Phosphor-containing Ink for Disinfection and Improvement of Photo-stability of Synthetic Polymers

Abstract

This specification describes a phosphor-containing ink composition for disinfecting the surface of a synthetic polymer and improving its light stability. In addition, a method for preparing the ink composition is described.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 366,582, filed on June 17, 2022, and U.S. Provisional Patent Application No. 63 / 366,576, filed on June 17, 2022, the entire contents of each of which are incorporated herein by reference in their entirety.

[0002] Technical Field The subject matter disclosed herein generally relates to phosphor - containing inks for disinfecting the surface of synthetic polymers and improving their light stability.

Background Art

[0003] Phosphor materials have the property of emitting ultraviolet light, visible light, and infrared light under the action of external excitation means such as irradiation with electromagnetic waves (e.g., electron beam, X - ray, ultraviolet light, visible light, etc.) or application of an electric field, and thus are used in many photoelectric converters or photoelectric conversion devices. Examples of such devices are light - emitting devices including white - light - emitting diodes, fluorescent lamps, electron - beam tubes, plasma display panels, inorganic electroluminescent displays, and scintillators. In particular, inorganic phosphors have been widely studied to meet the demand for low - voltage - stimulated lighting sources due to the increase in global energy consumption. Due to the advantages of being environmentally friendly, having a long lifespan, low energy consumption, high reliability, and high luminous efficiency, the latest white - light - emitting diodes (WLEDs) have replaced incandescent lamps with lower efficiency and conventional mercury - encapsulated fluorescent lamps.

[0004] Lanthanoids are often used as phosphors for light - emitting applications. For example, the shielded f - orbitals of praseodymium enable a long excited - state lifetime and a high luminescence yield. In fact, Pr 3+ is often a dopant ion used in red, blue, green, and ultraviolet phosphors.

Summary of the Invention

[0005] In one aspect, the subject matter disclosed herein relates to an ink composition comprising one or more inorganic phosphor dopants, a solvent, and a binder.

[0006] In another aspect, the subject matter disclosed herein relates to an ultraviolet curable ink composition comprising one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers.

[0007] In another aspect, the subject matter disclosed herein relates to an ink composition that has disinfecting properties upon exposure to an ultraviolet light source.

[0008] In another aspect, the subject matter disclosed herein relates to a synthetic polymer comprising a surface that is coated with an ink composition disclosed herein, the coating providing improved color stability to the synthetic polymer.

[0009] In another aspect, the subject matter disclosed herein relates to a method for disinfecting a surface that is coated with an ink composition disclosed herein, the method comprising exposing the surface to an ultraviolet light source, the exposure causing one or more inorganic phosphor dopants in the ink composition to emit photons that irradiate the surface, thereby disinfecting the surface.

[0010] In another aspect, the subject matter disclosed herein relates to a method for improving the color stability of a synthetic polymer comprising a surface that is coated with an ink composition disclosed herein, the method comprising exposing the surface to ultraviolet light, wherein one or more inorganic phosphor dopants in the ink composition absorb the ultraviolet light and then emit it as down-converted visible light.

[0011] In another aspect, the subject matter disclosed herein relates to a method of making an ink composition comprising one or more inorganic phosphor dopants, a solvent, and a binder, the method comprising contacting the solvent with the one or more inorganic phosphor dopants and the binder, whereby an ink composition is prepared.

[0012] In another aspect, the subject matter disclosed herein relates to a method of making an ultraviolet curable ink composition comprising one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers, the method comprising contacting the one or more inorganic phosphor dopants with the one or more photoinitiators and the one or more monomers, whereby an ultraviolet curable ink composition is prepared.

[0013] These and other aspects are described fully herein.

[0014] The above summary is provided for the purpose of summarizing some embodiments of the present disclosure to provide a basic understanding of some aspects of the present disclosure. Accordingly, it is to be understood that the above examples are illustrative only and are not to be construed as limiting the scope or gist of the present disclosure. It will be understood that the scope of the present disclosure encompasses many potential embodiments in addition to those summarized herein. Some of those embodiments will be described further below. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Some embodiments of the present disclosure have been described above using general terms. Reference will be made hereinafter to the accompanying drawings. These drawings are not necessarily drawn to scale.

[0016]

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DETAILED DESCRIPTION OF THE INVENTION

[0017] The subject matter described herein relates to an inorganic phosphor-containing ink composition for use in disinfecting the surface of a synthetic polymer composition or improving the color stability thereof. This ink composition can be printed on various surfaces, such as, but not limited to, thermoplastic plastics, and utilizes the luminescent properties of inorganic phosphor dopant materials.

[0018] Disinfection "Disinfection" refers to the reduction, inhibition, inactivation, destruction, and / or removal of microorganisms other than bacterial endospores. The methods described herein provide several advantages over the disinfection methods in the art. In fact, the state-of-the-art technical methods for disinfecting surfaces involve the application of expensive and heavy ultraviolet light sources. Prolonged exposure to these light sources can affect the substrate surface. Generally, in areas with high contact, prolonged exposure to pulsed ultraviolet light is required. Other disinfection methods in the art generally include wiping the surface with a disinfectant solution that loses its effectiveness in a short time. Furthermore, exposure to such chemicals can have unintended effects on the substrate surface.

[0019] As described herein, by incorporating an inorganic phosphor into an ink composition and then coating the ink composition onto a substrate surface, a luminescent surface of UV-C light (from 200 nm to 280 nm) can be obtained for disinfecting the coated substrate surface over a long period of time. After exposing the phosphor-containing ink coating surface to a UV excitation source, the ink coating emits photons over an adjustable period after the excitation light is removed. The phosphor in the ink coating directly absorbs ultraviolet light. The phosphor then emits radiative energy, and this energy disinfects the surface of the coated substrate. In this regard, the disinfection results from the coated substrate surface itself. Further, the disinfection method described herein is excellent in durability because the inorganic phosphor is uniformly incorporated into the ink and coated on the substrate surface, thereby minimizing degradation due to wear or exposure to surface chemicals. Further, the ink composition coated on the substrate surface positions the inorganic phosphor closer to the surface compared to embedding the inorganic phosphor in the substrate itself (e.g., a thermoplastic substrate) or incorporating it in other ways. The disinfection method described herein can significantly shorten the time required to disinfect the surface using conventional methods.

[0020] UV-C light is weak at the earth's surface because it is blocked by the ozone layer in the atmosphere. Many disinfection methods use short-wavelength ultraviolet light (ultraviolet C or UV-C) to kill or inactivate microorganisms by destroying nucleic acids and their DNA, making them unable to perform important cell functions. The inorganic phosphor in the phosphor-containing ink composition described herein emits such bactericidal UV-C light, which acts to disinfect the surface coated with the ink.

[0021] Color stability Synthetic polymers such as thermoplastic plastics generally undergo photooxidation when exposed to ultraviolet light in the presence of oxygen. When the polymer absorbs this ultraviolet radiation energy, since the energy of the ultraviolet light is greater than the dissociation energy of the carbon-carbon sigma bonds in the synthetic polymer, it may lead to bond cleavage. In fact, ultraviolet light has photon energies in the range of 6.2 eV to 4.4 eV. Conversely, the bond energy of a typical carbon-carbon sigma bond is only 3.8 eV. Therefore, when absorbing ultraviolet light such as UV-C light in the presence of oxygen, it may lead to dissociative oxidation of the bonds, which changes the molecular structure of the polymer. Such structural changes often involve unfavorable physical changes in the appearance of the polymer, such as discoloration (yellowing) and embrittlement.

[0022] Current solutions to address the discoloration and embrittlement often experienced by synthetic polymers exposed to ultraviolet light include the following: (1) using polymers with higher color stability in applications with high exposure to ultraviolet light, and / or (2) incorporating ultraviolet stabilizing additives into the synthetic polymer formulation. However, synthetic polymers exhibiting satisfactory color stability may lack appropriate mechanical properties such as impact durability and chemical resistance. Furthermore, additives used to improve the color stability of synthetic polymers often reduce the mechanical properties of the material, such as tensile strength. Such additives have also been shown to reduce the flammability of the material. Thus, there is a need in the art to stabilize the color of synthetic polymers exposed to ultraviolet light without reducing other material performance characteristics.

[0023] Exemplary implementations of the subject matter described herein overcome the limitations of the technology by incorporating an inorganic phosphor into an ink composition and coating this ink composition onto the surface of a synthetic polymer. The inorganic phosphor in the ink absorbs ultraviolet light and converts it into harmless visible light. The inorganic phosphors applied to the methods and ink compositions described herein are crystalline materials and have a lattice structure that imparts high light stability, as shown by the exemplary lattice structure of FIG. 7. For example, the regular and robust arrangement of atoms within the lattice improves the thermal stability of the phosphor. In these phosphors, a small percentage of metal "dopant" ions are incorporated into the lattice that will affect the excitation and emission characteristics of the phosphor. The inorganic phosphor dopants used herein refer to metal oxide or metal fluoride materials containing rare earths or transition metals. Since the inorganic phosphor material is a ceramic type material that only coats the surface of the synthetic polymer, it does not adversely affect the mechanical properties or flammability of the synthetic polymer material. Many phosphors strongly absorb ultraviolet light (high energy, short wavelength), which is accompanied by emission of light with a longer wavelength and lower energy than the light originally absorbed by the phosphor. This emission is generally in the visible range and is not destructive to the synthetic polymer. The process by which light is absorbed at one wavelength and subsequently emitted at a longer wavelength is known as "downconversion". The inorganic phosphors in the ink compositions described herein absorb high-energy ultraviolet light (180 nm to 360 nm) and emit the energy as "downconverted" visible light (200 nm to 700 nm), as shown, for example, by the excitation and emission spectra of the exemplary inorganic phosphors of FIG. 5.

[0024] As described herein, by incorporating different metal ions into the host lattice of a metal oxide or metal fluoride, the color of the emitted light energy can be adjusted. Combinations of different emission colors produce white / off-white light. For example, combinations of blue-yellow or blue-green-red emitters result in white / off-white emission. Such combinations of emission from the phosphors can be used to adjust the visual color of a solid.

[0025] Exemplary implementations of the subject matter described herein manage the effects of ultraviolet light on synthetic polymers by selectively incorporating inorganic phosphors into ink compositions that coat the surface of the synthetic polymers. The inorganic phosphors in the ink compositions absorb and down-convert visible light, providing a brighter appearance to the synthetic polymer material. A brighter appearance is the brightness perceived by a viewer.

[0026] Henceforth, the subject matter disclosed in this specification will be described in more detail. However, those skilled in the art related to the technology associated with the subject matter disclosed in this specification, who have benefited from the teachings presented in the foregoing description, will envision numerous modifications and other embodiments of the subject matter of the disclosure shown herein. Accordingly, it should be understood that the subject matter disclosed herein is not limited to the specific embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the claims. In other words, the subject matter described herein covers all alternatives, modifications, and equivalents. In fact, according to the various implementations described herein, such identified disinfection properties and improved light stability are not limited to phosphor-containing inks used in inkjet printing. As will be apparent to those skilled in the art in light of the present disclosure, such disinfection properties and improved light stability can also be employed in a variety of applications other than inkjet printing, or in some cases, in ink compositions. In fact, if a manufacturer can coat a substrate that has already been manufactured, it is often more convenient and in many cases more desirable than redesigning the materials used to manufacture such a substrate in order to embed such inorganic phosphors within the material to impart a desired functionality. For example, if colorant particles are routinely used to impart color to a surface, at least a portion of the colorant can be replaced with an inorganic phosphor capable of emitting bactericidal radiation, thereby imparting an antimicrobial / antipathogenic functionality to the surface instead (instead of color). In fact, the advantages of the phosphor-containing compositions of the present disclosure are not limited to printing applications, and depending on the needs of the industry and / or manufacturing, the composition can be adjusted to be applied by any number of coating techniques such as dip coating, spray / aerosolization, roller, or brush painting. As will be apparent to those skilled in the art, since the inorganic phosphor is present in an amount less than that of the colorant loading of the pigment coating, the formulation can be modified and / or balanced to support the application in order to obtain a stable liquid that is compatible with the application tool (e.g., paint gun, inkjet print head, etc.).

[0027] Unless otherwise specified, all technical and scientific terms used in this specification shall have the same meaning as commonly understood by one of ordinary skill in the art. All publications, patent applications, patents, and other references mentioned in this specification are hereby incorporated by reference in their entirety. If one or more of the incorporated references, patents, and similar materials differ from or conflict with this application, including but not limited to defined terms, term usage, or the described technology, this application shall prevail.

[0028] I. Definitions As used in this specification, "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the absence of a combination (i.e., "or") when interpreted alternatively.

[0029] The terms "approximately", "about", and "substantially" as used in this specification represent an amount close to the described amount that still performs or achieves the desired function. For example, in some embodiments, as the context indicates, the terms "approximately", "about", and "substantially" may refer to an amount that is 10% or less of the described amount. The term "generally" as used in this specification represents a value, amount, or characteristic that mainly includes or tends towards a particular value, amount, or characteristic.

[0030] As used herein, terms including conditions, such as, among others, "can", "could", "might", "may", "e.g.", etc., are generally, unless otherwise specified or understood otherwise in the context in which they are used, intended to convey that some embodiments include certain features, components, and / or steps, while other embodiments do not. Thus, such terms including conditions generally do not intend that a feature, configuration, and / or step is required in any way in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or steps are included or implemented in any particular embodiment, regardless of the presence or absence of the author's input or prompt. Terms such as "comprising", "including", "having", etc., are synonymous and are used inclusively and non-limitingly, and do not exclude additional elements, features, acts, operations, etc. The term "consisting of" and its grammatical variations are each synonymous and are used restrictively, excluding additional elements, features, acts, operations, etc. The term "consisting essentially of" and its grammatical variations are each synonymous and are semi-restrictive terms, indicating that the claimed item is limited to the components specified in that claim and does not materially affect the basic and novel characteristics of that claim. Additionally, the term "or" is used in an inclusive sense (not an exclusive sense), such that, for example, when used to connect listed elements, the term "or" means one, some, or all of the listed components.

[0031] As used herein, "contacting" refers to preparing an ink composition by contacting a solvent with one or more inorganic phosphor dopants and a binder, or preparing an ultraviolet curable ink composition by contacting one or more inorganic phosphor dopants with one or more photoinitiators and one or more monomers. In some embodiments, contacting can be assisted, for example, by the application of heat and / or pressure.

[0032] As used herein, a "coated surface" or a "coating" surface refers to a surface that has been treated with an ink composition disclosed herein and that includes at least one layer of the ink composition on the surface. In some embodiments, the coated surface includes only a single layer of the ink composition disclosed herein. In still other embodiments, the coated surface refers to a plurality of layers of the ink composition disclosed herein on the surface of a substrate. By way of non-limiting example, a first layer (e.g., an inner layer) of the ink composition can be applied to the surface of a substrate, followed by the application of one or more additional layers (e.g., outer layers) of the ink composition on the first layer. In yet another embodiment, one or more inner layers of such a multi-layer coated surface need not be exposed (e.g., activated) to ultraviolet light until the outer layer of the ink composition is exposed to ultraviolet light and the outer layer itself emits light, and until the inner layer emits light. One or more inorganic phosphor dopants in such one or more inner layers can emit light at a longer wavelength compared to the outer layer. In some embodiments, one or more inorganic phosphor dopants in such one or more inner layers can absorb the light emitted by the outer layer and then emit light at a longer wavelength. In yet another embodiment, the layers of the ink composition of the coated surface can have varying thicknesses. In some embodiments, the coated surface and one or more layers of the ink composition forming the coated surface can be continuous. In yet another embodiment, at least one of the coated surface and the layers of the ink composition forming the coated surface can be discontinuous.

[0033] As used herein, "improving color stability" refers to extending the color life of a synthetic polymer material and / or reducing the incidence of yellowing of the host material of a synthetic polymer caused by exposure to ultraviolet light, as compared to a polymer material without a coating of an ink composition containing one or more inorganic phosphor dopants. As described herein, an ink composition containing one or more inorganic phosphor dopants can be coated on the surface of a synthetic polymer. One or more inorganic phosphor dopants in the ink coating can absorb ultraviolet light, thereby reducing the impact of ultraviolet absorption on the color stability of the polymer. In the examples, the inorganic phosphor dopant absorbs more incident ultraviolet light than the synthetic polymer material underlying the ink composition, thereby offsetting the photooxidation and discoloration of the polymer material.

[0034] Such improved color stability can be visually measured by using a control synthetic polymer without a coating of the ink composition described herein ("control") and a synthetic polymer coated with the ink composition described herein ("test") and enabling UV exposure of both the control synthetic polymer and the test synthetic polymer. The change in color can be easily perceived by comparing the amount of color change between the control sample and the test sample. For example, a synthetic polymer coated with the ink composition described herein is said to have improved color stability if it shows no yellowing or significantly less yellowing compared to a control sample that has been subjected to UV exposure.

[0035] In addition, different phosphors can be mixed into the ink composition so as to emit white or off-white visible light, thereby creating a brighter appearance of the polymeric material. The concept of generating white light by mixing phosphors that emit at different wavelengths is similar to that observed in the generation of white light using LEDs, as shown in FIG. 6. For example, a common white light source can be achieved by mixing red light, green light, and blue light in appropriate intensity ratios. Alternatively, a white light source can be achieved by mixing yellow light and blue light in appropriate intensity ratios. Embodiments are provided herein in which phosphors are selected and incorporated into the ink composition such that different colors of light are emitted and then combined to produce white light.

[0036] As used herein, "white light" refers to a combination of all wavelengths of electromagnetic radiation in the visible range of the spectrum, with each wavelength present in equal amounts relative to the other wavelengths. "Off-white" light refers to a combination of wavelengths within the visible range of electromagnetic radiation that is, for example, close to white light but not present in equal amounts.

[0037] As used herein, "photooxidation" refers to the degradation of the polymer surface due to the combined action of light and oxygen. Photooxidation causes the cleavage of polymer chains, resulting in an increase in the vulnerability of the material.

[0038] As used herein, the terms "inorganic phosphor dopant" and "phosphor" can be used interchangeably.

[0039] As used herein, an "ultraviolet curable" ink composition refers to an ink formulation that contains one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers and dries or cures upon exposure to ultraviolet light.

[0040] II. Ink Composition A. In some embodiments, the subject matter described herein relates to an ink composition (110) comprising one or more inorganic phosphor dopants (100), a solvent (111), and a binder (112).

[0041] In some embodiments of the above ink composition (110), one or more inorganic phosphor dopants (100) have a diameter of 0.5 μm or less so as to be compatible with a print head and pass through the print head, for example, when the ink composition (110) is printed on the surface (101a) of a substrate (101). In some other embodiments, one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in some other embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm to 0.5 μm, about 0.05 μm to 0.45 μm, about 0.10 μm to 0.3 μm, about 0.2 μm to 0.5 μm, about 0.4 μm to 0.5 μm, about 0.01 μm to 0.2 μm, about 0.2 μm to 0.3 μm, or about 0.35 μm to 0.45 μm. In some embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.30 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, and 0.50 μm. The size of the inorganic phosphor dopant (100) can be measured, for example, using dynamic light scattering (DLS) according to ASTM E3247-20 ("Standard Test Method for Measuring the Size of Nanoparticles in Aqueous Media Using Dynamic Light Scattering").

[0042] In some embodiments of the ink composition (110), one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 1 to 75 wt% to obtain the correct optical density depending on the use of the ink composition (110). In some other embodiments including but not limited to the ink composition (110) formulated as a graphic inkjet ink composition, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 1 to 50 wt%, about 1 to 25 wt%, about 1 to 15 wt%, about 1 to 10 wt%, about 1 to 5 wt%, about 1 to 3 wt%, or about 1 to 2 wt%. In some other embodiments including but not limited to the ink composition (110) formulated as a non-graphic ink composition, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 50 to 75 wt%, about 55 to 70 wt%, or about 60 to 65 wt%. In some embodiments, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in amounts of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, and about 75 wt%.

[0043] In some embodiments of the ink composition (110), one or more inorganic phosphor dopants (100) can emit photons (105) having a wavelength of light between about 200 nm and 280 nm, between about 200 nm and 270 nm, between about 200 nm and 250 nm, between about 225 nm and 250 nm, between about 200 nm and 225 nm, between about 200 nm and 275 nm, or between about 225 nm and 275 nm upon exposure to an ultraviolet light source (104).

[0044] In some embodiments of the ink composition (110), each of one or more inorganic phosphor dopants (100) is independently Pr 3+ , Ce3+ , Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , or a metal oxide (106) and a metal fluoride (108) containing a rare earth ion (107) selected from the group consisting of a mixture thereof. In some embodiments of the ink composition (110), the rare earth ion (107) is Pr +3 . In some embodiments of the ink composition (110), the metal oxide (106) is in each case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some embodiments, the silicate is selected from the group consisting of melilite, cyclic silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7, (Ca, Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20 , and Y2SiO5. Non-limiting examples of borates include YBO3 and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M = Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 , NaGdGeO4, Cd3Al2Ge3O 12 , CaTiO3, Ca 0.8 Zn 0.2 TiO3, and Ca2Zn4Ti 15 O 36 . Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O 4、CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 is included. In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is Ca2Al2SiO7 doped with 3+ Pr.

[0045] In some embodiments of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors. In some embodiments, the one or more inorganic phosphor dopants (100) is Cs2NaYF6 doped with 3+ Pr (Cs2NaYF6:Pr 3+ ). In one embodiment, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 0.3% to about 10%. In other embodiments, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 1% to 5%, from 1.5% to 4.5%, from 2.5% to 5%, from 2% to 7%, from 3% to 8%, or from 4% to 9% and substitutes.

[0046] In some embodiments of the above ink composition (110), the solvent (111) is selected from, but not limited to, alcohols (e.g., particularly methanol, ethanol, propanol, isopropyl alcohol, butanol, polyols, ethylene glycol, glycerin, and PEG), ketones and ketone alcohols (e.g., particularly acetone and diacetone alcohol), ethers (e.g., particularly tetrahydrofuran, dioxane, and alkyl ethers), ethers of polyhydric alcohols (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, di(ethylene glycol) monomethyl ether), nitrogen-containing solvents (e.g., particularly 2-pyrrolidone and N-methyl-2-pyrrolidone), sulfur-containing solvents (e.g., particularly 2,2′-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone, sulfolane), and their sugars and derivatives (e.g., particularly glucose, oxyethylene adducts of glycerin, and oxyethylene adducts of diglycerin). In some embodiments of the above ink composition (110), the solvent (111) is selected from the group consisting of water, methanol, ethanol, propanol, isopropyl alcohol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. In some embodiments, the solvent (111) is water. In some other embodiments, the solvent (111) consists of water and one or more co-solvents that can be water-soluble, water-miscible, or a combination thereof. Such a solvent (111) can be used to affect the fluidity of the ink composition (110). For example, in some embodiments, if the flow of the ink composition (110) is insufficient otherwise, the use of the solvent (111) is necessary to increase the flow of the ink composition (110).

[0047] In some embodiments of the ink composition (110), the binder (112) is a water-soluble or alcohol-soluble binder. In some embodiments, the binder (112) is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane, and polyvinyl alcohol. In some embodiments of the above method, the binder (112) cures by evaporation. In some embodiments, the binder (112) has a molecular weight of less than 100,000, often less than 50,000. In some embodiments, the binder (112) includes one or more of vinyl chloride / vinyl acetate copolymer, acrylic, and polyketone.

[0048] In some embodiments of the ink composition (110), the ink composition (110) has a viscosity of from about 2 mPa·s to about 30 mPa·s to impart sufficient flow to the ink composition (110). In some embodiments, the ink composition (110) has a viscosity of from about 2 mPa·s to about 25 mPa·s, from about 5 mPa·s to about 15 mPa·s, from about 10 mPa·s to about 30 mPa·s, from about 10 mPa·s to about 20 mPa·s, from about 5 mPa·s to about 25 mPa·s, from about 7 mPa·s to about 23 mPa·s, from about 6 mPa·s to about 27 mPa·s, from about 4 mPa·s to about 18 mPa·s, from about 12 mPa·s to about 24 mPa·s, or from about 18 mPa·s to about 28 mPa·s.

[0049] In some embodiments of the ink composition (110), the ink composition (110) is formulated as a paint. In some other embodiments of the ink composition (110), the ink composition (110) is formulated as a dip coating or padding. In still some other embodiments of the ink composition (110), the ink composition (110) is formulated as an aerosol spray. In still some other embodiments of the ink composition (110), the ink composition (110) is formulated for rotary screen printing.

[0050] The preferred amounts and relative ratios of the components of the ink composition (110) (inorganic phosphor dopant (100), solvent (111), and binder (112)) will vary widely based on the intended use of the ink composition (110). For example, in the rotary screen printing method, the manufacturer requires that the ink composition (110) be non-Newtonian and exhibit a high viscosity, an attribute that is not compatible with an inkjet printer.

[0051] B. In some embodiments, the subject matter described herein relates to an ultraviolet curable ink composition (113) comprising one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115).

[0052] The ultraviolet curable ink composition (113) of the present application is compatible with a wide range of substrates (101) and does not solidify until the ultraviolet curable ink composition (113) reacts with an appropriate amount or wavelength of ultraviolet light, facilitating the maintenance of the print head. The ultraviolet curable ink composition (113) of the present application has good durability and is environmentally beneficial because the VOC is almost zero. In addition, the ultraviolet curable ink composition (113) of the present application can control the thickness of the applied film layer (i.e., can be stacked by an additive printing technique).

[0053] In some embodiments of the above ultraviolet curable ink composition (113), one or more inorganic phosphor dopants (100) have a diameter of 0.5 μm or less so as to be compatible with a printer head and pass through the printer head, for example, when the ultraviolet curable ink composition (113) is printed on the surface (101a) of a substrate (101). In some other embodiments, one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in some other embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm to 0.5 μm, about 0.05 μm to 0.45 μm, about 0.10 μm to 0.3 μm, about 0.2 μm to 0.5 μm, about 0.4 μm to 0.5 μm, about 0.01 μm to 0.2 μm, about 0.2 μm to 0.3 μm, or about 0.35 μm to 0.45 μm. In some embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.30 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, and 0.50 μm. The size of the inorganic phosphor dopant (100) can be measured, for example, using dynamic light scattering (DLS) according to ASTM E3247-20 ("Standard Test Method for Measuring the Size of Nanoparticles in Aqueous Media Using Dynamic Light Scattering").

[0054] In some embodiments of the above ultraviolet curable ink composition (113), one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 1 to 75 wt% in order to obtain the correct optical density depending on the use of the ultraviolet curable ink composition (113). In some other embodiments including but not limited to the ultraviolet curable ink composition (113) formulated as a graphic inkjet ink composition, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 1 to 50 wt%, about 1 to 25 wt%, about 1 to 15 wt%, about 1 to 10 wt%, about 1 to 5 wt%, about 1 to 3 wt%, or about 1 to 2 wt%. In some other embodiments including but not limited to the ultraviolet curable ink composition (113) formulated as a non-graphic ink composition, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 50 to 75 wt%, about 55 to 70 wt%, or about 60 to 65 wt%. In some embodiments, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in amounts of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, and about 75 wt%.

[0055] In some embodiments of the above ultraviolet curable ink composition (113), one or more inorganic phosphor dopants (100) can emit photons (105) having a wavelength of light between about 200 nm and 280 nm, about 200 nm and 270 nm, about 200 nm and 250 nm, about 225 nm and 250 nm, about 200 nm and 225 nm, about 200 nm and 275 nm, or about 225 nm and 275 nm upon exposure to an ultraviolet light source (104).

[0056] In some embodiments of the above ultraviolet curable ink composition (113), one or more inorganic phosphor dopants (100) each independently comprise a metal oxide (106) and a metal fluoride (108) containing a rare earth ion (107) selected from the group consisting of Pr 3+ , Ce 3+ , Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , or a mixture thereof. In some embodiments of the ultraviolet curable ink composition (113), the rare earth ion (107) is Pr +3 . In some embodiments of the ultraviolet curable ink composition (113), the metal oxide (106) is in each case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some embodiments, the silicate is selected from the group consisting of melilite, cyclo-silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7, (Ca,Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20 , and Y2SiO5. Non-limiting examples of borates include YBO3 and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M = Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 , NaGdGeO4, Cd3Al2Ge3O 12 , CaTiO3, Ca 0.8 Zn 0.2 TiO3, and Ca2Zn4Ti 15 O36 It includes. Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O 4、 CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 is included. In some embodiments of one or more inorganic phosphor dopants (100), the metal oxide (106) is Ca2Al2SiO7 doped with 3+ Pr.

[0057] In some embodiments of one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors. In some embodiments, one or more inorganic phosphor dopants (100) are Cs2NaYF6 doped with 3+ Pr (Cs2NaYF6:Pr 3+ ). In one embodiment, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 0.3% to about 10%. In other embodiments, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 1% to 5%, from 1.5% to 4.5%, from 2.5% to 5%, from 2% to 7%, from 3% to 8%, or from 4% to 9% and substitutes.

[0058] In some embodiments of the above ultraviolet curable ink composition (113), each of one or more photoinitiators (114) is independently selected from the group consisting of 4,4′-bis(dimethylamino)benzophenone, thioxanthen-9-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,4-dinitro-1-naphthol, and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO).

[0059] In some embodiments of the above ultraviolet curable ink composition (113), one or more monomers (115) are each independently an acrylate monomer. In some embodiments of the ultraviolet curable ink composition (113), one or more monomers (115) are each independently 1,6 - hexanediol diacrylate (HDDA), poly(ethylene glycol) diacrylate (PEGDA), 1,3 - butylene glycol diacrylate, di - trimethylolpropane tetraacrylate, hexanediol diacrylate, ethoxy(3)cyclohexanol, and / or dimethanol diacrylate. Such acrylate monomers (115) can be used as binders (112) to improve one or more properties of the ultraviolet curable ink composition (113), such as pigment dispersibility, adhesiveness, chemical resistance, mechanical resistance, and ultraviolet resistance. For example, in some embodiments of the above method where it is desired that there is no or little odor, suitable acrylate monomers (115) can include tridecyl acrylate (8 mPas at 25 °C), caprolactone acrylate (75 mPas at 25 °C), ethoxylated(4)phenol acrylate (35 mPas at 25 °C), ethoxylated(4)nonylphenol acrylate (90 mPas at 25 °C), and / or cyclic trimethylolpropane formal acrylate (12 mPas at 25 °C).

[0060] In some embodiments of the above method where medium to high flexibility is desired (e.g., to apply a printed film to a contoured surface (101a) and resist cracking), suitable acrylate monomers (115) can include ethoxylated(4)phenol acrylate (35 mPas at 25 °C), polyethylene glycol(200) diacrylate (25 mPas at 25 °C) (very flexible), propoxylated(3)trimethylolpropane triacrylate (100 mPas at 25 °C), and / or ethoxylated(3)trimethylolpropane triacrylate (70 mPas at 25 °C) (ethoxylated up to 15(EO); more flexible, less odor).

[0061] In other embodiments of the above method where medium hardness is desired (e.g., to resist wear, scratches, and gouges), suitable acrylate monomer (115) may include tricyclodecane dimethanol diacrylate (120 mPas at 25 °C).

[0062] In other embodiments of the above method where medium toughness is desired (e.g., to resist breakage by impact), suitable acrylate monomer (115) may include isobornyl acrylate (10 mPas at 25 °C) (very tough), isophorone acrylate (6 mPas at 25 °C) (high impact strength), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25 °C), dioxane glycol diacrylate (250 mPas at 25 °C), ethoxylated bisphenol A diacrylate (1500 mPas at 25 °C) (very tough), and / or trimethylolpropane triacrylate (110 mPas at 25 °C).

[0063] In other embodiments of the above method where good adhesion is desired (e.g., to resist removal from various substrates), suitable acrylate monomer (115) may include diethylene glycol butyl ether acrylate (5 mPas at 25 °C), 2(2-ethoxyethoxy)ethyl acrylate (5 mPas at 25 °C), tetrahydrofurfuryl acrylate (5 mPas at 25 °C), isobornyl acrylate (10 mPas at 25 °C), cyclic trimethylolpropane formal acrylate (12 mPas at 25 °C), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25 °C), hexanediol diacrylate (7 mPas at 25 °C), tricyclodecane dimethanol diacrylate (120 mPas at 25 °C) extremely versatile: dioxane glycol diacrylate (250 mPas at 25 °C), and / or propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25 °C).

[0064] Good wettability is desired (e.g., to produce good printed film quality / uniformity). In some other embodiments of the above method, suitable acrylate monomers (115) may include isodecyl acrylate (10 mPas at 25 °C), octyl / decyl acrylate (10 mPas at 25 °C), propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25 °C) (excellent pigment wettability), and / or propoxylated (3) trimethylolpropane triacrylate (100 mPas at 25 °C).

[0065] In some other embodiments of the above method, the acrylate monomer (115) may be selected to impart a sufficiently low viscosity (e.g., to be injectable from a piezo head; 25 - 45 °C, heuristic 25 cP) and / or chemical resistance (e.g., to withstand degradation by exposure to any number of commercially available surface cleaners and disinfectants so that it can be used by airline operators).

[0066] In some embodiments of the above ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) further comprises one or more additives for reducing surface tension and / or improving wettability of the substrate. By reducing the surface tension, properties such as droplet formation and substrate wettability can be improved. In some embodiments of the above ultraviolet curable ink composition (113), the one or more additives are selected from the group consisting of alkoxylated, silicone, silicone - acrylated surfactants, and fluorocarbons.

[0067] In some embodiments of the ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) has a viscosity of about 5 mPa·s to about 35 mPa·s. In some embodiments, the ultraviolet curable ink composition (113) has a viscosity of about 5 mPa·s to about 25 mPa·s, about 5 mPa·s to about 20 mPa·s, about 5 mPa·s to about 15 mPa·s, about 10 mPa·s to about 30 mPa·s, about 7 mPa·s to about 24 mPa·s, about 10 mPa·s to about 27 mPa·s, about 12 mPa·s to about 22 mPa·s, about 15 mPa·s to about 30 mPa·s, about 8 mPa·s to about 28 mPa·s, about 9 mPa·s to about 23 mPa·s, about 14 mPa·s to about 25 mPa·s, or about 13 mPa·s to about 26 mPa·s.

[0068] In some embodiments of the ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) is formulated as a paint. In some other embodiments of the ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) is formulated as a dip coating or padding. In still some other embodiments of the ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) is formulated as an aerosol spray. In yet some other embodiments of the ultraviolet curable ink composition (113), the ultraviolet curable ink composition (113) is formulated for rotary screen printing.

[0069] The preferred amounts and relative ratios of the components of the ultraviolet curable ink composition (113) (one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115)) vary widely depending on the intended use of the ultraviolet curable ink composition (113). For example, in the rotary screen printing method, the manufacturer requires that the ultraviolet curable ink composition (113) be non-Newtonian and exhibit a high viscosity, an attribute that may be incompatible with an inkjet printer.

[0070] III. Method for Preparing Ink Composition Methods for preparing inorganic phosphor dopants (100) are known in the art. See, for example, Broxtermann et al. ECS Journal of Solid State Science and Technology, 6(4) R47-R52 (2017); and Poelman et al. Journal of Applied Physics 128, 240903 (2020). In an example, a certain amount of host material and rare earth oxide of metal oxide (106) are weighed such that rare earth ions (107) are substituted or doped into the metal oxide (106) lattice. The amount of rare earth ions (107) added can be determined by calculating the stoichiometry presented for the material and then weighing out the appropriate amount of starting materials using dimensional analysis. The metal oxide (106) powder is thoroughly ground using a mortar and pestle to maximize contact between the particles in the mixture. After placing it in a suitable crucible (often alumina), the mixture is heated in a tube furnace or muffle furnace to a temperature sufficient to induce a solid reaction but below the melting point of the final compound. From a temperature about 200 - 300 °C lower than this melting temperature, the particle size of the final compound increases significantly. This heating process is called sintering and generally results in a very dense and strongly agglomerated material. This material cannot be applied directly as a phosphor. Thus, in many cases, it is necessary to grind it manually or using a ball mill after synthesis.

[0071] Ball milling is a mechanical method of reducing particle size by mechanical impact and friction. Typically, the powder is placed in a milling jar together with a number of hard milling balls (often Al2O3 or ZrO2) and a solvent such that a slurry is obtained. Then, the milling jar is moved so as to maximize friction. Similar to the case of manual grinding using a mortar and pestle, the effect of this process depends greatly on the size and hardness of the starting materials.

[0072] In the case of the above solid synthesis, the atmosphere used for heating can vary depending on the host material. In the case of oxides, air can usually be applied. However, some dopants, especially europium, are oxidized within the oxygen lattice while being heated in oxygen, leading to the formation of a completely oxidized Eu 3+ dopant. If Eu 2+ is the preferred valence state of this dopant, additional heat treatment may be required in a reducing atmosphere such as helium or argon.

[0073] Other methods for preparing the inorganic phosphor dopant (100) include sol-gel synthesis, colloidal synthesis, and coprecipitation. In the sol-gel method, for example, powders are weighed out, dissolved in a concentrated acid such as HNO3 (e.g., 70% w / w), and then diluted with deionized water. This solution is then cooled to room temperature and added dropwise to a low-temperature saturated aqueous solution of another acid such as oxalic acid. The solid material is then precipitated and then washed with deionized water and other polar solvents (such as acetone, acetonitrile, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), isopropanol, or methanol). The solid material is then calcined at a temperature of about 1000 °C to 1200 °C for several hours, followed by intermittent grinding and sintering. In some embodiments, after weighing and mixing, the metal oxide (106) host powder and the rare earth oxide powder are directly placed in a furnace at 1000 - 1100 °C for 2 - 48 hours.

[0074] As shown in FIGS. 1 and 2, for example, when one or more inorganic phosphor dopants (100) are prepared, they are used to formulate an ink composition (110) and / or an ultraviolet curable ink composition (113) as described below.

[0075] A. In some embodiments, the subject matter described herein relates to a method of making an ink composition (110) comprising one or more inorganic phosphor dopants (100), a solvent (111), and a binder (112), the method comprising, as further shown in FIG. 1, preparing one or more inorganic phosphor dopants (100) in step 150 and contacting a solvent (111) with one or more inorganic phosphor dopants (100) and a binder (112) in step 155 to prepare the ink composition (110).

[0076] In some embodiments of the above method, one or more inorganic phosphor dopants (100) have a diameter of 0.5 μm or less and are adapted to a printhead and capable of passing through the printhead, for example, such that an ink composition (110) is printed on a surface (101a) of a substrate (101). In some other embodiments, one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in some other embodiments of the above method, one or more inorganic phosphor dopants (100) have a diameter of from about 0.01 μm to 0.5 μm, from about 0.05 μm to 0.45 μm, from about 0.10 μm to 0.3 μm, from about 0.2 μm to 0.5 μm, from about 0.4 μm to 0.5 μm, from about 0.01 μm to 0.2 μm, from about 0.2 μm to 0.3 μm, or from about 0.35 μm to 0.45 μm. In some embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.30 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, and 0.50 μm. The size of the inorganic phosphor dopant (100) can be measured, for example, using dynamic light scattering (DLS) according to ASTM E3247-20 ("Standard Test Method for Measuring the Size of Nanoparticles in Aqueous Media Using Dynamic Light Scattering").

[0077] In some embodiments of the above method, one or more inorganic phosphor dopants (100) can emit photons (105) having a wavelength of light between about 200 nm and 280 nm, between about 200 nm and 270 nm, between about 200 nm and 250 nm, between about 225 nm and 250 nm, between about 200 nm and 225 nm, between about 200 nm and 275 nm, or between about 225 nm and 275 nm upon exposure to an ultraviolet light source (104).

[0078] In some embodiments of the above method, one or more inorganic phosphor dopants (100) each independently contain a rare earth ion (107) selected from the group consisting of Pr 3+ , Ce 3+ , Eu 3+ Eu 2+ Gd 3+ Tb 3+ and Dy 3+ or a mixture thereof, and is selected from the group consisting of a metal oxide (106) and a metal fluoride (108). In some embodiments of the above method, the rare earth ion (107) is Pr +3 . In some embodiments of the above method, the metal oxide (106) in each case is selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some embodiments, the silicate is selected from the group consisting of melilite, cyclo-silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7, (Ca,Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20and Y2SiO5 are included. Non-limiting examples of borates include YBO3 and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M = Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 , NaGdGeO4, Cd3Al2Ge3O 12 , CaTiO3, Ca 0.8 Zn 0.2 TiO3, and Ca2Zn4Ti 15 O 36 are included. Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O 4、 CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 are included. In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is Ca2Al2SiO7 doped with Pr 3+ .

[0079] In some embodiments of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors. In some embodiments, the one or more inorganic phosphor dopants (100) are Cs2NaYF6 doped with Pr 3+ (Cs2NaYF6:Pr 3+ ). In one embodiment, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 0.3% to about 10%. In other embodiments, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 1% to 5%, from 1.5% to 4.5%, from 2.5% to 5%, from 2% to 7%, from 3% to 8%, or from 4% to 9% Replace.

[0080] In some embodiments of the above method, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 1 to 75 wt% to obtain the correct optical density depending on the use of the ink composition (110). In some other embodiments including, but not limited to, the ink composition (110) formulated as a graphic inkjet ink composition, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 1 to 50 wt%, about 1 to 25 wt%, about 1 to 15 wt%, about 1 to 10 wt%, about 1 to 5 wt%, about 1 to 3 wt%, or about 1 to 2 wt%. In some other embodiments including, but not limited to, the ink composition (110) formulated as a non-graphic ink composition, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in an amount of about 50 to 75 wt%, about 55 to 70 wt%, or about 60 to 65 wt%. In some embodiments, one or more inorganic phosphor dopants (100) are present in the ink composition (110) in amounts of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, and about 75 wt%.

[0081] Several suitable solvents (111) are described, for example, in S. Magdassi, Chemistry of Inkjet Inks (2009). In some embodiments of the above method, the solvent (111) is alcohol (e.g., in particular methanol, ethanol, propanol, isopropyl alcohol, butanol, polyol, ethylene glycol, glycerin, and PEG), ketone and ketone alcohol (e.g., in particular acetone and diacetone alcohol, and cyclohexanone and isophorone having a higher boiling point), ether (e.g., in particular tetrahydrofuran, dioxane, and alkyl ether), ether of polyhydric alcohol (e.g., ethylene glycol ether, propylene glycol ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, di(ethylene glycol) monomethyl ether), nitrogen-containing solvent (e.g., in particular 2-pyrrolidone, and N-methyl-2-pyrrolidone), ester of these ethers, sulfur-containing solvent (e.g., in particular 2,2′-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone, and sulfolane), alkyl lactate, and sugar and its derivatives (e.g., in particular glucose, oxyethylene adduct of glycerin, and oxyethylene adduct of diglycerin), but not limited thereto. In some embodiments of the ink composition (110) above, the solvent (111) is selected from the group consisting of water, methanol, ethanol, propanol, isopropyl alcohol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. In some embodiments, the solvent (111) is water. In some other embodiments, the solvent (111) consists of water and one or more co-solvents that can be water-soluble, water-miscible, or a combination thereof. For the ink composition (110) formulated for use in inkjet printing, a solvent (111) or blend of solvents (111) is desired such that the ink composition (110) dries fast enough after being printed on the substrate (101), but does not dry so fast that the ink dries in the printhead nozzles.According to S. Magdassi, the solvent (111) generally has an evaporation rate in the medium (0.8 - 3) or slow (<0.3 on a scale where n-butyl acetate = 1) range.

[0082] In some embodiments, one or more solvents (111) are preferably present in the ink composition (110) in an amount of about 1 to 99 weight percent. When using a mixture of solvents (111), the mixture can contain any suitable proportion of solvents (111). Such solvents (111) can be used to affect the viscosity, diffusion, and evaporation rate of the ink composition (110). For example, in some embodiments, when the flow of the ink composition (110) is otherwise insufficient, it is necessary to use a solvent (111) to reduce the viscosity of the ink composition (110). In some other embodiments, including but not limited to ink compositions (110) formulated for inkjet printing, one or more solvents (111) are present in the ink composition (110) in an amount of about 50 to 99 weight percent, 50 to 90 weight percent, about 50 to 85 weight percent, or about 60 to about 85 weight percent. In some other embodiments, including but not limited to ink compositions (110) formulated as non-graphic ink compositions, one or more solvents (111) are present in the ink composition (110) in an amount of about 25 to 50 weight percent, about 30 to 45 weight percent, or about 35 to 40 weight percent. In some embodiments, one or more solvents (111) are present in the ink composition (110) in amounts of about 10 weight percent, about 20 weight percent, about 25 weight percent, about 30 weight percent, about 35 weight percent, about 40 weight percent, about 45 weight percent, about 50 weight percent, about 55 weight percent, about 60 weight percent, about 65 weight percent, about 70 weight percent, about 75 weight percent, about 80 weight percent, about 85 weight percent, about 90 weight percent, about 95 weight percent, about 98 weight percent, and about 99 weight percent. In some embodiments of the above method, the ink composition (110) has a viscosity of about 2 mPa·s to about 30 mPa·s. In some embodiments, the ink composition (110) has a viscosity of about 2 mPa·s to about 25 mPa·s, about 5 mPa·s to about 15 mPa·s, about 10 mPa·s to about 30 mPa·s, about 10 mPa·s to about 20 mPa·s, about 5 mPa·s to about 25 mPa·s, about 7 mPa·s to about 23 mPa·s, about 6 mPa·s to about 27 mPa·s, about 4 mPa·s to about 18 mPa·s, about 12 mPa·s to about 24 mPa·s, or about 18 mPa·s to about 28 mPa·s.

[0083] In some embodiments of the above method, the binder (112) is a water-soluble or alcohol-soluble binder. In some embodiments, the binder (112) is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane, and polyvinyl alcohol. In some other embodiments, acrylates with various functionalities and shares are used to form the binder (112). In some embodiments of the above ink composition (110), the binder (112) is an important component that affects the film properties of the application, such as the graphics and protective varnish of aircraft wallpapers. In some embodiments of the above method, the binder (112) cures by evaporation. In some embodiments, after printing, coating, or otherwise applying the ink composition (110) to the surface (101a) and curing it, the binder (112) serves to hold and bind the pigment and / or inorganic phosphor dopant (100) to the surface (101a).

[0084] In some embodiments, one or more binders (112) are preferably present in the ink composition (110) in an amount of about 1 to 25% by weight. When using a mixture of binders (112), the mixture can contain any suitable proportion of binders (112). In some embodiments, one or more binders (112) are present in the ink composition (110) in an amount of about 5 to 25% by weight, about 10 to 20% by weight, or about 15 to 18% by weight. In some embodiments, one or more binders (112) are present in the ink composition (110) in amounts of about 1% by weight, 3% by weight, 5% by weight, 10% by weight, 15% by weight, 18% by weight, 20% by weight, and 25% by weight.

[0085] In some embodiments, the solvent (111) is contacted with one or more prepared inorganic phosphor dopants (100) and the binder (112). In some embodiments of the above method, one or more inorganic phosphor dopants (100) are in powder form and are combined with the solvent (111) and the binder (112). Then, one or more inorganic phosphor dopants (100), the solvent (111), and the binder (112) are mixed to form the ink composition (110).

[0086] B. In some embodiments, the subject matter described herein relates to a method of making an ultraviolet curable ink composition (113) comprising one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115), the method comprising, as further shown in FIG. 2, at step 250, preparing one or more inorganic phosphor dopants (100), and at step 255, contacting one or more inorganic phosphor dopants (100) with one or more photoinitiators (114) and one or more monomers (115) to prepare an ultraviolet curable ink composition (113).

[0087] In some embodiments of the above method, one or more inorganic phosphor dopants (100) have a diameter of 0.5 μm or less so that the ultraviolet curable ink composition (113) can be compatible with and pass through a printer head, for example, when printed on the surface (101a) of a substrate (101). In some other embodiments, one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in some other embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm to 0.5 μm, about 0.05 μm to 0.45 μm, about 0.10 μm to 0.3 μm, about 0.2 μm to 0.5 μm, about 0.4 μm to 0.5 μm, about 0.01 μm to 0.2 μm, about 0.2 μm to 0.3 μm, or about 0.35 μm to 0.45 μm. In some embodiments, one or more inorganic phosphor dopants (100) have a diameter of about 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.30 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, and 0.50 μm. The size of the inorganic phosphor dopant (100) can be measured, for example, using dynamic light scattering (DLS) according to ASTM E3247-20 ("Standard Test Method for Measuring the Size of Nanoparticles in Aqueous Media Using Dynamic Light Scattering").

[0088] In some embodiments of the above method, one or more inorganic phosphor dopants (100) can emit photons (105) having a wavelength of light between about 200 nm and 280 nm, between about 200 nm and 270 nm, between about 200 nm and 250 nm, between about 225 nm and 250 nm, between about 200 nm and 225 nm, between about 200 nm and 275 nm, or between about 225 nm and 275 nm upon exposure to an ultraviolet light source (104).

[0089] In some embodiments of the above method, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 1 to 75 wt% in order to obtain the correct optical density depending on the use of the ultraviolet curable ink composition (113). In some other embodiments including but not limited to the ultraviolet curable ink composition (113) formulated as a graphic inkjet ink composition, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 1 to 50 wt%, about 1 to 25 wt%, about 1 to 15 wt%, about 1 to 10 wt%, about 1 to 5 wt%, about 1 to 3 wt%, or about 1 to 2 wt%. In some other embodiments including but not limited to the ultraviolet curable ink composition (113) formulated as a non-graphic ink composition, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in an amount of about 50 to 75 wt%, about 55 to 70 wt%, or about 60 to 65 wt%. In some embodiments, one or more inorganic phosphor dopants (100) are present in the ultraviolet curable ink composition (113) in amounts of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, and about 75 wt%.

[0090] Some suitable photoinitiators (114) are described, for example, in S. Magdassi, Chemistry of Inkjet Inks 10: Raw Materials for UV Curable Inks (2009) and W. Zapka, Handbook of Industrial Inkjet Printing: A Full System Approach, Section 4.2 Photoinitiators. In some embodiments of the above method, one or more photoinitiators (114) are each independently 4,4′-bis(dimethylamino)benzophenone, thioxanthen-9-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,4-dinitro-1-naphthol, monoacylphosphine oxide (Lucerin TPO), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), azobisisobutyronitrile (AIBN), benzyldimethylketal (BDK, Irgacure 651), 2-hydroxymethyl-1-phenylpropane (Darocure 1173), hydroxycyclohexylphenylketone (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, Esacure KIP150, monoacylphosphine oxide (MAPO) and bisacylphosphine oxide photoinitiator (BAPO).

[0091] In some embodiments, one or more photoinitiators (114) are preferably present in the ultraviolet curable ink composition (113) in an amount of about 0.1 to 15 wt% to generate sufficient unpaired electrons or radicals to assist in the polymerization of the monomer (115). When a mixture of photoinitiators (114) is used, the mixture can contain any suitable ratio of photoinitiators (114).

[0092] In some embodiments of the above method, one or more monomers (115) are each independently an acrylate monomer. In some embodiments of the above method, one or more monomers (115) are each independently 1,6 - hexanediol diacrylate (HDDA), poly(ethylene glycol) diacrylate (PEGDA), 1,3 - butylene glycol diacrylate, di - trimethylolpropane tetraacrylate, hexanediol diacrylate, ethoxy(3) cyclohexanol, and / or dimethanol diacrylate. Such acrylate monomers (115) can be used as binders (112) to improve one or more properties of the ultraviolet - curable ink composition (113), such as pigment dispersibility, adhesiveness, chemical resistance, mechanical resistance, and ultraviolet resistance. For example, in some embodiments of the above method where it is desired that there is no or little odor, suitable acrylate monomers (115) can include tridecyl acrylate (8 mPas at 25 °C), caprolactone acrylate (75 mPas at 25 °C), ethoxylated(4) phenol acrylate (35 mPas at 25 °C), ethoxylated(4) nonylphenol acrylate (90 mPas at 25 °C), and / or cyclic trimethylolpropane formal acrylate (12 mPas at 25 °C).

[0093] In some embodiments of the above method where medium to high flexibility is desired (e.g., for applying a printed film to a contoured surface and resisting cracking), suitable acrylate monomers (115) can include ethoxylated(4) phenol acrylate (35 mPas at 25 °C), polyethylene glycol(200) diacrylate (25 mPas at 25 °C) (which is very flexible), propoxylated(3) trimethylolpropane triacrylate (100 mPas at 25 °C), and / or ethoxylated(3) trimethylolpropane triacrylate (70 mPas at 25 °C) (more ethoxylated up to 15(EO); higher flexibility, less odor).

[0094] In other embodiments of the above method where a medium level of hardness is desired (e.g., to resist wear, scratches, and gouges), suitable acrylate monomer (115) may include tricyclodecane dimethanol diacrylate (120 mPas at 25 °C).

[0095] In other embodiments of the above method where a medium level of toughness is desired (e.g., to resist breakage by impact), suitable acrylate monomer (115) may include isobornyl acrylate (10 mPas at 25 °C) (very tough), isophorone acrylate (6 mPas at 25 °C) (high impact strength), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25 °C), dioxane glycol diacrylate (250 mPas at 25 °C), ethoxylated bisphenol A diacrylate (1500 mPas at 25 °C) (very tough), and / or trimethylolpropane triacrylate (110 mPas at 25 °C).

[0096] In other embodiments of the above method where good adhesion is desired (e.g., to resist removal from various substrates (101)), suitable acrylate monomer (115) may include diethylene glycol butyl ether acrylate (5 mPas at 25 °C), 2(2-ethoxyethoxy)ethyl acrylate (5 mPas at 25 °C), tetrahydrofurfuryl acrylate (5 mPas at 25 °C), isobornyl acrylate (10 mPas at 25 °C), cyclic trimethylolpropane formal acrylate (12 mPas at 25 °C), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25 °C), hexanediol diacrylate (7 mPas at 25 °C), tricyclodecane dimethanol diacrylate (120 mPas at 25 °C) (very versatile), dioxane glycol diacrylate (250 mPas at 25 °C), and / or propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25 °C).

[0097] In some other embodiments of the above method where good wettability is desired (e.g., to produce good printed film quality / uniformity), suitable acrylate monomers (115) may include isodecyl acrylate (10 mPas at 25 °C), octyl / decyl acrylate (10 mPas at 25 °C), propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25 °C) (excellent pigment wettability), and / or propoxylated (3) trimethylolpropane triacrylate (100 mPas at 25 °C).

[0098] In some other embodiments of the above method, the acrylate monomer (115) may be selected to impart a sufficiently low viscosity (e.g., to be jet - able from a piezoelectric print head having a viscosity between 6 cP and 25 cP at, for example, 25 - 60 °C, depending on the specifications of the head manufacturer) and / or chemical resistance (e.g., to withstand degradation by exposure to any number of commercially available surface cleaners and disinfectants such that, for example, an airline operator could use it).

[0099] As will be apparent to those skilled in the art in light of the present disclosure, the functionality of the acrylate will affect the various ink properties of the ultraviolet - curable ink composition (113). For example, as described in W. Zapka, Handbook of Industrial Inkjet Printing: A Full System Approach, the effect on each of ink viscosity, reactivity, hardness, solvent resistance, and brittleness increases as the acrylate functionality increases from mono - to penta - acrylate. The effect on the flexibility of the ultraviolet - curable ink composition (113) decreases as the acrylate functionality increases from mono - to penta - acrylate, and the effect on the shrinkage of the ultraviolet - curable ink composition (113) is lowest with mono - acrylate functionality, highest with tri - acrylate functionality, and moderate with penta - acrylate functionality.

[0100] In some embodiments of the above method, the method further comprises contacting one or more additives with one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115). In some embodiments, the one or more additives are for reducing surface tension and / or improving the wettability of the substrate. By reducing the surface tension, properties such as droplet formation and substrate wettability can be improved. In some embodiments of the above ultraviolet curable ink composition (113), the one or more additives are selected from the group consisting of alkoxylated, silicone, silicone-acrylated surfactants, and fluorocarbons.

[0101] In some embodiments of the above method, the ultraviolet curable ink composition (113) has a viscosity of about 5 mPa·s to about 35 mPa·s. In some embodiments of the above method, the ultraviolet curable ink composition (113) has a viscosity of from about 5 mPa·s to about 25 mPa·s, from about 5 mPa·s to about 20 mPa·s, from about 5 mPa·s to about 15 mPa·s, from about 10 mPa·s to about 30 mPa·s, from about 7 mPa·s to about 24 mPa·s, from about 10 mPa·s to about 27 mPa·s, from about 12 mPa·s to about 22 mPa·s, from about 15 mPa·s to about 30 mPa·s, from about 8 mPa·s to about 28 mPa·s, from about 9 mPa·s to about 23 mPa·s, from about 14 mPa·s to about 25 mPa·s, or from about 13 mPa·s to about 26 mPa·s.

[0102] In some embodiments of the above method, each of the one or more inorganic phosphor dopants (100) is independently selected from the group consisting of metal oxides (106) and metal fluorides (108) containing rare earth ions (107) selected from the group consisting of Pr 3+ , Ce 3+ , Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , or mixtures thereof. In some embodiments of the above method, the rare earth ion (107) is Pr +3It is. In some embodiments of the above method, the metal oxide (106) is in each case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some embodiments, the silicate is selected from the group consisting of melilite, cyclic silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7, (Ca, Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20 , and Y2SiO5 are included. Non-limiting examples of borates include YBO3 and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M = Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 、NaGdGeO4、Cd3Al2Ge3O 12 、CaTiO3、Ca 0.8 Zn 0.2 TiO3, and Ca2Zn4Ti 15 O 36 are included. Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O 4、 CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 are included. In some embodiments of one or more inorganic phosphor dopants (100), the metal oxide (106) is Ca2Al2SiO7 doped with Pr 3+ .

[0103] In some embodiments of one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors. In some embodiments, one or more inorganic phosphor dopants (100) are Pr 3+ doped Cs2NaYF6 (Cs2NaYF6:Pr 3+ ). In one embodiment, Pr 3+ replaces the yttrium ion sites in Cs2NaYF6 in an amount from about 0.3% to about 10%. In other embodiments, Pr 3+ replaces the yttrium ion sites in Cs2NaYF6 in an amount from about 1% to 5%, from 1.5% to 4.5%, from 2.5% to 5%, from 2% to 7%, from 3% to 8%, or from 4% to 9%.

[0104] In some embodiments, one or more prepared inorganic phosphor dopants (100) are contacted with one or more photoinitiators (114) and one or more monomers (115). In some embodiments of the above method, one or more inorganic phosphor dopants (100) are in powder form and are combined with one or more photoinitiators (114) and one or more monomers (115). In some embodiments, when other functional components such as coloring pigments are included in the ultraviolet curable ink composition (113), one or more inorganic phosphor dopants (100) can be mixed with other functional components before, simultaneously with, or after being combined with one or more photoinitiators (114) and one or more monomers (115).

[0105] In some embodiments, one or more additives are further incorporated into or otherwise combined with the inorganic phosphor dopant (100), one or more photoinitiators (114), and one or more monomers (115), and the additives are incorporated to improve one or more properties of the ultraviolet curable ink composition (113), such as shelf life, fluidity, and / or adhesion. For example, the surface tension of the print head selected for the method of printing and / or coating the surface (101a) must be carefully controlled because it can affect the wettability and surface tension of the ink in droplet formation during printing. In some embodiments, surfactants assist in controlling the surface tension and can be used in amounts ranging from about 0.1 to 2 weight percent. One or more inorganic phosphor dopants (100), one or more photoinitiators (114), one or more monomers (115), and any functional components and / or additives are then mixed to form the ultraviolet curable ink composition (113).

[0106] IV. Method of Surface Coating In some embodiments, the subject matter described herein relates to coating a surface (101a) with one or more of an ink composition (110) and / or an ultraviolet curable ink composition (113). As will be apparent to those skilled in the art in light of the present disclosure, such ink compositions (110) and / or ultraviolet curable ink compositions (113) can be employed in a wide variety of applications due to such disinfection properties and improved light stability. Also, as will be apparent to those skilled in the art in light of the present disclosure, the ink composition (110) and / or ultraviolet curable ink composition (113) can be used to coat the surface (101a) via a plurality of coating methods depending on industry and / or manufacturing requirements. In some embodiments, the ink composition (110) and / or ultraviolet curable ink composition (113) can be formulated to be applied by any number of coating techniques, such as dip coating, spray / atomization, roller coating, or brush painting. As will be apparent to those skilled in the art, since the inorganic phosphor dopant (100) is present in an amount less than the colorant loading of the pigment coating, a stable liquid that is compatible with coating tools (e.g., paint guns, inkjet print heads, etc.) can be obtained and then the formulation can be modified and / or rebalanced to support application such that it is applied via any one or more of such coating tools. For example, Table 1 presents an overview of exemplary coating methods, associated application ranges, how such coatings are implemented, and identification of substrate (101) materials and / or part types that can be coated by the associated methods. TIFF2025520502000002.tif226170

[0107] V. Methods for Disinfecting Surfaces In some embodiments, the subject matter described herein relates to a method for disinfecting a surface (101a), the surface (101a) being coated with an ink composition (110) comprising one or more inorganic phosphor dopants (100), a solvent (111), and a binder (112), the method comprising, as shown in FIG. 3, at step 350, exposing the surface (101a) coated with the ink composition (110) to an ultraviolet light source (104) to charge one or more inorganic phosphor dopants (100) in the ink composition (110), the exposing causing the one or more inorganic phosphor dopants (100) in the ink composition (110) to emit photons (105) having a wavelength of light in the UV-C range, the photons (105) irradiating the surface (101a), thereby disinfecting the surface (101a) at step 355. When the ink composition (110) dries and / or cures, the surface (101a) of the substrate (101) is coated with the inorganic phosphor dopant (100), any functional components (e.g., pigments for coloring), and the binder (112).

[0108] In other embodiments, the subject matter described herein relates to a method for disinfecting a surface (101a), the surface (101a) being coated with an ultraviolet curable ink composition (113) comprising one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115), the method comprising, as shown in FIG. 3, at step 350, exposing the surface (101a) coated with the ultraviolet curable ink composition (113) to an ultraviolet light source (104), the exposing causing the one or more inorganic phosphor dopants (100) in the ultraviolet curable ink composition (113) to emit photons (105) having a wavelength of light in the UV-C range, the photons (105) irradiating the surface (101a), thereby disinfecting the surface (101a) at step 355. When the ultraviolet curable ink composition (113) cures, the surface (101a) of the substrate (101) is coated with the inorganic phosphor dopant (100), any functional components (e.g., pigments for coloring), and a polymer.

[0109] When a phosphor is exposed to radiation, the orbital electrons within its molecules are excited to higher energy levels and, when they return to their original levels, they emit that energy as light of a specific color. In fact, the scintillation method in inorganic materials is due to the electronic band structure found in crystals. Incident particles can excite electrons from the valence band to the conduction band or the exciton band (located just below the conduction band and separated from the valence band by an energy gap). This leaves related holes in the valence band. Impurities create electron levels in the forbidden gap. An exciton is a loosely bound pair of an electron and a hole and diffuses through the crystal lattice until it is entirely captured by the center of the impurity. The latter then rapidly de-excites by emitting scintillation light (i.e., photons (105)). The wavelength emitted depends on the atom itself and the surrounding crystal structure.

[0110] In some embodiments, the ultraviolet light source (104) used to excite (i.e., charge) the orbital electrons of the inorganic phosphor dopant (100) has a wavelength between about 160 nm and 320 nm. In other embodiments, the ultraviolet light source (104) has a wavelength between about 160 nm and 260 nm, between about 160 nm and 200 nm, between about 180 nm and 240 nm, between about 200 nm and 250 nm, between about 210 nm and 250 nm, between about 225 nm and 260 nm, between about 230 nm and 250 nm, or between about 190 nm and 260 nm. In some other embodiments, the ultraviolet light source (104) has a wavelength of about 222 nm, 254 nm, or 275 nm.

[0111] Non-limiting examples of the ultraviolet light source (104) include, for example, black light, short-wavelength ultraviolet lamps, incandescent lamps, discharge lamps, ultraviolet LEDs, deuterium lamps, pulsed xenon light, and ultraviolet lasers. In one embodiment, the ultraviolet light source (104) is a pulsed xenon-ultraviolet device, which can be in the form of a handheld wand. The ultraviolet light emitted from the pulsed xenon device enables efficient charging of the inorganic phosphor dopant (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113), and by hovering the xenon-ultraviolet wand about 1 to 5 inches above the surface (101a), the coating surface (101a) can be disinfected. In another embodiment, the ultraviolet light source (104) is a deuterium lamp, which has light in the range of about 185 nm to about 400 nm.

[0112] In addition to the ultraviolet light source (104), other excitation energy sources may be used in the methods described herein. Personal protective equipment (PPE) may be required for the operation of such energy sources.

[0113] In some embodiments, the radiant energy used for disinfection may not have color (i.e., ultraviolet light). In some embodiments of the above method, the inorganic phosphor dopant (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) emits photons (105) having a wavelength of light between about 200 nm and 280 nm. In other embodiments, the inorganic phosphor dopant (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) emits photons (105) having a wavelength of light between about 200 nm and 270 nm, between about 200 nm and 250 nm, between about 225 nm and 250 nm, between about 200 nm and 225 nm, between about 200 nm and 275 nm, or between about 225 nm and 275 nm. The emission wavelength of the inorganic phosphor dopant (100) can be adjusted by changing the excitation wavelength of the phosphor. In a preferred embodiment, the inorganic phosphor dopant (100) emits UV-C light having a wavelength of about 200 to 280 nm.

[0114] In some embodiments, the inorganic phosphor dopant (100) is a metal oxide (106) or a metal fluoride (108) containing rare earth ions (107) or transition metal ions. In some embodiments, the rare earth ions (107) or transition metal ions are referred to as "activator ions". As used herein, an "activator ion" is an ion that is added as a dopant to a crystal structure. The activator ions are surrounded by host crystal ions and form emission centers where the excitation-emission process of the phosphor occurs. The wavelength emitted by the activator ions is affected by the ion itself, its electron coordination, and the surrounding crystal structure.

[0115] Activator ions have unique characteristics that contribute to the optical properties of the phosphor, but the electronic energy levels of the activator ions in the crystal are different from those of the free ions. The separation of the energy levels results in emission from ultraviolet to visible wavelengths depending on the properties of the host crystal. The local shape around the activator ions affects the spectroscopic behavior of the activator ions incorporated into the host matrix, particularly lanthanoid ions. Specific effects within the crystal lattice, such as ligand field splitting and center-of-gravity shifts, can affect the energy gap between the f and d orbitals of the activator ions, thereby potentially affecting the emission properties of such materials (Lin, YC., et al. Top Curr Chem(Z) 374, 21 (2016)).

[0116] In some embodiments, one or more inorganic phosphor dopants (100) are metal oxides (106) containing rare earth ions (107). In some embodiments, the rare earth ions (107) are lanthanide ions. In some embodiments, the rare earth ions (107) are m 3+ , Pr 3+ , Ho 3+ , Er 3+ , Sm 3+ , Nd 3+ , Yb 3+ , Eu 3+ , Eu 2+ , Gd 3+ , Ce 3+ , Ce 2+ , Tb 3+ , Tb4+ , Dy 3+ , Yb 3+ , and Lu 3+ , or selected from the group consisting of combinations thereof. In some embodiments, one or more inorganic phosphor dopants (100) are Pr 3+ , Ce 3+ , Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , or a metal oxide (106) containing rare earth ions (107) selected from the group consisting of mixtures thereof. In some embodiments, the rare earth ions (107) are Pr 3+ .

[0117] Pr 3+ -activated UV-C phosphor has a broad UV-C emission, and the parity-allowed Pr 3+ 4f 1 5d 1 ->4f 2 configuration transition is dominant. In the solid state, for the Pr 3+ 4f 1 5d 1 ->4f 2 transition to occur reliably, two general conditions are required. It is a small Stokes shift of less than about 3000 cm -1 (0.37 eV), and the appropriate energy position of the first (lowest energy) Pr 3+ 4f 2 ->4f 1 5d 1 excitation transition related to the composition and crystal structure of the host lattice. Under these conditions, the non-radiative relaxation from the Pr 3+ 4f 1 5d 1 level to the 4f 2 ( 3 P J , 1 I6, 1 D2) level is minimized. Otherwise, the 4f 1 5d 1 level and the 4f 2An intersection with the level occurs, resulting in a distinct line 4f of visible and infrared light emission 2 ->4f 2 Internal emission transmission within the structure becomes dominant (Wang, X., et al. Nat Commun 11, 2040 (2020)).

[0118] In some examples of one or more inorganic phosphor dopants (100), the metal oxide (106) (host lattice) is selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. Since such metal oxides (106) are ceramic materials, they exhibit several advantages including chemical, thermal, and photochemical stability. In some examples, the silicate is selected from the group consisting of melilite, cyclic silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7, (Ca,Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20 , and Y2SiO5 are included. Non-limiting examples of borates include YBO3 and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M = Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 , NaGdGeO4, Cd3Al2Ge3O 12 , CaTiO3, Ca 0.8 Zn 0.2 TiO3, and Ca2Zn4Ti 15 O 36 are included. Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O4、 CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 is included.

[0119] In some embodiments of one or more inorganic phosphor dopants (100), the metal oxide (106) is Pr 3+ (Ca2Al2SiO7 doped with Ca2Al2SiO7 (Ca2Al2SiO7:Pr 3+ ). Ca2Al2SiO7 has a merlite structure characterized in that Ca 2+ ions are sandwiched between layers in which tetrahedra of AlO4 and SiO4 are arranged alternately along the c-axis and are octahedrally coordinated. Each Ca 2+ ion is bonded to four nearest neighbor O 2- ligand ions, and thus the four Ca 2+ complexes within the unit cell are structurally equivalent. In Ca2Al2SiO7, Pr 3 +, trivalent Pr 3+ ions (1.126 Å) replace smaller divalent Ca 2+ ions (1.12 Å). Thus, the doped Pr 3+ ions are octahedrally coordinated. Such a highly coordinated, smaller, charge-imbalanced cation site can generate an appropriately strong crystal field for Pr 3+ ions, thereby resulting in a small Stokes shift and thus efficient Pr 3+ 4f 1 5d 1 ->4f 2 configurational transitions are likely to occur. Furthermore, without wishing to be bound by theory, the cation size mismatch and charge imbalance are expected to create more effective energy traps (e.g., oxygen vacancies) around Pr 3+ ions and assist in the formation of effective persistent phosphors (Wang, X., et al. Nat Commun 11, 2040 (2020)).

[0120] In some embodiments of one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors. In some embodiments, one or more inorganic phosphor dopants (100) are Pr 3+ doped Cs2NaYF6 (Cs2NaYF6:Pr 3+ ). In one embodiment, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 0.3% to about 10%. In other embodiments, Pr 3+ substitutes the yttrium ion sites of Cs2NaYF6 in an amount from about 1% to 5%, from 1.5% to 4.5%, from 2.5% to 5%, from 2% to 7%, from 3% to 8%, or from 4% to 9%.

[0121] The ink compositions (110) and / or ultraviolet curable ink compositions (113) described herein can be coated on substantially any surface (101a) for surface disinfection. Indeed, as described herein, the ink compositions (110) and / or ultraviolet curable ink compositions (113) have disinfection properties upon exposure to an ultraviolet light source (104). In some embodiments, the coated surface (101a) is located on an airplane, in a hospital, in a gymnasium, in a school, or in other areas where there is a high risk of vector movement.

[0122] In some embodiments of the above method, the coated surface (101a) is the interior of an airplane. In other embodiments of the above method, the coated surface (101a) is located in a hospital, in a gymnasium, or in a school. In another example of the above method, the surface (101a) is present in a place where there is a high risk of vector movement.

[0123] In an example of the above method for disinfecting a surface (101a), exposing the surface (101a) to an ultraviolet light source (104) is carried out for a time sufficient to charge one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113). In some examples, a time sufficient to charge one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) is from about 1 second to 2 seconds, 1 second to 30 seconds, 1 second to 25 seconds, 1 second to 20 seconds, 1 second to 15 seconds, 1 second to 10 seconds, 1 second to 5 seconds, 2 seconds to 5 seconds, 3 seconds to 15 seconds, 5 seconds to 10 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, 10 hours, 15 hours, 20 hours, or 24 hours. The amount of time sufficient to charge one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) varies depending on the wavelength of the ultraviolet light and the one or more inorganic phosphor dopants (100) themselves.

[0124] In an embodiment of the above method for disinfecting a surface (101a), one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) emit photons (105) for about 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, 25 minutes, 30 minutes, 45 minutes, or 60 minutes. The amount of time that one or more inorganic phosphor dopants (100) emit photons (105) can be adjusted, for example, by changing the length of time that one or more inorganic phosphor dopants (100) are charged. The duration of the emission can also be adjusted according to the desired application. For example, if the surface (101a) to be disinfected is located inside an airplane, the appropriate maximum emission time is about 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes so that the disinfection operation can proceed between flights. In some other embodiments, the longer the emission time, the more it can correlate with a higher disinfection level. For example, if the surface (101a) to be disinfected is located in a hospital or a medical facility, in this type of environment, a higher disinfection level may be desired, so the emission time can range between about 30 minutes and 60 minutes.

[0125] One or more dopant ions can be used not only to change the emission intensity but also to adjust the emissivity to a longer wavelength or a shorter wavelength. For example, doping SrAl2O4 with Eu 2 + results in a phosphor that emits light at 520 nm. However, SrAl2O4 can also be co-doped with Eu 2+ and Dy 3+ and acts to greatly enhance the persistent emission intensity. At room temperature, the afterglow of SrAl2O4:Eu 2+ , Dy 3+It lasts for several hours, which is the result of the charges trapped in the phosphor being gradually released by heat. Such long afterglow is in contrast to the mutant without codopant, whose duration is only a few minutes (Xingdong, L., et al. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 23, 652-657 (2008)). Furthermore, it can be stabilized with an inorganic phosphor dopant (100) having an energy trap that can be filled during excitation. The energy trap can be adjusted by adjusting the required penetration depth of UV energy to adjust the decay time required to decontaminate the surface (101a) over time.

[0126] When the light emitted by the inorganic phosphor dopant (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) material leaves the surface (101a), the surface (101a) is irradiated isotropically, thereby disinfecting the surface (101a). Isotropic irradiation refers to the radiation from a point source that irradiates uniformly with the same intensity in all directions regardless of the measurement direction. The light emitted by one or more inorganic phosphor dopants (100) is short-wavelength ultraviolet (ultraviolet C or UV-C) light having a wavelength range of 200 nm to 280 nm or 225 nm to 250 nm, which is known to have a bactericidal effect.

[0127] In some embodiments of the method for disinfecting the surface (101a), the ultraviolet light source (104) has a wavelength of about 160 to 260 nm, and one or more inorganic phosphor dopants (100) are 3+ a silicate containing Pr, and the inorganic phosphor dopant (100) emits photons (105) having a wavelength of light of about 265 nm.

[0128] VI. Method for improving the color stability of synthetic polymers Referring to FIG. 4, in some embodiments, the subject matter described herein relates to a method for improving the color stability of a synthetic polymer (121) including a surface (101a), the surface (101a) being coated with an ink composition (110) including one or more inorganic phosphor dopants (100), a solvent (111), and a binder (112), the method comprising, as shown in FIG. 4, at step 450, exposing the surface (101a) of the synthetic polymer (121) coated with the ink composition (110) to ultraviolet light to charge one or more inorganic phosphor dopants, wherein one or more inorganic phosphor dopants (100) in the ink composition (110) absorb the ultraviolet light, exposing the surface (101a) to ultraviolet light, and then at step 455, enabling one or more inorganic phosphor dopants (100) to emit the ultraviolet light as down-converted visible light (116), thereby creating a brighter appearance for the synthetic polymer (121).

[0129] Referring further to FIG. 4, in some other embodiments, the subject matter described herein relates to a method for improving the color stability of a synthetic polymer (121) including a surface (101a), the surface (101a) being coated with an ultraviolet curable ink composition (113) including one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115), the method comprising, as shown in FIG. 4, at step 450, exposing the surface (101a) of the synthetic polymer (121) coated with the ultraviolet curable ink composition (113) to ultraviolet light to charge one or more inorganic phosphor dopants, wherein one or more inorganic phosphor dopants (100) in the ultraviolet curable ink composition (113) absorb the ultraviolet light, exposing the surface (101a) to ultraviolet light, and then at step 455, enabling one or more inorganic phosphor dopants (100) to emit the ultraviolet light as down-converted visible light (116), thereby creating a brighter appearance for the synthetic polymer (121).

[0130] When a phosphor is exposed to radiation, the orbital electrons within its atoms are excited to higher energy levels and emit energy as light of a specific color when returning to their original levels. In fact, the scintillation process in inorganic materials is due to the electronic band structure found in crystals. Incident particles can excite electrons from the valence band to the conduction band or the exciton band (located just below the conduction band and separated from the valence band by an energy gap). This leaves associated holes in the valence band. Impurities create electron energy levels in the forbidden gap. An exciton is a loosely bound pair of an electron and a hole and spreads through the crystal lattice until it is entirely trapped by the impurity center. The latter then rapidly de-excites by emitting scintillation light (i.e., photons (105)). The wavelength emitted depends on the atom itself and the surrounding crystal structure.

[0131] As described herein, one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) absorb ultraviolet light and emit the ultraviolet light as down-converted visible light (116). In some embodiments, the ultraviolet light used to excite (charge) the orbital electrons of one or more inorganic phosphor dopants (100) has a wavelength between about 160 nm and 380 nm. In other embodiments, the ultraviolet light is between about 160 nm and 320 nm, between about 160 nm and 260 nm, between about 160 nm and 200 nm, between about 180 nm and 240 nm, between about 200 nm and 250 nm, between about 250 nm and 380 nm, between about 210 nm and 250 nm, between about 225 nm and 260 nm, between about 230 nm and 250 nm, or between about 190 nm and 260 nm. In some other embodiments, the ultraviolet light has a wavelength of about 222 nm, 254 nm, or 275 nm.

[0132] Non-limiting examples of the ultraviolet light source (104) used to provide ultraviolet light in the above method include, for example, black light, short-wavelength ultraviolet lamp, incandescent lamp, deuterium lamp, discharge lamp, ultraviolet LED, pulsed xenon light, and ultraviolet laser. For example, the ultraviolet light source (104) can be a pulsed xenon-ultraviolet device in the form of a handheld wand. The wand can be held, for example, at a distance of 1 to 5 inches from the coating surface (101a), and one or more inorganic phosphor dopants (100) in the ink composition (110) and / or ultraviolet curable ink composition (113) absorb ultraviolet light. In another embodiment, the ultraviolet light source (104) used to provide ultraviolet light is a deuterium lamp, which has light in the range of about 185 nm to about 400 nm.

[0133] In addition to the ultraviolet light source (104), other excitation energy sources may be used in the methods described herein. Personal protective equipment (PPE) may be required for the operation of such energy sources.

[0134] In some embodiments of the above method for improving the color stability of the synthetic polymer (121), the absorption of ultraviolet light by one or more inorganic phosphor dopants (100) reduces the photooxidation of the synthetic polymer (121). As used herein, the reduction of photooxidation of the synthetic polymer (121) refers to the reduction of discoloration and / or embrittlement of the synthetic polymer (121) due to exposure to ultraviolet light, by one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) that coat the surface (101a) of the synthetic polymer (121), which absorb most of the ultraviolet light instead of the synthetic polymer (121) itself. Considering that the ultraviolet absorption behavior varies among synthetic polymers (121), the specific reduction of photooxidation is material-dependent. One or more inorganic phosphor dopants (100) generally exhibit very strong absorption. Thus, incorporating one or more inorganic phosphor dopants (100) into the ink composition (110) and / or the ultraviolet curable ink composition (113) that coat the surface (101a) of the synthetic polymer (121) can reduce the photooxidation of the synthetic polymer (121) by up to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% compared to the synthetic polymer (121) whose surface (101a) is not coated with the ink composition (110) and / or the ultraviolet curable ink composition (113) described herein. The photooxidation of the material can be detected, for example, using infrared spectroscopy. In particular, the peroxide species and carbonyl groups formed by photooxidation often have distinct absorption bands.

[0135] In some embodiments of the method for improving the color stability of the synthetic polymer (121), the visible light (116) emitted by one or more inorganic phosphor dopants (100) produces a brighter appearance in the synthetic polymer (121). The brighter appearance is perceived by a viewer observing the synthetic polymer (121). In fact, as used herein, "brightness" is an attribute of visual perception such that a light source appears to be emitting or reflecting light. Brightness is the perception caused by the luminance of the visual object. In some embodiments, one or more inorganic phosphor dopants (100) can emit blue visible light (116) having a wavelength between 450 nm and 495 nm. The blue visible light (116) emitted from an ink composition (110) and / or an ultraviolet curable ink composition (113) comprising one or more inorganic phosphor dopants (100) that coats the surface (101a) of the synthetic polymer (121) can visually offset the yellow discoloration of the synthetic polymer (121). The foregoing effect is similar to the effect of broad visible light emission, where certain dopants in a material that emits broad light have the effect of making the entire material appear visually brighter.

[0136] In some embodiments of the method for improving the color stability of the synthetic polymer (121), the light emitted by one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) is down-converted visible light (116). In some embodiments of the above method, one or more inorganic phosphor dopants (100) emit visible light (116) having a wavelength between about 200 and 700 nm. In other embodiments, one or more inorganic phosphor dopants (100) are between about 400 nm and 495 nm, between about 620 nm and 700 nm, between about 590 nm and 620 nm, between about 570 nm and 590 nm, between about 495 nm and 570 nm, between about 390 nm and 450 nm, between about 380 nm and 600 nm, between about 350 nm and 460 nm, between about 600 nm and 700 nm, between about 450 nm and 600 nm, between about 200 nm and 280 nm, between about 450 nm and 495 nm, between about 380 nm and 450 nm, between about 200 nm and 270 nm, between about 200 nm and 250 nm, between about 225 nm and 250 nm, between about 200 nm and 225 nm, between about 200 nm and 275 nm, or between about 225 nm and 275 nm and emit visible light (116) having a wavelength therebetween. The specific wavelength or range of wavelengths can be selected based on the desired color of the emitted light. For example, if it is desired for the inorganic phosphor dopant (100) to emit blue light, a phosphor that emits visible light (116) having a wavelength between about 400 nm and 495 nm will be selected. In some other embodiments, if it is desired for the inorganic phosphor dopant (100) to emit green light, a phosphor that emits visible light (116) having a wavelength between about 495 and 570 nm will be selected. In other embodiments, if it is desired for the inorganic phosphor dopant (100) to emit purple light, a phosphor that emits visible light (116) having a wavelength between about 380 nm and 450 nm will be selected. In some other embodiments, if it is desired for the inorganic phosphor dopant (100) to emit yellow light, a phosphor that emits visible light (116) having a wavelength between about 570 nm and 590 nm will be selected.In a further embodiment, if it is desirable for the inorganic phosphor dopant (100) to emit orange light, a phosphor that emits visible light (116) having a wavelength between about 590 nm and 620 nm will be selected. Further, in other embodiments, if it is desirable for the inorganic phosphor dopant (100) to emit red light, a phosphor that emits visible light (116) having a wavelength between about 620 nm and 700 nm will be selected.

[0137] In some embodiments of the method for improving the color stability of a synthetic polymer (121), the ink composition (110) and / or the ultraviolet curable ink composition (113) for coating the surface (101a) of the synthetic polymer (121) comprises two or more inorganic phosphor dopants (100), and the down-converted visible light (116) emitted by the two or more inorganic phosphor dopants (100) combines to produce white or off-white light. In some embodiments of the method for improving the color stability of a synthetic polymer (121), the ink composition (110) and / or the ultraviolet curable ink composition (113) for coating the surface (101a) of the synthetic polymer (121) comprises three or more inorganic phosphor dopants (100), and the down-converted visible light (116) emitted by the three or more inorganic phosphor dopants (100) combines to produce white or off-white light. For example, an inorganic phosphor dopant (100) that emits blue visible light (116) having a wavelength between about 450 nm and 495 nm can be incorporated into the ink composition (110) and / or the ultraviolet curable ink composition (113) that coats the surface (101a) of the synthetic polymer (121) with a second inorganic phosphor dopant (100) that emits yellow visible light (116) having a wavelength between about 570 nm and 590 nm. The combination of the blue and yellow visible light (116) emitted by the first and second inorganic phosphor dopants (100) produces white or off-white emission (white visible light (116)). Similarly, a first inorganic phosphor dopant (100) that emits blue visible light (116) having a wavelength between about 450 nm and 495 nm can be incorporated into the ink composition (110) and / or the ultraviolet curable ink composition (113) that coats the surface (101a) of the synthetic polymer (121) together with a second inorganic phosphor dopant (100) that emits green visible light (116) having a wavelength between about 495 nm and 570 nm, and a third inorganic phosphor dopant (100) that emits red visible light (116) having a wavelength between about 620 nm and 750 nm.The combination of blue, green, and red visible light (116) emitted by the first, second, and third inorganic phosphor dopants (100) will result in white or off-white emission (white visible light (116)).

[0138] In some embodiments of the method for improving the color stability of the synthetic polymer (121), the synthetic polymer (121) having a surface (101a) is thermoplastic or thermosetting. In some embodiments, the synthetic polymer (121) is selected from the group consisting of tetrafluoroethylene, polyvinyl fluoride, polyurethane, polyester, epoxy, phenol, vinyl ester, polyamide, polyamide-imide, polyetherimide, polyvinyl chloride, polyether ketone ketone, polycarbonate, polyphenyl sulfone, polymethyl methacrylate, polyacrylate, and benzoxazine. In particular, fluorine is known to be highly resistant to photooxidation because of its high electronegativity and tendency to accept electrons. Thus, in some embodiments, fluorinated synthetic polymers such as tetrafluoroethylene or polyvinyl fluoride are useful as the synthetic polymer (121) in the methods described herein. Additionally, thermosetting polymers are generally known to have a higher degree of crosslinking compared to other types of polymers, which further enhances their resistance to photooxidation.

[0139] In some embodiments of the method for improving the color stability of the synthetic polymer (121), one or more inorganic phosphor dopants (100) are metal oxides (106) or metal fluorides (108) containing rare earth ions (107) or transition metal ions. Rare earth ions (107) or transition metal ions are referred to as "activator ions". As used herein, an "activator ion" is an ion that is added as a dopant to the crystal structure. Activator ions are surrounded by host crystal ions and form the luminescence centers where the excitation-emission process of the phosphor occurs. The wavelength emitted by the activator ions depends on the ion itself, its electron coordination, and the surrounding crystal structure. In some embodiments, the rare earth ions (107) are lanthanide ions. In some embodiments, the rare earth ions (107) are m 3+,Pr 3+ , Ho 3+ , Er 3+ , Sm 3+ , Nd 3+ , Yb 3+ ,EU 3+ ,EU 2+ , Gd 3+ , Ce 3+ , Ce 2+ , Tb 3+ , Tb 4+ , Dy 3+ , Yb 3+ , Y 3+ , and Lu 3+ In some embodiments, the one or more inorganic phosphor dopants (100) are selected from the group consisting of Pr 3+ , Ce 3+ ,EU 3+ ,EU 2+ , Gd 3+ , Tb 3+ , and Dy 3+ In some embodiments, the one or more inorganic phosphor dopants (100) are metal oxides (106) or metal fluorides (108) that include rare earth ions (107) selected from the group consisting of: , , or mixtures thereof. In some embodiments, the one or more inorganic phosphor dopants (100) are metal oxides (106) that include rare earth ions (107). In embodiments, the rare earth ions (107) are selected in combination with the metal oxides (106) to prepare an inorganic phosphor dopant (100) that emits light having a particular color and wavelength. For example, Eu doped in YO3 3+ is expected to emit red-orange visible light with a wavelength of about 611 nm (116), and Eu doped in InBO 3+ is expected to emit yellow visible light (116) having a wavelength of about 588 nm. 16 O 27 Eu doped in 2+ can be selected, which is expected to emit blue visible light (116) having a wavelength of about 450 nm.

[0140] In some embodiments of a method for improving the color stability of a synthetic polymer (121), one or more inorganic phosphor dopants (100) are metal fluorides (108) selected from the group consisting of Cs2NaYF6, NaCeF4, NaYF4, and NaGd4, which contain rare earth ions (107) or transition metal ions. Such metal fluoride (108) hosts often have the characteristics of a large bandgap, structural defects that are likely to act as electron traps, and anionic defects that make it useful for inorganic phosphors.

[0141] In some embodiments of a method for improving the color stability of a synthetic polymer (121), one or more inorganic phosphor dopants (100) are metal oxides (106) selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some embodiments, the silicate is selected from the group consisting of melilite, cyclic silicate, silicate garnet, oxyorthosilicate, and orthosilicate. Non-limiting examples of silicates include Sr2MgSi2O7, Ca2Al2SiO7, SrAl2O4, MgSiO3, SrSiO3, CdSiO3, Ba2SiO4, BaMg2Si2O7, Ca2MgSi2O7, Sr 0.5 Ca 1.5 MgSi2O7,(Ca,Sr)2MgSi2O7, Sr3MgSi2O8, Sr2MgSi2O7, Ca 0.5 Sr 1.5 Al2SiO7, Sr3Al 10 SiO 20 、and Y2SiO5 are included. Non-limiting examples of borates include YBO3, InBO3, and CaAl2B2O7. Non-limiting examples of oxynitrides include MSi2O2N2 (M is Ba, Sr, or Ca). Non-limiting examples of phosphates include YPO4 and Zn3(PO4)2. Non-limiting examples of oxides include CaO, SrO, BaO, Y3Ga5O 12 、NaGdGeO4, Cd3Al2Ge3O 12 、CaTiO3, Ca 0.8 Zn 0.2TiO3 and Ca2Zn4Ti 15 O 36 is included. Non-limiting examples of oxysulfides include Y2O2S, Gd2O2S, and Sr5Al2O7S. Non-limiting examples of aluminates include MgAl2O 4、 CaAl2O4, SrAl2O4, and Sr4Al 14 O 25 is included.

[0142] In some embodiments, the ink composition (110) and / or the ultraviolet curable ink composition (113) that coats the surface (101a) of the synthetic polymer (121) includes two different inorganic phosphor dopants (100), and each inorganic phosphor dopant (100) is a metal oxide (106) or a metal fluoride (108) containing rare earth ions (107), and the combined emission of the two inorganic phosphor dopants (100) produces white or off-white visible light (116). In some embodiments, the ink composition (110) and / or the ultraviolet curable ink composition (113) that coats the surface (101a) of the synthetic polymer (121) includes two different inorganic phosphor dopants (100), and the two different inorganic phosphor dopants (100) are metal oxides (106) containing rare earth ions (107). As an example, the ink composition (110) and / or the ultraviolet curable ink composition (113) that coats the surface (101a) of the synthetic polymer (121) can include a first inorganic phosphor dopant (100) of Y2SiO5:Ce(III) that emits blue visible light (116) having a wavelength of about 400 nm and a second inorganic phosphor dopant (100) of InBO3:Eu(III) that emits yellow visible light (116) having a wavelength of about 588 nm. The combined visible light (116) produces white or off-white visible light (116).

[0143] In some embodiments, the ink composition (110) and / or the ultraviolet curable ink composition (113) that coat the surface (101a) of the synthetic polymer (121) include three different inorganic phosphor dopants (100), each inorganic phosphor dopant (100) being a metal oxide (106) or a metal fluoride (108) containing rare earth ions (107), and the combined emission of the three inorganic phosphor dopants (100) produces white or off-white visible light (116). For example, in some embodiments, the ink composition (110) and / or the ultraviolet curable ink composition (113) that coat the surface (101a) of the synthetic polymer (121) emit blue visible light (116) having a wavelength of about 450 nm BaMg2Al 16 O 27 :Eu(II) as the first inorganic phosphor dopant (100), Y2SiO5:Tb(III) as the second inorganic phosphor dopant (100) that emits green visible light (116) having a wavelength of about 545 nm, and Y2O3:Eu(III) as the third inorganic phosphor dopant (100) that emits red visible light (116) having a wavelength of about 611 nm. The combined visible light (116) results in white or off-white visible light (116).

[0144] In some embodiments of a method for improving the color stability of a synthetic polymer composition, the surface (101a) of the synthetic polymer (121) is located inside an airplane. In other embodiments, the surface (101a) of the synthetic polymer (121) is the surface (101a) located on a substrate (101), or in a hospital or other medical facility, school, gymnasium, or automobile.

[0145] In some embodiments of the method for improving the color stability of a synthetic polymer composition, exposing the surface (101a) to ultraviolet light is carried out for a time sufficient to charge one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113). In some embodiments, a time sufficient to charge one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the ultraviolet curable ink composition (113) is about 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, 10 hours, 15 hours, 20 hours, or 24 hours.

[0146] One or more inorganic phosphor dopants (100) absorb ultraviolet light and emit the ultraviolet light as down-converted visible light (116) generally over a time on the order of nanoseconds. Further, in an embodiment, the phosphor absorbs energy and does not immediately emit light. Rather, in an embodiment, the energy dissipates in picoseconds to the lowest excited state prior to emission. In some embodiments, by application of continuous illumination, for example, one or more inorganic phosphor dopants (100) absorb ultraviolet light and continuously emit the ultraviolet light as down-converted visible light (116).

[0147] In some other embodiments, persistent phosphors can be applied to the above method for improving the color stability of the synthetic polymer (121). Persistent phosphors exhibit luminescence that persists from several seconds to several hours after excitation ceases, which is different from normal conversion phosphors. The reason for such delayed emission is probably its ability to store energy in defects other than luminescent "activator" ions in the material. Such defects are called traps because charge carriers derived from luminescent ions are locally trapped in the defects. When sufficient energy is supplied to the trapped charge, the charge is released. After recombination at the luminescent ions, delayed emission, generally called afterglow, occurs. The time width of the afterglow depends on the so-called trap depth, which is usually investigated by thermoluminescence, and thus can be adjusted. For example, it is generally understood that shallow traps are easily emptied, while deep traps are difficult to empty at room temperature and a portion of the trapped photons remain stored there. If the trap is too deep, the trapped electrons cannot escape, preventing persistent afterglow. Thermoluminescence can be used to evaluate the trap depth. In fact, the glow curve of thermoluminescence represents the luminescence intensity versus temperature, and each glow peak is associated with a recombination center and is related to a specific trap. The glow curve can provide useful information about the material. The activation energy and escape frequency coefficient can be calculated, for example, from the glow curve. Many methods, such as the initial rise method and variable heating rate, can be used to calculate trap parameters based on the kinetic order of the glow peak. The luminescence efficiency of the material can be obtained based on the glow curve.

[0148] The change in the structure-luminescence characteristics of the material can be observed through the change in its glow curve. The decrease in the thermoluminescence intensity may be due to, for example, the suppression of traps. In other embodiments, adding impurities (e.g., another ion) to the phosphor may increase the luminescence efficiency of the material. The presence of such impurities can change the trap distribution and may deepen the trap sites caused by the change in the energy gap of the phosphor. The thermoluminescence glow curve can be obtained using a thermoluminescence meter such as an FJ-427A TL meter.

[0149] In some other embodiments, the electronic transitions of the phosphor can be characterized as "forbidden." Forbidden transitions are spectral lines associated with the absorption or emission of photons (105) by nuclei or atoms that occur via transitions that are not permitted by certain selection rules but are permitted when approximations associated with those rules are not made. For example, according to normal approximations (such as the electric dipole approximation for interactions with light), the process cannot occur, but in situations where it occurs with a higher level of approximation (i.e., magnetic dipole), the process becomes possible at a lower rate. One example of such a forbidden transition is observed in phosphorescent, glow-in-the-dark materials that absorb light and form an excited state whose decay involves a spin flip that is forbidden by electric dipole transitions. As a result, light is emitted slowly over minutes or hours. In fact, "forbidden" transitions occur at a much lower rate than "allowed" transitions. "Allowed" transitions are those that follow appropriate (1) spin and (2) Laporte (orbital) selection rules, exhibit a change in parity (symmetry) during the transition, emit a photon having an energy that matches the gap between the ground state and the excited state, and exhibit a change in dipole moment. The allowed spin selection rule states that the orientation of the spin does not change (i.e., there is no spin flip during the electron transition). According to the Laporte selection rule, in a centrosymmetric environment, transitions between like atomic orbitals such as s-s transitions, p-p transitions, d-d transitions, or f-f transitions are forbidden. Even if a transition is forbidden, it is often coupled with a vibrational factor, for example, reducing the molecular symmetry of the system and making a transition that was previously forbidden become allowed due to the reduced symmetry. As a result, weakly allowed transitions often occur and the transition rate decreases. The typical luminescence lifetime of a material undergoing a forbidden transition can be in the milliseconds or, in some cases, seconds.

[0150] As described above, one or more inorganic phosphor dopants (100) can be used to adjust the emissivity to longer or shorter wavelengths and, in some embodiments, to create white light.

[0151] In some embodiments of a method for improving the color stability of a synthetic polymer (121), the synthetic polymer (121) is a thermoplastic material, and the ink composition (110) and / or the ultraviolet curable ink composition (113) contain two inorganic phosphor dopants (100), the first inorganic phosphor dopant (100) is Y2SiO5:Ce(III) that emits blue visible light (116) having a wavelength of about 400 nm, and the second inorganic phosphor dopant (100) is InBO3:Eu(III) that emits yellow visible light (116) having a wavelength of about 588 nm. The phosphors in the ink composition (110) and / or the ultraviolet curable ink composition (113) that coat the synthetic polymer (121) are exposed to ultraviolet light for approximately 10 minutes using a xenon-ultraviolet wand before emitting visible light (116), and these are combined to produce white visible light (116).

[0152] Furthermore, the present disclosure includes embodiments according to the following clauses.

[0153] Clause 1. An ink composition comprising one or more inorganic phosphor dopants, a solvent, and a binder.

[0154] Clause 2. The ink composition according to Clause 1, wherein one or more inorganic phosphor dopants have a diameter of 0.5 μm or less.

[0155] Clause 3. The ink composition according to Clause 1 or 2, wherein one or more inorganic phosphor dopants are each independently selected from the group consisting of metal oxides and metal fluorides containing rare earth ions selected from the group consisting of Pr 3+ , Ce 3+ , Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , or mixtures thereof.

[0156] Clause 4. The ink composition according to Clause 3, wherein the rare earth ion is Pr 3+ .

[0157] Clause 5. The ink composition according to Clause 3 or 4, wherein the metal oxide is in each case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof.

[0158] Clause 6. The ink composition according to any one of Clauses 1 to 5, wherein the solvent is selected from the group consisting of water, methanol, ethanol, propanol, isopropyl alcohol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethyl sulfoxide, ethylene glycol ether, propylene glycol ether, esters, cyclohexanone, isophorone, and alkyl lactate.

[0159] Clause 7. The ink composition according to any one of Clauses 1 to 6, wherein the binder is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane, polyvinyl alcohol, vinyl chloride / vinyl acetate copolymer, acrylics, and polyketones.

[0160] Clause 8. The ink composition according to any one of Clauses 1 to 7, having a viscosity of from about 2 mPa·s to about 30 mPa·s.

[0161] Clause 9. The ink composition according to any one of Clauses 1 to 8, formulated as an aerosol spray.

[0162] Clause 10. An ultraviolet curable ink composition comprising one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers.

[0163] Clause 11. The ultraviolet curable ink composition according to Clause 10, wherein one or more inorganic phosphor dopants have a diameter of 0.5 μm or less.

[0164] Clause 12. One or more inorganic phosphor dopants are each independently Pr 3+ , Ce 3+, Eu 3+ , Eu 2+ , Gd 3+ , Tb 3+ , and Dy 3+ , A UV-curable ink composition according to clause 10 or 11, comprising a metal oxide and a metal fluoride selected from the group consisting of rare earth ions selected from the group consisting of or mixtures thereof.

[0165] Clause 13. The rare earth ion is Pr 3+ , A UV-curable ink composition according to clause 12.

[0166] Clause 14. The metal oxide is in each case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof, a UV-curable ink composition according to clause 12 or 13.

[0167] Clause 15. One or more photoinitiators are each independently selected from the group consisting of 4,4′-bis(dimethylamino)benzophenone, thioxanthen-9-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,4-dinitro-1-naphthol, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), azobisisobutyronitrile (AIBN), benzyldimethylketal (BDK, Irgacure 651), 2-hydroxy-methyl-1-phenylpropane (Darocure 1173), hydroxycyclohexylphenylketone, (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, monoacylphosphine oxide (Lucerin TPO), Esacure KIP150, monoacylphosphine oxide (MAPO) and bisacylphosphine oxide photoinitiator (BAPO), a UV-curable ink composition according to any of clauses 10 to 14.

[0168] Clause 16. One or more monomers are each independently an acrylate monomer, a UV-curable ink composition according to any of clauses 10 to 15.

[0169] Clause 17. The ultraviolet curable ink composition according to any one of Clauses 10 to 16, further comprising one or more additives for reducing surface tension and / or improving wettability of the substrate.

[0170] Clause 18. The ultraviolet curable ink composition according to any one of Clauses 10 to 17, having a viscosity of from about 5 mPa·s to about 35 mPa·s.

[0171] Clause 19. An ink composition according to any one of Clauses 1 to 9, or an ultraviolet curable ink composition according to any one of Clauses 10 to 18, wherein the ink composition has disinfecting properties upon exposure to an ultraviolet light source.

[0172] Clause 20. A synthetic polymer comprising a surface, the surface being coated with at least one coating of an ink composition according to any one of Clauses 1 to 9, or an ultraviolet curable ink composition according to any one of Clauses 10 to 18, the coating providing improved color stability to the synthetic polymer.

[0173] Clause 21. A method for disinfecting a surface, the surface being coated with an ink composition according to any one of Clauses 1 to 9 or an ultraviolet curable ink composition according to any one of Clauses 10 to 18, the method comprising exposing the surface to an ultraviolet light source, the exposure causing one or more inorganic phosphor dopants in the ink composition to emit photons that irradiate the surface, thereby disinfecting the surface.

[0174] Clause 22. The method according to Clause 21, wherein the one or more inorganic phosphor dopants emit photons having a wavelength of light between about 200 nm and 280 nm.

[0175] Clause 23. The method according to Clause 21 or 22, wherein the one or more inorganic phosphor dopants emit photons having a wavelength of light between about 225 and 250 nm.

[0176] Clause 24. The method according to any one of Clauses 21 to 23, wherein the ultraviolet light source has a wavelength between about 160 nm and 320 nm.

[0177] Clause 25. The method according to any one of Clauses 21 to 24, wherein the ultraviolet light source has a wavelength of about 222 nm, 254 nm, or 275 nm.

[0178] Clause 26. A method for improving the color stability of a synthetic polymer including a surface, wherein the surface is coated with the ink composition according to any one of Clauses 1 to 9 or the ultraviolet curable ink composition according to any one of Clauses 10 to 18, the method including exposing the surface to ultraviolet light, and one or more inorganic phosphor dopants in the ink composition absorb the ultraviolet light and then emit it as down-converted visible light.

[0179] Clause 27. The method according to Clause 26, wherein the presence of the ink composition coating the surface reduces photooxidation of the synthetic polymer.

[0180] Clause 28. The method according to Clause 26 or 27, wherein the visible light emitted by one or more inorganic phosphor dopants in the ink composition generates a brighter appearance for the synthetic polymer.

[0181] Clause 29. The method according to any one of Clauses 26 to 28, wherein the ink composition includes two or more inorganic phosphor dopants, and the down-converted visible light emitted by the two or more inorganic phosphor dopants is combined to produce white or off-white visible light.

[0182] Clause 30. The method according to any one of Clauses 26 to 28, wherein the ink composition includes three or more inorganic phosphor dopants, and the down-converted visible light emitted by the three or more inorganic phosphor dopants is combined to produce white or off-white visible light.

[0183] Clause 31. The method according to any one of Clauses 26 to 30, wherein the ultraviolet light absorbed by one or more inorganic phosphor dopants has a wavelength between about 160 nm and 380 nm.

[0184] Clause 32. The method according to any one of Clauses 26 to 31, wherein the synthetic polymer is thermoplastic or thermosetting.

[0185] Clause 33. The method according to any one of Clauses 26 to 32, wherein the synthetic polymer is selected from the group consisting of tetrafluoroethylene, polyvinyl fluoride, polyurethane, polyester, epoxy, phenol, vinyl ester, polyamide, polyamide-imide, polyetherimide, polyvinyl chloride, polyether ketone ketone, polycarbonate, polyphenyl sulfone, polymethyl methacrylate, polyacrylate, and benzoxazine.

[0186] Clause 34. A method for producing an ink composition according to any one of Claims 1 to 9, comprising contacting a solvent with one or more inorganic phosphor dopants and a binder, wherein the ink composition is prepared.

[0187] Clause 35. A method for producing an ultraviolet curable ink composition according to any one of Claims 10 to 18, comprising contacting one or more inorganic phosphor dopants with one or more photoinitiators and one or more monomers, wherein the ultraviolet curable ink composition is prepared.

[0188] The following examples are provided for illustrative purposes and not for purposes of limitation. One of ordinary skill in the art will understand that other synthetic routes may be used to synthesize the inorganic phosphor dopant (100) and inorganic phosphor-doped substrate materials described herein. Although specific starting materials and reagents are shown and described in the examples, other starting materials and reagents may be readily substituted to provide various derivative materials and / or reaction conditions. Additionally, many of the exemplary materials prepared by the methods described can be further modified in light of the present disclosure using conventional chemical substances well known to one of ordinary skill in the art.

Example

[0189] Example 1: Preparation of a Photon-Emitting Inorganic Phosphor-Doped Ink Composition Coating Substrate (Ca 2-x Al2SiO7: x Pr 3+ -Doped Polyvinyl Fluoride) Step 1. Ca 2-x Al 2 SiO 7 : x Pr 3+ Preparation CaO, Al2O3, SiO2, and Pr6O 11 were purchased from Sigma Aldrich. CaO, Al2O3, SiO2, and Pr6O 11 are weighed so that the amount of Pr6O 11 in the mixture results in a 0.5 - 5% substitution of praseodymium on the calcium sites. The powder is then ground using an agate mortar and pestle for approximately 5 minutes until a fine grey mixture of the powder is formed. Subsequently, the mixed powder is placed in a ceramic alumina crucible and pre-fired in air at 900 °C for 2 hours. This is followed by completely grinding the mixed powder using an agate mortar and pestle for approximately 3 minutes. The mixed powder is then returned to the alumina crucible, placed in a furnace, and heated in air at 1300 °C for 7 hours. The powder is removed from the furnace and cooled to room temperature.

[0190] The prepared Ca2-x Al2SiO7: x Pr 3+ The inorganic phosphor dopant (100) is analyzed by powder X-ray diffraction. The crystal structure is analyzed using FullProf to verify the Ca / Pr site mixing in the Ca2Al2SiO7 crystal structure.

[0191] Step 2. Ca 2-x Al 2 SiO 7 : x Pr 3+ Preparation of doped coating substrate The Ca prepared in Step 1 2-x Al2SiO7: x Pr 3+ The powder is thoroughly mixed with one or more solvents (111) and one or more binders (112) such that the Ca 2-x Al2SiO7: x Pr 3+ and one or more binders (112) are uniformly incorporated into the one or more solvents (111), thereby forming an ink composition (110). Using a piezoelectric print head, the ink composition (110) is inkjet printed onto the surface (101a) of a host substrate (101) material to form a Ca 2-x Al2SiO7: x Pr 3+ doped coating substrate (101) material. The ink composition (110) is then cured.

[0192] Example 2: Disinfection using an inorganic phosphor-doped ink composition coating substrate material (Ca 2-x Al2SiO7: x Pr 3+ doped coating substrate) The Ca prepared in Step 2 2-x Al2SiO7: x Pr 3+The doped coated substrate (101) material is exposed to an ultraviolet light source (104) having a wavelength between about 160 nm and 280 nm, which dissolves the Ca in the ink composition (110) coated on the surface (101a) of the host substrate (101) material. 2-x Al2SiO7: x Pr 3+ is the radiative excitation energy of the phosphor. Ca 2-x Al2SiO7: x Pr 3+ The doped coated substrate (101) material is exposed to an ultraviolet light source (104), such as an ultraviolet lamp, for approximately 2 to 10 minutes to form a Ca 2-x Al2SiO7: x Pr 3+ The phosphor is charged. Then the ultraviolet light source (104) is turned off. Then, the Ca coated on the substrate (101) material is 2-x Al2SiO7: x Pr 3+ The phosphor emits light in the range of 200 nm to 280 nm for about 2 to 10 minutes. This emission range corresponds to UV-C light, which is known to have germicidal effects. 2-x Al2SiO7: x Pr 3+ The germicidal light emitted by the phosphor is 2-x Al2SiO7: x Pr 3+ The surface (101a) of the doped coated substrate (101) material is irradiated, thereby sterilizing the surface (101a).A spectrofluorometer is used to measure the afterglow intensity of the phosphor doped substrate (101) material.

[0193] In another embodiment, the ultraviolet light source (104) can be a pulsed xenon-ultraviolet device or a pulsed xenon lamp, having a wavelength of about 222 nm, 254 nm, or 275 nm, and irradiating the Ca prepared in step 2. 2-x Al2SiO7: x Pr 3+ The doped coating of the substrate (101) material is exposed to the Ca 2-x Al2SiO7: x Pr3+ The surface (101a) of the doped coated substrate (101) material is exposed to an ultraviolet light source (104), such as a pulsed xenon-ultraviolet device having a wavelength of 254 nm, for approximately 2 minutes. When the excitation light is removed, a UV-C continuous emission at 268 nm is obtained. Ca 2-x Al2SiO7: x Pr 3+ Doped coating substrate (101) material with Pr 3+ The observation of UV-C afterglow of Ca 2-x Al2SiO7: x Pr 3+ The energy traps in the phosphor can be effectively filled by 254 nm light excitation, and the energy traps are converted to Pr 3+ 4f 1 5d 1 The electrons are efficiently captured from the 4f state and released by the surrounding thermal stimulation after the excitation is stopped. 1 5d 1 This suggests that the electrons are in the right energy position to be able to return to the Ca state. 2-x Al2SiO7: x Pr 3+ The surface (101a) of the doped coated substrate (101) material is effectively disinfected. A spectrofluorometer is used to measure the afterglow intensity of the phosphor doped surface (101a) of the substrate (101) material.

[0194] Example 3: Photon-emitting inorganic phosphor doped coated substrate material (NaY( 1-x )F6: x Pr 3+ Preparation of doped tetrafluoroethylene Step 1. NaY( 1-x )F 6 : x Pr 3+ Preparation Cs2NaY( 1-x )F6: x Pr 3+A Pr-doped polycrystalline fluoride elpasolite phosphor having a nominal composition of (x = 0.01~0.10) is prepared by solid-state synthesis. Cs2CO3 (1.6290 g, 99.99%, Aladdin, Shanghai, China), NaHCO3 (0.4200 g, 99.99%, Aladdin, Shanghai, China), Y2O3 (0.5588 g, 99.99%, Aladdin, Shanghai, China), NH4F (2.2222 g, 99.99%, Aladdin, Shanghai, China), and Pr6O 11 The powder of (0.0085 g, 99.996%, Alfa, USA) is mixed with 3 mL of acetone and then ground thoroughly for about 5 minutes. The resulting powder is heat-treated in air at 150 °C for 7 hours and then ground again to obtain a fine powder. This mixture is then sintered in air at 450 °C for 30 minutes. The obtained powder is then ground again and subsequently sintered in a nitrogen atmosphere at 700 °C for 10 hours. For the above synthesis, a corundum boat and a platinum crucible with a purity of 99% are used as containers.

[0195] The prepared Cs2NaY( 1-x )F6: x Pr 3+ The inorganic phosphor dopant (100) is analyzed by powder X-ray diffraction. The crystal structure is analyzed using FullProf, and the Y / Pr site mixing in the Cs2NaY( 1-x )F6: x Pr 3+ crystal structure is verified. The structure crystallizes in the Fm-3m space group corresponding to cubic elpasolite. In this double perovskite structure, both Y and Na are coordinated with six fluorine atoms, and the doped Pr 3+ ions replace the Y 3+ ions.

[0196] Step 2. Cs 2 NaY( 1-x )F 6 : x Pr 3+ Preparation of doped coating tetrafluoroethylene The Cs2NaY( 1-x )F6: x Pr prepared in Step 13+ The powder is Cs2NaY( 1-x )F6: x Pr 3+ and the binder (112) are uniformly incorporated into the solvent (111) and are thoroughly mixed with the solvent (111) and the binder (112) such that an ink composition (110) is formed. Using a piezoelectric print head, the ink composition (110) is printed onto the surface (101a) of the host substrate (101) material to form a Cs2NaY( 1-x )F6: x Pr 3+ doped coating substrate material. The ink composition (110) is then cured to form a solidified Cs2NaY( 1-x )F6: x Pr 3+ doped coating on the surface (101a) of the tetrafluoroethylene substrate (101) material.

[0197] Example 4: Disinfection using an inorganic phosphor doped coating substrate material (Cs2NaY( 1-x )F6: x Pr 3+ doped coating tetrafluoroethylene) The Cs2NaY( 1-x )F6: x Pr 3+ doped coating tetrafluoroethylene substrate (101) material prepared in Step 2 is exposed to an ultraviolet light source (104), such as a pulsed xenon lamp, having a wavelength between 100 nm and 225 nm for approximately 30 seconds. The pulsed light is sufficient to charge the Cs2NaY( 1-x )F6: x Pr 3+ phosphor on the coating surface (101a) of the tetrafluoroethylene substrate (101) material. Then the Cs2NaY( 1-x )F6: x Pr 3+ phosphor in the coating emits light (germicidal light) in the range from 200 nm to 280 nm for about 10 to 20 minutes. The Cs2NaY( 1-x )F6: x Pr 3+The germicidal light emitted by the phosphor is Cs2NaY( 1-x )F6: x Pr 3+ Isotropically irradiates the surface (101a) of the doped coating tetrafluoroethylene substrate (101) material, thereby disinfecting the surface (101a). A spectrofluorometer is used to measure the afterglow intensity of the phosphor doping coating of the substrate (101) material.

[0198] Regarding the numerical values (amounts, temperatures, etc.) used, efforts have been made to ensure accuracy, but some experimental errors and deviations should be considered.

[0199] One of ordinary skill in the art will recognize many methods and materials similar or equivalent to those described herein that can be used in practicing the subject matter described herein. The present disclosure is not limited to the methods and materials described in any sense.

[0200] When a range of values is specified, unless the context clearly indicates otherwise, each intervening value between the upper and lower limits of that range, down to one-tenth of the unit of the lower limit, and other recited values or intervening values within the recited range are understood to be included. Upper and lower limits of these smaller ranges that can be independently included in a smaller range are also included, depending on the upper and lower limits specifically excluded within the recited range. When one or both of the upper and lower limits of the recited range are included, ranges excluding one or both of them are also included.

[0201] Those of ordinary skill in the art to which this disclosure pertains, having the benefit of the teachings presented in the foregoing description and the associated drawings, will envision numerous modifications and other embodiments of the disclosure presented herein. Accordingly, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed, but that modifications and other embodiments are intended to be included within the scope of the claims. Furthermore, although the foregoing description and the accompanying drawings illustrate embodiments in the context of particular exemplary combinations of elements and / or functions, it is to be understood that alternative embodiments may provide different combinations of elements and / or functions without departing from the scope of the claims. In this regard, for example, different combinations of elements and / or functions, as may be shown in part in the claims, are envisioned that are different from those explicitly recited above. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. One or more types of inorganic phosphor dopants, Solvent, and Binder An ink composition containing the following:

2. The ink composition according to claim 1, wherein one or more inorganic phosphor dopants have a diameter of 0.5 μm or less.

3. One or more inorganic phosphor dopants, each independently, Pr ３＋ Ce ３＋ , Eu ３＋ , Eu ２＋ , Gd ３＋ , Tb ３＋ , and Dy ３＋ Selected from the group consisting of metal oxides and metal fluorides containing rare earth ions selected from the group consisting of or mixtures thereof, and optionally the rare earth ions are Pr ３＋ The ink composition according to claim 1 or 2, wherein the metal oxide is in either case selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof.

4. The ink composition according to claim 1, wherein the solvent is selected from the group consisting of water, methanol, ethanol, propanol, isopropyl alcohol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethyl sulfoxide, ethylene glycol ether, propylene glycol ether, ester, cyclohexanone, isophorone, and alkyl lactate.

5. The ink composition according to claim 1, wherein the binder is selected from the group consisting of ethylcellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane, polyvinyl alcohol, vinyl chloride / vinyl acetate copolymer, acrylic, and polyketone.

6. The ink composition according to claim 1, having a viscosity of about 2 mPa·s to about 30 mPa·s, and / or optionally formulated as an aerosol spray.

7. A method for preparing the ink composition described in claim 1, comprising contacting a solvent with one or more inorganic phosphor dopants and a binder, wherein the ink composition is prepared.

8. One or more types of inorganic phosphor dopants, One or more photopolymerization initiators, and One or more types of monomers A UV-curable ink composition containing [the specified ingredient].

9. The ultraviolet-curable ink composition according to claim 8, wherein one or more inorganic phosphor dopants have a diameter of 0.5 μm or less.

10. One or more inorganic phosphor dopants each independently contain Pr ３＋ , Ce ３＋ , Eu ３＋ , Eu ２＋ , Gd ３＋ , Tb ３＋ , and Dy ３＋ , or a rare earth ion selected from the group consisting of a mixture thereof, and is selected from the group consisting of metal oxides and metal fluorides, the ultraviolet curable ink composition according to claim 8 or 9.

11. Rare earth ions are Pr ３＋ The ultraviolet-curable ink composition according to claim 10.

12. The ultraviolet-curable ink composition according to claim 10, wherein the metal oxide is selected in any case from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof.

13. One or more photopolymerization initiators, each independently, include 4,4'-bis(dimethylamino)benzophenone, thioxanthene-9-one, 1-hydroxycyclohexylphenyl ketone, 2,4-dinitro-1-naphthol, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), azobisisobutyronitrile (AIBN), benzyldimethyl ketal (BDK, Irgacure 651), 2-hydroxymethyl-1-phenylpropane (Darocure 1173), hydroxycyclohexylphenyl ketone (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, monoacylphosphine oxide (Lucerin TPO), and Esacure. The ultraviolet-curable ink composition according to claim 8, selected from the group consisting of KIP150, monoacylphosphine oxide (MAPO), and bisacylphosphine oxide photopolymerization initiator (BAPO).

14. The ultraviolet-curable ink composition according to claim 8, wherein one or more monomers are each independently an acrylate monomer.

15. The ultraviolet-curable ink composition according to claim 8, further comprising one or more additives for reducing surface tension and / or improving the wettability of the substrate.

16. The ultraviolet-curable ink composition according to claim 8, having a viscosity of approximately 5 mPa·s to approximately 35 mPa·s.

17. A synthetic polymer including a surface, wherein the surface is coated with at least one coating of the ultraviolet-curable ink composition described in claim 8, the coating providing the synthetic polymer with improved color stability.

18. A method for preparing the ultraviolet-curable ink composition according to claim 8, comprising contacting one or more inorganic phosphor dopants with one or more photopolymerization initiators and one or more monomers, wherein the ultraviolet-curable ink composition is prepared.

19. An ink composition according to claim 1 or 8, wherein the ink composition has disinfectant properties upon exposure to an ultraviolet light source.

20. A method for improving the color stability of a synthetic polymer including a surface, wherein the surface is coated with the ink composition according to claim 1 or the ultraviolet-curable ink composition according to claim 8, the method comprising exposing the surface to ultraviolet light, wherein one or more inorganic phosphor dopants in the ink composition absorb the ultraviolet light and then emit the ultraviolet light as down-converted visible light.

Images