Phosphor-containing inks for disinfecting and improving light stability of synthetic polymers

Abstract

Described herein are phosphor-containing ink compositions for disinfecting surfaces and improving the light stability of synthetic polymers. Methods for preparing the ink compositions are also described.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to 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 contents of each of which are incorporated herein by reference in their entirety. Technical Field

[0003] The presently disclosed subject matter relates generally to phosphor-containing inks for disinfecting surfaces and improving the photostability of synthetic polymers. Background Art

[0004] Phosphor materials have the property of emitting ultraviolet, visible and infrared light by the action of external excitation means such as irradiation of electromagnetic waves (e.g., electron beams, X-rays, ultraviolet rays, visible light, etc.) or application of electric fields, and are therefore used in a large number of photoelectric transducers 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 are widely studied to meet the demand for low-voltage stimulated lighting sources due to the increased global energy consumption. Modern white light-emitting diodes (WLEDs) have replaced less efficient incandescent lamps and conventional fluorescent lighting sources containing mercury due to their environmental protection, long life, low energy consumption, reliability, and high luminous efficiency.

[0005] Lanthanides are often used as phosphors for luminescence applications. For example, the shielded f orbitals of praseodymium allow for long excited state lifetimes and high luminescence yields. In fact, Pr 3+ Typically a dopant ion for red, blue, green and ultraviolet phosphors. Summary of the invention

[0006] In one aspect, the presently disclosed subject matter is directed to an ink composition comprising one or more inorganic phosphor dopants, a solvent, and a binder.

[0007] In another aspect, the presently disclosed subject matter is directed to a UV-curable ink composition comprising one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers.

[0008] In another aspect, the presently disclosed subject matter is directed to an ink composition, wherein the ink composition has disinfecting properties when exposed to a UV light source.

[0009] In another aspect, the presently disclosed subject matter is directed to a synthetic polymer comprising a surface, wherein the surface is coated with a coating of the ink composition disclosed herein, and wherein the coating provides improved color stability to the synthetic polymer.

[0010] In another aspect, the presently disclosed subject matter is directed to a method for disinfecting a surface, wherein the surface is coated with an ink composition disclosed herein, the method comprising exposing the surface to a UV light source, wherein the exposure causes the one or more inorganic phosphor dopants in the ink composition to emit photons, and the photons irradiate the surface, thereby disinfecting the surface.

[0011] In another aspect, the presently disclosed subject matter relates to a method for improving the color stability of a synthetic polymer comprising a surface, wherein the surface is coated with an ink composition disclosed herein, the method comprising exposing the surface to UV light, wherein the one or more inorganic phosphor dopants in the ink composition absorb the UV light and then emit the UV light as down-converted visible light.

[0012] In another aspect, the presently disclosed subject matter is directed to a method of preparing 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, thereby preparing the ink composition.

[0013] In another aspect, the subject matter of the present disclosure relates to a method for preparing a UV-curable ink composition, the UV-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; thereby preparing the UV-curable ink composition.

[0014] These and other aspects are fully explained in this article.

[0015] The above summary of the invention is provided only for the purpose of summarizing some examples to provide a basic understanding of some aspects of the present invention. Therefore, it should be understood that the above examples are only examples and should not be interpreted as narrowing the scope or spirit of the present disclosure in any way. It should be understood that in addition to those examples summarized here, the scope of the present disclosure also covers many potential examples, some of which will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Having generally described certain examples of the present disclosure, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, in which:

[0017] Figure 1 A process for preparing an ink composition comprising one or more inorganic phosphor dopants according to the methods described herein is shown.

[0018] Figure 2A process for preparing a UV-curable ink composition containing one or more inorganic phosphor dopants according to the methods described herein is shown.

[0019] Figure 3 A process for disinfecting a surface by applying an ink composition according to the methods described herein is shown.

[0020] Figure 4 A process for creating a brighter appearance for an object by applying an ink composition according to the methods described herein is shown.

[0021] Figure 5 Exemplary excitation and emission spectra of inorganic phosphor dopants are shown.

[0022] Figure 6 It shows how white light can be produced by mixing blue, green and red emission.

[0023] Figure 7 Exemplary lattice structures of doped solid-state materials (ie, inorganic phosphor dopants) are shown. DETAILED DESCRIPTION

[0024] The subject matter described herein relates to ink compositions containing inorganic phosphors for disinfecting surfaces or improving the color stability of synthetic polymer compositions. The ink compositions that can be printed on various surfaces (such as but not limited to thermoplastics) utilize the luminescent properties of inorganic phosphor dopant materials.

[0025] disinfect

[0026] "Disinfection" refers to the reduction, inhibition, inactivation, destruction and / or elimination of microorganisms, except for bacterial endo-spores. The methods described herein provide multiple advantages over those methods of the prior art for disinfection. In fact, technical methods for disinfecting surfaces include the use of expensive and heavy ultraviolet light sources. Prolonged exposure to these light sources can affect the surface of the substrate. High-touch areas generally require long exposure to pulsed UV light. Other disinfection methods of the prior art include wiping the surface with a disinfectant solution that generally loses its effectiveness in a short period of time. In addition, exposure to such chemicals may have unintended effects on the surface of the substrate.

[0027] As described herein, incorporating an inorganic phosphor into an ink composition and then coating the ink composition on the surface of a substrate provides an emitting surface of UV-C light (200nm to 280nm) that can be used to disinfect the coated substrate surface over an extended period of time. After exposing the surface coated with the phosphor-containing ink to a UV excitation source, the ink coating emits photons within an adjustable time after the excitation light has been removed. The phosphor in the ink coating absorbs the UV light directly. The phosphor then emits radiant energy that disinfects the surface of the coated substrate. In this regard, the disinfection comes from the coated substrate surface itself. In addition, the disinfection method described herein is durable in operation because the inorganic phosphor is uniformly incorporated into the ink and coated on the surface of the substrate, which minimizes degradation caused by wear or exposure to surface chemicals. In addition, the ink composition coated on the surface of the substrate brings the inorganic phosphor closer to the surface than if the inorganic phosphor is embedded or otherwise incorporated into the substrate itself (e.g., a thermoplastic substrate). The disinfection method described herein can significantly reduce the time required to disinfect a surface using conventional methods.

[0028] UV-C light is weak at the Earth's surface because the atmosphere's ozone layer blocks it. Many disinfection methods use short-wavelength ultraviolet (ultraviolet C or UV-C) light to kill or inactivate microorganisms by damaging nucleic acids and interfering with their DNA, rendering them unable to perform important cellular functions. The inorganic phosphors in the phosphor-containing ink compositions described herein emit this germicidal UV-C light, which acts to disinfect the surface to which the ink is applied.

[0029] Color stability

[0030] When exposed to UV light in the presence of oxygen, synthetic polymers (such as thermoplastics) will generally undergo photooxidation. When the polymer absorbs the UV radiation energy, it can cause bond breakage because the energy of the UV light is greater than the dissociation energy of the carbon-carbon sigma bond in the synthetic polymer. In fact, UV light has a photon energy of 6.2eV to 4.4eV. In contrast, the bond energy of a typical carbon-carbon sigma bond is only 3.8eV. Thus, absorption of UV light (such as UV-C light) in the presence of oxygen can lead to bond dissociation oxidation, which results in changes in the molecular structure of the polymer. Such structural changes are often accompanied by undesirable significant physical changes in the polymer, such as discoloration (yellowing) and embrittlement.

[0031] Current solutions to the discoloration and embrittlement often experienced by synthetic polymers exposed to UV light include: (1) using polymers with higher color stability in applications where there is high UV light exposure; and / or (2) incorporating UV stabilizing additives into synthetic polymer formulations. However, synthetic polymers that exhibit satisfactory color stability may lack appropriate mechanical properties, such as impact durability and chemical resistance. In addition, additives used to improve color stability in synthetic polymers often reduce the mechanical properties of the material, such as tensile strength. These additives have also been shown to reduce the flammability of the material. Therefore, there is a need in the art to stabilize the color of synthetic polymers exposed to UV light without reducing other material performance properties.

[0032] Exemplary embodiments of the subject matter described herein overcome the limitations of the prior art by incorporating an inorganic phosphor into an ink composition and coating the ink composition on the surface of a synthetic polymer. The inorganic phosphor in the ink absorbs UV light and converts it into harmless visible light. The inorganic phosphor used in the methods and ink compositions described herein is a crystalline material having a lattice structure that imparts high photostability, such as Figure 7 As shown in the exemplary lattice structure of . For example, the regular rigid arrangement of atoms in the lattice gives the phosphor enhanced thermal stability. In these phosphors, a small percentage of metal "dopant" ions are incorporated into the lattice, which will affect the excitation and emission properties of the phosphor. As used herein, inorganic phosphor dopants refer to metal oxides or metal fluoride materials containing rare earth or transition metals. Since the inorganic phosphor material is a ceramic-type material that only coats the surface of the synthetic polymer, it has no adverse effect on the mechanical properties or flammability of the synthetic polymer material. Many phosphors strongly absorb (high energy; short wavelength) UV light, accompanied by the emission of light with longer wavelengths and lower energy than the light initially absorbed by the phosphor. This emission is usually in the visible light range, which is not destructive to synthetic polymers. The process of light absorption at one wavelength followed by emission at a longer wavelength is called "down conversion". The inorganic phosphors in the ink composition described herein absorb high energy UV light (180nm-360nm) and emit the energy as "down-converted" visible light (200nm-700nm), such as Figure 5 Exemplary excitation and emission spectra are shown in .

[0033] As described herein, the color of the emitted light energy can be customized by incorporating different metal ions into the metal oxide or metal fluoride host lattice. Combinations of different emission colors will produce white / off-white light. For example, a blue-yellow or blue-green-red emitter combination provides white / off-white emission. This combination of light emission from phosphors can be used to customize the visual color of solids.

[0034] Exemplary embodiments of the subject matter described herein manage the effects of UV light on synthetic polymers by selectively incorporating an inorganic phosphor into an ink composition that coats the synthetic polymer surface. The inorganic phosphor in the ink composition absorbs and down-converts visible light, thereby providing a brighter appearance to the synthetic polymer material. The brighter appearance is the brightness perceived by a viewer.

[0035] The subject matter of the present disclosure will now be described more fully below. However, a person skilled in the art of the subject matter of the present disclosure, who has benefited from the teachings presented in the foregoing description, will think of many modifications and other examples of the subject matter of the present disclosure set forth herein. Therefore, it should be understood that the subject matter of the present disclosure is not limited to the specific examples disclosed, and modifications and other examples should be included within the scope of the appended claims. In other words, the subject matter described herein encompasses all substitutions, modifications and equivalents. In fact, according to the various embodiments described herein, such determined disinfection properties and improved light stability are not limited to the ink containing the phosphor used in inkjet printing. As will be understood by a person of ordinary skill in the art based on the present disclosure, such disinfection properties and improved light stability can be used in various applications other than inkjet printing or even ink compositions. In fact, it is usually more convenient or more desirable for a manufacturer to be able to coat a substrate that the manufacturer has already manufactured (rather than, for example, redesigning the material used to manufacture such a substrate) so as to embed such an inorganic phosphor into the material to impart the desired function. For example, in the case where colorant particles are traditionally used to impart color to a surface, at least a portion of the colorant can be replaced with an inorganic phosphor capable of emitting germicidal radiation to alternatively impart antimicrobial / antipathogen functionality (instead of color) to the surface. In fact, the benefits of the phosphor-containing compositions of the present disclosure are not limited to printing applications, as the compositions can be adjusted to be applied via any number of coating techniques (e.g., dipping, spraying / aerosolization, roller coating, or brush application) depending on industrial and / or manufacturing needs. One of ordinary skill in the art will appreciate that because the inorganic phosphor will be present in relatively small amounts compared to the colorant loading of the colored coating, the formulation can be modified and / or rebalanced to support this application in order to produce a stable liquid that is compatible with the application tool (e.g., a paint spray gun, inkjet print head, etc.).

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those of ordinary skill in the art generally understood. All publications, patent applications, patents and other references mentioned herein are incorporated herein by reference in their entirety. In the case where one or more of the documents, patents and similar materials incorporated therein are different or contradictory from the present application (including but not limited to defined terms, term usage, described technology, etc.), the present application shall prevail.

[0037] I. Definitions

[0038] As used herein, "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 when interpreted in the alternative ("or").

[0039] As used herein, the terms "approximately," "about," "substantially," and "substantially" refer to an amount that is close to a stated amount and still performs a desired function or achieves a desired result. For example, in some instances, as the context may dictate, the terms "approximately," "about," and "substantially" may refer to an amount that is within less than or equal to 10% of a stated amount. As used herein, the term "generally" refers to a value, amount, or characteristic that primarily includes or tends toward a particular value, amount, or characteristic.

[0040] As used herein, conditional language, such as "can", "may", "possibly", "could", "for example", etc., unless otherwise specifically stated or otherwise understood in the context of use, is generally intended to convey that certain instances include (while other instances do not include) certain features, elements, and / or steps. Therefore, such conditional language is generally not intended to imply that one or more instances require features, elements, and / or steps in any way, or that one or more instances must include logic for determining whether these features, elements, and / or steps are included or will be performed in any particular instance with or without author input or prompting. The terms "comprising", "including", "having", etc. are synonymous and are used inclusively in an open-ended manner and do not exclude additional elements, features, actions, operations, etc. The terms "consisting of" and "composed of", etc. are synonymous and used in a closed manner and do not exclude additional elements, features, actions, operations, etc. The terms "consisting essentially of" and "consisting essentially of", etc. are synonymous semi-closed terms that indicate that the items in the claim are limited to the components specified in the claim and those components that do not materially affect the basic and novel characteristics of the claim. Additionally, the term "or" is used in its inclusive sense (rather than in its exclusive sense) such that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list.

[0041] As used herein, "contacting" refers to contacting a solvent with one or more inorganic phosphor dopants and a binder to prepare an ink composition, or contacting one or more inorganic phosphor dopants with one or more photoinitiators and one or more monomers to prepare a UV curable ink composition. In certain examples, contacting can be assisted by, for example, applying heat and / or pressure.

[0042] As used herein, a "coated surface" or a "coated" surface refers to a surface that has been treated with an ink composition disclosed herein and contains at least one layer of the ink composition on its surface. In some examples, the coated surface includes only one layer of the ink composition disclosed herein. In other examples, the coated surface refers to multiple layers of the ink composition disclosed herein on the surface of a substrate. As a non-limiting example, a first layer (e.g., an inner layer) of an ink composition may be applied to the surface of a substrate, followed by one or more additional layers (e.g., an outer layer) of an ink composition applied to the first layer. In other examples, one or more inner layers in such a multi-layer coated surface may not be exposed to UV light (e.g., activated) unless and until the outer layer of the ink composition is exposed to UV light, causing the outer layer itself to emit light. The one or more inorganic phosphor dopants in such an inner layer may emit light of a longer wavelength compared to the outer layer. In some examples, the one or more inorganic phosphor dopants in such an inner layer may emit light of a longer wavelength after absorbing light emitted by the outer layer. In other examples, the ink composition layer on the surface of the coated surface may have a varying thickness. In some examples, the coated surface and one or more layers of the ink composition forming the coated surface may be continuous. In other examples, the coated surface and at least one layer of the ink composition forming the coated surface may be discontinuous.

[0043] As used herein, "improving color stability" refers to extending the color life of a synthetic polymer material and / or reducing the occurrence of yellowing of a synthetic polymer host material due to exposure to UV light, compared to a polymer material that does not include 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 a synthetic polymer surface. The one or more inorganic phosphor dopants in the ink coating can absorb UV light, thereby reducing the effects of UV absorption on the color stability of the polymer. In an example, the inorganic phosphor dopant absorbs more incident UV light than the synthetic polymer material below the ink composition, thereby counteracting photo-oxidation and discoloration of the polymer material.

[0044] This improved color stability can be measured visually 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 subjecting both the control synthetic polymer and the test synthetic polymer to UV exposure. The color change can be easily perceived by comparing the amount of any color change between the control sample and the test sample. For example, if a synthetic polymer that has been coated with the ink composition described herein exhibits no or significantly less yellowing compared to the control sample that was also subjected to UV exposure, it is said to have improved color stability.

[0045] Additionally, different phosphors can be mixed in the ink composition to emit white or off-white visible light, thereby creating a brighter appearance for the polymer material. The concept of creating white light by mixing phosphors that emit light of different wavelengths is similar to what is observed when using LEDs to create white light, such as Figure 6 For example, a conventional white light source can be achieved by mixing red light, green light, and blue light at a suitable intensity ratio. Alternatively, a white light source can be achieved by mixing yellow light and blue light at a suitable intensity ratio. Examples of selecting phosphors and incorporating them into ink compositions to emit light of different colors, which then combine to produce white light, are provided herein.

[0046] As used herein, "white light" refers to the combination of all wavelengths of electromagnetic radiation in the visible range of the spectrum, wherein each wavelength is present in equal amounts relative to the other wavelengths. "Off-white" light refers to a combination of wavelengths in the visible range of electromagnetic radiation that is, for example, close to white light but not present in equal amounts.

[0047] As used herein, "photo-oxidation" refers to the degradation of polymer surfaces due to the combined action of light and oxygen. Photo-oxidation causes polymer chain scission, resulting in the material becoming increasingly brittle.

[0048] As used herein, the terms "inorganic phosphor dopant" and "phosphor" are used interchangeably.

[0049] As used herein, a "UV curable" ink composition refers to an ink formulation comprising one or more inorganic phosphor dopants, one or more photoinitiators, and one or more monomers that dries or hardens when exposed to ultraviolet light.

[0050] II. Ink Composition

[0051] A. In certain examples, 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).

[0052] In certain examples of the above-mentioned ink composition (110), the one or more inorganic phosphor dopants (100) have a diameter of no greater than 0.5 μm, so that the ink composition (110) is compatible with the print head and can pass through the print head, such as printing on the surface (101a) of the substrate (101). In certain other examples, the one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in certain other examples, the 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 examples, the diameter of the one or more inorganic phosphor dopants (100) is 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, m, 0.24μm, 0.25μm, 0.26μm, 0.27μm, 0.28μm, 0.29μm, 0.30μm, 0.31μm, 0.32μm, 0.33μm, 0.34μm, 0.35μm, 0.36μm, 0. 37μm, 0.38μm, 0.39μm, 0.40μm, 0.41μm, 0.42μm, 0.43μm, 0.44μm, 0.45μm, 0.46μm, 0.47μm, 0.48μm, 0.49μm and 0.50μm. The size of the inorganic phosphor dopant (100) can be measured using, for example, 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").

[0053] In certain examples of the above-mentioned ink composition (110), the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 to 75 weight % in order to obtain the correct optical density according to the application of the ink composition (110). In certain other examples, including but not limited to the ink composition (110) being formulated as a graphic inkjet ink composition, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 to 50 weight %, about 1 to 25 weight %, about 1 to 15 weight %, about 1 to 10 weight %, about 1 to 5 weight %, about 1 to 3 weight % or about 1 to 2 weight %. In certain other examples, including but not limited to the ink composition (110) being formulated as a non-graphic ink composition, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 50 to 75 weight %, about 55 to 70 weight % or about 60 to 65 weight %. In some examples, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% and 75 wt%.

[0054] In certain examples of the above-described ink composition (110), the one or more inorganic phosphor dopants (100) are capable of emitting photons (105) having a wavelength of light of about 200 nm to 280 nm, 200 nm to 270 nm, about 200 nm to 250 nm, about 225 nm to 250 nm, about 200 nm to 225 nm, about 200 nm to 275 nm, or about 225 nm to 275 nm when exposed to a UV light source (104).

[0055] In certain examples of the ink composition (110), the one or more inorganic phosphor dopants (100) are each independently selected from the group consisting of metal oxides (106) and metal fluorides (108) containing rare earth ions (107), wherein the rare earth ions (107) are 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 certain embodiments of the ink composition (110), the rare earth ion (107) is Pr +3In some examples of the ink composition (110), the metal oxides (106) are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof. In some examples, the silicates are selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates, and orthosilicates. Non-limiting examples of silicates include Sr 2 MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl 2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10 SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi 2 O 2 N 2 , where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 )2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O 12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca 2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is doped with Pr 3+ Ca 2 Al 2 SiO 7 .

[0056] In certain examples of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from Cs 2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4 Such metal fluoride (108) hosts are generally characterized by having large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful in inorganic phosphors. In certain examples, the one or more inorganic phosphor dopants (100) are doped with Pr 3+ Cs 2 NeA 6 (Cs 2 NeA 6:Pr 3+ ). In the example, Pr 3+ Substitute Cs in an amount of about 0.3% to about 10% 2 NeA 6 In other examples, Pr 3+ Substituting Cs in an amount of about 1% to 5%, 1.5% to 4.5%, 2.5% to 5%, 2% to 7%, 3% to 8%, or 4% to 9%. 2 NeA 6 Yttrium ion sites in .

[0057] In some examples of the above-mentioned ink composition (110), the solvent (111) is selected from but not limited to alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, polyols, ethylene glycol, glycerol and PEG, etc.), ketones and ketone alcohols (e.g., acetone and diacetone alcohol, etc.), ethers (e.g., tetrahydrofuran, dioxane and alkyl ethers, etc.), ethers of polyols (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether), nitrogen-containing solvents (e.g., 2-pyrrolidone and N-methyl-2-pyrrolidone, etc.), sulfur-containing solvents (e.g., 2,2'-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone and cyclopentane sulfone, etc.) and sugars and their derivatives (e.g., glucose, ethylene oxide adducts of glycerol and ethylene oxide adducts of diglycerol, etc.). In certain examples of the above ink composition (110), the solvent (111) is selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone and dimethyl sulfoxide. In certain examples, the solvent (111) is water. In certain other examples, the solvent (111) comprises water and one or more co-solvents, which may be water-soluble, water-miscible or a combination thereof. Such solvents (111) may be used to affect the fluidity of the ink composition (110). For example, in some examples, if the flow of the ink composition (110) would otherwise be insufficient, it is desirable to use a solvent (111) to increase the flow of the ink composition (110).

[0058] In some examples of the ink composition (110) described above, the binder (112) is a water-soluble or alcohol-soluble binder. In some examples, the binder (112) is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane and polyvinyl alcohol. In some examples of the above method, the binder (112) is cured by evaporation. In some examples, the binder (112) has a molecular weight of less than 100,000 and typically less than 50,000. In some examples, the binder (112) comprises one or more of vinyl chloride / vinyl acetate copolymers, acrylics and polyketones.

[0059] In some examples of the ink composition (110) described above, the ink composition (110) has a viscosity of about 2 mPa-s to about 30 mPa-s, so as to impart sufficient fluidity to the ink composition (110). In some examples, the viscosity of the ink composition (110) is 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.

[0060] In some examples of the ink composition (110) described above, the ink composition (110) is formulated as a coating. In some other examples of the ink composition (110) described above, the ink composition (110) is formulated as a varnish or a filler. In some other examples of the ink composition (110) described above, the ink composition (110) is formulated as an aerosol spray. In some other examples of the ink composition (110) described above, the ink composition (110) is formulated for rotary screen printing.

[0061] The preferred amounts and relative ratios of the components (inorganic phosphor dopant (100); solvent (111); and binder (112)) of the ink composition (110) will vary widely based on the intended application of the ink composition (110). For example, in a rotary screen printing process, manufacturers require that the ink composition (110) be a non-Newtonian fluid and exhibit high viscosity, properties that would be incompatible with an inkjet printer.

[0062] B. In certain examples, the subject matter described herein relates to a UV curable ink composition (113) comprising one or more inorganic phosphor dopants (100), one or more photoinitiators (114), and one or more monomers (115).

[0063] The UV curable ink composition (113) of the present application is compatible with a wide variety of substrates (101) and enables easy maintenance of the print head because the UV curable ink composition (113) will not cure before reacting with the correct UV light dose or wavelength. The UV curable ink composition (113) of the present application has good durability and is environmentally friendly because it has near zero VOC. The UV curable ink composition (113) of the present application also enables control of the thickness of the film layer applied (i.e., can be accumulated by additive printing technology).

[0064] In certain examples of the UV curable ink composition (113), the one or more inorganic phosphor dopants (100) have a diameter of no greater than 0.5 μm, so that the ink composition (110) is compatible with a print head and can pass through the print head, such as printing on the surface (101a) of the substrate (101). In certain other examples, the one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in certain other examples, the 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 examples, the diameter of the one or more inorganic phosphor dopants (100) is 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, m, 0.24μm, 0.25μm, 0.26μm, 0.27μm, 0.28μm, 0.29μm, 0.30μm, 0.31μm, 0.32μm, 0.33μm, 0.34μm, 0.35μm, 0.36μm, 0. 37μm, 0.38μm, 0.39μm, 0.40μm, 0.41μm, 0.42μm, 0.43μm, 0.44μm, 0.45μm, 0.46μm, 0.47μm, 0.48μm, 0.49μm and 0.50μm. The size of the inorganic phosphor dopant (100) can be measured using, for example, 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”).

[0065] In certain examples of the above-mentioned UV curable ink composition (113), the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 to 75 weight % in order to obtain the correct optical density according to the application of the UV curable ink composition (113). In certain other examples, including but not limited to the UV curable ink composition (113) being formulated as a graphic inkjet ink composition, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 to 50 weight %, about 1 to 25 weight %, about 1 to 15 weight %, about 1 to 10 weight %, about 1 to 5 weight %, about 1 to 3 weight % or about 1 to 2 weight %. In certain other examples, including but not limited to the UV curable ink composition (113) being formulated as a non-graphic ink composition, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 50 to 75 wt%, about 55 to 70 wt%, or about 60 to 65 wt%. In certain examples, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%.

[0066] In certain examples of the above-mentioned UV curable ink composition (113), the one or more inorganic phosphor dopants (100) are capable of emitting photons (105) having a light wavelength of about 200nm to 280nm, 200nm to 270nm, about 200nm to 250nm, about 225nm to 250nm, about 200nm to 225nm, about 200nm to 275nm, or about 225nm to 275nm when exposed to a UV light source (104).

[0067] In certain examples of the UV curable ink composition (113), the one or more inorganic phosphor dopants (100) are each independently selected from the group consisting of metal oxides (106) and metal fluorides (108) containing rare earth ions (107), wherein the rare earth ions are selected from the group consisting of Pr 3+ 、Ce 3+ 、Eu 3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+In certain embodiments of the UV curable ink composition (113), the rare earth ion (107) is Pr +3 In certain examples of the UV curable ink composition (113), the metal oxides (106) are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates or combinations thereof. In certain examples, the silicates are selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates and orthosilicates. Non-limiting examples of silicates include Sr 2 MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl 2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10 SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi 2 O 2 N 2, where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 ) 2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O 12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca 2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is doped with Pr 3+ Ca 2 Al 2 SiO 7 .

[0068] In certain examples of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from Cs 2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4 Such metal fluoride (108) hosts are generally characterized by having large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful in inorganic phosphors. In certain examples, the one or more inorganic phosphor dopants (100) are doped with Pr3+ Cs 2 NeA 6 (Cs 2 NeA 6 :Pr 3+ ). In the example, Pr 3+ Substitute Cs in an amount of about 0.3% to about 10% 2 NeA 6 In other examples, Pr 3+ Substituting Cs in an amount of about 1% to 5%, 1.5% to 4.5%, 2.5% to 5%, 2% to 7%, 3% to 8%, or 4% to 9%. 2 NeA 6 Yttrium ion sites in .

[0069] In certain examples of the above-mentioned UV curable ink composition (113), the one or more photoinitiators (114) 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 and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO).

[0070] In certain examples of the above-mentioned UV curable ink composition (113), the one or more monomers (115) are each independently an acrylate monomer. In certain examples of the UV curable ink composition (113), the one or more monomers (115) are each independently 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), 1,3-butanediol diacrylate, di(trimethylolpropane) tetraacrylate, hexanediol diacrylate, ethoxy(3) cyclohexanol and / or dimethanol diacrylate. Such acrylate monomers (115) can be used as a binder (112) to improve one or more properties of the UV curable ink composition (113), such as pigment dispersion, adhesion, chemical resistance, mechanical resistance, UV resistance, etc. For example, in certain instances of the above method where little or no odor is desired, suitable acrylate monomers (115) may 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 cyclotrimethylolpropane formal acrylate (12 mPas at 25°C).

[0071] In certain instances of the above method where moderate to high flexibility is required (e.g., to apply a printed film on a wavy surface (101a) and resist cracking), suitable acrylate monomers (115) may 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) (higher degree of ethoxylation up to 15 (EO); higher flexibility, less odor).

[0072] In certain other examples of the above methods where moderate hardness is desired (eg, to resist abrasion, scratching, and marring), suitable acrylate monomers (115) may include tricyclodecane dimethanol diacrylate (120 mPas at 25°C).

[0073] In certain other examples of the above methods where moderate toughness is required (e.g., to resist breakage due to impact), suitable acrylate monomers (115) may include isobornyl acrylate (10 mPas at 25°C) (very tough), isohexyl acrylate (6 mPas at 25°C) (high impact strength), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25°C), dioxanediol 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).

[0074] In certain other examples of the above methods where good adhesion (e.g., resistance to removal from various substrates) is desired, suitable acrylate monomers (115) may include diethylene glycol butyl ether acrylate (5 mPas at 25° C.), 2(2-ethoxyethoxy)ethyl acrylate (5 mPas at 25° C.), tetrahydrofuranyl acrylate (5 mPas at 25° C.), isobornyl acrylate (10 mPas at 25° C.), cyclotrimethylolpropane formal ... Acrylates (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) (high versatility), dioxanediol diacrylate (25°C, 250 mPas) and / or propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25°C).

[0075] In certain other examples of the above methods where good wetting is desired (e.g., to form 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 wetting) and / or propoxylated (3) trimethylolpropane triacrylate (100 mPas at 25°C).

[0076] In certain other examples of the above methods, the acrylate monomer (115) can be selected to impart sufficiently low viscosity (e.g., to enable jetting from a piezo head; tentatively, 25 cP at 25-45°C) and / or chemical resistance (e.g., to withstand degradation due to exposure to any number of commercially available surface cleaners and disinfectants that might be used, for example, by airline operators).

[0077] In some examples of the UV curable ink composition (113) described above, the UV curable ink composition (113) further comprises one or more additives for reducing surface tension and / or improving substrate wetting. By reducing surface tension, properties such as droplet formation and substrate wetting can be improved. In some examples of the UV curable ink composition (113) described above, the one or more additives are selected from the group consisting of alkoxylated, silicone, silicone-acrylated surfactants and fluorocarbons.

[0078] In some examples of the UV curable ink composition (113) described above, the UV curable ink composition (113) has a viscosity of about 5 mPa-s to about 35 mPa-s. In some examples, the viscosity of the UV curable ink composition (113) is 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.

[0079] In some examples of the UV curable ink composition (113), the UV curable ink composition (113) is formulated as a coating. In some other examples of the UV curable ink composition (113), the UV curable ink composition (113) is formulated as a dip varnish or a filler. In some other examples of the UV curable ink composition (113), the UV curable ink composition (113) is formulated as an aerosol spray. In some other examples of the UV curable ink composition (113), the UV curable ink composition (113) is formulated for rotary screen printing.

[0080] The preferred amounts and relative ratios of the components (inorganic phosphor dopant (100), photoinitiator (114) and monomer (115)) of the UV curable ink composition (113) will vary widely depending on the intended application of the UV curable ink composition (113). For example, in a rotary screen printing process, manufacturers require that the UV curable ink composition (113) be a non-Newtonian fluid and exhibit a high viscosity, properties that would be incompatible with an inkjet printer.

[0081] III. Method for Preparing Ink Composition

[0082] 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 metal oxide (106) host material and a rare earth oxide are weighed so that a certain amount of 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 suggested stoichiometry of the material and then weighing an appropriate amount of the raw material using dimensional analysis. The metal oxide (106) powder is thoroughly ground using a mortar and pestle to maximize contact between particles in the mixture. After being placed in a suitable crucible (usually alumina), the mixture is heated in a tubular or muffle furnace to a temperature sufficient to cause a solid-state reaction but below the melting temperature of the final compound. From temperatures of about 200° C. below this melting temperature, the grain size of the final compound increases strongly. This heating process is known as sintering, which generally leads to very dense and firmly agglomerated materials. Such materials cannot be used directly as phosphors. Therefore, post-synthesis grinding is usually necessary, either manually or using a ball mill.

[0083] Ball milling is a mechanical process that reduces particle size by mechanical impact and friction. Typically, a powder is milled against a number of hard grinding balls (usually Al 2 O 3 or ZrO 2 ) and a solvent are placed in a grinding jar to obtain a slurry. The grinding jar is then moved so as to achieve maximum friction. Similar to manual grinding using a mortar and pestle, the effectiveness of this process is highly dependent on the size and hardness of the raw materials.

[0084] For the above solid-state synthesis, the atmosphere used for heating may vary depending on the host material. In the case of oxides, air may generally be applied. However, some dopants, particularly europium, may oxidize in the oxygen lattice while being heated in oxygen, resulting in the formation of fully oxidized Eu 3+ Dopant. If Eu 2+ is the preferred valence state of the dopant, additional heat treatment in a reducing atmosphere such as helium or argon may be required.

[0085] Other methods for preparing the inorganic phosphor dopant (100) include sol-gel synthesis, colloidal synthesis, and coprecipitation. For example, in the sol-gel process, the powder is weighed and dissolved in a concentrated acid, such as HNO 3 (e.g. 70 wt %), and then diluted with deionized water. The solution can then be cooled to room temperature and added dropwise to a cold saturated aqueous solution of another acid (e.g. oxalic acid). The solid material is then precipitated and then washed with deionized water and other polar solvents (e.g. acetone, acetonitrile, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), isopropanol or methanol). The solid material will then undergo calcination at a temperature of about 1000° C. to 1200° C. for several hours, followed by intermittent grinding and sintering. In some instances, 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.

[0086] like Figure 1 and 2 As shown, for example, after one or more inorganic phosphor dopants (100) are prepared, they are then used to formulate an ink composition (110) and / or a UV curable ink composition (113), as described below.

[0087] A. In certain examples, the subject matter described herein relates to a method of preparing an ink composition (110), the ink composition comprising: one or more inorganic phosphor dopants (100); a solvent (111); and a binder (112), the method comprising: preparing the one or more inorganic phosphor dopants (100) in step 150; and contacting the solvent (111) with the one or more inorganic phosphor dopants (100) and the binder (112) in step 155 to prepare the ink composition (110), such as Figure 1 As shown further.

[0088] In certain examples of the above method, the one or more inorganic phosphor dopants (100) have a diameter of no greater than 0.5 μm, so that the ink composition (110) is compatible with the print head and can pass through the print head, such as printing on the surface (101a) of the substrate (101). In certain other examples, the one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in certain other examples of the above method, the one or more inorganic phosphor dopants (100) have a diameter of about 0.01 to 0.5 μm, about 0.05 to 0.45 μm, about 0.10 to 0.3 μm, about 0.2 to 0.5 μm, about 0.4 to 0.5 μm, about 0.01 to 0.2 μm, about 0.2 to 0.3 μm, or about 0.35 to 0.45 μm. In some examples, the diameter of the one or more inorganic phosphor dopants (100) is 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, m, 0.24μm, 0.25μm, 0.26μm, 0.27μm, 0.28μm, 0.29μm, 0.30μm, 0.31μm, 0.32μm, 0.33μm, 0.34μm, 0.35μm, 0.36μm, 0. 37μm, 0.38μm, 0.39μm, 0.40μm, 0.41μm, 0.42μm, 0.43μm, 0.44μm, 0.45μm, 0.46μm, 0.47μm, 0.48μm, 0.49μm and 0.50μm. The size of the inorganic phosphor dopant (100) can be measured using, for example, 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”).

[0089] In certain examples of the above methods, the one or more inorganic phosphor dopants (100) are capable of emitting photons (105) having a wavelength of light of about 200nm to 280nm, 200nm to 270nm, about 200nm to 250nm, about 225nm to 250nm, about 200nm to 225nm, about 200nm to 275nm, or about 225nm to 275nm when exposed to a UV light source (104).

[0090] In certain examples of the above method, the one or more inorganic phosphor dopants (100) are each independently selected from the group consisting of metal oxides (106) and metal fluorides (108) containing rare earth ions (107), wherein the rare earth ions are 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 certain embodiments of the above method, the rare earth ion (107) is Pr +3 In some examples of the above method, the metal oxides (106) are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates or combinations thereof. In some examples, the silicate is selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates and orthosilicates. Non-limiting examples of silicates include Sr 2 MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl 2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi 2 O 2 N 2 , where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 ) 2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O 12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca 2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is doped with Pr 3+ Ca 2 Al 2 SiO 7 .

[0091] In certain examples of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from Cs2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4 Such metal fluoride (108) hosts are generally characterized by having large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful in inorganic phosphors. In certain examples, the one or more inorganic phosphor dopants (100) are doped with Pr 3+ Cs 2 NeA 6 (Cs 2 NeA 6 :Pr 3+ ). In the example, Pr 3+ Substitute Cs in an amount of about 0.3% to about 10% 2 NeA 6 In other examples, Pr 3+ Substituting Cs in an amount of about 1% to 5%, 1.5% to 4.5%, 2.5% to 5%, 2% to 7%, 3% to 8%, or 4% to 9%. 2 NeA 6 Yttrium ion sites in .

[0092] In certain examples of the above method, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 to 75 weight % in order to obtain the correct optical density according to the application of the ink composition (110). In certain other examples, including but not limited to the ink composition (110) being formulated as a graphic inkjet ink composition, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 to 50 weight %, about 1 to 25 weight %, about 1 to 15 weight %, about 1 to 10 weight %, about 1 to 5 weight %, about 1 to 3 weight %, or about 1 to 2 weight %. In certain other examples, including but not limited to the ink composition (110) being formulated as a non-graphic ink composition, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 50 to 75 weight %, about 55 to 70 weight %, or about 60 to 65 weight %. In some examples, the one or more inorganic phosphor dopants (100) are present in the ink composition (110) at about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% and 75 wt%.

[0093] Some suitable solvents are described in, for example, S. Magdassi, Chemistry of Inkjet Inks (2009). In some examples of the above method, the solvent (111) is selected from but not limited to alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, polyols, ethylene glycol, glycerol and PEG, etc.), ketones and ketone alcohols (e.g., acetone and diacetone alcohol, as well as cyclohexanone and isophorone with higher boiling points, etc.), ethers (e.g., tetrahydrofuran, dioxane and alkyl ethers, etc.), ethers of polyols (e.g., ethylene glycol ether, propylene glycol ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether), nitrogen-containing solvents (e.g., 2-pyrrolidone and N-methyl-2-pyrrolidone, etc.), esters of these ethers, sulfur-containing solvents (e.g., 2,2'-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone and cyclopentane sulfone, etc.), alkyl lactates, sugars and their derivatives (e.g., glucose, ethylene oxide adducts of glycerol and ethylene oxide adducts of diglycerol, etc.). In certain examples of the above ink composition (110), the solvent (111) is selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone and dimethyl sulfoxide. In certain examples, the solvent (111) is water. In certain other examples, the solvent (111) includes water and one or more co-solvents, which may be water-soluble, water-miscible or a combination thereof. For the ink composition (110) formulated for inkjet printing, a solvent (111) or a blend of solvents (111) is desired, whereby the ink composition (110) dries quickly enough after printing onto the substrate (101), but not so fast that the ink dries in the print head nozzle. According to S. Magdassi, the solvent (111) typically has a moderate (0.8-3) or slow (<0.3 on a scale of n-butyl acetate=1) evaporation rate.

[0094] In certain examples, the one or more solvents (111) are preferably present in the ink composition (110) at about 1 to 99 weight percent. When a mixture of solvents (111) is used, the mixture can contain any suitable proportion of the 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 examples, if 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 certain other examples, including but not limited to ink compositions (110) formulated for inkjet printing, the one or more solvents (111) are present in the ink composition (110) at 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 certain other examples, including but not limited to ink compositions (110) formulated as non-graphic ink compositions, the one or more solvents (111) are present in the ink composition (110) at about 25 to 50 wt%, about 30 to 45 wt%, or about 35 to 40 wt%. In certain examples, the one or more solvents (111) are present in the ink composition (110) at about 10 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 98 wt%, and 99 wt%. In certain examples of the above methods, the ink composition (110) has a viscosity of about 2 mPa-s to about 30 mPa-s. In some examples, the viscosity of the ink composition (110) is 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.

[0095] In some examples of the above method, the binder (112) is a water-soluble or alcohol-soluble binder. In some examples, the binder (112) is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane and polyvinyl alcohol. In some other examples, acrylates of different functionalities and proportions are used to form the binder (112). In some examples of the above ink composition (110), the binder (112) is an important component that affects the film properties of applications such as aircraft wallpaper graphics and protective varnishes. In some examples of the above method, the binder (112) is cured by evaporation. In some examples, the binder (112) is responsible for retaining and bonding the pigment and / or inorganic phosphor dopant (100) to the surface (101a) after the ink composition (110) is printed, coated or otherwise applied to the surface (101a) and cured.

[0096] In certain examples, the one or more binders (112) are preferably present in the ink composition (110) at about 1 to 25 weight percent. When a mixture of binders (112) is used, the mixture can contain any suitable ratio of binders (112). In certain examples, the one or more binders (112) are present in the ink composition (110) at about 5 to 25 weight percent, 10 to 20 weight percent, or about 15 to 18 weight percent. In certain examples, the one or more binders (112) are present in the ink composition (110) at about 1 weight percent, 3 weight percent, 5 weight percent, 10 weight percent, 15 weight percent, 18 weight percent, 20 weight percent, and 25 weight percent.

[0097] In certain examples, a solvent (111) is contacted with the one or more prepared inorganic phosphor dopants (100) and a binder (112). In certain examples of the above method, the one or more inorganic phosphor dopants (100) are in powder form and are combined with the solvent (111) and the binder (112). The one or more inorganic phosphor dopants (100), the solvent (111) and the binder (112) are then mixed to form an ink composition (110).

[0098] B. In certain examples, the subject matter described herein relates to a method for preparing a UV-curable ink composition (113), the UV-curable ink composition comprising: one or more inorganic phosphor dopants (100); one or more photoinitiators (114); and one or more monomers (115), the method comprising: preparing the one or more inorganic phosphor dopants (100) in step 250; and contacting the one or more inorganic phosphor dopants (100) with the one or more photoinitiators (114) and the one or more monomers (115) in step 255 to prepare the UV-curable ink composition (113), such as Figure 2 As shown further.

[0099] In certain examples of the above method, the one or more inorganic phosphor dopants (100) have a diameter of no greater than 0.5 μm, so that the UV curable ink composition (113) is compatible with the print head and can pass through the print head, for example, to be printed on the surface (101a) of the substrate (101). In certain other examples, the one or more inorganic phosphor dopants (100) have a sufficiently narrow size distribution. For example, in certain other examples, the one or more inorganic phosphor dopants (100) have a diameter of about 0.01 to 0.5 μm, about 0.05 to 0.45 μm, about 0.10 to 0.3 μm, about 0.2 to 0.5 μm, about 0.4 to 0.5 μm, about 0.01 to 0.2 μm, about 0.2 to 0.3 μm, or about 0.35 to 0.45 μm. In some examples, the diameter of the one or more inorganic phosphor dopants (100) is 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, m, 0.24μm, 0.25μm, 0.26μm, 0.27μm, 0.28μm, 0.29μm, 0.30μm, 0.31μm, 0.32μm, 0.33μm, 0.34μm, 0.35μm, 0.36μm, 0. 37μm, 0.38μm, 0.39μm, 0.40μm, 0.41μm, 0.42μm, 0.43μm, 0.44μm, 0.45μm, 0.46μm, 0.47μm, 0.48μm, 0.49μm and 0.50μm. The size of the inorganic phosphor dopant (100) can be measured using, for example, 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”).

[0100] In certain examples of the above methods, the one or more inorganic phosphor dopants (100) are capable of emitting photons (105) having a wavelength of light of about 200nm to 280nm, 200nm to 270nm, about 200nm to 250nm, about 225nm to 250nm, about 200nm to 225nm, about 200nm to 275nm, or about 225nm to 275nm when exposed to a UV light source (104).

[0101] In certain examples of the above method, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 to 75 weight % to obtain the correct optical density according to the application of the UV curable ink composition (113). In certain other examples, including but not limited to the UV curable ink composition (113) is formulated as a graphic inkjet ink composition, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 to 50 weight %, about 1 to 25 weight %, about 1 to 15 weight %, about 1 to 10 weight %, about 1 to 5 weight %, about 1 to 3 weight % or about 1 to 2 weight %. In certain other examples, including but not limited to the UV curable ink composition (113) is formulated as a non-graphic ink composition, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 50 to 75 weight %, about 55 to 70 weight % or about 60 to 65 weight %. In some examples, the one or more inorganic phosphor dopants (100) are present in the UV curable ink composition (113) at about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% and 75 wt%.

[0102] For example, in S. Magdassi, Chemistry of Inkjet Inks; Chapter 10: Raw MSome suitable photoinitiators are described in industrial inkjet printing materials (114) and W. Zapka, Handbook of Industrial Inkjet Printing: A Full System Approach, Section 4.2 Photoinitiators. In certain examples of the above method, the 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, monoacylphosphine oxide (Lucerin TPO), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), azobisisobutyronitrile (AIBN), benzyl dimethyl ketal (BDK, Irgacure 651), 2-hydroxy-methyl-1-phenylpropane (Darocure 1173), hydroxycyclohexyl phenyl ketone (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, Esacure KIP150, monoacylphosphine oxide (MAPO) and bisacylphosphine oxide photoinitiator (BAPO).

[0103] In certain examples, the one or more photoinitiators (114) are preferably present in the UV curable ink composition (113) at about 0.1 to 15 weight percent in order to generate sufficient unpaired electrons or free radicals to facilitate polymerization of the monomer (115). When a mixture of photoinitiators (114) is used, the mixture can contain any suitable ratio of photoinitiators (114).

[0104] In some examples of the above method, the one or more monomers (115) are each independently an acrylate monomer. In some examples of the above method, the one or more monomers (115) are each independently 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), 1,3-butanediol diacrylate, di(trimethylolpropane) tetraacrylate, hexanediol diacrylate, ethoxy(3) cyclohexanol and / or dimethanol diacrylate. Such acrylate monomers (115) can be used as a binder (112) to improve one or more properties of the UV curable ink composition (113), such as pigment dispersion, adhesion, chemical resistance, mechanical resistance, UV resistance, etc. For example, in certain instances of the above method where little or no odor is desired, suitable acrylate monomers (115) may 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 cyclotrimethylolpropane formal acrylate (12 mPas at 25°C).

[0105] In certain examples of the above methods where moderate to high flexibility is desired (e.g., to apply a printed film on a contoured surface and resist cracking), suitable acrylate monomers (115) may 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) (higher degrees of ethoxylation up to 15 (EO); more flexible, less odor).

[0106] In certain other examples of the above methods where moderate hardness is desired (eg, to resist abrasion, scratching, and marring), suitable acrylate monomers (115) may include tricyclodecane dimethanol diacrylate (120 mPas at 25°C).

[0107] In certain other examples of the above methods where moderate toughness is required (e.g., to resist breakage due to impact), suitable acrylate monomers (115) may include isobornyl acrylate (10 mPas at 25°C) (very tough), isohexyl acrylate (6 mPas at 25°C) (high impact strength), 2-phenoxyethyl acrylate (2-PEA) (10 mPas at 25°C), dioxanediol 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).

[0108] In certain other examples of the above methods where good adhesion is desired (e.g., to resist removal from various substrates), suitable acrylate monomers (115) may include diethylene glycol butyl ether acrylate (5 mPas at 25° C.), 2(2-ethoxyethoxy)ethyl acrylate (5 mPas at 25° C.), tetrahydrofuranyl acrylate (5 mPas at 25° C.), isobornyl acrylate (10 mPas at 25° C.), cyclotrimethylolpropane methyl ester (115), ... aldehyde 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) (high versatility), dioxanediol diacrylate (25°C, 250 mPas) and / or propoxylated (2) neopentyl glycol diacrylate (18 mPas at 25°C).

[0109] In certain other examples of the above methods where good wetting is desired (e.g., to form 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 wetting) and / or propoxylated (3) trimethylolpropane triacrylate (100 mPas at 25°C).

[0110] In certain other examples of the above methods, the acrylate monomer (115) can be selected to impart sufficiently low viscosity (e.g., to enable jetting from a piezoelectric printhead, e.g., 6 cP to 25 cP at 25-60°C, depending on printhead manufacturer specifications) and / or chemical resistance (e.g., to withstand degradation due to exposure to any number of commercially available surface cleaners and disinfectants that might be used, for example, by airline operators).

[0111] It will be apparent to one of ordinary skill in the art based on this disclosure that the functionality of the acrylate will have an effect on various ink properties of the UV curable ink composition (113). For example, as described in W. Zapka, Handbook of Industrial Inkjet Printing: A Full System Approach, the effects on ink viscosity, reactivity, hardness, solvent resistance, and brittleness each increase as the acrylate functionality increases from monofunctionality to pentafunctionality. The effect on the flexibility of the UV curable ink composition (113) decreases as the acrylate functionality increases from monofunctionality to pentafunctionality, and the effect on the shrinkage of the UV curable ink composition (113) is lowest at monoacrylate functionality, highest at triacrylate functionality, and intermediate at pentaacrylate functionality.

[0112] In some examples of the above method, the method further comprises contacting one or more additives with the one or more inorganic phosphor dopants (100) and the one or more photoinitiators (114) and the one or more monomers (115). In some examples, the one or more additives are used to reduce surface tension and / or improve substrate wetting. By reducing surface tension, properties such as droplet formation and substrate wetting can be improved. In some examples of the above UV curable ink composition (113), the one or more additives are selected from the group consisting of alkoxylated, silicone, silicone-acrylated surfactants and fluorocarbons.

[0113] In some examples of the above method, the UV curable ink composition (113) has a viscosity of about 5 mPa-s to about 35 mPa-s. In some examples of the above method, the UV 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.

[0114] In certain examples of the above method, the one or more inorganic phosphor dopants (100) are each independently selected from the group consisting of metal oxides (106) and metal fluorides (108) containing rare earth ions (107), wherein the rare earth ions are selected from the group consisting of Pr 3+ 、Ce 3+ 、Eu3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof. In certain embodiments of the above method, the rare earth ion (107) is Pr +3 In some examples of the above method, the metal oxides (106) are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates or combinations thereof. In some examples, the silicate is selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates and orthosilicates. Non-limiting examples of silicates include Sr 2 MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl 2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10 SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi2 O 2 N 2 , where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 ) 2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O 12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca 2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 In some embodiments of the one or more inorganic phosphor dopants (100), the metal oxide (106) is doped with Pr 3+ Ca 2 Al 2 SiO 7 .

[0115] In certain examples of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from Cs 2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4Such metal fluoride (108) hosts are generally characterized by having large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful in inorganic phosphors. In certain examples, the one or more inorganic phosphor dopants (100) are doped with Pr 3+ Cs 2 NeA 6 (Cs 2 NeA 6 :Pr 3+ ). In the example, Pr 3+ Substitute Cs in an amount of about 0.3% to about 10% 2 NeA 6 In other examples, Pr 3+ Substituting Cs in an amount of about 1% to 5%, 1.5% to 4.5%, 2.5% to 5%, 2% to 7%, 3% to 8%, or 4% to 9%. 2 NeA 6 Yttrium ion sites in .

[0116] In certain examples, the one or more prepared inorganic phosphor dopants (100) are contacted with one or more photoinitiators (114) and one or more monomers (115). In certain examples of the above method, the one or more inorganic phosphor dopants (100) are in powder form and are combined with the photoinitiator (114) and the monomer (115). In certain examples where other functional ingredients such as pigments for color are included in the UV curable ink composition (113), the one or more inorganic phosphor dopants (100) can be mixed with the other functional ingredients before, at the same time, or after being combined with the photoinitiator (114) and the monomer (115).

[0117] In certain examples, one or more additives are further incorporated into or otherwise combined with the inorganic phosphor dopant (100), photoinitiator (114), and monomer (115), the incorporated additives being used to improve one or more properties of the UV curable ink composition (113), such as shelf life, fluidity, and / or adhesion. For example, the surface tension in the print head selected for the process of printing and / or coating the surface (101a) must be carefully controlled because it may affect the wettability and surface tension of the ink when droplets are formed during printing. In certain examples, surfactants help control the surface tension and can be used at about 0.1 to 2 weight percent. The one or more inorganic phosphor dopants (100), photoinitiator (114), monomer (115), and any optional functional ingredients and / or additives are then mixed to form the UV curable ink composition (113).

[0118] IV. Methods of coating surfaces

[0119] In certain examples, the subject matter described herein relates to coating a surface (101a) with one or more ink compositions (110) and / or UV curable ink compositions (113). It will be apparent to one of ordinary skill in the art based on this disclosure that such ink compositions (110) and / or UV curable ink compositions (113) can be used in a wide variety of applications for such disinfecting properties and improved light stability. It will also be apparent to one of ordinary skill in the art based on this disclosure that the ink compositions (110) and / or UV curable ink compositions (113) can be used to coat a surface (101a) via a variety of application methods depending on industrial and / or manufacturing needs. In certain examples, the ink compositions (110) and / or UV curable ink compositions (113) can be adjusted to be applied via any number of coating techniques, such as dipping, spraying / atomizing, roller coating, or brushing. Those of ordinary skill in the art will appreciate that since the inorganic phosphor dopant (100) will be present in a relatively small amount compared to the colorant loading of the colored coating, the formulation may be modified and / or rebalanced to support application in order to produce a stable liquid compatible with an application tool (e.g., a paint spray gun, an inkjet print head, etc.) and then applied via any one or more of such application tools. For example, Table 1 provides an overview of exemplary application methods, associated coverage, how such coating is performed, and identification of types of substrate (101) materials and / or components that may be coated by the associated methods.

[0120] Table 1

[0121]

[0122] V. Methods for Disinfecting Surfaces

[0123] In certain examples, the subject matter described herein relates to a method for disinfecting a surface (101a), wherein the surface (101a) is coated with an ink composition (110) comprising one or more inorganic phosphor dopants (100), a solvent (111), and a binder (112), the method comprising exposing the surface (101a) coated with the ink composition (110) to a UV light source (104) in step 350 to charge the one or more inorganic phosphor dopants (100) in the ink composition (110), wherein in step 355, the exposure causes 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, and the photons (105) irradiate the surface (101a), thereby disinfecting the surface (101a), such as Figure 3After the ink composition (110) is dried and / or cured, the surface (101a) of the substrate (101) is coated with the inorganic phosphor dopant (100), any functional components (eg, pigments for color), and a binder (112).

[0124] In other examples, the subject matter described herein relates to a method for disinfecting a surface (101a), wherein the surface (101a) is coated with a UV-curable ink composition (113), wherein the UV-curable ink composition comprises: one or more inorganic phosphor dopants (100); one or more photoinitiators (114); and one or more monomers (115), the method comprising: in step 350, exposing the surface (101a) coated with the UV-curable ink composition (113) to a UV light source (104), wherein, in step 355, the exposure causes the one or more inorganic phosphor dopants (100) in the UV-curable ink composition (113) to emit photons (105) having a wavelength of light in the UV-C range, and the photons (105) irradiate the surface (101a), thereby disinfecting the surface (101a), such as Figure 3 After the UV curable ink composition (113) is cured, the surface (101a) of the substrate (101) is coated with the inorganic phosphor dopant (100), any functional components (eg, pigments for color), and polymers.

[0125] When a phosphor is exposed to radiation, orbital electrons in its molecules are excited to a higher energy level; when they return to their previous energy level, they emit energy as light of a specific color. In fact, the scintillation process in inorganic materials is due to the electronic band structure present in the crystal. Incoming particles can excite electrons from the valence band to the conduction band or 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 electronic energy levels in the forbidden band. Excitons are loosely bound electron-hole pairs that diffuse through the crystal lattice until they are captured as a whole by an impurity center. The latter then quickly de-excite by emitting scintillation light, i.e., photons (105). The wavelength of the emission depends on the atom itself and the surrounding crystal structure.

[0126] In some examples, the UV light source (104) used to excite (i.e., charge) the orbital electrons of the inorganic phosphor dopant (100) has a wavelength of about 160 nm to 320 nm. In other examples, the UV light source (104) has a wavelength of about 160 nm to 260 nm, about 160 nm to 200 nm, about 180 nm to 240 nm, about 200 nm to 250 nm, about 210 nm to 250 nm, about 225 nm to 260 nm, about 230 nm to 250 nm, or about 190 nm to 260 nm. In some other examples, the UV light source (104) has a wavelength of about 222 nm, 254 nm, or 275 nm.

[0127] Non-limiting examples of UV light sources (104) include, for example, black lights, short-wave UV lamps, incandescent lamps, gas discharge lamps, UV LEDs, deuterium lamps, pulsed xenon lamps, and UV lasers. In an example, the UV light source (104) is a pulsed xenon UV device, which can be in the form of a handheld wand. The UV light emitted from the pulsed xenon device enables effective charging of the inorganic phosphor dopant (100) in the ink composition (110) and / or the UV curable ink composition (113), and can sterilize the coated surface (101a) by hovering the xenon UV wand about 1 to 5 inches above the surface (101a). In another example, the UV light source (104) is a deuterium lamp, which has a light range of about 185nm to about 400nm.

[0128] In addition to the UV light source (104), other excitation energy sources may also be used in the methods described herein. Personal protective equipment (PPE) may be required to operate such energy sources.

[0129] In some examples, the emitted radiant energy used for disinfection may not have color (i.e., UV light). In certain examples of the above methods, the inorganic phosphor dopant (100) in the ink composition (110) and / or the UV curable ink composition (113) emits photons (105) having a light wavelength of about 200 nm to 280 nm. In other examples, the inorganic phosphor dopant (100) in the ink composition (110) and / or the UV curable ink composition (113) emits photons (105) having a light wavelength of about 200 nm to 270 nm, about 200 nm to 250 nm, about 225 nm to 250 nm, about 200 nm to 225 nm, about 200 nm to 275 nm, or about 225 nm to 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 example, the inorganic phosphor dopant (100) emits UV-C light having a wavelength of about 200 to 280 nm.

[0130] In some instances, the inorganic phosphor dopant (100) is a metal oxide (106) or metal fluoride (108) containing a rare earth ion (107) or a transition metal ion. In some instances, the rare earth ion (107) or the transition metal ion is referred to as an "activator ion". As used herein, an "activator ion" is an ion added to a crystal structure as a dopant. The activator ion is surrounded by the host crystal ion and forms a luminescent center where the excitation-emission process of the phosphor occurs. The wavelength emitted by the activator ion is affected by the ion itself, its electronic configuration, and its surrounding crystal structure.

[0131] Although the activator ions have intrinsic properties that contribute to the optical properties of the phosphor, the electronic energy levels of the activator ions in the crystal are different from those of the free ions. Depending on the properties of the host crystal, the separation of the energy levels can cause light emission from UV across visible wavelengths. The local geometric structure around the activator ions affects the spectral behavior of the activator ions, especially lanthanide ions, incorporated into the host matrix. Certain effects in the lattice, such as ligand field splitting and mass center shift, may affect the energy gap between the f and d orbitals of the activator ions, thereby affecting the luminescent properties of this material (Lin, YC et al., Top Curr Chem (Z) 374, 21 (2016)).

[0132] In some examples, the one or more inorganic phosphor dopants (100) are metal oxides (106) containing rare earth ions (107). In some examples, the rare earth ions (107) are lanthanide ions. In some examples, the rare earth ions (107) are selected from Tm 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+ He Lu 3+ In some examples, the one or more inorganic phosphor dopants (100) are metal oxides (106) containing rare earth ions (107), wherein the rare earth ions are 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 certain embodiments, the rare earth ion (107) is Pr 3+ .

[0133] Pr 3+ The UV-C emission of the activated UV-C phosphor consists of a broad, parity-allowed Pr 3+ 4f 1 5d 1 →4f 2 In order to ensure that Pr 3+ 4f 1 5d 1 →4f 2 Transition requires two general conditions: less than about 3000cm -1 The small Stokes shift of (0.37 eV) and the first (lowest energy) Pr 3+ 4f 2 →4f 1 5d 1 The appropriate energy position for the excitation transition is related to the composition and crystal structure of the host lattice. Under these conditions, Pr 3+ 4f 1 5d 1 Energy level to lower 4f 2 ( 3 P J , 1 I 6 , 1 D 2 ) levels is minimized; otherwise, 4f 1 5d 1 Energy levels and lower 4f 2 Energy level jumps, resulting in sharp lines of visible and infrared emission 4f 2 →4f 2 Inter-configuration emission transmission will dominate (Wang, X. et al., Nat Commun 11, 2040 (2020)).

[0134] In certain examples of the 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. Such metal oxides (106) are ceramic materials and therefore exhibit several advantages, including chemical, thermal and photochemical stability. In certain examples, the silicate is selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates and orthosilicates. Non-limiting examples of silicates include Sr. 2MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl 2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10 SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi 2 O 2 N 2 , where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 ) 2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca 2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 .

[0135] In some examples of the one or more inorganic phosphor dopants (100), the metal oxide (106) is doped with Pr 3+ Ca 2 Al 2 SiO 7 (Ca 2 Al 2 SiO 7 :Pr 3+ ). Ca 2 Al 2 SiO 7 is characterized by a pyroxene structure in which Ca 2+ The ions are sandwiched between the AlO 4 and SiO 4 between tetrahedral layers and are eight-coordinated. Each Ca 2+ Ions and AlO 4 Layer and SiO 4 The four nearest neighbors of the two layers O 2- The ligands are ionically bonded, so the four Ca 2+ The complexes are structurally identical. 2 Al 2 SiO 7 :Pr 3+ In the trivalent Pr 3+ ion Replace smaller divalent Ca 2+ ion Therefore, the doped Pr 3+ The ion is eight-coordinated. This highly coordinated, small, and charge-unbalanced cationic site can be used for Pr 3+ The ions generate a suitably strong crystal field through which a small Stokes shift and thus efficient Pr for UV-C emission can occur. 3+ 4f 1 5d 1 →4f 2 Again, without wishing to be bound by theory, it is expected that cation size mismatch and charge imbalance will occur in the Pr 3+ More efficient energy traps (such as oxygen vacancies) are created around the ions, which helps to produce efficient persistent phosphors (Wang, X et al., Nat Commun 11, 2040 (2020)).

[0136] In certain examples of the one or more inorganic phosphor dopants (100), the metal fluoride (108) (host lattice) is selected from Cs 2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4 Such metal fluoride (108) hosts are generally characterized by having large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful in inorganic phosphors. In certain examples, the one or more inorganic phosphor dopants (100) are doped with Pr 3+ Cs 2 NeA 6 (Cs 2 NeA 6 :Pr 3+ ). In the example, Pr 3+ Substitute Cs in an amount of about 0.3% to about 10% 2 NeA 6 In other examples, Pr 3+ Substituting Cs in an amount of about 1% to 5%, 1.5% to 4.5%, 2.5% to 5%, 2% to 7%, 3% to 8%, or 4% to 9%. 2 NeA 6 Yttrium ion sites in .

[0137] The ink composition (110) and / or UV curable ink composition (113) described herein can be applied to nearly any surface (101a) for surface disinfection. In fact, as described herein, the ink composition (110) and / or UV curable ink composition (113) has disinfecting properties when exposed to a UV light source (104). In certain examples, the coated surface (101a) is located in an airplane, hospital, gym, school, or other area where there is a significant risk of contaminant transfer.

[0138] In certain instances of the above method, the coated surface (101a) is the interior of an aircraft. In certain other instances of the above method, the coated surface (101a) is located in a hospital, a gymnasium, or a school. In another instance of the above method, the surface (101a) is located where there is a significant risk of contaminant transfer.

[0139] In an example of the above method for disinfecting a surface (101a), the surface (101a) is exposed to a UV light source (104) for a time sufficient to charge the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the UV curable ink composition (113). In certain examples, the time sufficient to charge the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or UV curable ink composition (113) is 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 the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or UV curable ink composition (113) will vary depending on the wavelength of the UV light and the one or more inorganic phosphor dopants (100) themselves.

[0140] In an example of the above method for disinfecting a surface (101a), the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or UV 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 the one or more inorganic phosphor dopants (100) emit photons (105) can be adjusted, for example, by modifying the length of time used to charge the one or more inorganic phosphor dopants (100). The duration of emission can also be adjusted depending on the desired application. For example, if the surface (101a) being disinfected is located in an airplane, a suitable maximum emission time is about 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes so that the disinfection process can be performed between flights. In certain other instances, longer emission times may be associated with higher levels of disinfection. For example, if the surface (101a) being disinfected is located in a hospital or medical facility, the emission time may be about 30 minutes to 60 minutes, as higher levels of disinfection may be required in this type of facility.

[0141] One or more dopant ions can be used to tune the emission to longer or shorter wavelengths, as well as to vary the emission intensity. For example, SrAl 2 O 4 Can be doped with Eu 2+ , a phosphor emitting at 520 nm is obtained. However, SrAl 2 O 4 You can also use Eu 2+ and Dy 3+ Co-doping can significantly enhance the sustained luminescence intensity. 2 O 4 :Eu 2+ ,Dy 3+ The afterglow lasts for hours, which is the result of the gradual thermally assisted release of trapped charges in the phosphor. This long afterglow contrasts with the duration of only a few minutes of the variant without the co-dopant (Xingdong, L. et al., J. Wuhan Univ. Technol.-Mat. Sci. Edit. 23, 652–657 (2008)). In addition, the material can be stabilized with an inorganic phosphor dopant (100) having an energy well that can be filled during excitation. The energy well can be adjusted by adjusting the desired penetration depth of the UV energy to adjust the decay time required to clean the surface (101a) over time.

[0142] When light emitted by the inorganic phosphor dopant (100) in the ink composition (110) and / or UV curable ink composition (113) material leaves the surface (101a), it isotropically irradiates the surface (101a), thereby sterilizing the surface (101a). Isotropic irradiation means that the radiation from the point source radiates uniformly in all directions with the same intensity regardless of the direction of measurement. The light emitted by the one or more inorganic phosphor dopants (100) is short wavelength ultraviolet (ultraviolet C or UV-C) light having a wavelength of 200 nm to 280 nm or 225 nm to 250 nm, which is known to be sterilizing.

[0143] In certain embodiments of the method for disinfecting a surface (101a), the UV light source (104) has a wavelength of about 160 to 260 nm; the one or more inorganic phosphor dopants (100) are Pr 3+ silicate; and the inorganic phosphor dopant (100) emits photons (105) having a light wavelength of about 265 nm.

[0144] VI. Method for Improving Color Stability of Synthetic Polymers

[0145] See also Figure 4 In certain examples, the subject matter described herein relates to a method for improving the color stability of a synthetic polymer (121) comprising a surface (101a), wherein the surface (101a) is coated with an ink composition (110), wherein the ink composition (110) comprises: one or more inorganic phosphor dopants (100), a solvent (111) and a binder (112), wherein the method includes exposing the surface (101a) of the synthetic polymer (121) coated with the ink composition (110) to UV light in step 450 to charge the one or more inorganic phosphor dopants, wherein in step 455, the one or more inorganic phosphor dopants (100) in the ink composition (110) absorb the UV light and then cause the one or more inorganic phosphor dopants (100) to emit the UV light as down-converted visible light (116), thereby producing a brighter appearance for the synthetic polymer (121), such as Figure 4 shown.

[0146] See also Figure 4In certain other examples, the subject matter described herein relates to a method for improving the color stability of a synthetic polymer (121) comprising a surface (101a), wherein the surface (101a) is coated with a UV curable ink composition (113), wherein the UV curable ink composition (113) includes: one or more inorganic phosphor dopants (100), one or more photoinitiators (114) and one or more monomers (115), wherein the method includes exposing the surface (101a) of the synthetic polymer (121) coated with the UV curable ink composition (113) to UV light in step 450 to charge the one or more inorganic phosphor dopants, wherein in step 455, the one or more inorganic phosphor dopants (100) in the UV curable ink composition (113) absorb the UV light and then cause the one or more inorganic phosphor dopants (100) to emit the UV light as down-converted visible light (116), thereby producing a brighter appearance for the synthetic polymer (121), such as Figure 4 shown.

[0147] When a phosphor is exposed to radiation, the orbiting electrons in its atoms are excited to a higher energy level; when they return to their previous energy level, they emit energy as light of a specific color. In fact, the scintillation process in inorganic materials is due to the electronic band structure present in the crystal. Incoming particles can excite electrons from the valence band to the conduction band or 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 electronic energy levels in the forbidden band. Excitons are loosely bound electron-hole pairs that diffuse through the crystal lattice until they are captured as a whole by an impurity center. The latter then quickly de-excite by emitting scintillation light, i.e., photons (105). The wavelength of the emission depends on the atoms themselves and the surrounding crystal structure.

[0148] As described herein, the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or UV curable ink composition (113) absorb UV light and emit the UV light as down-converted visible light (116). In certain examples, the UV light used to excite (charge) orbital electrons of the one or more inorganic phosphor dopants (100) has a wavelength of about 160 nm to 380 nm. In other examples, the UV light has a wavelength of about 160 nm to 320 nm, about 160 nm to 260 nm, about 160 nm to 200 nm, about 180 nm to 240 nm, about 200 nm to 250 nm, about 250 nm to 380 nm, about 210 nm to 250 nm, about 225 nm to 260 nm, about 230 nm to 250 nm, or about 190 nm to 260 nm. In certain other instances, the UV light has a wavelength of approximately 222 nm, 254 nm, or 275 nm.

[0149] Non-limiting examples of UV light sources (104) for providing UV light in the above method include, for example, black lights, short-wave UV lamps, incandescent lamps, gas discharge lamps, UV LEDs, deuterium lamps, pulsed xenon lamps, and UV lasers. For example, the UV light source (104) can be a pulsed xenon UV 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), wherein the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the UV curable ink composition (113) absorb UV light. In another example, the UV light source (104) for providing UV light is a deuterium lamp having a light range of about 185 nm to about 400 nm.

[0150] In addition to the UV light source (104), other excitation energy sources may also be used in the methods described herein. Personal protective equipment (PPE) may be required to operate such energy sources.

[0151] In certain examples of the above-described method for improving the color stability of a synthetic polymer (121), the absorption of UV light by the one or more inorganic phosphor dopants (100) reduces photo-oxidation of the synthetic polymer (121). As used herein, reducing photo-oxidation of the synthetic polymer (121) refers to a reduction in discoloration and / or embrittlement of the synthetic polymer (121) when exposed to UV light, because the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) absorb most of the UV light instead of the synthetic polymer (121) itself. Given the different behaviors of UV absorption in the synthetic polymer (121), the specific reduction of photo-oxidation is material-dependent. The one or more inorganic phosphor dopants (100) generally exhibit very strong absorption. Thus, incorporation of the one or more inorganic phosphor dopants (100) into the ink composition (110) and / or the UV curable ink composition (113) on the surface (101a) of the synthetic polymer (121) can reduce photo-oxidation 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%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 80%, 81%, 82%, 83%, 85%, 86%, 88%, 80%, 81%, 83%, 85%, 86%, 88%, 82%, 83%, 85%, 88%, 8 %, 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%. For example, infrared spectroscopy can be used to detect the photo-oxidation of materials. In particular, the peroxy species and carbonyl groups formed by photo-oxidation generally contain different absorption bands.

[0152] In certain examples of the method for improving the color stability of a synthetic polymer (121), the visible light (116) emitted by the one or more inorganic phosphor dopants (100) creates a brighter appearance for the synthetic polymer (121). An observer observing the synthetic polymer perceives the brighter appearance (121). In fact, "brightness" as used herein is a property of visual perception that a source appears to be radiated or reflected light. Brightness is a perception caused by the brightness of a visual object. In certain examples, the one or more inorganic phosphor dopants (100) can emit blue visible light (116) with a wavelength of 450nm to 495nm. The blue visible light (116) emitted from the ink composition (110) and / or the UV curable ink composition (113) containing the 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 emission, where certain dopants in a broadly emitting material have the effect of making the entire material appear visually brighter.

[0153] In certain examples of the method for improving the color stability of a synthetic polymer (121), the light emitted by the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the UV curable ink composition (113) is down-converted visible light (116). In certain examples of the above method, the one or more inorganic phosphor dopants (100) emit visible light (116) having a wavelength of about 200 to 700 nm. In other examples, the one or more inorganic phosphor dopants (100) emit visible light (116) having a wavelength of about 400nm to 495nm, about 620nm to 700nm, about 590nm to 620nm, about 570nm to 590nm, about 495nm to 570nm, about 390nm to 450nm, about 380nm to 600nm, about 350nm to 460nm, about 600nm to 700nm, about 450nm to 600nm, about 200nm to 280nm, about 450nm to 495nm, about 380nm to 450nm, about 200nm to 270nm, about 200nm to 250nm, about 225nm to 250nm, about 200nm to 225nm, about 200nm to 275nm, or about 225nm to 275nm. A specific wavelength or wavelength range may be selected based on the desired color of the emitted light. For example, if the inorganic phosphor dopant (100) is desired to emit blue light, a phosphor is selected that emits visible light (116) having a wavelength of about 400nm to 495nm. In certain other instances, if the inorganic phosphor dopant (100) is desired to emit green light, a phosphor is selected that emits visible light (116) having a wavelength of about 495nm to 570nm. In other instances, if the inorganic phosphor dopant (100) is desired to emit violet light, a phosphor is selected that emits visible light (116) having a wavelength of about 380nm to 450nm. In certain other instances, if the inorganic phosphor dopant (100) is desired to emit yellow light, a phosphor is selected that emits visible light (116) having a wavelength of about 570nm to 590nm. In another example, if the inorganic phosphor dopant (100) is desired to emit orange light, a phosphor emitting visible light (116) having a wavelength of about 590 nm to 620 nm is selected. In addition, in other examples, if the inorganic phosphor dopant (100) is desired to emit red light, a phosphor emitting visible light (116) having a wavelength of about 620 nm to 700 nm is selected.

[0154] In certain examples of the method for improving the color stability of a synthetic polymer (121), the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises two or more inorganic phosphor dopants (100), wherein the down-converted visible light (116) emitted by the two or more inorganic phosphor dopants (100) is combined to produce white light or off-white light. In certain examples of the method for improving the color stability of a synthetic polymer (121), the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises three or more inorganic phosphor dopants (100), wherein the down-converted visible light (116) emitted by the three or more inorganic phosphor dopants (100) is combined to produce white light or off-white light. For example, an inorganic phosphor dopant (100) emitting blue visible light (116) having a wavelength of about 450 nm to 495 nm can be inserted into an ink composition (110) and / or a UV curable ink composition (113) that coats the surface (101a) of a synthetic polymer (121) with a second inorganic phosphor dopant (100) emitting yellow visible light (116) having a wavelength of about 570 nm to 590 nm. The combination of the blue and yellow visible light (116) emitted by the first and second inorganic phosphor dopants (100) will produce white or off-white emission (white visible light (116)). In a similar manner, a first inorganic phosphor dopant (100) emitting blue visible light (116) having a wavelength of about 450 nm to 495 nm can be inserted into an ink composition (110) and / or a UV curable ink composition (113) that coats a surface (101a) of a synthetic polymer (121) with a second inorganic phosphor dopant (100) emitting green visible light (116) having a wavelength of about 495 nm to 570 nm and a third inorganic phosphor dopant (100) emitting red visible light (116) having a wavelength of about 620 nm to 750 nm. The combination of blue, green and red visible light (116) emitted by the first, second and third inorganic phosphor dopant (100) will produce white or off-white emission (white visible light (116)).

[0155] In certain examples of the method for improving the color stability of a synthetic polymer (121), the synthetic polymer (121) having a surface (101a) is thermoplastic or thermosetting. In certain examples, the synthetic polymer (121) is selected from the group consisting of tetrafluoroethylene, polyvinyl fluoride, polyurethane, polyester, epoxy resin, phenolic resin, vinyl ester, polyamide, polyamide-imide, polyetherimide, polyvinyl chloride, polyetherketoneketone, polycarbonate, polyphenylsulfone, polymethyl methacrylate, polyacrylate and benzoxazine. In particular, fluorine is known to strongly resist photooxidation due to its high electronegativity and the need to accept electrons. Therefore, in certain examples, fluorinated synthetic polymers such as tetrafluoroethylene or polyvinyl fluoride can be used for the synthetic polymer (121) in the method described herein. In addition, thermosetting polymers are generally known to have a higher degree of crosslinking than other types of polymers, which makes them further resistant to photooxidation.

[0156] In certain examples of the method for improving the color stability of a synthetic polymer (121), the 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, "activator ions" are ions added to the crystal structure as dopants. Activator ions are surrounded by host crystal ions and form luminescent centers where the excitation-emission process of the phosphor occurs. The wavelength emitted by the activator ion depends on the ion itself, its electronic configuration, and the crystal structure around it. In certain examples, the rare earth ion (107) is a lanthanide ion. In certain examples, the rare earth ion (107) is selected from Tm 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+ He Lu 3+ In some examples, the one or more inorganic phosphor dopants (100) are metal oxides (106) or metal fluorides (108) containing rare earth ions (107), wherein the rare earth ions (107) are selected from the group consisting of Pr 3+ 、Ce 3+ 、Eu3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof. In certain examples, the one or more inorganic phosphor dopants (100) are metal oxides (106) containing rare earth ions (107). In an example, 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 specific color and wavelength. For example, it is expected that the dopant in Y 2 O 3 Eu 3+ The emission wavelength is about 611nm red-orange visible light (116), and it is expected that the doped InBO 3 Eu 3+ The emission wavelength is about 588nm yellow visible light (116). In another example, BaMg can be doped 2 Al 16 O 27 Eu 2+ , which is expected to emit blue visible light (116) having a wavelength of about 450 nm.

[0157] In certain embodiments of the method for improving the color stability of a synthetic polymer (121), the one or more inorganic phosphor dopants (100) are metal fluorides (108) selected from the group consisting of Cs 2 NeA 6 、NaCeF 4 ,NaYF 4 and NaGd 4 The metal fluoride (108) hosts are generally characterized by large band gaps, structural defects that may act as electron traps, and anion defects, which make them useful as inorganic phosphors.

[0158] In certain examples of the method for improving the color stability of a synthetic polymer (121), the 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 certain examples, the silicate is selected from the group consisting of pyroxene, cyclosilicates, silicate garnets, oxyorthosilicates and orthosilicates. Non-limiting examples of silicates include Sr, 2 MgSi 2 O 7 , Ca 2 Al 2 SiO 7 、SrAl2 O 4 MgSiO 3 、SrSiO 3 、CdSiO 3 , Ba 2 SiO 4 、BaMg 2 Si 2 O 7 , Ca 2 MgSi 2 O 7 , Sr 0.5 Ca 1.5 MgSi 2 O 7 、(Ca,Sr) 2 MgSi 2 O 7 , Sr 3 MgSi 2 O 8 , Sr 2 MgSi 2 O 7 , Ca 0.5 Sr 1.5 Al 2 SiO 7 , Sr 3 Al 10 SiO 20 and Y 2 SiO 5 Non-limiting examples of borates include YBO 3 and CaAl 2 B 2 O 7 Non-limiting examples of oxynitrides include MSi 2 O 2 N 2 , where M = Ba, Sr or Ca. Non-limiting examples of phosphates include YPO 4 and Zn 3 (PO 4 ) 2 Non-limiting examples of oxides include CaO, SrO, BaO, Y 3 Ga 5 O 12 、NaGdGeO 4 、Cd 3 Al 2 Ge 3 O 12 、CaTiO 3 , Ca 0.8 Zn 0.2 TiO 3 and Ca2 Zn 4 Ti 15 O 36 Non-limiting examples of oxysulfides include Y 2 O 2 S, Gd 2 O 2 S and Sr 5 Al 2 O 7 S. Non-limiting examples of aluminates include MgAl 2 O 4 , CaAl 2 O 4 、SrAl 2 O 4 and Sr 4 Al 14 O 25 .

[0159] In certain examples, the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises two different inorganic phosphor dopants (100), wherein each inorganic phosphor dopant (100) is a metal oxide (106) or a metal fluoride (108) containing a rare earth ion (107), and the combined emission of the two inorganic phosphor dopants (100) produces white or off-white visible light (116). In certain examples, the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises two different inorganic phosphor dopants (100), wherein 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 UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) may include a Y-ray diffraction pattern that emits blue visible light (116) having a wavelength of about 400 nm. 2 SiO 5 : Ce(III) first inorganic phosphor dopant (100) and InBO (116) emitting yellow visible light with a wavelength of about 588 nm 3 The combined visible light (116) will together produce white or off-white visible light (116).

[0160] In some examples, the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises three different inorganic phosphor dopants (100), wherein each inorganic phosphor dopant (100) is a metal oxide (106) or a metal fluoride (108) containing a rare earth ion (107), and the combined emission of the three inorganic phosphor dopants (100) produces white or off-white visible light (116). For example, in some examples, the ink composition (110) and / or the UV curable ink composition (113) coating the surface (101a) of the synthetic polymer (121) comprises BaMgO2 that emits blue visible light (116) having a wavelength of about 450 nm. 2 Al 16 O 27 : Eu(II) first inorganic phosphor dopant (100), Y emitting green visible light (116) with a wavelength of about 545 nm 2 SiO 5 :Tb(III) second inorganic phosphor dopant (100) and Y emitting red visible light (116) with a wavelength of about 611 nm 2 O 3 The combined visible light (116) will together produce white or off-white visible light (116).

[0161] In certain examples of the method for improving the color stability of a synthetic polymer composition, the surface (101a) of the synthetic polymer (121) is located in the interior of an aircraft. In certain other examples, the surface (101a) of the synthetic polymer (121) is a substrate (101) or surface (101a) located in a hospital or other medical institution, a school, a gym, or a car.

[0162] In certain examples of the method for improving the color stability of a synthetic polymer composition, the surface (101a) is exposed to UV light for a time sufficient to charge the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the UV curable ink composition (113). In certain examples, the time sufficient to charge the one or more inorganic phosphor dopants (100) in the ink composition (110) and / or the UV 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.

[0163] The one or more inorganic phosphor dopants (100) absorb UV light and emit the UV light as down-converted visible light (116) for a period of time typically on the order of nanoseconds. In addition, in examples, the phosphor absorbs energy and does not release the light immediately. Instead, in examples, the energy is dissipated to the lowest excited state in picoseconds before emission. In certain examples, by applying continuous irradiation, for example, the one or more inorganic phosphor dopants (100) continuously absorb UV light and emit the UV light as down-converted visible light (116).

[0164] In certain other examples, persistent phosphors may be applied in the above methods to improve the color stability of the synthetic polymer (121). Persistent phosphors differ from ordinary conversion phosphors in that they exhibit light emission that lasts from seconds to hours after excitation ceases. The reason for this delayed emission is their ability to store energy in the material, possibly at defects other than the luminescent "activator" ions. These defects are called wells because charge carriers originating from the luminescent ions are locally trapped at the defects. When sufficient energy is provided to the trapped charge, it will be released. After recombination at the luminescent ion, it will produce a delayed emission commonly known as afterglow. The time span of the afterglow can be adjusted because it depends on the so-called depth of the well, which is usually detected by thermoluminescence. For example, it is generally understood that shallow wells are easy to empty, while deep wells are difficult to empty at room temperature; a portion of the trapped electrons remain stored there. If the well is too deep, the trapped electrons cannot escape, preventing a continuous afterglow. Thermoluminescence can be used to assess the well depth. In fact, the thermoluminescence glow curve represents the relationship between the intensity of the emitted light and the temperature; each glow peak is associated with a recombination center and is associated with a specific well. Glow curves can provide useful information for materials. For example, activation energy and escape frequency factor can be calculated from the glow curve. Many methods can be used to calculate well parameters based on the kinetic series of the glow peak, such as the initial rise method and variable heating rate. Based on the glow curve, the luminous efficiency of the material can be obtained.

[0165] The change of the structure-luminescence property of the material can be observed by the modification of its glow curve. For example, the reduction of the thermoluminescence intensity can sometimes be attributed to the inhibition of the well. In other examples, the luminous efficiency of the material can be increased after impurities (such as other ions) are added to the phosphor. The presence of such impurities can modify the well distribution and deepen the well sites caused by the modification of the energy gap in the phosphor. The thermoluminescence glow curve can be obtained using a thermoluminescence measuring instrument such as a FJ-427A TL meter.

[0166] In certain other instances, electronic transitions in phosphors may be characterized as "forbidden". Forbidden transitions are spectral lines associated with the absorption or emission of a photon (105) by a nucleus or atom that undergoes a transition that is not permitted by a particular selection rule, but that is permitted if the approximation associated with the rule is not performed. For example, under the usual approximation (e.g., the electric dipole approximation for interaction with light), the process cannot occur, but under a higher level of approximation (i.e., the magnetic dipole), the process is allowed but at a slower rate. An example of such a forbidden transition is observed in phosphorescent materials, which absorb light and form an excited state whose decay involves a spin flip, which is forbidden by the electric dipole transition. The result is a slow emission of light over minutes or hours. In practice, "forbidden" transitions occur at a much slower rate than "allowed" transitions. "Allowed" transitions are transitions that: obey the appropriate (1) spin and (2) Laporte (orbital) selection rules; exhibit a change in parity (symmetry) during the transition; emit a photon with an energy that matches the gap between the ground and excited states; and which exhibit a change in dipole moment. The allowed spin selection rules dictate that the spin orientation should not change (i.e., no spin reversal occurs during an electronic transition). According to the Laporte selection rules, transitions between similar atomic orbitals, such as ss, pp, dd, or ff transitions, are forbidden in a centrosymmetric environment. Even when a transition may be forbidden, it is often coupled to vibrational factors that reduce, for example, the molecular symmetry of the system and cause some previously forbidden transitions to be allowed due to the reduced symmetry. This generally results in weaker allowed transitions and in reduced transition rates. Typical emission lifetimes for materials that undergo forbidden transitions can be milliseconds or even seconds.

[0167] As described above, in certain examples, the one or more inorganic phosphor dopants (100) can be used to tune the emission to longer or shorter wavelengths and also produce white light.

[0168] In certain examples of the method for improving the color stability of a synthetic polymer (121), the synthetic polymer (121) is a thermoplastic material; the ink composition (110) and / or the UV curable ink composition (113) comprises two inorganic phosphor dopants (100), wherein the first inorganic phosphor dopant (100) is Y 2 SiO 5 : Ce(III), which emits blue visible light (116) with a wavelength of about 400 nm; the second inorganic phosphor dopant (100) is InBO 3: Eu(III) emitting yellow visible light (116) with a wavelength of about 588 nm. The phosphor in the ink composition (110) coated with the synthetic polymer (121) and / or the UV curable ink composition (113) is exposed to UV light using a xenon UV rod for about 10 minutes and then emits visible light (116), which is combined to produce white visible light (116).

[0169] Additionally, this disclosure includes examples of the following clauses:

[0170] Item 1. An ink composition comprising: one or more inorganic phosphor dopants; a solvent; and a binder.

[0171] Item 2. The ink composition of Item 1, wherein the one or more inorganic phosphor dopants have a diameter no greater than 0.5 μm.

[0172] Item 3. The ink composition of Item 1 or 2, wherein the one or more inorganic phosphor dopants are each independently selected from the group consisting of metal oxides and metal fluorides containing rare earth ions, wherein the rare earth ions are selected from Pr 3+ 、Ce 3+ 、Eu 3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof.

[0173] Item 4. The ink composition as described in Item 3, wherein the rare earth ion is Pr 3+ .

[0174] Item 5. The ink composition of Item 3 or 4, wherein the metal oxides are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates, or combinations thereof.

[0175] Item 6. An ink composition as described in any of Items 1 to 5, wherein the solvent is selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, butanol, acetone, tetrahydrofuran, dioxane, 2-pyrrolidone, N-methyl-2-pyrrolidone, dimethyl sulfoxide, ethylene glycol ether, propylene glycol ether, ester, cyclohexanone, isophorone and alkyl lactate.

[0176] Clause 7. The ink composition of 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.

[0177] Clause 8. The ink composition of any of Clauses 1-7, wherein the ink composition has a viscosity of about 2 mPa-s to about 30 mPa-s.

[0178] Clause 9. The ink composition of any one of Clauses 1-8, wherein the ink composition is formulated as an aerosol spray.

[0179] Item 10. A UV curable ink composition comprising: one or more inorganic phosphor dopants; one or more photoinitiators; and one or more monomers.

[0180] Item 11. The UV curable ink composition of Item 10, wherein the one or more inorganic phosphor dopants have a diameter no greater than 0.5 μm.

[0181] Item 12. The UV curable ink composition of Item 10 or 11, wherein the one or more inorganic phosphor dopants are each independently selected from the group consisting of metal oxides and metal fluorides containing rare earth ions, wherein the rare earth ions are selected from Pr 3+ 、Ce 3+ 、Eu 3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof.

[0182] Item 13. The UV curable ink composition according to Item 12, wherein the rare earth ion is Pr 3+ .

[0183] Item 14. The UV curable ink composition according to Item 12 or 13, wherein the metal oxides are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates, or combinations thereof.

[0184] Clause 15. A UV curable ink composition as described in any one of Clauses 10 to 14, wherein the 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), benzyl dimethyl ketal (BDK, Irgacure 651), 2-hydroxy-methyl-1-phenylpropane (Darocure 1173), hydroxycyclohexyl phenyl ketone (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, monoacylphosphine oxide (Lucerin TPO), Esacure KIP150, monoacylphosphine oxide (MAPO) and bisacylphosphine oxide photoinitiator (BAPO).

[0185] Clause 16. The UV curable ink composition of any one of Clauses 10-15, wherein the one or more monomers are each independently an acrylate monomer.

[0186] Item 17. The UV curable ink composition of any one of Items 10-16, further comprising one or more additives for reducing surface tension and / or improving substrate wetting.

[0187] Clause 18. The UV curable ink composition of any one of Clauses 10-17, wherein the UV curable ink composition has a viscosity of about 5 mPa-s to about 35 mPa-s.

[0188] Clause 19. The ink composition of any one of Clauses 1-9 or the UV curable ink composition of any one of Clauses 10-18, wherein the ink composition has disinfecting properties when exposed to a UV light source.

[0189] Item 20. A synthetic polymer comprising a surface, wherein the surface is coated with at least one coating of the ink composition of any one of items 1-9 or the UV curable ink composition of any one of items 10-18, and the coating provides improved color stability to the synthetic polymer.

[0190] Item 21. A method for disinfecting a surface, wherein the surface is coated with the ink composition of any one of Items 1-9 or the UV-curable ink composition of any one of Items 10-18, the method comprising: exposing the surface to a UV light source, the exposure causing the one or more inorganic phosphor dopants in the ink composition to emit photons; and the photons irradiating the surface, thereby disinfecting the surface.

[0191] Clause 22. The method of Clause 21, wherein the one or more inorganic phosphor dopants emit photons having a wavelength of light between about 200 nm and 280 nm.

[0192] Clause 23. The method of Clause 21 or 22, wherein the one or more inorganic phosphor dopants emit photons having a wavelength of light of about 225 to 250 nm.

[0193] Clause 24. The method of any of Clauses 21-23, wherein the UV light source has a wavelength of about 160 nm to 320 nm.

[0194] Clause 25. The method of any of Clauses 21-24, wherein the UV light source has a wavelength of approximately 222 nm, 254 nm, or 275 nm.

[0195] Item 26. A method for improving the color stability of a synthetic polymer comprising a surface, wherein the surface is coated with the ink composition of any one of Items 1-9 or the UV-curable ink composition of any one of Items 10-18, the method comprising: exposing the surface to UV light, wherein the one or more inorganic phosphor dopants in the ink composition absorb the UV light and then emit the UV light as down-converted visible light.

[0196] Clause 27. The method of Clause 26, wherein the presence of the ink composition coating the surface reduces photo-oxidation of the synthetic polymer.

[0197] Clause 28. The method of Clause 26 or 27, wherein visible light emitted by the one or more inorganic phosphor dopants in the ink composition produces a brighter appearance for the synthetic polymer.

[0198] Clause 29. The method of any one of Clauses 26-28, wherein the ink composition comprises two or more inorganic phosphor dopants, wherein down-converted visible light emitted by the two or more inorganic phosphor dopants combines to produce white or off-white visible light.

[0199] Clause 30. The method of any one of Clauses 26-28, wherein the ink composition comprises three or more inorganic phosphor dopants, wherein down-converted visible light emitted by the three or more inorganic phosphor dopants combines to produce white or off-white visible light.

[0200] Clause 31. The method of any of Clauses 26-30, wherein the UV light absorbed by the one or more inorganic phosphor dopants has a wavelength of about 160 nm to 380 nm.

[0201] Clause 32. The method of any of Clauses 26-31, wherein the synthetic polymer is a thermoplastic or a thermoset.

[0202] Clause 33. The method of any one of Clauses 26-32, wherein the synthetic polymer is selected from the group consisting of tetrafluoroethylene, polyvinyl fluoride, polyurethane, polyester, epoxy resin, phenolic resin, vinyl ester, polyamide, polyamide-imide, polyetherimide, polyvinyl chloride, polyetherketoneketone, polycarbonate, polyphenylsulfone, polymethyl methacrylate, polyacrylate and benzoxazine.

[0203] Item 34. A method of preparing the ink composition of any one of Items 1-9, comprising: contacting a solvent with one or more inorganic phosphor dopants and a binder, thereby preparing the ink composition.

[0204] Item 35. A method of preparing the UV-curable ink composition of any one of Items 10-18, comprising: contacting one or more inorganic phosphor dopants with one or more photoinitiators and one or more monomers, thereby preparing the UV-curable ink composition.

[0205] The following examples are provided by way of illustration and not limitation. It will be appreciated by those skilled in the art that other synthetic routes may be used to synthesize the inorganic phosphor dopant (100) and inorganic phosphor-doped substrates described herein. Although specific raw materials and reagents are described and discussed in the embodiments, other raw materials and reagents may be easily substituted to provide various derivative materials and / or reaction conditions. In addition, many exemplary materials prepared by the method may be further modified according to the present disclosure using conventional chemistry known to those skilled in the art.

[0206] Example

[0207] Example 1: Photon-emitting inorganic phosphor doped ink composition coated substrate (Ca 2-x Al 2 SiO 7 : x Pr 3+ Preparation of doped polyvinyl chloride

[0208] Step 1. Ca 2-x Al 2 SiO 7 : x Pr 3+ Preparation

[0209] CaO、Al 2 O 3 、SiO 2 and Pr 6 O 11 Purchased from Sigma Aldrich. Weigh CaO, Al 2 O3 、SiO 2 and Pr 6 O 11 , so that the mixture Pr 6 O 11 The amount will produce 0.5-5% praseodymium substitution on the calcium site. The powder is then ground using an agate mortar and pestle for about 5 minutes until the powder forms a gray fine mixture. Thereafter, the mixed powder is placed in a ceramic alumina crucible and pre-fired at 900°C in air for 2 hours. Thereafter, the mixed powder is ground in an agate mortar and pestle for about 3 minutes. The mixed powder is then placed back into the alumina crucible and in a furnace for heating at 1300°C in air for 7 hours. The powder is removed from the furnace and allowed to cool to room temperature.

[0210] Powder X-ray diffraction analysis of the prepared Ca 2-x Al 2 SiO 7 : x Pr 3+ Inorganic phosphor dopant (100). FullProf was used to analyze the crystal structure to verify the Ca 2 Al 2 SiO 7 Ca / Pr site mixing in the crystal structure.

[0211] Step 2. Ca 2-x Al 2 SiO 7 : x Pr 3+ Preparation of doped coated substrates

[0212] The Ca prepared in step 1 2-x Al 2 SiO 7 : x Pr 3+ The powder is thoroughly mixed with a solvent (111) and a binder (112) to make Ca 2-x Al 2 SiO 7 : x Pr 3+ and a binder (112) are uniformly incorporated into a solvent (111) to form an ink composition (110). Using a piezoelectric print head, the ink composition (110) is inkjet printed onto a surface (101a) of a main substrate (101) material to form a Ca 2-x Al 2 SiO 7 : x Pr 3+ The doped coated substrate (101) material is then cured.

[0213] Example 2: Substrate material (Ca 2-x Al 2 SiO7 : x Pr 3+ Doped coated substrate) disinfection

[0214] The Ca prepared in step 2 2-x Al 2 SiO 7 : x Pr 3+ The doped coated substrate (101) material is exposed to a UV light source (104) having a wavelength of about 160 nm to 280 nm. This is the Ca in the ink composition (110) coated on the surface (101a) of the host substrate (101) material. 2-x Al 2 SiO 7 : x Pr 3+ The radiation excitation energy of the phosphor. 2-x Al 2 SiO 7 : x Pr 3+ The doped coated substrate (101) material is exposed to a UV light source (104) (e.g., a UV lamp) for about 2 minutes to 10 minutes to allow the Ca 2-x Al 2 SiO 7 : x Pr 3+ The fluorescent body is charged. Then the UV light source (104) is turned off. The Ca coated on the substrate (101) material 2-x Al 2 SiO 7 : x Pr 3+ The phosphor then emits light in the range of 200 nm to 280 nm for about 2 to 10 minutes. This range of light emission corresponds to UV-C light, which is known to kill bacteria. 2-x Al 2 SiO 7 : x Pr 3+ The bactericidal light emitted by the fluorescent body irradiates Ca 2-x Al 2 SiO 7 : x Pr 3+ The surface (101a) of the doped coated substrate (101) material is sterilized, thereby sterilizing the surface (101a). The afterglow intensity of the phosphor-doped substrate (101) material is measured using a spectrofluorometer.

[0215] In another example, the UV light source (104) can be a pulsed xenon UV device or a pulsed xenon lamp having a wavelength of about 222 nm, 254 nm, or 275 nm, which is exposed to the Ca prepared in step 2. 2-x Al 2 SiO 7 : x Pr 3+ In one example, Ca 2-x Al 2 SiO 7 : x Pr 3+ The surface (101a) of the doped coated substrate (101) material is exposed to a UV light source (104) (e.g., a pulsed xenon UV device having a wavelength of 254 nm) for about 2 minutes. When the excitation light is removed, a UV-C continuous luminescence emission at 268 nm is obtained. Ca 2-x Al 2 SiO 7 : x Pr 3+ Pr in the doped coated substrate (101) material 3+ UV-C afterglow shows that Ca 2-x Al 2 SiO 7 : x Pr 3+ The energy wells in the phosphor can be efficiently filled by 254 nm light excitation, and the energy wells are located at appropriate energy positions so that they can be transferred from Pr 3+ 4f 1 5d 1 The electron is effectively trapped in the 4f state and released back to the 4f state due to the ambient thermal stimulation after the excitation stops. 1 5d 1 state. Isotropic light emission effectively 2-x Al 2 SiO 7 : x Pr 3+ The surface (101a) of the doped coated substrate (101) material is sterilized. The afterglow intensity of the phosphor-doped surface (101a) of the substrate (101) material is measured using a spectrofluorometer.

[0216] Example 3: Photon-emitting inorganic phosphor doped coated substrate material (NaY( 1-x )F 6 : x Pr 3+ Preparation of doped tetrafluoroethylene

[0217] Step 1. NaY( 1-x )F 6 : x Pr 3+ Preparation

[0218] Preparation of Cs by solid-state synthesis 2 NaY( 1-x )F 6 : x Pr 3+ (where x = 0.01-0.10) of the nominal composition of Pr doped polycrystalline potassium chloride cryolite phosphor. 2 CO 3 (1.6290 g, 99.99%, Aladdin, Shanghai, China), NaHCO 3 (0.4200 g, 99.99%, Aladdin, Shanghai, China), Y 2 O 3 (0.5588 g, 99.99%, Aladdin, Shanghai, China), NH 4 F (2.2222 g, 99.99%, Aladdin, Shanghai, China) and Pr 6 O 11 (0.0085 g, 99.996%, Alfa, USA) powder was mixed with 3 mL of acetone and then fully ground for about 5 minutes. The resulting powder was heat treated in air at 150°C for 7 hours and then ground again to obtain a fine powder. The mixture was then sintered in air at 450°C for 30 minutes. The resulting powder was then ground again and subsequently sintered at 700°C for 10 hours under a nitrogen atmosphere. A corundum boat with a purity of 99% and a platinum crucible were used as containers for the above synthesis.

[0219] Powder X-ray diffraction analysis of the prepared Cs 2 NaY( 1-x )F 6 : x Pr 3+ Inorganic phosphor dopant (100). FullProf was used to analyze the crystal structure to verify the Cs 2 NaY( 1-x )F 6 : x Pr 3+ The Y / Pr sites in the crystal structure are mixed. The structure crystallizes in the Fm-3m space group corresponding to cubic lysozyme. In this double perovskite structure, both Y and Na are coordinated with 6 boron atoms, and the doped Pr 3+ Ion substitution Y 3+ ion.

[0220] Step 2.Cs 2 NaY( 1-x )F 6 : x Pr 3+ Preparation of doped coated tetrafluoroethylene

[0221] The Cs prepared in step 1 2 NaY( 1-x )F 6: x Pr 3+ The powder is thoroughly mixed with a solvent (111) and a binder (112) to make Cs 2 NaY( 1-x )F 6 : x Pr 3+ and a binder (112) are uniformly incorporated into a solvent (111) to form an ink composition (110). Using a piezoelectric print head, the ink composition (110) is printed onto a surface (101a) of a main substrate (101) material to form a Cs 2 NaY( 1-x )F 6 : x Pr 3+ The ink composition (110) is then cured to form a cured Cs on the surface (101a) of the tetrafluoroethylene substrate (101). 2 NaY( 1-x )F 6 : x Pr 3+ Doped coating.

[0222] Example 4: Using an inorganic phosphor doped coated substrate material (Cs 2 NaY( 1-x )F 6 : x Pr 3+ Doped PTFE-coated sterilization

[0223] The Cs prepared in step 2 2 NaY( 1-x )F 6 : x Pr 3+ The doped coated tetrafluoroethylene substrate (101) material is exposed to a UV light source (104) (e.g., a pulsed xenon lamp) having a wavelength of 100 nm to 225 nm for about 30 seconds. The pulsed light is sufficient to degrade the Cs on the coated surface (101a) of the tetrafluoroethylene substrate (101) material. 2 NaY( 1-x )F 6 : x Pr 3+ The phosphor is charged. Then the Cs 2 NaY( 1-x )F 6 : x Pr 3+ The phosphor emits light (bactericidal light) in the range of 200 nm to 280 nm for about 10 to 20 minutes. 2 NaY(1-x )F 6 : x Pr 3+ The germicidal light emitted by the phosphor irradiates the Cs 2 NaY( 1-x )F 6 : x Pr 3+ The surface (101a) of the doped tetrafluoroethylene substrate (101) material is coated with the doped tetrafluoroethylene substrate (101) material, thereby sterilizing the surface (101a). The afterglow intensity of the phosphor-doped coating of the substrate (101) material is measured using a spectrofluorometer.

[0224] Efforts have been made to ensure accuracy with respect to numbers used (eg amounts, temperature, etc.) but some experimental errors and deviations should be accounted for.

[0225] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein that can be used to practice the subject matter described herein.The present disclosure is in no way limited to the methods and materials described.

[0226] Where a numerical range is provided, unless the context clearly dictates otherwise, it is understood that the upper and lower limits of the range and any other stated value or intervening value in the stated range are included to the tenth of the unit of the lower limit. The upper and lower limits of these smaller ranges, which may be independently included in the smaller ranges, are also included, subject to any specifically excluded limits in the stated range. Where the stated range includes one or both of these limits, then ranges excluding one or both of those included limits are also included.

[0227] Benefiting from the teachings presented in the foregoing description and the related drawings, those skilled in the art of these disclosures will think of many modifications and other examples of the disclosures set forth herein. Therefore, it should be understood that the present disclosure is not limited to the specific examples disclosed, and modifications and other examples are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the related drawings describe examples in the context of certain example combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative examples without departing from the scope of the appended claims. In this regard, for example, as may be set forth in some of the appended claims, combinations of elements and / or functions different from those explicitly described above are also contemplated. Although specific terms are employed herein, they are used only in a general and descriptive sense, and not for the purpose of limitation.

Claims

1. An ink composition comprising: one or more inorganic phosphor dopants; Solvents; and Adhesive.

2. The ink composition according to claim 1, wherein The one or more inorganic phosphor dopants have a diameter no greater than 0.5 μm.

3. The ink composition according to claim 1 or 2, wherein The one or more inorganic phosphor dopants are each independently selected from the group consisting of metal oxides and metal fluorides containing rare earth ions, wherein the rare earth ions are selected from Pr 3+ 、Ce 3+ 、Eu 3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof, or optionally, the rare earth ion is Pr 3+ , and / or the metal oxides are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides and aluminates or combinations thereof.

4. The ink composition according to any one of claims 1 to 3, wherein The solvent is selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, 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 any one of claims 1 to 4, wherein The binder is selected from the group consisting of ethyl cellulose, polymethyl methacrylate, polyurethane, latex, polydimethylsiloxane, polyvinyl alcohol, vinyl chloride / vinyl acetate copolymer, acrylic and polyketone.

6. The ink composition according to claim 1, wherein The ink composition has a viscosity of about 2 mPa-s to about 30 mPa-s, and / or optionally, the ink composition is formulated as an aerosol spray.

7. A method for preparing the ink composition according to any one of claims 1 to 6, comprising: The ink composition is prepared by contacting a solvent with one or more inorganic phosphor dopants and a binder.

8. A UV curable ink composition comprising: one or more inorganic phosphor dopants; one or more photoinitiators; and One or more monomers.

9. The UV curable ink composition according to claim 8, wherein: The one or more inorganic phosphor dopants have a diameter no greater than 0.5 μm.

10. The UV curable ink composition according to claim 8 or 9, wherein: The one or more inorganic phosphor dopants are each independently selected from the group consisting of metal oxides and metal fluorides containing rare earth ions, wherein the rare earth ions are selected from Pr 3+ 、Ce 3+ 、Eu 3+ 、Eu 2+ , Gd 3+ , Tb 3+ and Dy 3+ or a mixture thereof.

11. The UV curable ink composition according to claim 10, wherein: The rare earth ion is Pr 3+ .

12. The UV curable ink composition according to claim 10 or 11, wherein The metal oxides are each selected from the group consisting of silicates, phosphates, borates, oxides, oxynitrides, oxysulfides, and aluminates, or combinations thereof.

13. The UV curable ink composition according to any one of claims 7 to 12, wherein: The 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), benzyl dimethyl ketal (BDK, Irgacure 651), 2-hydroxy-methyl-1-phenylpropane (Darocure 1173), hydroxycyclohexyl phenyl ketone (HCPK, Irgacure 184), Irgacure 907, Irgacure 369, monoacylphosphine oxide (Lucerin TPO), Esacure KIP150, monoacylphosphine oxide (MAPO) and bisacylphosphine oxide photoinitiator (BAPO).

14. The UV curable ink composition according to any one of claims 8 to 13, wherein The one or more monomers are each independently an acrylate monomer.

15. The UV curable ink composition according to any one of claims 8 to 14, further comprising one or more additives for reducing surface tension and / or improving substrate wetting.

16. The UV curable ink composition according to any one of claims 8 to 15, wherein The UV curable ink composition has a viscosity of about 5 mPa-s to about 35 mPa-s.

17. A synthetic polymer comprising a surface wherein: The surface is coated with at least one coating of the UV curable ink composition of any one of claims 8-16, and the coating provides improved color stability to the synthetic polymer.

18. A method for preparing the UV curable ink composition according to any one of claims 8 to 17, comprising: The UV curable ink composition is prepared by contacting one or more inorganic phosphor dopants with one or more photoinitiators and one or more monomers.

19. The ink composition according to any one of claims 1 to 6 or 8 to 16, wherein The ink composition has disinfecting properties when exposed to a UV light source.

20. A method for improving the color stability of a synthetic polymer comprising a surface, wherein: The surface is coated with the ink composition of any one of claims 1 to 6 or the UV curable ink composition of any one of claims 8 to 16, and the method comprises: exposing the surface to UV light, wherein the one or more inorganic phosphor dopants in the ink composition absorb the UV light and then emit the UV light as down-converted visible light.

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