Films Comprising Hybrid Solvent Barrier and Primer Layers - Patent application

Abstract

Conformable, stretchable, and printable films are described. In particular, films are described that include a film substrate, a pressure-sensitive adhesive, and a hybrid solvent barrier / primer layer that includes a blend of two immiscible copolyamides. Such hybrid solvent barrier and primer layers can be effective as both solvent barrier and primer layers.

Description

[Background technology]

[0001] Certain films are used to display graphics and other visual information when adhered to a surface. These films may be made in part by printing inks onto the ink-receptive surface of such films. Because the inks are generally solvent-based, some of these solvents may permeate through the thickness of the film into the adhesive layer, causing undesirable tack and poor peelability. Certain pressure-sensitive adhesives may have poor adhesion to the film substrate, making the film susceptible to delamination without an intermediate layer having adequate adhesion to each of the adhesive and substrate. Summary of the Invention

[0002] In one aspect, the present disclosure relates to a conformable, stretchable, printable film. The film includes a film substrate having a first major surface for receiving ink, a pressure sensitive adhesive, and a hybrid solvent barrier / primer layer. The hybrid solvent barrier / primer layer is disposed between and bonded to both the film substrate and the pressure sensitive adhesive, and is disposed on the side opposite the first major surface of the film substrate. The hybrid solvent barrier / primer layer includes two copolyamides that are not miscible, the hybrid solvent barrier / primer layer including one copolyamide that is a continuous phase and one copolyamide that is a discontinuous phase.

[0003] In another aspect, the present disclosure relates to a method of providing a conformable, stretchable ink receptive film having a hybrid solvent barrier / primer layer, the method including providing a film substrate, coating a blend of two immiscible copolyamides on a major surface of the film substrate to form a hybrid solvent barrier / primer layer in which one copolyamide is the continuous phase and one copolyamide is the discontinuous phase, and applying a pressure sensitive adhesive layer on the hybrid solvent barrier / primer layer.

[0004] In yet another aspect, the present disclosure relates to a conformable, stretchable, printable film. The film includes a film substrate having a first major surface for receiving ink, a pressure sensitive adhesive, and a hybrid solvent barrier / primer laminate. The hybrid solvent barrier / primer laminate is disposed between and bonded to both the film substrate and the pressure sensitive adhesive, and is disposed on the opposite side of the film substrate from the first major surface. The hybrid solvent barrier / primer laminate includes two layers, each of the layers in the hybrid solvent barrier / primer layer includes two copolyamides that are not miscible. Each of the layers in the hybrid solvent barrier / primer layer includes a different blend of the same two copolyamides. [Brief description of the drawings]

[0005] [Figure 1] 1 is a side cross-sectional schematic diagram of an embodiment of a film including a hybrid solvent barrier and primer layer. FIG. [Diagram 2] FIG. 2 is a side cross-sectional schematic diagram of another embodiment of a film comprising a two-layer hybrid solvent barrier and primer laminate. [Diagram 3] FIG. 2 is a side cross-sectional schematic view of another embodiment of a film comprising a three-layer hybrid solvent barrier and primer laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Graphic films, including large format graphics for use in displaying information on vehicles, walls, and signs, are typically provided as adhesive films for easy temporary, semi-permanent, or permanent (whether peelable or not) positioning on a substrate. Such films may be non-pigmented (transparent), white, or any other suitable color. In many cases, the films may be designed to be printable (i.e., may be inherently ink-receptive or may include an ink-receptive coating) so that an image or other information may be transferred onto the film. For example, a brand owner may want to provide advertising, logos, or other information on the film to be adhered to a truck or van.

[0007] Inks are usually applied by printing. Large format printing is widely available using solvent-based inks. Water-based latex inks exist but are not commonly used. Inks are typically applied only to the top surface of such films, and the solvents used in the most common ink systems permeate through the layer and eventually migrate to the adhesive layer. Solvent migration to the adhesive layer can alter the otherwise carefully tuned properties of the adhesive layer, making application and peelability difficult. In some applications, contaminant migration in other ways (i.e., from the adhesive to the ink-receiving substrate) can also be an issue.

[0008] To address this issue, certain films feature multi-layer systems. One of the layers is designed to act as a solvent barrier, and one or more layers are used to allow the solvent barrier layer to adhere to the remaining layers of the film, called primer or prime layers. Depending on the substrate and adhesive system used, the film may use a primer layer on both sides of the solvent barrier layer.

[0009] Combining the properties of a primer layer and a solvent barrier layer is not as simple as blending two polymers with these properties. Co-processability (e.g., the ability to be co-extruded or dissolved in a common solvent) may be necessary for commercial-scale manufacturing. Furthermore, barrier properties are typically only effective if the solvent cannot easily penetrate any point in the layer. If the blend allows the path of the solvent to migrate through the layer, it may be ineffective as a barrier. Furthermore, the blend percentages that may be required to create an effective solvent barrier may render it ineffective as a primer layer. Finally, not all blends that can be both effective solvent barriers and primer layers are suitable for stretchable conformable film systems and may crack, delaminate, or otherwise be brittle when handled and applied.

[0010] Surprisingly, the use of two copolyamides that are not miscible in a hybrid solvent barrier / primer layer, one copolyamide being the continuous phase and one copolyamide being the discontinuous phase, can provide both effective barrier performance and effective primer performance. In some embodiments, one of the copolyamides includes tertiary amide functionality and one of the copolyamides does not have tertiary amide functionality. In some embodiments, the copolyamide with tertiary amide functionality is the discontinuous phase copolyamide. In these embodiments, the copolyamide without tertiary amide functionality is the continuous phase. In addition to the respective embodiments, the following aspects are noted. (Appendix 1) A conformable, stretchable, printable film comprising: a film substrate having a first major surface for receiving ink; A pressure sensitive adhesive; a hybrid solvent barrier / primer layer disposed between the film substrate and the pressure sensitive adhesive and disposed on a side of the film substrate opposite the first major surface; the hybrid solvent barrier / primer layer comprises two immiscible copolyamides; A film, wherein the hybrid solvent barrier / primer layer comprises one copolyamide that is a continuous phase and one copolyamide that is a discontinuous phase. (Appendix 2) 2. The film of claim 1, wherein the two copolyamides include a copolyamide having tertiary amide functionality and a copolyamide without tertiary amide functionality. (Appendix 3) 3. The film of claim 2, wherein the copolyamide having tertiary amide functionality is 50% or less by weight of the two copolyamides. (Appendix 4) 3. The film of claim 2, wherein the copolyamide having tertiary amide functionality is 40% or less by weight of the two copolyamides. (Appendix 5) 2. The film of claim 1, wherein the hybrid solvent barrier / primer layer is 5 micrometers or thinner. (Appendix 6) 2. The film of claim 1, wherein the hybrid solvent barrier / primer is 1 micrometer or thinner. (Appendix 7) 2. The film of claim 1, wherein the two copolyamides of the hybrid solvent barrier / primer layer are soluble in a mixture of n-propanol and water. (Appendix 8) 2. The film of claim 1, wherein the two copolyamides of the hybrid solvent barrier / primer layer are soluble in polar solvents. (Appendix 9) 2. The film of claim 1, wherein the two copolyamides of the hybrid solvent barrier / primer layer are coextrudable. (Appendix 10) 2. The film of claim 1, wherein the hybrid solvent barrier / primer layer comprises a pigment. (Appendix 11) 2. The film of claim 1, wherein the film substrate comprises polyvinyl chloride. (Appendix 12) 2. The film of claim 1, wherein the film substrate comprises polyurethane. (Appendix 13) 2. The film of claim 1, wherein the hybrid solvent barrier / primer layer is bonded to both the film substrate and the pressure-sensitive adhesive layer. (Appendix 14) 2. The film of claim 1, further comprising a layer disposed between and bonded to both the hybrid solvent barrier / primer layer and the film substrate. (Appendix 15) 15. The film of claim 14, wherein the hybrid solvent barrier / primer layer bonds to the layer and to the pressure sensitive adhesive layer. (Appendix 16) 15. The film of claim 14, wherein the layer comprises an aminoethylated acrylic polymer. (Appendix 17) 15. The film of claim 14, wherein the layer comprises a crosslinked acrylic acrylate-amine copolymer. (Appendix 18) 15. The film of claim 14, wherein the layer comprises a pigment. (Appendix 19) 1. A method for providing a conformable, stretchable, printable film having a hybrid solvent barrier / primer layer, comprising: Providing a film substrate; coating a blend of two immiscible copolyamides onto a major surface of said film substrate to form a hybrid solvent barrier / primer layer in which one copolyamide is a continuous phase and one copolyamide is a discontinuous phase; applying a pressure sensitive adhesive onto said hybrid solvent barrier / primer layer. (Appendix 20) 20. The method of claim 19, wherein the blend of two copolyamides is solvent-based and coating means solvent coating. (Appendix 21) 20. The method of claim 19, wherein the blend of two copolyamides is hot melt processable and coating means extrusion coating. (Appendix 22) 20. The method of claim 19, wherein the film substrate is a primed film substrate. (Appendix 23) A conformable, stretchable, printable film comprising: a film substrate having a first major surface for receiving ink; A pressure sensitive adhesive; a hybrid solvent barrier / primer laminate disposed between and bonded to both the film substrate and the pressure sensitive adhesive, the hybrid solvent barrier / primer laminate being disposed on a side of the film substrate opposite the first major surface; The hybrid solvent barrier / primer laminate comprises two layers: each of the layers of the hybrid solvent barrier / primer laminate comprises two immiscible copolyamides; A film, wherein each of said layers of said hybrid solvent barrier / primer laminate comprises a different blend of said two same copolyamides. (Appendix 24) 24. The film of claim 23, wherein the film substrate is a primed film substrate. (Appendix 25) 24. The film of claim 23, wherein each of the layers comprises a copolyamide having tertiary amide functionality and a copolyamide without tertiary amide functionality. (Appendix 26) 24. The film of claim 23, wherein the hybrid solvent barrier / primer laminate comprises one layer comprising greater than 50% by weight of a copolyamide having tertiary amide functionality, and the hybrid solvent barrier / primer laminate comprises one layer comprising 50% by weight or less of a copolyamide having tertiary amide functionality. (Appendix 27) 24. The film of claim 23, wherein the hybrid solvent barrier / primer laminate comprises a third layer, the third layer comprising a blend of the two same copolyamides that is different from at least one of the other two layers. (Appendix 28) 26. The film of claim 25, wherein two layers of the hybrid solvent barrier / primer laminate comprise greater than 50% by weight of a copolyamide having tertiary amide functionality and one layer of the hybrid solvent barrier / primer laminate comprises 50% or less by weight of a copolyamide having tertiary amide functionality.

[0011] 1 is a schematic cross-sectional side view of an embodiment of a film including a hybrid solvent barrier and primer layer. The film 100 includes a film substrate 110, a hybrid solvent barrier and primer layer 120, an adhesive layer 130, and an optional liner 140.

[0012] The substrate 110 may be any suitable substrate and may be any desired shape or size. The substrate 110 may be formed as a cast, calendared, or extruded film substrate. In some embodiments, the substrate 110 may be or include polyvinyl chloride (PVC). PVC is commonly used for graphics films that are exposed to the elements because of its good weatherability and outdoor durability. In some embodiments, the substrate 110 may be or include other polymers or polymer blends, such as polyurethanes (including thermoplastic polyurethanes), cellulose acetate butyrate, polyamides, polyolefins, polystyrenes, polycarbonates, polyacrylates, polyvinyl alcohols, polyvinyl butyrals, and fluoropolymers. The substrate 110 may be of any suitable thickness, which may in fact depend on the method by which it is manufactured. For example, the substrate may have a thickness of 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 125 μm, 150 μm, 175 μm, or 200 μm, or a range between any two of the previously listed values. The substrate 110 may include a pigment or other colorant. In some embodiments, the substrate 110 may include carbon black or titanium dioxide (white), although any pigment system may be selected for the desired application. In some embodiments, the substrate 110 may be a primed layer or may include a primer layer or other treatment to increase interlayer adhesion.

[0013] The hybrid solvent barrier / primer layer 120 may be formed from any suitable material and may be of any suitable thickness. In some embodiments, the hybrid solvent barrier / primer layer may be less than 10 μm, less than 8 μm, less than 6 μm, less than 4 μm, less than 3 μm, less than 2 μm, less than 1 μm, or even less than 0.5 μm. In some embodiments, the thinness of the hybrid solvent barrier / primer layer is limited in thickness only by the minimum thickness required to provide the desired barrier performance. In some embodiments, if the hybrid solvent barrier / primer layer is extruded, there may be a higher practical thickness due to the need to maintain the integrity of the web.

[0014] In some embodiments, the hybrid solvent barrier / primer layer 120 comprises a blend of two copolyamides. In some embodiments, the hybrid solvent barrier / primer layer 120 comprises one copolyamide with secondary amide functionality. In some embodiments, the hybrid solvent barrier / primer layer 120 comprises one copolyamide with tertiary amide functionality and one copolyamide without tertiary amide functionality. In some embodiments, the hybrid solvent barrier / primer layer 120 comprises 50% or less by weight of a copolyamide with tertiary amide functionality between the two copolyamides. In some embodiments, the hybrid solvent barrier / primer layer 120 comprises 40% or less by weight of a copolyamide with tertiary amide functionality between the two copolyamides. In some embodiments, the two copolyamides are soluble in common solvents. In some embodiments, the two copolyamides are soluble in a mixture of n-propanol and water. In some embodiments, the two copolyamides are co-extrudable.

[0015] Suitable copolyamides without tertiary amide functionality include ELVAMIDE 8063 (available from DuPont, Wilmington, Del.) and ULTRAMID 1C (available from BASF, Wyandotte, Mich.) Such copolyamides have low binding capacity but exhibit excellent solvent barrier performance.

[0016] Tertiary amide functional groups can enable effective bonding to pressure sensitive adhesives and polyvinyl chloride substrates. For example, copolyamides formed at least in part from monomers such as piperazine or dipiperazine show good adhesion to PVC substrates. Suitable copolyamides with tertiary amide functional groups include PLATAMID M1276 and PLATAMID HX2592T (available from Arkema NA; King of Prussia, Pa.). These copolyamides exhibit good bonding while providing little solvent barrier performance.

[0017] In some embodiments, the copolyamides are phase separated. In some embodiments, one copolyamide forms a continuous phase and one copolyamide forms a discrete or discontinuous phase. In such phase separated systems, despite including a polyamide that does not effectively prevent solvent migration, the hybrid solvent barrier / primer layer is still effective, even at low thicknesses, by having a copolyamide that exhibits good barrier performance that forms a continuous phase.

[0018] In some embodiments, the hybrid solvent barrier and primer layer is pigmented or includes a colorant. In some embodiments, the hybrid solvent barrier and primer layer may include carbon black. Pigmenting the hybrid solvent barrier and primer layer can aid in the perceived opacity of the final printed film.

[0019] The adhesive layer 130 may be made from or include a variety of adhesives, including pressure sensitive adhesives. Suitable adhesives may be selected by one skilled in the art and are often selected based on the type of substrate to which they will be adhered. Classes of pressure sensitive adhesives include acrylic, tackified rubber, tackified synthetic rubber, ethylene vinyl acetate, and silicone. Suitable acrylic adhesives are disclosed, for example, in U.S. Patent Nos. 3,239,478, 3,935,338, 4,952,650, 4,181,752, and 5,169,727.

[0020] A particular class of pressure-sensitive adhesives that may be useful for this particular application is the reaction product of at least one alkyl acrylate and at least one reinforcing comonomer. Suitable alkyl acrylates are those that have a homopolymer glass transition temperature of less than about -10°C, such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, octadecyl acrylate, etc. Suitable reinforcing monomers are those that have a homopolymer glass transition temperature of about -10°C, such as acrylic acid, methylidene succinic acid, isobornyl acrylate, N,N-dimethylacrylamide, N-vinyl caprolactam, N-vinyl pyrrolidone, etc.

[0021] The thickness of the adhesive layer 130 can be selected for a particular application based on several factors, including, for example, the composition of the adhesive, whether the adhesive includes a microstructured surface, the type of substrate, and the thickness of the film. One of ordinary skill in the art can adjust the thickness to address the factors of a particular application based on the disclosure herein. The adhesive layer 130 can be coated onto a liner and applied to the remainder of the film 100, or can be coated directly onto or coextruded with the remainder of the film 100.

[0022] The liner 140 is optional in structure, typically a paper or polymer liner with a coating for easy release from the adhesive layer. In some cases, the liner 140 may have a very uniform, smooth or glossy surface. In other instances, the liner may have a surface texture created by methods such as embossing or printing. In some embodiments, the liner includes a structured pattern, such as channels, ridges, or grooves. Such a structured pattern can impart an inverse structure onto the adhesive layer. This pattern can help apply the adhesive to the surface and provide easy air release, for example, during initial installation.

[0023] 2 is a schematic cross-sectional side view of another embodiment of a two-layer hybrid solvent barrier and primer film. The film 200 includes a film substrate 210, a first hybrid solvent barrier and primer layer 222, a second hybrid solvent barrier and primer layer 224, an adhesive layer 230, and an optional liner 240.

[0024] Film 200 is similar to film 100 of FIG. 1, except that the hybrid solvent barrier / primer layer is a two-layer laminate instead of a single layer. First hybrid solvent barrier and primer layer 222 and second hybrid solvent barrier and primer layer 224 each comprise a blend of two copolyamides. In some embodiments, the first and second hybrid solvent and primer layers are each different blends of the same two copolyamides. In some embodiments, the blend of the two copolyamides may phase separate. Due to phase separation, different blends of the same two copolyamides may have different performance. One blend may function as an effective barrier layer but have relatively low bonding capacity, while a slightly different blend may have moderate barrier performance but excellent bonding. Depending on the application and other layers in the film, these layers may be provided in any order. Having the same two copolyamides to achieve different effects may allow for a simplified or more adaptable manufacturing process. The proportions of the blends can be tweaked and adjusted to achieve the desired properties without the need for different components. In some embodiments, one layer comprises greater than 50% by weight copolyamide with tertiary amide functionality and one layer comprises 50% by weight or less copolyamide with tertiary functionality.

[0025] In some embodiments, the first hybrid solvent barrier and primer layer 222 may have negligible barrier performance and function primarily as a primer layer to promote interlayer adhesion between the substrate 210 and the second hybrid solvent barrier and primer layer 224. Such a layer would be disposed between and bonded to both the substrate 210 and the second hybrid solvent barrier and primer layer 224. In such embodiments, such a layer may be or include an aminoethylated acrylic polymer or a crosslinked acrylic acrylate-amine copolymer. Examples of suitable aminoethylated acrylic polymers include POLYMENT (available from Nippon Shokubai, Osaka, Japan). As with the layers described herein, such layers may include pigments or other colorants, including titanium dioxide (white) or carbon black.

[0026] 3 is a schematic cross-sectional side view of another embodiment of a film comprising a three-layer hybrid solvent barrier and primer laminate. Film 300 includes a film substrate 310, a first hybrid solvent barrier and primer layer 322, a second hybrid solvent barrier and primer layer 324, a third hybrid solvent barrier and primer layer 326, an adhesive layer 330, and an optional liner 340.

[0027] Film 300 of FIG. 3 is similar to film 200 of FIG. 2 and film 100 of FIG. 1, except that the hybrid solvent barrier / primer layer laminate is three layers instead of two layers, or a single layer. Like film 200 of FIG. 2, the hybrid solvent barrier and primer laminate is composed of multiple layers. Like other hybrid solvent barrier and primer layer laminates and layers, each of the layers comprises a blend of two copolyamides. In some embodiments, each of the layers comprises a different blend of the same two copolyamides. In some embodiments, each of the layers comprises a blend of the same two copolyamides, two of the blends being the same. Such a configuration may be useful, for example, in applications where the outer two layers of the three-layer laminate (e.g., first hybrid solvent barrier and primer layer 322 and third hybrid solvent barrier and primer layer 326) are blended to have excellent primer bonding performance, for example, to one or more of film substrate 310 and adhesive layer 330. In some embodiments, two layers of the hybrid solvent barrier and primer laminate comprise greater than 50% by weight of a copolyamide with tertiary amide functionality and one layer of the hybrid solvent barrier and primer laminate comprises 50% or less by weight of a copolyamide with tertiary amide functionality.

[0028] Factors that can affect the conformability of a film include the materials used to make the film, the molecular weight of those materials, the conditions to which the film is exposed (e.g., temperature, radiation exposure, and humidity), and the presence of additives in the film material (e.g., contained plasticizers, reinforcing fibers, pigments, stabilizers (e.g., UV stabilizers), and hardness-enhancing particles).

[0029] The films described herein are also extensible, meaning that they can be stretched some percentage beyond their initial dimensions without breaking or plastically deforming, in some embodiments, the films described herein are extensible to 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, or even 200% or more of their original dimensions.

[0030] The terms and expressions used are used as terms of description rather than limitation, and when using such terms and expressions, there is no intention to exclude the features shown and described or equivalents of portions thereof, and it is understood that various modifications are possible within the scope of the embodiments of the present invention. Thus, although the present invention has been specifically disclosed by specific embodiments and optional features, it should be understood that modifications and variations of the concepts disclosed herein may be employed by those skilled in the art, and such modifications and variations are considered to be within the scope of the embodiments of the present invention. EXAMPLES

[0031] Copolymer resin blends were made and coated onto cast vinyl film and laminated to a release liner coated with a pressure sensitive adhesive. Solvent barrier and adhesive properties were measured. These examples are merely for illustrative purposes and are not meant to limit the scope of the appended claims. All parts, percentages, ratios, etc. in the examples and elsewhere herein are by weight unless otherwise indicated. The following abbreviations are used herein: mil = thousandths of an inch; m = meters; cm = centimeters; °C = degrees Celsius; min = minutes; BCM = billion cubic micrometers.

[0032] [Table 1]

[0033] Examples (E1 to E12) and Comparative Examples (CE1 to CE9) Cast vinyl substrates were formed by coating an organosol onto a paper casting liner similar to or as described in Sarvetnick HA (1972) "Plastisols and Organosols" (Van Nostrand Reinhold Company: New York, NY). The ingredients included an organosol high molecular weight PVC resin homopolymer, a polymeric adipic acid plasticizer, a heat stabilizer, and titanium dioxide pigment. A silicone-coated microreplicated embossed release liner similar to that described in U.S. Pat. No. 5,296,277 was coated with an acrylic acid-containing acrylic pressure-sensitive adhesive.

[0034] A hybrid solvent barrier / primer coating solution was prepared using resins dissolved in alcohol and water. A blend of the two resins was prepared by adjusting the ratio of one to the other. The resin was dissolved in a solution containing 90 percent n-propanol and 10 percent deionized water.

[0035] The film substrate was cut into 1 inch by 5 inch (2.5 cm by 12.7 cm) sections and each was coated using a notch bar. The resin solution was drawn down using a notch bar set at a 3 mil (76 micrometer) gap between the bar and the print film. The coated film was allowed to dry in a hood for approximately 1 minute and then placed in a 40° C. oven for 1 minute. After performing the Transmission-Weighted Cup Test described below, the coated film substrate was laminated to a release liner pressure sensitive adhesive laminate and placed in a 65° C. oven to dry.

[0036] Test Method Transmission - Gravimetric Cup Test The test was derived from Society of Automotive Engineers (SAE) J2665 "Test Procedure to Measure the Fuel Permeability of Materials by the Cup Weight Loss Method". A 2" EZ-Cup Vapometer Permeability Cup was obtained from Thwing-Albert Instrument Company, West Berlin, NJ. The cup is aluminum with an aluminum threaded flange ring. The barrier coated film to be tested is held in place using a polytetrafluoroethylene gasket, a fine screen, and a coarse screen to keep the film from swelling during the test. The test is performed by partially filling the cup with methyl ethyl ketone (MEK) and then sealing the cup using the barrier coated film. The cup was placed in a 40°C oven and the cup was weighed over time. Permeability was obtained by calculating the slope of the % solvent weight loss versus time series and is a figure of merit for barrier performance. For reference, uncoated vinyl film had a permeability of 2.66% solvent loss / hour. The results are shown in Table 2.

[0037] Bonding Between Hybrid Solvent Barrier / Primer Layer and Vinyl Film The ply bond test explores the bond between the hybrid solvent barrier / primer layer and the vinyl film as a laboratory proxy for real-world peel. The film structures were evaluated for ply performance by first laminating the film to 3M 8518 Overlaminate film, cutting each sample into three 1 inch by 5 inch (2.5 cm by 12.7 cm) strips, applying the adhesive side of the film to an Alodine Q panel, and then aging in a 66°C oven for 2 hours. The film structures are peeled from the panel at 90 degrees at a speed of 500 in / min (13 m / min) using an Instron Universal Test Machine (Norwood, MA). Three 1 inch by 5 inch (2.5 cm by 12.7 cm) samples were evaluated for each hybrid solvent barrier / primer layer. The evaluation was performed on the bond site excluding the first 1 / 4 inch (0.64 cm) and inspected over the next inch (2.5 cm) (i.e., 1 / 4 inch to 1.25 inches, 0.64 cm to 3.14 cm). None of the samples delaminated the vinyl from the hybrid solvent barrier / primer layer or the hybrid solvent barrier / primer layer split, resulting in a passing rating. The results are shown in Table 2.

[0038] [Table 2]

[0039] Examples (E13-E26) Hybrid Solvent Barrier / Primer Layer - Permeation Performance and Thickness of Gravure Coated Vinyl Films All of the films in Examples E13-E26 were gravure coated at a width of 12 inches (30.5 cm) using a module manufactured by Hirano Tecseed Co. Ltd, Japan. The gravure cylinders used are listed in Table 3 below.

[0040] [Table 3]

[0041] Additional cast vinyl substrates were made using the process described above for Examples E1-E12. The vinyl film substrates were coated using different cylinders in either the forward or reverse direction, as shown in Table 4 below. All coatings were oven dried at 121° C. for 25 seconds. The transmittance (% solvent loss / time) was measured for each film using the transmittance-gravimetric cup test described above. A scanning electron microscope (JEOL JSM-7001F Field Emission Scanning Electron Microscope, Peabody, MA) was used to determine the thickness of the hybrid solvent barrier / primer layer. Sample preparation was performed by immersing the films in liquid nitrogen and fracturing them to reveal a cross-sectional view of the hybrid solvent barrier / primer layer. At least two locations were sampled for measurement, and the average thickness values ​​are shown in Table 4. Note that in Table 4, CB1 and CB1 / 2 were carbon black dispersion Hostajet Black O-PT-containing solutions at concentrations of approximately 5% and 2.5%, respectively.

[0042] [Table 4]

[0043] Examples E27-E30 and Comparative Examples CE10-CE12 Transmission Testing of Hybrid Solvent Barrier / Primer Layer-Gravure Coated Vinyl Films Using FTIR / ATR Spectroscopy Fourier transform infrared spectroscopy (FTIR) equipped with an attenuated total reflection (ATR) crystal sampling device was used to characterize the amount of solvent from ink coated onto adhesive-laminated vinyl print film that migrated through the intermediate hybrid solvent barrier / primer layer to the adhesive layer. Roland ECO-SOL MAX2 ESL4-4BK black ink was coated onto the adhesive laminated vinyl print film using a #15 Mayer Rod targeting 1.25 mil to 1.5 mil wetting, corresponding to 250% to 300% ink coverage (fill %). The ink-coated film was placed on a 52°C hotplate for 2.5 minutes to simulate the drying step of a typical inkjet printing process. The release liner was then peeled off the adhesive and the adhesive side of the film was applied to the ATR crystal.

[0044] For quantitative analysis, different ratios of ink in pressure-sensitive adhesive were prepared and analyzed at specific wavenumbers (1731 cm -1 1778cm -1 A calibration curve was first generated by tracing the peak heights of the graphic film (IJ180Cv3-10 available from 3M Company; St. Paul., Minn.) and calibrating the peak heights to the solvent weight percent composition. This calibration curve was then used to quantify the total solvent weight percent at the surface of the adhesive for a commercially printed print film (IJ180Cv3-10 available from 3M Company; St. Paul., Minn.) and a film coated with a hybrid solvent barrier / primer layer. A Nicolet iS10 Fourier transform infrared spectrometer (Thermo Fisher, 168 Third Avenue, Waltham, MA) equipped with a zinc selenide (ZnSe) multi-bounce attenuated total reflection (ATR) crystal was used to characterize the kinetics of solvent migration from the graphic film surface, through the film, across the barrier coating, and into the adhesive as a function of time.

[0045] Total solvent ink concentration data (wt%) at the adhesive side for a commercial printed vinyl film (IJ180Cv3-10, 2 mil PVC film) (no barrier) and hybrid solvent barrier / primer coated graphic films of 10 wt / wt% solutions of varying blend composition and thickness are shown in Tables 5a and 5b. The gravure cylinder BCM values ​​used to coat the hybrid solvent barrier / primer layer solutions are shown in parentheses. Examples CE10-CE12 and E27-E30 were generated using E13-E26. Examples labeled 1 layer or 2 layers represent an initial single layer coated on the film and a second layer coated, respectively. Negative values ​​are due to instrument noise at low signal-to-noise data points.

[0046] [Table 5]

[0047] [Table 6]

[0048] Examples E31-E36 Gravimetric Cup Transmission Performance (% Solvent Loss / Time) on Production Scale Vinyl Film and Coating Thickness (micrometers) Measured Using Scanning Electron Microscopy The vinyl films labeled "A" were formed as described above for Examples E1-E12. The vinyl films labeled "B" were formed as described above for Examples E1-E12, except that they also included an acrylic resin and a light stabilizer and were cast onto a polyester casting liner. The vinyl films labeled "C" were formed as described above for Examples E1-E12, except that they also included a polyester resin in the cast organosol.

[0049] Vinyl film substrates were gravure coated using a 10 wt% solution of 70 / 30 Ultramid 1C / HX2592 solution. Coatings were made using either reverse or forward gravure using either a 21.2 or 9.6 BCM gravure cylinder. Oven drying conditions were as follows: E31 was dried at 135°C for 32 seconds, E32 was dried at 135°C for 16 seconds, 93°C for 8 seconds, and 66°C for 8 seconds, E33 was dried at 135°C for 25 seconds, 93°C for 8 seconds, and 66°C for 8 seconds, E34 was dried at 135°C for 41 seconds, E35 was dried at 135°C for 41 seconds, and E36 was dried at 135°C for 41 seconds. Transmittance was determined using the gravimetric cup test described above. Thickness measurements were determined using scanning electron microscopy, sample preparation, and averaging as described above. Transmittance and thickness results are shown in Table 6.

[0050] [Table 7]

Claims

1. A stretchable, printable film comprising: a film substrate having a first major surface for receiving ink; A pressure sensitive adhesive; a hybrid solvent barrier / primer layer disposed between the film substrate and the pressure sensitive adhesive and disposed on a side of the film substrate opposite the first major surface; the hybrid solvent barrier / primer layer comprises two immiscible copolyamides; A film, wherein the hybrid solvent barrier / primer layer comprises a continuous phase of a copolyamide without tertiary amide functionality and a discontinuous phase of a copolyamide with tertiary amide functionality.

2. 2. The film of claim 1, wherein the copolyamide having tertiary amide functionality is no more than 50% by weight of the two copolyamides.

3. 2. The film of claim 1, wherein the copolyamide having tertiary amide functionality is no more than 40% by weight of the two copolyamides.

4. 10. The film of claim 1, wherein the hybrid solvent barrier / primer layer is 5 micrometers or thinner.

5. 10. The film of claim 1, wherein the two copolyamides of the hybrid solvent barrier / primer layer are soluble in a mixture of n-propanol and water or in a polar solvent.

6. 10. The film of claim 1, wherein the two copolyamides of the hybrid solvent barrier / primer layer are coextrudable.

7. The film of claim 1 , wherein the hybrid solvent barrier / primer layer comprises a pigment.

8. The film of claim 1 , wherein the film substrate comprises polyvinyl chloride or polyurethane.

9. The film of claim 1 , wherein the hybrid solvent barrier / primer layer is bonded to both the film substrate and the pressure sensitive adhesive layer.

10. 10. The film of claim 1, further comprising a layer disposed between and bonded to both the hybrid solvent barrier / primer layer and the film substrate, the layer optionally comprising a pigment.

11. The film of claim 10 , wherein the hybrid solvent barrier / primer layer bonds to the layer and to the pressure sensitive adhesive layer.

12. The film of claim 10, wherein the layer comprises an aminoethylated acrylic polymer or a crosslinked acrylic acrylate-amine copolymer.

13. 1. A method for providing a stretchable, printable film having a hybrid solvent barrier / primer layer, comprising: Providing a film substrate; coating a blend of two immiscible copolyamides onto a major surface of said film substrate to form a hybrid solvent barrier / primer layer in which the copolyamide without tertiary amide functionality is a continuous phase and the copolyamide with tertiary amide functionality is a discontinuous phase; applying a pressure sensitive adhesive onto said hybrid solvent barrier / primer layer.

14. A stretchable, printable film comprising: a film substrate having a first major surface for receiving ink; A pressure sensitive adhesive; a hybrid solvent barrier / primer laminate disposed between and bonded to both the film substrate and the pressure sensitive adhesive, the hybrid solvent barrier / primer laminate being disposed on a side of the film substrate opposite the first major surface; The hybrid solvent barrier / primer laminate comprises two layers: each of said layers of said hybrid solvent barrier / primer laminate comprises two copolyamides that are not miscible; each of said layers of said hybrid solvent barrier / primer laminate comprises a different blend of said two same copolyamides; A film, wherein each of the layers of the hybrid solvent barrier / primer laminate comprises a continuous phase of a copolyamide without tertiary amide functionality and a discontinuous phase of a copolyamide with tertiary amide functionality.

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