porous coating layer is in contact with the at least one surface of the substrate, and a hydrophobic contained liquid layer within and on the porous coating layer, wherein the contained liquid layer is chemically inert to the substrate and the porous coating layer, and the contained liquid layer is present in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to a preferred embodiment the coating composition comprises a calcium carbonate, preferably a surface-reacted calcium carbonate, wherein the surface- reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors, wherein the calcium carbonate is surface-treated with a surface treatment agent, preferably selected from saturated or unsaturated fatty acids, the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, preferably the binder is selected from the group consisting of styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, and most preferably the binder is a styreneacrylate latex, and the infusing liquid composition is a silicon oil.

According to a further embodiment, a surface-modified material having a hydrophobic surface is provided comprising a substrate comprising at least one surface, a hydrophobic porous coating layer comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, wherein the hydrophobic porous coating layer is in contact with the at least one surface of the substrate, and a hydrophobic contained liquid layer within and on the hydrophobic porous coating layer, wherein the contained liquid layer is chemically inert to the substrate and the hydrophobic porous coating layer, and the contained liquid layer is present in an amount of at least 150 wt.-%, based on the total weight of the hydrophobic porous coating layer.

According to another embodiment of the present invention, the contained liquid layer is hydrophilic. Thus, a surface-modified material having a hydrophilic surface is provided comprising a substrate comprising at least one surface, a porous coating layer comprising mineral particles selected from the group consisting of calcium carbonate, calcium phosphate, hydromagnesite, and mixtures thereof, and a binder, wherein the porous coating layer is in contact with the at least one surface of the substrate, and a hydrophilic contained liquid layer within and on the porous coating layer, wherein the contained liquid layer is chemically inert to the substrate and the porous coating layer, and the contained liquid layer is present in an amount of at least 150 wt.-%, based on the total weight of the porous coating layer.

According to a preferred embodiment the coating composition comprises a surface-reacted calcium carbonate, wherein the surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with one or more HsO ⁺ ion donors, the binder is selected from the group consisting of starch, polyvinyl alcohol, styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, polyolefins, ethylene acrylate, microfibrillated cellulose, microcrystalline cellulose, nanocellulose, cellulose, carboxymethylcellulose, bio-based latex, and mixtures thereof, preferably the binder is selected from the group consisting of styrene-butadiene latex, styrene-acrylate latex, polyvinyl acetate latex, and most preferably the binder is a styrene- acrylate latex, and the infusing liquid composition is a solution comprising water, alcohol, and an active agent, preferably a biocide or pesticide, and more preferably an insecticide.

The surface-modified material according to the present invention is suitable for a wide range of applications. The skilled person will appropriately select the type of surface modification for the desired application. For example, the inventive surface-modified material may exhibit anti-adhesive and antifouling properties. Depending on the properties of the contained liquid layer, the inventive surface- modified material may prevent adhesion of liquids such as water, oil-based paints, hydrocarbons, organic solvents, crude oil, or protein-containing fluids. Furthermore, the surface of the inventive surface-modified material may repel solids like bacteria, insects, fungi, ice, paper, sticky notes, inorganic particle-containing paints, or dust particles.

According to one aspect of the present invention, use of a surface-modified material according to the present invention in microfluidic systems, in building applications, construction applications, fluid transport applications, anti-icing applications, anti-bacterial applications, anti-viral applications, antimold applications, pest control materials, self cleaning surfaces, self-repairing surfaces, textile production, or shoe production is provided.

According to another aspect of the present invention, an article comprising the surface- modified material according to the present invention is provided, preferably the article is selected from paper products, engineered wood products, plasterboard products, polymer products, hygiene products, medical products, healthcare products, filter products, woven materials, nonwoven materials, geotextile products, agriculture products, horticulture products, clothing, footwear products, baggage products, household products, industrial products, packaging products, building products, construction products, fluid transport products, or anti-icing products.

The scope and interest of the present invention will be better understood based on the following figures and examples which are intended to illustrate certain embodiments of the present invention and are non-limitative.

Examples

1. Materials

1.1. Mineral particles

Table 1 : Mineral particles used in the examples (SRCC: surface-reacted calcium carbonate; PHM: precipitated hydromagnesite; GCC: ground calcium carbonate; PCC: precipitated calcium carbonate).

1.2. Further materials

Table 2: Further materials used in the examples. 1.3. Preparation of precipitated hydromagnesite

Method 1

Magnesium oxide was slaked by mixing MgO with water in a MgOF weight ratio of 1 :18 to 1 :11 for 30 to 60 minutes. The obtained slaked MgO was transferred into a gas-liquid reactor and the temperature was adjusted to 50 to 70°C. Then, the slaked MgO was carbonated by introducing an air/CO2 mixture (20 vol.-% CO2). During the carbonation step, the reaction mixture was stirred with a speed of 240 rpm. The kinetic of the reaction was monitored by online pH and conductivity measurements.

The obtained precipitated hydromagnesite suspension was mechanically dewatered on a chamber filter press to a solids content from 30 to 40 wt.-%, based on the total weight of the suspension. Subsequently, the filter press cake was dried using a flash dryer with DMR technology.

The dry precipitated hydromagnesite powder had a solids content of more than 90 wt.-%, and a platy shaped rosette-like morphology.

Mineral particles P5 and P6 were manufactured by Method 1 .

Method 2

Magnesium oxide was slaked by mixing MgO with water in a MgO:H2O weight ratio of 1 :18 to 1 :11 for 30 to 60 minutes. The obtained slaked MgO was transferred into a gas-liquid reactor and the temperature was adjusted to 50 to 70°C. Then, the slaked MgO was carbonated by introducing an air/CO2 mixture (20 vol-% CO2). During the carbonation step, the reaction mixture was stirred with a speed of 60 rpm. The kinetic of the reaction was monitored by online pH and conductivity measurements.

The obtained precipitated hydromagnesite suspension was dried by a flash dryer.

The dry precipitated hydromagnesite powder had a solids content of more than 90 wt.-%, and a platy shaped rosette-like morphology.

Mineral particles P7 were manufactured by Method 2.

1.4. Coating of minerals with stearic acid and silicates

Stearic acid coating

The untreated mineral powder was placed in a mixer vessel (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and conditioned by stirring for 5 minutes at 100 - 120°C and 300 - 800 rpm, depending of the amount of mineral and the vessel used. Subsequently, the steric acid was added slowly to the mixture. Stirring and heating were then continued for another 10 to 15 minutes. After that time, the mixture was allowed to cool and the treated powder was collected.

Silicate coating

The untreated mineral powder was placed in a mixer vessel (Somakon MP-LB Mixer, Somakon Verfahrenstechnik, Germany), and TEOS (tetraethyl orthosilicate) was dosed at a concentration of 17.5 wt.-%, based on the total weight of the TEOS, at room temperature over 15 minutes, followed by stirring for 1 hour. The surface-treated material was then filtered in a Buchner funnel and dried at 125°C. Deagglomeration was conducted in a Retsch rotary impact mill. 2. Instruments

Blade: TQC Bird film applicator Width 75 mm, 50/100/150/200 pm

TQC Baker applicator 80 mm, 15/30/60/90 pm

Balance: Mettler Toledo PG6002-S DeltaRange

Pendraulik: LD 50, Nr 007494

Solid Content: Mettler Toledo HB43 - S Halogen pH-Meter: Mettler Toledo SevenEasy

Viscometer: Brookfield DV-II+, Version 4.1

Table coater: K Control Coater K 202 - Modell 624 (Erichsen)

Oven: Thermo Scientific Heraterm OMH100

Centrifuge: Hettich Rotina 420 Typ 4701

Airbrush: STARMAX SP-575 NO.U50082

Dispersing system: Nordson, 781 Mini Series Spray Valve. Automatic dosifying system.

3. Methods of characterization

3.1. Porosimetry

For porosity measurements, the coating compositions were applied onto the aluminium substrate S2. The coat weight of each sample was calculated such that the sample measurements could be represented as pore volume per gram of coating rather than the sample as a whole including the base foil as well.

A strip in a scrolled form (size: 15 cm x 2 cm) of each sample was characterised by a mercury intrusion porosimetry measurement using a Micromeritics Autopore V 9620 mercury porosimeter having a maximum applied pressure of mercury 414 MPa (60 000 psi), equivalent to a Laplace throat diameter of 0.004 pm (~ nm). The equilibration time used at each pressure step was 20 seconds. The sample material was sealed in a 5 cm ³ chamber of a penetrometer for solid sample and a 0.392 cm ³ stem volume was used for analysis. The data are 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, p 1753-1764.).

The total pore volume seen in the cumulative intrusion data can be separated into two regions with the intrusion data from 214 pm down to about 1 - 4 pm showing the coarse packing of the sample between any agglomerate structures contributing strongly. Below these diameters lies the fine interparticle packing of the particles themselves. If they also have intraparticle pores, then this region appears bi-modal, and by taking the specific pore volume intruded by mercury into pores finer than the modal turning point, i.e. finer than the bi-modal point of inflection, the specific intraparticle pore volume is defined. The sum of these three regions gives the total overall pore volume of the powder, but depends strongly on the original sample compaction/settling of the powder at the coarse pore end of the distribution.

By taking the first derivative of the cumulative intrusion curve the pore size distributions based on equivalent Laplace diameter, inevitably including pore-shielding, are revealed. The differential curves clearly show the coarse agglomerate pore structure region, the interparticle pore region and the intraparticle pore region, if present. Knowing the intraparticle pore diameter range it is possible to subtract the remainder interparticle and interagglomerate pore volume from the total pore volume to deliver the desired pore volume of the internal pores alone in terms of the pore volume per unit mass (specific pore volume). The same principle of subtraction, of course, applies for isolating any of the other pore size regions of interest.

3.2. Specific surface area (SSA)

The specific surface area was measured via the BET method according to ISO 9277:2010 using nitrogen as adsorbing gas on a Micro me ritics ASAP 2460 instrument from Micro me ritics. The samples were pre-treated in vacuum (10-5 bar) by heating at 120°C for a period of 60 min prior to measurement.

3.3. Particle size distribution

Volume determined median particle size cfeo(vol) and the volume determined top cut particle size c/9s(vol) was evaluated using a Malvern Mastersizer 3000 Laser Diffraction System (Malvern Instruments Pic., Great Britain) equipped with an Aero S accessory. The cfeo(vol) or c/9s(vol) value indicates a diameter value such that 50 % or 98 % by volume, respectively, of the particles have a diameter of less than this value. The powders were dispersed in air with a standard disperser and a pressure of 2.0 bar. Measurements were conducted with red light for 10 s. For the analysis of the raw data, the models for non-spherical particle sizes using Mie theory was utilized, and a particle refractive index of 1 .57, a density of 2.70 g/cm ³ , and an absorption index of 0.005 was assumed. The methods and instruments are known to the skilled person and are commonly used to determine particle size distributions of fillers and pigments.

3.4. Scanning electron microscope

The prepared samples were examined by a field emission scanning electron microscope (FESEM, Zeiss Sigma VP, Carl Zeiss AG) using the secondary electron detector (SE2). To show the coating structure at the cross section the micrographs were taken with the backscattered electron detector (NTS BSD). In COMPO-mode those images visualize differences in the chemical composition of a sample. The heavier the atomic weight of the elements present the brighter the particle appears in the image.

3.5. Surface topography

Confocal laser scanning microscope (CLSM) was used for reconstruction of three dimensional structures and to measure surface properties, roughness and waviness. The obtained images were analysed by applying a Roughness and Waviness A Gauss-Filter (ISO 16610-71) with a threshold of 8 pm to separate roughness from waviness.

3.6. Optical contact angle (OCA)

Equipment: optical contact angle measuring device (OCA 50, DataPhysics Instruments GmbH), composed of an optical set up lenses, lamp, dosing system, video camera, movable stage X,Y and Z direction and tilt table (0-95°, inclination) Tested liquid: water

Table tilt angle: between 0 and 90°

Drop size: 20 pl

Syringe external diameter: 0.52 mm

Number of drops on the surface: 3

Samples of the surface-modified materials were positioned and fixed on the stage of the OCA measuring device under the dosing system. Water was loaded into the dosing system and drops of 20 pl were dispensed on the sample surface. The first drops on the surface were used to adjust the image that was used to analyze the contact angles and tilt angles of the surfaces when the drop slides down from the surface. The drop needs high definition and the base diameter displayed on the computer screen is suggested to be less than the % of the field view. Drops were evaluated and recorded while the table, which was in the horizontal position, started to tilt until the water drop slided down from the surface. The calculation method used for this application was the polynomial fitting because the drop was not symmetric. Advancing (front of the drop when tilted) and receding (back of the drop when tilted) water contact angles were measured when the drop started to slide. The hysteresis was calculated by the subtraction of the advancing angle from the receding angle.

3.7. Surface tension

Equipment: optical contact angle measuring device (OCA 50, DataPhysics Instruments GmbH), composed of an optical set up lenses, lamp, dosing system, video camera, movable stage X,Y and Z direction and tilt table (0-95°, inclination)

Tested liquid: water, silicon oil 10 (IL1), silicon oil 20 (IL2), silicon oil 50 (IL3), silicon oil 100 (IL4) Drops were continuously dosed and 3 drops were measured

Syringe external diameter: 1 .62 mm

The OCA measuring device was used in the pedant drop set up. The camera was positioned in the way that the drop can be measured when the drop is suspended on air (left hand side). Continuous dosing was required and a video was recorded. The calculation method used was Young- Laplace.

3.8. Gloss measurement

The surface reflectance of the surface-modified material samples was characterized by gloss measurement using a Surfoptic Imaging Reflectometer (SIRS 75 & SIRS 75/M, Dayta Systems Ltd.). The light reflected and scattered forwards into a specified angular range was collected and measured relative to a defined standard surface of specified refractive index. G20 is a gloss with a nominal 20° acceptance angle. These values were derived using the angular distribution of scattered light as measured on the imaging detector (cf. Elton, Reflectometry Technical Paper No. 2, April 2004 Revised May 2007, Surfoptic)

The evaluation of the sample was done on a surface area of 40 X 40 mm with a mapping mesh of 25 knots, the knots were located 10 mm away from the each other in x and y direction. The values were recorded and the arithmetic average was calculated.

The liquid infusion on these samples was performed by spray coating. 3.9. Antimicrobial evaluation

The antimicrobial analysis on surface-modified material samples comprising a contained liquid layer including a biocide was evaluated in accordance with ISO 22196/JIS Z 2801 :2010.

The liquid infusion on this samples was performed by spray coating.

3.10. Liquid absorption on surface coated paper (viscosity vs. time evaluation on porous coatings)

The accessible pore volume of paper comprising a porous coating layer was measured by absorbing liquid. The coated sample was weighed initially, then hung, dipping into a dish of liquid, in a wicking configuration with its planar surface held vertically. The weight loss from the dish was continually recorded in a draught-free environment. When the recorded weight was constant, indicative of saturation, the sample was weighed again. Dividing the weight difference by the density of the liquid gives the volume intruded into the sample, and hence the volume per gram of sample can be calculated. ( Gane, P. A. C., Schoelkopf, J., Spielmann, D. C., Matthews, G. P., Ridgway, C. J. (2000): Fluid Transport into Porous Coating Structures: Some Novel Findings, Tappi Journal, 83 (5), 77. TAPPI Press (1998): "1998-1999 Tappi Test Methods", Tappi Press, Atlanta). The sample size evaluated had dimensions of 1 .5 x 2 cm and a coating thickness of 27 pm.

4. Examples

4.1. Example 1 - Preparation of substrates with porous coating layers

Water was poured into a vessel, the dispersant was added, and it was mixed until the dispersant was dissolved. Subsequently, the stirred speed was increased and the mineral particles were added stepwise. Extra water was added into the solution in case the dispersion was too thick. The mixture was stirred until total integration at high speed.

Afterwards, the obtained mixture was mixed manually with the binder.

When swellable binder was employed (binder B1), the solids content of the obtained mixture was decreased to 10 wt.-% and the pH was increased to 9 with NaOH (10 wt.-%).

The compositions of the prepared coating compositions are compiled in Table 3 below.

The coating compositions were applied to the substrate with a target coating weight of 10 g/m ² or 20 g/m ² using the Erichsen table coater and dried in the oven at 85 °C for approximately two minutes.

Table 3: Composition of substrates with porous coating layers.

The porosity of the formed porous coating layers was examined as described in section 3.1 . above and the surface topography of selected samples was analysed as described in section 3.5. above. The results of representative samples are compiled in Tables 4 and 5 below. SEM micrographs of coated substrate sample 9 are shown in Figs. 1 , 2 and 3, SEM micrographs of coated substrate sample 5 are shown in Figs. 4 and 5, and SEM micrographs of coated substrate sample 8 are shown in Figs. 6 and 7.

Table 4: Porosity of the porous coating layers produced according to Example 1 .

Table 5: Surface topography of porous coating layers produced according to Example 1 .

4.2. Example 2 - Infusing porous coating layers with infusing liquid composition

Dip coating

The coated substrates obtained in Example 1 were mounted on microscope slides and dip coated with the infusing liquid composition. Double-sided tape was used to stick the coated substrate on the microscope slide. Uncovered slide area was cleaned with ethanol and the sample was dedusted with compressed air. Rectangular (capacity 4 microscope slides) or round (capacity 1 microscope slide) shaped disposable petri dishes were used with approximate 4 ml of the infusing liquid composition. The microscope slide with the coating downward-facing was immersed into the infused liquid for 5 minutes.

Once the time of immersion was finished, the excess of liquid was removed with a tissue and ethyl acetate followed by centrifugation

• 1000 rpm for 1 min for low viscous infusing liquid composition (IL1 , IL6)

• 1000 rpm >1 min for high viscous infusing liquid composition (IL4, IL5, IL7).

The remaining liquid at the edge was removed carefully with a tissue. Samples were weighted before and after the dip coating to obtain the amount of contained liquid layer within and on the porous coating layer.

Samples 1 to 26 compiled in Table 7 below were prepared by dip coating. The employed infusing liquid composition and, the amount of contained liquid layer are indicated in Table 7.

Spray coatings

Once the amount of liquid was known, from the dip coating technique, the total weight was loaded on larger areas. A precision spray device was used to apply the infusing liquids onto the coated substrates. Samples 27 and 28 were prepared by spray coating, wherein the employed infusing liquid composition and the amount of contained liquid layer are indicated in Table 7 below. Results

Characterization of infusion liquids

The surface tension of the tested infusion liquids was examined by measuring the surface tension as described in section 3.7. above. Table 6: Surface tension of tested infusion liquids.

Surface characteristics of surface-modified materials

The surface characteristics of the prepared surface-modified materials were examined by measuring the optical contact angle of water drops as described in section 3.6. above. The results are compiled in Table 7 below. Antimicrobial activity

The antimicrobial activity of the surface-modified material samples 27 and 28 was evaluated in accordance with the protocol given in ISO 22196/JIS Z 2801 :2010. The results are compiled in Table 8 below. Sample 28 comprising a contained layer of IL7 in combination with 250 ppm biocide showed a very good antimicrobial activity (test no. 5 and 6). This confirms that a biocide can be locked within the porous coating layer by infusing the coating layer with an infusing liquid comprising a biocide.

able 7: Composition and surface characteristics of surface-modified materials.

Table 8: Antimicrobial activity of surface-modified samples 27 and 28.

Gloss measurement

Coated substrate 9 was infused with different amounts of the infusing liquid composition IL1 by spray coating, wherein a contained liquid layer amount of about 18 g/m ² was considered to represent 100% of porous coating layer loading. The results of the gloss measurements are shown Fig. 8.

SEM micrographs

SEM micrographs of coated substrate 9 without a contained liquid layer (Fig. 9) and comprising a contained liquid layer of IL1 in an amount of 0.012 g/26 mm x 26 mm coating area is shown in Fig. 10.

Saturation time

Coated substrate 9 was infused with infusing liquid compositions having different viscosities (IL1 , IL2, IL3, IL4) to evaluate the effect of viscosity versus the filling time of the porous coating. The infusing liquid was infused into the porous coating layer as described in section 3.10 above. The results are shown in Fig. 11 .

4.3. Example 3 - Preparation of substrates with porous coating layers

Four emulsion paints were prepared by mixing in a first step all components listed in Table 9 below, except for the minerals and titanium dioxide. Every component, besides the minerals and titanium dioxide, was mixed in the order given in Table 9 under low sheer, i.e. only up to 1000 rpm, to avoid foaming. Only after the addition of Bermocoll Prime 3500 there was a break of 2 - 3 minutes to ensure that it was well dispersed before adding the sodium hydroxide.

Subsequently, the mineral and titanium dioxide, if present, were added and carefully mixed with a spatula until all particles have been wetted. Finally, the composition was mixed in a speed mixer 2 times for 2 minutes each at 3000 rpm. The compositions of the prepared emulsion paints are compiled in Table 9 below.

The prepared paints were applied as coating compositions to the substrate S1 with a target coating weight of 100 to 140 g/m ² using the Erichsen table coater, and were dried at room temperature, 23°C at 50% humidity, for at least 24 hours. Table 9: Emulsion paint compositions (amounts are given in wt.-% based on the total weight of the composition).

The porosity of the formed porous coating layers was examined as described in section 3.1 . above. The results are compiled in Table 10 below. Table 10: Porosity of the porous coating layers produced according to Example 3.

4.4. Example 4 - Infusing porous coating layers with infusing liquid composition

The coated substrates obtained in Example 3 were mounted on microscope slides and dip coated with the infusing liquid composition. Double-sided tape was used to stick the coated substrate on the microscope slide. Uncovered slide area was cleaned with ethanol and the sample was dedusted with compressed air. Rectangular (capacity 4 microscope slides) or round (capacity 1 microscope slide) shaped disposable petri dishes were used with approximate 4 ml of the infusing liquid composition. The microscope slide with the coating downward-facing was immersed into the infused liquid for 5 minutes. Once the time of immersion was finished, the excess of liquid was removed with a tissue and ethyl acetate followed by centrifugation at 1000 rpm for 1 min. The remaining liquid at the edge was removed carefully with a tissue. Samples were weighted before and after the dip coating to obtain the amount of contained liquid layer within and on the porous coating layer. The employed infusing liquid composition and, the amount of contained liquid layer are indicated in Table 11 below. Table 11 : Composition and surface characteristics of surface-modified materials.

4.5. Conclusion

The examples show that slippery liquid infused porous surfaces (SLIPS) could be prepared by using a coating of mineral particles as basis for the infusion of an infusing liquid composition. It was possible to tailor the surface topography of the porous coating layer by the morphology of the mineral particles and the composition of the coating formulation.

Furthermore, it was shown that the surface of the surface-modified material can be easily equipped with additional functionalities such as antimicrobial properties.