Unsaturated trithiocyanurate derivatives for curable high refractive index compositions, articles thereof, and methods of making such articles

Abstract

Described herein is a curable ink composition derived from at least one unsaturated trithiocyanurate derivative according to formula (I) wherein R1, R2 and R3 each independently comprise a terminal olefin or a terminal alkyne; and at least one multifunctional thiol, wherein the curable ink composition is substantially free of solvent. These curable ink compositions may be inkjet printable and have a refractive index of at least 1.70 when cured (when measured at 450 nm).

Description

Technical Field

[0001] This document discloses unsaturated trithiocyanurate derivatives that are reacted in thiol-alkene and / or thiol-acetylene reactions to obtain compositions having high refractive indices. Curable compositions and articles thereof for use in, for example, optical devices are also disclosed. Summary of the Invention

[0002] In the display industry, a series of alternating organic and inorganic layers (called thin-film encapsulation, TFE) are used on top of optical displays (such as organic light-emitting devices (OLEDs) or quantum dot films) to protect the underlying display and enhance its performance, such as providing flexible panels. However, these layers must perform multiple functions, including acting as a barrier to protect the underlying optical display from external environmental factors such as moisture and air, and minimizing harmful optical properties.

[0003] In thin-film encapsulation, the inorganic layer functions to prevent air and moisture from entering the underlying optical components. The organic layer serves a dual function: 1) to planarize the substrate and create a smooth interface for depositing the inorganic layer; and 2) to decouple any defects (pinholes, microcracks) that may occur in the inorganic layer on either side of the organic layer. The organic layer can be considered a buffer layer that is crucial for the successful barrier function of the inorganic layer.

[0004] The aim is to identify curable compositions with low viscosity that can be inkjet printed and produce organic layers with high refractive index.

[0005] In one aspect, a curable ink composition is described, the curable ink composition comprising: At least one unsaturated trithiocyanurate derivative according to formula (I)

[0006] Where R 1 R 2 and R 3 Each independently includes terminal olefins or terminal alkynes; and

[0007] At least one polyfunctional thiol, wherein the polyfunctional thiol is an aromatic thiol or a non-aromatic thiol having a liquid refractive index of at least 1.62. The curable ink composition is substantially solvent-free.

[0008] In another aspect, an article is disclosed. The article comprises (i) a substrate having a first main surface and a second main surface; and (ii) a cured organic layer adjacent to at least a portion of the second main surface of the substrate, wherein the cured organic layer is derived from at least one unsaturated trithiocyanurate derivative according to formula (I).

[0009] Where R 1 R 2 and R 3 Each independently includes terminal olefins or terminal alkynes; and

[0010] At least one polyfunctional thiol; and

[0011] (iii) An inorganic barrier layer in contact with the cured organic layer, wherein the cured organic layer has a refractive index of at least 1.70 as measured at 450 nm.

[0012] In another aspect, a method for preparing an article of articles is described. The method includes: A substrate having a first main surface and a second main surface is provided; A curable ink composition is provided, the curable ink composition comprising at least one unsaturated trithiocyanurate derivative according to formula (I).

[0013] Where R 1 R 2 and R 3 Each of the following independently includes a terminal olefin or a terminal alkyne; and at least one polyfunctional thiol; The curable ink composition is set in A curable layer is formed on at least a portion of the second main surface of the substrate; The curable layer is cured to form a cured organic layer, wherein the cured organic layer has a refractive index of at least 1.70 measured at 450 nm; and An inorganic barrier layer is deposited on the cured organic layer.

[0014] The above description is not intended to illustrate every embodiment. Details of one or more embodiments of the invention are also set forth in the following detailed description. Other features, objectives, and advantages will become apparent from this specification and the claims. Attached Figure Description

[0015] This application can be more fully understood by referring to the following detailed description of various embodiments of this disclosure in conjunction with the accompanying drawings.

[0016] Figure 1 A cross-sectional view of an embodiment of the article of manufacture disclosed herein is shown.

[0017] Figure 2 A cross-sectional view of an embodiment of another article of the present disclosure is shown.

[0018] In the following description of the illustrated embodiments, reference is made to the accompanying drawings, in which various embodiments in which this disclosure may be practiced are shown by way of example. It should be understood that embodiments may be utilized and structural changes may be made without departing from the scope of this disclosure. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar components. However, it should be understood that the use of numbers to refer to parts in a given drawing is not intended to limit parts labeled with the same numbers in another drawing. Detailed Implementation

[0019] As used in this article, terminology

[0020] “A,” “an,” and “the” are used interchangeably and refer to one or more; and

[0021] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0022] Furthermore, in this document, the ranges expressed by the endpoints include all numbers contained within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0023] Furthermore, in this document, the expression "at least one" includes all numbers that are one or greater than one (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0024] The terms “room temperature” and “ambient temperature” are used interchangeably and have their usual meanings, referring to a temperature between 20°C and 25°C.

[0025] As used herein, the term "adjacent" refers to two floors that are adjacent to each other. Adjacent floors may be in direct contact with each other, or there may be an intervening floor. There is no blank space between adjacent floors.

[0026] As used in this article, "containing at least one of A, B, and C" means containing only element A, containing only element B, containing only element C, containing both A and B, containing both A and C, containing both B and C, and combinations containing all three.

[0027] In this disclosure, it has been found that low-viscosity curable compositions comprising unsaturated trithiocyanurate derivatives and polyfunctional thiols can produce cured compositions with high refractive index and optionally high glass transition temperature (Tg).

[0028] The curable compositions disclosed herein are substantially solvent-free and comprise at least one polyfunctional thiol and at least one unsaturated trithiocyanurate derivative according to formula (I).

[0029] The compound according to formula (I) is

[0030] Where R 1 R 2 and R 3 Independently includes a terminal carbon-carbon double bond (i.e., a monovalent alkene) or a terminal carbon-carbon triple bond (i.e., a monovalent alkyne). Exemplary monovalent alkenes include: -CH2CH=CH2, -CH2CH2CH=CH2, -CH2CH2CH2CH=CH2, -CH2CCH3=CH2, and -CH2(phenyl)CH=CH2 (when the phenyl group is a divalent 6-membered aromatic ring). Exemplary monovalent alkynes include: -CH2C≡CH, -CH2CH2C≡CH, -CH2CH2C≡CH, -CH2CH2CH2C≡CH, and -CH2(phenyl)C≡CH. In some embodiments, R 1 R 2 and R 3 It is the same, while in other implementations, R 1 R 2 and R 3 They are different. Exemplary unsaturated trithiocyanurate derivatives according to formula (I) include... And their mixtures.

[0031] The polyfunctional thiols disclosed herein comprise at least two thiol (i.e., -SH) groups, although they may have more than two thiol groups, such as three, four, or even five thiol groups. The polyfunctional thiols of this disclosure may comprise aromatic or non-aromatic thiols. In some embodiments, the polyfunctional thiols are liquid under ambient conditions, in other words, at room temperature and 1 atmosphere. In some embodiments, the polyfunctional thiols of this disclosure have melting points at ambient pressure (e.g., 760 mm Hg) below 80°C, 70°C, 60°C, 50°C, 40°C, or even 30°C.

[0032] In some embodiments, the polyfunctional thiol is a non-aromatic thiol having a liquid refractive index of at least 1.620, 1.625, 1.630, 1.635, 1.640, 1.650, 1.655, or even 1.660, as measured by a white light refractometer. Typically, the refractive index of non-aromatic polyfunctional thiols does not exceed 1.71 or even 1.70. Exemplary non-aromatic polyfunctional thiols that may have a refractive index of at least 1.620 include: 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane; 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane; 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane; and 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane. Other non-aromatic polyfunctional thiols include: poly(ethylene glycol) dithiol; 1,2,3-trimercaptopropane; 2,3-bis-2-mercaptoethylthio-1-propanethiol; 1,2-ethanedithiol; 2,2'-thiodiethanedithiol; di(mercaptoethyl) sulfide; 2,5-bis(mercaptomethyl)-1,4-disulfide cyclopentane; tetra(ethylene glycol) dithiol; 2,2'-(ethylenedioxy)diethanedithiol;

[0033] Most (if not all) of the latter type of non-aromatic polyfunctional thiols have a liquid refractive index of less than 1.620. However, these non-aromatic polyfunctional thiols, in addition to those with a refractive index of at least 1.620, and / or in addition to aromatic polyfunctional thiols, can be used to improve the solubility of the components in the curable composition. However, care should be taken to minimize the amount of these lower refractive index materials in order to maintain a high refractive index in the finished product.

[0034] In some embodiments, the polyfunctional thiol is an aromatic thiol. Aromatic thiols can have a high refractive index, thereby contributing to the production of cured compositions with a high refractive index. Exemplary aromatic polyfunctional thiols include: 1,3-benzenedithiol; toluene dithiol; 1,3-benzenedimethylthiol; 1,3,4-thiadiazole-2,5-dithiol; (1,2,4)thiadiazole-3,5-dithiol; 1,3,5-trimercaptobenzene; 2-thiazoline-2-thiol; 1,1',4',1"-terphenyl-4-thiol; 5-bromopyridine-2-thiol; biphenyl-4-thiol; 1,7-naphthalenedithiol; and 1,5-naphthalenedithiol.

[0035] The aforementioned unsaturated trithiocyanurate derivative and polyfunctional thiol are reacted in a so-called thiol-alkene or thiol-alkynyl reaction, depending on whether the unsaturated trithiocyanurate derivative is an alkene or an alkyne. Typically, sufficient amounts are used to react the unsaturated trithiocyanurate derivative and the polyfunctional thiol derivative to ensure that no residual reactive groups remain in the cured product. The terminal double bond reacts with one thiol, while the terminal alkyne reacts with two thiols. Therefore, ideally, the molar ratio of the terminal double bond in formula (I) to the thiol group in the polyfunctional thiol compound should be 1:1, and in the case of a triple bond in formula (I), the molar ratio of the terminal alkyne bond to the thiol group should be 1:2. In some embodiments, the molar ratio of the terminal CC double bond in formula (I) to the thiol (-SH) in the polyfunctional thiol compound is 0.8:1 to 1:0.8 or even 0.9:1 to 1:0.9. In some embodiments, the molar ratio of the terminal C-C triple bond in formula (I) to the thiol in the polyfunctional thiol compound is 1.6:1 to 2:0.8 or even 1.8:1 to 2:0.9.

[0036] In some embodiments, the thiol-ene and thiol-yne reactions in the curable compositions of this disclosure consist of or are substantially composed of unsaturated trithiocyanurate derivatives of formula (I) as reactants providing unsaturated (i.e., -ene and / or -yne) groups. Therefore, apart from polyfunctional thiols, the curable compositions of this disclosure may be substantially free of (e.g., contain less than 5 wt%, 2 wt%, 1 wt%, 0.5 wt%, or even 0.1 wt%, or even free of) any monomers containing at least two terminal unsaturated groups other than those of formula (I).

[0037] When preparing a curable composition, the composition is substantially solvent-free. As used herein, “substantially solvent-free” means a curable composition having less than 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, or even 0.5 wt% of a nonpolymerizable (e.g., organic) solvent. The concentration of the solvent can be determined by known methods, such as gas chromatography (e.g., as described in ASTM D5403-93). It should be noted that whether a curable composition is substantially solvent-free or solvent-free, no solvent is intentionally added to the composition. The term “solvent” as used herein is consistent with the commonly understood technical terminology and covers volatile organic and organic materials that are liquid at room temperature.

[0038] In some embodiments, the curable composition comprises at least one free radical initiator. Typically, the initiator is a photoinitiator, meaning that the initiator is activated by light, typically ultraviolet (UV) light, but other light sources may be used depending on the appropriate selection of the initiator (such as visible light initiators, infrared light initiators, etc.). Thus, the curable composition can generally be cured by UV or visible light, typically UV light. Photoinitiators are known in the art. Examples of suitable free radical photoinitiators include OMNIRAD 4265, OMNIRAD 184, OMNIRAD 651, OMNIRAD 1173, OMNIRAD 819, OMNIRAD TPO, and OMNIRAD TPO-L, which are commercially available from IGM Resins, Charlotte, NC, North Carolina. Particularly suitable photoinitiators include those characterized by high absorbance above 365 nm wavelengths. These photoinitiators include the acylphosphine oxide family of photoinitiators, such as OMNIRAD TPO, OMNIRAD TPO-L, and OMNIRAD819.

[0039] If an initiator is used, it is typically used in amounts of 0.01 to 10 parts by weight, more typically 0.1 to 2.0 parts by weight, relative to the total reactive components (i.e., thiols, alkenes, and ynees) in 100 parts by weight of the curable composition.

[0040] In some embodiments, the curable composition may include additional, optional non-curable components, provided that such components do not impede the curing of the curable composition and do not adversely affect the properties of the cured composition. As needed or desired, the curable composition may also contain polymerization inhibitors, UV absorbers, light stabilizers (e.g., hindered amine light stabilizers (HALS)), adhesion promoters, sensitizers, synergists, antioxidants, catalysts, dispersants, desiccants, surfactants, leveling agents, etc.

[0041] A particularly suitable optional additive for the curable compositions disclosed herein is an adhesion promoter. Adhesion promoters are used as additives or as primers to promote adhesion between the cured composition and adjacent layers. Suitable adhesion promoters include silane-functionalized compounds, titanates, and zirconates. Examples of suitable titanates and zirconates include titanium butoxide or zirconium butoxide. Typically, if used, adhesion promoters comprise silane-functionalized compounds. Sometimes silane-functionalized adhesion promoters are called coupling agents because they have different functional groups at each end of the compound and are therefore suitable for coupling different surfaces, such as inorganic and organic surfaces. Examples of silane adhesion promoters include (meth)acrylate-functionalized alkoxysilanes such as SILQUESTA-174, octadecyltrimethoxysilane, isooctyltrimethoxysilane, hexadecyltrimethoxysilane, hexyltrimethoxysilane, methyltrimethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, aminopropyltrimethoxysilane, and 3-propenyloxypropyltrimethoxysilane, from Momentive Performance Materials.

[0042] In some embodiments, the curable composition further comprises polymerization inhibitors and / or heat stabilizers. Typically, these polymerization inhibitors and / or heat stabilizers are added to the curable composition in amounts from 1 mM to 1 M. Exemplary inhibitors include BHT (2,6-di-tert-butyl-p-cresol), MEHQ (4-methoxyphenol), and pyrogallol. Exemplary heat stabilizers include 4-methoxyphenol, pyrogallol, or 4-tert-butyl-1,2-dihydroxybenzene. Acidic compounds may also be used as co-stabilizers, including benzoic acid, benzenesulfonic acid, phenylphosphonic acid, and vinylphosphonic acid. Typical concentrations of co-stabilizers in curable compositions range from 1 mM to 1 M. Available antioxidants include, but are not limited to, amines such as N-N'-di-β-naphthyl-1,4-phenylenediamine, available under "AGERITE D"; phenols such as 2,5-di(tert-amyl)hydroquinone, available under "SANTOVAR A" from Monsanto Chemical Co.; tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, available under "IRGANOX 1010" from Ciba-Geigy Corp.; and 2-2'-methylenebis(4-methyl-6-tert-butylphenol), available under Antioxidant 2246; and dithiocarbamates such as zinc dithiobutylcarbamate.

[0043] Advantageously, the unsaturated trithiocyanurate derivatives according to formula (I) have a high refractive index, which, when used with high-refractive-index polyfunctional thiols, produces a curable composition and ultimately a cured product with a high refractive index. In some embodiments, the curable composition has a refractive index of at least 1.630 when measured by refractive index methods (e.g., ASTM D1218-21).

[0044] In some embodiments, the curable composition has a viscosity of 30 centipoise (cP) or less at temperatures from room temperature to approximately 60°C. In some embodiments, the curable composition has a viscosity of at least 1 cp, 2 cp, 3 cp, 4 cp, or even 5 cp at room temperature; and at most 30 cp, 25 cp, 20 cp, 15 cp, or even 10 cp. In some embodiments, the curable composition has a viscosity of at least 1 cp, 2 cp, 3 cp, 4 cp, or even 5 cp at 35°C; and at most 30 cp, 25 cp, 20 cp, 15 cp, or even 10 cp. In some embodiments, the curable composition has a viscosity of at least 1 cp, 2 cp, 3 cp, 4 cp, or even 5 cp at 60°C; and at most 30 cp, 25 cp, 20 cp, 15 cp, or even 10 cp, as measured by a viscometer under ambient conditions. For example, viscosity can be measured by taking 17 mL of the curable composition and loading it into a 25 mm diameter double-gap coaxial concentric cylindrical apparatus on a viscometer (BOHLIN VISCO 88, Malvern Instruments Ltd, Malvern, UK). Water heated to 25°C can be recirculated in a thermal jacket on the viscometer's double-gap chamber to maintain a constant temperature during testing. For example, the system can be equilibrated for 30 minutes before each measurement. The shear rate can be increased from 100 Hz to 1000 Hz in 100 Hz intervals, and the measurement is repeated three times to determine the average viscosity.

[0045] Curable compositions can be deposited onto surfaces using techniques known in the art, including conventional coating techniques such as bar coating, roll coating, curtain coating, rotary gravure coating, spraying, or dip coating. The curable compositions disclosed herein can be used, in particular, as organic layers in thin-film encapsulation components. Typically, printing techniques such as inkjet printing are used to deposit these organic layers.

[0046] A variety of substrates are suitable for the articles of manufacture disclosed herein. Suitable substrates include a wide range of flexible and non-flexible substrates. For example, the substrate may be glass or a relatively thick layer of polymeric material, such as PMMA (polymethyl methacrylate) or PC (polycarbonate). Alternatively, the substrate may be a flexible polymer film, such as a film of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), polyimide, PEEK (polyetheretherketone), etc. In some embodiments, the substrate includes a thermosensitive substrate. A variety of thermosensitive substrates are suitable, such as OLED panels.

[0047] Curable compositions can be exposed to thermal or light radiation to initiate a reaction between thiols and carbon-carbon double or triple bonds of formula (I), resulting in a cured composition. Curable compositions can be exposed to ultraviolet (UV)A radiation with a maximum value in the range of 280 nm to 425 nm. UV light sources can be of various types. Low-intensity light, such as blacklights, typically provides intensities ranging from 0.1 mW / cm² or 0.5 mW / cm² (mW / cm²) to 10 mW / cm² (measured according to procedures approved by the National Institute of Standards and Technology, such as, for example, using a UVIMAP UM365 LS radiometer manufactured by Electronic Instrumentation & Technology, Inc., Sterling, VA). High-intensity light sources typically provide intensities greater than 10 mW / cm², 15 mW / cm², or 20 mW / cm², ranging up to 450 mW / cm² or greater. In some implementations, the high-intensity light source provides intensities up to 500 mW / cm², 600 mW / cm², 700 mW / cm², 800 mW / cm², 900 mW / cm², or 1000 mW / cm². The UV light used to polymerize these monomer components can be provided by a variety of light sources, such as light-emitting diodes (LEDs), black lights, medium-pressure mercury lamps, or combinations thereof. The reagents can also be polymerized using even higher-intensity light sources available from Fusion UV Systems Inc. The UV exposure time for polymerization and curing can vary depending on the intensity of the light source used. For example, complete curing using low-intensity light can be completed with an exposure time ranging from approximately 30 to 300 seconds; while complete curing using a high-intensity light source can be completed with a shorter exposure time ranging from approximately 5 to 20 seconds. Partial curing using a high-intensity light source can typically be completed with an exposure time ranging from approximately 2 to approximately 5 or 10 seconds.

[0048] In some embodiments, it is preferable to use light that emits a narrow spectrum in the ultraviolet region of the electromagnetic spectrum. These light sources (which may include LEDs and lasers) can lead to the formation of a cured composition without the need for conventional initiators prior to the curing process. These light sources can increase the polymerization rate while maintaining the active properties of the polymer material.

[0049] In other embodiments, where a wider wavelength of ultraviolet light source (such as a black light) is used, it may be necessary to add a conventional photoinitiator to the curable composition before crosslinking.

[0050] Typically, the cured layer has a refractive index of at least 1.700, 1.710, 1.720, 1.730, 1.740, 1.750, 1.760, 1.770, or even 1.780 when measured at 450 nm. High-refractive-index nanoparticles, such as polymer particles, metal particles, or metal oxide particles having a refractive index of at least 1.6, are commonly used to increase the refractive index of the cured layer. However, advantageously, the cured composition of this disclosure has a high refractive index without the use of nanoparticles.

[0051] In some embodiments, the cured composition has a glass transition temperature of at least 10°C, 20°C, 30°C, 40°C, 45°C, 50°C, or even 54°C, and at most 120°C, 110°C, 100°C, 90°C, or even 80°C. The terms "Tg" and "glass transition temperature" are used interchangeably. If measured, unless otherwise specified, the Tg value is determined by differential scanning calorimetry (DSC) at a scan rate of 10°C / min.

[0052] Ideally, the cured composition is optically transparent. Unless otherwise specified, "optically transparent" means that the layer, film, or article has high transmittance and exhibits low haze over at least a portion of the visible spectrum (about 400 nm to about 700 nm). Typically, using techniques such as ASTM D1003-21, an optically transparent layer, film, or article has a visible light transmittance value of at least 85%, or even 90%, typically at least 95%, and a haze value of 5% or less, typically 2% or less.

[0053] This document also discloses articles. A wide variety of articles can be prepared using the above-described curable composition. The articles can be relatively simple, such as... Figure 1The illustrated substrate has a layer of cured composition disposed thereon, wherein article 100 includes a substrate 120 and a cured organic layer 110 disposed on the substrate. Substrate 120 includes a wide variety of flexible and non-flexible substrates. For example, substrate 120 may be a layer of glass, silicon nitride, silicon oxynitride, or a relatively thick polymeric material such as PMMA (polymethyl methacrylate) or PC (polycarbonate). Alternatively, substrate 120 may be a flexible polymeric film, such as a film of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), polyimide, PEEK (polyetheretherketone), etc. The cured organic layer 110 is a cured layer derived from the curable composition described herein. In some embodiments, the cured organic layer has a thickness of 1 micrometer to 50 micrometers, and in some embodiments, 5 micrometers to 30 micrometers.

[0054] In other embodiments, the article is more complex, such as a multilayer article comprising a substrate and an inorganic barrier layer, wherein a cured organic layer is interposed therebetween, wherein the cured layer serves as a decoupling layer. The substrate may optionally have an inorganic coating present on its surface, such that the cured organic layer may contact the substrate surface or the optional inorganic coating.

[0055] In some embodiments, the article includes a substrate having a first main surface and a second main surface, and a cured organic layer having a first main surface and a second main surface, wherein the first main surface of the cured organic layer is adjacent to at least a portion of the second main surface of the substrate.

[0056] Figure 2 Devices incorporating the multilayer articles of this disclosure are shown. Figure 2 An article 200 including a substrate 230 is shown, and a device 240 is disposed on the substrate 230. An inorganic barrier layer 250 is in contact with the device 240, and a cured organic layer 210 is in contact with the inorganic barrier layer 250. Figure 2 It also includes an optional inorganic layer 260 that contacts the cured organic layer 210. An optional layer 270 contacts the optional inorganic layer 260 and also contacts the substrate 280. Additionally, optional alternating pairs of cured organic layers (210) and inorganic layers (260) may exist between the optional layers 260 and 270. For clarity, these optional layers are not shown, but a stack of layers in the order 250 / 210 / 260 / 210 / 260 or 250 / 210 / 260 / 210 / 260 / 210 / 260, etc., can be readily imagined.

[0057] The curable compositions disclosed herein can be cured and used as organic layers in thin-film encapsulation components. These organic layers should be deposited onto a surface in a precise and consistent manner, which is typically accomplished using printing techniques. In printing techniques, the curable composition, which forms a polymer upon curing, is printed onto a substrate surface to form a layer. A wide variety of printing techniques can be used, with inkjet printing being particularly desirable due to its excellent precision. Because curable compositions can be printable, they may also be referred to herein as inks. Curable compositions are not necessarily used as inks, that is, they are not necessarily printed and then cured; curable compositions can be delivered to a substrate surface in a wide variety of ways, but they are printable. Specifically, the printable compositions of this disclosure are generally inkjet printable, meaning that they have suitable viscosity and other properties required for inkjet printing. The term "inkjet printable" is not a process description or limitation, but a material description, meaning that the curable composition can be inkjet printed, not that the composition must have been inkjet printed. In this disclosure, printable curable compositions, which can be considered "inks," are described, and these curable compositions have several characteristics that make them suitable for forming layers within multilayer optical devices. As described above, the curable compositions of this disclosure are substantially solvent-free, which is advantageous because drying the coating to remove solvent not only reduces the layer thickness but also adversely affects surface smoothness and may introduce defects into the coating. In many applications of optical devices, it is desirable for coatings to be precise, meaning they do not lose thickness or smoothness during drying. Therefore, the curable compositions of this disclosure are preferably “100% solids,” meaning they do not contain volatile solvents and all substances deposited on the surface remain on the surface, with no volatile substances lost from the coating.

[0058] The thickness of the cured composition is limited by the application. For thin-film encapsulated products, the cured organic layer typically has a thickness of 1 micrometer to 50 micrometers, and in some embodiments 5 micrometers to 30 micrometers. Additionally, in many embodiments, the cured organic layer has a surface roughness of less than or equal to 10 nanometers, and in some embodiments less than or equal to 5 nanometers.

[0059] An example of an optical device utilizing thin-film layers is an OLED (Organic Light-Emitting Diode) device. Specifically, OLEDs are susceptible to degradation due to the permeation of certain liquids and gases, such as water vapor and oxygen. To reduce permeability to these liquids and gases, a barrier coating is applied to the OLED device. Typically, these barrier coatings are not used alone, but rather in a barrier stack comprising multiple pairs of layers. A pair of layers is a two-layer structure comprising a barrier layer (i.e., an inorganic layer) and a decoupling layer (i.e., an organic layer). The decoupling layer provides a planarized and / or smooth surface for depositing the inorganic barrier layer.

[0060] The inorganic barrier layer 250, in contact with the cured organic layer 210, can be made of a variety of materials, including metals, metal oxides, metal nitrides, metal oxide nitrides, metal carbides, metal boron oxides, and combinations thereof. A wide range of metals are suitable for metal oxides, metal nitrides, and metal oxide nitrides; specifically, suitable metals include Al, Zr, Si, Zn, Sn, and Ti. A particularly suitable inorganic barrier layer material is silicon nitride.

[0061] There is no specific limitation on the thickness of the inorganic barrier layer 250, which is typically between 20 nanometers and 1 micrometer (1000 nanometers). More typically, the thickness is between 20 nanometers and 100 nanometers.

[0062] The optional inorganic barrier layer 260 has a similar thickness to the inorganic barrier layer 250 and may contain the same inorganic material, or it may be a different inorganic material.

[0063] One embodiment of device 200 is a touch sensing device. In this device, substrate 230 is a thin-film transistor, device 240 is an OLED device, optional layer 270 is an optically transparent adhesive layer, and substrate 280 is a touch sensor.

[0064] In some embodiments, a curable composition is applied to the surface of a substrate and then cured to form a cured organic layer. In some embodiments, an inorganic barrier layer is disposed on the exposed surface of the cured organic layer.

[0065] In some embodiments, the curable composition can be printed and then cured to form a layer. In some embodiments, the cured composition has a thickness of 1 micrometer to 16 micrometers and a surface roughness of less than or equal to 5 nanometers. In many embodiments, setting the curable composition on a second primary surface of a substrate to form a curable layer includes printing, particularly inkjet printing. As mentioned above, inkjet printing has several desirable characteristics that make it particularly suitable for preparing curable layers, including the ability to deposit precise patterns on complex substrates and form a uniform coating with a low surface roughness of less than 10 nanometers, and in some embodiments less than or equal to 5 nanometers.

[0066] In some embodiments, the article also includes a device disposed on a second main surface of the substrate and adjacent to the cured organic layer.

[0067] In some embodiments, the substrate includes an inorganic coating present on a second primary surface, such that the first primary surface of the cured organic layer is in contact with the inorganic coating.

[0068] The above-described structure can also be used as a component of more complex articles. In some embodiments, the article further includes a device disposed on a second main surface of the substrate and adjacent to the first main surface of the cured organic layer. In some embodiments, an inorganic coating is disposed on the device and the second main surface of the substrate, such that the first main surface of the cured organic layer is in contact with the inorganic coating. In some specific embodiments, the device includes an OLED (organic light-emitting diode).

[0069] Example

[0070] Unless otherwise specified, all parts, percentages, ratios, etc., in the examples and the remainder of the description are by weight, and all reagents used in the examples are derived from or purchased from common chemical suppliers, such as, for example, Millipore-Sigma Company, Saint Louis, Missouri, or can be synthesized by conventional methods.

[0071]

[0072] Preparation of T3

[0073] Ethanol (130 mL) was added to a solution of water (30 mL) and potassium hydroxide (10.13 g, 0.18 mol). While cooling in a water bath, 1,3,5-triazine-2,4,6-trithione (10.00 g, 0.056 mol) was slowly added over five minutes. The mixture was stirred for 30 minutes until the solid dissolved. Then, allyl bromide (27.42 g, 0.23 mol) was added. The reaction mixture was warmed to 40 °C and stirred at room temperature for three hours. The mixture was then concentrated under vacuum. Ethyl acetate (150 mL) and water (100 mL) were added, and the organic phase was separated and concentrated under vacuum. The crude product was purified by silica gel column chromatography (gradient from 0 v / v to 20 v / v ethyl acetate in hexane). The final product was separated as a pale green / yellow oil (13.514 g).

[0074] Preparation of TPATTC

[0075] Solid sodium metal (2.34 g, 0.102 mol) was added to ethanol (120 mL). The mixture was stirred until the solid was completely dissolved. Then, 1,3,5-triazine-2,4,6-trithione (6.00 g, 0.034 mol) was added in portions over five minutes. The mixture was stirred for thirty minutes until the solid was dissolved. Then, propargyl bromide (20.00 g in 80 wt% toluene solution, 0.134 mol) was added, and the mixture was stirred at room temperature for seventeen hours. The mixture was then concentrated under vacuum. Ethyl acetate (150 mL) and water (100 mL) were added, and the organic phase was separated and concentrated under vacuum. The crude product was purified by silica gel column chromatography (gradient from 0 vol% to 20 vol% ethyl acetate in hexane). The final product was separated as a pale yellow solid (5.27 g).

[0076] Preparation of mixed triallyl / propargyl thiocyanurate (mixed TA / P TCU)

[0077] Solid sodium metal (3.89 g, 0.169 mol) was added to ethanol (130 mL). The mixture was stirred until the solid was completely dissolved. Then, 1,3,5-triazine-2,4,6-trithione (10.00 g, 0.056 mol) was added in portions over five minutes. The mixture was stirred for thirty minutes until the solid was dissolved. Then, a mixture of allyl bromide (7.50 g, 0.062 mol) and propargyl bromide (18.45 g in 80% toluene solution, 0.124 mol) was added, and the mixture was stirred at room temperature for three hours. The mixture was then concentrated under vacuum. Ethyl acetate (150 mL) and water (100 mL) were added, and the organic phase was separated and concentrated under vacuum. The crude product was purified by silica gel column chromatography (5% to 30% ethyl acetate / hexane gradient). The final product was separated as a pale yellow waxy solid (13.39 g) with a total composition of 32% allyl and 68% propargyl substitution.

[0078] Preparation of tri(vinylbenzyl)thiocyanurate (TVBTCU)

[0079] Solid sodium metal (3.11 g, 0.135 mol) was added to ethanol (130 mL). The mixture was stirred until the solid was completely dissolved. Then, 1,3,5-triazine-2,4,6-trithione (8.00 g, 0.045 mol) was added in portions over five minutes. The mixture was stirred for thirty minutes until the solid was dissolved. Then, chloromethylstyrene (a mixture of p and m isomers, 21.00 g, 0.138 mol) was added, and the mixture was stirred at 50 °C for seventeen hours. The mixture was then concentrated under vacuum. Ethyl acetate (100 mL) and water (100 mL) were added, and the solid product was filtered. The solid product was dissolved in dichloromethane (300 mL) and dried over magnesium sulfate. The mixture was filtered and concentrated under vacuum to give a final product (14.28 g) as a brown solid.

[0080] Test methods

[0081] Refractive index of liquid composition

[0082] The refractive index was measured on a refractometer (Milton Roy Company, Ivyland, PA). The liquid sample was sealed between two prisms, and the refractive index was measured at 20°C using the 589 nm line of "white light" from a sodium lamp.

[0083] Refractive index of the cured film

[0084] The refractive index of a cured ink film on a PET substrate was measured at 450 nm at 20°C using a digital prism coupler (model 2010, Metricon Inc., Pennington, NJ).

[0085] Differential scanning calorimetry (DSC)

[0086] DSC samples for thermal analysis were prepared by weighing the material and loading it into an aluminum DSC sample tray from TA Instruments (New Castle, Delaware). The samples were analyzed using a TA Instruments Discovery Differential Scanning Calorimeter (DSC - SN DSC1-0091, New Castle, DE) in standard mode (10 °C / min from -155 °C to approximately 150 °C). After data collection, the thermal transitions were analyzed using TA's universal analytical procedures. The glass transition temperature was assessed using a step change in the standard heat flux (HF) curve. The midpoint (half-high) temperature of the second thermal transition was reported.

[0087] Examples 1 to 8 (E1-E8) and Comparative Examples 1 to 11 (C1-C11)

[0088] The thiol-ene / acetylene formulations were prepared from a mixture of liquid thiols and olefins / acetylenes, with mass ratios as shown in Table 2 below. The mass ratios were chosen such that the molar ratio of thiol groups to olefin groups was 1:1, and in formulations containing acetylene groups, two equivalents of thiol were used for each acetylene group. TPO-L was added at 3% by weight to the thiols and olefins or acetylenes listed in Table 2, and the formulations were thoroughly mixed. The liquid formulations were cast onto a polyethylene terephthalate (PET) substrate using a Mayer rod (No. 10) and cured using a UV LED curing system (Clearstone Technologies Inc., Hopkins, MN), 395 nm, 100% intensity corresponding to 319 mW / cm². 2 UV curing was performed at a distance of 1 cm from the sample surface for 2 minutes. A transparent hard coating was obtained. The refractive index and glass transition temperature of the sample were tested, and the results are reported in Table 2.

[0089] Comparative Example 12 (C12), namely the methacrylate resin derived from biphenyl methyl acrylate (M1) and bisphenol fluorene diacrylate (M2), was prepared according to Example 4 in U.S. Patent Publication No. 2019 / 0352520 (Schwartz et al.). The refractive index is reported in Table 2.

[0090]

[0091] As shown in the table above, generally, T3 increases the refractive index of the cured product compared to the comparison sample using the same thiol. TPATTC and the mixed TA / P TCU increase both the refractive index and Tg compared to the comparison sample using the same thiol.

[0092] Foreseeable modifications and alterations to the invention will be apparent to those skilled in the art without departing from its scope and spirit. The invention should not be limited to the embodiments shown in this application for illustrative purposes. In the event of any conflict or contradiction between the disclosure in this written specification and any document incorporated herein by reference, the written specification shall prevail.

Claims

1. A curable ink composition, said curable ink composition comprising: At least one unsaturated trithiocyanurate derivative according to formula (I) Where R 1 R 2 and R 3 Each independently includes terminal olefins or terminal alkynes; and At least one polyfunctional thiol, wherein the polyfunctional thiol is a non-aromatic thiol or an aromatic thiol having a refractive index of at least 1.620; The curable ink composition is substantially solvent-free.

2. The curable ink composition according to claim 1, wherein R 1 R 2 Or R 3 At least one of them is -CH2CH=CH2, -CH2CH2CH=CH2, -CH2CH2CH2CH=CH2, -CH2CCH3=CH2 or -CH2(phenyl)CH=CH2.

3. The curable ink composition according to any one of the preceding claims, wherein R 1 R 2 Or R 3 At least one of them is -CH2C≡CH, -CH2CH2C≡CH, -CH2CH2CH2C≡CH or -CH2(phenyl)C≡CH.

4. The curable ink composition according to any one of the preceding claims, wherein R 1 R 2 Or R 3 At least one of them includes terminal alkynes.

5. The curable ink composition according to any one of the preceding claims, wherein the ratio of thiol groups to the terminal olefin is 1:0.8 to 0.8:

1.

6. The curable ink composition according to any one of the preceding claims, wherein the ratio of thiol groups to the terminal alkynes is from 2:0.8 to 1.6:

1.

7. The curable ink composition according to any one of the preceding claims, wherein the trithiocyanurate derivative according to formula (I) is: , , , , Or a mixture thereof.

8. The curable ink composition according to any one of the preceding claims, wherein the polyfunctional thiol is an aromatic thiol.

9. The curable ink composition according to any one of the preceding claims, wherein the polyfunctional thiol is 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane; 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane; 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane; 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane or a mixture thereof.

10. The curable ink composition according to any one of the preceding claims, wherein, Apart from the unsaturated trithiocyanurate derivative according to formula (I), the curable ink composition is substantially free of another monomer containing at least two terminal unsaturated groups, wherein the terminal unsaturated groups are selected from C-C double bonds and C-C triple bonds.

11. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition further comprises a free radical initiator.

12. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition has a liquid refractive index of at least 1.

630.

13. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition further comprises an inhibitor.

14. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition further comprises a heat stabilizer.

15. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition further comprises an adhesion promoter.

16. The curable ink composition according to any one of the preceding claims, wherein the curable ink composition has a viscosity of 100 cp or less at a temperature from room temperature to 35°C.

17. An article comprising: A substrate having a first main surface and a second main surface; A cured organic layer, said cured organic layer being adjacent to at least a portion of the second main surface of said substrate, wherein said cured organic layer is derived from at least one unsaturated trithiocyanurate derivative according to formula (I). Where R 1 R 2 and R 3 Each can independently include terminal olefins or terminal alkynes; and at least one polyfunctional thiol; as well as An inorganic barrier layer is in contact with the cured organic layer, wherein the cured organic layer has a refractive index of at least 1.700 (measured at 450 nm).

18. The article of claim 17, wherein the cured organic layer is optically transparent.

19. The article of any one of claims 17 to 18, wherein the cured organic layer has a glass transition temperature of at least 10°C.

20. The article of any one of claims 17 to 19, wherein the cured organic layer has a thickness of 1 micrometer to 16 micrometers and a surface roughness of less than or equal to 5 nanometers.

21. The article of any one of claims 17 to 20, wherein the article of any one of claims 17 to 20 further comprises a device disposed on the second main surface of the substrate and adjacent to the cured organic layer.

22. The article of manufacture according to claim 21, wherein the device comprises an OLED (organic light-emitting diode).

23. A method for preparing an article, the method comprising: A substrate having a first main surface and a second main surface is provided; A curable ink composition is provided, the curable ink composition comprising at least one unsaturated trithiocyanurate derivative according to formula (I). Where R 1 R 2 and R 3 Each can independently include terminal olefins or terminal alkynes; and at least one polyfunctional thiol, The curable ink composition is disposed on at least a portion of the second main surface of the substrate to form a curable layer; The curable layer is cured to form a cured organic layer, wherein the cured organic layer has a refractive index of at least 1.70 measured at 450 nm; and An inorganic barrier layer is deposited on the cured organic layer.

24. The method of claim 23, wherein disposing of the curable ink composition on the second main surface of the substrate to form a curable layer comprises inkjet printing to a thickness of 1 micrometer to 16 micrometers.

25. The method according to any one of claims 23 to 24, the method further comprising providing a device; and The device is disposed on the second main surface of the substrate before the curable ink composition is disposed on the second main surface of the substrate to form a curable layer.

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