WO2014152962A1

WO2014152962A1 - Embossing coated polymeric film composites for optical effects

Info

Publication number: WO2014152962A1
Application number: PCT/US2014/028418
Authority: WO
Inventors: Michael W. Sullivan
Original assignee: Madico Inc
Current assignee: Madico Inc
Priority date: 2013-03-14
Filing date: 2014-03-14
Publication date: 2014-09-25
Anticipated expiration: 2015-09-14

Abstract

Embossed coated polymeric film composites and methods of making the same are described. The composites may include a polymeric film substrate and a first coating layer applied to the substrate. The first coating layer may have a lower glass transition temperature than the polymeric film substrate to facilitate embossing various optical and/or decorative effects in the first coating layer. Dyes and metallic particles may be added for additional optical and/or decorative effect. In some instances, additional layers may be added to the embossed composite to protect the composite or make it scratch-resistant, for example.

Description

EMBOSSING COATED POLYMERIC FILM COMPOSITES FOR OPTICAL EFFECTS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. Provisional Patent Application Serial No. 61/781,243, filed on March 14, 2013. Each patent and patent application cited herein is hereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The disclosure relates generally to embossing on coated polymeric film composites and, in particular, to coating polymeric film substrates with layer(s) whose properties, such as lower relative glass transition temperatures, facilitate forming features and patterns on the composites for various uses, such as for optical or decorative applications.

BACKGROUND

[0003] Forming features and patterns on substrates, such as polymeric films, can be achieved using numerous different processes. One particular process - embossing - is a process for producing raised or sunken features and/or patterns in substrates for various uses, such as optical or decorative applications. Generally, this process is performed using matched male and female roller dies or platen, or by some other pressing action. Embossing is typically accomplished using a combination of heat and pressure.

SUMMARY

[0004] The subject matter of this application may involve, in some cases, interrelated products, alternative solutions to a particular problem, and/or a plurality of different uses of a single article or method.

[0005] In one aspect, a method of embossing a coated polymeric film composite is provided, the method including applying a first coating layer to a first side of a polymeric film substrate, wherein the first coating layer has a lower glass transition temperature (T_g) than the polymeric film substrate; and embossing at least one pattern in the first coating layer. The method may include combining at least one high T_g material and at least one low T_g material to make the first coating layer. In some embodiments, the at least one high T_g material may be at least one acrylic and the at least one low T_g material may be at least one fluoropolymer. The method may further include making the first coating layer from a solution of at least one acrylic, at least one fluoropolymer, and a solvent. In some instances, the solvent may include at least one of acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, N-methyl-2- pyrrolidone (NMP), and/or dimethylacetamide (DMAC).

[0006] In some embodiments, the method may include: applying a second coating layer to the embossed first coating layer, wherein the second coating layer has a lower T_g than the first coating layer; and embossing at least one pattern in the second coating layer. In some instances, the method may include: applying a second coating layer to a second side of the polymeric film substrate, wherein the second coating layer has a lower glass transition temperature (T_g) than the polymeric film substrate; and embossing at least one pattern in the second coating layer. In one or more embodiments, the method may include: applying a metallic layer to the embossed first coating layer; applying an overlaminate layer to the metallic layer; and applying a protective layer to the overlaminate layer. The method may include applying an adhesive layer to a second side of the polymeric film substrate; and applying a release liner to the adhesive layer.

[0007] In another aspect, a coated polymeric film composite is provided, the composite including a polymeric film substrate layer; and a first coating layer applied to the polymeric film substrate, the first coating layer having a lower glass transition temperature (T_g) than the polymeric film substrate layer, wherein at least one pattern is imprinted in the first coating layer. In some embodiments, the imprinted first coating layer may provide an optical and/or decorative effect to the composite. The first coating layer may be made from a solution of at least one acrylic, at least one fluoropolymer, and a solvent. In some instances, the first coating layer may include at least one dye and/or at least one metallic deposit. The polymeric film substrate layer may be comprised of at least one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), and/or poly(methyl methacrylate) (PMMA).

[0008] In some embodiments, the T_g of the first coating layer of the composite may be in the range of 5 to 60 °C. In one or more embodiments, the first coating layer may have a thickness in the range of 1 to 200 micrometers. The at least one pattern imprinted in the first coating layer may redirect light passing through the composite. In some instances, the difference between the polymeric film substrate layer T_g and the first coating layer T_g may be at least 20 °C. In some embodiments, the first coating layer may adhere to the polymeric film substrate layer without the assistance of an additional adhesive. In some cases, the composite may include one or more additional coating layers applied to the composite, wherein the one or more additional coating layers are imprinted with at least one pattern. In some instances, the composite may include one or more additional layers applied to the composite, wherein the one or more additional layers includes at least one of an overlaminate layer, protective layer, scratch-resistant layer, adhesive layer, metallic layer, and/or dyed layer.

[0009] In another aspect, a coated polymeric film composite is provided, the composite including a polymeric film substrate layer; a first coating layer comprised of at least one acrylic and at least one fluoropolymer, wherein the first coating layer is applied to the polymeric film substrate layer and the first coating layer has a lower glass transition temperature (T_g) than the polymeric film substrate layer; and at least one pattern imprinted in the first coating layer to provide an optical and/or decorative effect to the composite. In some embodiments, the at least one pattern imprinted in the first coating layer may be on a micrometer scale.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates a flow diagram of a general embossing technique in accordance with one or more embodiments.

[0011] FIG. 2 illustrates various components of a low T_g coating layer in accordance with one or more embodiments.

[0012] FIG. 3A illustrates an exploded view of the layers of a coated polymeric film composite prior to being embossed in accordance with an embodiment.

[0013] FIG. 3B illustrates the coated polymeric film composite in FIG. 3A after the coating layer has been embossed and the additional layers have been applied.

[0014] FIG. 4A illustrates a polymeric film composite having two coating layers prior to being embossed in accordance with an embodiment.

[0015] FIG. 4B illustrates the coated polymeric film composite in FIG. 4A after the coating layers have been embossed.

[0016] FIG. 5 illustrates an embossed polymeric film composite having multiple coating layers in accordance with an embodiment. [0017] FIG. 6 is a photomicrograph of a tool having a micro-optic pattern used to emboss a polymeric film composite in accordance with an embodiment.

[0018] FIG. 7 is a photomicrograph of an embossed polymeric film composite depicting a micro-optic pattern in accordance with an embodiment.

[0019] These and other features of the present embodiments will be understood better by reading the following detailed description, taken together with the figures herein described. The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing.

DETAILED DESCRIPTION

[0020] Described herein are film composites and methods for producing film composites in which a polymer film that is inherently difficult to emboss (due to a high glass transition temperature for example) is rendered readily embossable by coating the polymer film with a second polymer that exhibits a lower glass transition temperature. The composite can then be embossed by imprinting the second polymer which can be permanently attached and indiscernible from the underlying polymer substrate. The composite can be readily embossed for functional or decorative properties while retaining the structural and physical properties of the underlying substrate.

[0021] Embossing or imprinting is a process used to achieve targeted nanometer/micrometer- scale surface features and patterns in polymeric films used in optical and decorative applications. The basic principle of embossing or imprinting is that a polymeric substrate is first heated above its glass transition temperature (T_g) and then a mold is pressed against the substrate, fully transferring the feature or pattern. Many conventional polymeric films used in these embossing processes have relatively high glass transition temperatures (T_gs), e.g., greater than 70, 100, or even 140 °C, depending upon the film composition. Further, most conventional films have inherently poor heat transfer capabilities. At least these two features result in most conventional polymeric films requiring high temperatures and/or pressures to modify the surface topography. Embossing directly onto the conventional polymeric films and other forming methods currently employed, such as the use of flame treatment, infrared (IR) panels, and pre-heating stations with a cooled (quenched) embossing pattern, cause non-trivial issues, including distortion problems, fouling of the pattern roller or platen by melted polymer, and uneven pattern deposition. Further, embossing directly on these conventional films can negatively affect both the appearance and dimensional stability of the finished product.

[0022] Thus, and in accordance with one or more embodiments, techniques are disclosed for coating substrates with one or more layers to facilitate forming patterns on composites in a more efficient, cost-effective, and/or controllable manner. Additional layers may be added to the embossed, coated substrate to create a final composite. The term "layer" as used herein in the context of applying or coating, should be understood to include both partial and complete applications and/or coatings. The term "composite" as used herein should be understood to include two or more layers (e.g., a polymeric film substrate layer, a coating layer, an overlaminate layer, etc.) combined and/or adhered in some manner (e.g., by coating, by applying with an adhesive, by applying without an adhesive, etc.), such as a polymeric film substrate having a coating layer. The term "pattern" as used herein should be understood to include individual features, such as words, symbols, parallel or concentric lines, or any other distinctive design. The techniques can be implemented, for example, to create optical and/or decorative effects on polymeric films. The embossed films may be used for various optical applications, such as optical filtering (e.g., ultraviolet blocking), optical redirecting (e.g., daylighting), and optical blocking (e.g., one-way visibility). In some embodiments, one or more layers may provide additional functionality, such as, for example, anti -reflective or anti-glare properties. The embossed film composites may include decorative effects, through the use of, for example, dyes, metal depositions, or aesthetically appealing patterns. The decorative effects may be applied to one or more layers in the composite Although example embodiments will primarily be disclosed for use with polymeric films, the techniques and concepts disclosed herein may be applied to any suitable substrate. Numerous configurations and variations will be apparent in light of this disclosure.

[0023] One or more embodiments utilize at least one coating layer to facilitate embossing on polymeric films, especially for achieving targeted nanometer/micrometer-scale surface patterns. As previously described, conventional polymeric films used in optical and decorative applications have limitations, primarily related to their high T_gs and inherently poor heat transfer capabilities. Accordingly, the at least one coating layer has a lower T_g than the polymeric film substrate it is coated on, which facilitates embossing on the films. The coating layer may be made from one or more materials whose composite T_g is lower than that of the polymeric film it coats. Imprinting features and patterns into a coating layer having a lower T_g requires lower temperatures and pressures during the embossing process, thereby requiring less energy. Imprinting into the coating layer provides consistent application of patterns on polymeric film substrates, since the characteristics of the coating layer, in addition to having a lower T_g, may be selected to prevent any stress or change to the base polymeric film. In addition, the coatings provide more options for optical and decorative modifications to polymeric films through additives, such as through the addition of dyes and/or metallic deposits to the coating layer.

[0024] The coating layer(s) also provide flexibility, since the material thickness, melt characteristics, subsequent hardness after imprinting, and other various properties of the coating layer(s) can be customized. This can be useful, for example, when imprinting nanometer/micrometer-scale patterns that require high clarity or low reflectance, which can be controlled by the composition and/or structure of the surface of the embossing tools, resulting in, for example, a high-gloss or matte texture. A wider spectrum of tooling may be utilized when imprinting into a coating layer having a lower T_g and the tooling used may be preserved as a result of the lower temperatures and pressures used during the embossing process, which may provide cost savings. The resulting T_g of the coating layers described herein may be determined using methods known in the field, such as thermal analysis techniques, and more specifically, for example, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermo mechanical analysis (TMA). These three techniques, DSC, DMA, and TMA make measurements of the material response while the sample is heated using a controlled temperature ramp profile, which is a built-in programmable feature in the control software of most commercially available instrumentation.

[0025] FIG. 1 illustrates a flow diagram of a general embossing technique in accordance with one or more embodiments. First, a coating layer having a lower T_g is applied to a substrate, i.e., a polymeric film base layer, in this example embodiment. The various layers added to the polymeric film base layer described herein may be very thin, especially in the context of nanometer/micrometer-scale surface imprinting, ranging from 1 nanometer to 500 micrometers in thickness; however, for other applications, the layer(s) may be significantly thicker. Layers in the thin-film range (typically 1 nanometer to several micrometers in thickness), such as optional metallic layers, may be applied using various thin-film deposition techniques known in the field, such as chemical deposition (e.g., plating) or physical deposition (e.g., sputtering). Thicker layers (typically ranging from 1-500 micrometers), such as the coating layer(s), may be applied to the polymeric film substrate using various roll-to-roll techniques known in the field, such as knife-over-roll coating, metering rod (Meyer bar) coating, or slot die (extrusion) coating. Roll- to-roll techniques may be used when the polymeric film substrate is a sheet of material; however, other application techniques may also be used.

[0026] The depth of the patterns and/or features imprinted into the coating layer(s) described herein may be in the range of 1-200 micrometers in the context of micrometer-scale surface imprinting. In some instances, the patterns and/or features may have depths in the following ranges: 1-20, 1-50, 1-100, 10-25, 10-50, 25-75, 30-100, 50-150, or 100-200 micrometers. In other instances, the depth of the patterns and/or features may be larger depending on the application or desired effects, such as 200 micrometers to 100 millimeters. The maximum obtainable depth of the patterns and/or features may be dependent on the thickness of the coating layer(s). For example, in a composite where one coating layer having a thickness of 100 micrometers is used, the maximum obtainable depth of the patterns and/or features embossed into that coating layer may be 100 micrometers (and may actually be smaller due to the compressive forces and heat applied to the coating layer during the embossing process). The maximum obtainable depths may be expressed or chosen as a percentage of the coating layer(s) thickness(es). The tooling used during the embossing process and/or the desired optical and/or decorative effects may affect the maximum and/or minimum obtainable depth of the patterns and/or features.

[0027] The minimum obtainable width (the dimension in the plane parallel to the coating layer) of the patterns and/or features imprinted into the coating layer(s) described herein may be in the range of 1-100 micrometers. In some instances, the patterns and/or features may have minimum widths in the following ranges: 1-20, 10-25, 10-50, 20-50, 20-80, 30-75, or 30-100 micrometers. In other instances, the minimum width of the patterns and/or features may be larger depending on the application or desired effects, such as 100 micrometers to 10 centimeters. The tooling used during the embossing process and/or the desired optical and/or decorative effects may affect the minimum obtainable width of the patterns and/or features.

[0028] The addition of the coating layer(s) may achieve an optical or decorative effect before being imprinted. For example, the refractive indices of the polymeric film and coating layer(s) can be selected to be transparent (matching refractive indices) or light diffusive/reflective (non- matching refractive indices). Optical and/or decorative effects may also be achieved through the addition of one or more dyes and/or metallic depositions, such as partial light blocking, known as tinting. One or more coating layers may be applied to one or both sides of the polymeric film. When applying a coating layer to both sides of the polymeric film, the coating layers on either side may vary in material, characteristics, and/or thickness, and thus allow for the sides to have different patterns imprinted into them.

[0029] The coated polymeric film can then be embossed to form the desired patterns into the coating layer. As previously described, and as is known in the field, embossing requires heat and/or pressure to form patterns onto substrates. Typically, the material being embossed will be heated to a temperature that is between its glass transition temperature (T_g) and its melting temperature (T_m). This temperature generally places the material into a malleable, molten, or rubber-like state. Embossing into a coating layer having a lower T_g relative to the polymeric film it is applied to may help prevent the base polymeric film from being stressed or altered. This can be particularly useful, for example, in embodiments that utilize rollers to form patterns onto a polymeric film, because the base polymeric film may remain unaffected if using temperatures in the embossing process that are lower than the T_g of the polymeric film substrate, thereby allowing the film to stay in its solid state as the composite goes through the rollers to emboss the coating layer.

[0030] The embossed polymeric film may then have additional layers added to it, such as an overlaminate or over-coat layer to freeze the features/patterns in place or to provide additional functionality (e.g., to achieve effects such as one-way visibility). In some instances, additional layers may include, for example, a metallic layer (e.g., sputtered or vacuum deposited), a release liner layer, an additional embossed coating layer, or a protective layer (e.g., a scratch-resistant layer). In some instances, additional layers may be added to provide an optical or decorative affect, such as to modify the refractive index or other properties of the final embossed composite. The additional layers may be applied, for example, using an adhesive or an inert solvent or by using one of the processes disclosed herein for applying the coating layer to the polymeric film substrate. The optional additional layers may contribute an optical or decorative effect to the final composite, or they may serve another purpose, such as to protect the final composite from external elements, weathering, or wear.

[0031] FIG. 2 illustrates various components of a low T_g coating layer in accordance with one or more embodiments. The coating layer may include one, two, three, or more components, such as, for example, various monomers, polymers, copolymers, or terpolymers. As shown in this embodiment, the two main components used to create the coating layer include at least one acrylic material combined with at least one fluoropolymer material. In this example embodiment, the acrylic(s) and fluoropolymer(s) are combined using a solvent to dissolve the two materials and create a solution of the coating layer. The solvents used may be polar or non- polar; however, most fluoropolymers exhibit greater solubility in polar solvents. Solvents may include, for example, various acetates, ethers, ketones, aldehydes, and aliphatic, aromatic, and substituted hydrocarbons. In some embodiments, the solvents may more specifically include acetone, methyl ethyl ketone (MEK), Methyl isobutyl ketone (MIBK), cyclohexanone, N- methyl-2-pyrrolidone (NMP), or dimethylacetamide (DMAC). Solvents may be combined to provide optimum solubility and ensure that the coating layer solution has the desired surface energy. The acrylic and fluoropolymer materials may be combined using other techniques, such as melting them together using a source of heat and a mixer.

[0032] The combination of acrylic and fluoropolymer materials provides numerous benefits for use in the coating layer in one or more embodiments. Looking at the materials individually, acrylics are polymers that are generally transparent, maintain a high optical clarity, and can be molded into a variety of different shapes, qualities that are favorable to both embossing and use in optical or decorative applications. Acrylics are colorfast and dyes can be easily added or applied to them. Acrylics have good adhesive qualities, which helps the coating layer adhere to the polymeric film substrate upon application. Acrylics are lightweight, but have high tensile strengths, making the materials shatterproof, and they are very durable, because of their weather- resistant properties.

[0033] Like acrylics, fluoropolymers, such as polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), fluorinated ethylene vinyl ether (FEVE), and ethylene tetrafluoroethylene (ETFE), are generally transparent, have high tensile strengths, and have good resistance to weatherability and wear. However, fluoropolymers have a relatively low T_g (e.g., near -40 °C) compared to both acrylics and conventional polymeric films. In some embodiments, fluoropolymers are combined with acrylics to produce a coating layer having the beneficial qualities of both fluoropolymers and acrylics, but also having a lower T_g than conventional polymeric films. Cost savings may be realized by using one or more coating layers to obtain desired optical or decorative effects. For example, a lower amount of energy may be used during the embossing process, since the coating layer has a lower T_g than conventional polymeric films, and thereby requires less heat to reach a malleable state for imprinting desired features/patterns.

[0034] In some instances, other materials may be substituted for the acrylic and/or fluoropolymer materials, as long as the resulting coating layer has a lower T_g than the polymeric film substrate, such as using poly(a-methylstyrene) (PaMS) or poly(methyl methacrylate) (PMMA) in place of the acrylic(s). In some embodiments, the coating layer can be made by combining monomers having a low T_g with monomers having a high T_g through the process of, for example, radiation curing. Other materials may be added to the coating layer solution to change the properties of the solution or to suit the desired optical or decorative effect. For example, dyes or metallic particles may be added to change the appearance and/or optical properties of the coating layer, and thus the appearance and/or optical properties of the final composite. Other additives, such as variations of benzophenone (e.g., 2-methylbenzophenone, 4- methylbenzophenone, etc.), may be used to stabilize the material characteristics or optical properties of the final coating layer.

[0035] In some embodiments having at least one coating layer comprised of two or more components, the ratio of the components can be used to select a desired T_g. For example, in this example embodiment, when combining acrylics that have high T_gs with fluoropolymers that have low T_gs, the resultant T_g of the coating layer may be in the range of 5 to 60 °C. If, for example, a coating layer with a low T_g is desired, then a high ratio of the fluoropolymer material to the acrylic material may be used to produce, for example, a coating layer having a T_g in the 5 to 30 °C. If, for example, a coating layer with a high T_g is desired, then a high ratio of the acrylic material to the fluoropolymer material may be used to produce, for example, a coating layer having a T_g in the 31 to 60 °C range. In some instances, the coating layer may have a T_g in one of the following ranges: 5-20, 10-50, 15-30, 30-60, 25-50, 5-15, or 10-25 °C. In other instances, the coating layer may have a lower or higher T_g for various applications, such below 5 °C or greater than 60 °C. In one or more embodiments, the coating layer may be made from the combination of a high T_g material with a low T_g material in the following weight ratios (either high:low or low:high) - 20: 1, 10: 1, 5: 1, 5:2, 4: 1, 3: 1, 3:2, 2: 1, 1 : 1. In some instances, the coating layer may be comprised of various percentages of different components, such as a coating layer comprised of 25% of material A (a high T_g material), 35% of material B (a high T_g material), and 40% of material C (a low T_g material). [0036] The coating layer T_g may be expressed relative to the T_g of the polymeric film substrate T_g or, in some instances, it may be desired to know the minimum difference between the polymeric film substrate T_g and the coating layer T_g. For example, in manufacturing environments that can only control temperature accuracy within 10 °C, a minimum difference of 20 °C between the T_g of the polymeric film substrate and the coating layer may be required to prevent stress to the polymeric film substrate while maintaining a temperature that allows the coating layer to be embossed. In some instances, the minimum difference between the polymeric film substrate T_g and the coating layer T_g may be approximately 10, 15, 30, 40, 50, 75, or 100+ °C. The T_g of the coating layer may be expressed or chosen as a percentage of the polymeric film substrate's T_g. Therefore, the coating layer T_g, relative to the polymeric film substrate T_g, may be in one of the following ranges: 1-10, 5-25, 10-25, 10-50, 25-50, 25-75, 50- 75, 50-90, or 75-95 %. The resulting T_g of the coating layers described herein may be determined and/or approximated based on the ratios and T_gs of the coating layer components. For example, if a coating layer were primarily made from equal parts of two components, then the resulting sample coating layer may have a T_g approximately half between the T_gs of the two components. More specifically, in an example embodiment having a coating layer made from equal parts of an acrylic having a T_g of 70 °C and a fluoropolymer having a T_g of -30 °C, the resulting coating layer T_g may be approximately 20 °C.

[0037] A sample lower T_g coating layer solution was made by combining 22.7 kg (50 lbs) of acrylic resin (DOW Paraloid A-101) with 14.5 kg (32 lbs) of fluoropolymer resin (Arkema Kynar PVDF). These materials were dissolved in a solvent made by combining 25.9 kg (57 lbs) of MEK with 31.3 kg (69 lbs) of cyclohexanone. In addition, 1.6 kg (3.5 lbs) of 4- methylbenzophenone was added to stabilize the coating layer solution. The sample coating layer had a resulting T_g in the range of 45 °C to 50 °C. The coating layer was then applied at a thickness of approximately 40 micrometers to a PET film substrate that has a higher T_g relative to the coating layer. The coating layer facilitated embossing the desired optical patterns onto the composite at lower temperatures and pressures.

[0038] FIG. 3A illustrates an exploded view of the layers of a coated polymeric film composite prior to being embossed in accordance with an embodiment. All of the layers in this composite 1 have been shown in an exploded manner for ease of reference. The base substrate layer 2 is shown already coated by the coating layer 3; however, the coating layer 3 is shown prior to being embossed. In this embodiment, the substrate layer 2 is a polymeric film and is coated with a coating layer 3 having a lower T_g than the polymeric film layer 2. The polymeric film layer 2 may have a thickness ranging from 1-500 micrometers when used for imprinting on the nanometer/micrometer scale and may be made from a polymeric film, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), or poly(methyl methacrylate) (PMMA). In some instances, the polymeric film substrate layer 2 may have one of the following thickness ranges: 10-400, 20-300, 25-200, 50-300, 1-100, or 50-100 micrometers. In other instances, the polymeric film layer 2 may be thicker for various applications, such as 500 micrometers to 1 centimeter.

[0039] In one or more embodiments, the low T_g coating layer 3 may have a thickness ranging from 1-200 micrometers and can be made from at least a combination of two components or materials, such as acrylic and fluoropolymer materials, as disclosed herein. In some instances, the coating layer 3 may have one of the following thickness ranges: 50-150, 30-100, 1-50, 20- 125, 10-75, or 1-100 micrometers. In other instances, the coating layer 3 may be thicker for various applications, such as 200 micrometers to 100 millimeters. The thickness of the coating layer 3 may be expressed or chosen relative to the thickness of the polymeric film substrate layer 2. Therefore, the coating layer thickness, relative to the polymeric film substrate thickness, may be in one of the following percentage ranges: 1-10, 5-25, 10-25, 10-50, 25-50, 25-75, 50-75, 50- 90, or 75-95 %. The coated composite thickness could also be expressed or chosen as a ratio of the polymeric film substrate layer thickness to the coating layer thickness, including, for example, the following ratios - 1 : 1, 2: 1, 3:1, 4:1, 5: 1, 10: 1, 15: 1, 20: 1, 50:1, 3:2, 4:3, 5:2, or 5:3. This example composite includes additional layers that may be applied after the coating layer 3 has been embossed (although one or more of the layers may be applied prior to embossing): a metallic layer 4; an overlaminate or over-coat layer 6 applied using an adhesive 5; a protective layer 7; and a release liner layer 9 applied over an adhesive layer 5.

[0040] The metallic layer 4 may be added before or after embossing the coating layer. The metals in this layer may include, for example, gold, silver, aluminum, copper, or tin. The metallic layer may be very thin and can be applied using various processes known in the field, such as sputtering metallic particles (typically in the 200-600 nanometer range) onto the coating layer, making a layer having a thickness, for example, in the nanometer to several micrometer range. The metallic layer may be added to provide various optical effects, such as two-way mirroring. The metallic layer may provide decorative effects, such as to give the final composite a shiny or metallic appearance. In some instances, the metal may be included in the coating layer 3 prior to embossing. This may be achieved by, for example, including metallic particles (typically in the 10-200 nanometer range) in the low T_g coating layer solution, as described herein. The metallic layer 4 may have one of the following thickness ranges: 0.5-2, 1-5, 1-10, 2- 20, 5-20, or 1-100 micrometers.

[0041] The overlaminate or over-coat layer 6 may be applied to the coating layer 3 using an adhesive 5 to freeze the embossed pattern in place. Freezing the pattern embossed in the coating layer may mean to hold the pattern in place and/or to prevent it from being damaged. The overlaminate layer may protect the embossed polymeric film from, for example, scratches, dirt, fingerprints, weather, or light (such as ultraviolet light). The overlaminate may be a transparent sheet in the 1-500 micrometer thickness range and may be made from a polymeric material, such as polyethylene terephthalate (PET) or polypropylene. In some instances, the overlaminate layer 6 may have one of the following thickness ranges: 10-400, 20-300, 25-200, 50-300, 1-100, or 50- 100 micrometers. The overlaminate may have an optical or decorative effect on the final composite, especially if the overlaminate is dyed or colored in some manner. In some instances, the overlaminate may be applied using other techniques, such as using heat, pressure, ultrasound, or solvents to bond the overlaminate layer to other layers.

[0042] The protective layer 7 may be applied as the last or outer layer to help protect the final composite from external elements. The protective layer may be very thin and can be applied in a coating-fashion similar to the way that the coating layer is applied to the polymeric film substrate. In some instances, the protective layer may be a thin sheet of material that can be applied using an adhesive or some other bonding method. The protective layer may provide additional desired qualities depending on the chosen material, such as scratch-resistant or water- resistant qualities. The protective layer 7 may have one of the following thickness ranges: 0.5-2, 1-5, 1-10, 2-20, 1-100, or 1-500 micrometers.

[0043] The use of an adhesive layer 8 and release liner layer 9 can be used when the final composite is constructed to apply or stick to another surface, such as a window or screen. The adhesive layer 8 may be applied to the underside of the polymeric film 2, i.e., the side opposite the coating layer 3 in this example composite. The release liner layer 9 will typically be applied on the adhesive layer 8. The release liner layer 9 may be coated on one or both sides with a release agent to provide a release effect against the adhesive layer 8 to allow for easy removal of the release liner 9. In application, once the release liner 9 is removed, the adhesive layer 8 is exposed for applying the final composite to another surface or object (such as a window or screen). The adhesive layer 8 may have one of the following thickness ranges: 0.5-2, 1-5, 1-10, 2-20, 5-20, or 1-100 micrometers.

[0044] FIG. 3B illustrates the coated polymeric film composite in FIG. 3A after the coating layer has been embossed and the additional layers have been applied. The reference numbers in this final embossed composite 11 correspond to the reference numbers in the exploded view composite 1 of FIG. 3A. Accordingly, the base substrate layer 12 corresponds to the base substrate layer 2, and so forth. The coating layer 3 may be first embossed as disclosed herein to produce the resulting pattern shown in the embossed coating layer 13. The metallic layer 4 may then be applied to the embossed coating layer 13 to metallize 14 that layer. The overlaminate layer 6 may then be glued onto the metallized coating layer using the clear adhesive 5, resulting in an overlaminate 16 that helps to freeze the pattern in the embossed coating layer 13. The protective layer 7 may be applied to the overlaminate 16 as a thin protective coating 17. The adhesive 8 may be applied to the underside of the polymeric film substrate 12 to create an adhesive layer 18 that allows the final composite 11 to be conveniently applied to another object or surface. The release liner layer 9, 19 may be applied to adhesive layer 18 to protect the adhesive and allow for a convenient application of the final composite 11 onto other objects or surfaces.

[0045] FIG. 4A illustrates a polymeric film composite having two coating layers prior to being embossed in accordance with an embodiment. This composite 21 shows a polymeric film substrate 22 that is coated by a first coating layer 23 and a second coating layer 24 on either side of the polymeric film substrate 22. The coating layers 23, 24 can be either the same material or different materials; however, both coating layers 23, 24 may have lower T_gs than the polymeric film substrate 22. FIG. 4B illustrates the coated polymeric film composite in FIG. 4A after the coating layers have been embossed. The reference numbers in the final embossed composite 31 of this figure correspond to the reference numbers in the non-embossed composite 21 of FIG. 4B. Accordingly, the polymeric film substrate 22 corresponds to the polymeric film substrate 32, and the coating layers 23, 24 correspond to the embossed coating layers 33, 34.

[0046] Coating both sides of the polymeric film substrate 22 may provide additional flexibility during the embossing process. For example, if the coating layers 23, 24 are made from different materials having different T_gs, then the coating layers 23, 24 may be embossed one at a time to produce distinct patterns in each coating layer 23, 24. The first coating layer 23 material may have a first glass transition temperature T_gl and the second coating layer 24 material may have a second glass transition temperature T_g2 , where T_gl is greater than T_g2. The first coating layer 23 may be applied to the polymeric film substrate 22 and then embossed during a first embossing process prior to applying the second coating layer 24. The first embossing process may be performed at a temperature higher than T_gl in order to imprint into the first coating layer 23. The second coating layer 24 may then be applied to the other side of the polymeric film substrate 22 and this second coating layer 24 may be embossed during a second embossing process. The second embossing process may be performed at a temperature that is in between T_g2 and T_gl in order to imprint into the second coating layer 24 while keeping the embossed first coating layer 33 in an unaffected solid state.

[0047] FIG. 5 illustrates an embossed polymeric film composite having multiple coating layers in accordance with an embodiment. The composite 41 shows a polymeric film substrate 42 having a first coating layer 43 that has been embossed to produce the pattern shown in the first coating layer 43. A second coating layer 44 may be applied on the first coating layer 43 to produce an additional optical or decorative effect. A third coating layer 45 may be applied on the second coating layer 44 to produce an additional optical or decorative effect. A fourth coating layer 46 may be applied on the third coating layer to produce an additional optical or decorative effect. Each successive layer may have a T_g lower than the previous layer(s) to facilitate, for example, bonding the successive layer to the previous layer(s) and/or embossing into the successive layer without affecting the previous layer(s). One or more of the additional coating layers may optically affect the entire composite upon application by, for example, changing the refractive index of the composite or having a light blocking dye in that layer (e.g., a dye that blocks ultraviolet light). One or more of the additional coating layers may optically affect the composite after being imprinted. One or more of the additional coating layers may protect the composite by adding resistance to, for example, weather, wear, scratches, fingerprints, and/or external elements.

[0048] FIG. 6 is a photomicrograph of a tool having a micro-optic pattern used to emboss a polymeric film composite in accordance with an embodiment. More specifically, the photomicrograph depicts a raised surface pattern on steel plated over with chrome. As can be seen, the raised surface pattern has a length of 30.3 micrometers. FIG. 7 is a photomicrograph of an embossed polymeric film composite depicting a micro-optic pattern in accordance with an embodiment. The polymeric film composite consists of a polymeric film substrate with a coating, where the coating has a lower T_g than the substrate. The micro-optic pattern shown in FIG. 7 was imprinted in the low T_g coating using the tool from FIG. 6. The photomicrographs shown in FIGS. 6 and 7 were taken with a 5 megapixel (MP) Motic microscope imaging system using a Nikon Eclipse 55i clinical microscope at 20x.

[0049] While several embodiments have been described and illustrated herein, those of ordinary skill in the art readily will envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art readily will appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Therefore, it is to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and/or methods, if such features, systems, articles, materials, and/or methods are not mutually inconsistent, is included within.

[0050] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one." The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified, unless clearly indicated to the contrary.

[0051] The term "layer" as used herein in the specification and in the claims, in the context of applying or coating, should be understood to include both partial and complete applications and/or coatings. The term "composite" as used herein in the specification and claims, should be understood to include two or more layers (e.g., a polymeric film substrate layer, a coating layer, an overlaminate layer, etc.) combined in some manner (e.g., coated, applied with an adhesive, applied without an adhesive, etc.), such as a polymeric film substrate having a coating layer. The term "pattern" as used herein in the specification and claims, should be understood to include individual features, such as words, symbols, parallel or concentric lines, or any other distinctive design.

[0052] The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.

[0053] What is claimed is:

Claims

1. A method of embossing a coated polymeric film composite, the method comprising: applying a first coating layer to a first side of a polymeric film substrate, wherein the first coating layer has a lower glass transition temperature (T_g) than the polymeric film substrate; and

embossing at least one pattern in the first coating layer.

2. The method of claim 1, further comprising combining at least one acrylic and at least one fluoropolymer to make the first coating layer.

3. The method of claim 2, wherein the at least one acrylic and at least one fluoropolymer are combined using a solvent.

4. The method of claim 3, wherein the solvent includes at least one of acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, N-methyl-2-pyrrolidone (NMP), and dimethylacetamide (DM AC).

5. The method of any of claims 1-4, further comprising:

applying a second coating layer to the embossed first coating layer, wherein the second coating layer has a lower T_g than the first coating layer; and

embossing at least one pattern in the second coating layer.

6. The method of any of claims 1-4, further comprising:

applying a second coating layer to a second side of the polymeric film substrate, wherein the second coating layer has a lower T_g than the polymeric film substrate; and embossing at least one pattern in the second coating layer.

7. The method of any of claims 1-4, further comprising:

applying a metallic layer to the embossed first coating layer;

applying an overlaminate layer to the metallic layer; and

applying a protective layer to the overlaminate layer.

8. A coated polymeric film composite, comprising:

a polymeric film substrate layer; and

a first coating layer applied to the polymeric film substrate, the first coating layer having a lower glass transition temperature (T_g) than the polymeric film substrate layer, wherein at least one pattern is imprinted in the first coating layer.

9. The composite of claim 8, wherein the imprinted first coating layer provides an optical and/or decorative effect to the composite.

10. The composite of claim 8, wherein the first coating layer is made from a solution of at least one acrylic, at least one fluoropolymer, and a solvent.

11. The composite of claim 8, wherein the first coating layer is further comprised of at least one dye and/or at least one metallic deposition.

12. The composite of claim 8, wherein the T_g of the first coating layer is in the range of 5 to 60 °C.

13. The composite of claim 8, wherein the difference between the polymeric film substrate layer T_g and the first coating layer T_g is at least 20 °C.

14. The composite of claim 8, wherein the first coating layer has a thickness in the range of 1 to 200 micrometers.

15. The composite of claim 8, wherein the at least one pattern imprinted in the first coating layer redirects light passing through the composite.

16. The composite of claim 8, wherein the first coating layer adheres to the polymeric film substrate layer without the assistance of an additional adhesive.

17. The composite of any of claims 8-16, further comprising one or more additional coating layers applied to the composite, wherein the one or more additional coating layers are imprinted with at least one pattern.

18 The composite of any of claims 8-16, further comprising one or more additional layers applied to the composite, wherein the one or more additional layers includes at least one of an overlaminate layer, protective layer, scratch-resistant layer, adhesive layer, metallic layer, and/or dyed layer.

19. A coated polymeric film composite, comprising:

a polymeric film substrate layer;

a first coating layer comprised of at least one acrylic and at least one fluoropolymer, wherein the first coating layer is applied to the polymeric film substrate layer and the first coating layer has a lower glass transition temperature (T_g) than the polymeric film substrate layer; and

at least one pattern imprinted in the first coating layer to provide an optical and/or decorative effect to the composite.

20. The composite of claim 19, wherein the at least one pattern imprinted in the first coating layer is on a micrometer scale.