Patent Application
20150184037
Overlaminates may be placed over various materials, such as printing materials, to protect the underlying material from damage. In some instances, overlaminates may be placed over signs and banners having text or graphics, such as for advertising and decorations. The present invention includes overlaminates for these purposes and any other suitable purposes.
In one embodiment, the invention includes an overlaminate film. The overlaminate film may include a skin layer comprising an abrasion resistant material, a core layer comprising a blend of one or more semicrystalline polymer and ethylene vinyl acetate, and an adhesive layer. In addition, the core layer may be positioned between the skin layer and the adhesive layer.
In another embodiment, the invention includes an overlaminate film. The overlaminate film may include a skin layer comprising an abrasion resistant material and an adhesive layer. In addition, the overlaminate film may include a core layer that includes a blend of (i) one or more of an amorphous olefin copolymer having either a glass transition temperature (Tg) in the range of about 20° C. to about 70° C. (including each intermittent value therein), or a semicrystalline olefin copolymers having a melting point in the range of about 20° C. to about 70° C. including each intermittent value therein), and (ii) a polyolefin. The core layer may be positioned between the skin layer and the adhesive layer.
The following description illustrates one or more embodiments of the invention and serves to explain the principles and exemplary embodiment of the invention.
Reference will now be made in detail to exemplary embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention and not by limitation of the invention. It will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. In addition, the use of reference characters with the same two ending digits as other reference characters to indicate structure in the present specification and drawings, without a specific discussion of such structure, is intended to represent the same or analogous structure in different embodiments. Unless otherwise indicated herein, all percentages used for a component refer to the percentage by weight.
In some embodiments, the present invention includes a film overlaminate. In some embodiments, such overlaminates may include at least one skin layer that is an abrasion resistance layer, at lease one core layer, and at least one skin layer referenced as an adhesive layer. By way of example to an illustrative embodiment,
As indicated above, one or more skin layers of the overlaminate may include an abrasion resistance layer. Such abrasion resistant layers may be comprised of any suitable abrasion resistant material. For example, in some embodiments, an abrasion resistance layer may include Surlyn products available from DuPont, including Surlyn 1803. Other suitable abrasion resistant materials that form or be included in the abrasion resistance layer include ethylene acrylic polymers and copolymers. In other embodiments, other suitable materials may be used that provide suitable abrasion resistance for a particular application of a film.
In some embodiments, skin layers, including abrasion resistant layers, may also include one or more matting agents (also called gloss reducers), such as DIL 3636 DP20 from A. Schulman Inc and/or Ampacet 400700D from Ampacet Corp. in amount ranging from about 1% to about 50% by weight of the total skin layer. Such matting agents may provide a matte finish to the film.
In some embodiments, skin layers, including abrasion resistant layers, may also include one or more stabilizers, such as the ultraviolet (“UV”) light stabilizer Ampacet UV 10561, which is available from Ampacet Corporation. By way of further example, a skin layer may also include free radical scavengers. Free radical scavengers, such as hindered amine light stabilizer (HALS), may be present, alone or in addition to UV light stabilizers, in an amount of about 0.05 to about two weight percent per layer, and the UV light stabilizers, such as benzophenone, can be present in amounts ranging from 0.1 to about 5 weight percent per layer. Such ultraviolet light stabilizers and/or free radical scavengers may be included in some or all of the skin layers of a particular embodiment.
In addition, one or more skin layers of the present invention may also include and one or more process aids, such as Ampacet 10919 available from Ampacet Corporation. Furthermore, in some embodiments, one or more skin layers may include a flame retardant compound. By way of example, such a flame retardant may include FRC-2005 (which is a flame retardant and ultraviolet stabilizer that is available from Polyfil Corporation).
Similarly, one or more skin layers of the present invention may also or alternatively include heat stabilizers. Heat stabilizers may include Ferro 1237, Ferro 1720, and Synpron 1163, all available from Ferro Corporation Polymer Additives Division, and Mark V 1923, available from Witco Corp. By way of example, heat stabilizers may be present in an amount from about 0.2 to about 0.15 percent by total weight of a print layer, including each intermittent value therein. In embodiments having multiple skin layers, such heat stabilizers may be included in some or all of the skin layers.
In some embodiments of the present invention, an overlaminate may include at least two skin layers. In addition, some embodiments may include at least two skin layers that are abrasion resistant layers. Other embodiments may have more than two skin layers, wherein some or all of such additional skin layers may optionally be abrasion resistant layers. In addition, as set forth herein, some embodiments may also include a top coating.
Laminates of the present invention may also include at least one core layer. As shown in
In still other embodiments, other suitable compositions may be used for one or more layers of a core layer. For example, in one particular embodiment, a core layer may be formed from or comprised of a blend of (i) an amorphous olefin copolymer having a glass transition temperature (Tg) in the range of about 20° C. to about 70° C. (including each intermittent value therein), and/or a semicrystalline olefin copolymer having a melting point in the range of about 20° C. to about 70° C. (including each intermittent value therein), and (ii) a polyolefin, such as, for example, polypropylene. Any suitable amorphous olefin copolymer may be used. For example, in some embodiments, cyclic olefin copolymers (COC), such as Topas 9903 D-10 with a Tg of 33° C., which is available from TOPAS Advanced Polymers, may be used as a suitable amorphous olefin copolymer. For example, in some embodiments, ethylene polypropylene copolymer, such as Versify 2300 melting temperature of 66° C., which is available from Dow Chemical, may be used as suitable semicrystalline olefin copolymer. Such layers—comprised of a blend of (i) an amorphous olefin copolymer having either a glass transition temperature (Tg) in the range of about 20° C. to about 70° C. (including each intermittent value therein), and/or a semicrystalline olefin copolymer having a melting point in the range of about 20° C. to about 70° C. including each intermittent value therein), and (ii) a polyolefin—may comprise the entire core layer, one layer of a multilayer core layer, or multiple or all layers of a multilayer core layer. By way of example, in certain embodiments of the present invention, core layers may comprise about 5 to about 100 percent by weight of an amorphous olefin copolymer and about 0 to about 95 percent by weight polyolefin. In some embodiments, core layers may comprise at least about 20 percent by weight of an amorphous olefin copolymer.
Core layers of the present invention may also include other components. For example, some or all layers of a core layer may include one or more ultraviolet light stabilizers, one or more free radical scavengers, one or more process aids, one or more heat stabilizers, and/or one or more flame retardants. Such components may be included a core layer as described above with respect to the skin layers.
In some embodiments of the present invention, a core layer may have multiple layers. For example, in some embodiments, a multilayer core layer may have three layers, such as a first core layer, a second core layer, and a third core layer. By way of example, a second core layer of a multilayer core layer may be located between a skin layer, such as an abrasion resistance layer, and a first core layer, and a third core layer of a multilayer core layer may be located between the first core layer and the adhesive layer. The second core layer and the third core layer may each have the same composition of the first core layer in some embodiments, and in other embodiments the second core layer and/or the third core layer may have distinct compositions from the first core layer. In some embodiments, the second core layer and/or the third core layer may be less thick than the first core layer and/or may (each or collectively) constitute a lesser weight percentage of a film than the core layer.
For example, in one embodiment, the middle layer of a three-layer core layer may be a blend of medium density polyethylene with ethylene vinyl acetate, and the outer layers of the three-layer core layer may be a blend of blend of high density polyethylene and ethylene vinyl acetate. In still other embodiments, a multi-layer core layer may have multiple adjacent layers having the same composition as a central layer of the core layer.
Using film compositions as described herein, certain overlaminate embodiments of the present invention may be suitably rigid at room temperature for handling purposes. In addition, certain overlaminate embodiments of the present invention may provide sufficient structural behavior such that at increased temperatures tunneling does not substantially occur or does not occur, as described in more detail herein.
As indicated above, overlaminates of the present invention may also include an adhesive layer. Such adhesive layers may provide a surface to which any suitable adhesive may be added and may comprise any suitable material. In some embodiments, an adhesive layer may include a polymer resin, such as a low density olefin homopolymer resin. For example, Petrothene NA 324-009, available from LyondellBasell, and/or a low density or linear low density polyethylene, such as Dowlex 2036G available from The Dow Chemical Company, may be used to form an adhesive layer in some embodiments of the present invention. The adhesive layer may also include ethylene vinyl acetate. In some embodiments, the adhesive layer may also include stabilizers, such as the ultraviolet light stabilizer Ampacet UV 10561 (available from Amapcet Corporation) and/or FR-2005 (which is a flame retardant and ultraviolet stabilizer and available from Polyfil Corporation). In addition, an adhesive layer may include one or more process aids, such as Ampacet 10919. The adhesive layer may also include heat stabilizers, ultraviolet light stabilizers, and free radical scavengers as discussed above. In some embodiments, adhesive, such as a pressure sensitive adhesive, may be applied to an adhesive layer and a release liner may optionally be located adjacent to an adhesive layer, such that the release layer is suitable for removal prior to and at the time of application of the overlaminate.
Overlaminates of the present invention may be used with any suitable underlying material, such as to protect an underlying print film. A pressure sensitive adhesive may be used between the overlaminate and the underlying print film. The pressure sensitive adhesive may adhere to the adhesive layer of the overlaminate. Prior to application of the overlaminate to a print film, the overlaminate may have a releasable liner adjacent to the adhesive.
In some embodiments, overlaminates of the present invention may be substantially free of polyvinyl chloride (PVC). In other embodiments, overlaminates of the present invention may not include any PVC. In some embodiments, such substantially PVC-free or PVC-free overlaminates may be used as an overlaminate on an underlying material that does is either free or substantially free of PVC. In some embodiments, by way of example, overlaminates of the present invention may be used on an underlying material such as True Impact TMP7000 materials, available from Avery Dennison Corporation.
In one embodiment, as shown in
In still other embodiments, an overlaminate of the present invention may include a tie layer positioned between a core layer and a skin layer, such as an abrasion resistance layer. A tie layer may include ethylene vinyl acetate, and, in some embodiments, a tie layer may comprise all or substantially all ethylene vinyl acetate. In some embodiments, a tie layer may also include some or all layers of a core layer may include one or more ultraviolet light stabilizers, one or more free radical scavengers, one or more process aids, one or more heat stabilizers, and/or one or more flame retardants. Such components are described above with respects to the skin layers and may be included in tie layers in the same manner.
In addition, some embodiments of laminates of the present invention may be entirely free of polyvinyl chloride (“PVC”). In other embodiments, laminates of the present invention may be substantially free of polyvinyl chloride. In such embodiments entirely free or substantially free of polyvinyl chloride, laminates of the present invention may offer satisfactorily-similar properties to known polyvinyl chloride laminates.
Overlaminates of the present invention may be suitable for indoor and/or outdoor use. Such overlaminates may provide suitable and desirable durability, scratch resistance, gloss, conformability, tensile elongation and tensile strength for such applications. In addition, overlaminates of the present invention may have a glossy finish or a matte finish.
Overlaminates of the present invention may be applied over a print layer, which may include text and graphics such as for advertising or decoration. For example, as shown in
In some embodiments, such as due to the size of large banners or displays, an overlaminated print layer may be provided in segments that overlap to form a single display, such as shown in
The following examples further illustrate embodiments and features of the invention. The following components may be referenced in these examples:
A multilayer overlaminate film with an overall thickness of 2.5 mils was produced using a conventional 4-layer cast film co-extrusion process. Each of the four extruders (A, B, C, and D) supplied a melt formulation to a feedblock where the melts were combined to form a single molten stream consisting of four different layers. Extruder A was fed with material that formed a skin layer, also referenced as an abrasion resistant layer, Extruder C was fed with a molten layer that formed the core layer, and Extruder D was fed with the adhesive layer. As reflected in Table I, Extruder B was fed with either the same material as Extruder C that also formed the core layer or, alternatively, material that formed a tie layer. In the resulting films without a tie layer, the skin layer formed about 10% of the overall film thickness, the core layer (from Extruders B and C) formed a total of about 80% of the overall film thickness, and the adhesive layer formed about 10% of the overall film thickness. In the resulting films with a tie layer, the skin layer formed about 10% of the overall film thickness, the tie layer formed about 10% of the overall film thickness, the core layer formed about 70% of the overall film thickness, and the adhesive layer formed about 10% of the overall film thickness. For each sample, the molten stream was cast onto a cast roll with a chrome finish and an airknife at 60 Hz was used to pin the quenched film to the chrome roll. Table I shows the formulations used in the different extruders, wherein the percentages are by weight.
The laminate films from Table I were coated on the adhesive layer with adhesive S8072, which is an acrylic-based adhesive sold by Avery Dennison Corporation and which also is used in the vinyl overlaminate sold by Avery Dennison Corporation under the trade name DOL 2060. The adhesive-coated films were laminated to a non-PVC print film sold by Avery Dennison Corporation as Truelmpact (TMP) 7000 series, which has S-8072 adhesive on its back surface. One segment of overlaminated print film was applied on a surface coated automotive panel using a soft squeegee to ensure that an intimate contact was made between the graphic laminate and the substrate, then another segment of overlaminated print film was applied on the same panel such that an overlap was formed at the joint area as illustrated in
Each laminated panel sample was left at room temperature for at least twenty-four hours before being tested for tunneling to ensure the strong adhesion build-up between film and panel. Tunneling was known to result after temperature cycling as described above.
Tunneling testing was done by placing the samples in an oven that was preheated to 70° C. The samples were left in the oven for at least thirty minutes and were examined for any sign of tunneling. After the initial assessment, the samples were placed in the oven for at least twenty-four hours before a second evaluation. Films were examined with a seam orientation in the machine direction and with a seam orientation in the cross direction, as illustrated in
As shown by the results in Table II, tunneling was not observed at the seam of laminate samples (in either the machine direction or cross-direction samples) having ethylene vinyl acetate in the core layer.
In this example, Sample 7 had the same formulation and was prepared in the same manner as Sample 1. Sample 7 was compared with commercially-available products for tunneling properties. The commercially-available products are shown in the table below. The Avery Dennison samples, namely DOL 2060, TOL 7060, and PE85, are available from Avery Dennison Corporation. The 3M 8548 Envision Gloss sample is available from 3M. Except for the 3M 8548 Envision gloss sample (which includes an adhesive), each sample was coated with an adhesive before being laminated over Truelmpact (TMP) 7000 (also available from Avery Dennison), which also was coated with the same adhesive. Each laminate was then applied onto a coated metal panel as described in Example I. The results are provided in Table III using the same ranking scale provided above.
As shown from the results in Table III, DOL 2060 and 3M 8548 Envision Gloss (which is a polyurethane film) show similar performance in tunneling as Sample 1. However, the samples of PE 85 and TOL 7060 both show severe tunneling under the testing conditions.
Comparison testing between an overlaminate of the present invention and commercially-available products was also done to determine modulus and tensile properties. The modulus of each film was tested using Dynamic Mechanical Analysis from TA Instruments, and the samples were scanned from −50° C. to 150° C. at 1 Hz. The modulus results are shown in Table IV below and, as shown, the samples that showed no tunneling have a lower modulus at 70° C. as compared to the samples that showed tunneling.
In addition, the tensile properties of those films were measured at room temperature and at 70° C. using Instron equipped with a temperature control chamber. The results are also shown in Table IV below. From these results, it may be observed that the samples that did not result in tunneling had a lower a lower modulus at 70° C. than the samples that did result in tunneling. In addition, a digital mechanical analysis (DMA) curve was prepared as shown at
In this example, film structures were created using the same process as described in to Example I but using a five-layer feedblock and five extruders. The formulation for each extruder is provided in Table V below, and the layers of the film were positioned in the order provided in the table. The films of this example were created to increase the modulus at room temperature while maintaining a low temperature modulus at elevated temperatures.
The films of Example III were coated with adhesive S8072, available from Avery Dennison Corporation, as described in Example I. The samples were then tested for tunneling using the test procedure described in Example I. The results are reported in Table VI below, and it was observed that the addition of ethylene vinyl acetate to the core layer and the adhesive layer minimizes tunneling during the thermal cycling of the laminate. However, in some embodiments, suitable results with minimal or no tunneling may be obtained by the inclusion of ethylene vinyl acetate only in the core layer.
The films of Example III were also tested for flammability based on European Standard EN 13501-1. For this testing, a strip measuring one inch strip by 6 inches was laminated to an aluminum panel, and the laminated strip was exposed to a burner for 30 seconds and then removed. A laminate was considered a pass if the entire laminate did not burn completely or if the flame did not grow larger than 6 inches. As indicated in Table VI above, all of the samples of Example III passed the burn test.
The optical and tensile properties of the overlaminate films of Example III also were compared with the current overlaminate product available from Avery Dennison as TOL 7060. The results are shown in
In this example, film structures were extruded in the same manner as described above for Example I, and the formulation for each layer is provided in Table VII below. The Tg of Topas 9903 D-10 is 35° C. and the Tg of Topas 9506F-04 is 65° C.
Each film was adhesive coated with S8072, an adhesive sold by Avery Dennison Corporation, and the films were then laminated to a Truelmpact 7000 print layer, which is sold by Avery Dennison Corporation. The samples were mounted onto a coated automotive panel substrate such that an overlap was created between two segments of overlaminated print film. The overlaminates were tested for tunneling as described above and mechanical properties were determined using Instron as described in previous examples. The results are provided in Table VIII below.
From the results in Table VIII, it was observed that including amorphous olefin copolymers having a Tg above 25° C. and below 70° C. improved the room temperature tensile properties of the film, which are essential for handling during application and also reduce or eliminate tunneling when the film is exposed to elevated temperature conditions like 70° C. Without intending to be bound by theory, it is believed that the reduction of tunneling is due to significant modulus decrease resulted from softening of the amorphous olefin copolymer 70° C.
The modulus values measured at room temperature and at 70° C. of certain formulations from Example III and Example IV reported below in Table IX.
As shown in the results in Table IX, the films tested did not show any tunneling. Notably, the modulus at 70° C. for each of these films was significantly lower than the corresponding modulus for films that demonstrated tunneling in other examples.
In some embodiments, overlaminates of the present invention may also include or have applied thereto a top coating. Such top coatings may be one layer and applied to the overlaminate, such as adjacent to the skin layer. Top coatings may be comprised of any suitable materials. In certain embodiments, top coatings may comprise polymers containing acrylic, ester, urethane, or blends thereof. The top coating may enhance the adhesion at the seaming area of overlapping segments (as illustrated in
Two different rolls of films made in were used in this example. For a first roll, the skin layer (surlyn) was prepared according to the formulation of Sample 9 and was then corona treated to 50-52 dynes. Then, the film was coated with a top coating, which is used particularly in the product Fasson 2 Mil Clear BOPP TC available from Avery Dennison Corporation (Spec#78148). For the second roll, the film was prepared using the formulation of Sample 8. Then, the film was passed through a flame treatment at 100 ft/min to treat the skin (surlyn) layer, and the surface energy of the treated film was measured to be 58 dynes. Both the coated and flame-treated films were then coated with pressure sensitive adhesive to the adhesive layer and laminated with liner. The adhesive and liner used were the same as those used in Avery Dennison's commercially available D0L2060 gloss products. Samples were taken from both rolls and laminated with True Impact (TMP) 7000 materials, available from Avery Dennison Corporation.
Each sample was then placed on the roof and side panels of a car to create an overlap as illustrated in
It was observed that the adhesion of an the seaming area of overlap film to the surface of the overlaminate film was improved by either coating the film with TC coating or flame treatment, and such coatings did not affect the resistance of the film to tunneling. Other coatings that may be suitable include, without limitation, coatings such as Neorez waterborne coatings sold by DSM and acrylic coatings sold under the tradename NeoCryl by DSM.
Embodiments of the present invention may used for any suitable purpose. In some embodiments, films of the present invention may be used as overlaminates for signs, posters, banners, vehicle signage applications, and other printed materials. As described above, embodiments of overlaminates of the present invention may be used on materials for indoor and/or outdoor display. In addition, as demonstrated by the examples above, films of the present invention may desirably avoid tunneling effects in some embodiments.
In addition, films of the present invention may be prepared using any suitable process. By way of example, films of the present invention may be prepared using cast film processes, blown film processes, and extrusion and coextrusion processes.
These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and it is not intended to limit the invention as further described in such appended claims. Therefore, the spirit and scope of the appended claims should not be limited to the exemplary description of the versions contained herein.
The present application claims the benefit of U.S. Provisional Application No. 61/921,571 filed on Dec. 30, 2013, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61921571 | Dec 2013 | US |
