Retroreflective article including a retroreflective layer and a light down conversion material, kits, and methods thereof

Abstract

The present disclosure provides a retroreflective article. The retroreflective article includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; and a light down conversion material. The light down conversion material is present in at least one of the following: i) the retroreflective layer, ii) an optional second layer, or iii) an optional third layer. The present disclosure also provides a method of conserving light in a greenhouse or a building with windows or skylights. The method includes attaching a retroreflective article to at least one of a transparent roof, wall, or window of the greenhouse, or building wherein the retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the greenhouse. The present disclosure also provides a kit comprising a retroreflective layer, an antireflective layer, and a light down conversion layer.

Description

RETROREFLECTIVE ARTICLE INCLUDING A RETROREFLECTIVE LAYER AND A LIGHT DOWN CONVERSION MATERIAL, KITS, AND METHODS THEREOF TECHNICAL FIELD

[0001] The present disclosure broadly relates to retroreflective articles. In particular, the present disclosure relates to retroreflective articles including a retroreflective layer and a light down conversion material, and its methods thereof. BACKGROUND

[0002] Greenhouses are suitable for growing plants even in extending seasons and these green houses provide a controlled environment for the growth of plants. Additionally, greenhouses facilitate the growth of plants with limited exposure to pests and also provide added security for high valued plants. Hence the use of greenhouses is becoming much more prevalent in organic food industries. However, conventional green houses do not make the best use of solar radiation and further, the majority of the UV radiation may not be required for plant growth. Also, there is irregular distribution of the solar radiation in the green houses resulting in uneven illumination in its interiors.

[0003] Various approaches have been taken to manage the lighting within the green houses. Control of shading and providing supplementary illumination, are the most common approaches taken for illumination of greenhouses. The use of lighting devices, such as LEDs, fluorescent lamps, smart windows, and switchable devices has been widely explored. Further, the use of reflectors in the construction of greenhouse has been found to benefit the growth of plants in greenhouses. However, such approaches often compromise on the amount of useful light reaching the plants and also suffer from a lack of conversion of light of undesired wavelength to the desired wavelength. Furthermore, artificial light escapes from the windows and skylights of buildings requiring the buildings to have more artificial lighting than needed. SUMMARY

[0004] Retroreflectors are useful in designing the walls, roofs, or windows of greenhouses for facilitating desired lighting in the greenhouse. More particularly, the materials in retroreflectors are capable of reflecting incident light back into its incident pathway and / or to its light source. These retroreflectors include various shaped corner or hemsipheric elements, including protruding glass beads, which provide retroreflection. The retroreflectors in general are designed to reflect interior artificial light to minimize light loss out of the greenhouse or building. However, there is a requirement to provide effective illumination within the green house by transmitting solar radiation along with conserving artificial light utilizing retroreflective properties.

[0005] In a first aspect, a retroreflective article is provided. The retroreflective article includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; and a light down conversion material. The light down conversion material is present in at least one of the following: i) the retroreflective layer, ii) an optional second layer 1  attached to the major surface of the retroreflective layer, or iii) an optional third layer attached to the optional second layer opposite the retroreflective layer.

[0006] In a second aspect, a method of conserving light (e.g., in a greenhouse) is provided. The method includes attaching a retroreflective article (the retroreflective article according to the first aspect), to at least one of a transparent roof, wall, or window of the greenhouse or windows or skylights of a building. The retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the greenhouse or building.

[0007] In a third aspect, a kit is provided. The kit includes a retroreflective layer. The retroreflective layer includes a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; an antireflective layer; and a light down conversion layer having a first major surface and an opposing second major surface.

[0008] The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0010] FIG.2 is a schematic cross-sectional view of an exemplary embodiment of a retroreflective article including a second layer according to the present disclosure.

[0011] FIG. 3a-3c are a schematic cross-sectional view of exemplary embodiments of retroreflective articles including a barrier layer according to the present disclosure.

[0012] FIG.4 is a schematic cross-sectional view of another exemplary embodiment of a retroreflective article including a third layer according to the present disclosure.

[0013] FIG.5 is a schematic cross-sectional view of an exemplary embodiment of a retroreflective article including an antireflective layer according to the present disclosure.

[0014] While the above-identified figures set forth several embodiments of the disclosure, other embodiments are also contemplated, as noted in the description. The figures are not necessarily drawn to scale. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 2

[0015] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

[0016] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in light of the remainder of the disclosure and as understood by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0017] As used herein, the term "at least one" is used to mean one or more and thus includes individual components as well as mixtures / combinations.

[0018] The term “barrier layer” refers to a layer which is designed to be impervious or resistant to ultraviolet radiation, water, and / or oxygen.

[0019] The terms “(co)polymer” includes homo(co)polymers and (co)polymers, as well as homo(co)polymers or (co)polymers that may be formed in a miscible blend, (e.g., by coextrusion or by reaction, including, (e.g., transesterification. The term “(co)polymer” includes random, block and star (e.g., dendritic) (co)polymers.

[0020] The term "(meth)acryl" or “(meth)acrylate” with respect to a monomer, oligomer, (co)polymer or compound means a vinyl-functional alkyl ester formed as the reaction product of an alcohol with an acrylic or a methacrylic acid.

[0021] The term “optically clear” refers to a material in which there is no visibly noticeable distortion, haze or flaws as detected by the naked eye at a distance of about 1 meter, preferably about 0.5 meters.

[0022] The term “overlaying” refers to describing the position of a layer with respect to a substrate, dyad or a different layer. “Overlaying” refers to the layer as being atop the substrate, dyad or different layer, but not necessarily contiguous to or in contact with the substrate, dyad or different layer, although the layer may, in some embodiments, be in direct contact with the substrate, dyad or different layer.

[0023] The term “dyad” refers to a pair of layers that includes a (co)polymer layer and an oxide layer overlaying the (co)polymer layer. The term “plurality of dyads” refers to more than one dyad, i.e., refers to at least two pairs of layers having a (co)polymer layer and an oxide layer overlaying the (co)polymer layer. Plurality of dyads can be two dyads, three dyads, four dyads, five dyads, or six dyads.

[0024] The term “layer” refers to a single stratum within a multilayer film.

[0025] The term “attached” with respect to two layers being attached, encompasses both options of being directly attached or having one or more layers disposed in between the two attached layers. 3

[0026] The words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the disclosure.

[0027] As used herein, the terms such as “a”, “an”, and “the” are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms “a”, “an”, and “the” are used interchangeably with the term “at least one”. The phrases “at least one of’ and “comprises” at least one of’ followed by a list refer to any one of the items in the list and any combination of two or more items in the list.

[0028] As used herein, the term “or” is generally employed in its usual sense including “and / or” unless the content clearly dictates otherwise.

[0029] As used herein, the term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0030] As used herein, the terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. Throughout this specification, unless the context requires otherwise the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or steps.

[0031] The terms “including” is used to mean “including but not limited to”, “including” and “including but not limited to” are used interchangeably.

[0032] Also herein, all numbers are assumed to be modified by the term “about” and preferably by the term “exactly.” As used herein in connection with a measured quantity, the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0033] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties). The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring errors applicable to the particular circumstance rather than requiring absolute precision or a perfect match. 4

[0034] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0035] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein. Retroreflective Article

[0036] In a first aspect, the present disclosure provides a retroreflective article. The retroreflective article includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; and a light down conversion material. The light down conversion material is present in at least one of the following: i) the retroreflective layer, ii) an optional second layer attached to the major surface of the retroreflective layer, or iii) an optional third layer attached to the optional second layer opposite the retroreflective layer.

[0037] A retroreflective article of the present disclosure refers to an arrangement or a construction that constitutes layered materials of optical shape, optical components, and / or structure capable of retroreflecting incident light.

[0038] Referring to FIG.1, the present disclosure describes the retroreflective article (100) which includes a retroreflective layer (110). The retroreflective layer comprises plurality of surface structure elements (110a) that collectively form a structured surface that is opposite a major surface (110b). The surface structure elements (110a) of the retroreflective layer include at least one shape having a cross section, in a plane parallel to the opposing major surface of the retroreflective layer, and may be selected from the group consisting of ellipsoidal, semicircular, oblong, and polygonal. The surface structure elements (110a) of the retroreflective layer comprise at least one shape that may be selected from the group consisting of a cube corner, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cube corner. The retroreflective layer includes a light down conversion material. The light down conversion material includes at least one material selected from the group consisting of a plurality of quantum dots, an optical brightener, a phosphorescent material, and combinations thereof.

[0039] FIG.2 illustrates another embodiment of the retroreflective article (200). The retroreflective article comprises a retroreflective layer (210) and a second layer (220). The retroreflective layer comprises a structured surface (210a) which includes a plurality of surface structure elements; and an opposing major surface (210b). The second layer is attached to the major surface of the retroreflective layer (210b). The second layer (220) comprises a matrix. Further, the matrix of the second layer includes a light down conversion material dispersed in it. In some embodiments, the matrix of the second layer comprises an optically clear adhesive. The optically clear adhesive typically includes at least one polyisobutylene resin 5  and a multifunctional (meth)acrylate monomer. Some suitable optically clear adhesives are described in detail, for instance, in U.S. Pat. No.8,232,350 (Fujita et al.). In certain cases, the matrix of the second layer additionally includes at least one of a UV absorber, a hindered amine light stabilizer (HALS), or an antioxidant. In some embodiments, the second layer (220) is a barrier layer and the second layer includes a light down conversion material. In certain other embodiments, the second layer is a tie layer.

[0040] FIG. 3 (a, b, and c) corresponds to a cross sectional view of the retroreflective article (300) according to various embodiments described herein. The retroreflective article (300) comprises a retroreflective layer (310) which has a structured surface (310a) which includes a plurality of surface structure elements; and an opposing major surface (310b). The retroreflective article (300) includes a second layer (320) which has a first major surface (320a) and an opposing second major surface (320b). The retroreflective article according to an embodiment herein includes a third layer that is a barrier layer (330). The barrier layer (330) is attached to at least one of the first major surface (320a) and / or the second major surface (320b) of the second layer (320). The retroreflective article as described in FIG. 3a has a barrier layer (330) attached to the second major surface (320b) of the second layer (320). FIG.3b depicts the retroreflective article wherein the barrier layer (330) is disposed between the retroreflective layer (310) and the second layer (320). The barrier layers (330a and 330b) of the retroreflective article can be attached to each of the first major surface (320a) and the second major surface (320b) of the second layer (320) as shown in FIG.3c. In some embodiments, the second layer (320) is a barrier layer. The at least one barrier layer of various embodiments herein, independently comprises a metal oxide layer or at least one dyad. In other embodiments, the second layer includes a light down conversion material. In certain other embodiments, the second layer is a tie layer.

[0041] FIG.4 illustrates one exemplary embodiment of the retroreflective article (400). The retroreflective article includes a retroreflective layer (410) with a structured surface (410a) and an opposing major surface (410b). The structured surface is collectively formed from a plurality of surface elements which include at least one shape having a cross section, in a plane parallel to the opposing major surface (410b) of the retroreflective layer, selected from the group consisting of ellipsoidal, semicircular, oblong, and polygonal. The retroreflective article (400) includes a second layer (420) and a third layer (430). The second layer has a first major surface (420a) and the second major surface (420b). The third layer (430) is attached to the second layer (420) opposite the retroreflective layer (410). The second layer is attached to the major surface of the retroreflective layer (410b). In one embodiment, the second layer is a tie layer. In some embodiments, the third layer has a light down conversion material. In other embodiments, the third layer is a barrier layer attached to the second major surface of the second layer. In certain other embodiments, the second layer is a tie layer, and the third layer includes the light down conversion material. In various embodiments, the third layer comprises a matrix and a light down conversion material distributed in the matrix.

[0042] FIG. 5 further illustrates an additional embodiment of the retroreflective article (500). The retroreflective article includes a retroreflective layer (510) with a structured surface (510a) and an opposing major surface (510b). The retroreflective article (500) includes a second layer (520) and may optionally 6  include a third layer according to other embodiments disclosed herein. The retroreflective article further includes an antireflective layer (530). The antireflective layer (530) has a first major surface (530a) and an opposing second major surface (530b). The second major surface (530b) of the antireflective layer (530) is attached to the structured surface (510a) of the retroreflective layer (510). In some embodiments, the antireflective layer includes a porous gradient or a quarter wave antireflective layer. In the embodiment shown in FIG.5, the antireflective layer includes a structured antireflective layer having a structured first major surface (535). In some cases, the structured first major surface (535) comprises microstructures. The structured first major surface (535) of the antireflective layer may have a skipped tooth pattern of structures (537). The skipped tooth patterns have micro-peaks (537a) and micro-spaces (537b). Each of the micro- peaks (537a) and micro-spaces (537b) may include at least one straight segment or curved segment. Each of the micro-peaks and micro-spaces optionally comprise nano-structures on their surfaces. Optionally, the structured antireflective layer includes a matrix and a nanoscale dispersed phase. Such a structured surface has a microstructured surface that has a random nanostructured anisotropic surface thereon.

[0043] The structured surface of the retroreflective layer has a plurality of minute surface structure elements arranged to reflect a substantial portion of the incident light and transmit a substantial portion. The reflectivity of the surface is changed primarily by this change in the local geometry. Useful structures include linear prisms, pyramidal prisms with triangular, square, hexagonal or other polygonal bases, cones, hemispheres, a quarter sphere, a truncated cube corner and ellipsoids, which structures may be in the form of projections extending out from a surface or pits extending into the surface. Hemispheres may be created with glass beads protruding from the surface. The size, shape, geometry, orientation, and spacing of the structures, as well as the use of multiple, different structures (e.g., different sizes, shapes, geometries, orientations, etc.), and density of spacing, can all be selected to optimize the performance of the light assembly or otherwise provide a desired effect. The individual structures can be symmetric and / or asymmetric. The structured surface can be uniform and / or non-uniform, and in the latter case both the position and size of the structures can be random or pseudo-random. In this context, “uniform” is understood to mean that the structured surface includes a repeating structural pattern. Disrupting regular features by periodic or pseudo-random variation of size, shape, geometry, orientation, and / or spacing may be used to adjust the color and / or brightness uniformity of the retroreflective layer. In some cases, it may be beneficial to have a distribution of small and large structures and position the retroreflective layer such that the smaller structures are aligned generally over the light sources and the larger structures are positioned elsewhere. In some embodiments, the structures can be closely packed such that there is minimal land (including arrangements in which there is substantially no land) between structures. In some embodiments, it may be desirable to control the land area to modulate the amount of light passing through the retroreflective layer.

[0044] The retroreflective article includes a retroreflective layer which comprises a plurality of surface structure elements that collectively form a structured surface. The surface structure elements of the retroreflective layer include at least one shape having a cross section, in a plane parallel to the opposing 7  major surface of the retroreflective layer, selected from the group consisting of ellipsoidal, semicircular, oblong, and polygonal. The surface structure elements of the retroreflective layer include at least one shape selected from the group consisting of a cube corner, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cube corner. As such, the structured surface is nonplanar.

[0045] Examples of suitable retroreflective structured surfaces can be found in commercially available reflective sheeting available from 3M Company, St. Paul, MN, under the trade designations “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”.

[0046] Examples of suitable structured surfaces include commercial one-dimensional (linear) prismatic polymeric films such as available from 3M Company, St. Paul, Minn., under the trade designations “VIKUITI BRIGHTNESS ENHANCEMENT FILM,” “VIKUITI TRANSMISSIVE RIGHT ANGLE FILM,” VIKUITI IMAGE DIRECTING FILM,” and “VIKUITI OPTICAL LIGHTING FILM,” well as conventional lenticular linear lens arrays.

[0047] Additional examples of suitable structured surfaces, where the structured surface has a two- dimensional character, include cube corner surface configurations such as those described in U.S. Pat. No. 4,588,258 (Hoopman), U.S. Pat. No.4,775,219 (Appeldorn et al.), U.S. Pat. No.5,138,488 (Szczech), U.S. Pat. No.5,122,902 (Benson), U.S. Pat. No.5,450,235 (Smith et al.), and U.S. Pat. No.5,840,405 (Shusta et al.); inverted prism surface configurations such as described in U.S. Pat. No. 6,287,670 (Benson et al.) and U.S. Pat. No. 6,280,822 (Smith et al.); structured surface films such as described in U.S. Pat. No. 6,752,505 (Parker et al.) and U.S. Pat. Publication No.2005 / 0024754 (Epstein et al.); and beaded sheeting such as that described in U.S. Pat. No.6,771,335 (Kimura et al.), the disclosures of which are incorporated herein by reference. Light down conversion material

[0048] The light down conversion material of the present disclosure refers to materials that are capable of converting an input light of a shorter wavelength to an output light of a longer wavelength. Light down conversion materials also refer to materials that can generate visible or near infra-red photons by absorbing a UV photon. The light down conversion material is selected from a group consisting of plurality of quantum dots, an optical brightener, a phosphorescent material, and combinations thereof.

[0049] The light down conversion material of the present disclosure is present in at least one of the following i) the retroreflective layer, ii) an optional second layer attached to the major surface of the retroreflective layer, or iii) an optional third layer attached to the optional second layer opposite the retroreflective layer.

[0050] The light down conversion material is optionally present in the second layer. Such a second layer includes a matrix and the light down conversion material is distributed in the matrix. Additionally or alternatively, the light down conversion material can be present in the third layer. 8

[0051] In some embodiments, a kit includes a light down conversion layer having a first major surface and an opposing second major surface, and the layer comprises the light down conversion material.

[0052] In certain cases, the light down conversion material comprises a plurality of quantum dots. Quantum dots are nanoparticle semiconducting materials which have electronic and optical properties that are size-dependent due to quantum confinement. The dimension of the quantum dots are preferably has at least one dimension less than about 50 nanometers, more preferably less than 30 nm. Optionally, quantum dots may be colloidal quantum dots, i.e., quantum dots that may remain in suspension when dispersed in a liquid medium. Some of the quantum dots which may be utilized in the articles, kits and methods described herein are made from a binary semiconductor material having a formula MX, where M is a metal and X typically is selected from sulfur, selenium, tellurium, nitrogen, phosphorus, arsenic, antimony, or mixtures thereof. Exemplary binary quantum dots which may be utilized include CdS, CdSe, CdTe, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, Cu2S, and In2S3. Other quantum dots which may be utilized in the articles, kits, and methods described herein are ternary, quaternary, and / or alloyed quantum dots including, but not limited to, ZnSSe, ZnSeTe, ZnSTe, CdSSe, CdSeTe, HgSSe, HgSeTe, HgSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnHgS, ZnHgSe, ZnHgTe, CdHgS, CdHgSe, CdHgTe, ZnCdSSe, ZnHgSSe, ZnCdSeTe, ZnHgSeTe, CdHgSSe, CdHgSeTe, CuInS2, CuInSe2, CuInGaSe2, CuInZnS2, CuZnSnSe2, CuIn(Se,S)2, CuInZn(Se,S)2, and AgIn(Se,S)2quantum dots, although the use of non-toxic quantum dots is preferred. Embodiments of the disclosed quantum dots may be of a single material or may comprise an inner core and an outer shell (e.g., a thin outer shell / layer formed by any suitable method, such as cation exchange). These shell materials can be combinations of materials such as but not limited to the binary, ternary and quaternary materials as described above. The shells may also have a gradiated composition from the core to the shell. The quantum dots may further include a plurality of ligands bound to the quantum dot surface. These ligands can include a number of types of organic compounds including but not limited to carboxylic acids, amines and thiol compounds or combination of materials.

[0053] In some embodiments, two or more distinct types of quantum dots may be utilized in the articles, kits, and methods described herein. These quantum dots may be compositionally distinct. For example, the light down conversion materials utilized herein may comprise a first type of quantum dot based on a first chemistry, and a second type of quantum dot based on a second chemistry which is distinct from the first chemistry. Thus, for example, the first type of quantum dot may comprise CuInS2, while the second type of quantum dot may comprise AgInSe2. Similarly, the light down conversion materials described herein may comprise a first type of quantum dot based on a first set of dimensions (or distribution of dimensions) of the quantum dots, and a second type of quantum dot based on a second set of dimensions (or distribution of dimensions) of the quantum dots which is distinct from the first set of dimensions (or distribution of dimensions) of the quantum dots. Thus, for example, the first type of quantum dot may comprise generally spherical quantum dots having a first diameter (e.g., 10 nm), and the second type of quantum dot may comprise generally spherical quantum dots having a second diameter (e.g., 30 nm). Reference is made to U.S. Pat. No.11,569,402 (Hunter et al.) for such quantum dots. 9

[0054] Phosphorescent materials and optical brighteners are also useful as light down conversion materials. In certain cases, the light down conversion material comprises a phosphorescent material. Examples of phosphorescent materials include but is not limited to doped inorganic oxides or nitrides, and semiconductors including group II-VI and III-V metals. In certain cases, the light down conversion material comprises an optical brightener. Examples of optical brighteners include but is not limited to disulphonates, tetrasulphonates, hexasulphonates, stilbene derivatives, benzoxazole derivatives, imidazole derivatives, coumarin derivatives, and Tinopal OB, a benzoxazole, 2,2'-(2,5-thiophenediyl)bis[5-(l, l-dimethylethyl)], available from BASF Corporation, Florham Park, NJ. Matrix

[0055] The light down conversion material of the present disclosure is often dispersed in a matrix. The matrix typically includes polymers. Useful polymeric materials include thermoplastics and thermosetting resins. Suitable thermoplastics include but are not limited to, polyethylene terephthalate (PET), polystyrene, acrylonitrile butadiene styrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyacrylates, thermoplastic polyurethanes, polyvinyl acetate, polyamide, polyimide, polypropylene, polyester, polyethylene, poly(methylmethacrylate), polyethylene naphthalate, styrene acrylonitrile, silicone- polyoxamide polymers, fluoropolymers, cyclic olefin copolymers, thermoplastic elastomers, poly(meth)acrylate, siloxane, urethane, epoxy, cyclic olefin copolymer, triacetate cellulose, diacrylate cellulose, and the like.

[0056] Suitable thermosetting resins include, but are not limited to, allyl resin (including (meth)acrylates, polyester acrylates, urethane acrylates, epoxy acrylates and polyether acrylates), epoxies, thermosetting polyurethanes, silicones or polysiloxanes, and the like. These resins can be formed from the reaction product of polymerizable compositions comprising the corresponding monomers and or oligomers.

[0057] In one embodiment, the polymerizable compositions include at least one monomeric or oligomeric (meth)acrylate, preferably a urethane (meth)acrylate. Typically the monomeric or oligomeric (meth)acrylate is multi(meth)acrylate. The term “(meth)acrylate” is used to designate esters of acrylic and methacrylic acids, and “multi(meth)acrylate” designates a molecule containing more than one (meth)acrylate group, as opposed to “poly(meth)acrylate” which commonly designates (meth)acrylate polymers. Most often, the multi(meth)acrylate is a di(meth)acrylate, but it is also contemplated to employ tri(meth)acrylates, tetra(meth)acrylates and so on.

[0058] Suitable monomeric or oligomeric (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, 1-propyl (meth)acrylate and t-butyl (meth)acrylate. The acrylates may include (fluoro)alkylester monomers of (meth)acrylic acid, the monomers being partially and or fully fluorinated, such as, trifluoroethyl (meth)acrylate.

[0059] Examples of commercially available multi(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 10  ARONIX series from Toagosei Co., LTD.; the BLENMER series manufactured by NOF Corp.; the KAYARAD series from Nippon Kayaku Co., Ltd., the LIGHT ESTER series and LIGHT ACRYLATE series from Kyoeisha Chemical Co., Ltd.

[0060] Oligomeric urethane multi(meth)acrylates may be obtained commercially, for example from Sartomer under the trade designation “Photomer 6000 Series”, such as “Photomer 6010” and “Photomer 6020”, and also under the trade designation “CN 900 Series”, such as “CN966B85”, “CN964” and “CN972”. Oligomeric urethane (meth)acrylates are also available from Surface Specialties, such as available under the trade designations “Ebecryl 8402”, “Ebecryl 8807” and “Ebecryl 4827”. Oligomeric urethane (meth)acrylates may also be prepared by the initial reaction of an alkylene or aromatic diisocyanate of the formula OCN—R3—NCO with a polyol. Most often, the polyol is a diol of the formula HO—R4—OH where R3is a C2-C100alkylene or an arylene group and R4is a C2-C100alkylene group. The intermediate product is then a urethane diol diisocyanate, which subsequently can undergo reaction with a hydroxyalkyl (meth)acrylate. Suitable diisocyanates include 2,2,4-trimethylhexylene diisocyanate and toluene diisocyanate. Alkylene diisocyanates are generally preferred. A particularly preferred compound of this type may be prepared from 2,2,4-trimethylhexylene diisocyanate, poly(caprolactone)diol and 2- hydroxyethyl methacrylate. In at least some cases, the urethane (meth)acrylate is preferably aliphatic.

[0061] The polymerizable compositions can be mixtures of various monomers and or oligomers, having the same or differing reactive functional groups. Polymerizable compositions comprising two or more different functional groups may be used, including the following; (meth)acrylate, epoxy and urethane. The differing functionality may be contained in different monomeric and or oligomeric moieties or in the same monomeric and or oligomeric moiety. For example, a resin composition may comprise an acrylic or urethane resin having an epoxy group and or a hydroxyl group in the side chain, a compound having an amino group and, optionally, a silane compound having an epoxy group or amino group in the molecule.

[0062] The thermosetting resin compositions are polymerizable using conventional techniques such as thermal cure, photocure (cure by actinic radiation) and or e-beam cure. In one embodiment, the resin is photopolymerized by exposing it to ultraviolet (UV) and or visible light. Conventional curatives and or catalyst may be used in the polymerizable compositions and are selected based on the functional group(s) in the composition. Multiple curatives and or catalysts may be required if multiple cure functionality is being used. Combining one or more cure techniques, such as thermal cure, photocure and e-beam cure, is within the scope of the present disclosure.

[0063] Furthermore, the polymerizable resins can be compositions comprising at least one other monomer and or oligomer (that is, other than those described above, namely the monomeric or oligomeric (meth)acrylate and the oligomeric urethane (meth)acrylate). This other monomer may reduce viscosity and / or improve thermomechanical properties and / or increase refractive index. Monomers having these properties include acrylic monomers (that is, acrylate and methacrylate esters, acrylamides and methacrylamides), styrene monomers and ethylenically unsaturated nitrogen heterocycles. 11

[0064] Also included are (meth)acrylate esters having other functionality. Compounds of this type are illustrated by the 2-(N-butylcarbamyl)ethyl (meth)acrylates, 2,4-dichlorophenyl acrylate, 2,4,6- tribromophenyl acrylate, tribromophenoxylethyl acrylate, t-butylphenyl acrylate, phenyl acrylate, phenyl thioacrylate, phenylthioethyl acrylate, alkoxylated phenyl acrylate, isobornyl acrylate and phenoxyethyl acrylate. The reaction product of tetrabromobisphenol A diepoxide and (meth)acrylic acid is also suitable.

[0065] The other monomer may also be a monomeric N-substituted or N,N-disubstituted (meth)acrylamide, especially an acrylamide. These include N-alkylacrylamides and N,N- dialkylacrylamides, especially those containing C1-4alkyl groups. Examples are N-isopropylacrylamide, N- t-butylacryl amide, N,N-dimethylacrylamide and N,N-diethylacrylamide.

[0066] The other monomer may further be a polyol multi(meth)acrylate. Such compounds are typically prepared from aliphatic diols, triols, and / or tetraols containing 2-10 carbon atoms. Examples of suitable poly(meth)acrylates are ethylene glycol diacrylate, 1,6-hexanediol diacrylate, 2-ethyl-2-hydroxymethyl- 1,3-propanediol triacylate (trimethylolpropane triacrylate), di(trimethylolpropane) tetraacrylate, pentaerythritol tetraacrylate, the corresponding methacrylates and the (meth)acrylates of alkoxylated (usually ethoxylated) derivatives of said polyols. Monomers having two or more (ethylenically unsaturated groups can serve as a crosslinker.

[0067] Styrenic compounds suitable for use as the other monomer include styrene, dichlorostyrene, 2,4,6- trichlorostyrene, 2,4,6-tribromostyrene, 4-methylstyrene and 4-phenoxystyrene. Ethylenically unsaturated nitrogen heterocycles include N-vinylpyrrolidone and vinylpyridine.

[0068] Constituent proportions in the radiation curable materials can vary. In general, the organic component can comprise about 30-100% monomeric and or oligomeric (meth)acrylate or oligomeric urethane multi(meth)acrylate, with any balance being the other monomer and or oligomer

[0069] Commercially available liquid-resin based materials (typically referred to as “hardcoats”) may be used as the matrix or as a component of the matrix. Such materials include the PERMANEW series from California Hardcoating Co., San Diego, Calif. and the UVHC series harcoats from Momentive Performance Materials, Albany, N.Y. Additionally, commercially available nanoparticle filled matrix may be used, such as NANOCRYL and NANOPDX from Nanoresins AG, Geesthacht Germany.

[0070] Additionally, nanoparticulate containing hardcoat films, such as THS series from Toray Advanced Films Co., Ltd., Tokyo, Japan; the Opteria Hardcoated Films for FPD from Lintec Corp., Tokyo, Japan; the Sony Optical Film from Sony Chemical & Device Corp., Tokyo, JP; the Hardcoated Film from SKC Haas, Seoul, Korea and the Terrappin G film from Tekra Corp., Milwaukee, Wis., may be used as the matrix or a component of the matrix.

[0071] Surface levelling agents may be added to the matrix. The levelling agent is preferably used for smoothing the matrix resin. Examples include silicone-levelling agents, acrylic-levelling agents and fluorine-containing-leveling agents. In one embodiment, the silicone-levelling agent includes a polydimethyl siloxane backbone to which polyoxyalkylene groups are added. 12

[0072] In select embodiments, the matrix comprises at least one inorganic material. Useful inorganic materials for the matrix include, for example, glasses, metals, metal oxides, and ceramics. Preferred inorganic materials include silicon oxide, zirconia, vanadium pentoxide, and tungsten carbide.

[0073] In some embodiments, the matrix includes a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, a polyethylene naphthalate (PEN), a polyisobutylene (PB), a polyvinyl butyrate (PVB), a butyl rubber (BR), an epoxy, a thiol, a thiolene, or combinations thereof.

[0074] In some embodiments, the matrix includes an optically clear adhesive. The optically clear adhesive includes at least one polyisobutylene resin and a multifunctional (meth)acrylate monomer. In some embodiments, the adhesive comprises a polyisobutylene resin having a weight average molecular weight of 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 multifunctional (meth)acrylate monomer; and the adhesive is substantially free of tackifier. The polyisobutylene may comprise at least about 50 wt. % of the total weight of the adhesive. A multifunctional (meth)acrylate monomer may also be included in the adhesive of this embodiment. When such a monomer is used, the adhesive may comprise from about 60 to about 90 wt. % of the polyisobutylene resin; and from about 10 to about 20 wt. % of the multifunctional (meth)acrylate monomer; all relative to the total weight of the adhesive.

[0075] In some embodiments, the adhesive includes a first polyisobutylene resin having a weight average molecular weight of greater than about 300,000 g / mol; and a second polyisobutylene resin having a weight average molecular weight of less than about 100,000 g / mol, wherein the adhesive is substantially free of tackifier. In this embodiment, the first isobutylene resin may have a weight average molecular weight of greater than about 400,000 g / mol. In this embodiment, the first isobutylene resin may also have a weight average molecular weight of greater than about 1,000,000 g / mol. The first polyisobutylene may comprise at least about 50 wt. % of the total weight of the adhesive. The adhesive may comprise: from about 50 to about 80 wt. % of the first polyisobutylene resin; from about 10 to about 30 wt. % of the second polyisobutylene resin; and from about 10 to about 20 wt. % of the multifunctional (meth)acrylate monomer; all relative to the total weight of the adhesive.

[0076] In some embodiments, the adhesive includes a second polyisobutylene resin having a weight average molecular weight of less than about 300,000 g / mol; a multifunctional (meth)acrylate monomer; and a tackifier, wherein the adhesive is free of a first polyisobutylene having a weight average molecular weight of greater than about 300,000 g / mol. The second isobutylene resin may have a weight average molecular weight of less than about 100,000 g / mol. The adhesive of this embodiment may comprise: from about 10 to about 50 wt. % of the second polyisobutylene resin; from about 10 to about 40 wt. % of the multifunctional (meth)acrylate monomer; from about 0 to about 60 wt. %, or from about 30 to about 60 wt. %, of the tackifier; all relative to the total weight of the adhesive. 13

[0077] In some embodiments, the adhesive includes a first polyisobutylene resin having a weight average molecular weight of greater than about 300,000 g / mol, wherein the first polyisobutylene resin comprises 20 wt. % or less of the total weight of the adhesive; a second polyisobutylene resin having a weight average molecular weight of less than about 300,000 g / mol; a multifunctional (meth)acrylate monomer; and a tackifier. In this embodiment, the first isobutylene resin may have a weight average molecular weight of greater than about 1,000,000 g / mol. The adhesive may comprise: from about 10 to about 30 wt. % of the second polyisobutylene resin; from about 10 to about 30 wt. % of the multifunctional (meth)acrylate monomer; from about 0 to about 60 wt. %, or from about 40 to about 60 wt. %, of the tackifier; all relative to the total weight of the.

[0078] The first and second polyisobutylene resins are generally resins having a polyisobutylene resin skeleton in the main or a side chain. In some embodiments, the first and second polyisobutylene resins are substantially homopolymers of isobutylene, for example, polyisobutylene resins available under the tradenames 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. Synthetic rubbers include butyl rubbers which are copolymers of mostly isobutylene with a small amount of isoprene, for example, butyl rubbers available under the tradenames VISTANEX (Exxon Chemical Co.) and JSR BUTYL (Japan Butyl Co., Ltd.). Synthetic rubbers also include copolymers of mostly 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.

[0079] The polyisobutylene resins generally have a solubility parameter (SP value), which is an index for characterizing the polarity of a compound, that is similar to that of hydrogenated cycloaliphatic hydrocarbon resins, and exhibits good compatibility (i.e., miscibility) with hydrogenated cycloaliphatic hydrocarbon resins, if used, so that a transparent film can be formed. Furthermore, the polyisobutylene resins have low surface energy and therefore can enable the spreadability of the adhesive onto an adherent and the generation of voids at the interface is minimized. In addition, the glass transition temperature and the moisture permeability are low and therefore, the polyisobutylene resins are suitable as the base resin of the adhesive.

[0080] The polyisobutylene resins may have desirable viscoelastic properties that, in general, can be used to impart a desired degree of fluidity to the adhesive. A strain rheometer may be used to determine elastic (storage) modulus, G′, and viscous (loss) modulus, G″, at various temperatures. G′ and G″ can then be used to determine the ratio tan(δ)=G″ / G. In general, the higher the tan(δ) value, the more the material is like a viscous material, and the lower the tan(δ) value, the more the material is like an elastic solid. In some embodiments, the polyisobutylene resin may be selected such that the adhesive has a tan(δ) value at a 14  relatively low frequency of at least about 0.5 when the composition is at temperatures of from about 70° C. to about 110° C. In this way, the adhesive is able to flow sufficiently over uneven surfaces with little or no air entrapment.

[0081] Desirable viscoelastic properties of the adhesive may be obtained with a first polyisobutylene resin having a weight average molecular weight of greater than about 300,000 g / mole, or greater than 1,000,000, when used in combination with a multifunctional (meth)acrylate monomer without any tackifier. Further, desirable viscoelastic properties of the adhesive may be obtained with greater than about 50 wt. % of the first polyisobutylene relative to the total weight of the adhesive.

[0082] The multifunctional (meth)acrylate monomer of the adhesive can be saturated or unsaturated and can include aliphatic, alicyclic, aromatic, heterocyclic, and / or epoxy functionality. In some embodiments, saturated long-chain alkyl(meth)acrylates, cycloaliphatic(meth)acrylates, (meth)acrylate / epoxy monomers, or combinations thereof can be utilized as monomers because they can enhance the miscibility of the polyisobutylene resin and optional tackifier. The multifunctional (meth)acrylate monomer can be unsubstituted or substituted with various groups such as hydroxy or alkoxy groups.

[0083] Exemplary long chain alkyl(meth)acrylates include, but are not limited to, octyl(meth)acrylate, stearyl(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decandiol di(meth)acrylate, and hydrogenated polybutadiene di(meth)acrylate resin. Exemplary cycloaliphatic(meth)acrylates include, but are not limited to, isobornyl(meth)acrylate, tetramethylpiperidiyl methacrylate, pentamethylpiperidiyl methacrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl(meth)acrylate, tricyclodecanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, and (meth)acrylated epoxies.

[0084] In some embodiments, multifunctional (meth)acrylate monomers having two, three, four, or even more than four (meth)acrylate groups may be utilized. It will also be understood by one of skill in the art that mixtures of multifunctional (meth)acrylate monomers can be utilized.

[0085] The multifunctional (meth)acrylate monomer may be selected so as to optimize the adhesion and wettability of the adhesive for adherence with respect to the polyisobutylene resin. The multifunctional (meth)acrylate monomer can increase the adhesion and retention strength of the adhesive because the monomer is cured to form a resin.

[0086] Often, a matrix of the present disclosure further includes at least one UV absorber, hindered amine light stabilizer (HALS), or an antioxidant.

[0087] It is noted that the term “ultraviolet absorber” refers to materials that absorb light having a wavelength below 400 nm but do not emit the absorbed light in a range of from 400 nm to 1200 nm. Examples of ultraviolet absorbers include but are not limited to, benzotriazole-based compounds, oxazolic acid amide-based compounds, and benzophenone-based compounds. The ultraviolet absorber, when used, can be used in an amount from about 0.01 to 10 wt. % based on the total amount of adhesive in the matrix. 15

[0088] Examples of other UV absorbers include but not limited to 2-(2′-hydroxyphenyl)benzotriazoles, for example 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-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′-octyloxyphenyl)benzotriazole, 2-(3′,5′-di-tert-amyl-2′- hydroxyphenyl)benzotriazole, 2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, 2-(3′- tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)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- octyloxycarbonylethyl)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 further include compounds belonging to the groups such as, 4-hydroxybenzoates, esters of substituted and unsubstituted benzoic acids, acrylates, and nickel complexes. Reference may be made to U.S. Pat. Application no 2008 / 0033080 (Dietmar et al.) for such UV absorbers.

[0089] Examples of hindered amine light stabilizers include but not limited to bis(2,2,6,6-tetramethyl-4- piperidyl)succinate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, the condensate of 1-(2- hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensates of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro- 1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4- piperidyl)-1,2,3,4-butanetetracarboxylate, 1,1′-(1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone), 4- benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6- pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9- tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, linear or cyclic condensates of N,N′-bis(2,2,6,6- tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3- aminopropylamino)ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6- pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, 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- piperidyl)pyrrolidine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensate of N,N′- bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5- triazine, a condensate of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine as well as 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); a condensate of 1,6- hexanediamine and 2,4,6-trichloro-1,3,5-triazine as well as N,N-dibutylamine and 4-butylamino-2,2,6,6- tetramethylpiperidine (CAS Reg. No. [192268-64-7]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n- 16  dodecylsuccinimide, N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9- tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9-tetramethyl-2- cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]decane and epichlorohydrin, 1,1-bis(1,2,2,6,6- pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene, N,N′-bis-formyl-N,N′-bis(2,2,6,6- tetramethyl-4-piperidyl)hexamethylenediamine, a diester of 4-methoxymethylenemalonic acid with 1,2,2,6,6-pentamethyl-4-hydroxypiperidine, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4- piperidyl)]siloxane, a reaction product of maleic acid anhydride-α-olefin copolymer with 2,2,6,6- tetramethyl-4-aminopiperidine or 1,2,2,6,6-pentamethyl-4-aminopiperidine; HA-6). Hindered amine light stabilizers further include compounds belonging to the groups such as, oxamides, 2-(2-hydroxyphenyl)- 1,3,5-triazines, metal deactivating compounds, phosphites, phosphonites, hydroxylamines, and nitrones. Reference may be made to U.S. Pat. Application no 2008 / 0033080 (Dietmar et al.) for such hindered amine light stabilizers. The hindered amine light stabilizers, when used, can be used in an amount from about 0.01 to 3 wt. % based on the total amount of adhesive in the matrix.

[0090] Examples of antioxidants that can be used include, but are not limited to, hindered phenol-based compounds, phosphoric acid ester-based compounds, alkylated monophenols, alkylthiomethylphenols, hydroquinones, alkylated hydroquinones, tocopherols, hydroxybenzylated malonates, alkylidenebisphenols, hydroxybenzylated malonates, aromatic hydroxybenzyl compounds triazine compounds, benzylphosphonates, and acylaminophenols. Further examples of antioxidants include compounds such as, esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g., with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9- nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3- thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha- 2,6,7-trioxabicyclo[2.2.2]octane; 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}- 1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]-undecane, esters of β-(3,5-dicyclohexyl-4- hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, and esters of 3,5-di-tert-butyl-4- hydroxyphenyl acetic acid with mono- or polyhydric alcohols,

[0091] Also, antioxidants that can be used is selected from amides of β-(3,5-di-tert-butyl-4- hydroxyphenyl)propionic acid. Ascorbic acid (vitamin C) and aminic antioxidants, for example N,N′-di- isopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, N,N′-bis(1,4-dimethylpentyl)-p- phenylenediamine, N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N′-bis(1-methylheptyl)-p- phenylenediamine, N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine, N,N′- bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)- N′-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine, N-cyclohexyl-N′- phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl)diphenylamine, N,N′-dimethyl-N,N′-di-sec-butyl-p- phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine, N-phenyl-1- 17  naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, for example p,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4- butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylaminomethylphenol, 2,4′- diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, N,N,N′,N′-tetramethyl-4,4′- diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane, (o- tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl / tert-octyldiphenylamines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl / isohexyldiphenylamines, a mixture of mono- and dialkylated tert- butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- and dialkylated tert-butyl / tert-octylphenothiazines, a mixture of mono- and dialkylated tert- octylphenothiazines, N-allylphenothiazine, dinonylphenothiazine, mono-nonylphenothiazine, a mixture of mono- and dialkylated nonylphenothiazine, N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene, a mixture of one of the above disclosed unsubstituted or substituted diphenylamine with one of the above disclosed unsubstituted or substituted phenothiazine. Such compounds, when used, can be used in an amount from about 0.01 to 3 wt. % based on the total amount of adhesive in the matrix. Barrier layer

[0092] Certain embodiments of the present disclosure include a retroreflective article which comprises a barrier layer. The barrier layer independently comprises a metal oxide layer or at least one dyad. In some embodiments, the metal oxide layer comprises at least one of titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, silica aluminum oxide, or niobium oxide. In select embodiments, the metal oxide layer has a thickness of 15 to 60 nanometers (nm). The metal oxide layer has preferably a thickness of 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.

[0093] The dyad includes a (co)polymer layer and an inorganic layer overlaying the (co)polymer layer; and an outer (co)polymer layer overlaying the at least one dyad; and optionally, at least one outer inorganic layer overlaying the outer (co)polymer layer. The at least one dyad may be a single or dyad or may be a plurality of dyads, and the plurality of dyads is optionally two dyads, three dyads, four dyads, five dyads, six dyads, or even more.

[0094] In some cases, each (co)polymer layer in the at least one dyad and the outer (co)polymer layer comprises a (co)polymer selected from an olefinic (co)polymer, a (meth)acrylate (co)polymer, a urethane (co)polymer, a silicone (co)polymer, or a combination thereof.

[0095] (Co)polymeric layers can be formed from a variety of organic materials or compounds using a variety of processes. The (co)polymeric layer may be crosslinked in situ after it is applied. In one 18  embodiment, the (co)polymeric layer can be formed by flash evaporation, vapor deposition and (co)polymerization of a monomer using, for example, heat, plasma, UV radiation or an electron beam.

[0060] Exemplary monomers for use in such a method include volatilizable (meth)acrylate monomers.

[0096] In a specific embodiment, volatilizable acrylate monomers are employed. Suitable (meth)acrylates will have a molecular weight that is sufficiently low to allow flash evaporation and sufficiently high to permit condensation on the substrate. The organic materials or compounds also can be vaporized using any methods like those described below for vaporizing a metal alkoxide.

[0097] If desired, the (co)polymeric layers can alternatively 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 if desired crosslinked or (co)polymerized, (e.g., as described above. The desired chemical composition and thickness of the additional layer will depend in part on the nature of the substrate and the desired purpose of the film. Coating efficiency can be improved by cooling the substrate.

[0098] Exemplary organic compounds include esters, vinyl compounds, alcohols, carboxylic acids, acid anhydrides, acyl halides, thiols, amines and mixtures thereof. Non-limiting examples of esters include (meth)acrylates, which can be used alone or in combination with other multifunctional or monofunctional (meth)acrylates. Exemplary (meth)acrylates include hexanediol diacrylate, ethoxyethyl acrylate, phenoxyethyl acrylate, cyanoethyl (mono)acrylate, isobornyl acrylate, octadecyl acrylate, isodecyl acrylate, lauryl acrylate, beta-carboxyethyl acrylate, tetrahydrofurfuryl acrylate, dinitrile acrylate, pentafluorophenyl acrylate, nitrophenyl acrylate, 2-phenoxyethyl acrylate, 2,2,2-trifluoromethyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, polyethylene glycol diacrylate, tetraethylene glycol diacrylate, bisphenol A epoxy diacrylate, trimethylol propane triacrylate, ethoxylated trimethylol propane triacrylate, propylated trimethylol propane triacrylate, tris(2-hydroxyethyl)- isocyanurate triacrylate, pentaerythritol triacrylate, phenylthioethyl acrylate, naphthloxyethyl acrylate, IRR-214 cyclic diacrylate from UCB Chemicals, epoxy acrylate RDX80095 from Rad-Cure Corporation, the corresponding methacrylates of the acrylates listed above and mixtures thereof. Exemplary vinyl compounds include vinyl ethers, styrene, vinyl naphthylene and acrylonitrile. Exemplary alcohols include hexanediol, naphthalenediol and hydroxyethylmethacrylate. Exemplary carboxylic acids include phthalic acid and terephthalic acid, (meth)acrylic acid). Exemplary acid anhydrides include phthalic anhydride and glutaric anhydride. Exemplary acyl halides include hexanedioyl dichloride, and succinyl dichloride. Exemplary thiols include ethyleneglycol- bisthioglycolate, and phenylthioethylacrylate. Exemplary amines include ethylene diamine and hexane 1,6-diamine.

[0099] Typically, each of the inorganic layers in the at least one dyad and the optional at least one outer oxide layer overlaying the outer (co)polymer layer comprises an inorganic material selected from silicon oxide, silica 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, 19  zirconium oxynitride, hafnia, alumina, alumina doped silica, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or a combination thereof.

[0100] An outer (co)polymer layer overlays the at least one dyad which may be a plurality of dyads. The outer (co)polymer layer is preferably crosslinked.

[0101] In some exemplary embodiments, the outer (co)polymer layer comprises an olefinic (co)polymer selected from low density polyethylene, linear low density polyethylene, ethylene vinyl acetate, polyethylene methyl acrylate, polyethylene octene, polyethylene propylene, polyethylene butene, polyethylene maleic anhydride, polymethyl pentene, polyisobutene, polyisobutylene, polyethylene propylene diene, cyclic olefin (co)polymers, and blends thereof. The outer (co)polymer layer overlaying the at least one dyad may advantageously comprise at least one of an optional protective layer, a multilayer optical film, optional outer oxide layers overlaying the outer (co)polymer layer, adhesion promoting layers, a heat sealable encapsulating film, additives, or a combination thereof. Optional Protective Layers

[0102] Other functional layers or coatings can be added to the barrier layer include an optional layer or layers to make the barrier layer more rigid. The uppermost layer is optionally a suitable protective layer when the article does not include an antireflective 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 spray coating), then crosslinked using, for example, UV radiation. The optional protective layer can also be formed by flash evaporation, vapor deposition and crosslinking of a monomer as described above. Volatilizable (meth)acrylate monomers are suitable for use in such a protective layer. In a specific embodiment, volatilizable acrylate monomers are employed. Optional Multilayer Optical Films

[0103] The barrier layer and preferably the outer (co)polymer layer may optionally comprise a multilayer optical film. In general, optional multilayer optical films described herein comprise at least 3 layers (typically in a range from 3 to 2000 total layers or more). Multilayer optical films described herein can be made using general processing techniques, such as those described in U.S. Pat. No 6,783,349 (Neavin et al), the entire disclosure of which is incorporated herein by reference in its entirety.

[0104] Optional multilayer optical films described herein comprise at least a plurality of alternating first and second optical layers collectively reflecting at an incident light angle of at least one of 0°, 30°, 45°, 60°, or 75°, at least 30 (in some embodiments, at least 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or even at least 90) percent of incident infrared (IR) light (i.e., any light having a wavelength in a range from 700 nm to less than 1000 micrometers) over at least a 30-nanometer wavelength reflection bandwidth in a wavelength range from at least 100 to 350 (in some embodiments, at least 180 to 350, or even at least 200 to 350) nm. 20

[0105] In some embodiments, multilayer optical films described herein have a IR transmission band edge in a range from 10 to 90 percent transmission spanning less than 20 (in some embodiments, less than 15, or even less than 10) nanometers. Optional Outer Oxide Layers Overlaying the outer (co)polymer layer

[0106] In some exemplary embodiments, the barrier layer advantageously comprises at least one outer oxide layer, preferably a metal oxide layer, overlaying the outer (co)polymer layer. In some exemplary embodiments, the at least one outer oxide layer overlaying the outer (co)polymer layer comprises at least one layer comprised of hafnia, zirconium oxynitride, silicon oxide, gallium oxide, indium tin oxide, niobium oxide, titanium dioxide, zinc oxide, tin oxide, nickel oxide, silica alumina oxide, aluminum doped zinc oxide, or a combination thereof. In certain such embodiments, the barrier layer exhibits a static decay time, when tested according to the Static Decay Time Test, 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.

[0107] In certain exemplary embodiments, the at least one outer oxide layer advantageously comprises a plurality of outer oxide layers comprised of hafnia, zirconium oxynitride, silicon oxide, gallium oxide, indium tin oxide, tin oxide, nickel oxide, silica alumina oxide, niobium oxide, titanium dioxide, zinc oxide, aluminum doped zinc oxide, or a combination thereof and a top layer comprised of silicon oxide. In some exemplary embodiments, any of the oxide layers advantageously may be formed by hydrolysis of a metal alkoxide as described further below. Suitable metal alkoxides for forming a layer on a substrate are compounds that can be volatilized and condensed on the substrate. After condensation, the alkoxides may be cured via reaction with water to form a barrier film. Exemplary metal alkoxide compounds can have the general formula R1xM-(OR2)y-xwhere each R1is independently (C1-C20)alkyl, (C3-C8)cycloalkyl, (C2- C7)heterocycle, (C2-C7)heterocycle(C1-C8)alkylene-, (C6-C10)aryl, (C6-C10)aryl(C1-C8)alkylene-, (C5- C9)heteroaryl, or (C5-C9)heteroaryl(C1-C8)alkylene-, and each R2is independently (C1-C6)alkyl, optionally substituted with hydroxyl or oxo. The R1groups can be optionally substituted with one or more substituent groups, wherein each of the substituents are independently oxo, halo, -ORa, -SRa, cyano, nitro, trifluoromethyl, trifluoromethoxy, (C3-C8)cycloalkyl, (C2-C7)heterocycle or (C2-C7)heterocycle (C1- C8)alkylene-, (C6-C10)aryl, (C6-C10)aryl(C1-C8)alkylene-, (C5-C9)heteroaryl, (C5-C9)heteroaryl(C1- C8)alkylene-, -CCO2Ra, RaC(=O)O-, RaC(=O)-, -OCO2Ra, RbRcNC(=O)O-, RaC(=O)N(Rb)-, RbRcN-. RbRcNC(=O)-, RaC(=O)N(Rb)-, RbRcNC(=O)N(Rb)-, RbRcNC(=S)N(Rb)-, -OPO3Ra, ROC(=S)-, RaC(=S)-, -SSRa, RaS(=O)-, -NNRb, -OPO2Ra, or two R1groups can form a ring together with the atom to which they are attached. Ra, Rband Rcare each 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 Rband Rc, can form a ring together with the nitrogen atom to which they are attached. Exemplary rings include pyrrolidino, piperidino, morpholino, or thiomorpholino. Exemplary halo groups include fluoro chloro or bromo. The R1and R2alkyl groups can independently be straight or branched chains. The R1groups independently can be optionally interrupted with a hetero atom, (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 21  metal, (e.g., y can be 3 for aluminum, 4 for titanium and zirconium, and may vary depending upon the oxidation state of the metal, provided that y - x > 1, (e.g., there must be at least one alkoxy group bonded to the 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 a mixture thereof. Non-limiting examples of specific metal alkoxides include tetra(methoxy) titanate, tetra(ethoxy) titanate, tetra(isopropoxy) titanate, tetrafn- propoxy)titanate, tetra(butoxy) titanate, methyltriacetoxy silane, fluorinated silanes (e.g., such as fluorinated polyether silanes disclosed in U.S. Pat. No.6,991,826), tetra(n-propoxy) zirconate, and mixtures thereof. Additional examples include vaporizable pre(co)polymerized forms of the above metal alkoxides including dimers, trimers, and longer oligomers including polydimethoxysiloxane and polybutyl titanate. Additional metal alkoxides include methoxy, ethoxy, n-propoxy, butoxy, acetoxy, and isopropoxy functionalized metal atoms, and pre(co)polymerized forms of those metal alkoxides, including tetra(ethoxy) titanate, tetra(n- propoxy) titanate, tetra(isopropoxy) titanate, methyltriacetoxy silane, fluorinated silanes, polydimethoxy silane, and tetra(n-propoxy) zirconate.

[0108] In some embodiments, the metal alkoxide and optional organic materials or compounds, can be evaporated together to form a mixed vapor or they can be evaporated separately and mixed in the vapor phase. In applications where the alkoxide and the organic compound (or another metal alkoxide) are immiscible, it may be desirable to mix these materials in the vapor phase after separate evaporation. The alkoxide and organic compound may be condensed onto the substrate at a temperature below the condensation point of the vapor stream.

[0109] The metal alkoxides and optional organic materials or compounds can be vaporized using a variety of methods known in the art. Exemplary methods include evaporation, (e.g., flash evaporation, using techniques like those disclosed in U.S. Pat. Nos.4,954,371 and 6,045,864, sublimation, and the like. The evaporation can be conducted under vacuum or at atmospheric pressure. Carrier gas flows (optionally heated) may be added to the evaporator to reduce the partial pressure of the metal alkoxide vapor or to increase the evaporation rate. The alkoxide may be condensed onto the substrate at a temperature below the condensation point of the vapor stream.

[0110] The condensed alkoxide layer is cured by contacting the layer with water. For example, the layer can be contacted with water vapor, liquid water or a plasma containing water vapor. Curing can be enhanced with heat. Heat can be provided using any suitable source, (e.g., an infra-red heater or a catalytic combustion heater. The catalytic combustion heater can also provide water vapor. Additional energy can be provided by UV or vacuum UV light input into the condensed alkoxide layer during the curing process.

[0111] The curing reactions may be accelerated with vaporizable catalysts. Exemplary catalysts include organic acids such as acetic acid and methane sulfonic acid, photoacid generators such as triphenyl sulfonium and diphenyl iodonium compounds, or basic materials such as ammonia and photobase 22  generators. Photoactive catalysts can be activated by exposure to UV light. The catalyst can condense into the coating layer or adsorb on the surface to promote the curing reactions.

[0112] In another embodiment, a metal alkoxide and an organic compound can be vaporized, condensed on the substrate, and cured. In one embodiment, the curing can include contacting the layer with water. Curing can involve a reaction of the alkoxide with water to solidify the film layer or increase its viscosity together with (co)polymerization of the organic compound to form an intermixed layer. Curing can also be conducted in sequential steps. The components of the layer can be pre-reacted to form a volatilizable oligomer prior to deposition. Curing can also include a reaction of the components of the layer (alkoxide and organic compound) together with or without water to form an organometallic (co)polymer. The layers having the organometallic (co)polymer method may be designed to exhibit barrier properties not obtained if prepared by separate deposition and curing of the two components. Tie layer

[0113] Embodiments of the present disclosure provide a retroreflective article which includes a tie layer. The tie layer includes a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, a polyisobutylene (PIB), a polyvinyl butyrate, a butyl rubber (BR), an epoxy, a thiol / ene, or combinations thereof. Antireflective layer

[0114] Embodiments of the present disclosure provide a retroreflective article which includes an antireflective layer. The antireflective layer has a first major surface and an opposing major second surface. The second surface of the antireflective layer is attached to the structured surface of the retroreflective layer of the retroreflective article.

[0115] The antireflective layer optionally includes a porous gradient or a quarter wave antireflective layer. The antireflective layer optionally includes a structured antireflective layer having a structured first major surface. The structured first major surface has microstructures. The structured antireflective layer includes a matrix as described herein and a nanoscale dispersed phase, the structured first major surface having a micro structured surface that has a random nanostructured anisotropic surface thereon. The structured first major surface of the antireflective layer comprises a skipped tooth pattern of structures. In exemplary embodiments, the skipped tooth pattern of micro-structures further comprises nano-structures. In some embodiments, the antireflective layer further includes a fluoropolymer material.

[0116] Suitable fluoropolymers for the antireflective layer include homopolymers such as polyvinylidene difluoride and copolymers such as those derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (e.g., available from 3M Company under the trade designation 3M DYNEON THV); a copolymer of TFE, HFP, vinylidene fluoride, and perfluoropropyl vinyl ether (PPVE) (e.g., available from 3M Company under the trade designation 3M DYNEON THVP); a polyvinylidene 23  fluoride (PVDF) (e.g., 3M DYNEON PVDF 6008 from 3M Company); ethylene chlorotrifluoroethylene polymer (ECTFE) (e.g., available as HALAR 350LC ECTFE from Solvay, Brussels, Belgium); an ethylene tetrafluoroethylene copolymer (ETFE) (e.g., available as 3M DYNEON ETFE 6235 from 3M Company); perfluoroalkoxyalkane polymers (PFA); fluorinated ethylene propylene copolymer (FEP); a polytetrafluoroethylene (PTFE); copolymers of TFE, HFP, and ethylene (HTE) (e.g., available as 3M DYNEON HTE1705 from 3M Company). Combinations of fluoropolymers can also be used. In some embodiments, the fluoropolymer includes FEP. In some embodiments, the fluoropolymer includes PFA.

[0117] In some embodiments, the antireflective layer includes a porous gradient or a quarter wave antireflective layer. The antireflective layer or the dielectric reflective layer includes a quarter wave antireflective layer having a product (n»d) of the thickness (d, in nm) and the refractive index (n) which is equal to a quarter of the wavelength of the light reflected. For example, for efficiently increasing the reflectance of the light within the wavelength range of from 800 to 1200 nm, the product (n»d) of the quarter wave layer is designed to be within the range of 200 to 300 nm. Such a design can make it possible to efficiently increase the reflectance of light within a desired wavelength range (reflection wavelength range) while increasing the transmittance of light in a wavelength range(s) other than the reflection wavelength range. In one example, visible light of up to 800 nm can be reflected and infrared light over 1200 nm can be transmitted or vice versa. Such a dielectric reflective layer can be formed by known methods such as (a) a method in which a dielectric layer is formed on a transparent polymer film by multilayer coating and (b) a method in which a multilayered film is formed by coextrusion using a dielectric as a polymeric material.

[0118] Materials other than polymers may also preferably be used as the dielectric reflective layer. Exemplary non-polymeric materials include lithium fluoride (LiF), magnesium fluoride (MgF2), calcium fluoride (CaF2), barium fluoride (BaF2), lanthanum fluoride (LaF3), silicon dioxide (SiO2), aluminum dioxide (Al2O3), titanium oxide (TiO2), silicon nitride, sodium chloride (NaCl)3potassium chloride (KCl), potassium bromide (KBr), zinc sulfide (ZnS)5zirconium oxide (ZrO2) and zinc selenide (ZnSe). When non- polymeric materials are used, the dielectric reflective layer may be bound by physical or chemical deposition techniques, such as vacuum evaporation, sputtering and chemical vapor deposition (CVD), depending upon the type of dielectric reflective layer desired.

[0119] In some embodiments, the anti-reflective (AR) layers are preferably provided in the form of free- standing films, i.e., films having sufficient mechanical integrity that they can be readily handled without the need for additional reinforcing layers. The anti-reflective properties 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.

[0120] The anti-reflective layers may be used alone (such that the film forms an interface with air) or optically coupled to one or both major surfaces of a base; in the latter case, the anti-reflective layer de- reflects radiation impinging upon the surface of the base at the base / AR construction interface. The anti- reflective layers may be adhered to the surface of the base. Preferably, however, it is formed simultaneously 24  with the base by co-extrusion, as described in more detail, below. In addition, the base / anti-reflective article may itself be optically coupled, e.g., by means of an adhesive to yet another surface, e.g., a window.

[0121] The anti-reflective layer may consist of any number of polymer layers, typically ranging from one to several tens of layers. The anti-reflective polymer layers may be optically thin, e.g., with a thickness of between about 0.010 μm and about 0.25 μm or optically thick, e.g., with a thickness of greater than about 0.25 μm, or a combination of optically thin and optically thick layers. The particular thickness values are selected depending upon the portion of the electromagnetic spectrum over which the film is designed to operate and, where the anti-reflective layer is optically coupled to a base, the optical characteristics of the base. The anti-reflective polymer layers are preferably made from polymer compositions that are co- extrudable with each other and, where the anti-reflective layer is optically coupled to a base, the materials forming the base.

[0122] An anti-reflective polymer layer (which may be optically thick or thin) may be made from a thermoplastic polymer with a lower index of refraction than base. Specifically, reflection is minimized when anti-reflective layer has an index of refraction that is approximately the square root of a multiple of the index of refraction of the base and the surrounding medium (e.g., air), and is a quarter wavelength thick. Preferred polymers for anti-reflective layer typically have an index of refraction less than about 1.45, more preferably less than about 1.38.

[0123] Suitable low index polymers for anti-reflective layer include silicone polymers, methacrylate polymers, fluoropolymers, polyester copolymers, and fluoro-chloropolymers. Particularly preferred are fluoropolymers such as THV-500™ fluoropolymer (Dyneon LLC, St. Paul, Minn.), a vinylidene fluoride- tetrafluoroethylene-hexafluoropropylene terpolymer which has an index of refraction of 1.36, in the form of quarter wavelength layers on the base. These polymers can reduce the total surface reflectivity of a relatively high index of refraction base by about a factor of 2 irrespective of layer thickness. As a specific example, biaxially oriented polyethylene terephthalate (PET) has an index of refraction of 1.66 and reflectivity for visible light of 6.0% per surface at a normal angle of incidence. Covering such a biaxially oriented PET base with an optically thick layer of THV-500™ fluoropolymer will reduce the reflectivity of the combined film to a calculated value of about 3.26% per side. Reflectivity would be reduced even further if the THV layer has a quarter wavelength thickness.

[0124] To lower the reflectivity even further, it may be preferable to use a thin film, multilayer anti- reflective (AR) construction. Such constructions offer the advantage of improved broad band reduction in reflectivity relative to single-layer AR constructions while maintaining acceptable bandwidths. Each layer of the AR stack may generally be optically thin, although optically thick layers, or a combination of optically thin and optically thick layers, can be used as well.

[0125] AR stacks can consist of any number of material layers depending on the optical characteristics of the base and the desired portion of the electromagnetic spectrum over which AR stacks are designed to operate. Stacks having two or more layers can produce lower reflectivity over a wider band than a single layer, especially if the base has an index of refraction below about 1.60. With multiple layers in the AR stack, reflections from multiple interfaces can destructively interfere to reduce the overall reflectivity. 25

[0126] One of the materials in a multilayer AR stack preferably has an index equal to or higher than that of the highest index of refraction associated with the base. Since a multilayer stack of only two materials can be designed to function as an equivalent single layer of almost any index, AR stacks having four or more layers can be made using only two materials, and have a wider bandwidth than a three material, three- layer stack. This is useful in the case of articles prepared by co-extrusion (as described below) because in the co-extrusion process it is easier to add extra layers of existing materials than to add a new material. Suitable materials for the AR layers include thermoplastic polymers such as, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, 2,6-polybutylene naphthalate, polyamides, polycarbonates, atactic polystyrene, syndiotactic polystyrene, and polymethyl methacrylate. Copolymers based upon these materials may also be suitable.

[0127] Layers having different refractive indices may be separated by “tie layers” having indices intermediate those of surrounding layers. Such layers are particularly useful for improving the adhesion between layers in the stack. An example of such a construction features, in order of decreasing index of refraction, polycarbonate / polymethyl methacrylate / polyvinylidene fluoride / THV fluoropolymer, where the polymethyl methacrylate and polyvinylidene fluoride act as a tie layer to improve the adhesion between the polycarbonate and the THV fluoropolymer.

[0128] Particularly preferred articles include those in which one or more of the AR stack layers have the same material or materials as the base, or as one or more layers of the base. For example, if a multilayer base film is to be de-reflected over a portion of the wavelength spectrum, e.g., in the case of a base functioning as an IR mirror provided with an AR construction designed to de-reflect visible light, it would be desirable to design the AR stack from the same materials as the mirror itself.

[0129] Another example of a useful article is one featuring a multilayer AR construction combining both polymer layers and layers of higher index inorganic materials.

[0130] In one embodiment, the inorganic material having an index of refraction intermediate that of the base and the organic polymer may be used. For example, the inorganic material could be a sol gel-deposited layer of alumina or a zirconia-silica mix on a PEN (polyethylene naphthalate) base and the organic polymer could be a fluoropolymer such as THV-500™.

[0131] In another embodiment, the inorganic material having an index of refraction higher than that of the base may be used. For example, the inorganic material could be a sol gel-deposited layer of zirconia or titania on a PEN base and the organic polymer could be a quarter wavelength thick fluoropolymer such as THV-500™.

[0132] In another embodiment, the inorganic material could be silver, aluminum, or a quarter wavelength thick layer of a transparent conductor such as indium-tin oxide (ITO) having far IR rejection capabilities, and the polymer layer may be a quarter wavelength thick fluoropolymer such as THV-500™.

[0133] In yet another embodiment, the inorganic material could be combined with a multilayer polymer construction.

[0134] Materials useful for the base include both organic polymers and inorganic materials such as ceramics and glasses having relatively high refractive indices. Particularly preferred base materials are 26  single and multilayer polymer films. Examples of suitable single layer polymer films include polyethylene terephthalate and polycarbonate films; such films, in turn, may be uniaxially or biaxially oriented. One example of a suitable multilayer polymer film is one in which the thickness of the individual polymer layers is no greater than about 0.5 micrometers, as described in U.S. Pat. No.5,278,694 (Wheatley et al). A second example of a suitable multilayer polymer film is described in commonly assigned U.S. Pat. No.5,882,774 (Jonza et al) which details on multilayer polymer films (mirrors and polarizers) for which the Brewster angle (the angle at which reflectance goes to zero) is very large or is nonexistent for the polymer layer interfaces. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p polarized light decreases slowly with angle of incidence, is independent of angle of incidence, or increases with angle of incidence away from the normal. As a result, multilayer films having high reflectivity for both s and p polarized light over a wide bandwidth, and over a wide range of angles can be achieved.

[0135] The relationships between the indices of refraction in each film layer of the base to each other determine the reflectance behavior of the base at any angle of incidence, from any azimuthal direction. The principles and design considerations described in U.S. Pat. No. 5,882,774 (Jonza et al) can be applied to create multilayer bases having the desired optical effects for a wide variety of circumstances and applications. The indices of refraction of the layers in the multilayer base can be manipulated and tailored to produce devices having the desired optical properties. Many useful devices, such as mirrors and polarizers having a wide range of performance characteristics, can be designed and fabricated using the principles described therein.

[0136] Particularly preferred combinations of layers in the case of polarizers include polyethylene naphthalate (“PEN”) / coPEN, polyethylene terephthalate (“PET”) / coPEN, PEN / syndiotactic polystyrene (“SPS”), PET / SPS, PEN / Estar, and PET / Estar, where “coPEN” refers to a copolymer or blend based upon naphthalene dicarboxylic acid, and “Estar” is a copolymerof terephthalic acid, ethylene glycol, and cyclohexane-1,4-dimethanol that is commercially available from Eastman Chemical Co.

[0137] Particularly preferred combinations of layers in the case of mirrors include PET / Ecdel, PEN / Ecdel, PEN / SPS, PEN / THV, PEN / polymethyl methacrylate (“PMMA”), PEN / coPET, and PET / SPS, where “coPET” refers to a copolymer or blend based upon terephthalic acid (as described above), “Ecdel” is a copolymer of cyclohexane dicarboxylic acid, ethylene glycol, and cyclohexane-1,4-dimethanol that is commercially available from Eastman Chemical Co., and “THV” is a fluoropolymer commercially available from 3M Co.

[0138] The number of layers in the base is selected to achieve the desired optical properties using the minimum number of layers for reasons of film thickness, flexibility, and economy. 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.

[0139] A further criteria must be considered when designing AR constructions for non-normal incident angles with birefringent polymers such as oriented crystalline or partially crystalline polymers. In these cases, it is necessary to account for the anisotropy of the index of refraction. In other words, for non-normal angles, the reflection will depend on the index normal to the film plane as well the in-plane indices, for 27  both the substrate and the AR construction. If the two in-plane indices are different (biaxial birefringence), these differences must be taken into account for all angles of incidence.

[0140] In some embodiments, the anti-reflective layer includes a porous gradient. The anti-reflective layer may comprise acicular silica particles as described in U.S Pat. Application 12 / 187,977 (Jing et al) and the term “porous” refers to the presence of voids between the acicular silica particles created when the particles form a continuous coating. For single layer anti-reflective layer coatings, it is known that in order to maximize light transmission in air through an optically transparent substrate, and minimize reflection by the substrate, the refractive index of the coating should equal as closely as possible the square root of the refractive index of the substrate and the thickness of the coating should be one-fourth (¼) of the optical wavelength of the incident light. The voids in the layer provide a multiplicity of subwavelength interstices between the acicular silica particles where the index of refraction (RI) abruptly changes from that of air (RI=1) to that of the metal oxide particles (e.g., for silica RI=1.44). By adjusting the porosity, a coating having a calculated index of refraction (as shown in U.S. Pat. No. 4,816,333 (Lange et al.) incorporated herein by reference) very close to the square root of the refractive index of the substrate can be created. By utilizing coatings having optimal indices of refraction, at coating thicknesses equal to approximately one- fourth the optical wavelength of the incident light, the percent transmission of light through the coated substrate is maximized and reflection is minimized. Preferably, the layer has a porosity of about 25 to 65 volume percent, more preferably about 30 to 50 volume percent, when dried.

[0141] In some embodiments the porosity may be higher. Porosity may be calculated from the refractive index of the coating according to published procedures such as in W. L. Bragg, A. B. Pippard, Acta Crystallographica, volume 6, page 865 (1953) incorporated herein by reference. With acicular silica particles, this porosity provides a coating having an index of refraction of 1.15 to 1.40, preferably 1.20 to 1.36, which is approximately equal to the square root of the refractive indices of polyester, polycarbonate, or poly(methyl methacrylate) substrates. For example, a porous acicular silica particle coating having a refractive index of 1.25 to 1.36 is capable of providing a highly anti-reflective surface when coated on a polyethylene terephthalate substrate (RI=1.64) at a thickness of 1000-2000 Å. Coating layer thicknesses may be higher, as high as a few microns or mils thick, depending on the application, such as for easy-clean of removal of undesired particulates, rather than antireflection. The mechanical properties may be expected to be improved when the coating thickness is increased.

[0142] A transparent electroconductive film may be used as the antireflective layer. The films typically reflect light of wavelengths longer than a specific wavelength (this may be referred to as plasma reflection). One exemplary transparent electroconductive 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 the light within a reflection wavelength range in a predetermined ratio, and transmit, in a predetermined ratio, the light within a transmission wavelength range outside the reflection wavelength range. The reflectance of the light within the reflection wavelength range is preferably at least 40%, more preferably at least 50%, and most preferably at least 60%. 28

[0143] In some embodiments, the transparent electroconductive films are low emissivity films. In another embodiment, the film comprises: a) a first layer comprising zirconium nitride, b) a metal layer immediately adjacent the first layer comprising zirconium nitride, c) a substrate layer for the metal layer comprising a compound chosen from zirconium nitride, aluminum zinc oxide (AZO), zinc tin oxide, tin oxide, and zinc oxide, wherein the substrate layer for the metal layer is immediately adjacent the metal layer, and d) a substrate immediately adjacent the substrate layer for the metal layer; wherein the film has an emissivity of less than 0.2, a visible reflectance of less than 25%; and a visible transmission greater than 50%. In some embodiments, the substrate layer for the metal layer is a second layer comprising zirconium nitride.

[0144] In some embodiments, the film further comprises a first radiation-cured acrylate layer adjacent the first layer comprising zirconium nitride. In other embodiments, the film further comprises a first layer comprising a silicon compound adjacent the first radiation-cured acrylate layer, wherein the silicon compound is chosen from silicon aluminum oxide, silicon aluminum oxynitride; silicon oxide, silicon oxynitride, silicon nitride, silicon aluminum nitride and combinations thereof. In certain embodiments, this first layer comprising a silicon compound is the outermost layer of the film.

[0145] In other embodiments, the film further comprises a dielectric layer adjacent the substrate layer for the metal layer. In certain embodiments, the dielectric layer is a second layer comprising a silicon compound, wherein the silicon compound is chosen from silicon aluminum oxide, silicon aluminum oxynitride; silicon oxide, silicon oxynitride, silicon nitride, silicon aluminum nitride and combinations thereof.

[0146] In other embodiments, the film further comprises a second radiation-cured acrylate layer adjacent the second layer comprising a silicon compound and also adjacent to the substrate.

[0147] In other embodiments, the film further comprises a layer comprising a pressure sensitive adhesive immediately adjacent to the substrate and further comprises a liner immediately adjacent to the layer comprising a pressure sensitive adhesive.

[0148] In other embodiments, the film comprises the following layers in the recited order: a first layer comprising a silicon compound, wherein the silicon compound is chosen 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 from 1 to 615 nm; a metal layer, a second layer comprising zirconium nitride, wherein the layer has a thickness from 1 to 615 nm; a second layer comprising a silicon compound, wherein the silicon compound is chosen from silicon aluminum oxide and, silicon aluminum oxynitride, silicon oxide, silicon oxynitride silicon nitride, 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 reflectance of less than 25%; and wherein the film has a visible transmission greater than 50%. The characteristics of the different layers that can be part of the films as described in U.S Pat. Application no 15 / 566,874 (Padiyath et al) may be used. 29

[0149] In some embodiments, the antireflective layer includes a matrix as defined above and a nanoscale dispersed phase. The nanoscale dispersed phase is a discontinuous phase randomly dispersed within the matrix. The nanoscale dispersed phase can comprise nanoparticles (for example, nanospheres), nanotubes, nanofibers, caged molecules, hyperbranched molecules, micelles, reverse micelles, or the like. Preferably, the dispersed phase comprises nanoparticles or caged molecules; more preferably, the dispersed phase comprises nanoparticles.

[0150] Nanoparticles preferably have a mean diameter in the range from about 1 nm to about 100 nm. Preferably, the nanoparticles have a mean diameter of 5 nm, 20 nm, or 80 nm. Nanoparticles for the dispersed phase can comprise metals, metal oxides, carbides, nitrides, borides, halides, fluorocarbon solids, or the like, or mixtures thereof. Preferred materials include SiO2, ZrO2, TiO2, ZnO, calcium carbonate, magnesium silicate, indium tin oxide, antimony tin oxide, carbon, poly(tetrafluoroethylene), and the like. Preferably, the nanoparticles comprise SiO2.

[0151] Nanoparticles can be present in the matrix of the antireflective layer in an amount from about 1% to about 60%, or about 10% to about 40% by weight. Silicas for use in the materials of the present disclosure are commercially available from Nalco Chemical Co., Naperville, Ill. under the trade designation “Nalco Colloidal Silicas” such as products 1040, 1042, 1050, 1060, 2327 and 2329. Suitable fumed silicas include for example, products commercially available from Evonik under the trade designation, “Aerosil series OX-50”, as well as product numbers -130, -150, and -200. Other colloidal silica can be also obtained from Nissan Chemicals under the designations “IPA-ST”, “IPA-ST-L”, and “IPA-ST-ML”. Fumed silicas are also commercially available from Cabot Corp., Tuscola, Ill., under the designations “CAB-O-SPERSE 2095”, “CAB-O-SPERSE A105”, and “CAB-O-SIL M5”. Zirconias for use in composition and articles of the invention are available from Nalco Chemical Co. under the trade designation “Nalco OOSSOO8”.

[0152] Surface-treating the nano-sized particles can provide a stable dispersion in the polymeric resin. Preferably, the surface-treatment stabilizes the nanoparticles so that the particles will be well dispersed in the polymerizable resin and result in a substantially homogeneous composition. Furthermore, the nanoparticles can be modified over at least a portion of its surface with a surface treatment agent so that the stabilized particles can copolymerize or react with the polymerizable resin during curing.

[0153] The nanoparticles are preferably treated with a surface treatment agent. In general, a surface treatment agent has a first end that will attach to the particle surface (covalently, ionically or through strong physisorption) and a second end that imparts compatibility of the particle with the resin and / or reacts with 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 nature of the metal oxide surface. Silanes are preferred for silica and other siliceous fillers. Silanes and carboxylic acids are preferred for metal oxides such as zirconia. The surface modification can be done either subsequent to mixing with the monomers or after mixing. It is preferred in the case of silanes to react the silanes with the particles or nanoparticle surface before incorporation into 30  the resins. The required amount of surface modifier is dependent on several factors such as particle size, particle type, molecular weight of the modifier, and modifier type.

[0154] Representative embodiments of surface treatment agents include compounds such as, for example, isooctyl tri-methoxy-silane, N-(3-triethoxysilylpropyl)methoxyethoxy-ethoxyethyl carbamate (PEG3TES), N-(3-triethoxysilylpropyl)methoxyethoxyethoxyethyl carbamate (PEG2TES), 3- (methacryloyloxy)propyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3- (methacryloyloxy)propyltriethoxysilane, 3-(methacryloyloxy)propylmethyldimethoxysilane, 3- (acryloyloxypropyl)methyldimethoxysilane, 3-(methacryloyloxy)propyldimethylethoxysilane, vinyldimethylethoxysilane, pheyltrimethaoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, vinylmethyldiactoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris-isobutoxysilane, vinyltriisopropenoxysilane, vinyltris(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), beta- carboxyethylacrylate, 2-(2-methoxyethoxy)acetic acid, methoxyphenyl acetic acid, and mixtures thereof. Furthermore, a proprietary silane surface modifier, commercially available from OSI Specialties, Crompton South Charleston, W.V., under the trade designation “Silquest A1230” is also suitable.

[0155] The surface modification of the particles in the colloidal dispersion can be accomplished in a variety of ways. The process involves the mixture of an inorganic dispersion with surface modifying agents. Optionally, a co-solvent can be added at this point, such as for example, 1-methoxy-2-propanol, ethanol, isopropanol, ethylene glycol, N,N-dimethylacetamide and 1-methyl-2-pyrrolidinone. The co-solvent can enhance the solubility of the surface modifying agents as well as the surface modified particles. The mixture comprising the inorganic sol and surface modifying agents is subsequently reacted at room or an elevated temperature, with or without mixing. In one method, the mixture can be reacted at about 85° C. for about 24 hours, resulting in the surface modified sol. In another method, where metal oxides are surface modified the surface treatment of the metal oxide can preferably involve the adsorption of acidic molecules to the particle surface. The surface modification of the heavy metal oxide preferably takes place at room temperature.

[0156] The surface modification of ZrO2with silanes can be accomplished under acidic conditions or basic conditions. In one case the silanes can be heated under acid conditions for a suitable period of time, at which time the dispersion is combined with aqueous ammonia (or other base). This method allows the removal of the acid counter ion from the ZrO2surface as well as reaction with the silane. In another method, the particles are precipitated from the dispersion and separated from the liquid phase.

[0157] A combination of surface modifying agents can be useful, wherein at least one of the agents has a functional group co-polymerizable with a hardenable resin. For example, the polymerizing group can be ethylenically unsaturated or a cyclic function subject to ring opening polymerization. An ethylenically 31  unsaturated polymerizing group can be, for example, an acrylate or methacrylate, or vinyl group. A cyclic functional group subject to ring opening polymerization generally contains a heteroatom such as oxygen, sulfur or nitrogen, and preferably a 3-membered ring containing oxygen such as an epoxide.

[0158] Useful caged molecules for the nanodispersed phase include polyhedral oligomeric silsesquioxane molecules, which are cage-like hybrid molecules of silicone and oxygen. Polyhedral oligomeric silsesquioxane (POSS) molecules are derived from a continually evolving class of compounds closely related to silicones through both composition and a shared system of nomenclature. POSS molecules have two unique features (1) the chemical composition is a hybrid, intermediate (RSiO1.5) between that of silica (SiO2) and silicone (R2SiO), and (2) the molecules are physically large with respect to polymer dimensions and nearly equivalent in size to most polymer segments and coils. Consequently, POSS molecules can be thought of as the smallest particles (about 1-1.5 nm) of silica possible. However, unlike silica or modified clays, each POSS molecule contains covalently bonded reactive functionalities suitable for polymerization or grafting POSS monomers to polymer chains. In addition, POSS acrylate and methacrylate monomers are suitable for ultraviolet (UV) curing. High functionality POSS acrylates and methacrylates (for example, MA0735 and MA0736) are miscible with most of the UV-curable acrylic and urethane acrylic monomers or oligomers to form mechanically durable hardcoat in which POSS molecules form nano-phases uniformly dispersed in the organic coating matrix.

[0159] Carbon can also be used in the nanodispersed phase in the form of graphite, carbon nanotubes, bulky balls, or carbon black such as described in U.S. Pat. No.7,368,161 (McGurran et al.).

[0160] Additional materials that can be used in the nanodispersed phase include Irgastat™ P18 (available from Ciba Corporation, Tarrytown, N.Y.) and Ampacet LR-92967 (available from Ampacet Corporation, Tarrytown, N.Y.).

[0161] The dispersed phase is typically present in the matrix at concentrations between about 1 weight % and about 50 weight %; preferably between about 5 weight % and about 25 weight %.

[0162] In some embodiments, the structured surface of the antireflective layer of the present disclosure has a microstructured surface that has a random nanostructured anisotropic surface. The nanostructured anisotropic surface typically comprises nanofeatures having a height to width ratio of about 2:1 or greater; preferably about 5:1 or greater. In some embodiments, the height to width ratio is even 50:1 or greater, 100:1 or greater, or 200:1 or greater. The nanostructured anisotropic surface can comprise nanofeatures such as, for example, nano-pillars or nano-columns, or continuous nano-walls comprising nano-pillars or nano-columns. Preferably, the nanofeatures have steep side walls that are roughly perpendicular to the substrate. In some embodiments, the majority of the nanofeatures are capped with dispersed phase material. The concentration of the dispersed phase at the surface (versus in the interior of the matrix) can be between about 5 weight % and about 90 weight %; preferably between about 10 weight % and about 75 weight %. In some embodiments, the concentration of the dispersed phase is higher at the surface of the matrix than within the matrix. 32

[0163] In some embodiments, the matrix may comprise materials for static dissipation in order to minimize the attraction of dirt and particulate and thus maintain surface quality. Suitable materials for static dissipation include, for example, Stat-Rite™ polymers such X-5091, M-809, S-5530, S-400, S-403, and S- 680 (available from Lubrizol, Wickliffe, Ohio); 3,4-polyethylenedioxythiophene-polystyrenesulfonate (PEDOT / PSS) (available from H.C. Starck, Cincinnati, Ohio); polyaniline; polythiophene; Pelestat™ NC6321 and NC7530 antistatic additives (available from Tomen America Inc., New York, N.Y.); antistatic compositions containing at least one ionic salt consisting of a nonpolymeric nitrogen onium cation and a weakly coordinating fluororganic anion as disclosed in U.S. Pat. No. 6,372,829 and as disclosed in U.S. Pat. Application Publication 2007 / 0141329 A1.

[0164] The nanostructured surface is formed by anisotropically etching the matrix. The matrix comprising the nanoscale dispersed phase can be provided, for example, as a coating on a substrate. The substrate can be, for example, a polymeric substrate, a glass substrate or window, or a functional device such as an organic light emitting diode (OLED), a display, a photovoltaic device, or the like. The matrix comprising the dispersed phase can be coated on the substrate and cured using methods known in the art such as, for example, casting cure by casting drum, die coating, flow coating, or dip coating. The coating can be prepared in any desired thickness greater than about 1 micron or preferably greater than about 4 microns. In addition, the coating can be cured by UV, electron beam, or heat. Alternatively, the matrix comprising the dispersed phase may be the article itself.

[0165] In some embodiments, the surface of the matrix comprising the nanoscale dispersed phase may be microstructured. For example, a substrate with a v-groove microstructured surface can be coated with polymerizable matrix materials comprising a nanodispersed phase and treated by plasma etching to form nanostructures on v-groove microstructured surface. Alternatively, a microstructured article such as Fresnel lens or a microstructured article comprising microreplicated posts or columns comprising nanodispersed phases can be also treated by plasma etching to form nanostructures on microstructures. Other examples include a fine micro-structured surface resulting from controlling the solvent evaporation process from multi-solvent coating solutions, described as in U.S. Pat. No.7,378,136; or the structured surface from the micro-replication method disclosed in U.S. Pat. No.7,604,381; or any other structured surface induced by an electrical and magnetic field or other means.

[0166] The matrix is anisotropically etched using chemically reactive plasma. The RIE (reactive ion etching) process, for example, involves generating plasma under vacuum by an electromagnetic field. High energy ions from the plasma attack or etch away the matrix material as described in U.S Pat. No.9,939,557 (David et al).

[0167] The microstructures on the surface of the matrix comprising the nanoscale dispersed phase may be arranged as a series of alternating micro-peaks and micro-spaces. Micro-structures may include a series of alternating micro-peaks and micro-spaces along, or in the direction of axis, or included in, line. The direction of axis may coincide with a width dimension. Micro-spaces may each be disposed between pair of micro-peaks. In other words, plurality of micro-peaks may be separated from one another by at least one 33  micro-spaces. In at least one embodiment, at least one pair of micro-peaks may not include micro-space in- between. Patterns of alternating micro-peaks and micro-spaces may be described as "skipped tooth patterns" can be present on the structured first major surface of the antireflective layer. Each of micro-peaks and micro-spaces may include at least one straight segment or curved segment. Methods

[0168] In a second aspect, the present disclosure provides a method of conserving light in a greenhouse. The method includes attaching the retroreflective article according to any of the embodiments of the retroreflective articles 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 major surface of the retroreflective layer is positioned facing towards an interior of the greenhouse. In some embodiments, the method includes attaching the retroreflective article to the greenhouse using an adhesive. The adhesive may include a pressure sensitive adhesive or a hot melt adhesive. The method, according to certain embodiments, includes hanging the retroreflective article from a transparent roof, wall, or window. Kit

[0169] In a third aspect, the present disclosure provides a kit. The kit includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; an antireflective layer; and a light down conversion layer having a first major surface and an opposing second major surface. The retroreflective layer is according to any embodiment of retroreflective layers described above in detail with respect to the first aspect. Optionally, the kit further includes a pressure-sensitive adhesive or a hot melt adhesive. The pressure-sensitive adhesive or hot melt adhesive is useful in attaching the antireflective layer to the retroreflective layer on the outside, and in attaching the light down conversion layer either on the inside or outside. The light down conversion layer has the light conversion material as described herein. Select Embodiments of the Disclosure

[0170] Embodiment 1 is a retroreflective article. The retroreflective article includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; and a light down conversion material. The light down conversion material is present in at least one of the following: i) the retroreflective layer, ii) an optional second layer attached to the major surface of the retroreflective layer, or iii) an optional third layer attached to the optional second layer opposite the retroreflective layer.

[0171] Embodiment 2 is a retroreflective article of embodiment 1, wherein the light down conversion material comprises at least one material selected from the group consisting of a plurality of quantum dots, an optical brightener, a phosphorescent material, and combinations thereof.

[0172] Embodiment 3 is a retroreflective article of embodiment 1 or embodiment 2, wherein the light down conversion material is present in the retroreflective layer. 34

[0173] Embodiment 4 is a retroreflective article of embodiment 1, wherein the optional second layer is present, and the second layer comprises a matrix and the light down conversion material distributed in the matrix.

[0174] Embodiment 5 is a retroreflective article of embodiment 4, wherein the matrix comprises a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, a polyethylene naphthalate (PEN), a polyisobutylene (PB), a polyvinyl butyrate (PVB), a butyl rubber (BR), an epoxy, a thiol, a thiolene, or combinations thereof.

[0175] Embodiment 6 is a retroreflective article of embodiment 4 or embodiment 5, wherein the matrix of the second layer comprises an optically clear adhesive comprising at least one polyisobutylene resin and a multifunctional (meth)acrylate monomer.

[0176] Embodiment 7 is a retroreflective article of any of embodiments 4 to 6, wherein the matrix of the second layer further comprises at least one of a UV absorber, a hindered amine light stabilizer (HALS), or an antioxidant.

[0177] Embodiment 8 is a retroreflective article of embodiment 7, wherein the UV absorber includes materials that absorb light having a wavelength below 400 nm but does not emit the absorbed light in a range of from 400 nm to 1200 nm.

[0178] Embodiment 9 is a retroreflective article of any of embodiments 1 to 7, wherein the second layer comprises a first major surface and an opposing second major surface.

[0179] Embodiment 10 is a retroreflective article of any of embodiments 1 to 9, wherein the retroreflective article further comprises a barrier layer attached to at least one of the first major surface or the second major surface of the second layer.

[0180] Embodiment 11 is a retroreflective article of embodiment 10, wherein the barrier layer is disposed between the retroreflective layer and the second layer.

[0181] Embodiment 12 is a retroreflective article of embodiment 10 or embodiment 11, wherein the barrier layer is attached to the second major surface of the second layer.

[0182] Embodiment 13 is a retroreflective article of embodiment 11 or embodiment 12, wherein the optional third layer is present, the light down conversion material is present in the third layer.

[0183] Embodiment 14 is a retroreflective article of embodiment 1 or embodiment 13, wherein the third layer is the barrier layer attached to the second major surface of the second layer.

[0184] Embodiment 15 is a retroreflective article of any of embodiments 1 to 3, wherein the optional second layer is present, the second layer is a barrier layer, and the light down conversion material is present in the second layer. 35

[0185] Embodiment 16 is a retroreflective article of any of embodiments 10 to 12 or 14 to 15, wherein the barrier layer independently comprises a metal oxide layer or at least one dyad.

[0186] Embodiment 17 is a retroreflective article of embodiment 16, wherein the metal oxide layer comprises at least one of titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, silica aluminum oxide, or niobium oxide.

[0187] Embodiment 18 is a retroreflective article of embodiment 16 or embodiment 17, wherein the metal oxide layer has a thickness of 15 to 60 nanometers (nm).

[0188] Embodiment 19 is a retroreflective article of embodiment 16, wherein the at least one dyad is comprised of a (co)polymer layer and an inorganic layer overlaying the (co)polymer layer; and an outer (co)polymer layer overlaying the at least one dyad. The dyad includes optionally at least one outer inorganic layer overlaying the outer (co)polymer layer.

[0189] Embodiment 20 is a retroreflective article of embodiment 16 or embodiment 19, wherein the at least one dyad is a plurality of dyads. The plurality of dyads is optionally two dyads, three dyads, four dyads, five dyads, or six dyads.

[0190] Embodiment 21 is a retroreflective article of embodiment 19 or embodiment 20, wherein the inorganic layer is formed of an inorganic material. The inorganic material is selected from silicon oxide, silica 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, hafnia, aluminum oxide, alumina doped silicon oxide, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or combinations thereof.

[0191] Embodiment 22 is a retroreflective article of any of embodiments 19 to 21, wherein each (co)polymer layer in the at least one dyad includes a (co)polymer selected from an olefinic (co)polymer, a (meth)acrylate (co)polymer, a urethane (co)polymer, a silicone (co)polymer, or a combination thereof.

[0192] Embodiment 23 is a retroreflective article of any of embodiments 1 to 22, wherein the optional second layer is present, and the second layer is a tie layer, and wherein the optional third layer is present, and wherein the light down conversion material is present in the third layer.

[0193] Embodiment 24 is a retroreflective article of any of embodiments 1 or 23, wherein the optional third layer is present, and the light down conversion material is present in the third layer.

[0194] Embodiment 25 is a retroreflective article of embodiment 24, wherein the third layer comprises a matrix and the light down conversion material distributed in the matrix. The matrix includes a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic 36  olefin polymer, a polycarbonate, a polyethylene naphthalate (PEN), a polyisobutylene (PB), a polyvinyl butyrate (PVB), a butyl rubber (BR), an epoxy, a thiol, a thiolene, or combinations thereof.

[0195] Embodiment 26 is a retroreflective article of any of embodiments 1 to 25, wherein the light down conversion material comprises a plurality of quantum dots.

[0196] Embodiment 27 is a retroreflective article of any of embodiments 1 to 26, wherein the light down conversion material comprises an optical brightener.

[0197] Embodiment 28 is a retroreflective article of any of embodiments 1 to 27, wherein the light down conversion material comprises a phosphorescent material.

[0198] Embodiment 29 is a retroreflective article of any of embodiments 1 to 28, wherein the retroreflective article further includes an antireflective layer having a first major surface and an opposing second major surface. The second major surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

[0199] Embodiment 30 is a retroreflective article of embodiment 29, wherein the antireflective layer includes a porous gradient or a quarter wave antireflective layer.

[0200] Embodiment 31 is a retroreflective article of embodiment 29 or embodiment 30, wherein the antireflective layer includes a structured antireflective layer having a structured first major surface.

[0201] Embodiment 32 is a retroreflective article of embodiment 31, wherein the structured first major surface of the antireflective layer comprises microstructures.

[0202] Embodiment 33 is a retroreflective article of embodiment 31 or embodiment 32, wherein the structured antireflective layer comprises a matrix and a nanoscale dispersed phase. The structured first major surface includes a microstructured surface that has a random nanostructured anisotropic surface thereon.

[0203] Embodiment 34 is a retroreflective article of embodiment 31 or embodiment 32, wherein the structured first major surface of the antireflective layer comprises a skipped tooth pattern of structures.

[0204] Embodiment 35 is a retroreflective article of any of embodiments 29 to 34, wherein the antireflective layer includes a fluoropolymer material.

[0205] Embodiment 36 is a retroreflective article of any of embodiments 1 to 35, wherein the surface structure elements of the retroreflective layer comprise at least one shape having a cross section, in a plane parallel to the opposing major surface of the retroreflective layer, selected from the group consisting of ellipsoidal, semicircular, oblong, and polygonal.

[0206] Embodiment 37 is a retroreflective article of any of embodiments 1 to 36, wherein the surface structure elements of the retroreflective layer comprise at least one shape selected from the group consisting of a cube corner, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cube corner. 37

[0207] Embodiment 38 is a method of conserving light in a greenhouse. The method includes attaching the retroreflective article of any of embodiments 1 to 37, to at least one of a transparent roof, wall, or window of the greenhouse. The retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the greenhouse.

[0208] Embodiment 39 is a method of conserving light in a building having windows or skylights. The method includes attaching the retroreflective article of any of embodiments 1 to 37, to at least one of a window or skylight of the building. The retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the building.

[0209] Embodiment 40 is a method of embodiment 38 or embodiment 39, wherein the retroreflective article is attached via an adhesive.

[0210] Embodiment 41 is a method of embodiment 40, wherein the adhesive is a pressure sensitive adhesive or a hot melt adhesive.

[0211] Embodiment 42 is a method of any of embodiments 38 to 41, wherein the retroreflective article is hung from the transparent roof, wall, window, or skylight.

[0212] Embodiment 43 is a method of any of embodiments 38 to 42, wherein the retroreflective article of embodiments 1 to 37 includes an optional antireflective layer on outer surface, and light down conversion layer either inside or outside, is attached to interior of the greenhouse or the building with pressure sensitive adhesive or hotmelt adhesive.

[0213] Embodiment 44 is a kit. The kit includes a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; an antireflective layer; and a light down conversion layer having a first major surface and an opposing second major surface.

[0214] Embodiment 45 is a kit of embodiment 44, wherein the kit includes a pressure-sensitive adhesive or a hot melt adhesive.

[0215] The articles, kits and methods disclosed herein have frequently been described herein in reference to their use in agricultural applications in general, and in greenhouses in particular. However, one skilled in the art will appreciate that these articles, kits and methods may be employed in various other applications as well including, for example, general indoor lighting applications. EXAMPLES Reflectance and Transmittance Colorimetry Test

[0216] Reflectance and transmittance colorimetry measurements were made with a Lambda 1050 UV / Vis / NIR spectrophotometer (Perkin Elmer, Shelton, CT) according to ASTM E308-22. The spectrophotometer was equipped with a 150 mm InGaAs integration sphere for transmittance and reflectance and a USRS-99-020 reflectance standard (Labsphere, North Sutton, NH), in place when in transmittance mode. Data was collected from 780 nm and 380 nm using a D65 Tungsten lamp (daylight 38  with a color temperature of 6500K). The spectrum was interpolated to 5 nm intervals, and the color parameters were calculated using standard CIE tables between 380 nm and 780 nm. Tristimulus values (X, Y, and Z) were calculated then normalized to give (x, y, and z, where x + y + z = 1). The x, y, and z values are converted to give L*, a*, and b* coordinates. L* represents black and white values from 0-100, a* represents the green and magenta color coordinate with negative values more green and positive values more magenta, and b* represents the blue and yellow color coordinate with negative values more blue and positive values more yellow. A thickness correction was not used for the transmittance measurements.

[0217] Measurement steps included (1) calibration of the system using the reflectance standard, (2) placing the sample into the transmittance holder with reflectance standard still in place or placing the sample in the reflectance position without the reflectance standard, (3) initiating the measurement via the instrument’s software, (4) recording the data as % light transmitted or reflected vs wavelength in nanometers (nm) and conversion to L*a*b* values as described above. Samples were measured via transmittance through the top and reflectance from the bottom as constructed, described below. Prototype Light Conversion and Conservation Films

[0218] Light conversion and conservation films used to make spectrophotometry and colorimetry measurements were made by lamination into a sandwich structure with one or more layers in the following layer order from top to bottom: (1) Surface structured film (SSF) (i.e., an anti-reflective film), (2) Light conservation and redirection film (LRF) (i.e., a retroreflective film), (3) Optically clear adhesive (OCA), and (4) Light conversion film (LCF). Layers (1) and (2) were bonded with 3M Scotch Super Glue (3M Company, St. Paul, MN) in a manner such that the glue did not interfere with the optical path used for testing. Dots of glue were applied outside the testing area to hold the two films together. Layers (2) and (4) were held together by layer (3), which itself was an optically clear adhesive.

[0219] The surface structured film (SSF) (1) was prepared as described in in WO 2019 / 130198 A1, Prophetic Example 1, the disclosure of which is incorporated herein by reference in its entirety. The light conservation / redirection film (LRF) (2) was prepared as described in US 11567239 B2, Example 9, the disclosure of which is incorporated herein by reference in its entirety. The optically clear adhesive (OCA) (3) was obtained under the trade designation “3M Optically Clear Adhesive 8211” from 3M Company, St. Paul, MN. The light conversion film (LCF) (4) was prepared as described in US 10316245 B2, Example 1, Solution B, and coated between layers of 5 mil thick PET barrier film, the disclosure of which is incorporated herein by reference in its entirety. Examples

[0220] Example 1 was prepared by laminating from top to bottom an LRF, OCA, and LCF into a sandwich structure. The LRF was placed with the retroreflective surface face-down towards the LCF.

[0221] Example 2 was prepared as in Example 1 with an additional layer of SSF on top, having its surface structure face-up away from the LCF. The SSF was bonded to the LRF with several dots of 3M Scotch Super Glue to secure the films together, but as to not obstruct the testing area. 39  Comparative Examples

[0222] Comparative Example 1 was solely the LCF, both sides were the same.

[0223] Comparative Example 2 was solely the LRF, with the retroreflective surface face-down.

[0224] Comparative Example 3 was solely the SSF, with the anti-reflective surface structures face-up.

[0225] Light conversion and conservation films of Examples 1-2 and Comparative Examples 1-3 were tested using the procedures described above, with testing directions from top or bottom with respect to the surface the source light impinges on first in accordance with layer structure as described above. Results are reported in Table 1. Table 1 Sample Test Direction L* a* b* Transmission 83.21 -0.1 4.56 through Top Example 1 LRF-OCA-LCF Reflection from 69.58- 14.52 Bottom Transmission0.24 5.08 SSF-LRF-OCA- through Top Example 2 LCF Reflection from 80.68 -4.48 19.91 BottomTransmission 85.12 0.24 4.66 Comparative through Top LCF Example 1 Reflection from 63.46 -4.63 13.11Bottom Transmission throu 91.6 -0.14 -3.1 Comparative gh Top LRF Example 2 Reflection from 59.94 -1.36 -1.95 Bottom Transmission95.4 0.73 0.79 Comparative through Top SSF Example 3Reflection from 45 -9.95 1.48 BottomResults

[0226] Higher values of L* in transmission are typically associated with higher transmission of light but are not corrected for thickness here so do not directly represent transmittivity. Thicker samples typically transmit less light. Surface structures like those on the SSF and LRF can improve transmittivity by reducing glare or surface reflection from the structured surface. 40

[0227] As a* measures more negative, it indicates the white light impinging on the sample is filtered to let green light through or is converted in wavelength to appear more green (as the quantum dots in the LCF are designed).

[0228] Likewise, as b* values are more positive, it indicates the white light impinging on the sample is filtered to let yellow light through or is converted to appear more yellow (also how the quantum dots in the LCF are designed). In reflection, L* is less affected by thickness, thus it more closely represents how reflective a sample is. Prophetic Examples

[0229] Prophetic Example 1 is made in the same manner as Example 1, except that the LRF contains no UV absorber.

[0230] Prophetic Example 2 is made in the same manner as Example 2, except that the LRF contains no UV absorber.

[0231] Prophetic Example 3 is made by laminating from top to bottom an LCF, OCA, LRF into a sandwich structure. The LRF is placed with the retroreflective surface face-down away from the LCF.

[0232] Prophetic Example 4 is made in the same manner as Prophetic Example 3 with an additional layer of SSF on top, having its surface structure face-up away from the LCF. The LCF is bonded to the LRF with several dots of 3M Scotch Super Glue to secure the films together, but as to not obstruct the testing area.

[0233] The above description of the present invention is illustrative and is not intended to be limiting. It will thus be appreciated that various additions, substitutions, and modifications may be made to the above described embodiments without departing from the scope of the present invention. Accordingly, the scope of the present invention should be construed in reference to the appended claims.

[0234] Moreover, it is specifically contemplated that the features described in the appended claims may be arranged in different combinations or sub-combinations without departing from the scope of the present disclosure. For example, it is contemplated that features set forth in two or more claims may be combined into a single claim without departing from the scope of the present disclosure, whether or not the resulting combination of features is explicitly disclosed elsewhere in the appended claims or disclosure. 41

Claims

What is claimed is:

1. A retroreflective article comprising: a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; and a light down conversion material, wherein the light down conversion material is present in at least one of the following: i) the retroreflective layer, ii) an optional second layer attached to the major surface of the retroreflective layer, or iii) an optional third layer attached to the optional second layer opposite the retroreflective layer.

2. The retroreflective article of claim 1, wherein the light down conversion material comprises at least one material selected from the group consisting of a plurality of quantum dots, an optical brightener, a phosphorescent material, and combinations thereof.

3. The retroreflective article of claim 1 or claim 2, wherein the light down conversion material is present in the retroreflective layer.

4. The retroreflective article of claim 1, wherein the optional second layer is present, and wherein the second layer comprises a matrix and the light down conversion material is distributed in the matrix.

5. The retroreflective article of claim 4, wherein the matrix comprises a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, a polyethylene naphthalate (PEN), a polyisobutylene (PB), a polyvinyl butyrate (PVB), a butyl rubber (BR), an epoxy, a thiol, a thiolene, or combinations thereof.

6. The retroreflective article of claim 4 or claim 5, wherein the matrix of the second layer comprises an optically clear adhesive comprising at least one polyisobutylene resin and a multifunctional (meth)acrylate monomer.

7. The retroreflective article of any of claims 4 to 6, wherein the matrix of the second layer further comprises at least one of a UV absorber, a hindered amine light stabilizer (HALS), or an antioxidant.

8. The retroreflective article of any of claims 4 to 7, wherein the second layer comprises a first major surface and an opposing second major surface, wherein the retroreflective article further comprises a barrier layer attached to at least one of the first major surface or the second major surface of the second layer.

9. The retroreflective article of claim 8, wherein the barrier layer is disposed between the retroreflective layer and the second layer. 42  10. The retroreflective article of claim 8, wherein the barrier layer is attached to the second major surface of the second layer.

11. The retroreflective article of claim 8, wherein the barrier layer is attached to each of the first major surface and the second major surface of the second layer.

12. The retroreflective article of claim 10 or claim 11, wherein the optional third layer is present, the light down conversion material is present in the third layer, and the third layer is the barrier layer attached to the second major surface of the second layer.

13. The retroreflective article of any of claims 1 to 3, wherein the optional second layer is present, wherein the second layer is a barrier layer, and wherein the light down conversion material is present in the second layer.

14. The retroreflective article of any of claims 8 to 13, wherein the barrier layer independently comprises a metal oxide layer or at least one dyad.

15. The retroreflective article of claim 14, wherein the metal oxide layer comprises at least one of titanium oxide, aluminum oxide, zinc oxide, tantalum pentoxide, zirconium oxide, silicon oxide, silica aluminum oxide, or niobium oxide.

16. The retroreflective article of claim 14 or claim 15, wherein the metal oxide layer has a thickness of 15 to 60 nanometers (nm).

17. The retroreflective article of claim 14, wherein the at least one dyad is comprised of a (co)polymer layer and an inorganic layer overlaying the (co)polymer layer; and an outer (co)polymer layer overlaying the at least one dyad; and optionally, at least one outer inorganic layer overlaying the outer (co)polymer layer.

18. The retroreflective article of claim 17, wherein the at least one dyad is a plurality of dyads, optionally wherein the plurality of dyads is two dyads, three dyads, four dyads, five dyads, or six dyads.

19. The retroreflective article of claim 17 or claim 18, wherein the inorganic layer is formed of an inorganic material selected from silicon oxide, silica 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, hafnia, aluminum oxide, alumina doped silicon oxide, lanthanum fluoride, neodymium fluoride, aluminum fluoride, magnesium fluoride, calcium fluoride, or combinations thereof.

20. The retroreflective article of any of claims 17 to 19, wherein each (co)polymer layer in the at least one dyad comprises a (co)polymer selected from an olefinic (co)polymer, a (meth)acrylate (co)polymer, a urethane (co)polymer, a silicone (co)polymer, or a combination thereof.

21. The retroreflective article of any of claims 1 to 20, wherein the optional second layer is present, wherein the second layer is a tie layer, wherein the optional third layer is present, and wherein the light down conversion material is present in the third layer.

22. The retroreflective article of claim 21, wherein the third layer comprises a matrix and the light down conversion material distributed in the matrix, and the matrix comprises a polyethylene terephthalate (PET), a crosslinked polysiloxane, a silicone thermoplastic polymer, a crosslinked urethane, a thermoplastic urethane, a crosslinked (meth)acrylate, a polymethyl methacrylate (PMMA), a copolymer of ethyl acrylate and methyl methacrylate (coPMMA), a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, a polyethylene naphthalate (PEN), a polyisobutylene (PB), a polyvinyl butyrate (PVB), a butyl rubber (BR), an epoxy, a thiol / ene, or combinations thereof.

23. The retroreflective article of any of claims 1 to 22, wherein the light down conversion material comprises a plurality of quantum dots.

24. The retroreflective article of any of claims 1 to 23, wherein the light down conversion material comprises an optical brightener.

25. The retroreflective article of any of claims 1 to 24, wherein the light down conversion material comprises a phosphorescent material.

26. The retroreflective article of any of claims 1 to 25, further comprising an antireflective layer having a first major surface and an opposing second major surface, wherein the second major surface of the antireflective layer is attached to the structured surface of the retroreflective layer.

27. The retroreflective article of claim 26, wherein the antireflective layer comprises a porous gradient or a quarter wave antireflective layer.

28. The retroreflective article of claim 26 or claim 27, wherein the antireflective layer comprises a structured antireflective layer having a structured first major surface.

29. The retroreflective article of claim 28, wherein the structured first major surface of the antireflective layer comprises microstructures.

30. The retroreflective article of claim 28 or claim 29, wherein the structured antireflective layer comprises a matrix and a nanoscale dispersed phase, the structured first major surface having a microstructured surface that has a random nanostructured anisotropic surface thereon.

31. The retroreflective article of claim 28 or claim 29, wherein the structured first major surface of the antireflective layer comprises a skipped tooth pattern of structures.

32. The retroreflective article of any of claims 26 to 31, wherein the antireflective layer comprises a fluoropolymer material.

33. The retroreflective article of any of claims 1 to 32, wherein the surface structure elements of the retroreflective layer comprise at least one shape having a cross section, in a plane parallel to the opposing major surface of the retroreflective layer, selected from the group consisting of ellipsoidal, semicircular, oblong, and polygonal.

34. The retroreflective article of any of claims 1 to 33, wherein the surface structure elements of the retroreflective layer comprise at least one shape selected from the group consisting of a cube corner, a hemisphere, a quarter sphere, a prism, a pyramid, and a truncated cube corner.

35. A method of conserving light in a greenhouse, the method comprising: attaching the retroreflective article of any of claims 1 to 34 to at least one of a transparent roof, wall, or window of the greenhouse, wherein the retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the greenhouse.

36. A method of conserving light in a building having windows or skylights, the method comprising: attaching the retroreflective article of any of claims 1 to 34 to at least one of a window or skylight of the building, wherein the retroreflective article is oriented such that the major surface of the retroreflective layer is positioned facing towards an interior of the building.

37. The method of claim 35, wherein the retroreflective article is attached via an adhesive.

38. The method of claim 35, wherein the retroreflective article is hung from the transparent roof, wall, or window.

39. A kit comprising: a retroreflective layer comprising a plurality of surface structure elements that collectively form a structured surface that is opposite a major surface; an antireflective layer; and a light down conversion layer having a first major surface and an opposing second major surface.

40. The kit of claim 38, further comprising a pressure-sensitive adhesive or a hot melt adhesive.

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