Process for preparing fluxed up-conversion phosphors

Abstract

To provide an optimized process for the preparation of up-conversion phosphors.SOLUTION: There is provided a process for preparing an up-conversion phosphor of the general formula (I): A1-x-y-zB*yB2SiO4: Ln1x, Ln2z, I. The process includes the steps of: providing i) at least one lanthanoid salt; providing ii) a silicate or a silicon dioxide; providing iii) at least one alkaline earth metal salt and at least one alkali metal salt; providing iv) at least one specific amount of a flux; a) mixing components i), ii), iii) and iv) by grinding to obtain a mixture; or b) mixing components i), ii) and iii) and iv) in an organic polar solvent or the like which is not a protic solvent to obtain a mixture; c) pre-calcining the mixture; and d) calcining the mixture.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for preparing a flux-treated up-conversion phosphor, a flux-treated up-conversion phosphor, and its use in a coating having antibacterial properties.

Background Art

[0002] Humans are exposed daily to millions of microorganisms such as bacteria, fungi, and viruses. Many of these microorganisms are useful or even necessary. Nevertheless, in addition to these typically less harmful ones, there are bacteria, fungi, and viruses that cause disease or even death.

[0003] Microorganisms can be transmitted by daily contact with others or by contact with articles used by others. Especially in places where hygiene is considered, the surfaces are given an antibacterial finish. The fields of use are particularly the surfaces of medical devices and consumer goods in hospitals and outpatient health facilities for patients. In addition to these, there are surfaces in the public sphere, the food and beverage sector, and animal husbandry. The spread of pathogenic microorganisms is today a major problem everywhere, especially in the care sector, medicine, and when humans are active in enclosed spaces. A particular current risk is the increasing occurrence of so-called multi-drug resistant bacteria that are insensitive to standard antibiotics.

[0004] To reduce the risk of pathogen spread through contact surfaces, in addition to standard hygiene measures, antibacterial technologies and antibacterial materials are used. The use of chemical substances and physical methods can have a significant impact on the growth process of microorganisms. Examples of physical methods include heat, cold air, radiation, or ultrasonic waves. Among chemical methods, halogens, metal ions, organic compounds and dyes, and toxic gases are known.

[0005] While chemical and physical methods are generally highly effective in destroying microorganisms, their effects are short-lived, and chemical methods can promote the development of resistance and lead to the destruction of the protected surface, making them unsuitable for certain applications under certain circumstances. However, the greatest drawback, especially in the case of chemical organic substances, is the risk or toxicity to humans. Certain substances that have been used as disinfectants for many years, such as formaldehyde, are now suspected of causing cancer or being extremely harmful to the environment.

[0006] Surfaces with antimicrobial properties can make a significant contribution to solving these problems. Current standard methods for generating such antimicrobial properties primarily utilize active ingredients incorporated into materials, such as silver particles, copper particles, their metal oxides, or quaternary ammonium compounds. This often involves processing antimicrobial metals, antimicrobial metal oxides, or antimicrobial metal oxide mixtures to obtain nanoparticles, which are then mixed into paints, coatings, or polymer materials. The widespread use of metal particles is questionable because it is virtually impossible to assess the long-term effects of these heavy metals on humans and the environment.

[0007] For example, International Publication No. 2019 / 197076 discloses particles finished with layers containing both antimonstin oxide and manganese oxide. Those skilled in the art recognize that antimicrobial surfaces are created due to the electrochemical properties of metals, which generate microscale galvanic cells in the presence of moisture and produce a bactericidal effect through a microscale electric field.

[0008] Similarly, UV irradiation is known to be usable in medical and sanitation applications, for example, to disinfect water, gas, or surfaces. For instance, UV irradiation has long been used in drinking water treatment to reduce the number of facultative pathogenic microorganisms in water. This is preferably done using UV-C irradiation in the wavelength range of 200 nm to 280 nm. When using electromagnetic radiation of different wavelengths, the different absorption effects of amino acids / nucleic acids (e.g., DNA or RNA) present in various proteins, microorganisms, tissues, or cells, and the peptide bonds between individual acids should be considered. For example, DNA / RNA absorbs electromagnetic radiation well in the wavelength range of 200 nm to 300 nm, and particularly well at 250 nm to 280 nm, making this radiation particularly suitable for DNA / RNA inactivation. Therefore, such irradiation can inactivate pathogenic microorganisms (especially viruses, bacteria, yeasts, and fungi). Depending on the duration and intensity of irradiation, the structure of DNA or RNA can be destroyed. Thus, metabolically active cells can be inactivated and / or their ability to proliferate can be lost. The advantage of ultraviolet irradiation is that microorganisms cannot develop resistance to ultraviolet light. However, these physical methods require specific equipment and generally need to be repeated regularly by trained personnel, which makes it difficult to use them widely.

[0009] Furthermore, the use of so-called upconversion effects is also known, as is the direct irradiation of electromagnetic radiation from the ultraviolet wavelength range. This involves using phosphorescent particles that can convert electromagnetic radiation with wavelengths longer than ultraviolet, particularly visible light or infrared light, into electromagnetic radiation with shorter wavelengths, so that each phosphorescent particle can emit radiation of a desired wavelength.

[0010] German Patent No. 102015102427 relates to an emitter of electromagnetic radiation in the UV wavelength range. Fluorescent phosphorescent particles are embedded in a region near the surface of the material forming the emitter or in the coating of the emitter. Generally stated here is that the fluorescent phosphorescent particles are added directly to the coating formed on the material during processing, and that the specific material should have a suitable consistency or viscosity. German Patent No. 102015102427 does not mention suitable polymers and additives.

[0011] U.S. Patent Application Publication 2009 / 0130169A1 and International Publication 2009 / 064845A2 describe fluorite phosphorescent materials that can be introduced into polyvinyl chloride, acryloyl butadiene, polyolefins, polycarbonates, styrene, or nylon, which kill pathogenic microorganisms through their upconversion properties. These fluorite phosphorescent materials are prepared at temperatures of 1800–2900°C. While U.S. Patent Application Publication 2009 / 0130169A1 and International Publication 2009 / 064845A2 disclose compositions containing these fluorite phosphorescent materials that are claimed to have antimicrobial activity, they do not provide evidence of upconversion properties or microbiological experiments. The methods disclosed in these documents do not produce fluorite phosphorescent materials with upconversion properties, but instead yield amorphous and glassy products. Furthermore, U.S. Patent Application Publication No. 2009 / 0130169A1 and International Publication No. 2009 / 064845A2 do not mention the compatibility of components in the coating composition or the properties of the coating surface, such as a paint surface. However, the appearance of the coating surface is of paramount importance to consumers.

[0012] The requirements for coatings and paints are diverse. In principle, a coating layer or paint coating has two tasks or functions: protection and decoration. Hereafter, when the term "coating layer" is used, both types of coatings are intended. They decorate, protect, and preserve materials such as wood, metal, or plastic. Therefore, on the one hand, a bright, glossy coating layer is required, while on the other hand, a continuous coating layer is needed to ensure chemical and mechanical stability, a certain degree of slipperiness in the coating, or a specific feel.

[0013] In contrast to International Publication No. 2009 / 064845A2, Patent Application PCT / EP2020 / 077798 discloses a fluorite phosphorescent material exhibiting upconversion and its preparation. When irradiated with electromagnetic radiation having lower energy and longer wavelengths in the range of 2000 nm to 400 nm, particularly in the range of 800 nm to 400 nm, such a fluorite phosphorescent material can emit electromagnetic radiation having higher energy and shorter wavelengths in the range of 400 nm to 100 nm, preferably in the range of 300 nm to 200 nm, and as a result they are suitable for use as antimicrobial fluorite phosphorescent materials in coating layers.

[0014] For example, European Patent No. 3929254 describes a composition comprising at least one film-forming polymer, at least one upconversion phosphorescent material as taught in PCT / EP2020 / 077798, optionally at least one additive, and optionally at least one curing agent. Coating layers containing these phosphorescent materials have been shown to have antimicrobial activity without significantly impairing other properties, particularly storage stability.

[0015] However, it has been found that the phosphorescent materials prepared by the method of PCT / EP2020 / 077798 exhibit a non-uniform particle size distribution, which presents certain challenges when incorporating these phosphorescent materials into a coating matrix. While an antimicrobial coating layer is provided by the teachings of European Patent No. 3929254, it would be even more desirable if the intensity of the phosphorescent material's luminescence could be increased.

[0016] In the unpublished European Patent Application No. 21167984.0, it is proposed to use a fluorescent phosphorescent material prepared with at least one halogen-containing flux for the manufacture of a coating having antimicrobial properties, and the coating is At least one film-forming polymer, Optionally, at least one additive, Optionally, at least one hardener, At least one upconversion fluorescent phosphor of general formula (I) A 1-x-y-z B* y B2SiO4:Ln 1 x, Ln 2 z, I (In the formula, x = 0.0001 - 0.0500; z = 0.0000 or z = 0.0001 to 0.3000, where y = x + z; A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, where B is either the same as B* or B is not the same as B*, preferably B and B* are not the same; Ln 1 It is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd); Ln 2 This includes (selected from gadolinium (Gd)). In this case, a maximum of 3.5% by weight of flux is used relative to the total amount of reactants.

[0017] Therefore, it would be desirable to improve the fluorescent phosphorescent material and further optimize the method for its preparation, starting from the unpublished European Patent Application No. 21167984.0.

[0018] Those skilled in the art are aware of a wide variety of fluxes from the prior art, including halides, carbonates, sulfates, oxides, and borates of ammonium, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, lead, lanthanum, lutetium, aluminum, bismuth, and boric acid, where applicable. Their applications in the field of metallurgy, for example, to promote crystal growth or to suppress the formation of foreign phases, are also known.

[0019] Treatment with flux is also called fluxing, meaning the product is flux-treated. [Prior art documents] [Patent Documents]

[0020] [Patent Document 1] International Publication No. 2019 / 197076 Pamphlet [Patent Document 2] German Patent No. 102015102427 [Patent Document 3] U.S. Patent Application Publication No. 2009 / 0130169A1 [Patent Document 4] International Publication No. 2009 / 064845A2 Pamphlet [Patent Document 5] PCT / EP2020 / 077798 [Patent Document 6] European Patent No. 3929254 [Patent Document 7] Pre-publication European Patent Application No. 21167984.0 Specification [Overview of the project]

Problems to be Solved by the Invention

[0021] Surprisingly, the object was achieved by the method described in the main claim.

Means for Solving the Problems

[0022] General formula (I) A 1-x-y-z B* y B2SiO4:Ln 1 x, Ln 2 z, I (wherein, x = 0.0001 - 0.0500; z = 0.0000 or z = 0.0001 - 0.3000, provided that y = x + z; A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, B is the same as B* or B is not the same as B*, preferably B and B* are not the same; Ln 1 is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd); Ln 2 is selected from gadolinium (Gd)) is a method for preparing an upconversion phosphor of -i) at least one lanthanide salt selected from lanthanide nitrates, lanthanide carbonates, lanthanide carboxylates, preferably lanthanide acetates, lanthanide sulfates, lanthanide oxides, particularly preferably Pr6O 11 and / or Gd2O3, wherein the lanthanide ions in the lanthanide oxide or lanthanide salt are selected from praseodymium, gadolinium, erbium, and neodymium, and in the case of codoping, at least two of these, step, -ii) A step of preparing a silicate, preferably a silicate salt, particularly preferably an alkali metal salt of a silicate, or silicon dioxide, -iii) A step of preparing at least one alkaline earth metal salt and at least one alkali metal salt, preferably alkali metal silicates or alkali metal carbonates, preferably salts of lithium salts, preferably lithium silicate, particularly preferably lithium carbonate, calcium carbonate and sodium carbonate, selected from lithium salts or lithium compounds, and optionally selected from sodium salts and potassium salts, -iv) A step of preparing at least one flux selected from the group consisting of ammonium halides, preferably ammonium chloride, alkali metal halides, preferably sodium chloride, sodium fluoride, sodium bromide, lithium fluoride or lithium chloride, alkaline earth metal halides, preferably calcium chloride or calcium fluoride, and lanthanide halides, preferably praseodymium fluoride or praseodymium chloride, -a) A step of mixing components i), ii), iii), and iv) by grinding to obtain a mixture, -b) The step of mixing components i), ii), iii), and iv) by grinding in an organic polar solvent that is not a protic solvent or a nonpolar solvent to obtain a mixture; -c) In order to remove organic components, the mixture from b) is pre-calcined at 600-1000°C in an air atmosphere for at least 1 hour, preferably 2 hours or more, to obtain a pre-calcined mixture, and optionally cooled to room temperature. -d) The step of firing the mixture from a) or the pre-calcined mixture from c) at a temperature of 600 to less than 1000°C, preferably 650 to 900°C, for at least 3 hours, preferably at least 12 hours. -e) Preferably, after cooling the material, obtain a silicate-based upconversion fluorescent phosphorescent material of general formula (I), Includes, A method has been proposed in which at least 3.5% by weight of flux relative to the total amount of reactants is used.

[0023] Upconversion fluorescent phosphorescent materials have been found to have improved properties, such as specific surface area.

[0024] A further advantage of the present invention lies in its operational safety aspects. By increasing the amount of flux, the use of reducing gases in the firing step can be made completely unexpectedly unnecessary. Reducing gases are, for example, a CO-containing atmosphere or a forming gas, preferably an argon-hydrogen mixture or a nitrogen-argon mixture (97 / 3 and 95 / 5). Such reducing gases are undesirable for reasons of occupational safety, health protection, and environmental protection. Ensuring occupational safety for those involved in the use of these gases requires taking precautionary measures, for example, by spending on equipment, which then incurs financial costs.

[0025] Preferably, the method can be carried out in an air atmosphere.

[0026] Preferably, in the method according to the present invention, the amount of flux is 50.0% by weight or less, preferably 10.0% by weight or less, and particularly preferably 4.0% by weight or less, relative to the total amount of reactants.

[0027] The particle size distribution of the flux-treated phosphorescent material according to the present invention resembles a Gaussian distribution, which indicates uniform particle size. Therefore, its incorporation into a coating matrix is ​​significantly easier and more advantageous. As a result, coating properties, such as the appearance of the coating surface (e.g., gloss, feel, and texture), are considered to be improved.

[0028] The intensity of light emission from upconverted fluorescent phosphors can also be achieved through simple technical implementation.

[0029] The preferred silicon dioxide used may be products manufactured by Evonik under the trade names Aerosil® 300, 200, OX50, 200V, and 300V.

[0030] Preferably, the halogen-containing flux used is at least one substance from the group consisting of ammonium halides, alkali metal halides, alkaline earth metal halides, and lanthanides. Surprisingly, it has been found that halides from these groups produce upconversion phosphorescent materials with higher luminescence intensity than those using other fluxes.

[0031] The halogen is preferably a fluoride or chloride.

[0032] The alkali metals are preferably potassium, sodium, and lithium.

[0033] The lanthanide is preferably praseodymium.

[0034] The alkaline earth metal is preferably calcium or strontium.

[0035] The fluorescent phosphorescent material is preferably doped with praseodymium in the method according to the present invention.

[0036] The fluorescent phosphorescent material is preferably doped with praseodymium and co-doped with gadolinium in the method according to the present invention.

[0037] The present invention provides a method obtained by the present invention for general formula (I) A 1-x-y-z B* y B2SiO4:Ln 1 x, Ln 2 z, I (In the formula, x = 0.0001 - 0.0500; z = 0.0000 or z = 0.0001 to 0.3000, where y = x + z; A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, and B is either the same as B* or B is not the same as B*, preferably B and B* are not the same; Ln 1 It is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd); Ln 2 This is an upconversion fluorescent phosphor (selected from gadolinium (Gd)) measured in accordance with DIN 66131:1993-07, with a range of 1 to 500 m. 2 / g, preferably 5-250m 2 / g, particularly preferably 10-100m 2 The present invention further provides an upconversion fluorescent phosphorescent material having a specific surface area determined by gas absorption by Brunauer, Emmett and Teller (BET) at / g.

[0038] The phosphorescent material is preferably a crystalline silicate doped with lanthanide ions containing at least one alkali metal ion and at least one alkaline earth metal ion, or consists of a crystalline silicate.

[0039] The phosphorescent material is preferably doped with praseodymium and co-doped with gadolinium.

[0040] The fluorite phosphorescent material is preferably partially or completely crystalline. Therefore, it is preferable that the fluorite phosphorescent material is not at least completely amorphous. For this reason, it is preferable that the fluorite phosphorescent material is not an amorphous solidified molten material (glass). The fluorite phosphorescent material has a crystal fraction of preferably more than 50%, preferably more than 70%, and particularly preferably more than 85%, calculated using an X-ray powder diffraction pattern and according to the calculation formula (DOC = degree of crystallinity).

[0041]

number

[0042] I will now explain the method.

[0043] The phosphorescent material is preferably of general formula (Ia) A 1-x-y-z B* y B2SiO4:Pr x, Gd z, (Ia) (In the formula, A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, and B is either the same as B* or B is not the same as B*, preferably B and B* are not the same; x = 0.0001 - 0.0500; The compounds are selected from those where z = 0.0000 or z = 0.0001 to 0.3000, where y = x + z.

[0044] B* helps to equilibrium the charge of the praseodymium or gadolinium substitution here.

[0045] Here, A can represent one element from the group consisting of Mg, Ca, Sr, and Ba, or a combination of two or more elements from this group, i.e., A = (Mg a1 Ca a2 Sr a3 Ba a4 ) and in the formula 0≦a1≦1, 0≦a2≦1, 0≦a3≦1, 0≦a4≦1, where a1+a2+a3+a4=1. Therefore, A is, for example (Ca 0.9 Sr 0.1 ) can represent.

[0046] The fluorescent phosphorescent material is preferably of general formula (II) (Ca 1-a Sr a ) 1-2b Ln b Na b Li2SiO4II (In the formula, Ln is selected from the group consisting of praseodymium, gadolinium, erbium, neodymium, preferably praseodymium; a = 0.0000 to 1.0000, preferably 0.0000 to 0.1000, and especially 0.0000; A compound is selected from those in which b = 0.0001 to 0.5000, preferably 0.0001 to 0.1000, and particularly 0.0050 to 0.0500.

[0047] Here, Ln may represent a single element from the group consisting of praseodymium, gadolinium, erbium, and neodymium, or a combination of two elements from this group, i.e., Ln = (Ln 1 x Ln 2 y ) may also be expressed as, in the formula, Ln 1 and Ln 2 x is selected from the group consisting of praseodymium, gadolinium, erbium, and neodymium, and x and y are as defined for equations (I) and (Ia).

[0048] Ln 1 It is useful for doping. It is preferable to use praseodymium for doping. Ln 2 This is useful for any co-doping. It is preferable to use gadolinium for any co-doping. It is preferable that the phosphorescent material is not co-doped. In other words, it is preferable that Ln represents one element from the group consisting of praseodymium, gadolinium, erbium, and neodymium.

[0049] The phosphorescent material of a firefly is given by general formula (IIa) Ca 1-2b Pr b Na b Li2SiO4(IIa) It is even more preferable that the compound be selected from the compounds of the formula (wherein b = 0.0001 to 0.5000, preferably 0.0001 to 0.1000, and particularly 0.0050 to 0.0500).

[0050] The phosphorescent material is Ca 0.98 Pr 0.01 Na 0.01 Li2SiO4 or Ca 0.94 Pr 0.03 Na0.03 Li2SiO4 or Ca 0.90 Pr 0.05 Na 0.05 It is extremely preferable that the material be Li2SiO4.

[0051] Preferably, the upconversion fluorescent phosphorescent material according to the present invention contains a halogen corresponding to the halide of the flux.

[0052] The fluorescent phosphorescent material is a fluorescent phosphorescent material that converts electromagnetic radiation having lower energy and longer wavelengths, preferably in the range of 2000 nm to 400 nm, and particularly in the range of 800 nm to 400 nm, into electromagnetic radiation having higher energy and shorter wavelengths, preferably in the range of 400 nm to 100 nm, and preferably in the range of 300 nm to 200 nm. The maximum emission intensity of the electromagnetic radiation having higher energy and shorter wavelengths is at least 1.10 3 Count / (mm) 2 *s), preferably 1·10 4 Count / (mm) 2 *s) higher, especially preferably 1·10 5 Count / (mm) 2 *A higher intensity than s is even more preferable. To determine these indicators, it is preferable that the emission is excited by a laser, particularly a laser having an output of 75 mW at 445 nm and / or 150 mW at 488 nm.

[0053] The fluorescent phosphorescent body according to formula (II) preferably has XRPD signals in the ranges of 23°2θ to 27°2θ and 34°2θ to 39.5°2θ, and the signals have Bragg-Brentano geometry and Cu-K α It is determined by radiation. Details of the measurement method can be found in the unpublished European patent applications EP19202910.6 and PCT / EP2020 / 077798.

[0054] PCT / EP2020 / 077798 deals only with the preparation of phosphorescent materials, particularly those of formula (I), formula (Ia), and formula (II), without the addition of flux.

[0055] Further detailed embodiments of the method can be found in EP19202910.6 and PCT / EP2020 / 077798, where at least 3.5% flux relative to the total amount of reactants is used in the method according to the present invention.

[0056] Remarkably, it was possible to modify known methods in a sophisticated way, resulting in optimized upconversion fluorescent phosphors with exceptionally unexpected properties in terms of increased particle size distribution, luminescence intensity, and specific surface area.

[0057] Adding flux exceeding 3.5 wt% is thought to lead to a more uniform crystallization / melting process. This method allows for a more uniform distribution of praseodymium ions within the lattice, resulting in more uniform doping. Furthermore, a more uniform melting process leads to sintering of the particle surface, thus reducing the specific surface area of ​​the upconversion phosphorescent material. Empirically, particles with a smaller specific surface area can be incorporated into the coating matrix with lower energy input.

[0058] Surprisingly, the fluorescent phosphorescent materials according to the present invention, prepared in accordance with the teachings of EP19202910.6 and PCT / EP2020 / 077798, have been found to possess the necessary upconversion properties that contribute to antimicrobial activity. In other words, these fluorescent phosphorescent materials can convert electromagnetic radiation with wavelengths exceeding UV radiation, particularly visible or infrared light, into electromagnetic radiation with shorter wavelengths, especially in regions where, for example, microbial DNA or RNA can be destroyed or mutated. Therefore, these fluorescent phosphorescent materials are very well suited to the compositions according to the present invention.

[0059] It should be noted here that, following the teachings of EP19202910.6 and PCT / EP2020 / 077798, subsequent grinding with a fluorescent phosphorescent material can be used to first achieve uniformity of particle size, and then achieve the desired particle size. However, in this case, the energy input will be higher, and the grinding method will last longer due to its heterogeneity and particle size distribution after preparation.

[0060] The present invention • At least one film-forming polymer, • Optionally, at least one additive, • At least one hardener of your choice and The invention also provides the use of a fluorescent phosphorescent material prepared by the present invention for producing a coating having antimicrobial properties, including [specific material].

[0061] The selection of film-forming polymers plays a crucial role here. In principle, all film-forming polymers known from prior art are useful.

[0062] The film-forming polymer is preferably reactive with an isocyanate-containing curing agent and optionally has a catalyst-catalyzed functional group, preferably acidic hydrogen.

[0063] Advantageously, the film-forming polymer is selected from the group consisting of hydroxy-functional acrylate polymers, hydroxy-functional polyester polymers, and / or hydroxy-functional polyether polymers, hydroxy-functional cellulose derivatives, amino-functional aspartate polymers, or polyester polymers that react with an isocyanate-containing curing agent.

[0064] The film-forming polymer preferably has low resonance.

[0065] Those skilled in the art recognize the physical interactions at a surface. Depending on the material and its surface, multiple effects occur at the surface when light is incident. Incident light is partially absorbed, partially reflected, and also scattered depending on the material surface. Light may also be absorbed first and then re-emitted. In the case of opaque, translucent, or transparent materials, light can also penetrate the body (transmission). In some cases, light is polarized or even diffracted at the surface. Some objects can emit light (illuminated displays, LED segments, display screens), or even emit fluorescence or phosphorescence (afterglow) in different colored light.

[0066] In the context of this invention, "low resonance" means that the film-forming polymer has low absorption, reflection, reduction, and scattering in the UV region. In contrast, transmittance should preferably be significant.

[0067] This is because, surprisingly, the film-forming polymer according to the present invention, which has low resonance, has been found to have improved antibacterial activity, as more electromagnetic radiation with lower energy and higher wavelengths in the range of 2000 nm to 400 nm, particularly in the range of 800 nm to 400 nm, is transmitted, and as a result, more electromagnetic radiation with higher energy and shorter wavelengths in the range of 400 nm to 100 nm, preferably in the range of 300 nm to 200 nm, can be converted.

[0068] It has been found that the higher the permeability, the greater the release, and this is essential for antibacterial action.

[0069] Preferably, the transmittance of the film-forming polymer is measured at a wavelength of 260 nm and is at least 75%, preferably at least 80%, and particularly preferably at least 85%.

[0070] Preferably, the transmittance of the film-forming polymer is measured at a wavelength of 500 nm and is at least 75%, preferably at least 80%, and particularly preferably at least 85%.

[0071] For example, it should be noted that transmittance may be defined at different wavelengths. See Figure 1. In this invention, a wavelength of 260 nm is selected as an example of an emitted wavelength and a wavelength of 500 nm as an example of an excitation wavelength, which are responsible for upconversion on the one hand and for a considerable degree of antibacterial activity on the other hand.

[0072] For example, in the case of 100% transmittance measured at a wavelength of 260 nm, the same amount of radiation is converted and emitted. In other words, there is no loss due to absorption, scattering, etc. In the case of 80% transmittance measured at a wavelength of 260 nm, 20% is not transmitted, probably due to absorption, reflection, attenuation and / or scattering. Therefore, only 80% of the radiation at a wavelength of 260 nm can be emitted.

[0073] This important finding is crucial in the selection of film-forming polymers. For example, polymers with 0% transmittance are unsuitable for the curable compositions according to the present invention. They do not transmit electromagnetic radiation of lower energy and higher wavelength, and therefore, the phosphorescent materials present in the composition cannot convert this electromagnetic radiation into electromagnetic radiation of higher energy and shorter wavelength to emit the electromagnetic radiation necessary for antibacterial action.

[0074] Preferably, the composition according to the present invention has a transmittance of at least 75%, preferably at least 80%, and particularly preferably at least 85%, as measured at 260 nm.

[0075] Preferably, the composition according to the present invention has a transmittance of at least 75%, preferably at least 80%, and particularly preferably at least 85%, as measured at 500 nm.

[0076] The transmittance curve is preferably measured using an Analytik Jena "Specord 200 Plus" twin-beam UV / VIS spectrometer. A holmium oxide filter is used for internal wavelength calibration. Monochromatic light from a deuterium lamp (UV range) or a tungsten-halogen lamp (visible range) passes through the sample. The spectral range is 1.4 nm. The monochromatic light is split into a measurement channel and a reference channel, allowing for direct measurement relative to a reference sample. The radiation transmitted through the sample is detected by a photodiode and processed to form an electrical signal.

[0077] It is conceivable to use compositions with a low transmittance of less than 70%. They would likely still possess antibacterial properties, but their efficiency would be only moderate.

[0078] The phosphorescent material preferably has an average particle size of d50 = 0.1 to 50 μm, preferably d50 = 0.1 to 25 μm, and particularly preferably d50 = 0.1 μm to 5 μm, when measured according to ISO 13320:2020 and USP 429 using, for example, a Horiba LA-950 laser particle size analyzer.

[0079] To efficiently incorporate and / or stabilize the fluorescent phosphorescent material in the composition according to the present invention, various additives can preferably be added.

[0080] The additive is preferably selected from the group consisting of dispersants, rheological aids, leveling agents, wetting agents, defoaming agents, and UV stabilizers.

[0081] Surprisingly, it was found that adding an additive to the composition according to the present invention reduced its transmittance.

[0082] Therefore, in further embodiments in which additives are used, the compositions according to the present invention have a transmittance of preferably at least 70%, preferably at least 75%, and particularly preferably at least 80%, as measured at 260 nm.

[0083] Therefore, in further embodiments in which additives are used, the compositions according to the present invention have a transmittance of preferably at least 70%, preferably at least 75%, and particularly preferably at least 80%, as measured at 500 nm.

[0084] Preferably, the composition according to the present invention comprises a curing agent selected from the group of aliphatic or alicyclic isocyanates.

[0085] Examples of isocyanate-containing curing agents include monomer isocyanates, polymer isocyanates, and isocyanate prepolymers. Polyisocyanates are preferred over monomer isocyanates due to their lower toxicity. Examples of polyisocyanates include isocyanurates, uretdione, and biuret based on diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). Examples of commercially available products include Covestro's trade name DESMODUR® or Evonik Industries' VESTANAT. Known products include Covestro's DESMODUR® N3400, DESMODUR® N3300, DESMODUR® N3600, DESMODUR® N75, DESMODUR® XP2580, DESMODUR® Z4470, DESMODUR® XP2565, and DESMODUR® VL. Further examples include Evonik Industries' VESTANAT® HAT 2500 LV, VESTANAT® HB 2640 LV, or VESTANAT® T 1890E. Examples of isocyanate prepolymers include Covestro's DESMODUR® E XP 2863, DESMODUR® XP 2599, or DESMODUR® XP 2406. Further isocyanate prepolymers known to those skilled in the art may be used.

[0086] The use of a catalyst for curing is conceivable. The following catalysts, selected from organic Sn(IV), Sn(II), Zn, Bi compounds, or tertiary amines, may be used. It is preferable to use a catalyst selected from the group consisting of organotin catalysts, titanates or zirconates, organometallic compounds of aluminum, iron, calcium, magnesium, zinc, or bismuth, Lewis acids or organic acids / bases, linear or cyclic amidines, guanidines or amines, or mixtures thereof.

[0087] The curing catalyst used is preferably an organotin compound, such as dibutyltin dilaurate, dibutyltin diacetylacetonate, dibutyltin diacetate, dibutyltin dioctoate, or dioctyltin dilaurate, dioctyltin diacetylacetonate, dioctyltin diketanoate, dioctylstannoxane, dioctyltin dicarboxylate, or dioctyltin oxide, preferably dioctyltin diacetylacetonate, dioctyltin dilaurate, dioctyltin diketanoate, dioctylstannoxane, dioctyltin dicarboxylate, or dioctyltin oxide, and particularly preferably dioctyltin diacetylacetonate and dioctyltin dilaurate. Furthermore, zinc salts such as zinc octoate, zinc acetylacetonate, and zinc 2-ethyl caproate, or tetraalkylammonium compounds such as N,N,N-trimethyl-N-2-hydroxypropylammonium hydroxide, N,N,N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate, or choline 2-ethylhexanoate can also be used. The use of zinc octanoate (zinc 2-ethylhexanoate) and tetraalkylammonium compounds is preferred, and the use of zinc octanoate is particularly preferred.More preferably are bismuth catalysts, such as TIB Kat (TIB Mannheim) or Borchi® catalysts, titanates, such as titanium(IV) isopropoxide, iron(III) compounds, such as iron(III) acetylacetonate, aluminum compounds, such as aluminum triisopropoxide, aluminum tri-sec-butoxide and other alkoxides, as well as aluminum acetylacetonate, calcium compounds, such as ethylenediaminetetraacetate disodium or calcium diacetylacetonate, or otherwise amines, such as triethylamine, tributylamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]unde-7-ene, 1,5-diazabicyclo[4.3.0]nona-5-ene, N,N-bis(N,N-dimethyl-2-aminoethyl)methylamine, N,N-dimethylcyclohexylamine, N,N-dimethylphenylamine, N-ethylmorpholine, and the like. Organic or inorganic Brønsted acids, such as acetic acid, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, or benzoyl chloride, hydrochloric acid, phosphoric acid, and their monoesters and / or diesters, such as butyl phosphate, (iso)propyl phosphate, and dibutyl phosphate, are also preferred catalysts. Guanidine-containing organic and organosilicon compounds are also preferred. Of course, it is also possible to use a combination of two or more catalysts. Furthermore, as described in International Publication No. 2005 / 100482, it is also possible to use photolatent bases as catalysts.

[0088] The curing catalyst is used in an amount of preferably 0.01% to 5.0% by weight, preferably 0.05% to 4.0% by weight, and particularly preferably 0.1% to 3% by weight, relative to the total weight of the curable composition.

[0089] In the case of film-forming polymers that harden by physical drying, the addition of a reactive curing agent is not required.

[0090] The compositions according to the present invention may preferably be used as a 1K (one-component) coating system or a 2K (two-component) coating system, a melamine baked coating system, or at room temperature or high temperature.

[0091] Preferably, a coating produced from the composition according to the present invention has antimicrobial activity against bacteria, yeast, mold, algae, parasites, and viruses.

[0092] A coating manufactured according to the present invention is preferably, - Against pathogens of hospital-acquired infections, preferably Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Enterobacter, Corynebacterium diphtheriae, Candida albicans, rotavirus, and bacteriophages; - Against facultative pathogenic environmental organisms, preferably Cryptosporidium parvum, Giardia lamblia, amoebas (Acanthamoeba spp., Naegleria spp.), Escherichia coli, coliform bacteria, fecal streptococci, Salmonella spp., Shigella spp., Legionella spec., Pseudomonas aeruginosa, Mycobacterium spp., and enteroviruses (e.g., polio and hepatitis A viruses); - Pathogens in food and beverages, preferably Bacillus cereus, Campylobacter spp., Clostridium botulinum, Clostridium perfringens, Cronobacter spp., Escherichia coli, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, Vibrio spp., Yersinia enterocolitica, bacteriophages; It has antibacterial properties against [the target of the antimicrobial agent].

[0093] It was found that the integration of the upconversion fluorescent phosphor in the present invention has been significantly improved.

[0094] Upconversion and phosphorescent material are used as synonyms.

[0095] The present invention further provides the use of a fluorescent phosphorescent material in compositions for the manufacture of dispersions, mill bases, adhesives, trowel compounds, primers, paints, coatings, or printing inks, inkjet printers, pulverized resins, or pigment concentrates.

[0096] The use of the composition according to the present invention for the manufacture of coatings having antibacterial properties is preferred.

[0097] Here, a coating having antibacterial properties means that the coating has an antibacterial surface that restricts or prevents the growth and proliferation of microorganisms.

[0098] Surprisingly, it was also found that the coating according to the present invention possesses chemical and mechanical stability. Chemical and mechanical stability is particularly important because antimicrobial coatings are frequently used in places where regular disinfection and further hygiene measures are required.

[0099] The present invention relates to a method for forming an antibacterial coating on a substrate, a. At least one film-forming polymer containing a functional group reactive with an isocyanate-containing curing agent, which is optionally catalyzed by a catalyst, b. At least one fluorescent phosphorescent body of formula (II), c. A curing agent containing an isocyanate functional group The present invention also provides a method comprising applying a curable film-forming composition containing the above to a substrate.

[0100] Preferably, the substrate is a metal, a mineral substrate (e.g., concrete, natural rock, or glass), a cellulose substrate, wood or hybrids thereof, a dimensionally stable plastic, and / or a thermosetting resin.

[0101] The term "dimensionally stable plastics" is not comprehensive, but is understood to refer to the following polymers: acrylonitrile-butadiene-styrene (ABS), polyamide (PA), polylactic acid (PLA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), polyether ether ketone (PEEK), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene (PE).

[0102] Preferably, the primer composition may be applied to the substrate before applying the curable film-forming composition.

[0103] Preferably, the curable composition according to the present invention is used for coating substrates in sanitary facilities and hospitals, as well as in the food and beverage industry.

[0104] This includes all environments in the public sphere, such as schools, nursing homes, industrial kitchens, or daycare centers.

[0105] A further invention is an article at least partially, preferably completely, coated with the curable composition according to the present invention.

[0106] Please note that the terms "antibacterial effect," "antibacterial efficacy," "antibacterial action," and "antibacterial properties" are used synonymously here.

[0107] It should be noted that articles according to the present invention may preferably have antimicrobial activity even without the release of antimicrobial active ingredients, provided that the coating contains the specific fluorite phosphorescent material described in the claims. Thus, the subsequent elimination of microorganisms is physical. Therefore, such materials are not subject to biocides (Regulation (EU) No 528 / 2012 of 22 May 2012, as of the current text in 2019).

[0108] The following examples are useful only to those skilled in the art to illustrate the present invention and do not constitute any limitation on any of the claimed subject matter. [Brief explanation of the drawing]

[0109] [Figure 1] Figure 1 shows the emission spectra of Examples 1 and 2 and the comparative example. The phosphorescent material exhibited the desired wavelength range. [Examples]

[0110] method Particle size distribution in accordance with ISO 13320:2020 and USP 429, using a Horiba LA-950 laser particle size analyzer. Qualitative elemental analysis by EDX using Hitachi's Tabeltop 4000Plus, 15kV BSE detector, and 1000x magnification. Powder XRD: The X-ray powder diffraction pattern of the sample is Cu-K αThe data was recorded using a Bruker D2 Phaser powder diffractometer operating in Bragg-Brentano geometry, employing radiation and line-scan CCD detectors. The integration time was 20 seconds, and the step size was 0.017° 2θ. The emission spectrum was recorded using an Edinburgh Instruments FLS920 spectrometer equipped with a Coherent 488 nm continuous-wave OBIS laser and a Hamamatsu Peltier-cooled (-20°C) single-photon counting photomultiplier tube (R2658P). An edge filter was used to suppress secondary and higher-order reflections caused by the monochromator. BET surface area measurement in accordance with ISO 9277 and DIN 66131 using Quantachrome's Nova 2000e instrument. As described above in the section on powder XRD, the degree of crystallinity (DOC) provides information about the ratio of the crystalline area of ​​all components to the amorphous area in the powder diffraction pattern. The degree of crystallinity is calculated from the total area under the crystalline and amorphous fractions.

[0111]

number

[0112] Fluorescent phosphors Example 1 A fluorescent phosphorescent material according to the present invention containing 4% by weight of CaF2 as flux (Ca 0.98 Pr 0.01 Na 0.01 )Li2SiO4 CaCO34.12g, Li2CO33.11g, SiO22.52g, Na2CO30.02g, Pr6O 11 0.07 g and 20.4 g of CaF were mixed together. This mixture was calcined in air at 850°C for 6 hours to obtain the desired product. The phosphorescent material was removed for further measurement. BET: 3m 2 / g Particle size distribution: D 10 :3μm D 50 :9μm D 90 : 32 μm Crystallinity: 89%

[0113] Example 2 A fluorophosphor (Ca 0.98 Pr 0.01 Na 0.01 )Li2SiO4 containing 6 wt% CaF2 as a flux, according to the present invention 4.12 g of CaCO3, 3.11 g of Li2CO3, 2.52 g of SiO2, 0.02 g of Na2CO3, Pr6O 11 0.07 g and 0.62 g of CaF2 were mixed with each other. This mixture was calcined at 850 °C in air for 6 hours to obtain the desired product. The fluorophosphor was taken out for further measurement. BET: 2 m 2 / g Particle size distribution: D 10 : 3 μm D 50 : 10 μm D 90 : 60 μm Crystallinity: 90%

[0114] Comparative example: A fluorophosphor (Ca 0.98 Pr 0.01 Na 0.01 )Li2SiO4 containing 1.5 wt% CaF2 as a flux 4.12 g of CaCO3, 3.11 g of Li2CO3, 2.52 g of SiO2, 0.02 g of Na2CO3, Pr6O 11 0.07 g and 0.15 g of CaF2 were mixed with each other. This mixture was calcined at 850 °C in air for 6 hours to obtain the desired product. The fluorophosphor was taken out for further measurement. BET: 49 m 2 / g Particle size distribution: D10: 3 μm D50: 12 μm D90: 56 μm Crystallinity: 93%

[0115] The particle size distribution of the fluorescent phosphorescent material in the present invention (Examples 1 and 2) and the comparative example did not show a significant change. The addition of 4% by weight or 6% by weight of CaF2 significantly reduced the specific surface area (BET) of the fluorescent phosphorescent material according to the present invention (Examples 1 and 2) compared to the fluorescent phosphorescent material containing 1.5% by weight. The decrease in BET surface area, accompanied by a stable particle size distribution, indicates a decrease in porosity. The crystallinity of the fluorescent phosphorescent material did not significantly change as a result of increasing the addition of the CaF2 mixture.

[0116] All of the phosphorescent materials exhibited upconversion characteristics and antibacterial effects in the emission spectrum of the UV-C region. Incorporation of the phosphorescent materials according to the present invention into the coating matrix was far easier.

Claims

1. General formula (I) A １－ｘ－ｙ－ｚ B* ｙ B ２ SiO ４ :Ln １ ｘ， Ln ２ ｚ， I (In the formula, x=0.0001-0.0500; z=0.0000 or z=0.0001 to 0.3000, where y=x+z; A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, and B is the same as B* or B is not the same as B*; Ln １ is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd); Ln ２ is selected from gadolinium (Gd) 1. A method for preparing an upconversion phosphor of formula (I), comprising the steps of: i) providing at least one lanthanide salt or oxide selected from lanthanide nitrates, carbonates, carboxylates and sulfates, in which the lanthanide ions in said lanthanide oxide or salt are selected from praseodymium, gadolinium, erbium and neodymium, or in the case of co-doping, at least two of these; -ii) providing a silicate or silicon dioxide; -iii) providing at least one alkaline earth metal salt and at least one alkali metal salt; -iv) providing at least one flux selected from the group consisting of ammonium halides, alkali metal halides, alkaline earth metal halides, and lanthanide halides; - a) mixing components i), ii), iii) and iv) by grinding to obtain a mixture, or -b) mixing components i), ii) and iii) and iv) by grinding in an organic polar or non-polar solvent which is not a protic solvent to obtain a mixture; - c) pre-firing said mixture from b) at 600-1000°C under air atmosphere for at least 1 hour to obtain a pre-firing mixture, and optionally cooling to room temperature, also to remove said organic components; -d) calcining the mixture from a) or the pre-fired mixture from c) at a temperature of 600 to less than 1000°C for at least 3 hours; Including, 10. The method of claim 9, wherein at least 3.5 wt. % of the flux is used relative to the total amount of the reactants.

2. 2. The method of claim 1, wherein the amount of the flux is 50.0% by weight or less based on the total amount of the reactants.

3. 2. The method of claim 1, wherein the calcination (step d) is carried out under an air atmosphere.

4. 2. The method of claim 1, wherein the lanthanide is praseodymium.

5. 2. The method of claim 1, wherein the alkali metal is sodium or lithium.

6. 2. The method of claim 1, wherein the alkaline earth metal is calcium.

7. 2. The method of claim 1, wherein said phosphor is doped with praseodymium.

8. 2. A compound of general formula (I) obtainable by the method according to claim 1 A １－ｘ－ｙ－ｚ B* ｙ B ２ SiO ４ :Ln １ ｘ， Ln ２ ｚ， I (In the formula, x=0.0001-0.0500; z=0.0000 or z=0.0001 to 0.3000, where y=x+z; A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, and B is the same as B* or B is not the same as B*; Ln １ is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd); Ln ２ is selected from gadolinium (Gd), and have a luminance of 1 to 500 m, measured according to ISO 9277, DIN 66131. ２ / g of specific surface area as determined by gas adsorption according to Brunauer, Emmett and Teller (BET).

9. 9. The phosphor of claim 8, wherein the phosphor is doped with praseodymium and co-doped with gadolinium.

10. 9. The phosphor of claim 8, wherein the phosphor is a solidified melt of a crystalline silicate or a crystalline silicate doped with lanthanide ions, comprising at least one alkali metal ion and at least one alkaline earth metal ion.

11. 9. The phosphor of claim 8, wherein the phosphor is at least partially crystalline.

12. The phosphor has the general formula (Ia) A １－ｘ－ｙ－ｚ B* ｙ B ２ SiO ４ :Pr ｘ， Gd ｚ， (Ia) wherein A is selected from the group consisting of Mg, Ca, Sr, and Ba; B is selected from the group consisting of Li, Na, K, Rb, and Cs; B* is selected from the group consisting of Li, Na, and K, and B is the same as B* or B is not the same as B*; x=0.0001-0.0500; 9. The phosphor of claim 8, wherein the compound is selected from the group consisting of compounds in which z=0.0000 or z=0.0001 to 0.3000, provided that y=x+z.

13. The phosphor has the general formula (II) (1 １－ａ Sr ａ ) １－２ｂ Ln ｂ Na ｂ Li ２ SiO ４ II (In the formula, Ln is selected from the group consisting of praseodymium, gadolinium, erbium, and neodymium; a = 0.0000 to 1.0000; 9. The phosphor of claim 8, wherein b is selected from the group consisting of compounds of the formula (I) and (II), wherein b=0.0001 to 0.5000.

14. The phosphor has the general formula (IIa) Ca １－２ｂ Pr ｂ Na ｂ Li ２ SiO ４ (IIa) 9. The phosphor of claim 8, wherein the compound is selected from the group consisting of: wherein b=0.0001 to 1.

15. The phosphor is Ca ０．９８ Pr ０．０１ Na ０．０１ Li ２ SiO ４ or Ca ０．９４ Pr ０．０３ Na ０．０３ Li ２ SiO ４ or Ca ０．９０ Pr ０．０５ Na ０．０５ Li ２ SiO ４ 9. The phosphor of claim 8, wherein:

16. 9. The phosphor of claim 8, wherein the phosphor according to formula (II) has XRPD signals in the ranges from 23° 2θ to 27° 2θ and from 34° 2θ to 39.5° 2θ.

17. at least one film-forming polymer, optionally at least one additive, optionally at least one hardener; 10. Use of the phosphor of claim 8 for the manufacture of a coating having antibacterial properties, comprising:

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