Fluorinated photoinitiators and fluorinated (co)polymer layers prepared using the same

Abstract

Fluorinated photoinitiators and polymerizable compositions comprising such fluorinated photoinitiators and at least one free-radically polymerizable monomer, oligomer or mixture thereof are described. Also described are multilayer films comprising a substrate and at least a first layer covering a surface of said substrate, wherein the at least first layer comprises a (co)polymer obtained by polymerization of the aforementioned polymerizable composition. Also taught is a method of making a multilayer film using the polymerizable composition. Also disclosed are articles comprising the multilayer film, wherein the article is preferably selected from a photovoltaic device, a display device, a solid state lighting device, a sensor, a medical or biological diagnostic device, an electrochromic device, a light control device or a combination thereof.

Description

Technical Field

[0001] This disclosure relates to fluorinated photoinitiators and methods for forming fluorinated (co)polymer layers in multilayer films, more specifically, multilayer optical films, using fluorinated photoinitiators. Background Technology

[0002] Crosslinked (co)polymer layers have been used in films for electrical, packaging, and decorative applications. These layers provide desired properties such as optical properties, mechanical strength, heat resistance, chemical resistance, abrasion resistance, transparency, refractive index, and clarity. Multilayer optical films incorporating crosslinked (co)polymer layers are also known.

[0003] Such multilayer films can be prepared using a variety of manufacturing methods. These methods include liquid coating techniques such as solution coating, roll coating, dip coating, spray coating, and spin coating; and dry coating techniques such as monomer evaporation and curing, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), initiated chemical vapor deposition (iCVD), plasma polymerization, and molecular layer deposition (MLD). One method for preparing multilayer optical films is to prepare inorganic optical layers, such as alumina, silicon oxide, titanium oxide, or silicon nitride, with dispersed (co)polymer optical layers. Inorganic layers can be deposited using various methods, including CVD, PECVD, atomic layer deposition (ALD), sputtering, and vacuum processes for thermal or electron beam evaporation of solid materials.

[0004] Examples of such multilayer films and methods for forming such films can be found, for example, in U.S. Patents 5,877,895 (Shaw et al.); 6,815,043 (Fleming et al.); 6,838,183 (Yializis); 6,929,864 (Fleming et al.); 7,215,473 (Fleming); and US20160306084 (Padiyath et al.). These multilayer films have numerous applications in the markets of displays, optics, lighting, chemical sensors, biosensors / diagnostics, and solar energy. Summary of the Invention

[0005] This disclosure describes the synthesis of fluorinated photoinitiators for the preparation of fluorinated (co)polymers suitable for multilayer film applications. These fluorinated photoinitiators typically (1) are soluble in and compatible with fluorinated monomers, oligomers, and polymers, (2) rapidly initiate free radical polymerization upon irradiation with photochemical radiation such as ultraviolet or visible light (UV-VIS), (3) rapidly chemically bond to free radical polymerizable fluorinated monomers, oligomers, and (co)polymers (e.g., hexafluoropropylene oxide (HFPO)-diacrylate monomers, oligomers, and (co)polymers), and (4) do not result in a significant increase in the low refractive index of the formed fluorinated (co)polymer layer. This combination of properties allows these fluorinated photoinitiators to be used to produce robust, chemically bonded fluorinated (co)polymer layers or films on surfaces where fluorinated materials are typically incompatible (e.g., inorganic layers such as silica).

[0006] Therefore, in one aspect, this disclosure describes fluorinated photoinitiators having the following formula:

[0007]

[0008] in:

[0009] X 31 X 32 X 33 X 34 X 35 Each can be independently selected from -H, -F, or -CF3, provided that X 31 X 32 X 33 X 34 X 35 At least three of them are -F or X 31 X 32 X 33 X 34 X 35 At least one of them is -CF3;

[0010] Y 31 Y 32 Y 33 Y 34 Y 35 Each is independently selected from -H or CH3; and

[0011] R 31 It is an alkyl group with 1 to 4 carbon atoms.

[0012] In another respect, this disclosure describes polymerizable compositions comprising the aforementioned fluorinated photoinitiator and at least one free radical polymerizable monomer, oligomer, or mixture thereof.

[0013] In another aspect, this disclosure describes a multilayer film comprising a substrate and at least a first layer covering the surface of the substrate, wherein the first layer comprises a (co)polymer obtained by polymerizing the aforementioned polymerizable composition.

[0014] In another aspect, this disclosure describes articles comprising a multilayer film according to the foregoing embodiments, wherein the articles are selected from photovoltaic devices, display devices, solid-state lighting devices, sensors, medical or biological diagnostic devices, electrochromic devices, light control devices, or combinations thereof.

[0015] In another aspect, this disclosure describes a method for preparing a multilayer film, the method comprising forming at least one (co)polymer layer covering a substrate, wherein the (co)polymer layer comprises a reaction product of the aforementioned polymerizable composition, and applying at least one adhesion-promoting layer to the covering substrate, optionally wherein the adhesion-promoting layer comprises an inorganic oxide, a nitride, a nitrogen oxide, a carbon oxide, a hydroxylated (co)polymer, or a combination thereof.

[0016] Exemplary embodiments of this disclosure provide multilayer films that exhibit improved moisture resistance when used in moisture-proof applications. Exemplary embodiments of this disclosure are capable of forming multilayer films that exhibit excellent mechanical properties such as elasticity and flexibility while still having low oxygen or water vapor transport rates. Exemplary embodiments of the multilayer films according to this disclosure are preferably transmissive to both visible and infrared light. Exemplary embodiments of the multilayer films according to this disclosure are generally also flexible. Exemplary embodiments of the multilayer films according to this disclosure generally do not exhibit delamination or curling in the multilayer structure that can be caused by thermal stress or shrinkage. The properties of the exemplary embodiments of the multilayer films disclosed herein are generally maintained even after high-temperature and humid aging.

[0017] Various aspects and advantages of the exemplary embodiments of this disclosure have been summarized. The above summary is not intended to describe every illustrative embodiment or every implementation of the presently available exemplary embodiments of this disclosure. The following drawings and detailed descriptions illustrate more specifically certain preferred embodiments using the principles disclosed herein.

[0018] This disclosure describes the synthesis of fluorinated photoinitiators for the preparation of fluorinated (co)polymers suitable for multilayer film applications. These fluorinated photoinitiators typically (1) are soluble in and compatible with fluorinated monomers, oligomers, and polymers, (2) rapidly initiate free radical polymerization upon irradiation with photochemical radiation such as ultraviolet or visible light (UV-VIS), (3) rapidly chemically bond to free radical polymerizable fluorinated monomers, oligomers, and (co)polymers (e.g., hexafluoropropylene oxide (HFPO)-diacrylate monomers, oligomers, and (co)polymers), and (4) do not result in a significant increase in the low refractive index of the formed fluorinated (co)polymer layer. This combination of properties allows these fluorinated photoinitiators to be used to produce robust, chemically bonded fluorinated (co)polymer layers or films on surfaces where fluorinated materials are typically incompatible (e.g., inorganic layers such as silica).

[0019] Therefore, in one aspect, this disclosure describes fluorinated photoinitiators having the following formula:

[0020]

[0021] in:

[0022] X 31 X 32 X 33 X 34 X 35 Each can be independently selected from -H, -F, or -CF3, provided that X 31 X 32 X 33 X 34 X 35 At least three of them are -F or X 31 X 32 X 33 X 34 X 35 At least one of them is -CF3;

[0023] Y 31 Y 32 Y 33 Y 34 Y 35 Each is independently selected from -H or CH3; and

[0024] R 31 It is an alkyl group with 1 to 4 carbon atoms.

[0025] In another respect, this disclosure describes polymerizable compositions comprising the aforementioned fluorinated photoinitiator and at least one free radical polymerizable monomer, oligomer, or mixture thereof.

[0026] In another aspect, this disclosure describes a multilayer film comprising a substrate and at least a first layer covering a surface of the substrate, wherein the first layer comprises a (co)polymer obtained by polymerizing the aforementioned polymerizable composition.

[0027] In another aspect, this disclosure describes articles comprising a multilayer film according to the foregoing embodiments, wherein the articles are selected from photovoltaic devices, display devices, solid-state lighting devices, sensors, medical or biological diagnostic devices, electrochromic devices, light control devices, or combinations thereof.

[0028] In another aspect, this disclosure describes a method for preparing a multilayer film, the method comprising forming at least one (co)polymer layer covering a substrate, wherein the (co)polymer layer comprises a reaction product of the aforementioned polymerizable composition, and applying at least one adhesion-promoting layer to the covering substrate, optionally wherein the adhesion-promoting layer comprises an inorganic oxide, a nitride, a nitrogen oxide, a carbon oxide, a hydroxylated (co)polymer, or a combination thereof.

[0029] Exemplary embodiments of this disclosure provide multilayer films that exhibit improved moisture resistance when used in moisture-proof applications. Exemplary embodiments of this disclosure are capable of forming multilayer films that exhibit excellent mechanical properties such as elasticity and flexibility while still having low oxygen or water vapor transport rates. Exemplary embodiments of the multilayer films according to this disclosure are preferably transmissive to both visible and infrared light. Exemplary embodiments of the multilayer films according to this disclosure are generally also flexible. Exemplary embodiments of the multilayer films according to this disclosure generally do not exhibit delamination or curling in the multilayer structure that can be caused by thermal stress or shrinkage. The properties of the exemplary embodiments of the multilayer films disclosed herein are generally maintained even after high-temperature and humid aging.

[0030] Various aspects and advantages of the exemplary embodiments of this disclosure have been summarized. The above summary is not intended to describe every illustrative embodiment or every implementation of the presently available exemplary embodiments of this disclosure. The following drawings and detailed descriptions illustrate more specifically certain preferred embodiments using the principles disclosed herein. Attached Figure Description

[0031] The accompanying drawings, together with the detailed embodiments, are incorporated in and constitute a part of this specification, illustrating the advantages and principles of exemplary embodiments of the present invention.

[0032] Figure 1 This is a diagram illustrating an exemplary multilayer film according to an exemplary embodiment of the present disclosure, the multilayer film being incorporated with a (co)polymer layer formed using a fluorinated photoinitiator;

[0033] Figure 2This is a diagram illustrating an exemplary process for preparing a multilayer film according to an exemplary embodiment of the present disclosure, the multilayer film comprising at least one layer formed using a fluorinated photoinitiator.

[0034] Figure 3 The UV-VIS spectrum of an exemplary fluorinated photoinitiator according to an embodiment of this disclosure;

[0035] Figure 4 The UV-VIS spectrum of an exemplary fluorinated photoinitiator according to another embodiment of this disclosure; and

[0036] Figure 5 This is an exemplary UV-VIS spectrum of a fluorinated photoinitiator according to yet another embodiment of this disclosure.

[0037] The same reference numerals in the accompanying drawings indicate the same elements. The drawings herein are not drawn to scale, and the dimensions of the elements shown are set to emphasize selected features. Detailed Implementation

[0038] Glossary

[0039] While most terms used throughout the specification and claims are well-known, some interpretation may still be necessary. It should be understood that, as used herein,

[0040] When describing the position of a layer relative to the substrate or other layers of the multilayer film of this disclosure using the terms “covering,” “stack,” and “covering,” we refer to a layer as being on top of the substrate or other layers, but not necessarily adjacent to or continuing the substrate or layers.

[0041] By using the term "separated by," we describe the position of a layer relative to one or more other layers, referring to the other layers as being between the layer and the substrate or another different layer, but not necessarily adjacent to or continuing with the substrate or another different layer.

[0042] The terms “(co)polymer” and “polymer” include homopolymers and copolymers, such as homopolymers or copolymers that can be formed, for example, by co-extrusion or by reaction (including, for example, transesterification) in the form of miscible blends. The term “copolymer” includes both random polymers and block copolymers.

[0043] The term "coupling agent" refers to a compound that provides a chemical bond between two different materials, typically inorganic and organic. Coupling agents are usually multifunctional molecules or oligomers that can be used to achieve crosslinking during chemical reactions, such as free radical polymerization, to form (co)polymers.

[0044] The term "membrane" or "layer" refers to a single layer within a multilayer membrane.

[0045] The terms “(meth)acryloyl” or “(meth)acrylate” for monomers, oligomers, (co)polymers, or compounds refer to vinyl-functionalized alkyl esters formed as products of the reaction of alcohols with acrylic acid or methacrylic acid.

[0046] The term "crosslinked" (co)polymer refers to a (co)polymer whose (co)polymer chains are joined together by covalent chemical bonds, typically via crosslinked molecules or groups, to form a network (co)polymer. Crosslinked (co)polymers are typically characterized by their insolubility but can be swollen in the presence of a suitable solvent.

[0047] The term "curing" refers to a process that causes a chemical change, such as a reaction that creates covalent bonds to harden a layer or increase its viscosity.

[0048] The term "cured (co)polymer" includes both cross-linked and uncross-linked polymers.

[0049] The term "low refractive index" refers to a material or layer with a refractive index of 1.3 to 1.5.

[0050] The term "high refractive index" refers to a material or layer with a refractive index of 1.5 to 2.5.

[0051] The term "metal" includes pure metals or metal alloys.

[0052] The term "photoinitiator" refers to such materials, and more specifically, such molecules, whose

[0053] When exposed to photochemical radiation (e.g., ultraviolet (UV), visible (VIS), or infrared (IR) light), reactive substances (e.g., free radicals, cations, or anions) are produced.

[0054] The terms "vapor phase coating" or "vapor phase deposition" refer to the application of a coating to a substrate surface by means of, for example, evaporation and subsequent deposition of a precursor material or the coating material itself onto the substrate surface. Exemplary vapor phase coating processes include, for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), and combinations thereof.

[0055] By using the term "visible-transmissive" in relation to a carrier, layer, component, article, or device, we mean that the carrier, layer, component, or device has an average transmittance T of at least about 20% measured along the normal axis in the visible portion of the spectrum. vis .

[0056] Various exemplary embodiments of the present disclosure will now be described with specific reference to the accompanying drawings. Various modifications and alterations may be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, it should be understood that the embodiments of the present disclosure are not limited to the exemplary embodiments described below, but are subject to the limiting factors shown in the claims and any equivalents.

[0057] For electronic and / or optical devices requiring flexibility and durability, flexible layers in multilayer films are essential. Flexible multilayer films offer advantages over glass because they are flexible, lightweight, durable, and enable low-cost continuous roll-to-roll processing.

[0058] Although various photoinitiators are known and commercially available, it is desirable and advantageous to provide a fluorinated photoinitiator that can readily react with other fluorinated monomers or oligomers to form fluorinated (co)polymers without adversely affecting the interlayer adhesion of the fluorinated (co)polymer layers in the multilayer film.

[0059] Fluorinated photoinitiators

[0060] In exemplary embodiments, this disclosure describes fluorinated photoinitiators having the following formula:

[0061]

[0062] in:

[0063] X 31 X 32 X 33 X 34 X 35 Each can be independently selected from -H, -F, or -CF3, provided that X 31 X 32 X 33 X 34 X 35 At least three of them are -F or X 31 X 32 X 33 X 34 X 35 At least one of them is -CF3;

[0064] Y 31 Y 32 Y 33 Y 34 Y 35 Each is independently selected from -H or CH3; and

[0065] R 31 It is an alkyl group with 1 to 4 carbon atoms.

[0066] In some exemplary embodiments, the fluorinated photoinitiator has a calculated number-average molecular weight of not more than 700 g / mol, 600 g / mol, 500 g / mol, or 400 g / mol. In some exemplary embodiments, the fluorinated photoinitiator has a fluorine content of at least 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, or 50 wt%.

[0067] polymerizable compositions

[0068] In another exemplary embodiment, this disclosure describes a polymerizable composition comprising at least one of the aforementioned fluorinated photoinitiators and at least one radical-polymerizable monomer, oligomer, or mixture thereof.

[0069] In some exemplary embodiments, the polymerizable composition comprises at least 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, or 4.0 wt% of a fluorinated photoinitiator, based on the weight of the polymerizable composition. In some such exemplary embodiments, the polymerizable composition comprises no more than about 10.0 wt%, 7.5 wt%, 5.0 wt%, 4.0 wt%, or 3.0 wt% of a fluorinated photoinitiator, based on the weight of the polymerizable composition.

[0070] In some of the foregoing embodiments, the radical-polymerizable monomers, oligomers, or combinations thereof are fluorinated. Preferably, the radical-polymerizable monomers, oligomers, or combinations thereof have a fluorine content of at least 25 wt%, 30 wt%, or 35 wt%. In some of the foregoing embodiments, the polymerizable composition comprises a fluorinated oligomer containing a perfluorooxyalkylene or perfluorooxyalkyl group.

[0071] In some of the foregoing embodiments, the polymerizable composition comprises at least one of a (meth)acrylic monomer or oligomer, optionally including at least one of the (meth)acrylic monomers or oligomers as described below, the HFPO oligomer diacrylate.

[0072] Multilayer film including at least one fluorinated (co)polymer layer

[0073] Turn to the attached diagram. Figure 1This is a diagram of a multilayer film 10 having a moisture-proof coating comprising a single paired layer. Film 10 includes layers arranged in the following order: a substrate 12; an adhesion-promoting layer 14; at least one fluorinated (co)polymer layer 16; an optional adhesion-promoting layer 18; and an optional fluorinated (co)polymer layer 20. The adhesion-promoting layer 14 and the fluorinated (co)polymer layer 16 together form a paired layer. Some embodiments include one paired layer, other embodiments include two paired layers as shown, and film 10 may include additional paired layers of alternating adhesion-promoting layer 18 and fluorinated (co)polymer layer 20 between the substrate 10 and the uppermost paired layer.

[0074] The polymerizable composition may be co-deposited or sequentially deposited to form a fluorinated (co)polymer layer 16. In some exemplary embodiments, the fluorinated (co)polymer layer 16 improves the moisture resistance of the membrane 10 and the peel strength and / or adhesion of the fluorinated (co)polymer layer 18 to adjacent adhesion-promoting layers, thereby producing improved interlayer adhesion and favorable anti-delamination properties within the multilayer membrane, as further explained below. Currently preferred materials for the multilayer membrane 10 are further identified below and in the examples.

[0075] Therefore, in another exemplary embodiment, this disclosure describes at least one multilayer film comprising a substrate and at least a first layer covering the surface of the substrate, the first layer comprising a (co)polymer obtained by polymerizing at least one of the aforementioned polymerizable compositions comprising at least one of the aforementioned fluorinated photoinitiators.

[0076] In another exemplary embodiment, the multilayer film further includes at least one additional layer adjacent to the first layer. In some exemplary embodiments, the multilayer film further includes a plurality of alternating layers comprising: an adhesion-promoting layer covering the substrate and comprising inorganic oxides, nitrides, nitrogen oxides, carbon oxides; metals or metal alloys; (co)polymers, or combinations thereof; and an adjacent (co)polymer layer covering the substrate and comprising (co)polymers.

[0077] In some exemplary embodiments, the multilayer article includes an adhesion-promoting layer and a plurality of alternating layers of fluorinated (co)polymer layers on at least one fluorinated (co)polymer layer. The adhesion-promoting layer and the fluorinated (co)polymer layers together form "paired layers," and in one exemplary embodiment, the multilayer film may include more than one pair of layers to form a multilayer film. Each of the adhesion-promoting layer and / or fluorinated (co)polymer layers in the multilayer film (i.e., including more than one pair of layers) may be the same or different. An optional inorganic layer, preferably an adhesion-promoting layer, may be applied over the plurality of alternating layers or paired layers.

[0078] base

[0079] The substrate 12 may be a flexible visible light transmitting substrate, such as a flexible light transmitting polymer film. In a currently preferred exemplary embodiment, the substrate is substantially transparent and may have a visible light transmittance of at least about 50%, 60%, 70%, 80%, 90%, or even up to about 100% at 550 nm.

[0080] Exemplary flexible light-transmitting substrates include thermoplastic polymer films, including, for example, polyesters, poly(meth)acrylates (e.g., polymethyl methacrylate), polycarbonate, polypropylene, high- or low-density polyethylene, polysulfone, polyethersulfone, polyurethane, polyamide, polyvinyl butyral, polyvinyl chloride, fluoropolymers (e.g., polyvinylidene fluoride, ethylene-tetrafluoroethylene (ETFE) (co)polymer, tetrafluoroethylene (co)polymer, hexafluoropropylene (co)polymer, polytetrafluoroethylene and copolymers thereof), polyethylene sulfide, cycloolefin (co)polymers, and thermosetting films such as epoxy resins, cellulose derivatives, polyimides, polyimide-benzoxazole, and polybenzoxazole.

[0081] Therefore, in some exemplary embodiments, the substrate includes a flexible transparent (co)polymer film selected from or comprising polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate (PETg), polyethylene naphthalate (PEN), heat-stable PET, heat-stable PEN, polyoxymethylene, polyvinyl naphthalene, polyetheretherketone, fluoropolymers, polycarbonate, polymethyl methacrylate, polyalphamethylstyrene, polysulfone, polyphenylene ether, polyetherimide, polyethersulfone, polyamideimide, polyimide, polyphthalamide, cyclic olefin polymer (COP), cyclic olefin copolymer (COC), cellulose triacetate (TAC), or combinations thereof.

[0082] Currently preferred (co)polymer base films include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), heat-stable PET, heat-stable PEN, polyoxymethylene, polyvinyl naphthalene, polyether ether ketone, fluoropolymers, polycarbonate, polymethyl methacrylate, polyalphamethylstyrene, polysulfone, polyphenylene ether, polyetherimide, polyethersulfone, polyamide imide, polyimide, polyphthalamide, or combinations thereof.

[0083] In some currently preferred exemplary embodiments, the substrate may be a multilayer optical film (“MOF”), such as those described in U.S. Patent Application Publication US 2004 / 0032658 A1. In one currently preferred exemplary embodiment, the substrate is a PET substrate.

[0084] The substrate can have various thicknesses, for example, from about 0.01 mm to about 1 mm. However, the substrate can be quite thick, for example, when a self-supporting article is required. Such articles can also be conveniently fabricated by laminating, or in other words, bonding the disclosed film made using a flexible substrate to a thicker, non-flexible or less flexible supplementary carrier.

[0085] The substrate can be advantageously selected as a thermally stable (co)polymer film, for example, in cases where heat setting, tension annealing, or other techniques that prevent or limit shrinkage up to at least the thermally stable temperature when the (co)polymer film is unconstrained are used.

[0086] Fluorinated (co)polymer layer

[0087] Back Figure 1 At least one fluorinated (co)polymer layer 16 may contain any fluorinated (co)polymer, but must contain at least one of the following fluorinated (co)polymers derived from any of the aforementioned polymerizable compositions containing at least one fluorinated photoinitiator.

[0088] For example, at least one fluorinated (co)polymer layer 16 can be formed by applying a layer of any of the aforementioned polymerizable compositions to a substrate and curing or crosslinking the layer to form the fluorinated (co)polymer in situ, for example by flash evaporation and vapor deposition of a radiation-crosslinkable monomer, followed by crosslinking using, for example, an electron beam apparatus, a UV light source, a discharge apparatus, or other suitable means. Coating efficiency can be improved by cooling the substrate.

[0089] The polymerizable composition can also be applied to the substrate 12 using conventional coating methods such as roll coating (e.g., gravure roll coating) or spray coating (e.g., electrostatic spraying), and then crosslinked as described above. At least one fluorinated (co)polymer layer 16 can also be formed by applying a layer containing a polymerizable composition dissolved or dispersed in a solvent or other liquid medium and drying the applied layer to remove the solvent.

[0090] Chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), initiated chemical vapor deposition (iCVD), plasma polymerization, and molecular layer deposition (MLD) can also be used to apply polymerizable compositions to form a layer covering a substrate and to cure or crosslink the layer, as further described below.

[0091] Preferably, at least one fluorinated (co)polymer layer 16 is formed by flash evaporation and vapor deposition, followed by in-situ crosslinking, as described, for example, in the following documents: U.S. Patents 4,696,719 (Bischoff), 4,722,515 (Ham), 4,842,893 (Yializis et al.), 4,954,371 (Yializis), 5,018,048 (Shaw et al.), 5,032,461 (Shaw et al.), 5,097,800 (Shaw et al.), 5,125,138 (Shaw et al.), 5,440,446 (Shaw et al.), 5,547,908 (Furuzawa et al.), 6,045,864 (Lyons et al.), 6,231,939 (Shaw et al.), and 6,214,422 (Yializis); PCT International Publication WO 00 / 26973 (Delta V Technologies, Inc.); DG Shaw and M. Glanglois, “A New Vapor Deposition Process for Coating Paper and Polymer Webs,” 6th International Vacuum Coating Conference (1992); DG Shaw and M. Glanglois, “A New High Speed ​​Process for Vapor Depositing Acrylate Thin Films: An Update,” Society of Vacuum Coaters 36th Annual Technical Conference Proceedings (1993); DG Shaw and M. GlangloisLanglois, “Use of Vapor Deposited Acrylate Coatings to Improve the Barrier Properties of Metallized Film”, Society of Vacuum Coaters 37th Annual Technical Conference Proceedings (1994); DG Shaw, M. Roehrig, M. Langlois and C. Sheehan, “Use of Evaporated Acrylate Coatings to Smooth the Surface of Polyester and Polypropylene Film” Substrates, RadTech (1996) (D.G. Shaw, M. Roehrig, M. G. Langlois, and C. Sheehan, “Using Evaporated Acrylic Coatings to Smooth the Surface of Polyester and Polypropylene Film Substrates”, RadTech (1996)); J. Affinito, P. Martin, M. Gross, C. Coronado, and E. Greenwell, “Vacuum Deposited Polymer / Metal Multilayer Films for Optical Applications”, Thin Solid Films 270, 43-48 (1995); and J. Affinito, M. Gross, C. Coronado, G. Graff, E. Greenwell, and P. Martin, “Polymer-Oxide Transparent Layers”, Society of Vacuum Coatings 39th Annual Technical Meeting (1996) (D.G. Shaw, M. Roehrig, M. G. Langlois, and C. Sheehan, “Using Evaporated Acrylic Coatings to Smooth the Surface of Polyester and Polypropylene Film Substrates”, RadTech (1996)); J. Affinito, P. Martin, M. Gross, C. Coronado, and E. Greenwell, “Vacuum Deposited Polymer / Metal Multilayer Films for Optical Applications”, Thin Solid Films 270, 43-48 (1995)); and J. Affinito, M. Gross, C. Coronado, G. Graff, E. Greenwell, and P. Martin, “Polymer-Oxide Transparent Layers”, Society of Vacuum Coatings 39th Annual Technical Meeting (1996) (D.G. Shaw, M. Roehrig, M. G. Langlois, and C. Sheehan, “Using Evaporated Acrylic Coatings to Smooth the Surface of Polyester and Polypropylene Film Substrates”, Solid Solid Films 2 Coaters 39th Annual Technical Conference Proceedings(1996)). .

[0092] In some exemplary embodiments, the smoothness and continuity of at least one fluorinated (co)polymer layer 16 (and optionally each adhesion-promoting layer 14 and fluorinated (co)polymer layer 20) and its adhesion to the underlying substrate or layer can be enhanced by appropriate pretreatment. Examples of suitable pretreatment methods include discharge in the presence of a suitable reactive or non-reactive atmosphere (e.g., plasma, glow discharge, corona discharge, dielectric barrier discharge, or atmospheric pressure discharge); chemical pretreatment; or flame pretreatment. These pretreatments help to make the surface of the underlying layer more receptive to the formation of the subsequently applied polymeric (or inorganic) layer. Plasma pretreatment may be particularly available.

[0093] In some exemplary embodiments, a separate adhesion-promoting layer, which may have a different composition from at least one fluorinated (co)polymer layer 16, may also be used on top of the substrate or the underlying layer to improve adhesion. The adhesion-promoting layer may be, for example, a single polymer layer or a metal-containing layer, such as a metal layer, a metal oxide layer, a metal nitride layer, or a metal oxynitride layer. The adhesion-promoting layer may have a thickness of several nanometers (e.g., 1 nm or 2 nm) to approximately 50 nm, and may be thicker if desired.

[0094] The desired chemical composition and thickness of at least one fluorinated (co)polymer layer will depend in part on the properties and surface morphology of the substrate and the adhesion-promoting layer. This thickness is preferably sufficient to provide a smooth, defect-free surface on which a subsequent adhesion-promoting layer can be applied. For example, at least one fluorinated (co)polymer layer can have a thickness of several nanometers (e.g., 2 nm or 3 nm) to approximately 5 micrometers, and can be thicker if desired.

[0095] Oligomers that can be polymerized by free radicals

[0096] Back Figure 1In one aspect, for example, at least one fluorinated (co)polymer layer 16 may be formed from various precursors, such as fluorinated and / or non-fluorinated (meth)acrylate monomers and / or oligomers, including isobornyl (meth)acrylate, pentaerythritol penta(meth)acrylate, epoxy (meth)acrylate, epoxy (meth)acrylate blended with styrene, di-trimethylolpropane tetra(meth)acrylate, diethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, penta(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, ethyl... Oxylated (3)trimethylolpropane tri(meth)acrylate, ethoxylated (3)trimethylolpropane tri(meth)acrylate, alkoxylated trifunctional (meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated (4)bisphenol A dimethyl (meth)acrylate, tricyclodecanediethanol di(meth)acrylate, cyclohexanediethanol di(meth)acrylate, isobornyl methacrylate, cyclic di(meth)acrylate and tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and carbamate (meth)acrylate. Such compounds are widely available from suppliers such as Sartomer Company, Exton, Pennsylvania; UCB Chemicals Corporation (Smyrna, Georgia); and Aldrich Chemical Company, Milwaukee, Wisconsin, or can be prepared by standard methods. Other available (meth)acrylate materials include poly(meth)acrylates containing a dihydroxyhydantoin moiety, such as those described in U.S. Patent No. 4,262,072 (Wendling et al.). Preferably, at least one fluorinated (co)polymer layer precursor comprises a fluorinated or non-fluorinated (meth)acrylate monomer.

[0097] Fluorinated monomers

[0098] In some embodiments, the (meth)acrylate monomers and / or oligomers comprise highly fluorinated monomers. Perfluorooxyalkyl and perfluorooxyalkylene compounds can be obtained by oligomerizing hexafluoropropylene oxide, which results in the formation of a terminal carbonyl fluoride group. This carbonyl fluoride can be converted to an ester by reactions known to those skilled in the art. The preparation of perfluorinated methyl ester compounds is described, for example, in US 3,250,808 and US 9,718,896. The preparation of perfluorooxyalkyl and perfluorooxyalkylene compounds containing a (meth)acryloyl group is also known. See, for example, US 9,718,896. Examples include di(meth)acrylates comprising a hexafluoropropylene oxide oligomer (HFPO) moiety. In some such exemplary embodiments, the radically polymerizable monomers, oligomers, or combinations thereof have a fluorine content of at least 25 wt%, 30 wt%, or 35 wt%. In some of the foregoing embodiments, the polymerizable composition comprises at least one of a (meth)acrylic acid monomer or oligomer, optionally wherein at least one of the (meth)acrylic acid monomers or oligomers comprises an HFPO oligomer diacrylate having the following structure: CH2=CHC(O)O-H2C-(CF3)CF-[OCF2(CF3)CF] s -O(CF2) u O-[CF(CF3)CF2O] t -CF(CF3)-CH2-OC(O)CH=CH2, having a number-average molecular weight of, for example, about 2000 g / mol, is prepared according to the synthetic method generally described in US 9,718,961 (PFE-3). Here, HFPO refers to the perfluoroalkylene group "-HFPO-", which is -(CF3)CF-[OCF2(CF3)CF] s -O(CF2) u O-[CF(CF3)CF2O] t -CF(CF3)-, where u is 2 to 6, and s and t are independently integers from 2 to 25. In some embodiments, p is 3 or 4. In some embodiments, the sum of s and t is at least 3, 4, 5, 6, 7, 8, 9, or 10. In some embodiments, the sum of s and t is not greater than 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10. Divalent -HFPO- is also commonly found as a distribution or mixture of molecules with a range of s and t values. Therefore, s and t can be expressed as averages. Such averages are usually not integers.

[0099] Adhesion promoting layer

[0100] Multilayer films may include deposited adhesion-promoting layers that cover or, in some embodiments, are directly deposited on a substrate that optionally includes electronic or optical devices; this process is often referred to as direct encapsulation. The electronic or optical devices may be, for example, organic, inorganic, or hybrid organic / inorganic semiconductor devices, including, for example, photovoltaic devices such as copper indium gallium diselenide (CIGS) photovoltaic devices; display devices such as organic light-emitting diodes (OLEDs), electrochromic or electrophoretic displays; OLEDs or other electroluminescent solid-state lighting devices, or others.

[0101] Flexible electronic devices can be directly encapsulated using a gradient composition adhesion-promoting layer. For example, the device can be attached to a flexible carrier substrate, and a mask can be deposited to protect electrical connections from the deposition of the adhesion-promoting layer. At least one fluorinated (co)polymer layer 16, adhesion-promoting layer 14, and optional adhesion-promoting layer 18, as well as optional fluorinated (co)polymer layer 20, can be deposited as further described below, and then the mask can be removed to expose the electrical connections.

[0102] In some exemplary embodiments, the adhesion promoting layer comprises at least one of the following: oxides, nitrides, carbides, borides, or combinations thereof of atomic elements selected from Groups IIA, IIIA, IVA, IVB, VA, VB, VIA, VIIA, IB, or IIB; metals or combinations thereof selected from Groups IIIA, IIIB, IVA, IVB, VB, VIB, or VIIIB; rare earth metals or combinations thereof; or (meth)acrylic acid (co)polymers or combinations thereof.

[0103] In some currently preferred embodiments, the oxide, nitride, carbide, or boride comprises aluminum, indium, silicon, tin, titanium, zirconium, hafnium, vanadium, niobium, tantalum, cerium, strontium, or combinations thereof; and the metal or metal alloy comprises aluminum, silicon, germanium, copper, silver, gold, titanium, zirconium, chromium, nickel, or combinations thereof.

[0104] In some specific exemplary embodiments, an inorganic layer, more preferably an inorganic adhesion-promoting layer, may be applied to the topmost fluorinated (co)polymer layer. Preferably, the adhesion-promoting layer comprises silicon aluminum oxide or indium tin oxide.

[0105] In some exemplary embodiments, the composition of the adhesion-promoting layer can vary along the thickness direction of the layer, i.e., a gradient composition. In such exemplary embodiments, the adhesion-promoting layer preferably comprises at least two inorganic materials, and the ratio of the two inorganic materials varies throughout the thickness of the adhesion-promoting layer. The ratio of the two inorganic materials refers to the relative proportion of each of the inorganic materials. This ratio can be, for example, a mass ratio, volume ratio, concentration ratio, molar ratio, surface area ratio, or atomic ratio.

[0106] The resulting gradient adhesion-promoting layer shows improvement compared to a uniform single-component layer. When combined with vacuum-deposited fluorinated (co)polymer thin layers, additional beneficial effects on blocking and optical properties can be achieved. Multilayer gradient inorganic (co)polymer blocking laminates can be prepared to improve both optical and blocking properties.

[0107] As further described below, multilayer films can be fabricated by depositing individual layers onto a substrate in a roll-to-roll vacuum chamber similar to the systems described in U.S. Patents 5,440,446 (Shaw et al.) and 7,018,713 (Padiyath et al.). Layer deposition can be in-line and occur in a single pass through the system. In some cases, the multilayer film can pass through the system several times to form a multilayer film with several pairs of layers.

[0108] The first and second inorganic materials can be oxides, nitrides, carbides, or borides of metallic or nonmetallic atomic elements, or combinations of metallic or nonmetallic atomic elements. "Metallic or nonmetallic" atomic elements refer to atomic elements selected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, IB, or IIB of the periodic table, metals from Groups IIIB, IVB, or VB, rare earth metals, or combinations thereof. Suitable inorganic materials include, for example, metal oxides, metal nitrides, metal carbides, metal nitrides, metal boron oxides, and combinations thereof, such as silicon oxide (e.g., silicon dioxide), aluminum oxide (e.g., bauxite), titanium oxide (e.g., titanium dioxide), indium oxide, tin oxide, indium tin oxide ("ITO"), tantalum oxide, zirconium oxide, niobium oxide, aluminum nitride, silicon nitride, boron nitride, aluminum oxynitride, silicon oxynitride, boron oxynitride, zirconium boron oxide, titanium boron oxide, and combinations thereof. ITO is an example of a specific class of ceramic materials that can become conductive by correctly selecting the relative proportions of the elemental components. Silicon-aluminum oxide and indium tin oxide are currently preferred inorganic materials for forming the adhesion-promoting layer 14.

[0109] For clarity, the adhesion-promoting layer 14 described in the following discussion relates to an oxide composition; however, it should be understood that the composition may contain any of the oxides, nitrides, carbides, borides, oxynitrides, borosilicates, etc., described above.

[0110] In one exemplary embodiment of such an adhesion-promoting layer 14, the first inorganic material is silicon oxide and the second inorganic material is aluminum oxide. In this embodiment, the atomic ratio of silicon to aluminum varies throughout the thickness of the adhesion-promoting layer; for example, there is more silicon than aluminum near the first surface of the adhesion-promoting layer, gradually becoming more aluminum than silicon with increasing distance from the first surface. In one embodiment, the atomic ratio of silicon to aluminum may change monotonically with increasing distance from the first surface; that is, the ratio increases or decreases with increasing distance from the first surface, but the ratio does not both increase and decrease with increasing distance from the first surface. In another embodiment, the ratio does not increase or decrease monotonically; that is, the ratio may increase in a first portion and decrease in a second portion with increasing distance from the first surface. In this embodiment, there may be several increases and decreases in the ratio with increasing distance from the first surface, and the ratio is non-monotonic. Variations in the concentration of inorganic oxides from one oxide material to another throughout the thickness of the adhesion-promoting layer 14 result in improved barrier properties, as measured by water vapor transport rates.

[0111] In addition to improved barrier properties, gradient compositions can be formulated to exhibit other unique optical properties while maintaining these improved barrier properties. The gradient variation in the composition of the layers produces a corresponding variation in the refractive index that transmits through the layers. Materials can be selected such that the refractive index varies from high to low, and vice versa. For example, a high to low refractive index allows light propagating in one direction to easily penetrate the layer, while light propagating in the opposite direction can be reflected by the layer.

[0112] Refractive index variations can be used to design layers that enhance light extraction from the protected light-emitting device. Additionally, refractive index variations can be used to allow light to pass through the layer and into light-harvesting devices (e.g., solar cells). Other optical structures (e.g., bandpass filters) can also be incorporated into the layer while maintaining improved barrier properties.

[0113] To promote silane bonding to the oxide surface, it is desirable to form hydroxysilanol (Si-OH) groups on the newly sputtered silica (SiO2) layer. The amount of water vapor present in the multi-process vacuum chamber can be sufficiently controlled to promote the formation of Si-OH groups at a sufficiently high surface concentration, thereby providing increased bonding sites. With monitoring of residual gases and the use of a water vapor source, the amount of water vapor in the vacuum chamber can be controlled to ensure sufficient Si-OH group formation.

[0114] Articles including multilayer films having fluorinated (co)polymer layers

[0115] In another aspect, this disclosure describes articles comprising a multilayer film according to any of the foregoing embodiments, wherein the articles are selected from photovoltaic devices, display devices, solid-state lighting devices, sensors, medical or biological diagnostic devices, electrochromic devices, light control devices, or combinations thereof.

[0116] Methods for preparing multilayer films

[0117] In other exemplary embodiments, this disclosure describes various methods for preparing multilayer films comprising at least one of the aforementioned fluorinated (co)polymer layers, which are formed by a reaction (e.g., free radical polymerization) of at least one of the aforementioned polymerizable compositions comprising at least one of the aforementioned fluorinated photoinitiators, and are applied to a substrate. The methods include forming a (co)polymer layer covering the main surface of any of the aforementioned substrates.

[0118] Therefore, in exemplary embodiments, this disclosure describes a method for preparing a multilayer film, the method comprising forming at least one (co)polymer layer covering a substrate, wherein the (co)polymer layer is a reaction product of any of the aforementioned polymerizable compositions comprising one of the aforementioned fluorinated photoinitiators, and applying at least one adhesion-promoting layer to the covering substrate. In some such embodiments, the adhesion-promoting layer comprises inorganic oxides, nitrides, oxynitrides, carbon oxides, hydroxylated (co)polymers, or combinations thereof.

[0119] In some exemplary embodiments, forming the (co)polymer layer further includes evaporating the polymerizable composition, condensing the evaporated polymerizable composition or (co)polymer into a layer covering the substrate, and reacting the polymerizable composition in the layer to form the (co)polymer. In some such embodiments, the polymerizable composition comprises at least 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, or 4.0 wt% of a fluorinated photoinitiator, based on the weight of the polymerizable composition.

[0120] In some of the foregoing embodiments, applying the adhesion-promoting layer includes depositing at least one of a metal oxide, a metal oxide precursor, a metal nitride, a metal nitride precursor, a metal oxynitride, a metal oxynitride precursor, a carbon oxide, a carbon oxide precursor, a hydroxylated (co)polymer, or a hydroxylated (co)polymer precursor onto a substrate. In some such exemplary embodiments, deposition is achieved using sputtering deposition, reactive sputtering, thermal evaporation, electron beam evaporation, chemical vapor deposition, plasma-assisted chemical vapor deposition, atomic layer deposition, plasma-assisted atomic layer deposition, or combinations thereof.

[0121] In another exemplary embodiment, the method further includes successively repeating the forming and applying steps to produce a plurality of paired layers, each paired layer comprising an adhesion-promoting layer covering the substrate and comprising an inorganic oxide, nitride, oxynitride, carbon oxide, (co)polymer, or a combination thereof, and an adjacent (co)polymer layer covering the substrate and comprising the (co)polymer.

[0122] In some such exemplary embodiments, the evaporable polymerizable composition further includes at least one of the following: co-evaporating a fluorinated photoinitiator and at least one radical-polymerizable monomer, oligomer, or mixture thereof from a liquid mixture, or sequentially evaporating a fluorinated photoinitiator and at least one radical-polymerizable monomer, oligomer, or mixture thereof from a separate liquid source.

[0123] In some such exemplary embodiments, the polymerizable composition contains an amount of fluorinated photoinitiator not exceeding about 10.0 wt%, 7.5 wt%, 5.0 wt%, 4.0 wt%, or 3.0 wt%, based on the weight of the polymerizable composition.

[0124] In another exemplary embodiment of this kind, the polymerizable composition further comprises at least one of the following: co-condensing a fluorinated photoinitiator with at least one radically polymerizable monomer, oligomer, or mixture thereof into a layer covering the substrate, or successively condensing the fluorinated photoinitiator and the at least one radically polymerizable monomer, oligomer, or mixture thereof into a layer covering the substrate.

[0125] In some such exemplary embodiments, the reaction of the fluorinated photoinitiator with at least one radically polymerizable monomer, oligomer, or mixture thereof occurs at least partially in a layer covering the substrate, optionally wherein the reaction of the fluorinated photoinitiator with at least one radically polymerizable monomer, oligomer, or mixture thereof includes crosslinking initiated by applying heat, photochemical radiation, electron beam radiation, gamma radiation, plasma, or a combination thereof.

[0126] In some currently preferred embodiments of this type, the adhesion-promoting layer comprises at least one of the following: oxides, nitrides, carbides, borides, or combinations thereof of atomic elements selected from Groups IIA, IIIA, IVA, IVB, VA, VB, VIA, VIIA, IB, or IIB; metals or combinations thereof selected from Groups IIIA, IIIB, IVA, IVB, VB, VIB, or VIIIB; rare earth metals or combinations thereof; or (meth)acrylate (co)polymers or combinations thereof, optionally wherein the oxides, nitrides, carbides, or borides comprise aluminum, indium, silicon, tin, titanium, zirconium, hafnium, vanadium, niobium, tantalum, cerium, strontium, or combinations thereof; and the metal or metal alloy comprises aluminum, silicon, germanium, copper, silver, gold, titanium, zirconium, chromium, nickel, or combinations thereof.

[0127] Fluorinated (copolymer) layers are formed using a vapor phase coating process.

[0128] Vapor deposition or coating processes can be advantageously used to produce flexible and durable multilayer films that can be used in flexible electronics and / or optical devices.

[0129] Chemical vapor deposition (CVD and PECVD) forms vaporized metal or metal oxide precursors, which react chemically when adsorbed onto a substrate to form an inorganic coating. Vacuum vapor deposition processes, such as thermal evaporation of solid materials (e.g., resistance heating or electron beam heating), can also be used. Sputtering has also been used to form metal adhesion-promoting layers.

[0130] Please refer to the attached diagram again. Figure 2 This is a diagram of system 22, which illustrates an exemplary vapor-phase coating process for preparing the multilayer film 10. System 22 is housed in an inert environment and includes a refrigerated rotary drum 24 for receiving and moving the substrate 12. Figure 1 ), as represented by membrane 26, thereby providing a movable roll on which layers are formed. Preferably, membrane 26 may be plasma-treated or primed using an optional plasma treatment unit 40 to improve adhesion promoting layer 14 ( Figure 1 ) and base 12 ( Figure 1 The oxide sputtering unit 32 applies oxide to form layer 14 as the rotating drum 24 advances the film 26. Figure 1 Evaporator 36 applies at least one fluorinated (co)polymer layer precursor, which is cured by curing unit 38 to form at least one fluorinated (co)polymer layer 16 as the film 26 is advanced by the rotating drum 24 in the direction indicated by arrow 25. Figure 1 ).

[0131] For the additional alternating adhesion-promoting layer 18 and fluorinated (co)polymer layer 20, the drum 24 may rotate in the opposite direction to arrow 25, and then advance the membrane 26 again to apply the additional alternating adhesion-promoting layer and at least one fluorinated (co)polymer layer, and this subprocess may be repeated for as many alternating layers as desired or required. In some currently preferred embodiments, reacting a (meth)acryloyl compound with a (meth)acryloyl-silane compound to form a fluorinated (co)polymer layer 16 on the adhesion-promoting layer 14 occurs at least partially on the adhesion-promoting layer 14.

[0132] An optional evaporator 34 can also be used to provide a fluorinated (co)polymer layer 16 ( Figure 1Other co-reactants or comonomers (e.g., additional (meth)acryloyl compounds). For additional alternating adhesion-promoting layers 14 and fluorinated (co)polymer layers 16, the drum 24 may rotate in the opposite direction to arrow 25 and then advance the film 26 again to apply additional alternating adhesion-promoting layers 14 and fluorinated (co)polymer layers 16, and this subprocess may be repeated for as many alternating or paired layers as desired or required.

[0133] The adhesion-promoting layer 14 can be formed using techniques employed in the field of film metallization, such as sputtering (e.g., cathode or planar magnetron sputtering), evaporation (e.g., resistive or electron beam evaporation), chemical vapor deposition, plasma-enhanced chemical vapor deposition, atomic layer deposition, monomer evaporation and curing, initiated chemical vapor deposition, plasma polymerization, molecular layer deposition, electroplating, etc. In one aspect, the adhesion-promoting layer 14 is formed using sputtering, such as reactive sputtering. Enhanced barrier properties have been observed when the adhesion-promoting layer is formed using high-energy deposition techniques such as sputtering, which are relative to lower-energy techniques such as conventional chemical vapor deposition processes. Without being bound by theory, it is believed that, as occurs in sputtering, the enhanced properties are due to the greater kinetic energy of the condensed material reaching the substrate, resulting in a lower porosity due to compaction.

[0134] In some exemplary embodiments, the sputtering deposition process can utilize a dual-target system powered by an alternating current (AC) power source in the presence of an inert and reactive gas atmosphere (e.g., argon and oxygen, respectively). The AC power source alternately changes the polarity of each of the dual targets, such that for half of an AC cycle, one target is the cathode and the other the anode. In the next cycle, the polarity is switched between the dual targets. This switching occurs at a set frequency (e.g., about 40 kHz), but other frequencies may also be used. Oxygen introduced into the process forms an adhesion-promoting layer on both the substrate receiving the inorganic composition and the surface of the targets. Dielectric oxides can become charged during sputtering, thereby disrupting the sputtering deposition process. The polarity switching neutralizes the surface material sputtered from the targets and provides uniformity and better control of the deposited material.

[0135] In another exemplary embodiment, each of the targets used for dual AC sputtering may contain a single metallic or non-metallic element, or a mixture of metallic and / or non-metallic elements. The first portion of the adhesion-promoting layer closest to the moving substrate is deposited using a first set of sputtering targets. The substrate is then moved closer to a second set of sputtering targets, and a second portion of the adhesion-promoting layer is deposited on top of the first portion using the second set of sputtering targets. The composition of the adhesion-promoting layer varies along the thickness direction of the entire layer.

[0136] In another exemplary embodiment, in the presence of a gas atmosphere containing inert and reactive gases (e.g., argon and oxygen, respectively), the sputtering deposition process can utilize a target powered by a direct current (DC) power supply. The DC power source supplies power to each cathode target independently of other power sources (e.g., pulsed power). In this respect, each individual cathode target and its corresponding material can be sputtered at different power levels, thereby providing additional control over the composition throughout the layer thickness. The pulsed aspect of the DC power source is analogous to the frequency aspect in AC sputtering, thus allowing control over high-rate sputtering in the presence of reactive gas species such as oxygen. The pulsed DC power source allows for control of polarity reversal, neutralizing surface material sputtered from the target, and can provide uniformity and better control over the deposited material.

[0137] In one particular exemplary embodiment, improved control during sputtering can be achieved by using a mixture or atomic composition of elements in each target, for example, the target may contain a mixture of aluminum and silicon. In another embodiment, the relative proportions of the elements in each target may differ to easily provide varying atomic ratios throughout the adhesion-promoting layer. In one embodiment, for example, a first set of dual-AC sputtering targets may contain a 90 / 10 mixture of silicon and aluminum, and a second set of dual-AC sputtering targets may contain a 75 / 25 mixture of aluminum and silicon. In this embodiment, a first portion of the adhesion-promoting layer may be deposited using a 90% Si / 10% Al target, and a second portion may be deposited using a 75% Al / 25% Si target. The resulting adhesion-promoting layer has a gradient composition that varies from about 90% Si to about 25% Si (and conversely from about 10% Al to about 75% Al) across the entire thickness of the adhesion-promoting layer.

[0138] In typical dual-AC sputtering, a uniform adhesion-promoting layer is formed, but the barrier properties of this uniform adhesion-promoting layer are impaired due to micron and nanoscale defects in the layer. One cause of these small-scale defects is intrinsically due to the growth of oxides into grain boundary structures, which then propagate throughout the film thickness. Without being bound by theory, several effects are believed to contribute to improving the barrier properties of the gradient composition barrier described herein. One effect could be to densify the mixed oxides present in the gradient region, thereby blocking any path that water vapor might take through the oxides. Another effect could be that by changing the composition of the oxide material, grain boundary formation can be disrupted, resulting in variations in the film microstructure across the thickness of the adhesion-promoting layer. Yet another effect could be that the concentration of one oxide gradually decreases as the concentration of the other oxide increases throughout the thickness, thereby reducing the probability of forming small-scale defect sites. The reduction of defect sites can lead to a coating with reduced water permeability.

[0139] Before depositing the fluorinated monomers from evaporator 38 onto the fluorinated coupling agent layer, the fluorinated coupling agent is immediately applied as an additional adhesion-promoting layer using optional evaporator 34. Figure 1 (Not shown) Deposited on adhesion-promoting layer 14 ( Figure 1 As the film is advanced by roller / drum 24, the two layers (fluorinated coupling agent and fluorinated monomer) are cured together by curing unit 38 to form fluorinated (co)polymer layer 16. Deposition of (meth)acryloyl-silane and (meth)acryloyl compound may involve the sequential evaporation of (meth)acryloyl compound and (meth)acryloyl-silane compound from separate sources, or the co-evaporation of a mixture of (meth)acryloyl compound and (meth)acryloyl-silane compound. The adhesion-promoting layer can be post-treated, for example, by heat treatment, ultraviolet (UV) or vacuum UV (VUV) treatment, or plasma treatment. Heat treatment can be performed by passing the film through an oven or by directly heating the film in the coating apparatus, for example, using an infrared heater or directly on the drum. For example, heat treatment can be performed at temperatures from about 30°C to about 200°C, from about 35°C to about 150°C, or from about 40°C to about 70°C.

[0140] Other functional layers or coatings that may be added to the inorganic or hybrid membrane include one or more optional layers that make the membrane more rigid. The uppermost layer of the membrane is optionally a suitable protective layer, such as an optional inorganic layer 20. If desired, the protective layer can be applied using conventional coating methods such as roll coating (e.g., gravure roll coating) or spray coating (e.g., electrostatic spraying), followed by crosslinking using, for example, UV radiation. The protective layer can also be formed by flash evaporation, vapor deposition, and crosslinking of the monomers described above. Volatile (meth)acrylate monomers are suitable for use in such protective layers. In a specific embodiment, volatile (meth)acrylate monomers are employed.

[0141] Using multilayer film method

[0142] On the other hand, this disclosure describes a method of using a multilayer film prepared as described above in an article of manufacture, wherein the article of manufacture is selected from photovoltaic devices, display devices, solid-state lighting devices, sensors, medical or biological diagnostic devices, electrochromic devices, light-controlled devices, and combinations thereof. Currently preferred articles of manufacture incorporating such multilayer films include flexible thin films (e.g., copper indium gallium diselenide, CIGS) and organic photovoltaic solar cells, as well as organic light-emitting diodes (OLEDs) used in displays and solid-state lighting. Currently, these applications are generally limited to non-flexible glass substrates used as vapor barriers.

[0143] Exemplary embodiments of this disclosure provide multilayer films that exhibit improved moisture resistance when used in moisture-proof applications. In some exemplary embodiments, the multilayer film can be deposited directly on a substrate including electronic or optical devices, a process commonly referred to as direct encapsulation. The electronic or optical devices can be, for example, organic, inorganic, or hybrid organic / inorganic semiconductor devices, including, for example, photovoltaic devices such as CIGS; display devices such as OLEDs, electrochromic displays, or electrophoretic displays; OLEDs or other electroluminescent solid-state lighting devices, or others. Flexible electronic devices can be directly encapsulated using a gradient composition adhesion-promoting layer. For example, the device can be attached to a flexible carrier substrate, and a mask can be deposited to protect electrical connections from the deposition of the adhesion-promoting layer. At least one fluorinated (co)polymer layer and adhesion-promoting layer can be deposited as described above, and then the mask can be removed to expose the electrical connections.

[0144] Exemplary embodiments of the methods disclosed herein can allow the formation of multilayer membranes exhibiting superior mechanical properties such as elasticity and flexibility while still having low oxygen or water vapor transport rates. The membrane has at least one inorganic or hybrid organic / adhesion-promoting layer, or may have additional inorganic or hybrid organic / adhesion-promoting layers. In one embodiment, the disclosed membrane may have inorganic or hybrid layers alternating with organic compounds (e.g., (co)polymer layers). In another embodiment, the membrane may be a membrane comprising inorganic or hybrid materials and organic compounds.

[0145] Exemplary embodiments of the multilayer films according to this disclosure are preferably transmissive to photochemical radiation (e.g., ultraviolet, visible, and / or infrared light). As used herein, the term "transmissive to visible and infrared light" can refer to an average transmittance of at least about 75% (in some embodiments at least about 80%, 85%, 90%, 92%, 95%, 97%, or 98%) for the visible and infrared portions of the spectrum, measured along the normal axis. In some embodiments, the transmissive components have an average transmittance of at least about 75% (in some embodiments at least about 80%, 85%, 90%, 92%, 95%, 97%, or 98%) in the 400 nm to 1400 nm range. Transmissive components are those that do not interfere with the absorption of visible and infrared light by, for example, photovoltaic cells.

[0146] In some exemplary embodiments, the component capable of transmitting visible and infrared light has an average transmittance of at least about 75% (in some embodiments at least about 80%, 85%, 90%, 92%, 95%, 97%, or 98%) in the wavelength range of light useful to the photovoltaic cell. The first and second polymer film substrates, pressure-sensitive adhesive layers, and multilayer films can be selected based on refractive index and thickness to enhance the transmittance of visible and infrared light. Suitable methods for selecting refractive index and / or thickness to improve the transmittance of visible and / or infrared light are described in co-pending PCT International Publications WO 2012 / 003416 and WO 2012 / 003417.

[0147] The exemplary multilayer films according to this disclosure are generally flexible. As used herein, the term "flexible" means capable of being formed into a roll. In some embodiments, the term "flexible" means capable of being bent around a core with a radius of curvature of up to 7.6 cm (3 inches), and in some embodiments up to 6.4 cm (2.5 inches), 5 cm (2 inches), 3.8 cm (1.5 inches), or 2.5 cm (1 inch). In some embodiments, the flexible component can be bent around a radius of curvature of at least 0.635 cm (1 / 4 inch), 1.3 cm (1 / 2 inch), or 1.9 cm (3 / 4 inch).

[0148] The exemplary multilayer films according to this disclosure generally do not exhibit delamination or curling that can be caused by thermal stress or shrinkage in the multilayer structure. In this document, curling is measured using a curling degree measuring instrument described by Ronald P. Swanson in “Measurement of Web Curl” presented in the 2006 AWEB Conference Proceedings (Association of Industrial Metallizers, Coaters and Laminators, Applied Web Handling Conference Proceedings 2006). According to this method, curling can be measured at 0.25m... -1 Curvature resolution is measured for curl. In some embodiments, the multilayer film according to this disclosure exhibits a maximum curvature of up to 7m. -1 6m -1 5m -1 4m -1 or 3m -1The curling of the sample. According to solid mechanics, the curvature of a beam is known to be proportional to the bending moment applied to it. The magnitude of the bending stress is also known to be proportional to the bending moment. Based on these relationships, the curling of the sample can be used to compare residual stress. Barrier films typically also exhibit high peel adhesion to EVA and other commonly used photovoltaic encapsulants cured on the substrate. Generally, the properties of the multilayer films disclosed herein are maintained even after aging at high temperatures and humidity.

[0149] The operation of this disclosure will be further described with reference to the embodiments detailed below. These embodiments are provided to further illustrate various specific and preferred implementations and techniques. However, it should be understood that many variations and modifications can be made while still falling within the scope of this disclosure.

[0150] Example

[0151] Unless otherwise specified, all parts, percentages, and ratios in the examples are by weight. Unless otherwise specified, all solvents and other reagents used were obtained from Sigma-Aldrich Chemical Company (Milwaukee, WI).

[0152] Material

[0153] Table 1 lists the materials used to prepare the fluorinated photoinitiators according to the foregoing disclosure:

[0154] Table 1 :

[0155] Materials used in the embodiments

[0156]

[0157] Synthesis process :

[0158] Example 1: Pentafluorobenzoylmethoxyphenylphosphine oxide

[0159]

[0160] Pentafluorobenzoylmethoxyphenylphosphine oxide was synthesized in a flame-dried, three-necked round-bottom flask equipped with a thermocouple, magnetic stir bar, and liquid feeding funnel, under yellow ambient light and vacuum. The round-bottom flask was refilled with dry nitrogen, and 9.92 g (58.3 mmol) of dimethoxyphenylphosphine was added.

[0161] 13.44 g (58.3 mmol) of pentafluorobenzoyl chloride was added to a liquid feeding funnel, and the reaction apparatus was connected to a vacuum. The round-bottom flask was cooled with a dry ice / isopropanol bath, and pentafluorobenzoyl chloride was added dropwise at a rate sufficient to keep the reaction temperature below 15 °C. During this process, the reaction mixture turned into a bright yellow-orange pourable viscous oil. The quantitative yield of pentafluorobenzoylmethoxyphenylphosphine oxide was collected and stored in a brown glass bottle. The reaction product was confirmed by ¹H NMR.

[0162] Example 2: Bis-trifluoromethylbenzoylmethoxyphenylphosphine oxide

[0163]

[0164] Bis-trifluoromethylbenzoylmethoxyphenylphosphine oxide was synthesized under yellow ambient light and vacuum in a flame-dried, three-necked round-bottom flask equipped with a thermocouple, magnetic stir bar, and liquid feeding funnel. The round-bottom flask was refilled with dry nitrogen, and 9.54 g (56.1 mmol) of dimethoxyphenylphosphine was added. 15.51 g (56.1 mmol) of bis-trifluoromethylbenzoyl chloride was added to the liquid feeding funnel, and the reaction apparatus was connected to a vacuum. The round-bottom flask was cooled with dry ice / water bath, and trifluoromethylbenzoyl chloride was added dropwise at a rate sufficient to keep the reaction temperature below 15 °C. During this process, the reaction mixture turned into a pale yellow and very viscous oil, which inhibited continuous magnetic stirring during the reaction. The quantitative yield of bis-trifluoromethylbenzoylmethoxyphenylphosphine oxide was collected and stored in a brown glass bottle. ¹H NMR confirmed the reaction product.

[0165] Ultraviolet-Visible (UV-VIS) Spectrum

[0166] UV-VIS spectra of the fluorinated photoinitiators of Examples 1 and 2 were collected using a PerkinElmer LAMBDA 365UV / Vis spectrophotometer at concentrations of 0.1 and 0.01 w / w in acetonitrile, respectively, relative to an acetonitrile reference. These photoinitiators exhibit strong UV absorption characteristics, and their absorption spectra tail into the visible (violet-blue) region of the spectrum, particularly at higher concentrations, such as... Figures 3 to 5 As shown.

[0167] Throughout this specification, the terms "an embodiment," "certain embodiments," "one or more embodiments," or "implementation," whether or not preceded by the term "exemplary," mean that a particular feature, structure, material, or characteristic described in connection with that embodiment is included in at least one of the exemplary embodiments of this disclosure. Therefore, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment of the exemplary embodiments of this disclosure. Furthermore, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0168] While certain exemplary embodiments have been described in detail in this specification, it should be understood that modifications, variations, and equivalents of these embodiments will readily occur to those skilled in the art upon understanding the foregoing. Therefore, it should be understood that this disclosure should not be unduly limited to the exemplary embodiments shown above. In particular, as used herein, numerical ranges expressed in terms of endpoints are intended to include all values ​​contained within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Furthermore, all numbers used herein are considered to be modified by the term “about”.

[0169] Furthermore, all publications and patents cited herein are incorporated herein by reference in their entirety, as if each individual publication or patent were specifically and individually indicated to be incorporated by reference. Various exemplary embodiments have been described. These and other embodiments are within the scope of the following claims.

Claims

1. A fluorinated photoinitiator, said fluorinated photoinitiator having the following formula: in: X 31 X 32 X 33 X 34 X 35 Each can be independently selected from -H, -F, or -CF3, provided that X 31 X 32 X 33 X 34 X 35 At least three of them are -F or X 31 X 32 X 33 X 34 X 35 At least one of them is -CF3; Y 31 Y 32 Y 33 Y 34 Y 35 Each is independently selected from -H or CH3; and R 31 It is an alkyl group with 1 to 4 carbon atoms.

2. A polymerizable composition, said polymerizable composition comprising: The fluorinated photoinitiator according to claim 1; and At least one monomer, oligomer, or mixture thereof that can be polymerized by free radicals.

3. The polymerizable composition according to claim 2, wherein the free radical polymerizable monomer, oligomer, or combination thereof is fluorinated.

4. The polymerizable composition according to claim 2, wherein the free radical polymerizable monomer, oligomer, or combination thereof has a fluorine content of at least 25% by weight.

5. The polymerizable composition according to claim 2, wherein the polymerizable composition comprises a fluorinated oligomer containing a perfluorooxyalkylene group.

6. The polymerizable composition of claim 2, wherein, based on the weight of the polymerizable composition, the polymerizable composition comprises an amount of the fluorinated photoinitiator not exceeding 10.0% by weight.

7. The polymerizable composition according to claim 2, wherein the fluorinated photoinitiator has a calculated number-average molecular weight of not more than 700 g / mol.

8. The polymerizable composition according to claim 2, wherein the fluorinated photoinitiator has a fluorine content of at least 10% by weight.

9. The polymerizable composition according to any one of claims 2 to 8, wherein the polymerizable composition further comprises a (meth)acrylic acid oligomer, wherein the (meth)acrylic acid oligomer comprises an HFPO oligomer diacrylate having the structure: CH2=CHC(O)O-H2C-(CF3)CF-[OCF2(CF3)CF] s -O(CF2) u O-[CF(CF3)CF2O] t -CF(CF3)-CH2-OC(O)CH=CH2, where u is 2 to 6, and s and t are independent integers from 2 to 25.

10. A multilayer film, said multilayer film comprising: Base; At least a first layer covering the surface of the substrate, wherein the first layer comprises a polymer obtained by polymerizing the polymerizable composition according to claim 2.

11. The multilayer film of claim 10, wherein the free radical polymerizable monomer, oligomer, or combination thereof is fluorinated.

12. The multilayer film of claim 10, wherein the free radical polymerizable monomer, oligomer, or combination thereof has a fluorine content of at least 25% by weight.

13. The multilayer film of claim 10, wherein the composition comprises a fluorinated oligomer containing a perfluorooxyalkylene group.

14. The multilayer film of claim 10, wherein, based on the weight of the polymerizable composition, the polymerizable composition comprises at least 0.1% by weight of the fluorinated photoinitiator.

15. The multilayer film of claim 14, wherein, based on the weight of the polymerizable composition, the polymerizable composition comprises an amount of the fluorinated photoinitiator not exceeding 10.0% by weight.

16. The multilayer film according to claim 10, wherein the fluorinated photoinitiator has a calculated number-average molecular weight of not more than 700 g / mol.

17. The multilayer film according to claim 10, wherein the fluorinated photoinitiator has a fluorine content of at least 10% by weight.

18. The multilayer film of claim 10, wherein the multilayer film further comprises at least one additional layer adjacent to the first layer.

19. The multilayer film according to claim 10, further comprising a plurality of alternating layers, the plurality of alternating layers comprising: An adhesion promoting layer, the adhesion promoting layer covering the substrate and comprising inorganic oxides, nitrides, nitrogen oxides, carbon oxides; metals or metal alloys; Polymers, or combinations thereof; and An adjacent polymer layer that covers the substrate and contains a polymer.

20. The multilayer film of claim 10, wherein the substrate comprises a flexible transparent polymer film, wherein the substrate comprises polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate, polyethylene naphthalate (PEN), polyoxymethylene, polyvinyl naphthalene, polyetheretherketone, fluoropolymer, polycarbonate, poly(meth)acrylate, poly(α-methylstyrene), polysulfone, polyphenylene ether, polyetherimide, polyethersulfone, polyamide-imide, polyimide, polyphthalamide, cycloolefin polymer (COP), cellulose triacetate (TAC), or combinations thereof.

21. The multilayer film of claim 19, wherein the adhesion promoting layer comprises at least one of the following: oxides, nitrides, carbides, borides, or combinations thereof of an element selected from Groups IIA, IIIA, IVA, IVB, VA, VB, VIA, VIIA, IB, or IIB; metals selected from Groups IIIA, IIIB, IVA, IVB, VB, VIB, or VIIIB; or (meth)acrylic polymers or combinations thereof.

22. An article of manufacture incorporating a multilayer film according to any one of claims 10 to 21, wherein the article of manufacture is selected from photovoltaic devices, display devices, solid-state lighting devices, sensors, medical or biological diagnostic devices, electrochromic devices, light control devices, or combinations thereof.

23. A method for preparing a multilayer film, the method comprising: Form at least one polymer layer covering the main surface of the substrate. The polymer layer is a reaction product of the polymerizable composition according to claim 2, optionally wherein, based on the weight of the polymerizable composition, the polymerizable composition contains at least 0.1% by weight of the fluorinated photoinitiator; and At least one adhesion-promoting layer is applied, the adhesion-promoting layer covering the main surface of the substrate.

24. The method of claim 23, wherein forming the at least one polymer layer further comprises: Evaporate the polymerizable composition; The evaporated polymerizable composition is condensed into a layer covering the substrate; as well as The polymerizable composition in the layer is reacted to form the polymer.

25. The method of claim 23, wherein applying the at least one adhesion-promoting layer comprises depositing at least one of a metal oxide, a metal oxide precursor, a metal, a metal precursor, a (meth)acrylic acid polymer, a (meth)acrylic acid polymer precursor, or a combination thereof onto the substrate to form the adhesion-promoting layer, wherein the deposition is performed using sputtering deposition, reactive sputtering, thermal evaporation, electron beam evaporation, atomic layer deposition, organic vapor deposition, or a combination thereof.

26. The method of claim 23, further comprising successively repeating the forming and applying steps to produce a plurality of paired layers, each paired layer comprising: An adhesion promoting layer, the adhesion promoting layer covering the substrate and comprising inorganic oxides, nitrides, nitrogen oxides, carbon oxides; metals or metal alloys; Polymers, or combinations thereof; and An adjacent polymer layer that covers the substrate and contains a polymer.

27. The method of claim 24, wherein evaporating the polymerizable composition further comprises at least one of: co-evaporating the fluorinated photoinitiator and the at least one radically polymerizable monomer, oligomer, or mixture thereof from a liquid mixture, or sequentially evaporating the fluorinated photoinitiator and the at least one radically polymerizable monomer, oligomer, or mixture thereof from a separate liquid source, optionally wherein the polymerizable composition contains an amount of the fluorinated photoinitiator not exceeding 10.0% by weight based on the weight of the polymerizable composition.

28. The method of claim 24, wherein condensing the polymerizable composition further comprises at least one of: co-condensing the fluorinated photoinitiator with the at least one radically polymerizable monomer, oligomer, or mixture thereof into a layer covering the substrate, or successively condensing the fluorinated photoinitiator and the at least one radically polymerizable monomer, oligomer, or mixture thereof into a layer covering the substrate.

29. The method of claim 23, wherein the reaction of the fluorinated photoinitiator with the at least one radically polymerizable monomer, oligomer, or mixture thereof occurs at least partially in the layer covering the substrate, wherein the reaction of the fluorinated photoinitiator with the at least one radically polymerizable monomer, oligomer, or mixture thereof comprises crosslinking by applying heat, photochemical radiation, electron beam radiation, gamma radiation, plasma radiation, or a combination thereof.

30. The method according to any one of claims 23 to 29, wherein the adhesion promoting layer comprises at least one of: oxides, nitrides, carbides, borides, or combinations thereof of an element selected from Groups IIA, IIIA, IVA, IVB, VA, VB, VIA, VIIA, IB, or IIB; metals selected from Groups IIIA, IIIB, IVA, IVB, VB, VIB, or VIIIB; or (meth)acrylic polymers or combinations thereof.

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