Particle materials

Abstract

1. A particulate material Z consisting of 15% to 50% by weight of particles X made of a water-insoluble support material T provided with elemental silver and elemental ruthenium, and 50% to 85% by weight of a solid Y at least partially disposed on the particles X, wherein the solid Y is selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium (IV) oxyhydrate, titanium dioxide, titanium (IV) oxyhydrate, and combinations thereof.

Description

[Technical Field]

[0001] The present invention relates to a particulate material (powder) comprised of a water-insoluble support material provided with elemental silver and elemental ruthenium, the solids being at least partially disposed on the particles. The solids are selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium(IV) oxyhydrate, titanium dioxide, titanium(IV) oxyhydrate, and combinations thereof. The present invention also relates to a method for preparing the particulate material and uses thereof. Summary of the Invention [Problem to be solved by the invention]

[0002] WO 2021 / 084140(A2) discloses a particulate carrier material that can be used as an additive for the antimicrobial treatment of many different materials and can comprise elemental silver and elemental ruthenium. This material has a corresponding low color value L * (e.g., in the range of 35-45). Dark colors can limit the usefulness of antimicrobial treatments for light materials and objects.

[0003] U.S. Patent No. 5,985,466 discloses a powder having a metal oxide film on its surface, which has an increased refractive index and therefore high reflectivity and bright color. The powder includes substrate particles having a multilayer film on its surface, which includes at least one metal oxide layer. A method for preparing the powder includes dispersing the substrate particles in a solution of a metal alkoxide, hydrolyzing the metal alkoxide to obtain a metal oxide, and depositing the metal oxide film on the surface of the substrate particles. These steps are performed two or more times to form a multilayer metal oxide film, and at least the last step is a heat treatment. The multilayer metal oxide film is thereby adjusted to have an appropriate combination of constituent materials and an appropriate film thickness to change the interference color of the multilayer film and impart a bright color to the powder.

[0004] The lightness L referred to in this specification and claims * is CIEL * a * b * L in color space (DIN EN ISO / CIE 11664-4:2020-03) * and is determined spectrophotometrically in a measurement geometry of d / 8°. Spectrophotometric measurements of powder materials can be carried out on material samples filled into colorless glass containers with a filling height of 1 cm through the flat glass bottom of the glass container placed on the measuring head of the spectrophotometer used.

[0005] The present invention, described below, solves the aforementioned color or brightness problems by providing a particulate material that can be used as an antimicrobial additive and has a relatively light color, particularly a color lighter than the material disclosed in WO 2021 / 084140(A2). Due to its light color, the particulate material according to the present invention is also suitable for antimicrobial design of relatively light-colored materials and objects.

[0006] The present invention relates to a particulate material Z comprising 15% to 50% by weight of particles X of a water-insoluble support material T provided with elemental silver and elemental ruthenium, and 50% to 85% by weight of a solid Y at least partially disposed on the particles X, wherein the solid Y is selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium(IV) oxyhydrate, titanium dioxide, titanium(IV) oxyhydrate, and combinations thereof. The weight percentages of components X and Y add up to 100% by weight. Selection of the X:Y weight ratio within the range according to the present invention can be used to determine the color or lightness L of the particulate material Z according to the present invention. * The particulate material Z according to the invention has a lightness L in the range of, for example, 50 to 85. * The proportion of silver and ruthenium in the particulate material Z may be in the range of, for example, 0.015% to 25% by weight.

[0007] The solid Y constitutes 50% to 85% by weight of the particulate material Z according to the present invention and is at least partially disposed on the particles X of the particulate material Z according to the present invention, i.e., a certain proportion of 50% to 85% by weight of the solid Y can be present "free" as free solid Y in addition to the particles X on which the solid Y is disposed and, optionally, the particles X on which the solid Y is not disposed. Thus, when viewed using a scanning electron microscope, the particulate material Z according to the present invention substantially comprises or consists of a mixture of the particles X on which the solid Y is disposed and the free solid Y. The proportion of the free solid Y in the total amount of the solid Y can be, for example, in the range of 10% to less than 100% by weight, for example, in the range of 10% to 90% by weight.

[0008] Solid Y is selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium(IV) oxyhydrate, titanium dioxide, titanium(IV) oxyhydrate, and combinations thereof. Titanium dioxide, titanium(IV) oxyhydrate, or combinations thereof, particularly titanium dioxide, is preferred. Solid Y has a particulate form, i.e., both free solid Y and solid Y disposed on particles X are formed as particles. In other words, solid Y is not layered; it does not form any layer or coating in the sense of a closed layer. Therefore, in other words, particles X do not have a single-layer or multi-layer coating, in particular, a single-layer or multi-layer coating, one or more layers of which contain or consist of solid Y.

[0009] Solid Y placed on particle X adheres to particle X and cannot be easily separated from particle X, for example by washing or shaking. The adhesion of solid Y onto particle X is essentially physical in nature, although the possible formation of chemical bonds cannot be excluded.

[0010] Particles X consist of particles of a water-insoluble support material T comprising elemental silver and elemental ruthenium. Comprising elemental silver and elemental ruthenium means that, depending on the type of support material T, silver and ruthenium can be present on the inner surface (in pores and / or cavities) and / or outer surface of the support material particles, thereby forming, for example, a continuous or discontinuous layer and / or small silver or ruthenium particles. Silver and ruthenium adhere to the surface of the support material particles; the adhesion is essentially physical in nature, although the possible formation of chemical bonds cannot be excluded. Silver and ruthenium are not alloyed but rather randomly distributed. It will be clear to those skilled in the art that the silver and ruthenium on the surface may also contain other silver species than elemental metallic silver and other ruthenium species than elemental metallic ruthenium, such as the corresponding oxides and / or halides and / or sulfides. The particles X of the water-insoluble support material T provided with elemental silver and elemental ruthenium may in particular have a silver+ruthenium weight proportion ranging from 0.1% to 50% by weight, with a silver:ruthenium weight ratio ranging from 1 part by weight to 2,000 parts by weight of silver:1 part by weight of ruthenium.

[0011] The fact that the water-insoluble carrier material T of particles X exists in an agglomerated solid state will be apparent to those skilled in the art.

[0012] The support material particles T can have a wide variety of particle shapes. For example, they can be irregularly shaped or they can have a defined shape. They can be, for example, spherical, ellipsoidal, platelet-like, or rod-like. The support material particles T can be porous and / or have cavities, or none of these. They can have a smooth, rough, or structured outer surface. The support material particles can have an average particle size (d50) in the range of, for example, 0.4 μm to 100 μm. The absolute particle size of the support material particles T is generally less than 0.1 μm and generally does not exceed 1,000 μm.

[0013] The term "average particle size" as used herein refers to the average particle size (d50) that can be determined by laser diffraction. Laser diffraction measurements can be performed using a corresponding particle size measuring device, such as the Mastersizer 3000 from Malvern Instruments.

[0014] The water-insoluble particulate support material T has a more or less large water absorption capacity between particles and, optionally, within the particles, for example, within pores and / or depressions on the particle surface. The water-insoluble particulate support material T may be swellable with water or even capable of forming a hydrogel. It is not attacked, dissolved, or its properties as support material T are impaired by water. The actual water-insoluble support material T itself is preferably a non-water-repellent material. It is preferably hydrophilic, but in either case, as described, is water-insoluble. The actual support material T may be a material selected from inorganic or organic substances or materials, in each case in particulate form, for example, a powder. For the avoidance of doubt, the support material T is a silver-free, ruthenium-free substance or a silver-free, ruthenium-free material. The support material T is preferably neither magnetic nor magnetizable, and is not carbonyl iron. Examples of type T support materials include glass; nitrides such as aluminum nitride, titanium nitride, and silicon nitride; high-melting-point oxides such as aluminum oxide, titanium dioxide, and silicon dioxide, such as silica or quartz; silicates such as sodium aluminum silicate, zirconium silicate, and zeolites; plastic materials such as (meth)acrylic homo- and copolymers and polyamides; modified or unmodified naturally occurring polymers such as polysaccharides and polysaccharide derivatives, especially cellulose and cellulose derivatives; carbon substrates, especially porous carbon substrates; and wood. The water-insoluble support material T of the particles X may be the same as or different from the solid Y. Silicon dioxide, titanium dioxide, and cellulose are preferred support materials T, especially in the form of linear cellulose fibers having fiber lengths in the range of 10 μm to 1,000 μm.

[0015] Particles X made of a water-insoluble carrier material T provided with elemental silver and elemental ruthenium are free-flowing (non-agglomerating) powders. The free-flowing properties of the free-flowing powders can be determined by the rotational powder analysis method described below.

[0016] The particles X of a water-insoluble support material T provided with elemental silver and elemental ruthenium may be, for example, a material of the type disclosed in WO 2021 / 084140(A2). WO 2021 / 084140(A2) also discloses a method for preparing a particulate support material of type X provided with elemental silver and elemental ruthenium. For the sake of brevity, explicit reference is made in this respect to the disclosure of WO 2021 / 084140(A2), page 2, line 6 to page 13, line 17, both with regard to this material and this preparation method.

[0017] The particulate material Z according to the invention can be produced by contacting particles X of a water-insoluble support material T provided with elemental silver and elemental ruthenium with at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium and / or titanium in the presence of water in an amount at least sufficient for complete hydrolysis of the at least one C1-C4 alkoxide. In this respect, the invention also relates to such a preparation method.

[0018] As mentioned above, particulate material Z according to the present invention can be prepared by complete hydrolysis of at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or preferably titanium in the presence of particles X; i.e., the method for preparing particulate material Z according to the present invention comprises complete hydrolysis of at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or preferably titanium in the presence of particles X. In other words, the method for preparing particulate material Z according to the present invention comprises contacting particles X with at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or preferably titanium in the presence of water in an amount at least sufficient for complete hydrolysis of the at least one C1-C4 alkoxide. The C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or preferably titanium is preferably aluminum trialkoxide Al(OC n H 2n+1 )3, magnesium dialkoxide Mg(OC n H 2n+1 )2, calcium dialkoxide Ca(OC n H 2n+1 )2, silicon tetraalkoxide Si(OC n H 2n+1 ) 4, zinc dialkoxide Zn(OC n H 2n+1 )2, zirconium tetraalkoxide Zr(OC n H 2n+1 ) 4, and / or preferably titanium tetraalkoxide Ti(OC n H 2n+1)4, where n=1, 2, 3, or 4 in each case, preferably 3. In the preferred case of n=3, it is particularly preferred to work with isopropoxides, in particular titanium tetraisopropoxide Ti[OCH(CH3)2]4, also called TTIP. TTIP is preferably used alone. Since the hydrolysis proceeds quantitatively, it is easy for those skilled in the art in preparing the particulate material Z according to the invention to make quantitative selections according to stoichiometric considerations regarding at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or preferably titanium, as well as the particles X. For this complete hydrolysis, those skilled in the art will select at least 1 mole of water per mole of C1-C4 alkoxide of magnesium, calcium, or zinc to be hydrolyzed, at least 1.5 moles of water per mole of C1-C4 alkoxide of aluminum to be hydrolyzed, and at least 2 moles of water per mole of C1-C4 alkoxide of silicon, zirconium, or titanium. As explained below, water can be provided as atmospheric moisture, as the moisture content of particles X, and / or in liquid form in an amount of water that is at least sufficient for complete hydrolysis of at least one C1-C4 alkoxide, but generally a superstoichiometric quantitative proportion of water relative to the hydrolysis reaction.

[0019] For the sake of brevity, the expression "C1-C4 alkoxides of aluminum, magnesium, calcium, silicon, zinc, zirconium and / or preferably titanium" will also be referred to below simply as "alkoxides".

[0020] According to the present invention, particles X can be contacted with at least one alkoxide in the presence of water in an amount sufficient for at least complete hydrolysis. The alkoxide is hydrolyzed to form the corresponding C1-C4 alcohol and a corresponding solid Y selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium(IV) oxyhydrate, titanium dioxide, titanium(IV) oxyhydrate, and combinations thereof. This allows solid Y to adhere proportionally to particles X. As a result, particulate material Z according to the present invention is formed as the process product. After hydrolysis, the resulting product can be subjected to one or more further process steps, if necessary. Examples of such process steps include, inter alia, solid-liquid separation, washing, drying, and grinding.

[0021] The method according to the present invention, particularly the hydrolysis, can be carried out at a temperature ranging from, for example, 0°C to 80°C, preferably from 20°C to 40°C.

[0022] In a first embodiment of the method according to the invention, particles X can be directly contacted with at least one alkoxide. In this first embodiment of the method according to the invention, particles X can be dry or anhydrous, or can have a water content, for example, in the form of residual moisture, for example, in the range of more than 0% to 40% by weight. At least one alkoxide can be used undiluted or diluted with a water-dilutable organic solvent, for example, as a solution in a water-dilutable organic solvent. Such a preparation or solution can have a weight proportion of at least one alkoxide in the range of, for example, 20% to less than 100% by weight, preferably 50% to 70% by weight. Examples of suitable water-dilutable organic solvents are, in particular, C1-C3 alcohols, in particular ethanol. Hereinafter, "optionally diluted at least one alkoxide" will also be referred to, for the sake of brevity, by the shortened form "at least one alkoxide."

[0023] In a first embodiment of the method according to the invention, water itself is not added at any point, and hydrolysis can occur under the influence of atmospheric moisture and any moisture present in the particles X. The atmospheric moisture can of course be the general atmospheric moisture or can be artificially set to a desired value, and the ingress of air can, if desired, be forced by deliberate air supply.

[0024] In a first embodiment of the method according to the present invention, particles X, optionally containing moisture, and at least one alkoxide, optionally diluted, are brought into contact with each other to form a pulp-like, paste-like, or dough-like mass, a suspension, or preferably a free-flowing impregnated particulate material. The at least one alkoxide, optionally diluted, constitutes the impregnating agent. Particles X can be added to at least one alkoxide, or vice versa. The at least one alkoxide is preferably added to previously provided particles X. After the addition is complete, the reaction mixture can be conveniently allowed to continue for an additional time, for example, in the range of 0.5 to 3 hours, before further process steps are carried out. In this way, completeness of the hydrolysis reaction and homogenization of the reaction mixture can be ensured. Generally, mixing is carried out during and also after the addition. Examples of suitable mixing methods depend on the nature of the materials being mixed and can include, for example, shaking, stirring, and / or kneading. In the preferred case of a mixed material in the form of a free-flowing, impregnated particulate material, powder mixing methods known to those skilled in the art, operating continuously or discontinuously, are suitable, such as mixing in a drum mixer, a tumble mixer, a pressure filter operated without pressure and having an agitator, or a vacuum mixer dryer operated under vacuum-free conditions and without heating. The expression "free-flowing, impregnated particulate material" as used herein refers to a material in the form of impregnated grains or flakes, each of which may contain one or more particles X. The free-flowing, impregnated particulate material is not a liquid, liquid dispersion, or suspension; rather, it is a free-flowing material in the form of a free-flowing powder. Its free flowability, or generally the free flowability of a free-flowing powder, can be determined by rotational powder analysis. For this purpose, a cylindrical measuring drum can be filled with a predetermined volume of the free-flowing, impregnated particulate material. The measuring drum has a predetermined diameter and a predetermined depth. The measuring drum rotates around a horizontally oriented cylindrical axis at a predetermined, constant speed. One of the two end faces of the cylinder, which together enclose the free-flowing impregnated particulate material packed in a cylindrical measuring drum, is transparent. Before the start of the measurement, the measuring drum is rotated for 60 seconds.During the actual measurement, images of the free-flowing, impregnated particulate material are then captured along the rotation axis of the measuring drum using a camera with a high frame rate, e.g., 5 to 15 images per second. The camera parameters can be selected to obtain the highest possible contrast at the material-air interface. During the rotation of the measuring drum, the free-flowing, impregnated particulate material is carried to a certain height against gravity and then falls to the bottom of the drum. The falls occur in a discontinuous manner, also known as avalanches. The measurement ends when a statistically relevant number of avalanches, e.g., 200 to 400 avalanche slides, have been recorded. The camera images of the free-flowing, impregnated particulate material are then evaluated by digital image analysis. During rotational powder analysis, the so-called avalanche angle as well as the time between two avalanches ("avalanche time") can be determined as parameters characteristic of free flow. The avalanche angle is the angle of the material surface at which an avalanche occurs and therefore represents a measure of the height of the free-flowing particulate material pile before it collapses like an avalanche. The time interval between two avalanches corresponds to the time elapsed between the occurrence of the two avalanches. A suitable tool for performing this rotational powder analysis and determining the avalanche angle and the time interval between two avalanches is the Revolution Powder Analyzer manufactured by PS Prozesstechnik GmbH (Neuhausenstrasse 36, CH-4057 Basel). It is recommended to follow the operating instructions and recommendations included with the instrument. Measurements are typically performed at room temperature or 20°C. In this case, the free-flowing, impregnated particulate material can have an avalanche angle ranging from 40° to 90°, for example, as determined based on a 100 mL test volume of material using the instrument at 0.5 revolutions per minute and a cylinder with a 35 mm internal depth and a 100 mm internal diameter. The time between two avalanches can range from 2 seconds to 5 seconds, for example, and can characterize the free-flowing nature of the free-flowing, impregnated particulate material.

[0025] In a first embodiment of the method according to the invention, the particles X can be contacted with at least one alkoxide in multiple steps carried out in the same way, i.e. the at least one alkoxide can be contacted with the total amount of particles X in multiple portions, a drying process being carried out in each case between the individual steps.

[0026] The second embodiment of the method according to the present invention differs from the first embodiment in that the particles constituting the free-flowing powder, whether anhydrous or with a moisture content, are first uniformly moistened with water or further moistened with water to obtain particles X'. Thus, particles X' differ from particles X due to their moisture content or higher moisture content. The additional steps in the second embodiment of the method according to the present invention correspond to those in the first embodiment of the method according to the present invention. During moistening, the desired moisture content of particles X' can be set, for example, in the range of 1% to 50% by weight. Thus, particles X can be added to water, or vice versa, to form a mixture in each case. Generally, mixing is performed during and after the addition. Examples of suitable mixing processes are based on the nature of the materials to be mixed and can therefore include, for example, shaking, stirring, and / or kneading. In the preferred case of a mixed material in the form of a water-moistened, free-flowing particulate material, powder mixing methods operating continuously or discontinuously known to those skilled in the art, such as those described above for the first embodiment of the method according to the present invention, are suitable. Preferably, water is added to the particles X, which may optionally contain moisture, beforehand. After the addition is complete, the wet mixed material may be further conveniently allowed to stand for a period of time ranging, for example, up to 1 hour, before being contacted with at least one alkoxide. In this way, homogenization or uniform wetting of the mixed material can be ensured, in other words, a uniform distribution of water within the resulting particles X' can be ensured before they are subsequently contacted with at least one alkoxide. Generally, mixing is carried out during and also after the addition.

[0027] The free flowability of particle X' can be determined by rotational powder analysis as described above, where particle X' can have an avalanche angle ranging from, for example, 40 degrees to 90 degrees, and the time between two avalanches can range from, for example, 2 seconds to 5 seconds, as determined based on a 100 mL test volume using a Revolution Powder Analyzer at 0.5 revolutions per minute and a cylinder having an internal depth of 35 mm and an internal diameter of 100 mm.

[0028] In a second embodiment of the method according to the present invention, particles X' and at least one optionally diluted alkoxide are brought into contact with each other to form a pulp-like, paste-like, or dough-like mass, a suspension, or preferably a free-flowing, impregnated particulate material. The at least one alkoxide constitutes the impregnating agent. Particles X' can be added to at least one alkoxide, or vice versa. The at least one alkoxide is preferably added to previously provided particles X. After the addition is complete, the reaction mixture may be allowed to further elapse, for example, between 0.5 and 3 hours, before further process steps are carried out. In this way, completeness of the hydrolysis reaction and homogenization of the reaction mixture can be ensured. Generally, mixing is carried out during and also after the addition. Examples of suitable mixing processes depend on the nature of the materials to be mixed and can therefore include, for example, shaking, stirring, and / or kneading. In the case of a mixed material in the form of a free-flowing particulate material, continuous or discontinuous powder mixing methods known to those skilled in the art, such as the procedures already described for the first embodiment of the method according to the present invention, are suitable.

[0029] In a third embodiment of the method according to the present invention, particles X, optionally containing moisture, are first suspended in an aqueous medium of water and a water-dilutable organic solvent. The suspension may, for example, consist of 50% to 95% by weight of the aqueous medium and 5% to 50% by weight of particles X, the weight percentages adding up to 100% by weight. The aqueous medium may, for example, consist of more than 0% to 95% by weight of water and 5% to less than 100% by weight of a water-dilutable organic solvent, the weight percentages adding up to 100% by weight. Examples of suitable water-dilutable organic solvents are, in particular, C1-C3 alcohols, in particular ethanol.

[0030] The suspension and at least one optionally diluted alkoxide are then brought into contact with each other. The suspension can be added to the at least one optionally diluted alkoxide, or vice versa. The at least one optionally diluted alkoxide is preferably added to the previously provided suspension. The addition can be carried out continuously or discontinuously. After the addition is complete, the reaction mixture can be conveniently allowed to continue for a further period of time, for example, in the range of 0.5 to 3 hours, before further process steps are carried out. In this way, the completeness of the hydrolysis reaction and the homogenization of the reaction mixture can be ensured. Generally, mixing is carried out during and also after the addition, for example by shaking and / or stirring.

[0031] The first and third embodiments of the method according to the invention are preferred embodiments.

[0032] As already mentioned, after hydrolysis, the obtained process product may be subjected to one or more further process steps, if necessary. Examples of such process steps include, in particular, solid-liquid separation, washing, drying, and grinding. Such further process steps are carried out in the second and third embodiments, but generally also in the first embodiment. Therefore, in the first embodiment of the method according to the present invention, it is generally advantageous if successive drying and grinding are carried out. In the second and third embodiments, washing and solid-liquid separation are conveniently carried out alternately, and then drying and grinding are carried out sequentially.

[0033] The solid-liquid separation can be carried out using methods known to those skilled in the art, such as decantation, squeezing, filtration, suction filtration, centrifugation, or similar procedures, to separate at least a large portion of the liquid (C1-C4 alcohol formed by hydrolysis, water, water-dilutable solvent) from the particulate material Z formed or washed during the hydrolysis, resulting in a wet particulate material Z that still contains the liquid.

[0034] Washing is expediently carried out with water, a process which makes it possible to remove water-soluble components, such as C1-C4 alcohols and / or water-dilutable organic solvents formed during hydrolysis.

[0035] Drying may be carried out under ambient conditions in air without special measures, or may be assisted by the application of reduced pressure and / or heat. Suitable drying temperatures are, for example, in the range of 50°C to 150°C. After drying, no further heat treatment, such as tempering at a temperature higher than the drying temperature, is necessary. Such heat treatment is generally and preferably not carried out.

[0036] Grinding can be carried out, for example, in a mortar or by grinding (eg, using a rotor beater mill).

[0037] The method according to the invention is scalable in production scale and particulate material Z according to the invention can be efficiently produced in batch sizes of, for example, amounts of up to 5 tonnes.

[0038] The particulate material Z according to the invention has antibacterial activity comparable to that of materials known as antibacterial additives from WO 2021 / 084140(A2). The invention therefore also relates to the use of the particulate material Z according to the invention as an additive for the antibacterial treatment of metal surfaces, coatings, plasters, molding bases, plastic films, plastic parts, or plastic fibers, synthetic resin products, ion exchange resins, silicone products, cellulosic products, foams, textiles, cosmetics, hygiene products, and many other articles. The cellulosic products can be selected, for example, from the group consisting of paper products, paperboard, wood fiber products, and cellulose acetate. The plastic materials can be selected, for example, from the group consisting of ABS plastic materials, PVC (polyvinyl chloride), polylactic acid, PU (polyurethane), poly(meth)acrylate, PC (polycarbonate), polysiloxane, phenol-formaldehyde resin, melamine-formaldehyde resin, polyester, polyamide, polyether, polyolefin, polystyrene, their hybrid polymers, and mixtures thereof. In principle, the color of the material or object to be made antibacterial is arbitrary in this case. However, in particular, the material or object to be made antibacterial is preferably one having a light color, for example, a color value L in the range of 50 to 90. * The particulate material Z according to the present invention may have a chromatic or achromatic color having a color or shade that is adapted to the material or object to be made antibacterial. It is also possible to use the particulate material Z according to the present invention in combination with a colorless or dark antibacterial active additive, for example, to use the particulate material Z according to the present invention in combination with an antibacterial active particulate carrier material comprising elemental silver and elemental ruthenium (for example, as known from WO 2021 / 084140(A2)). [Example]

[0039] Reference Example 1 (Preparation of cellulose powder with elemental silver and elemental ruthenium according to embodiment 3 of WO 2021 / 084140(A2)): 75.6 g (445 mmol) of silver nitrate solid and 13.94 g of ruthenium nitrosylnitrate solution (ruthenium content 19.0 wt. %, 26.2 mmol of Ru) were dissolved in 416.8 g of deionized water. The resulting aqueous precursor solution was uniformly mixed with 211.2 g of cellulose powder (Vitacel® L-600, Rettenmaier und Söhne GmbH & Co. KG) to form an orange, free-flowing granular material. 705 mL of an aqueous hydrazine solution with a pH of 13.9 [4.19 g (131 mmol) of hydrazine and 81.81 g of 32 wt. % sodium hydroxide solution (654.51 mmol of NaOH), the remainder water] was metered in at room temperature with stirring at a metered addition rate of 30 mL / min. A black, homogeneous pulp was formed, which became increasingly easier to stir over time. After the metering was complete, stirring was continued for 30 minutes until nitrogen evolution was no longer observed. The material was then filtered off by suction, washed with a total of 1,000 mL of water, and dried in a drying cabinet at 105°C / 300 mbar to a residual water content of 15% by weight. The silver content of the final product was 18.9% by weight and the ruthenium content was 1.0% by weight (relative to a residual water content of 0% by weight) determined by ICP-OES.

[0040] The final product was ground in an agate mortar, and the powder thus obtained appeared black to the human eye. After filling a colorless snap-cap vial to a fill height of 1 cm, a spectrophotometer (ColorLite sph900 spectrometer) was used to measure the concentration of 44 L at a measurement geometry of d / 8° through the glass bottom of the snap-cap vial, which was placed on the measurement head of the spectrophotometer. * value was determined.

[0041] Inventive Example 2 (Preparation of Z-type particulate material): 50 g of the black powder from Reference Example 1 containing 15 wt. % residual moisture was initially placed in a 6 L flask in contact with the ambient atmosphere and suspended in a mixture of 970 mL of ethanol and 35 mL of deionized water. 533.85 g of TTIP was dissolved in 400 mL of ethanol and added to the stirred suspension at a rate of 5 mL / min, followed by stirring for an additional 2 hours. The resulting mixture was then filtered, and the resulting light gray solid was washed with 7 L of deionized water, dried at 105 °C (300 mbar) for 24 hours, and then ground using an agate mortar. The silver content of the final product was 4.3 wt. % and the ruthenium content was 0.2 wt. % (relative to 0 wt. % residual moisture) were determined by ICP-OES. The powder thus obtained appeared light gray to the human eye. After filling colorless snap-cap vials to a fill height of 1 cm, a spectrophotometer (ColorLite sph900 spectrometer) was used to measure 65 L with a measurement geometry of d / 8° through the glass bottom of the snap-cap vial placed on the measurement head of the spectrophotometer. * value was determined.

[0042] Inventive Example 3 (Preparation of Z-type particulate material): 50 g of the black powder from Reference Example 1 containing 15 wt. % residual moisture was dried at 105 °C / 300 mbar. The resulting dried powder was first transferred to a 6 L flask in contact with the ambient atmosphere and further processed as in Example 2. The silver content of the final product was determined to be 4.3 wt. % and the ruthenium content of 0.2 wt. % (relative to 0 wt. % residual moisture) by ICP-OES. The powder thus obtained appeared light gray to the human eye. After filling a colorless snap-cap vial to a fill height of 1 cm, a spectrophotometer (ColorLite sph900 spectrometer) was used to measure the 65 L peak with a d / 8° measurement geometry through the glass bottom of the snap-cap vial, which was placed on the measurement head of the spectrophotometer. * value was determined.

[0043] Inventive Example 4 (Preparation of Z-type particulate material): 10 g of the black powder from Reference Example 1 containing 15 wt. % residual moisture was mixed dropwise with 6.84 g of TTIP while stirring. After stirring the mixture for 10 minutes with air, it was transferred to a ceramic bowl and dried at 105 °C / 300 mbar. The resulting powder was ground using an agate mortar. This series of steps was repeated 9 times, i.e., 68.4 g of TTIP was added in total. The silver content of the final product was 6.5 wt. % and the ruthenium content was 0.3 wt. % (relative to 0 wt. % residual moisture) determined by ICP-OES. The powder thus obtained appeared light gray to the human eye. After filling a colorless snap-cap vial to a fill height of 1 cm, a spectrophotometer (ColorLite sph900 spectrometer) was used to measure the 56 L with a d / 8° measurement geometry through the glass bottom of the snap-cap vial placed on the measurement head of the spectrophotometer. * value was determined.

[0044] Inventive Example 5 (Preparation of Z-type particulate material): 10 g of the black powder from Reference Example 1 containing 15 wt. % residual moisture was dried at 105 °C / 300 mbar. The resulting dried powder was further processed in the same way as in Example 4. The silver content of the final product was 6.5 wt. % and the ruthenium content was 0.3 wt. % (relative to 0 wt. % residual moisture) were determined by ICP-OES. The powder thus obtained appeared light gray to the human eye. After filling a colorless snap-cap vial to a fill height of 1 cm, a spectrophotometer (ColorLite sph900 spectrometer) was used to measure the 56 L with a measurement geometry of d / 8° through the glass bottom of the snap-cap vial placed on the measurement head of the spectrophotometer. * value was determined.

Claims

1. 1. A particulate material Z comprising 15% to 50% by weight of particles X of a water-insoluble support material T comprising elemental silver and elemental ruthenium, and 50% to 85% by weight of a solid Y at least partially disposed on said particles X, wherein said solid Y is selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium (IV) oxyhydrate, titanium dioxide, titanium (IV) oxyhydrate, and combinations thereof.

2. 2. A particulate material Z according to claim 1, having a colour with a lightness L* in the range of 50 to 85.

3. 3. A particulate material Z according to claim 1 or 2, wherein the solid Y is formed as particles.

4. 2. The particulate material Z of claim 1, wherein the particles X have a silver+ruthenium weight fraction ranging from 0.1% to 50% by weight, with the silver:ruthenium weight ratio ranging from 1 part by weight to 2,000 parts by weight silver:1 part by weight ruthenium.

5. 2. The particulate material Z according to claim 1, wherein the carrier material T is water-swellable or capable of forming a hydrogel.

6. 2. The particulate material Z according to claim 1, wherein the support material T is selected from the group consisting of glass, nitrides, oxides, silicates, plastic materials, modified or unmodified naturally occurring polymers, carbon substrates, and wood.

7. 2. The particulate material Z according to claim 1, wherein the carrier material T is silicon dioxide, titanium dioxide, or cellulose.

8. 2. The particulate material Z according to claim 1, wherein the support material T is the same as or different from the solid Y.

9. 10. A method for preparing a particulate material Z according to claim 1, comprising contacting particles X of a water-insoluble support material T provided with elemental silver and elemental ruthenium with a C1-C4 alkoxide of at least one of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or titanium in the presence of water in an amount at least sufficient to completely hydrolyze said at least one C1-C4 alkoxide.

10. 10. The method of claim 9, wherein the at least one C1-C4 alkoxide is a titanium tetraalkoxide.

11. 10. The method of claim 9, wherein the water is provided as atmospheric moisture, as the moisture content of particles X, and / or in liquid form.

12. 10. The method of claim 9, wherein the product obtained after the complete hydrolysis is subjected to one or more further processing steps selected from the group consisting of solid-liquid separation, washing, drying, and grinding.

13. 10. The method of claim 9, wherein the particles X are directly contacted with the at least one alkoxide, or are first uniformly wetted with water, or are first suspended in an aqueous medium of water and a water-dilutable organic solvent.

14. 10. Use of a particulate material Z according to claim 1 or prepared according to the method of claim 9 as an additive for the antimicrobial treatment of materials or objects to be made antimicrobial.

15. 15. The use according to claim 14, wherein the material or object to be made antimicrobial has a chromatic or achromatic colour with a lightness L* in the range of 50-90.