Structured transfer articles and articles and methods of making structured articles

Abstract

Structured transfer articles and articles are provided. A transfer article includes a microstructured film that includes microstructures protruding therefrom. The transfer article further includes: a metal or doped semiconductor release layer on the microstructure; a (co) polymer layer located on the release layer opposite the microstructured film; and optionally a multilayer optical film on the (co) polymer layer opposite the release layer. The multi-layer optical film includes one or more alternating first and second inorganic optical layers that collectively reflect and absorb light that is normally incident on the first major surface of the microstructured film, at least 50% of the incident ultraviolet light is averagely reflected and absorbed over a wavelength reflection bandwidth of at least 30 nm in a wavelength range of 190 nm (nm) to 400 nm. An article includes at least: a microstructured film; the multi-layer optical film is positioned on the microstructure; and a (co) polymer layer disposed on a major surface of the multilayer optical film opposite the microstructured film. Also provided is a method of manufacturing an article, the method comprising: obtaining a transfer article; depositing a polymeric material or a crosslinkable material on the outer surface of the transfer article; curing the material; and removing the stripping layer.

Description

Background Art

[0001] There is a class of telecommunications networks that have infrastructure provided by constellations of thousands of small satellites deployed in low Earth orbit. These satellites need to be powered by solar arrays mounted on their frames, and these solar arrays need to be protected from the harsh environment of low Earth orbit.

[0002] Equipment typically operates at altitudes ranging from 20 km to 2000 km, where the thin atmosphere absorbs little solar radiation. Consequently, high-altitude installations are exposed to a more intense AM0 solar spectrum and higher-intensity ultraviolet (UV) radiation, particularly UV-C radiation, than radiation present in the AM1.5 solar spectrum encountered at Earth's surface. Summary of the Invention

[0003] In a first aspect, a transfer article is provided. The transfer article comprises a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The transfer article further comprises: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on a major surface of the release layer opposite the microstructured film; and a multilayer optical film disposed on a major surface of the (co)polymer layer opposite the release layer. The multilayer optical film is composed of one or more alternating first and second inorganic optical layers, which together reflect and absorb light normally incident on the first major surface of the microstructured film, and reflect and absorb an average of at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0004] In a second aspect, another transfer article is provided. The transfer article comprises a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The transfer article further comprises: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; and a (co)polymer layer disposed on a major surface of the release layer opposite the microstructured film, wherein the (co)polymer layer optionally further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

[0005] In a third aspect, an article is provided. The article comprises a first microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the first microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The article further comprises: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on a major surface of the release layer opposite to the first microstructured film; a multilayer optical film disposed on a major surface of the (co)polymer layer opposite to the release layer; and a second microstructured film adjacent to a major surface of the multilayer optical film opposite to the (co)polymer layer. The second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure. The multilayer optical film comprises one or more alternating first and second inorganic optical layers, the one or more alternating first and second inorganic optical layers collectively reflecting and absorbing light normally incident on the first major surface of the second microstructured film, at least 50%, 60%, 70%, 80%, 90%, or 95% of incident ultraviolet light within a wavelength reflection bandwidth of at least 30 nm within a wavelength range of 190 nanometers (nm) to 400 nm, on average.

[0006] In a fourth aspect, another article is provided. The article includes a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The article also includes a multilayer optical film disposed on the plurality of microstructures and a (co)polymer layer disposed on a major surface of the multilayer optical film opposite the microstructured film. The multilayer optical film is comprised of one or more alternating first and second inorganic optical layers, the one or more alternating first and second inorganic optical layers collectively reflecting and absorbing light normally incident on the first major surface of the microstructured film to an average of at least 50%, 60%, 70%, 80%, 90%, or 95% of incident ultraviolet light within a wavelength reflection bandwidth of at least 30 nm within a wavelength range of 190 nanometers (nm) to 400 nm.

[0007] In a fifth aspect, a method of making an article is provided. The method comprises: obtaining a transfer article according to the first or second aspect; depositing a polymeric material or a cross-linkable material on an outer major surface of the transfer article opposite the first microstructured film; curing the polymeric material or the cross-linkable material to form a second microstructured film; and removing the release layer from the transfer article. The second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface with a slope such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure, and wherein the first major surface of the second microstructured film is adjacent to the multilayer optical film.

[0008] Broadband UV protection is of particular interest. Alternating layers of high- and low-refractive-index materials have been shown to provide UV blocking, but these are typically limited to relatively narrow reflection bands. UV absorbers, on the other hand, often fail to provide sufficient absorption without thick layers, and many solutions are made with organic absorbers, which don't always withstand the higher-energy UVC light and atomic oxygen present in low-Earth orbit.

[0009] Sometimes, a substrate that is preferred for vapor deposition of a layer of material that provides UV shielding properties is not preferred for use in a space environment due to limitations in material properties, such as thermal expansion coefficient or radiation durability. Being able to separate the material properties of the substrate to be used in a space environment from the substrate used to make the article (e.g., using vapor coating deposition) would allow for a higher combination of performance and durability.

[0010] Transfer articles and articles according to at least certain embodiments of the present disclosure provide an inorganic-based solution that combines the UV absorption of inorganic materials (e.g., titanium oxide or niobium oxide) with reflection bands created by alternating high and low refractive index materials. This creates a broadband UV blocking filter that is tolerant to both UV and atomic oxygen. This technology can potentially replace the existing protection solution for solar cells in space, namely cover glass. The use of cover glass is costly due to the fragile nature of glass slides and the small size of the glass slides, which requires extensive trimming / lamination.

[0011] Various unexpected results and advantages are obtained in exemplary embodiments of the present disclosure. One such advantage of exemplary embodiments of the present disclosure is that the combination of UV absorption and reflection in the structured article results in a broadband UV blocking filter made of a durable inorganic material that can withstand low earth orbit conditions. Additionally, the use of microstructured films improves light capture of the article by minimizing light losses due to reflection compared to flat films. Furthermore, it has been found that the microstructured article can be transferred to different microstructured substrates. The UV shielding layer can be sputter deposited or evaporated in a roll-to-roll process. Therefore, another advantage of the exemplary embodiments is that a high speed roll-to-roll continuous production process for the structured transfer articles and structured articles of the present disclosure can be achieved.

[0012] The various aspects and advantages of the exemplary embodiments of the present disclosure have been summarized. The above summary of the invention is not intended to describe each illustrated embodiment or every implementation of the present certain exemplary embodiments of the present disclosure. The following drawings and detailed description more particularly illustrate certain preferred embodiments using the principles disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present disclosure may be more fully understood upon consideration of the following detailed description of various embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0014] Figure 1A is a perspective view of a Cartesian coordinate system that can be used to describe various microstructured surfaces;

[0015] Figure 1B is a schematic cross-sectional view of a microstructured film for use in exemplary transfer articles and articles disclosed herein;

[0016] Figure 1C is a schematic cross-sectional view of an exemplary structured transfer article according to various exemplary embodiments disclosed herein;

[0017] Figure 1Dis a schematic cross-sectional view of an exemplary structured article according to various exemplary embodiments disclosed herein;

[0018] Figure 2 are schematic cross-sectional views of exemplary structured transfer articles 10 and 20 and exemplary articles 30 and 40 according to various exemplary embodiments disclosed herein;

[0019] Figure 3 is a perspective view of a microstructured surface comprising an array of linear prisms;

[0020] Figure 4A is a perspective view of a microstructured surface comprising an array of cube corner elements;

[0021] Figure 4B is a perspective view of a microstructured surface comprising an array of pyramidal elements;

[0022] Figure 5 is a perspective view of a microstructured surface including an array of cones;

[0023] Figure 6 is a perspective view of a microstructured surface including a diffraction grating with an offset angle.

[0024] Figure 7 is a perspective view of a microstructured surface comprising an array of inverted pyramids.

[0025] Figure 8 is a scanning electron microscope (SEM) image of a microstructured surface including an array of inverted cones.

[0026] In the accompanying drawings, like reference numerals indicate like elements. Although the above drawings, which may not be drawn to scale, illustrate various embodiments of the present disclosure, other embodiments are also contemplated, as indicated in the detailed description. In all cases, the present disclosure describes the present disclosure in terms of representations of exemplary embodiments, rather than by way of express limitation. It should be understood that those skilled in the art will be able to devise numerous other modifications and embodiments that fall within the scope and spirit of the present disclosure. DETAILED DESCRIPTION

[0027] For the following glossary of defined terms, these definitions shall govern throughout this application, unless a different definition is provided in the claims or elsewhere in the specification.

[0028] Glossary

[0029] Certain terms are used throughout the specification and claims, which, although largely well known, may require some explanation. It should be understood that:

[0030] The term "fluoropolymer" refers to any organic polymer containing fluorine.

[0031] The term "non-fluorinated" means not containing fluorine.

[0032] The term "(co)polymer" includes homo(co)polymers and (co)polymers, as well as homo(co)polymers or (co)polymers that can be formed in a miscible blend (e.g., by coextrusion or by reactions including, for example, transesterification). The term "(co)polymer" includes random (co)polymers, block (co)polymers and star (co)polymers.

[0033] As used herein, "adjacent" includes both direct contact (eg, directly adjacent) and the presence of one or more intervening layers between the adjacent materials.

[0034] As used herein, "incident" with respect to light refers to light that falls on or impinges on a material.

[0035] The term "crosslinked" (co)polymer refers to a (co)polymer whose (co)polymer chains are joined together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network of (co)polymers. Typically, crosslinked (co)polymers are characterized by their insolubility but can be swellable in the presence of a suitable solvent.

[0036] The term "curing" encompasses cooling and / or hardening as well as processes that cause chemical changes, such as cross-linking or reactions that create covalent bonds to harden the multilayer film layers or increase their viscosity.

[0037] The term "cured (co)polymer" includes both cross-linked (co)polymers and uncross-linked (co)polymers.

[0038] The term "metal" includes pure metals or metal alloys.

[0039] The term "film" or "layer" refers to an individual layer within a multilayer film.

[0040] The term "substrate" encompasses films and layers, including microstructured films / layers.

[0041] The term "(meth)acryloyl" 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 and acrylic acid or methacrylic acid.

[0042] The term "optically clear" refers to an article that exhibits no visually observable distortion, haze, or defects when inspected by the unaided eye at a distance of about 1 meter, preferably at a distance of about 0.5 meters.

[0043] The term "optical thickness," when used with respect to a layer, refers to the physical thickness of the layer multiplied by its planar refractive index.

[0044] The term "vapor coating" or "vapor deposition" refers to applying a coating to a substrate surface from the vapor phase, for example, by evaporating and subsequently depositing a precursor material of the coating or the coating material itself onto the substrate surface. Exemplary vapor coating processes include, for example, physical vapor deposition (PVD), chemical vapor deposition (CVD), and combinations thereof.

[0045] By using directional terms such as "atop," "on," "over," "overlying," "uppermost," "under," and the like, with respect to the positions of various elements in the disclosed coated articles, we refer to the relative positions of the elements with respect to a horizontally disposed, upwardly facing substrate. However, unless otherwise indicated, the present invention is not intended to have any particular spatial orientation of the substrate or article during or after manufacture, or when interpreting the claims.

[0046] As used herein, unless otherwise indicated, "radiation" refers to electromagnetic radiation.

[0047] As used herein, "scattering" relative to the wavelength of light refers to causing the light to deviate from a straight path and travel in different directions with different intensities.

[0048] As used herein, "reflectivity" is a measure of the proportion of light or other radiation that strikes a surface at normal incidence and is reflected by it. Reflectivity typically varies with wavelength and is reported as the percentage of incident light that is reflected from the surface (0% - no light reflected, 100 - all light reflected). Reflectivity and reflectance are used interchangeably herein.

[0049] As used herein, "reflection" and "reflectivity" refer to the property of reflecting light or radiation, particularly reflectivity measured independently of the thickness of the material.

[0050] As used herein, "average reflectance" refers to the reflectance averaged over a specified wavelength range.

[0051] As used herein, "absorbent" refers to a material that converts light radiation energy into internal energy.

[0052] As used herein, "absorption" relative to the wavelength of light includes both absorption and scattering, since scattered light is ultimately absorbed. Absorbance can be measured using the method described in ASTM E903-12, "Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres." Absorbance measurements described herein are performed by measuring transmittance as described above and then calculating absorptance using Formula 1.

[0053] As used herein, the term "absorbance," relative to a quantitative measurement, refers to the base-10 logarithm of the ratio of incident radiation power to the transmitted radiation power through a material. This ratio can be described as the radiant flux received by a material divided by the radiant flux transmitted by the material. Absorbance (A) can be calculated based on internal transmittance (T) according to the following formula 1:

[0054] A = -log 10 T (1)

[0055] Emissivity can be measured using an infrared imaging radiometer using the method described in ASTM E1933-14 (2018), "Standard Practice for Measuring and Compensating for Emissivity Using Infrared Imaging Radiometers." Absorbance is related to emissivity according to Kirchhoff's law of thermal radiation. Absorbance, absorptivity, emissivity, and emissivity are used interchangeably herein for the same purpose of transmitting infrared energy into the atmosphere. Absorption and emission are also used interchangeably herein.

[0056] As used herein, the terms "transmittance" and "transmittance" refer to the ratio of the total transmittance of a layer of material compared to the total transmittance received by the material, which accounts for the effects of absorption, scattering, reflection, etc. Transmittance (T) can range from 0 to 1 or be expressed as a percentage (T%).

[0057] As used herein, "transparent" refers to a material (eg, a film or layer) that absorbs less than 20% of light having wavelengths between 350 nm and 2500 nm.

[0058] As used herein, "bandwidth" refers to the width of a continuous band of wavelengths.

[0059] As used herein, the term "flexible" means capable of bending about a core having a radius of curvature of up to 7.6 centimeters (cm) (3 inches), in some embodiments, up to 6.4 cm (2.5 inches), 5 cm (2 inches), 3.8 cm (1.5 inches), or 2.5 cm (1 inch). In some embodiments, the flexible component can be bent about a radius of curvature of at least 0.635 cm (1 / 4 inch), 1.3 cm (1 / 2 inch), or 1.9 cm (3 / 4 inch).

[0060] The term "about" or "approximately" with respect to a value or shape means + / - 5% of that value or property or characteristic, but expressly includes the exact value.

[0061] The term "substantially" with respect to a property or characteristic means that the property or characteristic is exhibited to a greater extent than the opposite side of the property or characteristic is exhibited. For example, a "substantially" transparent substrate is one that transmits more radiation (e.g., visible light) than it does not transmit (e.g., absorb and reflect). Thus, a substrate that transmits more than 50% of visible light incident on its surface is substantially transparent, but a substrate that transmits 50% or less of visible light incident on its surface is not substantially transparent.

[0062] As used in this specification and the accompanying embodiments, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a fine fiber comprising "a compound" includes a mixture of two or more compounds. As used in this specification and the accompanying embodiments, the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0063] Unless otherwise indicated, all numerals of the expression amount or composition, characteristic measurement etc. used in this specification and embodiment should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters shown in the above description and the attached embodiment list can vary according to the desired characteristics sought to be obtained by those skilled in the art using the teachings of the present disclosure. At the very least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claimed embodiments, each numerical parameter should at least be interpreted according to the reported significant digits and by applying conventional rounding methods.

[0064] By definition, the total weight percentages of all ingredients in a composition equal 100 weight percent.

[0065] Various exemplary embodiments of the present disclosure will now be described. Various modifications and changes may be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, it should be understood that the embodiments of the present disclosure are not limited to the exemplary embodiments described below, but should be subject to the limiting factors shown in the claims and any equivalents thereof.

[0066] refer to Figure 1A By superimposing a Cartesian coordinate system on its structure, the microstructured surface can be characterized in three dimensions. A first reference plane 124 is centered between major surfaces 112 and 114. First reference plane 124, referred to as the yz plane, has the x-axis as its normal vector. A second reference plane 126, referred to as the xy plane, extends substantially coplanar with surface 116 and has the z-axis as its normal vector. A third reference plane 128, referred to as the xz plane, is centered between first end surface 120 and second end surface 122 and has the y-axis as its normal vector.

[0067] In some embodiments, these microstructured surfaces are three-dimensional on a macroscopic scale. However, on a microscopic scale (e.g., a surface area comprising at least two adjacent microstructures with valleys or channels disposed between the microstructures), the base layer / base member can be considered planar relative to the microstructures. The width and length of the microstructures are in the xy plane, and the height of the microstructures is in the z direction. Furthermore, the base layer is parallel to the xy plane and orthogonal to the z plane.

[0068] Transfer products

[0069] In a first aspect, a transfer article is provided. The transfer article comprises:

[0070] a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure;

[0071] a peeling layer, the peeling layer being disposed on the plurality of microstructures, wherein the peeling layer comprises a metal layer or a doped semiconductor layer;

[0072] a (co)polymer layer disposed on a major surface of the release layer opposite the microstructured film; and

[0073] A multilayer optical film is disposed on a major surface of the (co)polymer layer relative to the release layer, wherein the multilayer optical film includes one or more alternating first and second inorganic optical layers, and the one or more alternating first and second inorganic optical layers jointly reflect and absorb light normally incident on the first major surface of the microstructured film, and on average reflect and absorb at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0074] In a second aspect, another transfer article is provided. The transfer article comprises:

[0075] a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure;

[0076] a lift-off layer disposed on the plurality of microstructures, wherein the lift-off layer comprises a metal layer or a doped semiconductor layer; and

[0077] A (co)polymer layer is disposed on a major surface of the release layer opposite the microstructured film, wherein the (co)polymer layer further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

[0078] The following disclosure relates to both the first aspect and the second aspect.

[0079] Reference again Figure 1A , “light normally incident on the first major surface of the microstructured film” refers to light that strikes the first major surface 116 of the microstructured film normal to the reference plane 126 (and parallel to the reference plane 124 ).

[0080] Now refer to Figure 1B, provides a schematic cross-sectional view of a microstructured film 100 that includes a plurality of microstructures 140 suitable for exemplary transfer articles and articles of the present disclosure. "A microstructure having a surface having a slope such that light normally incident on a first major surface of the microstructured film intersects the surface of the first major surface or at least one other microstructure after reflection" refers to incident light ("I") that strikes the surface of a microstructure 140a orthogonally to the first major surface 130 of the microstructured film 100, and the microstructure 140a has a slope 142 such that reflected light ("R") intersects the surface of the first major surface or another microstructure 140b of the microstructured film (not shown). In this case, if the reflected light does not intersect the surface of the microstructure 140b, the valley (e.g., bottom) 147 between two adjacent microstructures 140a and 140b can be the portion of the first major surface that intersects the reflected light. According to the above description with respect to Figure 1A For purposes of this discussion, the first major surface 130 of the microstructured film 100 is considered to be parallel to the second major surface 110 of the microstructured film 100. The slope 142 of a microstructure 140a (e.g., a sloped surface) is the height 141 of the microstructure 140a divided by the width 143 between the peak (e.g., the high end of the sloped surface) 145 and the bottom (e.g., the low end of the sloped surface) 147 of the microstructure 140a. Another way to determine the slope is to use the following formula:

[0081]

[0082] Where m is the slope, Δy is the height of the microstructure, Δx is the width between the peak and the bottom of the microstructure, and angle β is the tilt angle between the sloped surface of the microstructure and the bottom of the microstructure (e.g., Figure 1B For microstructures with rounded peaks, using the tangent of the tilt angle β may be a preferred way to determine the slope. An angle alpha (α) can be drawn between the slope 142 and the height 141 of the peak 145. In some cases, the angle α is 45 degrees or less, 40 degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, or 10 degrees or less.

[0083] Figure 1Cis a schematic cross-sectional view of a portion of an exemplary transfer article 10 according to at least some exemplary embodiments disclosed herein. Structured transfer article 10 includes a microstructured film 18 having a first major surface 21 and an opposing second major surface 23. First major surface 21 includes a plurality of microstructures 45 protruding therefrom. Transfer article 10 includes a release layer 16 positioned on the plurality of microstructures 45. Release layer 16 will be described in more detail below. Transfer article 10 also includes a (co)polymer layer 15 disposed on a major surface of release layer 16 opposite microstructured film 18, and a multilayer optical film 5 disposed on a major surface of (co)polymer layer 15 opposite release layer 16. Multilayer optical film 5 includes alternating first inorganic optical layers 12 and second inorganic optical layers 13.

[0084] Now see Figure 2 , the present disclosure describes structured transfer articles 10 and 20. Both transfer articles 10 and 20 include: a microstructured film 18 having a first major surface 21 and a second major surface 23; a release layer 16 positioned on the first major surface 21 (e.g., positioned on the plurality of microstructures of the microstructured film); and a (co)polymer layer 15 positioned on a major surface 27 of the release layer 16 opposite the microstructured film 18. Note that in this figure, for simplicity, the schematic depictions of various features do not show any microstructures. Optionally, the (co)polymer layer 15 is a first (co)polymer layer, and the transfer article (10 or 20) further includes a second (co)polymer layer 17 positioned between the microstructured film 18 and the release layer 16.

[0085] The transfer article 10 also includes a multilayer optical film 5 positioned on a major surface 29 of the (eg, first) (co)polymer layer 15 .

[0086] The multilayer optical film 20 includes one or more alternating first inorganic optical layers 12 (AN) and second inorganic optical layers 13 (AN).

[0087] Microstructured films

[0088] As mentioned above, a microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects the surface of the first major surface or at least one other microstructure after reflection. Thus, microstructures of various shapes are suitable. For example, in some cases, the microstructures have the shape of prisms, pyramids, inverted pyramids, diffraction gratings, inverted cones, or cones. Such shapes are described in further detail below. Additionally, the inverse of any of these shapes is also suitable. Any number of faces of a three-dimensional shape may be present (e.g., any of a 4-sided pyramid, a 5-sided pyramid, a 6-sided pyramid, etc. would be suitable).

[0089] In selected embodiments, each of the microstructures has the same size and shape, which often helps achieve consistent optical performance across the surface of the structured article for the multilayer optical film deposited on the microstructures. In selected embodiments, each surface has the same slope, where the slope of the surface is such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure. In this case, the microstructures do not necessarily have to have the same size or shape, only the same slope.

[0090] Optionally, at least some of the microstructures have a shape with a triangular cross-section, such as Figure 1B and Figure 1C 1 and 40. Although not required, in some cases, at least some of microstructures 140 include at least one angled sidewall (e.g., 142) having a peak 145. Advantageously, it has been discovered that multilayer optical films can be formed on microstructures having peaks (e.g., not rounded at the peaks) without having "pinholes" due to inadequate deposition of the multilayer optical film on the peaks.

[0091] In some cases, such as Figure 1B As depicted, at least some of the microstructures 140 include at least one angled sidewall (e.g., 142) having a peak angle (e.g., apex angle) theta (θ) of 90 degrees or less, 85 degrees, 80 degrees, 75 degrees, 70 degrees, 65 degrees, 60 degrees, 55 degrees, 50 degrees, or 45 degrees or less; and 5 degrees or greater, 7 degrees, 10 degrees, 12 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, or 50 degrees or greater. As used herein, "peak angle" refers to the angle between opposing sides of a microstructure at its apex.

[0092] Optionally, the plurality of microstructures 140 may have an aspect ratio of height H to (total) width W (ie, H:W) of no more than 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or no more than 1:1; and at least 1:2.

[0093] Typically, the microstructures each have a height of 0.5 micrometers or greater, 1 micrometer, 2 micrometers, 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 12 micrometers, 15 micrometers, 17 micrometers, 20 micrometers, 25 micrometers, 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 110 micrometers, 120 micrometers, 150 micrometers, 160 micrometers, 175 micrometers, 180 micrometers, 190 micrometers, 200 micrometers, 250 micrometers, 300 micrometers, 350 micrometers, 400 micrometers, 450 micrometers, 500 micrometers, 600 micrometers, 700 micrometers, 800 micrometers, 900 micrometers, 1000 micrometers, 1100 micrometers, 1200 micrometers, 1500 micrometers, 1800 micrometers, 1800 micrometers, 1800 micrometers, 1800 micrometers, 0 microns, 175 microns, 200 microns, 225 microns, or 250 microns or greater; and 500 microns or less, 475 microns, 450 microns, 425 microns, 400 microns, 375 microns, 350 microns, 325 microns, 300 microns, 275 microns, 250 microns, 225 microns, 200 microns, 175 microns, 150 microns, 125 microns, 100 microns, 75 microns, 50 microns, or 25 microns or less.

[0094] refer to Figure 3 In one embodiment, the first major surface 300 of the microstructured film 100 comprises a linear array of right rectangular prisms 320. Each prism has a first face (e.g., an inclined surface) 321 and a second face 322. The prisms are illustrated as being formed on a base member 310 having a first planar surface 331 (parallel to reference plane 126) on which the prisms are formed and a second surface 332 that is substantially flat or planar and opposite the first surface. It is contemplated that the second surface 332 may also be structured. Right-angled prisms mean that their peak angle θ 340 is typically about 90 degrees. However, this angle can range as described above. The peaks can be sharp (as shown) or rounded. The spacing between the peaks (e.g., of the prisms) can be characterized as pitch ("P"). In this embodiment, the pitch is also equal to the maximum width of the valley. The pitch can be greater than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 microns, and can range up to 250 microns. The length ("L") of the (e.g., prism) microstructures is typically the largest dimension and can span the entire dimension of the microstructured surface. In selected cases, the linear prisms are oriented to extend across the width (e.g., cross-web direction) of the microstructured surface, rather than down the length (e.g., down-web direction) of the microstructured surface.

[0095] In another embodiment, the first major surface of the microstructured film can have the same surface shape as cube corner retroreflective sheeting. Figure 4A, cube corner retroreflective sheeting generally includes a thin transparent layer having a substantially planar surface and an opposing structured surface 410 that includes a plurality of cube corner elements 417 . Figure 4A The microstructured surface 410 can be characterized as an array of cube-corner elements 417 defined by three sets of parallel grooves (i.e., valleys) 411, 412, and 413; two sets of grooves (i.e., valleys) intersect each other at an angle greater than 60 degrees, and the third set of grooves (valleys) intersects each of the other two sets at an angle less than 60 degrees to form an array of matched pairs of inclined cube-corner elements (see U.S. Patent No. 4,588,258 (Hoopman)). The angles of the grooves are selected so that the dihedral angles formed at the linear intersections of the grooves (e.g., 414, 415, and 416 of representative cube-corner elements 417) are about 90 degrees. In some embodiments, the angle of the triangular base is at least 64, 65, 66, 67, 68, 69, or 70 degrees, and the other angles are 55, 56, 57, or 58 degrees.

[0096] In another embodiment, Figure 4B Depicted, Figure 4B The first major surface of the microstructured film 400 can be characterized as an array of pyramidal peak structures 420 defined by a first set of parallel grooves (i.e., valleys) in the y-direction and a second set of parallel grooves in the x-direction. The base of the pyramidal peak structures is polygonal, typically square or rectangular, depending on the spacing of the grooves. The peak angle θ 440 is typically about 90 degrees. However, this angle can range as described above.

[0097] In some cases, the microstructures can have a conical shape. Figure 5 , the microstructured surface 500 of the microstructured film comprises an array of cones 540. Each microstructure of the cone shape typically has only one angled sidewall 542. The peak 545 of each cone can be pointed or rounded.

[0098] Figure 6 A schematic diagram of a first major surface 600 of a microstructured film comprising a diffraction grating having an offset angle is depicted. The second major surface 610 of the microstructured film defines a longitudinal axis ("LA") along its length, and a plurality of microstructures 640 extend across the first major surface 600 to define a major axis ("A"). The major axis A and the longitudinal axis LA define an offset angle ("B") therebetween. In some embodiments, the offset angle B is within a range between about 0 degrees and about 90 degrees, such as between about 20 degrees and about 70 degrees.

[0099] In another embodiment, Figure 7As depicted, the first major surface 710 of the microstructured film 700 can be characterized as an array of inverted pyramidal structures 720. The structures 720 include faces 722 that meet in valleys (e.g., inverted peaks) 721, and the opposing edges 724 of each face together form the base of the pyramidal structure 720 (i.e., at the outermost surface of the microstructured film 700). The base of the pyramid is a polygon, such as a square or rectangle. In this particular embodiment, adjacent rows of structures (e.g., end row 762 is adjacent to row 764) are offset from each other so that the bottoms of the valleys of adjacent structures (e.g., 723 in row 762 and adjacent structures 725 in row 764) have different locations along the length of the row (e.g., on the y-axis). It is expressly contemplated that such an offset configuration can be employed with any of the microstructures disclosed herein.

[0100] In another embodiment, Figure 8 As depicted, the first major surface 810 of the microstructured film 800 can be characterized as an array of inverted cones 820. The cone structures 820 include curved walls 822 that terminate in valleys (e.g., inverted peaks) 821, and edges 824 of the walls 822 opposite the valleys 821 together form the bases of the cone structures 820 (i.e., at the outermost surface of the microstructured film 800). The bases of the cones can be polygonal (such as a hexagon, pentagon, square, rectangle, or triangle) or circular or elliptical.

[0101] In some cases, the microstructured film is flexible (as defined in the glossary). An advantage of using a flexible microstructured film is that it avoids the high cost of using rigid glass, especially small glass pieces, which may break during processing and the labor-intensive process of applying many small glass pieces. Additionally, in some embodiments according to the present disclosure, the flexible microstructured film is used in a roll-to-roll process for making structured articles and transfer articles. An advantage of roll-to-roll manufacturing is that structured articles and transfer articles can be made in large area form factors. In some cases, the microstructured film (or article / transfer article) has an area of at least 50 square centimeters (such as at least 60 square centimeters, 70 square centimeters, 80 square centimeters, 90 square centimeters, 100 square centimeters, 1,000 square centimeters, or at least 10,000 square centimeters).

[0102] In any of the foregoing embodiments, the microstructured film may be composed of or comprised of a polymeric material such as a (co)polymer. In some exemplary embodiments, the microstructured film comprises polyethylene terephthalate (PET), cured polysiloxanes, silicone thermoplastic polymers, cured polyurethanes, thermoplastic polyurethanes, cured (meth)acrylates, cured epoxies, cured vinyl ethers, cured oxetanes, cured thiol acrylates, cured thiol ene, polypropylene, polyethylene, polymethyl methacrylate (PMMA), coPMMA, polyimides, cyclic olefin copolymers, cyclic olefin polymers, polycarbonates, polyethylene naphthalate (PEN), or fluoropolymer (co)polymers comprising polymerized units derived from one or more monomers selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, perfluoroalkoxyalkylene, or vinyl fluoride, or combinations thereof. Optionally, any of the above-mentioned cured polymeric materials is cross-linked.

[0103] Suitable polyimides are available from EI DuPont de Nemours, Wilmington, DE, under the trade designation "KAPTON," with "KAPTON CS100" being presently preferred. Suitable PMMA polymers include those available from Ineos Acrylics, Inc., Wilmington, DE, as CP71 and CP80. A suitable cross-linkable silicone is available from Dow Corning Corporation, Midland, MI, under the trade designation "DOW CORNING 93-500 Aerospace Grade Encapsulation Material Kit." A suitable polycarbonate is available from Bayer AG, Darmstadt, Germany, under the trade designation "Makrofol." Suitable methyl methacrylate copolymers (CoPMMA) include, for example, CoPMMA made from 75% by weight methyl methacrylate (MMA) monomers and 25% by weight ethyl acrylate (EA) monomers (e.g., available under the trade designation "PERSPEX CP63" from Acrylics, Inc., London, England, or "ATOGLAS 510" from Arkema Corp., Philadelphia, PA); CoPMMA formed from MMA comonomer units and n-butyl methacrylate (nBMA) comonomer units; or a blend of PMMA and poly(vinylidene fluoride) (PVDF). Suitable polyethylene naphthalate (PEN) polymers are available under the trade designation "Teonex Q51" from DuPont Teijin, Chester, VA.

[0104] In certain exemplary embodiments, the fluorine-containing (co)polymer preferably comprises tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, perfluoroalkoxyalkanes, or combinations thereof. Suitable fluorine-containing polymers are available from E.I. DuPont de Nemours, Wilmington, Delaware under the trade name "TEFLON FEP100," with "TEFLON FEP100500A" being currently preferred. Suitable exemplary fluoropolymers also include copolymers of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride (THV) available from Dyneon LLC, Oakdale, MN, under the trade designations “DYNEON THV 220,” “DYNEON THV 221,” “DYNEON THV 230,” “DYNEON THV 2030,” “DYNEON THV 415,” “DYNEON THV 500,” “DYNEON THV 610,” and “DYNEON THV 815.”

[0105] In some applications, for example, when the article will be subjected to large ambient temperature changes, it may be useful to employ a film having a low coefficient of thermal expansion (CTE). Some exemplary low CTE polymers include, for example, but are not limited to, polyimides, thermally stable PEN, and PET. Preferably, the low CTE material has a CTE of 80 parts per million per Kelvin (ppm / K) or less, 70 ppm / K, 60 ppm / K, 50 ppm / K, 40 ppm / K, 30 ppm / K, or even 25 ppm / K or less. The coefficient of thermal expansion has the general meaning employed in the art, i.e., is determined using ASTM E831.

[0106] The smoothness and adhesion of the layers to the microstructured film can be enhanced by subjecting the microstructured film to an appropriate optional pretreatment or optionally applied primer. Methods of surface modification are known in the art. In one embodiment, the pretreatment regimen includes discharge pretreatment (e.g., plasma, glow discharge, corona discharge, dielectric barrier discharge, or atmospheric pressure discharge), chemical pretreatment, or flame pretreatment of the substrate in the presence of a reactive or non-reactive atmosphere. These pretreatments can help ensure that the surface of the microstructured film will be receptive to the subsequently applied layers. In one embodiment, the method can include a plasma pretreatment. For organic surfaces, the plasma pretreatment can include nitrogen or water vapor. Another pretreatment regimen includes coating the microstructured film with an inorganic or organic primer, optionally followed by further pretreatment using plasma or one of the other pretreatments described above.

[0107] Preferably, the microstructured film itself transmits, on average, at least 70%, 80%, 90%, or 95% of incident visible light within the wavelength range of greater than 400 nm to 700 nm.

[0108] peeling layer

[0109] The exfoliation layer may include a metal layer. The metal layer may include at least one selected from the group consisting of a single metal, two or more metals as a mixture, an intermetallic compound or alloy, a semimetal or metalloid, a metal oxide, a metal and mixed metal oxide, a metal and mixed metal fluoride, a metal and mixed metal nitride, a metal and mixed metal carbide, a metal and mixed metal carbonitride, a metal and mixed metal oxynitride, a metal and mixed metal boride, a metal and mixed metal boron oxide, a metal and mixed metal silicide, diamond-like carbon, diamond-like glass, graphene, and combinations thereof. In some embodiments, the metal layer may be conveniently formed of Al, Zr, Cu, NiCr, Ti, or Nb. In selected embodiments, the exfoliation layer comprises copper oxide. In selected embodiments, the exfoliation layer comprises silicon aluminum oxide. Suitable thicknesses of the exfoliation layer range from 1 nm to 3000 nm.

[0110] Alternatively, the stripping layer may include a doped semiconductor layer. In some embodiments, the doped semiconductor layer can be conveniently formed by Si, B-doped Si, Al-doped Si, or P-doped Si having a thickness between 1 nm and 3000 nm. A particularly suitable doped semiconductor layer is Al-doped Si, wherein the Al component percentage is 10%. The stripping layer can typically be prepared by evaporation, reactive evaporation, sputtering, reactive sputtering, chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition. Preferred methods include vacuum preparation, such as sputtering and evaporation. In at least some embodiments according to the present disclosure, the transfer article exhibits a stripping value of 2 grams per inch (g / in) to 50 grams per inch between the stripping layer and the (e.g., first) (co)polymer layer. When it is necessary to transfer the article to another substrate, such a stripping value enables the stripping layer to be easily removed.

[0111] (Co)polymer layer

[0112] Exemplary transfer articles include at least one (co)polymer layer. Figure 2 , (co)polymer layer 15 covers first major surface 27 of release layer 16. Optionally, (co)polymer layer 15 is a first (co)polymer layer, and the transfer article (10 or 20) further comprises a second (co)polymer layer 17 covering first major surface 21 of microstructured film 18. In selected embodiments, the (co)polymer layer is substantially transparent.

[0113] Each (co)polymer layer comprises a (co)polymer independently selected from olefin (co)polymers, (meth)acrylate (co)polymers, polyurethane (co)polymers, fluoropolymers, silicone (co)polymers, or combinations thereof.

[0114] (Being total to) polymer layer can use multiple technology to be formed by multiple organic materials or compound.After applying, (being total to) polymer layer can in situ crosslinking.In one embodiment, can be by using the flash distillation, vapor deposition and (being total to) polymerization formation (being total to) polymer layer of monomer such as heating, plasma, UV radiation or electron beam.

[0115] Exemplary monomers used in this method include volatile (meth)acrylate monomers. In a specific embodiment, a volatile acrylate monomer is used. Suitable (meth)acrylates will have a molecular weight low enough to allow flash evaporation and high enough to allow condensation on the substrate. The organic material or compound can also be evaporated using any method, such as the method described in PCT Publication No. WO 2022 / 243756 (Sweetnam et al.), such as the method described with respect to evaporating metal alkoxides.

[0116] If desired, the (co)polymer layer may 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 layer will depend in part on the nature and desired use of the article. Coating efficiency can be improved by cooling the article.

[0117] Exemplary organic compounds include esters, vinyl compounds, alcohols, carboxylic acids, 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 monoacrylate, isobornyl acrylate, octadecyl acrylate, isodecyl acrylate, lauryl acrylate, β-carboxyethyl acrylate, tetrahydrofurfuryl acrylate, dinitrile acrylate, pentafluorophenyl acrylate, nitrophenyl acrylate, 2-phenoxyethyl acrylate, 2,2,2-trifluoromethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, tetraethylene glycol diacrylate, Examples of the present invention include acrylates such as propylene glycol, propylene glycol, propylene glycol, propylene glycol acrylate ... Exemplary carboxylic acids include phthalic acid, terephthalic acid, and (meth)acrylic acid. Exemplary anhydrides include phthalic anhydride and glutaric anhydride. Exemplary acyl halides include adipic acid dichloride and succinyl chloride. Exemplary thiols include ethylene glycol dimercaptoacetate and phenylthioethanol acrylate. Exemplary amines include ethylenediamine and hexane 1,6-diamine.

[0118] Optionally, at least one (co)polymer layer further comprises an additive, which is an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof. Specifically, in the transfer article of the selected embodiment of the present disclosure, the (co)polymer layer and / or the microstructured film further comprises an additive, which is an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof. UV absorbers (UVA), hindered amine light stabilizers (HALs) and antioxidants can help prevent photooxidative degradation of the (co)polymer layer. Suitable compounds include benzophenones, benzotriazoles and triazines (e.g., benzotriazine). Exemplary UVAs for incorporation into the (co)polymer layer include those available from BASF Corporation, Florham Park, NJ, under the trade names "TINUVIN 1577" and "TINUVIN 1600." U.S. Patent No. 9,670,300 (Olson et al.) and U.S. Patent Application Publication No. 2017 / 0198129 (Olson et al.) describe exemplary UVA oligomers compatible with PVDF fluoropolymers. Exemplary HALs for incorporation include those available from BASF Corporation under the trade names "CHIMMASORB 944" and "TINUVIN 123." Typically, the UVA, HAL, and / or antioxidant are incorporated into the (co)polymer layer at a concentration of 1% to 10% by weight.

[0119] In certain embodiments, the (co)polymer layer is preferably cross-linked.

[0120] In some exemplary embodiments, the outer (co)polymer layer comprises an olefin (co)polymer selected from the group consisting of low density polyethylene, linear low density polyethylene, ethylene vinyl acetate, polyethylene methyl acrylate, polyethylene octene, polyethylene propylene, polyethylene butylene, polyethylene maleic anhydride, polymethylpentene, polyisobutylene, polyisobutylene, polyethylene propylene diene, cyclic olefin (co)polymers, and blends thereof.

[0121] In certain exemplary embodiments, the (co)polymer further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

[0122] The ultraviolet radiation absorber is preferably selected from benzotriazole compounds, benzophenone compounds, triazine compounds, or combinations thereof. Currently preferred hindered amine light stabilizers are commercially available from BASF USA, Florham Park, NJ, under the trade designation "TINUVIN". Preferably, the hindered amine light stabilizer is selected from TINUVIN 123, TINUVIN 144, TINUVIN 292, or combinations thereof. Currently preferred antioxidants are commercially available from BASF under the trade designations "IRGANOX" and "IRGAFOS". Preferably, suitable antioxidants for polyolefins are selected from IRGANOX 1010, IRGANOX 1076, IRGAFOS 168, or combinations thereof.

[0123] Multilayer optical films

[0124] Reference again Figure 2 , the transfer article 10 includes a multilayer optical film 5, which includes one or more alternating first inorganic optical layers 12 (AN) and second inorganic optical layers 13 (AN), and the one or more alternating first inorganic optical layers and second inorganic optical layers are positioned on the first major surface 29 of the (co)polymer layer 15, as further described below.

[0125] Typically, the multilayer optical film has a thickness of 200 nm or greater, 250 nm, 300 nm, 350 nm, 400 nm, 500 nm, or 550 nm or greater; and 1500 nm or less, 1400 nm, 1300 nm, 1200 nm, 1100 nm, 1000 nm, 900 nm, 850 nm, 800 nm, 750 nm, 700 nm, 650 nm, or 600 nm or less, such as 200 nm to 1500 nm.

[0126] Inorganic layer

[0127] In some cases, the first optical layer comprises at least one of niobium oxide, titanium oxide, silicon oxynitride, molybdenum oxide, tungsten oxide, silicon nitride, indium tin oxide, hafnium oxide, tantalum oxide, zirconium oxynitride, zirconium oxide, zinc aluminum oxide, or zinc oxide. As known to those skilled in the art, alloys of oxides may be suitable. In some cases, the second optical layer comprises at least one of silicon oxide, silicon aluminum oxide, N-type or P-type doped silicon oxide, aluminum oxide, aluminum fluoride, magnesium fluoride, calcium fluoride, indium tin oxide, or zinc oxide. In selected embodiments, the first optical layer comprises at least one of niobium oxide or titanium oxide, and the second optical layer comprises silicon aluminum oxide. When a photoactive inorganic material (such as titanium oxide) is employed, a non-photoactive material (e.g., silicon oxide, aluminum oxide, etc.) may typically be provided between the photoactive inorganic material and any organic layer to minimize degradation of the organic layer. For example, again referring to Figure 2 , the non-photoactive material layer can be an intermediate layer 19 located between the first optical layer 12A and the second microstructured film 11 .

[0128] It has been unexpectedly discovered that using only the combined reflectivity and absorptivity of a plurality of alternating first and second inorganic optical layers, wavelengths of light in each of the UVA, UVB, and UVC regions can be shielded from the microstructured film while generally still maintaining an acceptable amount of visible light transmission (e.g., at least 50% of incident visible light).

[0129] Optical thin film stack designs, consisting of alternating thin layers of inorganic dielectric materials with contrasting refractive indices, are particularly well-suited for multilayer optical films. These designs have been used for applications in the UV, visible, NIR, and IR spectral regions for decades. Depending on the spectral region of interest, specific materials exist for that region. Furthermore, for coating these materials, one of two forms of physical vapor deposition (PVD) is used: evaporation or sputtering. Evaporative coatings rely on heating the coating material (evaporant) to a temperature at which it evaporates. This is followed by condensation of the vapor on the substrate. For evaporated dielectric mirror coatings, the electron beam deposition process is most commonly used. Sputtering coatings use high-energy gas ions to bombard the surface of a material (the "target"), ejecting atoms that subsequently condense on a nearby substrate. Depending on the coating method used and the setup used for that method, the film coating rate and structure-property relationships are strongly influenced. Ideally, the coating rate should be high enough to allow acceptable process throughput and film performance, characterized by a dense, low-stress, void-free, non-optically absorbing coating.

[0130] For reasons of film thickness, flexibility, and economy, the number of optical layers is selected to achieve the desired optical properties using the minimum number of layers. Those skilled in the art can extend such deposition techniques to include CVD, ALD, and other vapor deposition techniques. Generally, it is preferred that the total number of layers be 21 or fewer, 19, 17, 15, or 13 or fewer optical layers; and 3 or more optical layers, 5, 7, 9, or 11 or more optical layers may be desired. In selected embodiments, the multilayer optical film is formed from at least one first optical layer and two second optical layers.

[0131] The thickness of each of the first and second optical layers can vary significantly. For example, in some cases, each of the first and second optical layers independently has a thickness of 5 nm or more, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, or 70 nm or more; and 2000 nm or less, 500 nm, 145 nm, 140 nm, 135 nm, 130 nm, 125 nm, 120 nm, 115 nm, 110 nm, 105 nm, 100 nm, 95 nm, 90 nm, 85 nm, 80 nm, or 75 nm or less. In selected embodiments, each of the first and second optical layers independently has a thickness of 20 nm to 400 nm.

[0132] The multilayer optical films described herein can be made using common processing techniques, such as those described in US Pat. No. 6,783,349 (Neavin et al.), the entire disclosure of which is incorporated herein by reference.

[0133] For the manufacture of inorganic coatings, electron beam processes are most suitable for coating discrete components. Optionally, products or transfer products can be prepared in a continuous roll-to-roll (R2R) manner for larger products. Although some chambers have shown R2R film coating, a layer-by-layer coating sequence is still necessary. For R2R sputtering of the inorganic layer of a product or transfer product, it is advantageous to use a sputtering system with multiple sources located around one or possibly two coating drums. Here, for an optical stack design of thirteen layers, a dual or even single machine with alternating high refractive index layers and low refractive index layers will be feasible. How many machines will be needed will depend on the practicality of the machine design, cost, thirteen continuous sources, etc. In addition, the coating rate will need to match the single film line speed.

[0134] The film roll transport initially starts at a predetermined speed, and the sputtering source power is ramped up to full operating power, then the reactive gas is introduced and steady-state conditions are achieved. Depending on the length of the film to be coated, the process continues until the total footprint is achieved. Here, since the sputtering sources are orthogonal to and wider than the film being coated, the uniformity of the coating thickness is quite high. When the desired length of the coated film is reached, the reactive gas is set to zero and the target is sputtered to a pure metal surface state. Next, the film direction is reversed, and the rotating pair of sputtering targets has AC frequency (40kHz) power applied in an argon sputtering atmosphere. When steady-state is reached, oxygen reactive gas is introduced to provide transparency and low refractive index. Under predetermined process settings and line speeds, the second layer is coated on the length coated for layer one. Similarly, since these sputtering sources are also orthogonal to and wider than the film being coated, the uniformity of the coating thickness is quite high. After the desired length of the coated film is reached, the reactive oxygen is removed and the target is sputtered to a pure metal surface state in argon. Depending on the phototarget, three to five layers (or seven or nine, eleven or thirteen, etc.) are applied in this order. After completion, the film roll is removed for post-processing.

[0135] The transferred article may be subjected to various post-treatments, such as heat treatment, UV or vacuum UV (VUV) treatment, electron beam treatment, or plasma treatment. Heat treatment may be performed by passing the article through an oven or directly heating the article in a coating apparatus (e.g., using an infrared heater or heating directly on a drum). For example, heat treatment may be performed at a temperature of about 30°C to about 200°C, about 35°C to about 150°C, or about 40°C to about 70°C.

[0136] Products

[0137] In a third aspect, a product is provided. The product comprises:

[0138] a first microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the first microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure;

[0139] a peeling layer, the peeling layer being disposed on the plurality of microstructures, wherein the peeling layer comprises a metal layer or a doped semiconductor layer;

[0140] a (co)polymer layer disposed on a major surface of the release layer opposite the first microstructured film;

[0141] a multilayer optical film disposed on a major surface of the (co)polymer layer opposite the release layer; and

[0142] a second microstructured film adjacent a major surface of the multilayer optical film opposite the (co)polymer layer, wherein the second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure;

[0143] The multilayer optical film comprises one or more alternating first and second inorganic optical layers, which together reflect and absorb light normally incident upon the first major surface of the second microstructured film, and reflect and absorb, on average, at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0144] In a fourth aspect, another article is provided. The article comprises:

[0145] a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure;

[0146] A multilayer optical film disposed on the plurality of microstructures, wherein the multilayer optical film comprises one or more alternating first and second inorganic optical layers that collectively reflect and absorb light normally incident upon the first major surface of the microstructured film, reflecting and absorbing, on average, at least 50%, 60%, 70%, 80%, 90%, or 95% of incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm; and a (co)polymer layer disposed on a major surface of the multilayer optical film relative to the microstructured film.

[0147] The following disclosure relates to both the third aspect and the fourth aspect.

[0148] Reference again Figure 2, article 30 includes a first microstructured film 18 including a first major surface 21 and an opposing second major surface 23, and a release layer 16 disposed on the first major surface 21 of the first microstructured film 18. Article 30 also includes a (co)polymer layer 15 disposed on a major surface 27 of the release layer 16 opposite the first microstructured film 18, and a multilayer optical film 5 disposed on a major surface 29 of the (co)polymer layer 15 opposite the release layer 16. Additionally, article 30 includes a second microstructured film 11 adjacent to a major surface 7 of the multilayer optical film 5 opposite the (co)polymer layer 15. Optionally, the (co)polymer layer 15 is a first (co)polymer layer, and article 30 further includes a second (co)polymer layer 17 disposed between the first microstructured film 18 and the release layer 16.

[0149] Now refer to Figure 1D , article 30 includes a first microstructured film 18 and a release layer 16, the first microstructured film including a first major surface 21 including a plurality of microstructures 45 protruding therefrom, the release layer being disposed on the microstructures 45. Article 30 also includes a (co)polymer layer 15 disposed on the release layer 16 opposite the first microstructured film 18, and a multilayer optical film 5 disposed on a major surface 29 of the (co)polymer layer 15 opposite the release layer 16. Additionally, article 30 includes a second microstructured film 11 adjacent to a major surface 8 of the multilayer optical film 5 opposite the (co)polymer layer 15. The second microstructured film 11 includes a first major surface 7 and an opposing second major surface 9, wherein the first major surface 7 includes a plurality of microstructures 47 protruding therefrom, wherein at least some of the plurality of microstructures 47 each have a surface having a slope such that light normally incident on the first major surface 7 of the second microstructured film 11 intersects the first major surface 7 or a surface of at least one other microstructure after reflection. In some cases, second microstructured film 11 is directly adjacent to multilayer optical film 5, while in other cases, an intervening layer (not shown) may be present between the two.

[0150] As in Figure 1D As can be seen in the figure, the microstructures 47 of the second microstructured film 11 have an inverted shape relative to the microstructures 45 of the first microstructured film 18. In the final application use, the article will include the second microstructured film 11, so the shape of the microstructures 45 of the first microstructured film 18 should be selected to be the inverse of the desired shape of the microstructures 47 of the second microstructured film 11.

[0151] In use, the product will Figure 1Doriented opposite to the orientation depicted in , so that incident light will reach the microstructures 47 of the first major surface 7 of the second microstructured film 11 before reaching the opposing second major surface 9 of the second microstructured film 11. According to at least certain embodiments disclosed herein, the article of the fourth aspect (i.e., an article having only one microstructured film) transmits light normally incident on the first major surface of the second microstructured film by an average of at least 50%, 60%, 70%, 80%, 90%, or 95% of the normally incident visible light over the wavelength range of greater than 400 nm to 700 nm. Upon exposure to 425 megajoules per square meter (MJ / m 2 ), the articles according to certain preferred embodiments of the present disclosure exhibit an average transmittance reduction of less than 20%, less than 10%, less than 5%, or less than 1% at wavelengths between 400 nm and 700 nm through the article.

[0152] In selected embodiments, in use, the outermost inorganic layer is the second inorganic optical layer (e.g., Figure 2 The invention also provides a method for preparing a thin film of the invention comprising: preparing a thin film of the invention comprising: a first film of the invention comprising: a first film of the invention comprising: a second ...

[0153] In selected embodiments, in use, the first optical layer closest to the article (e.g., Figure 2 12N in) on the outside or closest to the microstructured film (e.g., Figure 2 In one embodiment, the thickness of at least one first optical layer in the first optical layer 12A) is at most 95%, 90%, 85%, or at most 80% of the thickness of the other first optical layers. This has the effect of reducing the amount of light reflected from the outer surface of the article between 400 nm and 700 nm, which is particularly useful when the article is used in solar energy applications to allow visible light to reach the solar cells.

[0154] The alternating first inorganic optical layers and the second inorganic optical layers collectively reflect and absorb light normally incident on the first major surface of the microstructured film 11, and on average reflect and absorb at least 50%, 60%, 70%, 80%, 90% or 95% (preferably at least 80%, 90% or 95%) of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0155] In some cases, the alternating first and second inorganic optical layers collectively reflect and absorb light normally incident on the first major surface of the microstructured film 11, and on average reflect and absorb at least 60%, 70%, 80%, 90%, or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nm to 240 nm, 240 nm to 300 nm, 300 nm to 350 nm, 350 nm to 400 nm, or any combination thereof.

[0156] Optionally, the alternating first inorganic optical layers and second inorganic optical layers collectively reflect and absorb light normally incident on the first major surface of the microstructured film 11, and on average reflect and absorb at least 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a wavelength reflection bandwidth greater than at least 30 nanometers (e.g., at least 50 nanometers, 75 nanometers, 100 nanometers, 125 nanometers, 150 nanometers or 175 nanometers) in the wavelength range of 190 nm to 400 nm.

[0157] When the alternating first and second inorganic optical layers jointly reflect and absorb, some portion of the incident ultraviolet light can be absorbed and some portion reflected. In some cases, the alternating first and second inorganic optical layers jointly absorb light normally incident on the first major surface of the microstructured film 11, absorbing an average of at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% of the incident light within a wavelength bandwidth of at least 30 nanometers within a wavelength range of 190 nm to less than 350 nm. In some cases, the alternating first and second inorganic optical layers collectively reflect light normally incident on the first major surface of the microstructured film 11, and on average reflect at least 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% of the incident light within a wavelength bandwidth of at least 30 nanometers within a wavelength range of 190 nm to less than 400 nm, 190 nm to 240 nm, 240 nm to 300 nm, 300 nm to 350 nm, 350 nm to less than 400 nm, or any combination thereof.

[0158] In selected embodiments, the alternating first and second inorganic optical layers collectively transmit light normally incident upon the first major surface of the microstructured film 11, and transmit an average of at least 50%, 60%, 70%, 80%, 90%, or 95% of the incident visible light over a wavelength range from greater than 400 nm to 700 nm.

[0159] In some embodiments, the article of the fourth aspect (i.e., an article having only one microstructured film) transmits, on average, at least 50%, 60%, 70%, 80%, 90%, or 95% of normally incident visible light in the wavelength range of from greater than 400 nm to 700 nm (e.g., as a whole). Transmitting such amounts of incident visible light is particularly useful when the article is used in solar array applications to allow visible light to reach the solar cells in the array.

[0160] exist Figure 1D and Figure 2 In the embodiment of the present invention, the article 30 further comprises an optional additional layer 14, which is an adhesive layer, a substrate, or both. The additional layer 14 is disposed on the major surface 9 of the second microstructured film 11 opposite the multilayer optical film 5. Many different materials are suitable for such adhesive and / or substrate layers, and the additional layer 14 encompasses a carrier substrate (e.g., a self-supporting substrate), a single adhesive layer, an adhesive tape, a double-sided adhesive, a tape, a primer adhesive layer, a film, etc. Thus, the additional layer can be, for example, Figure 1D A single layer is depicted, or there may be multiple layers.

[0161] Reference again Figure 2 , article 40 includes a microstructured film 11 having a first major surface 7 and an opposing second major surface 9. The first major surface 7 has a plurality of microstructures (not shown) protruding therefrom. Article 40 also includes a multilayer optical film 5 disposed on the first major surface 7 of the microstructured film 11, and a (co)polymer layer 15 disposed on a major surface 22 of the multilayer optical film 5 opposite the microstructured film 11.

[0162] The (e.g., first) microstructured film 18, release layer 16, (co)polymer layer 15, multilayer optical film 5, and optional second (co)polymer layer 17 are each as described in detail above with respect to the transfer articles of the first and second aspects. Optionally, the article further comprises an additional layer 14, which is an adhesive layer, a substrate, or both, as described above with respect to the transfer articles of the first and second aspects. Figure 1D As stated.

[0163] In some embodiments, the (e.g., second) microstructured film 11 comprises a cured polysiloxane, a silicone thermoplastic polymer, PET, a cured polyurethane, a thermoplastic polyurethane, a cured (meth)acrylate, a cured epoxy resin, a cured vinyl ether, a cured oxetane, a cured thiol acrylate, a cured thiol ene, PMMA, coPMMA, a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, PEN, or a fluoropolymer (co)polymer comprising polymerized units derived from one or more monomers selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, a perfluoroalkoxyalkylene, or vinyl fluoride, or a combination thereof. Optionally, any of the cured polymer materials described above is cross-linked. In the articles of selected embodiments of the present disclosure, the (co)polymer layer and / or the microstructured film further comprises an additive that is a UV radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof, such as any of the additives described above.

[0164] In some cases, the second microstructured film comprises a cured polysiloxane, a silicone thermoplastic polymer, or a combination thereof. An advantage of preparing an article from a transfer article is that a soft material (such as a silicone-based polymer) can be used without having to support the deposition of the multilayer optical film on the microstructured film during formation of the article.

[0165] When polyimides or high temperature fluoropolymers are employed, it is possible to combine with another polymeric material (eg, a cured (meth)acrylate) that forms the microstructures of the microstructured film as a generally planar backing layer.

[0166] In selected embodiments, the second microstructured film comprises cured polyurethane, cured (meth)acrylate, coPMMA, PMMA, or a combination thereof, and the second microstructured film optionally further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof. The inclusion of such additives can help protect the microstructured film material from UV radiation.

[0167] The article may be subjected to various post-treatments, such as heat treatment, UV or vacuum UV (VUV) treatment, electron beam treatment, or plasma treatment. Heat treatment may be performed by passing the article through an oven or directly heating the article in a coating apparatus (e.g., using an infrared heater or heating directly on a drum). For example, heat treatment may be performed at a temperature of about 30° C. to about 200° C., about 35° C. to about 150° C., or about 40° C. to about 70° C.

[0168] Any first microstructured film, first (co)polymer layer, second (co)polymer layer, release layer, multilayer optical film present in the article according to the third aspect or the fourth aspect can be generally as described in detail above with respect to those films and / or layers used in the transfer article of the first aspect or the second aspect.

[0169] method

[0170] In a fifth aspect, a method of manufacturing an article is provided. The method comprises:

[0171] obtaining a transfer product according to the first aspect or the second aspect;

[0172] depositing a polymeric or cross-linkable material on an outer major surface of the transfer article opposite the first microstructured film;

[0173] curing the polymeric material or the cross-linkable material to form a second microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure, and wherein the first major surface of the second microstructured film is adjacent to the multilayer optical film; and

[0174] The release layer is removed from the transfer article.

[0175] In some cases, the transfer article is a transfer article according to the first aspect, and the outer major surface of the transfer article comprises the major surface of the multilayer optical film opposite the (first) (co)polymer layer. In other words, in some cases, the transfer article used in this method comprises the following layers, in order: a microstructured film, a release layer, a (co)polymer layer, and a multilayer optical film, and the multilayer optical film is the outer layer of the transfer article. The term "outer layer" means that the layer is the outermost layer of the transfer article.

[0176] In some cases, the transfer article is a transfer article according to the first aspect, and the method further comprises removing the (first) (co)polymer layer after removing the release layer. In other words, in some cases, the transfer article used in the method comprises the following layers in order: a microstructured film, a release layer, a (co)polymer layer, and a multilayer optical film, and after stripping the release layer, the (co)polymer layer adjacent to the multilayer optical film is removed. Etching is typically used to remove the (co)polymer layer.

[0177] Suitable etching processes are not particularly limited and may include reactive ion etching or etching using any type of plasma. In one embodiment, the (co)polymer layer is removed by reactive ion etching. Reactive ion etching (RIE) is a directional etching process that utilizes ion bombardment to remove material. RIE systems are used to remove organic or inorganic materials by etching surfaces orthogonal to the direction of ion bombardment. The most significant difference between reactive ion etching and isotropic plasma etching is the etching direction. Reactive ion etching is characterized by a ratio of vertical etching rate to lateral etching rate greater than 1. Systems for reactive ion etching are built around a durable vacuum chamber. Before starting the etching process, the chamber is evacuated to a base pressure of less than 1 Torr, 100 mTorr, 20 mTorr, 10 mTorr, or 1 mTorr. Electrodes hold the material to be processed and are electrically isolated from the vacuum chamber. The electrodes may be rotatable electrodes in the shape of a cylinder. A counter electrode is also disposed within the chamber and may be formed from the wall of the vacuum reactor. A gas containing an etchant enters the chamber through a control valve. The chamber gas is continuously evacuated by a vacuum pump to maintain the process pressure. The type of gas used depends on the etching process. Carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), octafluoropropane (C3F8), trifluoromethane (CHF3), boron trichloride (BCl3), hydrogen bromide (HBr), chlorine, argon and oxygen are typically used for etching. RF power is applied to the electrode to generate a plasma. The sample can be transported on the electrode by the plasma for a controlled period of time to achieve a specified etching depth. Reactive ion etching is known in the art and is further described in US 8,460,568 (David et al.); the document is incorporated herein by reference. The gas used to generate the etching plasma typically includes oxygen and a fluorocarbon (e.g., CF4, C2F6 or C3F8). The molar concentration of the fluorocarbon gas in the mixture is typically 0% to 60%, depending on the specific type of fluorocarbon and the composition of the (co)polymer layer to be removed. Argon can also be used as an available gas, which is combined with at least one of oxygen or fluorocarbon to perform plasma etching. In some embodiments, only oxygen is used to generate the etching plasma. Typically, for plasma etching, the applicable power density range is about 0.05 W / cm2. 2 ) to about 1 watt per square centimeter.

[0178] In some cases, the transfer article is a transfer article according to the second aspect, and the outer major surface of the transfer article comprises a major surface of the first (co)polymer layer.

[0179] In selected embodiments, the method further comprises depositing a tie layer, a substrate, or both on the second major surface of the second microstructured film. Suitable tie layers and substrates are described above.

[0180] List of exemplary embodiments

[0181] In a first embodiment, a transfer article is provided. The transfer article comprises a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The transfer article further comprises: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on a major surface of the release layer opposite the microstructured film; and a multilayer optical film disposed on a major surface of the (co)polymer layer opposite the release layer. The multilayer optical film is composed of one or more alternating first and second inorganic optical layers, which together reflect and absorb light normally incident on the first major surface of the microstructured film, and reflect and absorb an average of at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0182] In a second embodiment, a transfer article according to the first embodiment is provided, wherein the microstructured film comprises polyethylene terephthalate (PET), cured polysiloxane, silicone thermoplastic polymer, cured polyurethane, thermoplastic polyurethane, cured (meth)acrylate, cured epoxy resin, cured vinyl ether, cured oxetane, cured thiol acrylate, cured thiol ene, polypropylene, polyethylene, PMMA, coPMMA, polyimide, cycloolefin copolymer, cycloolefin polymer, polycarbonate, polyethylene naphthalate (PEN) or fluoropolymer (co)polymer, wherein the fluoropolymer (co)polymer comprises polymerized units derived from one or more monomers, and the one or more monomers are selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, perfluoroalkoxyalkylene, or vinyl fluoride, or a combination thereof.

[0183] In a third embodiment, a transfer article according to the first embodiment or the second embodiment is provided, wherein the (co)polymer layer is a first (co)polymer layer, and wherein the transfer article further comprises a second (co)polymer layer disposed between the microstructured film and the release layer.

[0184] In a fourth embodiment, a transfer article according to the third embodiment is provided, wherein at least one of the first (co)polymer layer or the second (co)polymer layer comprises a (co)polymer selected from olefin (co)polymers, (meth)acrylate (co)polymers, polyurethane (co)polymers, fluoropolymers, silicone (co)polymers, or combinations thereof.

[0185] In a fifth embodiment, a transfer article according to any one of the first to fourth embodiments is provided, wherein the release layer includes a metal layer, which contains at least one selected from the group consisting of a single metal, two or more metals as a mixture, an intermetallic compound or alloy, a semimetal or a metalloid, a metal oxide, a metal and mixed metal oxide, a metal and mixed metal fluoride, a metal and mixed metal nitride, a metal and mixed metal carbide, a metal and mixed metal carbonitride, a metal and mixed metal oxynitride, a metal and mixed metal boride, a metal and mixed metal boron oxide, a metal and mixed metal silicide, diamond-like carbon, diamond-like glass, graphene, and combinations thereof.

[0186] In a sixth embodiment, a transfer article according to any one of the first to fifth embodiments is provided, wherein the release layer comprises copper oxide or silicon aluminum oxide.

[0187] In a seventh embodiment, a transfer article according to any one of the first to sixth embodiments is provided, wherein the plurality of microstructures have an aspect ratio of height to width of no greater than 10:1, 8:1, 6:1, 4:1, 2:1, or 1:1.

[0188] In an eighth embodiment, a transfer article according to any one of the first to seventh embodiments is provided, wherein at least some of the microstructures include at least one angled sidewall having a peak angle of 90 degrees or less and 5 degrees, 15 degrees, 25 degrees, 35 degrees, or 45 degrees or greater.

[0189] In a ninth embodiment, a transfer article according to any one of the first to eighth embodiments is provided, wherein the surfaces each have the same slope, the slope of the surface being such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection.

[0190] In a tenth embodiment, a transfer article according to any one of the first to ninth embodiments is provided, wherein at least some of the microstructures have a shape with a triangular cross-section.

[0191] In an eleventh embodiment, a transfer article according to any one of the first to tenth embodiments is provided, wherein the microstructure has a shape of a prism, a pyramid, an inverted pyramid, a diffraction grating, an inverted cone, or a cone.

[0192] In a twelfth embodiment, a transfer article according to any one of the first to eleventh embodiments is provided, wherein the microstructures have a height of 0.5 micrometers to 500 micrometers.

[0193] In a thirteenth embodiment, a transfer article according to any one of the first to twelfth embodiments is provided, wherein each of the first inorganic optical layer and the second inorganic optical layer independently has a thickness of 20 nm to 400 nm.

[0194] In a fourteenth embodiment, a transfer product according to any one of the first to thirteenth embodiments is provided, wherein the first optical layer comprises at least one of niobium oxide, titanium oxide, silicon oxynitride, molybdenum oxide, tungsten oxide, silicon nitride, indium tin oxide, hafnium oxide, tantalum oxide, zirconium oxynitride, zirconium oxide, zinc aluminum oxide, or zinc oxide, and wherein the second optical layer comprises at least one of silicon oxide, silicon aluminum oxide, N-type or P-type doped silicon oxide, aluminum oxide, aluminum fluoride, magnesium fluoride, calcium fluoride, indium tin oxide, or zinc oxide.

[0195] In a fifteenth embodiment, a transfer structure according to any one of the first to fourteenth embodiments is provided, wherein the first optical layer comprises at least one of niobium oxide or titanium oxide, and wherein the second optical layer comprises silicon aluminum oxide.

[0196] In a sixteenth embodiment, a transfer article according to any one of the first to fifteenth embodiments is provided, wherein the multilayer optical film is formed of at least 1 first optical layer and 2 second optical layers.

[0197] In a seventeenth embodiment, a transfer article according to any one of the first to sixteenth embodiments is provided, wherein the first (co)polymer layer is substantially transparent.

[0198] In an eighteenth embodiment, an article is provided. The article includes a first microstructured film comprising a first major surface and an opposite second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the first microstructured film intersects with the first major surface or the surface of at least one other microstructure after reflection. The article further includes: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on the major surface of the release layer opposite to the first microstructured film; a multilayer optical film disposed on the major surface of the (co)polymer layer opposite to the release layer; and a second microstructured film, the second microstructured film adjacent to the major surface of the multilayer optical film opposite to the (co)polymer layer. The second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure. The multilayer optical film comprises one or more alternating first and second inorganic optical layers, the one or more alternating first and second inorganic optical layers collectively reflecting and absorbing light normally incident on the first major surface of the second microstructured film, at least 50%, 60%, 70%, 80%, 90%, or 95% of incident ultraviolet light within a wavelength reflection bandwidth of at least 30 nm within a wavelength range of 190 nanometers (nm) to 400 nm, on average.

[0199] In a nineteenth embodiment, an article according to the eighteenth embodiment is provided, wherein the second microstructured film comprises a cured polysiloxane, a silicone thermoplastic polymer, polyethylene terephthalate (PET), a cured polyurethane, a thermoplastic polyurethane, a cured (meth)acrylate, PMMA, coPMMA, a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, polyethylene naphthalate (PEN), or a fluoropolymer (co)polymer comprising polymerized units derived from one or more monomers selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, or vinyl fluoride, or a combination thereof.

[0200] In a twentieth embodiment, there is provided an article according to the eighteenth embodiment or the nineteenth embodiment, wherein the second microstructured film comprises cured polyurethane, cured (meth)acrylate, coPMMA, PMMA, or a combination thereof, and the second microstructured film optionally further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

[0201] In a twenty-first embodiment, an article according to the eighteenth or nineteenth embodiment is provided, wherein the second microstructured film comprises a cured polysiloxane, a silicone thermoplastic polymer, or a combination thereof.

[0202] In a twenty-second embodiment, an article according to any one of embodiments eighteen to twenty-first is provided, wherein the (co)polymer layer is a first (co)polymer layer, and wherein the article further comprises a second (co)polymer layer disposed between the first microstructured film and the release layer.

[0203] In a twenty-third embodiment, an article according to any one of the eighteenth to twenty-second embodiments is provided, further comprising an adhesive layer, a substrate, or both disposed on a major surface of the second microstructured film opposite the multilayer optical film.

[0204] In a twenty-fourth embodiment, an article according to any one of the eighteenth to twenty-third embodiments is provided, wherein the second microstructured film is directly adjacent to the multilayer optical film.

[0205] In a twenty-fifth embodiment, another article is provided. The article includes a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection. The article also includes a multilayer optical film disposed on the plurality of microstructures and a (co)polymer layer disposed on a major surface of the multilayer optical film opposite the microstructured film. The multilayer optical film is composed of one or more alternating first and second inorganic optical layers, which together reflect and absorb light normally incident on the first major surface of the microstructured film, and reflect and absorb an average of at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

[0206] In a twenty-sixth embodiment, an article according to the twenty-fifth embodiment is provided, further comprising an adhesive layer, a substrate, or both disposed on the second major surface of the microstructured film.

[0207] In a twenty-seventh embodiment, an article according to the twenty-fifth embodiment or the twenty-sixth embodiment is provided, which transmits light normally incident on the first major surface of the second microstructured film, and transmits an average of at least 50%, 60%, 70%, 80%, 90% or 95% of the normally incident visible light in the wavelength range from greater than 400 nm to 700 nm.

[0208] In a twenty-eighth embodiment, there is provided an article according to any one of the twenty-fifth to twenty-seventh embodiments, wherein upon exposure to a dose of 425 megajoules per square meter (MJ / m 2 ) after exposure to ultraviolet light, the average transmittance of wavelengths between 400 nm and 700 nm through the article decreases by less than 20%, less than 10%, less than 5%, or less than 1%.

[0209] In a twenty-ninth embodiment, another transfer article is provided. The transfer article comprises a microstructured film comprising a first major surface and an opposite second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom. At least some of the plurality of microstructures each have a surface having a slope such that light normally incident on the first major surface of the microstructured film intersects with the first major surface or the surface of at least one other microstructure after reflection. The transfer article further comprises: a release layer disposed on the plurality of microstructures, wherein the release layer comprises a metal layer or a doped semiconductor layer; and a (co)polymer layer disposed on the major surface of the release layer opposite the microstructured film, wherein the (co)polymer layer further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

[0210] In a thirtieth embodiment, a transfer article according to the twenty-ninth embodiment is provided, wherein the (co)polymer layer is a first (co)polymer layer, and wherein the transfer article further comprises a second (co)polymer layer disposed between the microstructured film and the release layer.

[0211] In a thirty-first embodiment, a method of making an article is provided. The method comprises obtaining a transfer article according to any one of the first to seventeenth embodiments, the twenty-ninth embodiment, or the thirtieth embodiment; depositing a polymeric material or a cross-linkable material on an outer major surface of the transfer article opposite the first microstructured film; curing the polymeric material or the cross-linkable material to form a second microstructured film; and removing the release layer from the transfer article. The second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface with a slope such that light normally incident on the first major surface of the second microstructured film intersects the first major surface or a surface of at least one other microstructure after reflection, and wherein the first major surface of the second microstructured film is adjacent to the multilayer optical film.

[0212] In a thirty-second embodiment, a method according to the thirty-first embodiment is provided, wherein the transfer article is a transfer article according to any one of the first to seventeenth embodiments, and the outer major surface of the transfer article includes the major surface of the multilayer optical film opposite to the first (co)polymer layer.

[0213] In a thirty-third embodiment, a method according to the thirty-first embodiment or the thirty-second embodiment is provided, wherein the transfer article is a transfer article according to any one of the first to seventeenth embodiments, and the method further includes removing the first (co)polymer layer after removing the peel layer.

[0214] In a thirty-fourth embodiment, a method according to the thirty-third embodiment is provided, wherein the first (co)polymer layer is removed using etching.

[0215] In a thirty-fifth embodiment, a method according to the thirty-first embodiment is provided, wherein the transfer article is a transfer article according to the twenty-ninth embodiment or the thirtieth embodiment, and the outer major surface of the transfer article includes the major surface of the first (co)polymer layer.

[0216] In a thirty-sixth embodiment, a method according to any one of embodiments thirty-first to thirty-fifth is provided, further comprising depositing a tie layer, a substrate, or both on the second major surface of the second microstructured film.

[0217] Example

[0218] Unless otherwise indicated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight.

[0219]

[0220]

[0221] Test Method

[0222] Spectral characteristic modeling test : Before making an article, the optical properties (transmission, reflection, and absorption) of the intended inorganic coating are modeled to accurately determine the necessary thickness of the optical coating. To perform this modeling, Test Samples 1 and 2 were measured using an ellipsometer (available from J.A. Woolam, Lincoln, NE, under the trade designation "RC2 Ellipsometer") to determine the spectral refractive index (n) and extinction coefficient (k) values of the evaporated TiO2 and SiO2 samples. The n and k obtained above were then entered into optical modeling software (available from The Thin Film Center, Tucson, AZ, under the trade designation "Essential MacLeod") and used to calculate the reflection, transmission, and absorption spectra of the multilayer optical films prepared as described below. All structures were modeled with a PET substrate at an incident angle of 45 degrees with the highest numbered oxide layer of the coating facing the air. The SR833 and silicone layers were not included in the modeling. In the Reflection and Absorption Results tables and the Transmission Results table, the results of the reflection, absorption, and transmission modeling are reported as average percentages over the wavelength range. Note that the modeling calculates the transmission, reflection, and absorption of the inorganic optical coating only; the modeling does not calculate the absorption of the substrate material or the back surface reflection.

[0223] Spectral characteristics measurement test Spectral transmission and reflectance of individual examples of the articles were measured using a spectrophotometer (available from PerkinElmer, Inc., Waltham, MA under the trade designation "LAMBDA 1050"). Absorbance (in percent) was calculated as 100 - reflectance - transmittance. In the Reflectance and Absorption Results tables and the Transmission Results table, the measured spectral reflectance, absorbance, and transmittance are reported as average percentages over the wavelength range.

[0224] Sun aging testThe samples were exposed in an Atlas Ci5000 Weathering Tester (available from AMETEK, Berwyn, PA) using a xenon arc lamp equipped with quartz inner and outer filters. The xenon lamp gives a close approximation to the shape of the solar output (ASTM E490), and the quartz filter set provides minimal attenuation of the xenon lamp's spectral power distribution. The samples were exposed on a custom stainless steel and aluminum holder. The exposure plane was 19 inches (48.3 cm) from the lamp wick. The irradiance was controlled at 1.3 watts per square meter (W / m2) at 340 nm on the holder. 2 The ambient air temperature inside the weathering tester was controlled at 47°C, the black panel thermometer (BPT) was controlled at 70°C on the support plane and the relative humidity was controlled at 30%. The samples were exposed to an aluminum plate as a backing. The samples were exposed to a cumulative irradiance of 250nm-385nm with a dose of at least 425 megajoules / square meter (MJ / m 2 ).

[0225] The change in transmittance is calculated as:

[0226]

[0227] Where T fresh is the average transmittance from 400nm to 700nm before solar aging, and T aged is the average transmittance from 400nm to 700nm after the above exposure. The results of the solar aging test are summarized in the solar aging results table.

[0228] Transfer testing : A transfer test was used to determine whether a multilayer optical film could be transferred from being attached (directly or indirectly) to one microstructured substrate to being attached to another microstructured substrate, i.e., to determine, for a given article having a first microstructured film and a second microstructured film, with the multilayer optical film disposed between the first and second microstructured films (optionally with one or more additional layers also positioned therebetween), whether the first and second microstructured films could be separated such that the multilayer optical film was transferred from being attached to the first microstructured film to being attached to the second microstructured film. For this test, we started with the article of Example 3, Example 6, or Comparative Example 1.

[0229] An attempt to separate the first and second microstructured films was performed using the following method. First, a new razor blade was used to cut into the second microstructured film side of the article. The cut defined a rectangular area that was smaller than the original piece of the article and large enough to enable subsequent characterization. For example, a 2-inch by 2-inch (5.08 cm x 5.08 cm) starting piece of the article was used and a 1.5-inch by 1.5-inch (3.81 cm x 3.81 cm) area was cut out, which was large enough for spectroscopic characterization. When cutting out this area, care was taken to cut completely through the second microstructured film and into the first microstructured film without cutting completely through the first microstructured film. Next, the article was placed on a workbench with the first microstructured surface facing down and the second microstructured film side facing up, and the corners of the second microstructured film were taped down to the workbench with 3M polyester tape by placing tape on the second microstructured film surface and the workbench. The corners were taped to the workbench to prevent the substrate from lifting during the separation operation. Next, a piece of 3M polyester tape was placed over one edge of the rectangular cut area of the second microstructured film, such that the 3M polyester tape extended only 1 centimeter (cm) into the rectangular area. The tape was then used as a mechanical handle to attempt to pull and separate the second microstructured film from the first microstructured film. The results of the separation attempt were qualitatively recorded, such as "unable to separate the first and second microstructured films," "films successfully separated," etc. If separation was possible, the separated piece of the second microstructured film was then characterized to determine whether transfer of the multilayer optical film occurred (i.e., by measuring the optical properties of the film to look for optical signatures of the multilayer optical film), and the results of the characterization were qualitatively reported, such as the presence / absence of optical signatures of the vapor-coated multilayer film on the second microstructured film. The results of the transfer test are reported in the Transfer Test Results table below.

[0230] Test samples

[0231] Test Sample 1: A 70 nm thick TiO2 layer was deposited on a silicon wafer as follows: The vapor coater used was a Denton Vacuum optical coater consisting of a 5-planetary gear drive system located approximately 30" (76.2 cm) above a 4-pocket Temescal electron beam gun (available from Ferro Tec Corporation, Livermore, CA). The planetary gear drive system was designed to hold the substrate perpendicular to the evaporation source and move the disc in and out of the evaporation plume in a planetary motion during deposition. The actual coating process involved: a) venting the vapor coater to atmosphere and removing one of the five planets. The substrate was prepared for coating by adhering / wrapping the substrate to the planet using polyimide tape. b) reinstalling the planet and, if desired, similarly constructing the other 4 planets and reinstalling them in the coater. c) sealing the chamber and pumping it down to <2x10 -5 Support (2.7x10 -3 d) While the vapor coater was under sufficiently low vacuum, the material was ion beam treated using a Kaufman-type ion source at 400 V for about 10 minutes as a pretreatment of the substrate to adhere the vapor deposited coating to the substrate prior to application of the oxide film. e) Oxygen was added via an MKS mass flow controller (available from MKS Instruments, Inc., Andover, MA) to obtain a 4.0 x 10 -5 Support(5.3x10 -3The coating is then heated to a pressure of 100 Pa (Pa). The oxygen added is typically about 10 standard cubic centimeters per minute (sccm). f) The planetary gear is started and moved around the coater at a rotational speed of about 60 rpm to prepare for coating and achieve a high level of uniformity on the attached substrate. g) The Temescal electron beam gun power supply is powered on. A voltage of 10 kV and a current of several milliamperes are applied to the filament of the electron gun, thereby heating the source material in the electron gun. The source is heated and controlled by an Eddy Optical Monitoring System (OMS) (purchased from Eddy Company, Apple Valley, CA). The source is heated until the desired deposition rate for the material is achieved; in the case of TiO2, the rate is 2 angstroms per second, and in the case of SiO2, the rate is 4 angstroms per second. When the desired deposition rate for the material is achieved and remains stable, the gate separating the source from the planetary gear is opened and the rate is maintained by the OMS until the desired optical thickness is achieved, at which point the gate is closed and the OMS cuts off power to the electron beam source. h) Turn off the main power to the power source and allow the source to cool for approximately 10 minutes. i) Repeat this process for additional layers / types of material until all desired multilayer optical films have been deposited. j) The chamber is then vented back to atmospheric pressure via N2 gas, and each planet is removed and the substrate removed from each planet.

[0232] Test Sample 2: SiO2 with a thickness of 115 nm was deposited on a silicon chip in the same manner as Test Sample 1.

[0233] Example

[0234] Example 1 :

[0235] Transferable structured acrylates were produced on a roll-to-roll vacuum coater similar to the one described in U.S. Patent Application No. 2010 / 0316852 (Condo et al.), by adding a second evaporator and curing system between the plasma pretreatment station and the first sputtering system, and using an evaporator as described in U.S. Patent No. 8,658,248 (Anderson et al.). The coater was equipped with a substrate in the form of an indefinite-length roll of 0.05 mm thick, 14-inch (35.6 cm) wide BEF4, oriented so that the microstructured surface of the BEF4 would be exposed to the treatment / coating process. The BEF4 was prepared for coating by subjecting it to a nitrogen plasma treatment to improve the adhesion of the copper oxide (CuOx) layer on the BEF4 surface. The nitrogen plasma treatment of the film was operated at 20 W using a titanium cathode, using a web speed of 34 fpm (10.3 meters / minute) and maintaining the back of the film in contact with the coating drum cooled to 0°C. On the surface of the nitrogen plasma-treated BEF4 substrate, a lift-off layer of CuOx was deposited in a second pass. CuOx deposition used a conventional direct current (DC) sputtering process with a Cu target operating at 1 kW power, at a line speed of 3 fpm (0.9 m / min) in the sputtering zone, with 120 sccm of O2 and 450 sccm of Ar deposited onto the substrate. The CuOx-coated BEF4 substrate was then rewound.

[0236] In three passes at a line speed of 17 fpm, an estimated thickness of 500 nm of SR833 acrylate layer was formed on top of the CuOx layer. The acrylate layer was applied by ultrasonic atomization and flash evaporation to a coating width of 12.5 inches (31.8 cm). The flow rate of SR833 into the atomizer was 1.33 mL / min, the N2 carrier gas flow rate was 60 sccm, and the evaporator temperature was 260°C. Once condensed onto the CuOx layer, the monomer coating was immediately cured using an electron beam curing gun operated at 7.0 kV and 4.0 mA.

[0237] After removing BEF4 from the vacuum, 3M vinyl tape was manually laminated using a 3M-71601 rigid plastic scraper to ensure that the vinyl adhesive was in contact with the entire structured SR833 acrylate layer. Peeling the adhesive by hand confirmed that the acrylate layer could be completely removed from the CuOx layer, which remained well bonded to BEF4.

[0238] Example 2 :

[0239] A vapor-coated multilayer optical film was prepared in the same manner as Test Sample 1, except that the Example 1 film was used as the substrate and the structures deposited on the Example 1 substrate are summarized in the Example Structures table below. The Example 1 substrate was taped to the planet so that the structured / coated side of Example 1 would be coated by the vapor coating process.

[0240] An important factor to consider when preparing vapor-phase coatings on microstructured substrates is the geometry of the substrate. The slope of the structures will increase the surface area of the microstructured substrate relative to a planar substrate. Due to the increased surface area, the same material deposition process on a microstructured substrate and a planar substrate will produce a thinner coating on the surface of the microstructured substrate than on the planar substrate. In other words, a fixed deposition process deposits a fixed volume of material onto the substrate, so substrates with a higher surface area will generally receive a thinner coating (the coating thickness is equal to the volume of material deposited divided by the surface area of the substrate).

[0241] Therefore, to achieve a specific thickness on a microstructured substrate, the total volume of the deposited material must be increased. The factor by which the material volume is increased should be equal to the ratio of the surface areas of the microstructured substrate to the planar substrate. In the case of the Example 1 substrate, which has one-dimensional prisms with a peak angle of 90 degrees and therefore a slope of 45 degrees, the volume of the deposited material needs to be increased by a factor equal to 1 / SIN(peak angle / 2) = 1 / SIN(45°) = 1.414.

[0242] Example 3 :

[0243] A layer of Sylgard 184 curable silicone elastomer is applied to the sheet of Example 2 and cured. Sylgard 184 curable silicone is prepared and applied as follows: Sylgard 184 processing, mixing, handling, etc., all of which are performed under ambient conditions. Sylgard 184 silicone elastomer base and Sylgard 184 silicone elastomer curing agent are poured together into a glass jar at a mass ratio of base:curing agent of 10:1. The material is mixed with a wooden tongue depressor for one minute, taking care to avoid air entrapment. The mixture is allowed to stand for 1 hour to allow the trapped air to escape. The mixture is then slowly poured onto the center of the sheet of Example 2 until the entire sheet is covered with Sylgard 184. Sylgard 184 is then allowed to cure for 48 hours under ambient conditions.

[0244] Example 4 :

[0245] Cured prismatic Sylgard 184 silicone elastomer with a transferred vapor coating was prepared by taking the sheet of Example 3 after the Sylgard 184 had fully cured and then peeling the film substrate from the Sylgard 184 coating. Peeling the silicone from the substrate was accomplished by using a razor blade to cut out the desired area of the film to be peeled, being careful to cut only the silicone layer and not the substrate. The corners of the substrate were taped down to a workbench with 3M polyester tape to prevent the substrate from lifting during the peeling operation. A piece of 3M polyester tape was then placed over one edge of the silicone in the area to be peeled, so that the 3M polyester tape did not cover the entire area to be peeled, and the tape was then used as a mechanical handle to peel the silicone from the substrate. The tape was pulled in a direction orthogonal to the length of the prismatic features of the BEF4 substrate; in other words, from peak to peak. This operation releases the SR833 layer from the CuOx layer, resulting in a microstructured Sylgard 184 film coated with SiO2, TiO2, and SR833 layers according to the following example structure table.

[0246] Example 5 :

[0247] Example 5 was prepared in the same manner as Example 2, except that the layers were used as described in the Example Structure Table.

[0248] Example 6 :

[0249] Example 6 was prepared in the same manner as Example 3, with the following changes: instead of using the film of Example 2 as the substrate, the film of Example 5 was used as the substrate; and DC 93-500 was used instead of Sylgard 184. DC 93-500 curable silicone was prepared and applied as follows: DC 93-500 processing, mixing, handling, etc., all of which were performed under ambient conditions. DC 93-500 silicone elastomer base and DC 93-500 silicone elastomer curing agent were poured together into a glass jar at a mass ratio of base:curing agent of 10:1. The materials were mixed with a wooden tongue depressor for one minute, taking care to avoid air entrapment. The mixture was allowed to stand for 1 hour to allow trapped air to escape. The mixture was then slowly poured onto the center of the sheet of Example 5 until the entire sheet was covered with DC 93-500. The DC 93-500 was then allowed to cure under ambient conditions for 48 hours.

[0250] Example 7 :

[0251] Example 7. A cured prismatic DC 93-500 silicone elastomer with a transferred vapor coating was prepared by taking the sheet of Example 6 after the DC 93-500 had fully cured and peeling the film substrate from the DC 93-500 silicone coating. Peeling the silicone from the substrate was accomplished by using a razor blade to cut out the desired area of the film to be peeled, being careful to cut only the silicone layer and not the substrate. The corners of the substrate were taped down to the workbench with 3M polyester tape to prevent the substrate from lifting during the peeling operation. A piece of 3M polyester tape was then placed over one edge of the silicone in the area to be peeled, so that the 3M polyester tape did not cover the entire area to be peeled, and the tape was then used as a mechanical handle to peel the silicone from the substrate. The tape was pulled in a direction perpendicular to the length of the BEF4 substrate's prismatic features; in other words, in the prism-peak-to-peak direction. This operation releases the SR833 layer from the CuOx layer, resulting in a microstructured DC 93-500 film coated with SiO2, TiO2, and SR833 layers according to the following example structure table.

[0252] Comparative Example 1

[0253] Comparative Example 1 was prepared by first depositing a vapor-coated multilayer optical film in the same manner as Example 2, but using a BEF4 sheet as the substrate instead of the sheet of Example 1. The structure of the vapor-coated multilayer optical film can be found in layers 1-11 in the Comparative Example Structures table. A layer of DC 93-500 curable silicone elastomer was then coated and cured onto the outer surface (layer 12) of the vapor-coated multilayer optical film in the same manner as used to coat and cure the DC 93-500 layer in Example 6.

[0254] Comparative Example 2

[0255] Comparative Example 2 is a piece of BEF4 film.

[0256] Example Structure Table

[0257] Layer 1 is in contact with the substrate.

[0258]

[0259]

[0260] Comparative Example Structure Table

[0261] Layer 1 is in contact with the substrate.

[0262] sample Comparative Example 1 Comparative Example 2 base BEF4 BEF4 Layer 1 <![CDATA[SiO2 / 55.1nm]]> Layer 2 <![CDATA[TiO2 / 31.6nm]]> Layer 3 <![CDATA[SiO2 / 55.1nm]]> Layer 4 <![CDATA[TiO2 / 37.2nm]]> Layer 5 <![CDATA[SiO2 / 55.1nm]]> Layer 6 <![CDATA[TiO2 / 37.2nm]]> Layer 7 <![CDATA[SiO2 / 55.1nm]]> Layer 8 <![CDATA[TiO2 / 37.2nm]]> Layer 9 <![CDATA[SiO2 / 55.1nm]]> Layer 10 <![CDATA[TiO2 / 31.6nm]]> Layer 11 <![CDATA[SiO2 / 140.8nm]]> Layer 12 DC 93-500

[0263] Reflection and Absorption Results Table

[0264]

[0265] Transmission results table

[0266]

[0267] Sun Aging Results Table

[0268]

[0269] Transfer Test Results Table

[0270]

[0271] Although specific embodiments have been illustrated and described herein, those skilled in the art will appreciate that a variety of alternative and / or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Accordingly, the present disclosure is intended to be limited only by the claims and their equivalents.

[0272] In addition, all publications and patents cited herein are incorporated by reference in their entirety, just as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In the event of any inconsistency or conflict between an incorporated reference and this application, the information in the foregoing description will control. Various exemplary embodiments have been described. These and other embodiments are within the scope of the following claims.

Claims

1. A transfer article, comprising: a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or a surface of at least one other microstructure; a peeling layer, the peeling layer being disposed on the plurality of microstructures, wherein the peeling layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on a major surface of the release layer opposite the microstructured film; and A multilayer optical film, the multilayer optical film being disposed on a major surface of the (co)polymer layer opposite to the release layer, wherein the multilayer optical film comprises one or more alternating first inorganic optical layers and second inorganic optical layers, the one or more alternating first inorganic optical layers and second inorganic optical layers jointly reflecting and absorbing light normally incident on the first major surface of the microstructured film, and reflecting and absorbing at least 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300%, 310%, 320%, 330%, 340%, 350%, 360%, 370%, 380%, 390%, 400%, 400%, 410%, 420%, 430%, 440%, 450%, 460%, 470%, 480%, 490%, 500%, 510%, 520%, 530%, 540%, 550%, 560%, 570%, 580%, 590%, 600%, 610%, 620%, 630%, 640%, 650%, 660%, 670%, 680%, 700%, 710%, 720%, 730%, 740%, 750%, 760%, 770%, 780%, 790%, 800%, 800%, 800%, 800%, 800%, 800%, 800%, 800%, 800%, 80%, 90% or 95% of the incident UV light.

2. The transfer article of claim 1 , wherein the microstructured film comprises polyethylene terephthalate (PET), a cured polysiloxane, a silicone thermoplastic polymer, a cured polyurethane, a thermoplastic polyurethane, a cured (meth)acrylate, a cured epoxy resin, a cured vinyl ether, a cured oxetane, a cured thiol acrylate, a cured thiol ene, polypropylene, polyethylene, PMMA, coPMMA, a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, polyethylene naphthalate (PEN), or a fluoropolymer (co)polymer comprising polymerized units derived from one or more monomers selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, a perfluoroalkoxyalkylene, or vinyl fluoride, or a combination thereof.

3. The transfer article according to claim 1 or 2, wherein the (co)polymer layer is a first (co)polymer layer, and wherein the transfer article further comprises a second (co)polymer layer disposed between the microstructured film and the release layer.

4. A transfer article according to claim 3, wherein at least one of the first (co)polymer layer or the second (co)polymer layer comprises a (co)polymer, and the (co)polymer is selected from olefin (co)polymers, (meth)acrylate (co)polymers, polyurethane (co)polymers, fluoropolymers, silicone (co)polymers, or combinations thereof.

5. The transfer article according to any one of claims 1 to 4, wherein the release layer comprises a metal layer comprising at least one member selected from the group consisting of a single metal, two or more metals as a mixture, an intermetallic compound or alloy, a semimetal or metalloid, a metal oxide, a metal and mixed metal oxide, a metal and mixed metal fluoride, a metal and mixed metal nitride, a metal and mixed metal carbide, a metal and mixed metal carbonitride, a metal and mixed metal oxynitride, a metal and mixed metal boride, a metal and mixed metal boron oxide, a metal and mixed metal silicide, diamond-like carbon, diamond-like glass, graphene, and combinations thereof. 6 . The transfer article according to claim 1 , wherein the release layer comprises copper oxide or silicon aluminum oxide.

7. A transfer article according to any one of claims 1 to 6, wherein at least some of the microstructures include at least one angled sidewall having a peak angle of 90 degrees or less and 5 degrees, 15 degrees, 25 degrees, 35 degrees or 45 degrees or greater.

8. The transfer article of any one of claims 1 to 7, wherein each of the surfaces has the same slope, the slope of the surface being such that light normally incident on the first major surface of the microstructured film intersects the first major surface or the surface of at least one other microstructure after reflection.

9. The transfer article according to any one of claims 1 to 8, wherein at least some of the microstructures have a shape with a triangular cross-section.

10. The transfer article according to any one of claims 1 to 9, wherein the microstructure has a shape of a prism, a pyramid, an inverted pyramid, a diffraction grating, an inverted cone, or a cone.

11. The transfer article of any one of claims 1 to 10, wherein each of the first inorganic optical layer and the second inorganic optical layer independently has a thickness of 20 nm to 400 nm.

12. The transfer article according to any one of claims 1 to 11, wherein the first optical layer comprises at least one of niobium oxide, titanium oxide, silicon oxynitride, molybdenum oxide, tungsten oxide, silicon nitride, indium tin oxide, hafnium oxide, tantalum oxide, zirconium oxynitride, zirconium oxide, zinc aluminum oxide, or zinc oxide, and wherein the second optical layer comprises at least one of silicon oxide, silicon aluminum oxide, N-type or P-type doped silicon oxide, aluminum oxide, aluminum fluoride, magnesium fluoride, calcium fluoride, indium tin oxide, or zinc oxide.

13. An article comprising: a first microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface includes a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the first microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure; a peeling layer, the peeling layer being disposed on the plurality of microstructures, wherein the peeling layer comprises a metal layer or a doped semiconductor layer; a (co)polymer layer disposed on a major surface of the release layer opposite the first microstructured film; a multilayer optical film disposed on a major surface of the (co)polymer layer opposite the release layer; and a second microstructured film adjacent a major surface of the multilayer optical film opposite the (co)polymer layer, wherein the second microstructured film comprises a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure; The multilayer optical film comprises one or more alternating first and second inorganic optical layers, which together reflect and absorb light normally incident upon the first major surface of the second microstructured film, and reflect and absorb, on average, at least 50%, 60%, 70%, 80%, 90% or 95% of the incident ultraviolet light within a reflection bandwidth of at least 30 nanometers in the wavelength range of 190 nanometers (nm) to 400 nm.

14. The article of claim 13, wherein the second microstructured film comprises a cured polysiloxane, a silicone thermoplastic polymer, polyethylene terephthalate (PET), a cured polyurethane, a thermoplastic polyurethane, a cured (meth)acrylate, a cured epoxy, a cured vinyl ether, a cured oxetane, a cured thiol acrylate, a cured thiol ene, PMMA, coPMMA, a polyimide, a cyclic olefin copolymer, a cyclic olefin polymer, a polycarbonate, polyethylene naphthalate (PEN), or a fluoropolymer (co)polymer comprising polymerized units derived from one or more monomers selected from tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, a perfluoroalkoxyalkylene, or vinyl fluoride, or a combination thereof.

15. The article of claim 13 or 14, wherein the second microstructured film comprises cured polyurethane, cured (meth)acrylate, coPMMA, PMMA, or a combination thereof, and the second microstructured film optionally further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

16. The article of claim 13 or 14, wherein the second microstructured film comprises a cured polysiloxane, a silicone thermoplastic polymer, or a combination thereof.

17. The article of any of claims 13 to 16, further comprising an adhesive layer, a substrate, or both disposed on a major surface of the second microstructured film opposite the multilayer optical film.

18. An article comprising: a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure; a multilayer optical film disposed on the plurality of microstructures, wherein the multilayer optical film comprises one or more alternating first and second inorganic optical layers that collectively reflect and absorb, on average, at least 50%, 60%, 70%, 80%, 90%, or 95% of incident ultraviolet light within a reflection bandwidth of at least 30 nm over a wavelength range of 190 nanometers (nm) to 400 nm when incident upon the first major surface of the microstructured film; and A (co)polymer layer is disposed on a major surface of the multilayer optical film opposite the microstructured film.

19. The article of claim 18, further comprising an adhesive layer, a substrate, or both disposed on the second major surface of the microstructured film.

20. The article of claim 18 or 19, which transmits light normally incident on the first major surface of the second microstructured film, and transmits an average of at least 50%, 60%, 70%, 80%, 90% or 95% of the normally incident visible light in the wavelength range from greater than 400 nm to 700 nm.

21. The article of any one of claims 18 to 20, wherein the 2 ) after exposure to ultraviolet light, the average transmittance of wavelengths between 400 nm and 700 nm through the article decreases by less than 20%, less than 10%, less than 5%, or less than 1%.

22. A transfer article comprising: a microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure; a peeling layer, the peeling layer being disposed on the plurality of microstructures, wherein the peeling layer comprises a metal layer or a doped semiconductor layer; A (co)polymer layer is disposed on a major surface of the release layer opposite the microstructured film, wherein the (co)polymer layer optionally further comprises an ultraviolet radiation absorber, a hindered amine light stabilizer, an antioxidant, or a combination thereof.

23. The transfer article of claim 22, wherein the (co)polymer layer is a first (co)polymer layer, and wherein the transfer article further comprises a second (co)polymer layer disposed between the microstructured film and the release layer.

24. A method of manufacturing an article, the method comprising: Obtaining a transfer article according to any one of claims 1 to 12, 22 or 23; depositing a polymeric or cross-linkable material on an outer major surface of the transfer article opposite the first microstructured film; curing the polymeric or cross-linkable material to form a second microstructured film comprising a first major surface and an opposing second major surface, wherein the first major surface comprises a plurality of microstructures protruding therefrom, wherein at least some of the plurality of microstructures each have a surface sloped such that light normally incident on the first major surface of the second microstructured film, after reflection, intersects the first major surface or the surface of at least one other microstructure, and wherein the first major surface of the second microstructured film is adjacent to the multilayer optical film; as well as The release layer is removed from the transfer article.

25. The method of claim 24, wherein the transfer article is a transfer article according to any one of claims 1 to 12, and the method further comprises removing the first (co)polymer layer after removing the release layer.

26. The method of claim 24 or 25, further comprising depositing a tie layer, a substrate, or both on the second major surface of the second microstructured film.

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