Retroreflective articles, kits, and methods including a retroreflective layer and an antireflective layer

Abstract

This disclosure provides a retroreflective article. The retroreflective article includes a retroreflective layer comprising a plurality of surface structural elements that collectively form a structured surface opposite a main surface; and an antireflective layer having a first main surface and an opposite second main surface. The second main surface of the antireflective layer is attached to the structured surface of the retroreflective layer. This disclosure also provides a method for retaining light in a greenhouse or building. The method includes attaching a retroreflective article to at least one of a transparent roof, wall, skylight, or window of the greenhouse or building, wherein the retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the greenhouse or building.

Description

Technical Field

[0001] This disclosure broadly relates to retroreflective articles. Specifically, this disclosure relates to retroreflective articles comprising a retroreflective layer and an antireflective layer. This disclosure also relates to a method and kit for retaining light in a greenhouse. Background Technology

[0002] Greenhouses and similar structures are widely in demand because they help meet the growing need for plants and allow for the cultivation of a wide variety of plants. Greenhouses also provide an option for utilizing land not directly suitable for agriculture. The average yield of plants, vegetables, fruits, and herbs is increasing year by year, necessitating the construction of efficient greenhouses. Greenhouses primarily protect plants from damaging weather and provide stable lighting and temperatures suitable for plant growth. Greenhouses are crucial for increasing the quantity and quality of cultivated plants / crops. Therefore, greenhouses are assembled in a way that controls solar radiation, thus providing plants with stable and desirable light and heat.

[0003] Solar radiation management in greenhouses is typically regulated through the use of additional technologies, including shading curtains, supplemental lighting, heating devices, and cooling systems. Consequently, optical materials and architectural design have been extensively explored to manage, control, and regulate light within greenhouses. Furthermore, artificial light escapes from the building's windows and skylights, resulting in a need for more artificial lighting than is actually required. Summary of the Invention

[0004] Retroreflective materials are characterized by their ability to redirect incident light back to its original source. These materials are commonly used in a variety of products, such as road signs, barriers, license plates, pavement markings and road marking tapes, as well as reflective strips for vehicles and clothing. Beyond these general uses, retroreflectors are also useful in greenhouse construction. As a layered component, retroreflectors are under exploratory research into the design and arrangement of materials to achieve efficient lighting in greenhouses. These retroreflectors include angular or hemispherical elements of various shapes, including protruding glass beads that provide retroreflection. Retroreflectors are generally designed to reflect internal artificial light to minimize light escape from the greenhouse or building. However, there is a need to provide effective lighting within greenhouses by transmitting solar radiation and retaining artificial light using retroreflective properties.

[0005] In a first aspect, this disclosure provides a retroreflective article. The retroreflective article includes an retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface opposite to a main surface; and an antireflective layer having a first main surface and an opposite second main surface. The second main surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

[0006] In a second aspect, this disclosure provides a method for retaining light (e.g., in a greenhouse). The method includes attaching a retroreflective article (according to the first aspect) to at least one of a transparent roof, wall, or window of the greenhouse, or to at least one of a window or skylight of a building. The retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the greenhouse or building.

[0007] In a third aspect, this disclosure provides a kit. The kit includes an antireflective layer comprising a plurality of surface structure elements that collectively form a structured surface opposite to a main surface; and an antireflective layer having a first main surface and an opposite second main surface.

[0008] The above overview of this disclosure is not intended to describe every disclosed embodiment or every implementation of this disclosure. The following description illustrates exemplary embodiments in more detail. Guidance is provided at several points throughout this application by way of a list of embodiments that can be used in various combinations. In each case, the referenced list is used only as a representative group and should not be construed as an exclusive list. Attached Figure Description

[0009] Figure 1 A schematic cross-sectional view of an exemplary embodiment of a retroreflective article according to the present disclosure is depicted.

[0010] Figure 2 A schematic cross-sectional view is depicted of another exemplary embodiment of a retroreflective article including an adhesive layer according to the present disclosure.

[0011] Figure 3 A schematic cross-sectional view is depicted of another exemplary embodiment of a retroreflective article including a barrier layer according to the present disclosure.

[0012] Figure 4 A schematic cross-sectional view of another exemplary embodiment of a retroreflective article according to the present disclosure is depicted, wherein the antireflective layer has an optically transparent adhesive.

[0013] Figure 5 A schematic cross-sectional view of another exemplary embodiment of a retroreflective article according to the present disclosure is depicted, wherein the antireflective layer has a skipped tooth pattern.

[0014] Figure 6 A schematic cross-sectional view of another exemplary embodiment of the retroreflective article according to the present disclosure is depicted, wherein the antireflective layer has a skipped tooth pattern and two adhesive layers are attached to the substrate.

[0015] Figure 7A schematic cross-sectional view of an exemplary embodiment of the kit in use is depicted, wherein the retroreflective layer is adhered to one side of the substrate by an adhesive layer, and the antireflective layer is adhered to the opposite side of the substrate by an optically clear adhesive.

[0016] While the foregoing figures illustrate several embodiments of this disclosure, other embodiments are contemplated as mentioned in the description. The figures are not necessarily drawn to scale. In all instances, this disclosure is provided by way of example rather than limitation. It should be understood that those skilled in the art can devise numerous other modifications and embodiments that fall within the scope of this invention and are consistent with the spirit of its principles. Detailed Implementation

[0017] Those skilled in the art will understand that variations and modifications may exist in this disclosure in addition to those specifically described. It should be understood that this disclosure includes all such variations and modifications. This disclosure also includes all such steps, features, compositions, and compounds individually or collectively mentioned or indicated in this specification, as well as any and all combinations of any or more of such steps or features.

[0018] For convenience, certain terms used in the specification and examples are listed herein before further description of this disclosure. These definitions should be read in conjunction with the remainder of this disclosure and should be understood by those skilled in the art. The terms used herein have meanings recognized and known to those skilled in the art, but for convenience and completeness, specific terms and their meanings are listed below.

[0019] As used herein, the term "at least one" is used to mean one or more, and therefore includes both single components and mixtures / combinations.

[0020] Terms such as “a,” “an,” and “the / described” are not intended to refer to a single entity, but rather to encompass general categories, which may be illustrated with specific examples. The terms “a,” “an,” and “the described” are used interchangeably with the term “at least one (kind).” The phrases “at least one of…” and “containing at least one of…” followed by a list refer to any item in the list, as well as any combination of two or more items in the list.

[0021] As used herein, the term “or” is generally used in its usual sense, including “and / or”, unless the context clearly indicates otherwise. The term “and / or” means one or all of the listed elements, or any combination of two or more of the listed elements.

[0022] As used herein, the terms “comprising” and “containing” are used in an inclusive, open-ended sense, meaning that they may include additional elements. It should not be construed as “consisting only of…”. Throughout this specification, unless the context otherwise requires, the word “comprising” and its variations (such as “containing” and “containing”) will be understood to imply inclusion of the stated elements or steps or groups of elements or steps, but not to exclude any other elements or steps.

[0023] The term "including" is used to mean "including but not limited to", and "including" and "including but not limited to" are used interchangeably.

[0024] Furthermore, throughout this document, all numerical values ​​are assumed to be modified by the term "approximately," and preferably by the term "precisely." As used herein, with respect to the quantity being measured, the term "approximately" refers to a deviation in the quantity being measured that is commensurate with the accuracy of the object being measured and the measuring equipment used, as a technician who would have expected such a degree of care in performing the measurement. Additionally, throughout this document, numerical ranges expressed by endpoints include all numbers contained within that range as well as endpoint values ​​(e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0025] As used herein, as a modifier of a characteristic or attribute, unless otherwise specifically defined, the term "approximately" means that the characteristic or attribute will be easily identifiable by a person skilled in the art without requiring absolute precision or a perfect match (e.g., within + / -20% for quantifiable characteristics). Unless otherwise specifically defined, the term "substantially" means a high degree of approximation (e.g., within + / -10% for quantifiable characteristics), but again, absolute precision or a perfect match is not required. Terms such as identical, equal, uniform, constant, and rigorous should be understood as being within the generally permissible error or measurement error applicable to the specific situation, rather than requiring absolute precision or a perfect match.

[0026] The terms "preferred" and "ideally" refer to embodiments of this disclosure that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this disclosure.

[0027] The term "barrier layer" refers to a layer designed to be opaque or resistant to ultraviolet radiation and / or atomic oxygen.

[0028] The term "(co)polymer" includes homopolymers and (co)polymers, as well as homopolymers or (co)polymers that may be formed in the form of miscible blends (e.g., by co-extrusion or by reaction, including, for example, transesterification). The term "(co)polymer" includes random, block, and star-shaped (e.g., dendritic) (co)polymers.

[0029] 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.

[0030] The term "optically transparent" refers to a material that does not exhibit noticeable distortion, haze, or defects that are not visible to the naked eye at a distance of about 1 meter, preferably about 0.5 meters.

[0031] The term "cover" is used to describe the position of a layer relative to a substrate, paired layers, or different layers. "Cover" means that the layer is located on top of the substrate, paired layers, or different layers, but is not necessarily adjacent to or in contact with the substrate, paired layers, or different layers, although in some embodiments the layer may be in direct contact with the substrate, paired layers, or different layers.

[0032] The term "paired layer" refers to a pair of layers comprising a (co)polymer layer and an oxide layer covering the (co)polymer layer. Multiple paired layers refer to two or more pairs of layers, wherein each layer comprises a (co)polymer layer and an oxide layer covering the (co)polymer layer.

[0033] The term "layer" refers to a single layer in a multilayer film.

[0034] The term "attachment" encompasses both direct attachment and the option of having one or more layers between two attached layers, in the context of two layers being attached.

[0035] The term "refractive index" is a dimensionless quantity and a measure of the ability of a medium through which light passes to bend or reflect. When a beam of light passes through two materials with different refractive indices, a portion of the incident light is reflected. Therefore, optimal reflection can be achieved by constructing a material with a suitable refractive index composition. Accordingly, in one aspect, this disclosure provides a retroreflective article having a refractive index difference of 1.49 or greater, 1.51, 1.53, 1.55, 1.57, or 1.59 or greater from a first principal surface of the retroreflective article to a relative principal surface of the retroreflective article.

[0036] Various exemplary embodiments of this disclosure will now be described. Various modifications and alterations may be made to the exemplary embodiments of this disclosure without departing from the spirit and scope of this disclosure. Therefore, it should be understood that the embodiments of this disclosure are not limited to the exemplary embodiments described below, but are subject to the limiting factors shown in the claims and any equivalents thereof.

[0037] Retroreflective products

[0038] In a first aspect, this disclosure provides a retroreflective article. The retroreflective article includes an retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface opposite to a main surface; and an antireflective layer having a first main surface and an opposite second main surface. The second main surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

[0039] The retroreflective article disclosed herein refers to an arrangement or construction of layered materials that constitute a specific optical shape, optical components and / or structure capable of retroreflecting incident light.

[0040] Figure 1 A retroreflective article (100) of this disclosure is depicted. The retroreflective article includes a retroreflective layer (110) and an antireflective layer (120). The retroreflective layer (110) includes a plurality of surface structural elements that collectively form a structured surface (110b) opposite to a main surface (110a). The antireflective layer (120) includes a first main surface (120b) and an opposing second main surface (120a). The opposing second main surface (120a) of the antireflective layer (120) is attached to the structured surface (110b) of the retroreflective layer.

[0041] Figure 2 A retroreflective article (200) of this disclosure is depicted. The retroreflective article includes a retroreflective layer (210) and an antireflective layer (220). The retroreflective layer (210) includes a plurality of surface structural elements that collectively form a structured surface (210b) opposite to a main surface (210a). The antireflective layer (220) includes a first main surface (220b) and an opposite second main surface (220a). The retroreflective article also includes an adhesive layer (230) disposed between the retroreflective layer (210) and the antireflective layer (220). The adhesive layer (230) includes an optically transparent adhesive. The adhesive layer (230) also includes at least one of the following: a first UV absorber or a first hindered amine light stabilizer (HALS).

[0042] Figure 3A retroreflective article (300) of this disclosure is depicted. The retroreflective article includes a retroreflective layer (310) and an antireflective layer (320). The retroreflective layer (310) includes a plurality of surface structural elements that collectively form a structured surface (310b) opposite to a main surface (310a). The antireflective layer (320) includes a first main surface (320b) and an opposite second main surface (320a). The retroreflective article also includes a barrier layer (330) disposed between the retroreflective layer (310) and the antireflective layer (320). The barrier layer (330) includes a metal oxide layer. The barrier layer (330) further includes: at least one paired layer consisting of a (co)polymer layer and an inorganic layer covering the (co)polymer layer; an outer (co)polymer layer covering the at least one paired layer; and optionally at least one outer inorganic layer covering the outer (co)polymer layer. Each (co)polymer layer of the barrier layer (330) further includes at least one of the following: a second UV absorber or a second hindered amine light stabilizer (HALS).

[0043] Figure 4 A retroreflective article (400) of this disclosure is depicted. The retroreflective article includes a retroreflective layer (410) and an antireflective layer (420). The retroreflective layer (410) includes a plurality of surface structural elements that collectively form a structured surface (410b) opposite a main surface (410a). The antireflective layer (420) includes a first main surface (420b) and an opposite second main surface (420a). The second main surface (420a) of the antireflective layer (420) is attached to the structured surface (410b) of the retroreflective layer. The retroreflective article also includes an optically clear adhesive (430) attached to the first main surface (420b) of the antireflective layer (420). The optically clear adhesive typically comprises at least one polyisobutylene resin and a polyfunctional (meth)acrylate monomer. For example, suitable optically clear adhesives are described in detail in U.S. Patent No. 8,232,350 (Fujita et al.).

[0044] Figure 5A retroreflective article (500) of this disclosure is depicted. The retroreflective article includes a retroreflective layer (510) and an antireflective layer (520). The retroreflective layer (510) includes a plurality of surface structure elements that collectively form a structured surface (510b) opposite a main surface (510a). The antireflective layer (520) includes a first main surface (520b) and an opposite second main surface (520a). The second main surface (520a) of the antireflective layer (520) is attached to the structured surface (510b) of the retroreflective layer. In some embodiments, the antireflective layer (520) includes a porous gradient layer or a quarter-wavelength antireflective layer. The antireflective layer (520) includes a structured antireflective layer having a structured first main surface (530). In some cases, the structured first main surface (530) includes microstructures. In some cases, the structured antireflective layer comprises a matrix and a nanoscale dispersed phase, and the structured first master surface comprises a microstructured surface having anisotropic surfaces with random nanostructures. Such a structured first master surface (530) may have a structured skip-tooth pattern (540) with micropeaks (540a) and microgaps (540b). Optionally, the antireflective layer (520) comprises a fluoropolymer material.

[0045] Figure 6 A schematic cross-sectional view of another exemplary embodiment of the retroreflective article according to the present disclosure is depicted, wherein the antireflective layer has a skip-tooth pattern and two adhesive layers are attached to a substrate. More specifically, the retroreflective article (600) includes a retroreflective layer (610) and an antireflective layer (620). The retroreflective layer (610) includes a plurality of surface structure elements that collectively form a structured surface (610b) opposite to a main surface (610a). The antireflective layer (620) includes a first main surface (620b) and an opposing second main surface (620a). The second main surface (620a) of the antireflective layer (620) is attached to the structured surface (610b) of the retroreflective layer. The antireflective layer (620) includes a structured antireflective layer having a structured first main surface (630). In some cases, the structured first main surface (630) includes microstructures. Such a structured first primary surface (630) may have a structured skip-tooth pattern (640) with micro-peaks (640a) and micro-gap (640b). The retroreflective article (600) also includes an adhesive layer 650 in the form of multiple adhesive strips, which attaches the antireflective layer (620) to the retroreflective layer (610). The retroreflective article (600) also includes another adhesive layer (660) that adheres the retroreflective article (600) to a substrate (670) (e.g., greenhouse glass, building windows, etc.). In some cases, the adhesive layer (660) is an optically transparent adhesive.

[0046] The retroreflective article includes a retroreflective layer comprising a plurality of surface structural elements that together form a structured surface. Each surface structural element of the retroreflective layer includes at least one shape having a cross-section in a plane parallel to the opposing main surface of the retroreflective layer, which can be selected from a group consisting of ellipses, semicircles, oblongs, and polygons. The surface structural elements of the retroreflective layer also include at least one shape selected from a group consisting of: cubic angles, hemispheres, quarter-spheres, prisms, pyramids, and truncated cubic angles. Therefore, the structured surface is non-planar.

[0047] Suitable examples of retroreflective structured surfaces can be found in reflective sheets commercially available from 3M Company, St. Paul, MN, under the trade names “3M Diamond Grade DG3 Reflective Sheeting”, “3M Diamond Grade Conspicuity”, “3M Engineer Grade Reflective Sheeting”, “3M Scotchlite Reflective Tape”, and “3M Flexible Prismatic Cone Sheeting”.

[0048] The structured surface of the retroreflective layer has multiple tiny surface structural elements arranged to reflect a significant portion of the incident light and transmit a significant portion of the light. The reflectivity of the surface is primarily altered through this variation in local geometry. Useful structures include cubic prisms, linear prisms, conical prisms with triangular, square, hexagonal, or other polygonal bases, cones, hemispheres, quarterspheres, truncated cubic prisms, and ellipsoids, which can take the form of protrusions from the surface or recesses extending into the surface. Hemispheres can be created using glass beads protruding from the surface. The size, shape, geometry, orientation, and spacing of the structures, as well as the use of a variety of different structures (e.g., different sizes, shapes, geometries, orientations, etc.) and spacing densities, can be selected to optimize the performance of the optical assembly or otherwise provide the desired effect. Individual structures can be symmetrical and / or asymmetrical. The structured surface can be homogeneous and / or non-homogeneous, and in the latter case, the position and size of the structures can be random or pseudo-random. In this context, "homogeneous" is understood to mean that the structured surface comprises a repeating structural pattern. Disrupting regular features through periodic or pseudo-random variations in size, shape, geometry, orientation, and / or spacing can be used to adjust the color and / or brightness uniformity of the retroreflective layer. In some cases, it may be advantageous to distribute smaller and larger structures and position the retroreflective layer such that the smaller structures are generally aligned with the light source, while the larger structures are located elsewhere. In some embodiments, these structures may be tightly encapsulated to minimize the matrix between structures (including arrangements where there is essentially no matrix between structures). In some implementations, it may be necessary to control the matrix region to modulate the amount of light passing through the retroreflective layer.

[0049] Examples of suitable structured surfaces include commercial one-dimensional (linear) prism polymer films, such as those marketed by 3M Inc. in St. Paul, Minnesota, under the trade names “VIKUITI BRIGHTNESS ENHANCEMENT FILM,” “VIKUITI TRANSMISSIVE RIGHT ANGLE FILM,” “VIKUITI IMAGE DIRECTING FILM,” and “VIKUITIOPTICAL LIGHTING FILM,” as well as conventional columnar linear lens arrays.

[0050] Other examples of suitable structured surfaces (where the structured surface has two-dimensional features) include cubic corner surface configurations, such as those described in U.S. Patent No. 4,588,258 (Hoopman), U.S. Patent No. 4,775,219 (Appeldorn et al.), U.S. Patent No. 5,138,488 (Szczech), U.S. Patent No. 5,122,902 (Benson), U.S. Patent No. 5,450,235 (Smith et al.), and U.S. Patent No. 5,840,405 (Shusta et al.); Inclined prism surface configurations, such as those described in U.S. Patent No. 6,287,670 (Benson et al.) and U.S. Patent No. 6,280,822 (Smith et al.); structured surface films, such as those described in U.S. Patent No. 6,752,505 (Parker et al.) and U.S. Patent Application Publication No. 2005 / 0024754 (Epstein et al.); and beaded sheets, such as those described in U.S. Patent No. 6,771,335 (Kimura et al.), the disclosures of which are incorporated herein by reference.

[0051] In some embodiments, the retroreflective article of this disclosure exhibits a refractive index difference of 1.49 or greater, 1.51, 1.53, 1.55, 1.57, or 1.59 or greater from one primary surface of the retroreflective article to the relative primary surface of the retroreflective article.

[0052] Adhesive layer

[0053] In some embodiments, the retroreflective article of this disclosure includes at least one adhesive layer. The adhesive layer facilitates adhesion of the layers of the retroreflective article and provides stability to the layered structure of the retroreflective article even when exposed to outdoor / environmental conditions. In some cases, the adhesive layer is disposed between the retroreflective layer and the antireflective layer. Optionally, the adhesive layer is an adhesive disposed on the outer surface of the retroreflective article to attach the article to a substrate (e.g., a window). For example, the adhesive may be disposed on the flat main surface of the retroreflective layer (opposite to the structured surface), the main surface of the antireflective layer, etc. In some cases, the adhesive layer used in any embodiment of the retroreflective article according to this disclosure is a discontinuous layer, for example, it may be in the form of multiple adhesive strips, dots, or other shapes, rather than a continuous layer.

[0054] Polymer materials used for adhesive layers include thermoplastic and thermosetting resins. Suitable thermoplastics include, but are not limited to: polyethylene terephthalate (PET), crosslinked polysiloxanes, silicone thermoplastic polymers, crosslinked polyurethanes, thermoplastic polyurethanes, crosslinked (meth)acrylates, polymethyl methacrylate (PMMA), copolymers of ethyl acrylate and methyl methacrylate (coPMMA), polyimides, cyclic olefin copolymers, cyclic olefin polymers, polycarbonates, polyisobutylene (PIB), polyvinyl butyrate, butyl rubber (BR), epoxy resins, thiols, thiolenes, polystyrene, acrylonitrile butadiene styrene, polyvinyl chloride, polyvinylidene chloride, polyacrylate, polyvinyl acetate, polyamides, polyimides, polypropylene, polyesters, polyethylene, poly(methyl methacrylate), polyethylene naphthalate, styrene-acrylonitrile, silicone-polydiacetamide polymers, cyclic olefin copolymers, thermoplastic elastomers, etc.

[0055] In some embodiments, the adhesive layer includes polyethylene terephthalate (PET), crosslinked polysiloxane, silicone thermoplastic polymer, crosslinked polyurethane, thermoplastic polyurethane, crosslinked (meth)acrylate, polymethyl methacrylate (PMMA), copolymer of ethyl acrylate and methyl methacrylate (coPMMA), polyimide, cyclic olefin copolymer, cyclic olefin polymer, polycarbonate, polyisobutylene (PIB), polyvinyl butyrate, butyl rubber (BR), epoxy resin, thiol, thioolefin, or combinations thereof.

[0056] In some embodiments, the adhesive layer comprises an optically clear adhesive. The optically clear adhesive comprises at least one polyisobutylene resin and a polyfunctional (meth)acrylate monomer. In some embodiments, the adhesive comprises a polyisobutylene resin with a weight-average molecular weight greater than about 1,000,000 g / mol, or greater than about 400,000 g / mol, or greater than about 300,000 g / mol; and a polyfunctional (meth)acrylate monomer; and the adhesive is substantially free of tackifiers. The polyisobutylene may comprise at least about 50% by weight of the total weight of the adhesive. The polyfunctional (meth)acrylate monomer may also be included in the adhesive of this embodiment. When such a monomer is used, the adhesive may comprise about 60 to about 90% by weight of the polyisobutylene resin; and about 10% to about 20% by weight of the polyfunctional (meth)acrylate monomer; all relative to the total weight of the adhesive.

[0057] In some embodiments, the adhesive comprises a first polyisobutylene resin with a weight-average molecular weight greater than about 300,000 g / mol; and a second polyisobutylene resin with a weight-average molecular weight less than about 100,000 g / mol, wherein the adhesive is substantially free of tackifiers. In this embodiment, the weight-average molecular weight of the first isobutylene resin may be greater than about 400,000 g / mol. In this embodiment, the weight-average molecular weight of the first isobutylene resin may also be greater than about 1,000,000 g / mol. The first polyisobutylene may comprise at least about 50% by weight of the total weight of the adhesive. The adhesive may comprise: about 50% to about 80% by weight of the first polyisobutylene resin; about 10% to about 30% by weight of the second polyisobutylene resin; and about 10% to about 20% by weight of the polyfunctional (meth)acrylate monomer; all of which are relative to the total weight of the adhesive.

[0058] In some embodiments, the adhesive comprises a second polyisobutylene resin with a weight-average molecular weight of less than about 300,000 g / mol; a polyfunctional (meth)acrylate monomer; and a tackifier, wherein the adhesive does not contain a first polyisobutylene resin with a weight-average molecular weight greater than about 300,000 g / mol. The weight-average molecular weight of the second isobutylene resin may be less than about 100,000 g / mol. The adhesive of this embodiment may comprise: about 10% to about 50% by weight of the second polyisobutylene resin; about 10% to about 40% by weight of the polyfunctional (meth)acrylate monomer; about 0% to about 60% by weight, or about 30% to about 60% by weight of the tackifier; all of which are relative to the total weight of the adhesive.

[0059] In some embodiments, the adhesive comprises a first polyisobutylene resin with a weight-average molecular weight greater than about 300,000 g / mol, wherein the first polyisobutylene resin comprises 20% by weight or less of the total weight of the adhesive; a second polyisobutylene resin with a weight-average molecular weight less than about 300,000 g / mol; a polyfunctional (meth)acrylate monomer; and a tackifier. In this embodiment, the weight-average molecular weight of the first isobutylene resin may be greater than about 1,000,000 g / mol. The adhesive may include: about 10% to about 30% by weight of the second polyisobutylene resin; about 10% to about 30% by weight of the polyfunctional (meth)acrylate monomer; about 0% to about 60% by weight, or about 40% to about 60% by weight of the tackifier; all of which are relative to the total weight of the adhesive.

[0060] The first and second polyisobutylene resins are typically resins having a polyisobutylene resin backbone in the main chain or side chains. In some embodiments, the first and second polyisobutylene resins are essentially homopolymers of isobutylene, for example, polyisobutylene resins available under the trade names OPPANOL (BASF AG) and GLISSOPAL (BASF AG). In some embodiments, the first and second polyisobutylene resins comprise copolymers of isobutylene, for example, synthetic rubbers wherein isobutylene is copolymerized with another monomer. The synthetic rubber includes butyl rubber, which is a copolymer of most isobutylene and a small amount of isoprene, for example, butyl rubber available under the trade names VISTANEX (Exxon Chemical Co.) and JSR BUTYL (Japan Butyl Co., Ltd.). The synthetic rubber also includes copolymers of most isobutylene with n-butene or butadiene. In some embodiments, a mixture of isobutylene homopolymer and butyl rubber may be used, i.e., the first polyisobutylene comprises a homopolymer of isobutylene and the second polyisobutylene comprises butyl rubber; or the first polyisobutylene comprises butyl rubber and the second polyisobutylene comprises a homopolymer of isobutylene. The first and second polyisobutylene resins may each comprise more than one resin.

[0061] Polyisobutylene resins typically possess solubility parameters (SP values, an index used to characterize the polarity of compounds) similar to those of hydrogenated alicyclic hydrocarbon resins, and exhibit good compatibility (i.e., miscibility) with hydrogenated alicyclic hydrocarbon resins (if used), enabling the formation of transparent films. Furthermore, polyisobutylene resins have low surface energy, allowing adhesives to spread onto the substrate and minimizing interfacial porosity. Additionally, their low glass transition temperature and moisture permeability make polyisobutylene resins suitable as base resins for adhesives.

[0062] Polyisobutylene resins can possess the desired viscoelasticity, which is generally used to impart the required flowability to adhesives. A strain rheometer can be used to determine the elastic (storage) modulus G' and the viscous (loss) modulus G'' at various temperatures. G' and G'' can then be used to determine the ratio tan(δ) = G'' / G. Generally, the higher the tan(δ) value, the more viscous the material, and the lower the tan(δ) value, the more elastic the material. In some embodiments, the polyisobutylene resin is selected such that when the composition is at a temperature of about 70°C to about 110°C, the adhesive has a tan(δ) value of at least about 0.5 at relatively low frequencies. In this way, the adhesive can flow sufficiently over uneven surfaces with little or no air trapping.

[0063] When used in combination with polyfunctional (meth)acrylate monomers without any tackifiers, the required viscoelasticity of the adhesive can be obtained by using a first polyisobutylene resin with a weight-average molecular weight greater than about 300,000 g / mole or greater than 1,000,000. Furthermore, the required viscoelasticity of the adhesive can be obtained when the first polyisobutylene accounts for more than about 50% by weight of the total adhesive weight.

[0064] The multifunctional (meth)acrylate monomers of the adhesive can be saturated or unsaturated and may include aliphatic, alicyclic, aromatic, heterocyclic, and / or epoxy functional groups. In some embodiments, saturated long-chain alkyl (meth)acrylates, cycloaliphatic (meth)acrylates, (meth)acrylate / epoxy monomers, or combinations thereof may be used as monomers because they can enhance the miscibility of the polyisobutylene resin and optional tackifiers. The multifunctional (meth)acrylate monomers may be unsubstituted or substituted with multiple groups, such as hydroxyl or alkoxy groups.

[0065] Exemplary long-chain alkyl (meth)acrylates include, but are not limited to, octyl acrylate (meth)acrylate, stearyl alcohol (meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, and hydrogenated polybutadiene di(meth)acrylate resin. Exemplary cycloaliphatic (meth)acrylates include, but are not limited to, isobornyl (meth)acrylate, tetramethylpiperidinyl methacrylate, pentamethylpiperidinyl methacrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, tricyclodecanediol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, and (meth)acrylated epoxy resin.

[0066] In some embodiments, polyfunctional (meth)acrylate monomers having two, three, four, or even more than four (meth)acrylate groups may be used. Those skilled in the art will also understand that mixtures of polyfunctional (meth)acrylate monomers may be utilized.

[0067] Polyfunctional (meth)acrylate monomers can be selected to optimize the adhesion and wettability of adhesives relative to polyisobutylene resins. Polyfunctional (meth)acrylate monomers can increase the adhesion and retention strength of adhesives because the monomers cure to form a resin.

[0068] Typically, the adhesive layer of this disclosure also includes a first UV absorber or a first hindered amine light stabilizer (HALS).

[0069] It is worth noting that the term "ultraviolet absorber" refers to a material that absorbs light with wavelengths below 400 nm but does not emit light in the range of 400 nm to 1200 nm. Examples of ultraviolet absorbers include, but are not limited to, benzotriazole compounds, oxazolamide compounds, and benzophenone compounds. When used, ultraviolet absorbers can be applied in an amount of approximately 0.01% to 3% by weight based on the total amount of binder in the matrix.

[0070] Examples of other UV absorbers include, but are not limited to, 2-(2′-hydroxyphenyl)benzotriazole, such as 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3′,5′-di ...2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1, tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole, 2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole, 2-(3′,5′-di-tert-pentyl-2′-hydroxyphenyl)benzotriazole, 2-(3′,5′-bis(α,α-dimethylphenyl)benzotriazole 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octoxycarbonylethyl)phenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, and 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole. UV absorbers also include compounds belonging to the groups of 4-hydroxybenzoates, substituted and unsubstituted benzoates, acrylates, and nickel complexes. For information on such UV absorbers, see U.S. Patent Application Publication No. 2008 / 0033080 (Dietmar et al.).

[0071] Examples of hindered amine light stabilizers include, but are not limited to, bis(2,2,6,6-tetramethyl-4-piperidinyl) succinate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, condensates of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine with succinic acid, and linear or cyclic condensates of N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine with 4-tert-octylamino-2,6-dichloro-1,3,5-triazine. Tris(2,2,6,6-tetramethyl-4-piperidinyl) triacetate, tetra(2,2,6,6-tetramethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylic acid tetra(2,2,6,6-tetramethyl-4-piperidinyl) ester, 1,1′-(1,2-ethylenediyl)bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonic acid bis(1,2,2-) ,6,6-pentamethylpiperidinyl) ester, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, sebacic acid bis(1-octoxy-2,2,6,6-tetramethylpiperidinyl) ester, succinate bis(1-octoxy-2,2,6,6-tetramethylpiperidinyl) ester, N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine linear or cyclic condensation Condensations of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidinyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, condensations of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidinyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, and 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4].5] Decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)pyrrolidine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidinyl)pyrrolidine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, and a condensation product of N,N′-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine. The condensation products of 1,2-bis(3-aminopropylamino)ethane with 2,4,6-trichloro-1,3,5-triazine and 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Registry No. [136504-96-6]); condensation products of 1,6-hexanediamine with 2,4,6-trichloro-1,3,5-triazine and N,N-dibutylamine with 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Registry No. [192268-64-7]); and N-(2,2,6,6-tetramethyl-4-piperidinyl) - Dodecyl succinimide, N-(1,2,2,6,6-pentamethyl-4-piperidinyl)-dodecyl succinimide, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decane, reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decane with epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-piperidinoxycarbonyl)-2-(4-methoxybenzene) Hindered amine light stabilizers also include compounds belonging to the groups of oxalamide, 2-(2-hydroxyphenyl)-1,3,5-triazine, metal passivating compounds, phosphites, hypophosphite esters, hydroxylamine, and nitroxide radicals; methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidinyl)siloxane; maleic anhydride-α-olefin copolymers with 2,2,6,6-tetramethyl-4-aminopiperidine or 1,2,2,6,6-pentamethyl-4-aminopiperidine; HA-6). Regarding hindered amine light stabilizers, see U.S. Patent Application Publication No. 2008 / 0033080 (Dietmar et al.). Hindered amine light stabilizers can be used in amounts ranging from approximately 0.01% to 3% by weight based on the total amount of binder in the matrix.

[0072] Barrier layer

[0073] In some embodiments, the retroreflective article of this disclosure includes a barrier layer. The barrier layer includes a metal oxide layer. In some embodiments, the metal oxide layer includes at least one of the following: titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, silica aluminum oxide, or niobium oxide. In selected embodiments, the thickness of the metal oxide layer is from 15 nanometers to 60 nanometers (nm). The thickness of the metal oxide layer is preferably greater than 15 nm, or greater than 20 nm, or greater than 25 nm, or greater than 30 nm, or greater than 35 nm; or less than 60 nm, or less than 55 nm, or less than 50 nm, or less than 45 nm, or less than 40 nm.

[0074] The barrier layer includes at least one paired layer. The paired layer includes a (co)polymer layer and an inorganic layer covering the (co)polymer layer; an outer (co)polymer layer covering the at least one paired layer; and optionally at least one outer inorganic layer covering the outer (co)polymer layer. The at least one paired layer can be a single paired layer or multiple paired layers, and the multiple paired layers can optionally be two, three, four, five, six, or more paired layers.

[0075] In some cases, each of the at least one pair of layers and the outer layer of the polymer comprises a polymer selected from the following: olefin polymers, (meth)acrylate polymers, urethane polymers, silicone polymers, or combinations thereof.

[0076] The (co)polymer layer can be formed from a variety of organic materials or compounds using various processes. After application, the (co)polymer layer can be crosslinked in situ. In one embodiment, the (co)polymer layer can be formed by flash evaporation, vapor deposition, and (co)polymerization of monomers using, for example, heating, plasma, UV radiation, or electron beams. Exemplary monomers used in this method include volatile (meth)acrylate monomers.

[0077] In specific implementations, volatile acrylate monomers are used. Suitable (meth)acrylates will have a molecular weight low enough to allow flash evaporation and high enough to allow condensation on the substrate. Organic materials or compounds may also be vaporized using any of the methods described below for vaporizing metal alkoxides.

[0078] If desired, the (co)polymer layer may be applied using conventional methods such as plasma deposition, solution coating, extrusion coating, roll coating (e.g., gravure roll coating), or spray coating (e.g., electrostatic spray coating), and crosslinking or (co)polymerization may be performed if necessary. The desired chemical composition and thickness of the additional layer will depend in part on the properties of the substrate and the intended purpose of the layer. Coating efficiency can be improved by cooling the substrate.

[0079] Exemplary organic compounds include esters, vinyl compounds, alcohols, carboxylic acids, acid anhydrides, halogens, thiols, amines, and mixtures thereof. Non-limiting examples of esters include (meth)acrylates, which can be used alone or in combination with other polyfunctional or monofunctional (meth)acrylates. Exemplary (meth)acrylates include hexanediol diacrylate, ethoxyethyl acrylate, phenoxyethyl acrylate, cyanoethyl acrylate, isobornyl acrylate, octadecyl acrylate, isodecanyl acrylate, lauryl acrylate, β-carboxyethyl acrylate, tetrahydrofurfuryl acrylate, dinitrile acrylate, pentafluorophenyl acrylate, nitrobenzene acrylate, phenoxyethyl acrylate, 2,2,2-trifluoromethyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and tripropylene glycol. Diacrylates, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycol diacrylate, bisphenol A epoxy diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, phenylthioethyl acrylate, naphthoxyethyl acrylate, IRR-214 cyclic diacrylate purchased from UCB Chemicals, epoxy acrylate RDX80095 purchased from Rad-Cure Corporation, the corresponding methacrylates of the acrylates listed above, and mixtures thereof. Exemplary vinyl compounds include vinyl ethers, styrene, vinylnaphthalene, and acrylonitrile. Exemplary alcohols include hexanediol, naphthalene glycol, and hydroxyethyl methacrylate. Exemplary carboxylic acids include phthalic acid and terephthalic acid, and (meth)acrylic acid. Exemplary acid anhydrides include phthalic anhydride and glutaric anhydride. Exemplary haloacyl compounds include adipic acid dichloro and succinyl chloride. Exemplary thiols include ethylene glycol dithioglycolate and phenylthioethyl acrylate. Exemplary amines include ethylenediamine and hexane-1,6-diamine.

[0080] Typically, each inorganic layer in at least one pair of layers and at least one optional outer oxide layer covering the outer (co)polymer layer comprises an inorganic material selected from the following: silicon oxide, silicon alumina oxide, silicon oxynitride, gallium oxide, magnesium oxide, niobium oxide, titanium dioxide, yttrium oxide, zinc oxide, tin oxide, nickel oxide, aluminum-doped zinc oxide, indium tin oxide, zirconium oxynitride, hafnium oxide, aluminum oxide, aluminum-doped silicon dioxide, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or combinations thereof.

[0081] The outer (co)polymer layer covers at least one paired layer, which may be multiple paired layers. Preferably, the outer (co)polymer layer is cross-linked.

[0082] In some embodiments, at least one (co)polymer layer includes at least one UV absorber. In other exemplary embodiments, at least one (co)polymer layer further includes a hindered amine light stabilizer (HALS).

[0083] In some exemplary embodiments, the outer (co)polymer layer comprises an olefin (co)polymer selected from the following: low-density polyethylene, linear low-density polyethylene, ethylene vinyl acetate, polyethylene methyl acrylate, polyethylene octene, polyethylene propylene, polyethylene butene, polyethylene maleic anhydride, polymethylpentene, polyisobutylene, polyisobutylene, polyethylene propylene diene, cyclic olefin (co)polymers, and blends thereof.

[0084] The outer (co)polymer layer covering the at least one pair of layers may advantageously include at least one optional protective layer, a multilayer optical film, an optional outer oxide layer covering the outer (co)polymer layer, an tackifying layer, a heat-sealing encapsulation film, an additive, or a combination thereof.

[0085] Optional protective layer

[0086] Other functional layers or coatings that can be added to the barrier layer include one or more optional layers to make the film more rigid. The topmost layer may optionally be a suitable protective layer. 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. Optional protective layers can also be formed by monomer flash evaporation, vapor deposition, and crosslinking as described above. Volatile (meth)acrylate monomers are suitable for use in such protective layers. In a specific embodiment, volatile acrylate monomers are used.

[0087] Optional multilayer optical films

[0088] The barrier layer, preferably an outer (co)polymer layer, may optionally comprise a multilayer optical film. Generally, the optional multilayer optical film described herein comprises at least three layers (typically ranging from three to 2000 or more layers). The multilayer optical film described herein can be manufactured using common processing techniques, such as those described in U.S. Patent No. 6,783,349 (Neavin et al.), the entire disclosure of which is incorporated herein by reference.

[0089] The optional multilayer optical film described herein comprises at least a plurality of alternating first and second optical layers that collectively reflect at least 30% (in some embodiments, at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or even at least 90%) of incident infrared (IR) light (i.e., any light with a wavelength range from 700 nm to less than 1000 micrometers) at incident angles of at least 0°, 30°, 45°, 60°, 65%, 70%, 75%, 80%, 85%, or even at least 90%) of the incident light at incident angles of at least 0°, 30°, 45°, 60°, or 75°, and cover a wavelength reflection bandwidth of at least 30 nm, with wavelength ranges from at least 100 nm to 350 nm (in some embodiments, at least 180 nm to 350 nm, or even at least 200 nm to 350 nm).

[0090] In some embodiments, the multilayer optical film described herein has an IR transmission band edge in the range of 10% to 90% transmittance, with a span of less than 20 nm (in some embodiments, less than 15 nm or even less than 10 nm).

[0091] Optional outer oxide layer covering the outer (co)polymer layer

[0092] In some exemplary embodiments, the barrier layer advantageously comprises at least one external oxide layer, preferably a metal oxide layer, which covers the external (co)polymer layer. In some exemplary embodiments, the at least one external oxide layer covering the external (co)polymer layer comprises at least one layer composed of hafnium oxide, zirconium oxynitride, silicon oxide, gallium oxide, indium tin oxide, niobium oxide, titanium dioxide, zinc oxide, tin oxide, nickel oxide, aluminum silicon oxide, aluminum-doped zinc oxide, or combinations thereof. In some such embodiments, the barrier layer exhibits a static decay time of less than 90 minutes, 70 minutes, 60 minutes, 50 minutes, 40 minutes, 30 minutes, 20 minutes, 10 minutes, or even less than 1 minute, according to static decay time testing.

[0093] In some exemplary embodiments, the at least one external oxide layer advantageously comprises a plurality of external oxide layers composed of hafnium oxide, zirconium oxynitride, silicon oxide, gallium oxide, indium tin oxide, tin oxide, nickel oxide, aluminum silicon oxide, niobium oxide, titanium dioxide, zinc oxide, aluminum-doped zinc oxide, or combinations thereof, and a top layer composed of silicon oxide. In some exemplary embodiments, any oxide layer can be formed by the hydrolysis of a metal alkoxide, as further described below. Suitable metal alkoxides for forming layers on a substrate are compounds that are volatile and condense on the substrate. After condensation, the alkoxide can be cured by reacting with water to form a barrier film. Exemplary metal alkoxide compounds may have the general formula R. 1 x M-(OR 2 ) y-x , where each R 1 Independently is (C1-C 20 alkyl, (C3-C8)cycloalkyl, (C2-C7)heterocyclic, (C2-C7)heterocyclic, (C1-C8)alkylene-, (C6-C 10 )Aryl, (C6-C 10 )aryl (C1-C8)alkylene-, (C5-C9)heteroaryl or (C5-C9)heteroaryl (C1-C8)alkylene-, and each R 2 Independently, it is a (C1-C6) alkyl group, optionally substituted with a hydroxyl group or an oxo group. R 1 The group may optionally be substituted by one or more substituents, wherein each of these substituents is independently oxo, halogenated, or -OR. a -SR a , cyano, nitro, trifluoromethyl, trifluoromethoxy, (C3-C8)cycloalkyl, (C2-C7) heterocyclic or (C2-C7) heterocyclic (C1-C8) alkylene-, (C6-C 10 )Aryl, (C6-C 10 aryl(C1-C8)alkylene-, (C5-C9)heteroaryl, (C5-C9)heteroaryl(C1-C8)alkylene-, -CCO2R a R a C(=O)O-、R a C(=O)-、-OCO2R a R b R c NC(=O)O-、R a C(=O)N(R b )-、R b R c N-. R b R c NC(=O)-、R a C(=O)N(Rb )-、R b R c NC(=O)N(R b )-、R b R c NC(=S)N(R b )-、-OPO3R a ROC(=S)-, R a C(=S)-、-SSR a R a S(=O)-、-NNR b -OPO2R a Or two Rs 1 Groups can form rings together with the atoms they are attached to. R a R b and R c Each is independently hydrogen, (C1-C8)alkyl, or substituted (C1-C8)alkyl, wherein the substituents include 1, 2, or 3 (C1-C8)alkoxy, (C3-C8)cycloalkyl, (C1-C8) alkylthio, amino, aryl, or aryl (C1-C8) alkylene, or R b and R c They can form rings together with the nitrogen atoms to which they are attached. Exemplary rings include pyrrolidinyl, piperidinyl, morpholinyl, or thiomorpholinyl. Exemplary halogen groups include fluorine, chlorine, or bromine. R 1 and R 2 Alkyl groups can be either straight-chain or branched independently. R 1The group may be independently and optionally interrupted by heteroatoms (e.g., oxygen, sulfur, or nitrogen). M represents a metal, x is 1, 2, 3, 4, or 5, and y is the valence number of the metal (e.g., y can be 3 for aluminum, y can be 4 for titanium and zirconium, and may vary depending on the oxidation state of the metal), provided that y - x > 1 (e.g., at least one alkoxy group must be attached to a metal atom). Exemplary metals include aluminum, antimony, arsenic, barium, bismuth, boron, cerium, gadolinium, gallium, germanium, hafnium, indium, iron, lanthanum, lithium, magnesium, molybdenum, neodymium, phosphorus, silicon, sodium, strontium, tantalum, thallium, tin, titanium, tungsten, vanadium, yttrium, zinc, and zirconium, or mixtures thereof. Non-limiting examples of specific metal alkoxides include tetra(methoxy)titanate, tetra(ethoxy)titanate, tetra(isopropoxy)titanate, tetra(n-propoxy)titanate, tetra(butoxy)titanate, methyltriacetoxysilane, fluorinated silanes (e.g., fluorinated polyether silanes disclosed in U.S. Patent No. 6,991,826), tetra(n-propoxy)zirconate, and mixtures thereof. Other examples include volatile prepolymer (co)polymer forms of the above-described metal alkoxides, including dimers, trimers, and longer oligomers, including polydimethoxysiloxanes and polybutyltitanate. The additional metal alkoxides include methoxy, ethoxy, n-propoxy, butoxy, acetoxy, and isopropoxy functionalized metal atoms, as well as pre- (co)polymerized forms of these metal alkoxides, including tetra(ethoxy)titanate, tetra(n-propoxy)titanate, tetra(isopropoxy)titanate, methyltriacetoxysilane, fluorinated silane, polydimethoxysilane, and tetra(n-propoxy)zirconate.

[0094] In some embodiments, the metal alkoxide and optionally an organic material or compound may be evaporated together to form a mixed vapor, or they may be evaporated separately and mixed in the gas phase. In applications where the alkoxide is immiscible with the organic compound (or another metal alkoxide), it may be advantageous to mix these materials in the vapor phase after separate evaporation. The alkoxide and organic compound may condense onto the substrate at temperatures below the vapor flow condensation point.

[0095] The metal alkoxide and optionally an organic material or compound can be vaporized using a variety of methods known in the art. Exemplary methods include evaporation (e.g., flash evaporation, using techniques such as those disclosed in U.S. Patent Nos. 4,954,371 and 6,045,864), sublimation, etc. Evaporation can be carried out under vacuum or atmospheric pressure. A (optionally heated) carrier gas flow can be added to the evaporator to reduce the partial pressure of the metal alkoxide vapor or increase the evaporation rate. The alkoxide can condense onto the substrate at a temperature below the condensation point of the vapor flow.

[0096] The condensed alkoxide layer is cured by contacting it with water. For example, the layer can be contacted with water vapor, liquid water, or plasma containing water vapor. Heating can enhance curing. Any suitable source (e.g., an infrared heater or a catalytic combustion heater) can be used to provide heat. The catalytic combustion heater can also provide water vapor. Additional energy can be provided during curing by UV or vacuum UV light input into the condensed alkoxide layer.

[0097] The curing reaction can be accelerated using a vaporizable catalyst. Exemplary catalysts include organic acids such as acetic acid and methanesulfonic acid, photoacid generators such as triphenylsulfonium and diphenyliodine compounds, or basic materials and photoalkali generators such as ammonia. The photocatalyst can be activated by exposure to UV light. The catalyst can condense into the coating or adsorb onto the surface to promote the curing reaction.

[0098] In another embodiment, the metal alkoxide and organic compound can be vaporized, condensed on the substrate, and cured. In one embodiment, curing can include contacting the layer with water. Curing may involve reacting the alkoxide with water to cure the film or increase its viscosity, accompanied by the (co)polymerization of the organic compound to form a mixed layer. Curing can also be performed in sequential steps. The components of the layer may be pre-reacted prior to deposition to form volatile oligomers. Curing may also involve reacting the components of the layer (alkoxide and organic compound) together in the presence or absence of water to form an organometallic (co)polymer. The layer having this organometallic (co)polymer can be designed to exhibit barrier properties that cannot be obtained if prepared by separate deposition and curing of the two components.

[0099] Anti-reflective layer

[0100] The retroreflective article disclosed herein includes an antireflective layer. The antireflective layer has a first primary surface and an opposing second primary surface. The second primary surface of the antireflective layer is attached to the structured surface of the retroreflective layer of the retroreflective article.

[0101] The antireflective layer may optionally comprise a porous gradient layer or a quarter-wavelength antireflective layer. The antireflective layer may optionally comprise a structured antireflective layer having a structured first master surface. The structured first master surface has a microstructure. The structured antireflective layer comprises a matrix and a nanoscale dispersed phase. The structured first master surface has a microstructured surface with randomly nanostructured anisotropic surfaces. The structured first master surface of the antireflective layer includes a skip-tooth pattern of the structure. In an exemplary embodiment, the skip-tooth pattern of the microstructure further includes nanostructures. In some embodiments, the antireflective layer further includes a fluoropolymer material.

[0102] Suitable fluoropolymers for antireflective layers include homopolymers (such as polyvinylidene fluoride) and copolymers (such as copolymers derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (e.g., available from 3M Company under the trade name 3M DYNEONTHV)); copolymers of TFE, HFP, vinylidene fluoride, and perfluoropropyl vinyl ether (PPVE) (e.g., available from 3M Company under the trade name 3M DYNEON THVP); polyvinylidene fluoride (PVDF) (e.g., available from 3M Company under the trade name 3M DYNEON PVDF 6008); ethylene-trifluorochloroethylene polymer (ECTFE) (e.g., available from Solvay, Brussels, Belgium under the trade name HALAR 350LC ECTFE); and ethylene-tetrafluoroethylene copolymer (ETFE) (e.g., available from 3M Company under the trade name 3M DYNEON ETFE 6235). (Company)); perfluoroalkoxyalkylene polymers (PFA); fluorinated ethylene propylene copolymers (FEP); polytetrafluoroethylene (PTFE); copolymers of TFE, HFP, and ethylene (HTE) (e.g., 3M DYNEON HTE1705, available from 3M Company). Combinations of fluoropolymers may also be used. In some embodiments, the fluoropolymer includes FEP. In some embodiments, the fluoropolymer includes PFA.

[0103] In some embodiments, the antireflective layer comprises a porous gradient layer or a quarter-wavelength antireflective layer. This antireflective layer or dielectric reflective layer comprises a quarter-wavelength antireflective layer whose thickness (d, in nm) and the product of its refractive index (n) (n»d) are equal to one-quarter of the wavelength of the reflected light. For example, to effectively increase light reflectivity in the 800 nm to 1200 nm wavelength range, the product (n»d) of the quarter-wavelength layer is designed to be in the range of 200 nm to 300 nm. Such a design effectively increases the reflectivity of light within the desired wavelength range (the reflected wavelength range) while increasing the transmittance of light in wavelength ranges outside the reflected wavelength range. In one example, visible light up to 800 nm can be reflected while infrared light exceeding 1200 nm can be transmitted, and vice versa. Such dielectric reflective layers can be formed by known methods, such as (a) forming a dielectric layer by multilayer coating on a transparent polymer film, and (b) forming a multilayer film by co-extrusion using a dielectric as the polymer material.

[0104] Materials other than polymers can also preferably be used as the dielectric reflective layer. Exemplary non-polymer materials include lithium fluoride (LiF), magnesium fluoride (MgF2), calcium fluoride (CaF2), barium fluoride (BaF2), lanthanum fluoride (LaF3), silicon dioxide (SiO2), aluminum dioxide (Al2O3), titanium dioxide (TiO2), silicon nitride, sodium chloride (NaCl), potassium chloride (KCl), potassium bromide (KBr), zinc sulfide (ZnS), zirconium oxide (ZrO2), and zinc selenide (ZnSe). When using non-polymer materials, the dielectric reflective layer can be bonded using physical or chemical deposition techniques, such as vacuum evaporation, sputtering, and chemical vapor deposition (CVD), depending on the type of dielectric reflective layer required.

[0105] In some embodiments, the antireflective layer is preferably provided in the form of a self-supporting film, i.e., a film with sufficient mechanical integrity that it can be easily handled without additional reinforcing layers. This antireflective property can be tailored to cover a selected range of electromagnetic frequencies, including portions of the visible, infrared (IR), and ultraviolet (UV) regions of the electromagnetic spectrum.

[0106] The anti-reflective (AR) layer can be used alone (forming an interface between the film and air) or optically coupled to one or both main surfaces of the substrate; in the latter case, the anti-reflective layer de-reflects radiation impacting the substrate surface at the substrate / AR construction interface. This anti-reflective layer can adhere to the surface of the substrate. However, preferably, it is formed simultaneously with the substrate via co-extrusion, as described in more detail below. Furthermore, the substrate / anti-reflective article itself can also be optically coupled, for example, by means of an adhesive, to another surface, such as a window.

[0107] The antireflective layer can consist of any number of polymer layers, typically ranging from one to dozens. The antireflective polymer layers can be optically thin, for example, with a thickness between about 0.010 μm and about 0.25 μm; or optically thick, for example, with a thickness greater than about 0.25 μm; or a combination of optically thin and optically thick layers. The specific thickness value is selected based on the electromagnetic spectrum portion to which the film is designed to operate, and in the case where the antireflective layer is optically coupled to the substrate, it is also selected based on the optical properties of the substrate. Preferably, the antireflective polymer layers are made of a polymer composition that can be co-extruded from each other, and in the case where the antireflective layer is optically coupled to the substrate, it is made of the material forming the substrate.

[0108] The antireflective polymer layer (which may be optically thick or thin) can be made of a thermoplastic polymer with a refractive index lower than that of the substrate. Specifically, reflection is minimized when the refractive index of the antireflective layer is approximately the square root of the multiple of the refractive index of the substrate and the surrounding medium (e.g., air), and the thickness is a quarter wavelength. Preferred polymers for the antireflective layer typically have a refractive index of less than about 1.45, more preferably less than about 1.38.

[0109] Low-refractive-index polymers suitable for antireflective layers include silicone polymers, methacrylate polymers, fluoropolymers, polyester copolymers, and chlorofluoropolymers. Fluoropolymers, such as THV-500, are particularly preferred. ™ Fluoropolymers (Dyneon LLC, St. Paul, Minnesota) are terpolymers of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene with a refractive index of 1.36, presented as a quarter-wavelength layer on a substrate. These polymers can reduce the total surface reflectance of a substrate with a relatively high refractive index by approximately two times, regardless of layer thickness. As a specific example, biaxially oriented polyethylene terephthalate (PET) has a refractive index of 1.66 at a normal incident angle and a reflectance of 6.0% for visible light on each surface. Using optically thick THV-500... ™ Covering this biaxially oriented PET substrate with a fluoropolymer layer will reduce the reflectivity of the composite film to a calculated value of approximately 3.26% per side. If the THV layer has a quarter-wavelength thickness, the reflectivity will be reduced even further.

[0110] To further reduce reflectivity, a multilayer antireflective (AR) structure of thin films may be preferred. Compared to a single-layer AR structure, such a structure offers the advantage of improved reflectivity reduction over a wide wavelength range while maintaining acceptable bandwidth. Each layer of the AR stack can typically be optically thin, although optically thick layers, or a combination of optically thin and optically thick layers, can also be used.

[0111] AR stacks can consist of any number of material layers, depending on the optical properties of the substrate and the desired portion of the electromagnetic spectrum to which the AR stack is designed to operate. Stacks with two or more layers can produce lower reflectivity over a wider wavelength band than a single layer, especially if the substrate's refractive index is below about 1.60. Due to the multiple layers in an AR stack, reflections from multiple interfaces can undergo destructive interference, thus reducing the overall reflectivity.

[0112] One of the materials in a multilayer AR stack preferably has a refractive index equal to or higher than the highest refractive index associated with the substrate. Since multilayer stacks consisting of only two materials can be designed to function as equivalent monolayers with virtually any refractive index, AR stacks with four or more layers can be manufactured using only two materials and have a wider bandwidth than three-layer stacks of three materials. This is useful for articles prepared by co-extrusion (as described below), because in the co-extrusion process, it is easier to add an additional layer of existing material than to add a new material. Suitable materials for AR layers include thermoplastic polymers, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, 2,6-polybutylene naphthalate, polyamides, polycarbonates, random polystyrene, syndiotactic polystyrene, and polymethyl methacrylate. Copolymers based on these materials may also be suitable.

[0113] Layers with different refractive indices can be separated by an "adhesive layer" with a refractive index between the surrounding layers. Such layers are particularly useful for improving adhesion between layers in a stack. An example of this configuration, in descending order of refractive index, is characterized by: polycarbonate / polymethyl methacrylate / polyvinylidene fluoride / THV fluoropolymer, wherein polymethyl methacrylate and polyvinylidene fluoride act as adhesive layers to improve adhesion between the polycarbonate and the THV fluoropolymer.

[0114] Particularly preferred articles include those in which one or more AR layers in an AR stack have the same material as the substrate or one or more layers of the substrate. For example, if the multilayer substrate film is to be dereflected in a portion of the wavelength spectrum (e.g., in the case where the substrate is an IR mirror and has an AR structure designed to dereflect visible light), it is desirable to design the AR stack with the same material as the mirror itself.

[0115] Another example of a useful article is an article characterized by a multilayer AR structure that combines a polymer layer and a layer of inorganic material with a higher refractive index.

[0116] In one embodiment, an inorganic material with a refractive index between that of the substrate and the organic polymer can be used. For example, the inorganic material can be a sol-gel deposited alumina layer or a zirconium oxide-silica mixture layer on a PEN (polyethylene naphthalate) substrate, and the organic polymer can be a fluoropolymer, such as THV-500. ™ .

[0117] In another embodiment, an inorganic material with a refractive index higher than that of the substrate can be used. For example, the inorganic material could be a sol-gel deposited zirconium oxide or titanium dioxide layer on a PEN substrate, and the organic polymer could be a quarter-wavelength thick fluoropolymer, such as THV-500.™ .

[0118] In another embodiment, the inorganic material may be silver, aluminum, or a quarter-wavelength-thick transparent conductor (such as indium tin oxide (ITO)) layer with far-infrared blocking capabilities, and the polymer layer may be a quarter-wavelength-thick fluoropolymer, such as THV-500. ™ .

[0119] In yet another implementation, inorganic materials can be combined with multilayer polymer structures.

[0120] Materials that can be used as substrates include organic polymers and inorganic materials with relatively high refractive indices (such as ceramics and glass). Particularly preferred substrate materials are monolayer and multilayer polymer films. Examples of suitable monolayer polymer films include polyethylene terephthalate films and polycarbonate films; in turn, such films can be uniaxially or biaxially oriented. One example of a suitable multilayer polymer film is a film in which the thickness of each polymer layer is no greater than about 0.5 micrometers, as described in U.S. Patent No. 5,278,694 (Wheatley et al.). A second example of a suitable multilayer polymer film is described in U.S. Patent No. 5,882,774 (Jonza et al.), which details multilayer polymer films (mirrors and polarizers) for which the Brewster angle (the angle at which reflectivity drops to zero) at the polymer layer interfaces is very large or nonexistent. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p-polarized light decreases slowly with the angle of incidence, is independent of the angle of incidence, or increases with increasing angles of incidence deviating from the normal. Therefore, multilayer films with high reflectivity for both s-polarized and p-polarized light can be achieved in both broadband and wide-angle ranges.

[0121] The relationship between the refractive indices of each layer in a substrate determines the substrate's reflection behavior at any angle of incidence from any azimuth. The principles and design considerations described in U.S. Patent No. 5,882,774 (Jonza et al.) can be applied to create multilayer substrates with desired optical effects in a variety of situations and applications. The refractive indices of each layer in this multilayer substrate can be manipulated and adjusted to produce devices with desired optical properties. Using the principles described therein, many useful devices can be designed and fabricated, such as mirrors and polarizers with various performance characteristics.

[0122] In the case of a polarizer, particularly preferred layer combinations include polyethylene naphthalate (“PEN”) / coPEN, polyethylene terephthalate (“PET”) / coPEN, PEN / syndiotactic polystyrene (“SPS”), PET / SPS, PEN / Estar, and PET / Estar, wherein “coPEN” refers to a copolymer or blend based on naphthalic acid, and “Estar” is a copolymer of terephthalic acid, ethylene glycol, and cyclohexane-1,4-diethanol, which is commercially available from Eastman Chemical Co.

[0123] In the case of a reflector, particularly preferred layer combinations include PET / Ecdel, PEN / Ecdel, PEN / SPS, PEN / THV, PEN / polymethyl methacrylate (“PMMA”), PEN / coPET, and PET / SPS, wherein “coPET” refers to a copolymer or blend based on terephthalic acid (as described above), “Ecdel” is a copolymer of cyclohexanedicarboxylic acid, ethylene glycol, and cyclohexane-1,4-diethanol, which is commercially available from Eastman Chemical Company, and “THV” is a fluoropolymer commercially available from 3M Company.

[0124] For reasons of film thickness, flexibility, and economy, the number of layers in the substrate is chosen to achieve the desired optical properties using the minimum number of layers. In the case of both polarizers and mirrors, the number of layers is preferably less than about 10,000, more preferably less than about 1,000.

[0125] When designing AR constructs for non-alien angles of incidence using birefringent polymers (such as oriented or partially crystalline polymers), further criteria must be considered. In these cases, it is necessary to account for the anisotropy of the refractive index. In other words, for non-alien angles, reflection will depend on both the refractive index perpendicular to the film plane and the in-plane refractive index, which applies to both the substrate and the AR construct. If the two in-plane refractive indices are different (biaxial birefringence), these differences must be considered for all angles of incidence.

[0126] In some embodiments, the antireflective layer comprises a porous gradient layer. The antireflective layer may comprise needle-like silica particles as described in U.S. Patent Application No. 12 / 187,977 (Jing et al.), and the term "porous" refers to the presence of voids between the needle-like silica particles when the particles form a continuous coating. For a single-layer antireflective coating, it is known that to maximize light transmission through an optically transparent substrate in air and minimize reflection from the substrate, the refractive index of the coating should be as close as possible to the square root of the substrate's refractive index, and the thickness of the coating should be one-quarter (¼) of the incident optical wavelength. The voids in the layer provide a large number of subwavelength gaps between the needle-like silica particles, where the refractive index (RI) abruptly changes from the refractive index of air (RI=1) to the refractive index of the metal oxide particles (e.g., for silica, RI=1.44). By adjusting the porosity, coatings with a calculated refractive index very close to the square root of the substrate's refractive index (as shown in U.S. Patent No. 4,816,333 (Lange et al., which is incorporated herein by reference) can be created. By utilizing a coating with an optimal refractive index and a thickness equal to approximately one-quarter of the optical wavelength of the incident light, the transmittance of light passing through the coated substrate is maximized and reflection is minimized. Preferably, the layer has a porosity of about 25 vol% to 65 vol% when dry, more preferably about 30 vol% to 50 vol%.

[0127] In some embodiments, the porosity can be even higher. The porosity can be calculated from the refractive index of the coating according to a procedure published in, for example, WLBragg, AB Pippard, Acta Crystallographica, volume 6, page 865 (1953), which is incorporated herein by reference. Using needle-like silica particles, this porosity results in a coating with a refractive index of 1.15 to 1.40, preferably 1.20 to 1.36, which is approximately equal to the square root of the refractive index of the polyester, polycarbonate, or poly(methyl methacrylate) substrate. For example, a porous needle-like silica particle coating with a refractive index of 1.25 to 1.36, when applied at a thickness of 1000 Å to 2000 Å on a polyethylene terephthalate substrate (RI = 1.64), can provide a highly anti-reflective surface. Coating thickness can be increased, up to several micrometers or mils thick, depending on the application, such as for easy cleaning or removal of unwanted particles, rather than for anti-reflective purposes. Improved mechanical properties are expected as coating thickness increases.

[0128] A transparent conductive film can be used as the antireflective layer. This film typically reflects light with wavelengths longer than a specific wavelength (this may be referred to as plasma reflection). An exemplary transparent conductive film is a thin film of a metal compound or combination of compounds, such as, for example, tin oxide, zinc oxide, and indium tin oxide (ITO). These layers receive light, reflect light in a predetermined proportion within the reflected wavelength range, and transmit light in a predetermined proportion within the transmitted wavelength range outside the reflected wavelength range. The reflectivity of light in the reflected wavelength range is preferably at least 40%, more preferably at least 50%, and most preferably at least 60%. The transmittance of light in the transmitted wavelength range is preferably at least 40%, more preferably at least 50%.

[0129] In some embodiments, the transparent conductive film is a low-emissivity film. In another embodiment, the film comprises: a) a first layer comprising zirconium nitride; b) a metal layer adjacent to the first layer comprising zirconium nitride; c) a substrate layer for the metal layer, the substrate layer comprising a compound selected from zirconium nitride, aluminum zinc oxide (AZO), zinc tin oxide, tin oxide, and zinc oxide, wherein the substrate layer for the metal layer is adjacent to the metal layer; and d) a substrate adjacent to the substrate layer for the metal layer; wherein the film has an emissivity of less than 0.2, a visible light reflectance of less than 25%, and a visible light transmittance of greater than 50%. In some embodiments, the substrate layer for the metal layer is a second layer comprising zirconium nitride.

[0130] In some embodiments, the membrane further includes a first radiation-cured acrylate layer adjacent to the first radiation-cured acrylate layer. In other embodiments, the membrane further includes a first layer comprising a silicon compound adjacent to the first radiation-cured acrylate layer, wherein the silicon compound is selected from silicon aluminum oxide, silicon aluminum oxynitride; silicon oxide, silicon oxynitride, silicon nitride, silicon aluminum nitride, and combinations thereof. In some embodiments, the first layer comprising the silicon compound is the outermost layer of the membrane.

[0131] In other embodiments, the film further includes a dielectric layer adjacent to a substrate layer for a metal layer. In some embodiments, the dielectric layer is a second layer comprising a silicon compound, wherein the silicon compound is selected from silicon aluminum oxide, silicon aluminum oxynitride; silicon oxide, silicon oxynitride, silicon nitride, silicon aluminum nitride, and combinations thereof.

[0132] In other embodiments, the film further includes a second radiation-cured acrylate layer adjacent to a second layer comprising a silicon compound and also adjacent to the substrate.

[0133] In other embodiments, the membrane further includes a layer comprising a pressure-sensitive adhesive adjacent to the substrate, and also includes a release film adjacent to the layer comprising the pressure-sensitive adhesive.

[0134] In other embodiments, the film comprises, in the order listed, the following layers: a first layer comprising a silicon compound, wherein the silicon compound is selected from silicon aluminum oxide and silicon aluminum oxynitride; silicon oxide, silicon oxynitride, silicon nitride, silicon aluminum nitride, and combinations thereof; a first radiation-cured acrylate layer; a first layer comprising zirconium nitride, wherein the layer has a thickness of 1 nm to 615 nm; a metal layer, a second layer comprising zirconium nitride, wherein the layer has a thickness of 1 nm to 615 nm; a second layer comprising a silicon compound, wherein the silicon compound is selected from silicon aluminum oxide and silicon aluminum oxynitride, silicon oxide, silicon oxynitride, silicon aluminum nitride, and combinations thereof; a second radiation-cured acrylate layer; and a substrate, wherein the film has an emissivity of less than 0.2, wherein the film has a visible light reflectance of less than 25%, and wherein the film has a visible light transmittance of greater than 50%. The properties of the different layers that can be part of the film, as described in U.S. Patent No. 10,723,102 (Padiyath et al.), can be used.

[0135] In some embodiments, the antireflective layer comprises a matrix and a nanoscale dispersed phase. Polymer materials used for the matrix include thermoplastic and thermosetting resins. Suitable thermoplastics include (but are not limited to): polyethylene terephthalate (PET), polystyrene, acrylonitrile-butadiene-styrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyacrylate, thermoplastic polyurethane, polyvinyl acetate, polyamide, polyimide, polypropylene, polyester, polyethylene, poly(methyl methacrylate), polyethylene naphthalate, styrene-acrylonitrile, silicone-polydiacetamide polymers, fluoropolymers, cyclic olefin copolymers, thermoplastic elastomers, etc.

[0136] Suitable thermosetting resins include, but are not limited to, allyl resins (including (meth)acrylates, polyester acrylates, urethane acrylates, epoxy acrylates, and polyether acrylates), epoxy resins, thermosetting polyurethanes, silicones, or polysiloxanes. These resins can be formed from the reaction products of polymerizable compositions comprising the respective monomers and / or oligomers.

[0137] In one embodiment, the polymerizable composition comprises at least one monomer or oligomeric (meth)acrylate, preferably a urethane (meth)acrylate. Typically, the monomer or oligomeric (meth)acrylate is a poly(meth)acrylate. The term "(meth)acrylate" is used to refer to an ester of acrylic acid and methacrylic acid, and in contrast to "poly(meth)acrylate," which typically refers to a polymer of (meth)acrylates, "poly(meth)acrylate" refers to a molecule containing more than one (meth)acrylate group. Most commonly, the poly(meth)acrylate is a di(meth)acrylate, but tri(meth)acrylate, tetra(meth)acrylate, etc., are also conceivable.

[0138] Suitable monomers or oligomeric (meth)acrylates include alkyl (meth)acrylates, such as methyl (meth)acrylate, ethyl (meth)acrylate, 1-propyl (meth)acrylate, and tert-butyl (meth)acrylate. Acrylates may include (fluoro)alkyl (meth)acrylate monomers that are partially and / or fully fluorinated, such as trifluoroethyl (meth)acrylate.

[0139] Examples of commercially available poly(meth)acrylate resins include the DIABEAM series from Mitsubishi Rayon Co., LTD.; the DINACOL series from Nagase & Company, Ltd.; the NK ESTER series from Shin-Nakamura Chemical Co., Ltd.; the UNIDIC series from Dainippon Ink & Chemicals, Inc.; the ARONIX series from Toagosei Co., LTD.; the BLENMER series manufactured by NOF Corp.; the KAYARAD series from Nippon Kayaku Co., Ltd.; and the LIGHT ESTER and LIGHTACRYLATE series from Kyoeisha Chemical Co., Ltd.

[0140] Oligomeric urethane poly(meth)acrylates are available from Sartamomer under the trade names “Photomer 6000 series” (such as “Photomer 6010” and “Photomer 6020”) and “CN 900 series” (such as “CN966B85”, “CN964”, and “CN972”). Oligomeric urethane (meth)acrylates are also available from surface specialties, for example, under the trade names “Ebecryl 8402”, “Ebecryl 8807”, and “Ebecryl 4827”. Oligomeric urethane (meth)acrylates can also be prepared by the initial reaction of an alkylene or aromatic diisocyanate of the general formula OCN-R3-NCO with a polyol. Most commonly, the polyol is a diol of the general formula HO-R4-OH, where R3 is a C2-100 alkylene or arylene and R4 is a C2-C... 100Alkylene. The intermediate product is then a polyurethane diol diisocyanate, which can subsequently react with a hydroxyalkyl (meth)acrylate. Suitable diisocyanates include 2,2,4-trimethylhexylene diisocyanate and toluene diisocyanate. Alkylene diisocyanates are generally preferred. Particularly preferred compounds of this type can be prepared from 2,2,4-trimethylhexylene diisocyanate, poly(caprolactone) glycol, and 2-hydroxyethyl methacrylate. In at least some cases, the urethane (meth)acrylate is preferably aliphatic.

[0141] The polymerizable constituent material can be a mixture of monomers and / or oligomers having the same or different reactive functional groups. Polymerizable constituent materials containing two or more different functional groups can be used, including (meth)acrylates, epoxides, and urethanes. Different functional groups can be contained in different monomers and / or oligomer moieties, or in the same monomer and / or oligomer moieties. For example, the resin constituent material can contain acrylic resins or urethane resins having epoxy and / or hydroxyl groups in the side chain, compounds having amino groups, and optionally silane compounds having epoxy or amino groups in the molecule.

[0142] Thermosetting resin compositions can be polymerized using conventional techniques such as thermosetting, photocuring (curing by photochemical radiation), and / or electron beam curing. In one embodiment, the resin is photopolymerized by exposing it to ultraviolet (UV) and / or visible light. Conventional curing agents and / or catalysts can be used in polymerizable compositions and are selected based on the functional groups in the composition. If multiple curing functional groups are used, multiple curing agents and / or catalysts may be required. Combining one or more curing techniques (such as thermosetting, photocuring, and electron beam curing) is within the scope of this invention.

[0143] Furthermore, the polymerizable resin may be a composition comprising at least one other monomer and / or oligomer (that is, in addition to those monomers and / or oligomers as described above, i.e., monomeric or oligomeric (meth)acrylates and oligomeric urethane (meth)acrylates). Other monomers may reduce viscosity and / or improve thermomechanical properties and / or increase refractive index. Monomers possessing these properties include acrylic monomers (i.e., acrylates and methacrylates, acrylamides and methacrylamides), styrene monomers, and olefinically unsaturated nitrogen heterocyclic compounds.

[0144] This also includes (meth)acrylates with other functional groups. Examples of such compounds include 2-(N-butylcarbamoyl)ethyl (meth)acrylate, 2,4-dichlorophenylacrylate, 2,4,6-tribromophenylacrylate, tribromophenoxyethyl acrylate, tert-butylphenyl acrylate, phenyl acrylate, phenyl thioethyl acrylate, alkoxylated phenyl acrylate, isobornyl acrylate, and phenoxyethyl acrylate. The reaction product of tetrabromobisphenol A diepoxide and (meth)acrylic acid is also suitable.

[0145] Other monomers may also be N-substituted or N,N-disubstituted (meth)acrylamides, particularly acrylamides. These monomers include N-alkylacrylamides and N,N-dialkylacrylamides, especially those containing C1-4 alkyl groups. Examples include N-isopropylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide.

[0146] Other monomers may also be polyol poly(meth)acrylates. These compounds are typically prepared from aliphatic diols, triols, and / or tetraols containing 2 to 10 carbon atoms. Examples of suitable poly(meth)acrylates are ethylene glycol diacrylate, 1,6-hexanediol diacrylate, 2-ethyl-2-hydroxymethyl-1,3-propanediol triacrylate (trimethylolpropane triacrylate), di(trimethylolpropane)tetraacrylate, pentaerythritol tetraacrylate, and corresponding methacrylates and (meth)acrylates of alkoxylated (typically ethoxylated) derivatives of said polyols. Monomers having two or more olefinically unsaturated groups can be used as crosslinking agents.

[0147] Styrene compounds suitable for use as other monomers include styrene, dichlorostyrene, 2,4,6-trichlorostyrene, 2,4,6-tribromostyrene, 4-methylstyrene, and 4-phenoxystyrene. Alkene-unsaturated nitrogen heterocyclic compounds include N-vinylpyrrolidone and vinylpyridine.

[0148] The composition ratio in radiation-curable materials can vary. Generally, the organic component may include about 30%-100% monomers and / or oligomeric (meth)acrylates or oligomeric urethane poly(meth)acrylates, with the remainder being other monomers and / or oligomers.

[0149] Commercially available liquid resin-based materials (often referred to as "hard coatings") can be used as a matrix or as a component of a matrix. Such materials include the PERMANEW series from California Hardcoating Co., San Diego, California, and the UVHC series of hard coatings from Momentive Performance Materials, Albany, NY. Additionally, commercially available nanoparticles can be used to fill the matrix, such as NANOCRYL and NANOPDX from Nanoresins AG, Geesthacht Germany.

[0150] Nanoscale dispersed phases are discontinuous phases randomly dispersed within a matrix. Nanoscale dispersed phases may include nanoparticles (e.g., nanospheres), nanotubes, nanofibers, cage-like molecules, hyperbranched molecules, micelles, anti-micelles, etc. Preferably, the dispersed phase comprises nanoparticles or cage-like molecules; more preferably, the dispersed phase comprises nanoparticles.

[0151] The nanoparticles preferably have an average diameter in the range of about 1 nm to about 100 nm. Preferably, the nanoparticles have an average diameter of 5 nm, 20 nm, or 80 nm. The nanoparticles used as the dispersed phase may comprise metals, metal oxides, carbides, nitrides, borides, halides, fluorocarbon solids, etc., or mixtures thereof. Preferred materials include SiO2, ZrO2, TiO2, ZnO, calcium carbonate, magnesium silicate, indium tin oxide, antimony tin oxide, carbon, poly(tetrafluoroethylene), etc. Preferably, the nanoparticles comprise SiO2.

[0152] The nanoparticles may be present in the matrix of the antireflective layer in an amount of about 1% to about 60% by weight, or about 10% to about 40%. Silica used in the materials disclosed herein is commercially available from Nalco Chemical Co., Naperville, Ill. under the trade name “Nalco Colloidal Silicas,” such as products 1040, 1042, 1050, 1060, 2327, and 2329. Suitable fumed silica includes, for example, products commercially available from Evonik under the trade name “Aerosil series OX-50” and product numbers -130, -150, and -200. Other colloidal silica is also available from Nissan Chemicals under the names “IPA-ST,” “IPA-ST-L,” and “IPA-ST-ML.” Fumed silica is also commercially available from Cabot Corp., Tuscola, Illinois, under the names “CAB-O-SPERSE 2095”, “CAB-O-SPERSE A105”, and “CAB-O-SIL M5”. Zirconia used in the compositions and articles of this invention is available from Nalco Chemical Co. under the trade name “Nalco OOSSOO8”.

[0153] Surface treatment of nanoparticles can provide a stable dispersion in polymerizable resins. Preferably, the surface treatment stabilizes the nanoparticles, allowing them to be well dispersed in the polymerizable resin and producing a substantially homogeneous composition. Furthermore, at least a portion of the surface of the nanoparticles can be modified with a surface treatment agent so that the stabilized particles can copolymerize or react with the polymerizable resin during curing.

[0154] The nanoparticles are preferably treated with a surface treatment agent. Generally, the surface treatment agent has a first end group and a second end group. The first end group attaches to the particle surface (through covalent bonds, ionic bonds, or strong physisorption), and the second end group imparts compatibility with the resin and / or allows the particles to react with the resin during curing. Examples of surface treatment agents include alcohols, amines, carboxylic acids, sulfonic acids, phosphonic acids, silanes, and titanates. The preferred type of treatment agent is determined in part by the chemical properties of the metal oxide surface. Silanes are preferred for silica and other silicon-containing fillers. Silanes and carboxylic acids are preferred for metal oxides such as zirconium oxide. Surface modification can be performed after mixing with the monomer or after mixing. With regard to silanes, it is preferable to react the silane with the particles or the nanoparticle surface before incorporating the silane into the resin. The required amount of surface modifier depends on several factors, such as particle size, particle type, molecular weight of the modifier, and type of modifier.

[0155] Representative embodiments of surface treatment agents include isooctyltri-methoxy-silane, N-(3-triethoxysilylpropyl)methoxyethoxy-ethoxyethyl ester (PEG3TES), N-(3-triethoxysilylpropyl)methoxyethoxyethoxyethyl ester (PEG2TES), 3-(methacryloyloxy)propyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-(methacryloyloxy)propyltriethoxysilane, 3-(methacryloyloxy)propylmethyldimethoxysilane, 3-(acryloyloxypropyl)methyldimethoxysilane, 3-(methacryloyloxy)propyldimethylethoxysilane, vinyldimethylethoxysilane, phenyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, and octadecyltrimethoxysilane. Compounds such as propyltrimethoxysilane, hexyltrimethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltritert-butoxysilane, vinyltriisobutoxysilane, vinyltriisopropoxysilane, vinyltri(2-methoxyethoxy)silane, styrylethyltrimethoxysilane, mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, acrylic acid, methacrylic acid, oleic acid, stearic acid, dodecanoic acid, 2-(2-(2-methoxyethoxy)ethoxy)acetic acid (MEEAA), β-carboxyethyl acrylate, 2-(2-methoxyethoxy)acetic acid, methoxyphenylacetic acid, and mixtures thereof. Alternatively, a proprietary silane surface modifier, available under the trade name "Silquest A1230" from OSI Specialties (Crompton South Charleston, WV), is also suitable.

[0156] Surface modification of particles in colloidal dispersions can be achieved by various methods. The process involves mixing an inorganic dispersion with a surface modifier. Optionally, a co-solvent, such as 1-methoxy-2-propanol, ethanol, isopropanol, ethylene glycol, N,N-dimethylacetamide, and 1-methyl-2-pyrrolidone, can be added at this stage. This co-solvent enhances the solubility of both the surface modifier and the surface-modified particles. The mixture containing the inorganic sol and the surface modifier is then reacted at room temperature or high temperature, mixed or unmixed. In one method, the mixture may be reacted at about 85°C for about 24 hours to obtain a surface-modified sol. In another method for surface modification of metal oxides, the surface treatment of the metal oxides may preferably involve adsorbing acidic molecules onto the particle surface. Surface modification of heavy metal oxides is preferably carried out at room temperature.

[0157] Surface modification of ZrO2 with silanes can be carried out under acidic or alkaline conditions. In one case, the silane is heated for a suitable period of time under acidic conditions, during which the dispersion is combined with ammonia (or other alkali). This method allows for the removal of acidic counterions from the ZrO2 surface and their reaction with the silane. In another method, the particles are precipitated from the dispersion and separated from the liquid phase.

[0158] Combinations of surface modifiers can be useful, wherein at least one of the modifiers has a functional group that copolymerizes with a groupable resin. For example, the polymerizable group can be an olefinically unsaturated functional group or a cyclic functional group that readily undergoes ring-opening polymerization. The olefinically unsaturated polymerizable group can be, for example, an acrylate or (meth)acrylate or a vinyl group. Cyclic functional groups that readily undergo ring-opening polymerization generally contain heteroatoms such as oxygen, sulfur, or nitrogen, preferably a three-membered ring containing oxygen, such as an epoxide.

[0159] Available cage-like molecules for nanoscale dispersions include faceted oligomeric silsesquioxane molecules, which are cage-like hybrid molecules of siloxane and oxygen. Faceted oligomeric silsesquioxane (POSS) molecules are derived from compounds of a continuously evolving class closely related to siloxanes through composition and a shared nomenclature system. POSS molecules have two unique characteristics: (1) their chemical composition is a hybrid intermediate (RSiO) between silicon dioxide (SiO2) and organosilicon (R2SiO). 1.5(1) and (2) these molecules are physically large relative to polymer size and are almost equivalent in size to most polymer chain segments and coils. Therefore, POSS molecules can be considered as the smallest possible particles of silica (about 1-1.5 nm). However, unlike silica or modified clay, each POSS molecule contains covalently bonded reactive functional groups suitable for polymerization or grafting POSS monomers onto polymer chains. In addition, POSS acrylate and methacrylate monomers are suitable for ultraviolet (UV) curing. High-functionality POSS acrylates and methacrylates (e.g., MA0735 and MA0736) are miscible with most UV-curable acrylic and polyurethane acrylic monomers or oligomers to form mechanically durable hard coatings in which POSS molecules form a nanophase uniformly dispersed in an organic coating matrix.

[0160] Carbon can also be used in the form of graphite, carbon nanotubes, buckyballs, or carbon black in nanoscale dispersed phases, as described in U.S. Patent No. 7,368,161 (McGurran et al.).

[0161] Other materials that can be used in nanoscale dispersed phases include Irgastat ™ P18 (available from Ciba Corporation, Tarrytown, NY) and Ampacet LR-92967 (available from Ampacet Corporation, Tarrytown, NY).

[0162] The dispersed phase is typically present in the matrix at a concentration between about 1% by weight and about 50% by weight; preferably between about 5% by weight and about 25% by weight.

[0163] In some embodiments, the structured surface of the antireflective layer of this disclosure has a microstructured surface with a randomly nanostructured anisotropic surface. The nanostructured anisotropic surface typically includes nanofeatures with an aspect ratio of about 2:1 or greater; preferably about 5:1 or greater. In some embodiments, the aspect ratio is even 50:1 or greater, 100:1 or greater, or 200:1 or greater. The nanostructured anisotropic surface may have nanofeatures, such as nanopillars or nanocylinders, or continuous nanowalls comprising nanopillars or nanocylinders. Preferably, the nanofeatures have steep sidewalls that are substantially perpendicular to the substrate. In some embodiments, most of the nanofeatures are capped by a dispersed phase material. The concentration of the dispersed phase at the surface (relative to that inside the matrix) can be between about 5 wt% and about 90 wt%; preferably between about 10 wt% and about 75 wt%. In some embodiments, the concentration of the dispersed phase at the matrix surface is higher than the concentration inside the matrix.

[0164] In some embodiments, the matrix may contain electrostatically dissipative materials to minimize the adsorption of dust and particulate matter, thereby maintaining surface quality. Suitable materials for electrostatic dissipation include, for example, Stat-Rite. ™ Polymers such as X-5091, M-809, S-5530, S-400, S-403, and S-680 (obtained from Lubrizol, Wickliffe, Ohio); 3,4-polyvinyldioxythiophene-polystyrene sulfonic acid (PEDOT / PSS) (obtained from HC Starck, Cincinnati, Ohio); polyaniline; polythiophene; Pelestat ™ Antistatic additives NC6321 and NC7530 (obtained from Tomen America Inc., New York, NY); antistatic compositions containing at least one ionic salt consisting of a nonpolymerized nitrogenium cation and a weakly coordinated fluorine organic anion, as disclosed in U.S. Patent No. 6,372,829 (Lamanna et al.) and as disclosed in U.S. Patent Application Publication No. 2007 / 0141329 A1.

[0165] Nanostructured surfaces are formed by anisotropic etching of a matrix. For example, a matrix comprising a nanoscale dispersed phase can be used as a coating on a substrate. The substrate can be, for example, a polymer substrate, a glass substrate or window, or a functional device such as an organic light-emitting diode (OLED), a display, a photovoltaic device, etc. The matrix containing the dispersed phase can be coated onto the substrate and cured using methods known in the art, such as casting curing by a casting roller, molding coating, flow coating, or dip coating. The coating can be formed at any desired thickness greater than about 1 micrometer, or preferably greater than about 4 micrometers. Alternatively, the coating can be cured by UV, electron beam, or heat. Or, the matrix comprising the dispersed phase can be an article of manufacture itself.

[0166] In some embodiments, the surface of a matrix comprising a nanoscale dispersed phase can be microstructured. For example, a substrate having a V-groove microstructured surface can be coated with a polymerizable matrix material comprising a nanoscale dispersed phase and subjected to plasma etching to form nanostructures on the V-groove microstructured surface. Alternatively, microstructured articles such as Fresnel lenses or microstructured articles comprising microreplicated pedestals or cylinders (comprising a nanoscale dispersed phase) can be plasma-etched to form nanostructures on the microstructure. Other examples include: finely microstructured surfaces obtained by controlled solvent evaporation in a multi-solvent coating solution, as described in U.S. Patent No. 7,378,136 (Pokorny et al.); or structured surfaces obtained by microreplication methods, as disclosed in U.S. Patent No. 7,604,381 (Hebrink et al.); or any other structured surfaces induced by electric and magnetic fields or other means.

[0167] Anisotropic etching of a substrate is performed using chemically reactive plasma. For example, the RIE (Reactive Ion Etching) process involves generating plasma in a vacuum using an electromagnetic field. High-energy ions from the plasma attack or etch away the substrate material, as described in U.S. Patent No. 9,939,557 (David et al.).

[0168] Microstructures on a matrix surface comprising a nanoscale dispersed phase can be arranged as a series of alternating micropeaks and microgap formations. The microstructures may comprise a series of alternating micropeaks and microgap formations along an axial direction, or in a line. The axial direction may correspond to the width dimension. Microgap formations may each be disposed between a pair of micropeaks. In other words, multiple micropeaks may be separated from each other by at least one microgap. In at least one embodiment, at least one pair of micropeaks may not include a microgap. The pattern of alternating micropeaks and microgap formations can be described as a “skip-tooth pattern” present on the structured first master surface of the antireflective layer. Each of the micropeaks and microgap formations may include at least one straight or curved segment. Each of the micropeaks and microgap formations may optionally include nanostructures on its surface.

[0169] method

[0170] In a second aspect, this disclosure provides a method for retaining light in a greenhouse. The method includes attaching a retroreflective article according to any embodiment of the first aspect described in detail above to at least one of a transparent roof, wall, or window of the greenhouse. The retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the greenhouse. In some embodiments, the method includes attaching the retroreflective article to the greenhouse using an adhesive. The adhesive includes a pressure-sensitive adhesive or a hot-melt adhesive. According to certain embodiments, the method includes suspending the retroreflective article on the transparent roof, wall, or window.

[0171] kit

[0172] In a third aspect, this disclosure provides a kit. The kit includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface opposite a main surface; and an antireflective layer having a first main surface and an opposite second main surface. The retroreflective layer is an antireflective layer according to any embodiment of the antireflective layer described in detail above with respect to the first aspect. Optionally, the kit also includes a pressure-sensitive adhesive or a hot-melt adhesive.

[0173] Figure 7 A schematic cross-sectional view of an exemplary embodiment of the kit in use is depicted, wherein a retroreflective layer is adhered to one side of a substrate via an adhesive layer, and an antireflective layer is adhered to the opposite side of the substrate via an optically clear adhesive. More specifically, the kit in use includes a retroreflective layer (710) and an antireflective layer (720) respectively attached to opposing main surfaces (772) and (774) of a substrate (770) (e.g., greenhouse glass, building window, etc.). The retroreflective layer (710) includes a plurality of surface structure elements that collectively form a structured surface (710b) opposite to the main surface (710a). The antireflective layer (720) includes a first main surface (720b) ​​and an opposing second main surface (720a). The second main surface (720a) of the antireflective layer (720) is attached to the second main surface (774) of the substrate (770) via an adhesive layer (750). The antireflective layer (720) includes a structured antireflective layer having a structured first main surface (730). In some cases, the structured first primary surface (730) includes microstructures. Such a structured first primary surface (730) may have a structured skip-tooth pattern (740) with micropeaks (740a) and microgap (740b). In some cases, the adhesive layer (750) is an optically transparent adhesive. The kit in use also includes another adhesive layer (760) that adheres the retroreflective layer (710) to the first primary surface (772) of the substrate (770). In some cases, the second adhesive layer (760) is in the form of multiple adhesive strips or dots.

[0174] The implementation plan selected in this public disclosure

[0175] Embodiment 1 is a retroreflective article. The retroreflective article includes a plurality of surface structural elements that collectively form a structured surface opposite to a main surface; and an antireflective layer having a first main surface and an opposite second main surface. The second main surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

[0176] Implementation scheme 2 is a retroreflective article according to implementation scheme 1, wherein the retroreflective article includes an adhesive layer. The adhesive layer is disposed between the retroreflective layer and the antireflective layer.

[0177] Implementation scheme 3 is a retroreflective article according to implementation scheme 1 or implementation scheme 2, wherein the retroreflective article includes an adhesive layer disposed between the retroreflective layer and the antireflective layer.

[0178] Implementation Scheme 4 is a retroreflective article according to Implementation Scheme 2 or Implementation Scheme 3, wherein the adhesive layer comprises polyethylene terephthalate (PET), crosslinked polysiloxane, silicone thermoplastic polymer, crosslinked polyurethane, thermoplastic polyurethane, crosslinked (meth)acrylate, polymethyl methacrylate (PMMA), copolymer of ethyl acrylate and methyl methacrylate (coPMMA), polyimide, cyclic olefin copolymer, cyclic olefin polymer, polycarbonate, polyisobutylene (PIB), polyvinyl butyrate, butyl rubber (BR), epoxy resin, thiol, thioolefin, or combinations thereof.

[0179] Embodiment 5 is a retroreflective article according to any one of Embodiments 2 to 4, wherein the adhesive layer comprises an optically transparent adhesive comprising at least one polyisobutylene resin and a polyfunctional (meth)acrylate monomer.

[0180] Embodiment 6 is a retroreflective article according to any one of Embodiments 2 to 5, wherein the adhesive layer further comprises at least one of the following: a first UV absorber or a first hindered amine light stabilizer (HALS).

[0181] Implementation scheme 7 is a retroreflective article according to any one of implementation schemes 1 to 6, wherein the retroreflective article includes a blocking layer.

[0182] Embodiment 8 is a retroreflective article according to any one of Embodiments 1 to 7, wherein the retroreflective article includes a barrier layer disposed between the retroreflective layer and the antireflective layer.

[0183] Implementation scheme 9 is a retroreflective article according to implementation scheme 7 or implementation scheme 8, wherein the blocking layer includes a metal oxide layer, which includes at least one of the following: titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, aluminum silicon oxide or niobium oxide.

[0184] Implementation scheme 10 is a retroreflective article according to implementation scheme 9, wherein the thickness of the metal oxide layer is 15 nanometers to 60 nanometers (nm).

[0185] Embodiment 11 is a retroreflective article according to any one of embodiments 7 to 10, wherein the blocking layer comprises: at least one paired layer, the at least one paired layer being composed of a (co)polymer layer and an inorganic layer covering the (co)polymer layer; and an outer (co)polymer layer covering the at least one paired layer; and optionally at least one outer inorganic layer covering the outer (co)polymer layer.

[0186] Embodiment 12 is a retroreflective article according to any one of Embodiment 11, wherein at least one paired layer is a plurality of paired layers. The plurality of paired layers is two paired layers, three paired layers, four paired layers, five paired layers, or six paired layers.

[0187] Implementation scheme 13 is a retroreflective article according to implementation scheme 11 or implementation scheme 12, wherein the inorganic layer is formed of an inorganic material selected from the following: silicon oxide, silicon aluminum oxide, silicon oxynitride, gallium oxide, magnesium oxide, niobium oxide, titanium dioxide, yttrium oxide, zinc oxide, tin oxide, nickel oxide, tungsten oxide, aluminum-doped zinc oxide, indium tin oxide, zirconium oxide, zirconium oxynitride, hafnium oxide, aluminum oxide, aluminum-doped silicon oxide, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or combinations thereof.

[0188] Embodiment 14 is a retroreflective article according to any one of Embodiments 11 to 13, wherein each of the at least one pair of layers comprises a (co)polymer selected from the group consisting of olefin (co)polymers, (meth)acrylate (co)polymers, urethane (co)polymers, silicone (co)polymers, or combinations thereof.

[0189] Embodiment 15 is a retroreflective article according to any one of Embodiments 11 to 14, wherein at least one (co)polymer layer further comprises at least one of the following: a first UV absorber or a first hindered amine light stabilizer (HALS).

[0190] Embodiment 16 is a retroreflective article according to any one of embodiments 1 to 15, wherein the retroreflective article includes an optically transparent adhesive attached to a first primary surface of the antireflective layer.

[0191] Embodiment 17 is a retroreflective article according to any one of embodiments 1 to 16, wherein the retroreflective article exhibits a refractive index difference of 1.49 or greater, 1.51, 1.53, 1.55, 1.57 or 1.59 or greater from one primary surface of the retroreflective article to the relative primary surface of the retroreflective article.

[0192] Embodiment 18 is a retroreflective article according to any one of embodiments 1 to 17, wherein the surface structural element includes at least one shape having a cross-section selected from the group consisting of ellipse, semicircle, oblong and polygon in a plane parallel to the opposing main surface of the retroreflective layer.

[0193] Implementation scheme 19 is a retroreflective article according to any one of implementation schemes 1 to 18, wherein the surface structural element comprises at least one shape selected from the group consisting of: a cubic corner, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cubic corner.

[0194] Embodiment 20 is a retroreflective article according to any one of Embodiments 1 to 19, wherein the antireflective layer comprises a porous gradient layer or a quarter-wavelength antireflective layer.

[0195] Implementation scheme 21 is a retroreflective article according to any one of implementation schemes 1 to 19, wherein the antireflective layer includes a structured antireflective layer having a structured first primary surface.

[0196] Implementation scheme 22 is a retroreflective article according to implementation scheme 21, wherein the structured first main surface includes microstructures.

[0197] Implementation scheme 23 is a retroreflective article according to implementation scheme 21 or implementation scheme 22, wherein the structured antireflective layer includes a matrix and a nanoscale dispersed phase, and the structured surface has a microstructured surface, which has a random nanostructured anisotropic surface.

[0198] Implementation scheme 24 is a retroreflective article according to any one of implementation schemes 21 to 23, wherein the structured first main surface includes a structured skip tooth pattern.

[0199] Implementation scheme 25 is a retroreflective article according to any one of implementation schemes 1 to 24, wherein the antireflective layer comprises a fluoropolymer material.

[0200] Embodiment 26 is a method for retaining light in a greenhouse. The method includes attaching a retroreflective article according to any one of embodiments 1 to 25 to at least one of the transparent roof, wall, or window of the greenhouse. The retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the greenhouse.

[0201] Embodiment 27 is a method for retaining light in a building having windows or skylights. The method includes attaching a retroreflective article according to any one of embodiments 1 to 25 to at least one of the windows or skylights of the building. The retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the building.

[0202] Implementation scheme 28 is the method according to implementation scheme 26 or implementation scheme 27, wherein the retroreflective article is attached via an adhesive.

[0203] Implementation scheme 29 is the method according to any one of implementation schemes 26 to 28, wherein the retroreflective article is suspended on a transparent roof, wall, window or skylight.

[0204] Implementation scheme 30 is a kit. The kit includes an antireflective layer comprising a plurality of surface structure elements that collectively form a structured surface opposite to a main surface; and an antireflective layer having a first main surface and an opposite second main surface.

[0205] Implementation scheme 31 is the kit according to implementation scheme 30, wherein the kit includes a pressure-sensitive adhesive or a hot melt adhesive.

[0206] Implementation scheme 32 is the kit according to implementation scheme 30 or implementation scheme 31, wherein a pressure-sensitive adhesive or hot melt adhesive is used to attach the surface structure of the retroreflective article to the interior of the greenhouse or building and to attach the antireflective layer to the exterior surface of the greenhouse or building.

[0207] The articles, kits, and methods disclosed herein have been frequently described with reference to their use in general agricultural applications, particularly in greenhouses. However, those skilled in the art will understand that these articles, kits, and methods can also be used in a variety of other applications, including, for example, general indoor applications.

[0208] Example

[0209] Comparative Example 1

[0210] The visible light transmittance of a smooth 6mm thick glass (available from Pilkington Glass, Toledo, OH, under the trade name OptiWhite Low Iron) was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD, MD) with both side 1 and side 2 of the glass facing the light source being 91.7%.

[0211] Comparative Example 2

[0212] As described in Predicted Example 1 of patent application WO2019 / 130198A1, an LDPE-STR nano-microstructured antireflective film was prepared using low-density polyethylene (available as DOW955i LDPE from Dow Corporation, Midland, MI). The visible light transmittance of this surface-structured antireflective film was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD) according to ASTM D1003 Method B, with 94.6% on side 1 facing the light source and 98.5% on side 2 facing the light source.

[0213] Comparative Example 3

[0214] As described in Predicted Example 1 of patent application WO2019 / 130198A1, a PVDF-STR nano-microstructured antireflective film was prepared using polyvinylidene fluoride (available as PVDF6008 from 3M Company, Maplewood, MN). The visible light transmittance of this surface-structured antireflective film was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MN) according to ASTM D1003 Method B, with 98.1% visible light transmittance on side 1 facing the light source and 96% visible light on side 2.

[0215] Comparative Example 4

[0216] As described in Predicted Example 1 of patent application WO2019 / 130198A1, an LDPE-STR nano-microstructured antireflective film was prepared using low-density polyethylene (available as DOW955i LDPE from Dow Corporation, Midland, Michigan). The smooth sides of the nano-microstructured antireflective film were laminated to the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M). The visible light transmittance of this antireflective film laminated to the glass was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD) according to ASTM D1003 Method B, with 82% for the surface-structured film side 1 facing the light source and 86% for the smooth glass side 2 facing the light source.

[0217] Comparative Example 5

[0218] As described in Predictive Example 1 of patent application WO2019 / 130198A1, a PVDF-STR nano-microstructured antireflective film was prepared using polyvinylidene fluoride (available as PVDF6008 from 3M Company, Maplewood, Minnesota). The smooth sides of the nano-microstructured antireflective film were laminated onto the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M Company). The visible light transmittance of this antireflective film laminated to the glass was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, Maryland) according to ASTM D1003 Method B, with 93.7% for the surface-structured film side 1 facing the light source and 87% for the smooth glass side 2 facing the light source.

[0219] Example 6

[0220] As described in Example 1 of patent application WO2019 / 130198A1, a PVDF-STR nano-microstructured antireflective film was prepared using polyvinylidene fluoride (available as PVDF6008 from 3M Company, Maplewood, Minnesota). The smooth side of the nano-microstructured antireflective film was laminated onto a surface-structured retroreflective film prepared as described in Example 9 of patent application US 11567239 B2, wherein Super Glue (available as 3M Scotch Super Glue from 3M Company, Maplewood, Minnesota) was applied to the outer periphery of the surface-structured side of the retroreflective film. The visible light transmittance of this antireflective film laminated to the retroreflective film was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, Maryland) according to ASTM D1003 Method B, with 87% transmittance on side 1 of the surface-structured antireflective film facing the light source and 25.2% on the smooth side 2 of the retroreflective film facing the light source.

[0221] Example 7

[0222] As described in Example 1 of patent application WO2019 / 130198A1, an LDPE-STR nano-microstructured antireflective film was prepared using low-density polyethylene (available as DOW955i LDPE from Dow Corporation, Midland, Michigan). The smooth side of the nano-microstructured antireflective film was laminated onto a surface-structured retroreflective film prepared as described in Example 9 of patent application US 11567239 B2, wherein Super Glue (available as 3M Scotch Super Glue from 3M Corporation, Maplewood, Minnesota) was applied to the outer periphery of the surface-structured side of the retroreflective film. The smooth side 2 of the retroreflective film was laminated onto the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M Corporation) to produce an antireflective film / retroreflective film / glass laminate composite material. The visible light transmittance of the antireflective film / retroreflective film / glass laminate was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD) according to ASTM D1003 Method B. The transmittance was 85.1% when the surface-structured antireflective film side 1 faced the light source, and 12.4% when the smooth side 2 of the glass faced the light source.

[0223] Example 8

[0224] As described in Example 1 of patent application WO2019 / 130198A1, a PVDF-STR nano-microstructured antireflective film was prepared using polyvinylidene fluoride (available as PVDF6008 from 3M Company, Maplewood, Minnesota). The smooth side of the nano-microstructured antireflective film was laminated onto a surface-structured retroreflective film prepared as described in Example 9 of patent application US 11567239 B2, wherein Super Glue (available as 3M Scotch Super Glue from 3M Company, Maplewood, Minnesota) was applied to the outer periphery of the surface-structured side of the retroreflective film. The smooth side 2 of the retroreflective film was laminated onto the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M Company) to produce an antireflective film / retroreflective film / glass laminate composite material. The visible light transmittance of the antireflective film / retroreflective film / glass laminate was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD) according to ASTM D1003 Method B. The transmittance was 98.6% when the surface-structured antireflective film side 1 faced the light source, and 12% when the smooth side 2 of the glass faced the light source.

[0225] Example 9

[0226] As described in Example 1 of patent application WO2019 / 130198A1, an LDPE-STR nano-microstructured antireflective film was prepared using low-density polyethylene (available as DOW955i LDPE from Dow Corporation, Midland, Michigan). The smooth side of the nano-microstructured antireflective film was laminated to side 1 of the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M Corporation). A surface-structured retroreflective film was prepared as described in Example 9 of patent application US 11567239 B2 and laminated to side 2 of the glass (wherein Super Glue (available as 3M Scotch Super Glue from 3M Corporation, Maplewood, Minnesota) was applied to the outer periphery of the surface-structured side of the retroreflective film) to produce an antireflective film / glass / retroreflective film laminate composite. According to ASTM D1003 Method B, the visible light transmittance of the antireflective film / glass / retroreflective film laminate was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD). The transmittance was 84.7% when the surface-structured antireflective film side 1 faced the light source, and 20.1% when the smooth side 2 of the retroreflective film faced the light source.

[0227] Example 10

[0228] As described in Example 1 of patent application WO2019 / 130198A1, a PVDF-STR nano-microstructured antireflective film was prepared using polyvinylidene fluoride (available as PVDF6008 from 3M Company, Maplewood, Minnesota). The nano-microstructured antireflective film was laminated onto the side 1 of the glass described in Comparative Example 1 using an optically transparent pressure-sensitive adhesive (available as OCA8171 from 3M Company). A surface-structured retroreflective film was prepared as described in Example 9 of patent application US 11567239 B2 and laminated onto the side 2 of the glass (wherein Super Glue (available as 3M ScotchSuper Glue from 3M Company, Maplewood, Minnesota) was applied to the outer periphery of the surface-structured side of the retroreflective film) to produce an antireflective film / glass / retroreflective film laminate composite material. The visible light transmittance of the antireflective / glass / retroreflective laminate was measured using a Haze-Gard Plus translucency meter (available from BYK Gardner, Columbia, MD) according to ASTM D1003 Method B, with 94% transmittance on side 1 of the surface-structured antireflective film facing the light source and 19% transmittance on side 2 of the smooth retroreflective film facing the light source.

[0229] The above description of the present invention is illustrative and not intended to be limiting. Therefore, it should be understood that various additions, substitutions, and modifications can be made to the above embodiments without departing from the scope of the invention. Thus, the scope of the invention should be interpreted with reference to the appended claims.

[0230] Furthermore, it is particularly envisioned that the features described in the appended claims may be arranged in different combinations or sub-combinations without departing from the scope of this disclosure. For example, it is envisioned that features set forth in two or more claims may be combined in a single claim without departing from the scope of this disclosure, regardless of whether the resulting combination of features is explicitly disclosed in the appended claims or elsewhere in the disclosure.

Claims

1. A retroreflective article, the retroreflective article comprising: An anti-reflective layer, the anti-reflective layer comprising a plurality of surface structural elements, the plurality of surface structural elements collectively forming a structured surface opposite to the main surface; and An antireflective layer having a first primary surface and an opposing second primary surface, wherein the second primary surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

2. The retroreflective article according to claim 1, wherein the retroreflective article further comprises an adhesive layer disposed between the retroreflective layer and the antireflective layer.

3. The retroreflective article according to claim 2, wherein the adhesive layer comprises polyethylene terephthalate (PET), crosslinked polysiloxane, silicone thermoplastic polymer, crosslinked polyurethane, thermoplastic polyurethane, crosslinked (meth)acrylate, polymethyl methacrylate (PMMA), copolymer of ethyl acrylate and methyl methacrylate (coPMMA), polyimide, cyclic olefin copolymer, cyclic olefin polymer, polycarbonate, polyisobutylene (PIB), polyvinyl butyrate, butyl rubber (BR), epoxy resin, thiol, thioolefin, or combinations thereof.

4. The retroreflective article according to claim 2 or claim 3, wherein the adhesive layer comprises an optically transparent adhesive, the optically transparent adhesive comprising at least one polyisobutylene resin and a polyfunctional (meth)acrylate monomer.

5. The retroreflective article according to any one of claims 2 to 4, wherein the adhesive layer further comprises at least one of the following: a first UV absorber or a first hindered amine light stabilizer (HALS).

6. The retroreflective article according to any one of claims 1 to 5, wherein the retroreflective article further comprises a barrier layer disposed between the retroreflective layer and the antireflective layer.

7. The retroreflective article according to claim 6, wherein the blocking layer comprises a metal oxide layer, the metal oxide layer comprising at least one of the following: titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, aluminum silicon oxide, or niobium oxide.

8. The retroreflective article according to claim 7, wherein the thickness of the metal oxide layer is 15 nanometers to 60 nanometers (nm).

9. The retroreflective article according to any one of claims 6 to 8, wherein the blocking layer comprises: At least one paired layer, the at least one paired layer comprising a (co)polymer layer and an inorganic layer covering the (co)polymer layer; and an outer (co)polymer layer covering the at least one paired layer; and optionally at least one outer inorganic layer covering the outer (co)polymer layer.

10. The retroreflective article according to claim 9, wherein the at least one paired layer is a plurality of paired layers, optionally wherein the plurality of paired layers is two paired layers, three paired layers, four paired layers, five paired layers or six paired layers.

11. The retroreflective article according to claim 9 or claim 10, wherein the inorganic layer is formed of an inorganic material selected from the group consisting of: silicon oxide, silicon aluminum oxide, silicon oxynitride, gallium oxide, magnesium oxide, niobium oxide, titanium dioxide, yttrium oxide, zinc oxide, tin oxide, nickel oxide, tungsten oxide, aluminum-doped zinc oxide, indium tin oxide, zirconium oxide, zirconium oxynitride, hafnium oxide, aluminum oxide, aluminum-doped silicon oxide, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or combinations thereof.

12. The retroreflective article according to any one of claims 9 to 11, wherein each of the at least one paired layers comprises a copolymer selected from the group consisting of olefin copolymers, (meth)acrylate copolymers, urethane copolymers, silicone copolymers, or combinations thereof.

13. The retroreflective article according to any one of claims 9 to 12, wherein the (co)polymer layer further comprises at least one of: a second UV absorber or a second hindered amine light stabilizer (HALS).

14. The retroreflective article according to any one of claims 1 to 13, wherein the retroreflective article further comprises an optically transparent adhesive attached to the first main surface of the antireflective layer.

15. The retroreflective article according to any one of claims 1 to 14, wherein the retroreflective article exhibits a refractive index difference of 1.49 or greater, 1.51, 1.53, 1.55, 1.57 or 1.59 or greater from the first primary surface of the retroreflective article to the relative primary surface of the retroreflective article.

16. The retroreflective article according to any one of claims 1 to 15, wherein the surface structural element comprises at least one shape having a cross-section selected from the group consisting of ellipse, semicircle, oblong and polygon in a plane parallel to the opposing main surface of the retroreflective layer.

17. The retroreflective article according to any one of claims 1 to 16, wherein the surface structure element comprises at least one shape selected from the group consisting of: a cubic angle, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cubic angle.

18. The retroreflective article according to any one of claims 1 to 17, wherein the antireflective layer comprises a porous gradient layer or a quarter-wavelength antireflective layer.

19. The retroreflective article according to any one of claims 1 to 17, wherein the antireflective layer comprises a structured antireflective layer having a structured first primary surface.

20. The retroreflective article of claim 19, wherein the structured first primary surface comprises a microstructure.

21. The retroreflective article according to claim 19 or claim 20, wherein the structured antireflective layer comprises a matrix and a nanoscale dispersed phase, the structured first main surface has a microstructured surface, and the microstructured surface has a randomly nanostructured anisotropic surface.

22. The retroreflective article according to any one of claims 19 to 21, wherein the structured first primary surface comprises a structured skip tooth pattern.

23. The retroreflective article according to any one of claims 1 to 22, wherein the antireflective layer comprises a fluoropolymer material.

24. A method for retaining light in a greenhouse, the method comprising: The retroreflective article according to any one of claims 1 to 23 is attached to at least one of the transparent roof, wall or window of the greenhouse, wherein the retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the greenhouse.

25. A method for retaining light in a building having windows or skylights, the method comprising: The retroreflective article according to any one of claims 1 to 24 is attached to at least one of the windows or skylights of the building, wherein the retroreflective article is oriented such that the main surface of the retroreflective layer is positioned facing the interior of the building.

26. The method of claim 24 or claim 25, wherein the retroreflective article is attached via an adhesive.

27. The method according to any one of claims 24 to 26, wherein the retroreflective article is suspended on the transparent roof, wall, window or skylight.

28. A kit comprising: An anti-reflective layer, the anti-reflective layer comprising a plurality of surface structural elements, the plurality of surface structural elements collectively forming a structured surface opposite to the main surface; and an anti-reflective layer, the anti-reflective layer having a first main surface and an opposing second main surface.

29. The kit of claim 28, further comprising a pressure-sensitive adhesive or a hot melt adhesive.

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