WO2001040395A1

WO2001040395A1 - Thermal laminating film

Info

Publication number: WO2001040395A1
Application number: PCT/US2000/031811
Authority: WO
Inventors: David R. Thomas; Ted B. Hoerig; John V. Corrigan
Original assignee: D & K Custom Machine Design, Inc.
Priority date: 1999-11-30
Filing date: 2000-11-17
Publication date: 2001-06-07
Also published as: AU1922501A

Abstract

A thermal laminate film is provided for protecting a substrate from damage or alteration, and preferably maintaining the readability of the substrate through the laminate as well. The disclosed film includes a first adhesive layer contacting an over-laminate layer, and a second adhesive layer contacting the first adhesive layer and the substrate. The second adhesive layer preferably includes a material having an amount of maleic anhydride to increase adhesion of the second adhesive layer to the substrate. The over-laminate layer is selected from the group including polyproylene, nylons, and polyethylene terephthalate. Individually these materials provide varying degrees of tensile, tear, and impact strengths, abrasion resistance, and flexibility. The over-laminate layer should be selected after considering the application and the desired characteristics (including aesthetic features) measured against the material qualities.

Description

THERMAL LAMINATING FILM

Technical Field Of The Invention

The present invention relates to the field of thermal laminating film. Particularly, the present invention relates to an improved adhesive layer in multilayered laminating films.

Background Of The Invention

Thermal lamination of film is the process of combining two or more plies of mateπal, typically onto a substrate of a metallic or non-metallic (e.g., paper, plastic, fibrous, non-woven fabπc, etc.) mateπal, by continuously heating the substrate or film just beyond the melting point of contacting layers to bond each ply together into a new composite. The new composition is designed to possess unique properties not found in any of the constituents.

Laminated plastic identification cards are in widespread use by a vaπety of different entities; governmental bodies and corporations regularly issue hundreds of thousands of such identification cards annually. In most instances, the identification card compπses a paper or plastic insert to which an identification image (e.g., a photograph, handwπtten legend, typewritten data, etc.) has been applied, sandwiched between two transparent protective plastic films that are then sealed together under heat and pressure. The protective coveπng sheets or films are frequently of a composite construction, each having an outer surface layer of a hard, tough, abrasion-resistant polyester, polyamide, or the like, and an inteπor surface layer of polyethylene or other heat-and-pressure sealable resin. Generally, oπented polyethylene terephthalate (OPET), biaxially-oπented polypropylene (BOPP), and biaxially-oπented nylon (BON) are used in thermal lamination applications. Standard adhesive used to marry laminate sheets together or to a substrate include polyethylene, ethylene/vinyl acetate copolymers, and cthylene/ethyl acetate copolymers. A goal is to produce less expensive adhesives, which are clear, have improved bending πgidity, and can be run under present production conditions. It would also be advantageous to produce an adhesive having a lower melt temperature to allow lamination to be run at higher speeds.

One recurπng problem in the manufacture of laminated plastic identification cards is delamination occurπng between the core or data sheet within the two protective outer resin films. A variety of different arrangements have been proposed to obtain the necessary bond so that the cover sheets will afford maximum protection to the core sheet. Nevertheless, this particular difficulty continues to recur, especially in systems in which identification cards are produced on an individual basis

For example, with a dπver's license or an identification card used for admission of an individual to a sensitive area, the core or insert may include a photograph In some systems, all of the identification data on the insert is reproduced by photography Delamination of the card may result in lost or compromised data, requiπng reissue of the license or entry card. Protection of the core identification card while still providing readability of the information container thereon is the pπmary objective of the laminate. Another continuing problem with laminated resin identification cards pertains to secuπty. Here again, a number of different expedients have been proposed to protect the cards against the usual technique for alteration, which entails careful splitting of the two cover sheets from each other to expose the core sheet so that the data on that sheet can be altered. Some of these expedients work quite well, and others are less effective, but virtually all entail additional cost.

One example of the attempts made by those in the art is presented in U.S. Pat. No. 3,918,188 to Drawer et al. In the laminating pouch construction descπbed in the ' 188 patent, two sheets of protective film mateπal are joined along one edge to form a substantially V-shaped pouch Two film sheets are each precision cut to form a center panel connected to a πm by a plurality of frangible bπdges; the two panels are maintained in accurate registry with each other. An identification card core, bearing appropriate ID data, is inserted into this pouch, after which the two protective sheets are sealed together under heat and pressure. The central portion of the pouch, comprising the two sealed center panels, is then broken out and affords the desired identification card. This arrangement is quite good, in many applications, for maintaining effective alignment of the core within the pouch. On the other hand, it does not provide for a substantial improvement in security as compared with a number of other known arrangements.

Summary Of The Invention

In accordance with the present invention, a new thermal laminate film is provided for protecting a substrate from damage or alteration, and preferably maintaining readability of the substrate through the laminate as well. One embodiment of the disclosed film includes a first adhesive layer contacting an over- laminate layer, and a second adhesive layer contacting the first adhesive layer and the substrate. The second adhesive layer preferably includes a suitable material having an amount of maleic anhydride to increase adhesion of the second adhesive layer to the substrate.

In a preferred embodiment, the over-laminate layer is selected from the group including polypropylene, nylons, and polyethylene terephthalate. Individually these materials provide varying degrees of tensile, tear, and impact strengths, abrasion resistance, and flexibility. The over-laminate layer should be selected after considering the application and the desired characteristics (including aesthetic features) measured against the material qualities. It is an aspect of the present invention to provide an adhesive layer wherein the amount of maleic anhydride is within the range of from about 0.01% to about 1.5% by weight, based on the weight of the adhesive layer. More preferably, the amount of maleic anhydride is within the range of from about 0.05% to about 0.5% by weight, based on the weight of the adhesive layer. Most preferably, the amount of maleic anhydπde is within the range of from about 0.1% to about 0.3% by weight, based on the weight of the adhesive layer.

The mateπal of the adhesive layer preferably has a melt index withm the range of from about 2 to about 200 g/ 10 min. More preferably, the adhesive layer has a melt index within the range of from about 5 to about 40 g/10 min. Most preferably, the adhesive layer has a melt index within the range of about 11 g/ 1 Omin to about 30 g/ 10 min.

In a preferred embodiment, as it is an aspect of the present invention to provide outstanding durability and physical strength, the mateπal of the second adhesive layer comprises an ethylene/vinyl acetate (EVA) copolymer. The EVA preferably has a VA content within the range of from about 5% to about 40% by weight, more preferably from about 7% to about 30%, based on the total weight of the EVA.

In another preferred embodiment, the mateπal of the second adhesive layer compπses an ethylene/methyl acrylate (EMA) copolymer. The EMA preferably has a MA content within the range of from about 18% to about 22% by weight, based on the total weight of the EMA.

Still another embodiment of the present invention provides an ethylene/n-butyl acrylate (EnBA) copolymer as the second adhesive layer. The nBA content of the mateπal being preferably in the range of from about 18% to about 22% by weight, based on the total weight of the EnBA.

These and other aspects of the present invention set forth in the appended claims may be realized in accordance with the following disclosure with particular reference to the accompanying drawings.

Descnption Of The Drawings

In the appended drawing figures

FIGURE 1 is a side-elevational view of an embodiment of the present invention showing an over-laminate layer and two adhesive layers, the outer of which is contacting a substrate; FIGURE 2 is a side-elevational view of an embodiment of the present invention showing an over-laminate layer and a single adhesive layer contacting a substrate;

FIGURE 3 is a side-elevational view of one embodiment of the present invention showing an over-laminate layer and an indeterminate number of adhesive layers, the outer of which is contacting a substrate,

FIGURE 4 is a graphical illustration of the adhesion force of a single adhesive compaπng different additives and additive concentrations; and

_ FIGURE 5 is a graphical illustration of the adhesion force of a several adhesives comparing different melt indexes

Detailed Descnption of Preferred Embodiment

While the invention is susceptible of embodiment in many different forms, this disclosure descπbes, in detail, preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiments illustrated.

Referπng generally to the appended FIGURES 1-3, the thermal laminate film of the present invention can be more readily understood The disclosed film is generally referenced by the number "10" in the following disclosure and drawings

Other components are similarly and consistently numbered throughout While the present invention is particularly designed for thermal lamination of a substrate via an automatic laminator— such as, for example, the SYSTEM 3215™, the HS DOUBLE KOTE NT™, the AUTO-KOTE™, and several other machines and their progeny manufactured by D&K International of Elk Grove Village, Illinois — other such lammators may be capable of implementation or adaptable for implementation of the system as well.

As shown in FIGURE 1, the present film 10 is formed of a protective over- laminate layer 12 and two adhesive layers first adhesive layer 14, and second adhesive layer 16. The second adhesive layer 16 contacts the first adhesive layer 14 and a substrate 20, and preferably includes a mateπal having an amount of maleic anhydπde to increase adhesion of the second adhesive layer 16 to the substrate 20. The first adhesive layer 14 binds the second adhesive layer 16 to the over-laminate layer 12.

Presently, biaxially-oπented polypropylene, biaxially-oπented nylons, and oπented polyesters, such as oπented polyethylene terephthalate (OPET), are preferred materials for the over-laminate layer. Throughout this specification, however, such materials are oftentimes referred to without an indication of their oπentation (e.g , oπented or biaxially-oπented) Nonetheless, each of these mateπals provides unique characteπstics from which to choose when deciding on the proper protective layer. Those skilled in the art would have little difficulty in choosing the proper mateπal for a specific application.

PET is a polyester mateπal having the following formula:

and suitable for most applications. It has excellent scuff and scratch resistance, durability and good folding characteπstics. PET also has high tensile, tear and impact strength, and is capable of retaining these qualities while remaining tough and flexible once applied. It may be used, for instance, on book covers, dust jackets, presentation folders, and video cartons.

Polypropylene has a good overall balance of properties and is a popular choice in the industry due to its combination of pπce and good overall characteπstics. Polypropylene has the following formula-

It is the clearest and brightest of the disclosed films and, due to its softness, polypropylene folds extremely well . Polypropylene may be applied to wπte-on/wipe- off calendars, posters, presentation folders and labels.

Nylon is a common name for polyamides, and includes such mateπals as Dacron, nylon 6 (called "Perlon"), and nylon 6,6. Nylons are typically durable mateπals with excellent scuff and scratch resistance. These film types are most commonly applied to book covers due to their "curl-free" capabilities. Other suitable mateπals duplicating or improving upon the characteπstics of the disclosed mateπals may also be suitable as a protective over-laminate layer in accordance with the present invention

With respect to the adhesive layer, a prefeπed embodiment, as shown in FIGURE 1, compπses a double-layer of adhesive. The first layer 14 being of a low density polyethylene (LDPE) or EVA and the second adhesive layer 16 preferably of an ethylene/vinyl acetate copolymer. FIGURE 2 shows an alternate embodiment using a single adhesive layer 18 of, preferably, ethylene/vinyl acetate. As previously stated, an amount of maleic anhydπde is preferably added to the adhesive polymer to improve the adhesion. Maleic anhydπde (MA) has the following structure:

The MA is added to enhance the adhesive's binding strength and stress-crack resistance, while maintaining or lowering the melt temperature of the mateπal. The

MA may be grafted or mixed with the adhesive polymer to make the adhesive more chemically reactive with polar molecules. This gives the adhesive a better "bite" duπng thermal applications.

A suitable range for the amount of MA to add to the adhesive layer 18 in order to produce the desired effect is from about 0.1% to about 10% by weight, based on the total weight of the adhesive. While higher concentrations of MA show improved adhesion results (see FIGURE 4), MA is yellow m pelletized form. Therefore, low concentrations are necessary to maintain contact claπty of the film 10. Preferably, the amount of maleic anhydπde used in the adhesive layer is within the range of from about 0.01 % to about 1.5% by weight, and most preferably from about 0.1 % to about

0.3% by weight.

The MA additive improves the adhesion force of the adhesive, as illustrated by the T-Peel Adhesion Test results shown in FIGURE 4. Identical samples of a suitable adhesive were prepared as outlined below, varying only based on the amount and type of additive used. Sample A, having no additive, acted as the control

Samples B and C were prepared with 2% and 5%, respectively, of maleic anhydπde. Samples D and E were prepared with 2% and 5%, respectively, of polyethylene terephthalate. Sample F was prepared with 5% EVOH. All the MA samples performed better than the control and other additives, with the Sample C (5% MA) performing slightly better than Sample B (2% MA).

TEST #1 - T-Peel Adhesion Test

The T-Peel Adhesion Test is performed to test both the adhesion of the film to film bond (Procedure A, below) and the film to paper bond (Procedure B, below). Procedure A (film to film)- 1) Obtain a sample of a coated roll from the extruder operation;

2) Take three samples from the left, center, and πght sides of the coated roll, making sure the sample is approximately 8 inches (20.3 cm) long by 2 inches (5.1 cm) wide;

3) Fold each sample lengthwise, placing the adhesive side toward adhesive side;

4) Pre-heat a heat sealer, such as a Sencorp Heat Sealer, by engaging for one heat cycle;

5) Insert folded samples, one by one, into the heat sealer and engage sealer according to the following table based on the film thickness: less than 3 mil = 0.5 sec. dwell time 3 mil. to 7 mil. = 1.0 sec. dwell time > 7 mil. thick = 1.5 sec. dwell time standard temperature = 240 °F (115.6 °C) standard pressure = 20 psi @ heat sealer jaw; 6) Insert sealed sample into a cutter, such as a JDC 1 " Precision Cutter, such that the edges of the heat seal are peφendicular to the cut. The result will be a one square inch (6.5 cm²) test area;

7) Repeat steps 5 and 6 for remaining samples, _ 8) Clamp test sample into Kayeness Combi-Tester with the heat seal area pointing up,

9) Make sure the force gauge is zeroed;

10) Pull the sample apart at a speed of 5.0 in/min (12.7 cm/min) while holding the "tail" of the sample approximately 90° to the direction of the pull;

11) Record the maximum reading on the force gauge in grams/m.; 12) Repeat steps 8 through 11 for remaining samples; and

13) Calculate average of readings.

Procedure B (film to paper)-

1) Obtain a sample of a coated roll from the extruder operation; 2) Take three samples from the left, center, and πght sides of the coated roll, making sure the sample is approximately 4 inches (10.2 cm) long by 2 inches (5 1 cm) wide;

3) Cut three 4" x 2" (10.2 cm x 5.1 cm) swatches of manila paperboard;

4) Position and apply the adhesive side of the film samples to the paperboard swatches;

5) Pre-heat a heat sealer, such as a Sencoφ Heat Sealer, by engaging for one heat cycle,

6) Insert samples, one by one, into the heat sealer (paper side down with film on top of paper) and engage sealer according to the following table based on the film thickness less than 3 mil = 0.5 sec. dwell time 3 mil. to 7 mil. = 1.0 sec. dwell time > 7 mil. thick = 1.5 sec. dwell time standard temperature = 240 °F (115.6 °C) standard pressure = 20 psi @ heat sealer jaw;

7) Insert sealed sample into a cutter, such as a JDC 1 " Precision Cutter, such that the edges of the heat seal are peφendicular to the cut. The result will be a one square inch (6.5 cm²) test area;

_ 8) Repeat steps 5 through 7 for remaining samples; 9) Clamp sample into Kayeness Combi-Tester with the heat seal area pointing up and the paper secured to the stationary clamp of the tester;

10) Make sure the force gauge is zeroed;

1 1) Pull the sample apart at a speed of 5.0 in/min (12.7 cm/min) while holding the "tail" of the sample approximately 90° to the direction of the pull; 12) Record the maximum reading on the force gauge in grams/in.;

13) Repeat steps 8 through 11 for remaining samples; and

14) Calculate average of readings.

Several polymers, copolymers, and polymer blends may be used as the adhesive layer 18 in the present invention. Where multiple adhesive layers are used, as shown in FIGURES 1 and 3, it is preferable that the outer adhesive layer 22 is selected from the group of copolymers including ethylene/vinyl acetate (EVA), ethylene/methyl acrylate (EMA), ethylene/n-butyl acrylate (EnBA), ethylene/ethyl acrylate (EEA), and polymer blends thereof. Most preferably, the outer adhesive layer 22 is EVA with a vinyl acetate (VA) content within the range of about 5% to about

40%) by weight. The VA content of the EVA layer is more preferably within the range of from about 10% to about 30% by weight.

With EMA, EnBA and other copolymers, the ratio of monomers may be different than that for EVA. Preferably, the methyl acrylate and n-butyl acrylate content in the ethylene copolymers, respectively, are within the range of from about 18% to about 22%o by weight.

Regardless of the adhesive used, it is desirable that the mateπal have a melt index within the range of from about 2 to about 200 g/10 min. Preferably, the melt index of the adhesive is within the range of from about 5 to about 40 g/10 mm., with about 1 1 g/10 mm. to about 20 g/10 min. being the most preferred range for the adhesive layer melt index. FIGURE 5 illustrates the affects of melt index on the adhesion force (N/25mm) using the T-Peel Adhesion Test, as explained above Clearly, loweπng the melt index in the 16%, 18%, and 28% VA samples elevated the adhesion force of the mateπal The melt index also affects how fast the film 10 can be produced, as explained below

The present invention, m an alternative embodiment, may balance the MA content, copolymer ratio, melt index of the adhesion layer, and vaπous other factors to produce an adhesion force of sufficient effectiveness. This effectiveness may be balanced against cost, contact claπty, and other negatively affected characteπstics of the film. For most applications, the adhesion force of the adhesive layer 18 is preferably at least about 60 N/25 mm. For more demanding applications, the adhesion force of the adhesive layer 18 is preferably at least about 70 N/25mm. TEST #2 - Polaroid Test A second test, known as the Polaroid Test, is used to test the seal and adhesive quality on thermal laminate films. The test is conducted in the following manner

• Select samples of pouches — folded laminating film which seals on three of four sides — to be tested;

• Insert paper card (e.g., business card) into each pouch, cutting pouches to size if necessary;

• Mark each sample;

• Process the samples through a properly warmed up laminator, such as the LX4 or LX12 made and sold by D&K International of Elk Grove Village, IL,

• Allow laminated pouches to set for a minimum of 20 hours; • Place the samples in a pressure cooker on a rack above approximately 8 oz. (125 cc.) of cold tap water;

• Seal the lid of the cooker and place in an oven set to 160°F ± 2°F (71 °C ± 1 °C) for five days;

• Remove the samples from the cooker at the end of the fifth day and place them in a clean rust-free one-gallon can (paint cans are suitable);

• Add 30 cm³ of cold tap water to each can used (approx. 15 to 20 cards to a can);

- • Add approximately 20 to 50 grams of builder's sand to each can used;

• Seal each can firmly and clamp to a shaker (e.g., a paint can shaker) orienting the can on its side;

Note: After removal from the oven, the steps until and including sealing and shaking the can should be done quickly to avoid a "re-sealing" of the softened material.

• Shake for three hours at room temperature;

• Remove samples from the can(s) and gently rinse under cool running water to remove excess sand; and

• Gently dry and examine each sample pouch for delamination.

TABLE 1 below clearly illustrates improved results using MA modified adhesive over the prior art adhesive laminates. A sample passes the test if the percent delamination is less than 12%).

TABLE 1

Polaroid Test Results- % Delamination

The present film 10 is produced by extruding the adhesive layer(s) onto the over-laminate layer 12, such as PET. The over-laminate or PET layer 12 of the present invention may be produced in any conventional manner, such as a film extrusion operation. In a preferred embodiment, the PET layer 12 is produced and stored in rolls of various widths and thicknesses. Depending on the application, such over-laminate layers may be as thin as one millimeter or as thick as ten millimeters. The over-laminate roll is typically situated at one end of a production line and fed by pull rollers over a series of idler rollers toward the adhesive extruder. The pull rollers, which operate within the preferred range of about 100 to about 800 linear feet per minute (lfm), preferably maintain a controlled tension on the over-laminate layer at all times. The over-laminate layer then travels through a treatment chamber where the surface of the layer is subjected to corona treatment. The layer then immediately travels to a primer station where it is primed for accepting and bonding to an adhesive layer. The corona treatment provides improved adherence of the primer, as is well known in the art. It has been found that un-primed PET material does not bond as well with the extruded adhesive polymer.

Next, the PET layer travels over a second series of idler rollers to a heating chamber. Here the PET layer is heated to a temperature of about 178°F, below its melting point. A third set of idler rollers is traversed before the layer encounters an ozone treatment applicator. Upon passing the ozone applicator the layer is passed below an extruder containing the desired polymer adhesive, such as EVA. The adhesive is applied as a polymer melt as the PET layer is drawn beneath the extruder orifice. The melt temperature of the extruder is within the range of about 350°F to about 550°F, and the extruder pressure is kept within the range of about 500 to about 2,000 p.s.i.

The adhesive layer is applied to a desired thickness, preferably within the range of from about 1 millimeter to about 10 millimeters. Materials with higher melt indexes can be run at higher speeds because they can be extruded more easily than low melt index polymers. The two layered film is then passed over at least a first chill roller, cooling the PET layer and adhesive layer. The chill temperature is preferably within the range of from about 55 °F to about 75 °F, and most preferably the chill roller is about 65 °F.

The final product encounters an optional post corona treatment station to promote additional adhesion to a subsequent or customer's substrate, such as paper, plastic, fibrous, non-woven fabric, etc., to be laminated. Finally, the side edges of the initial product film are cut and discarded to a recycling hopper before the material is again taken up on a roll at the end of the line.

Where multiple adhesive layers are employed, subsequent extruders containing adhesive polymers and chill rollers are encountered in succession. That is, for a double-layered adhesive as shown in FIGURE 1, after passing over the first chill roller as explained above, the two-layered film is then passed beneath a second adhesive extruder which applies a second polymer melt layer to a desired thickness.

The layered film is then passed over a second chill roller to cool the two adhesive layers and the PET layer. The temperature range of the second chill roller is preferably similar to the first chill roller.

As an alternative for some applications, subsequent adhesive polymer melts may be consecutively applied before passing over a chill roller(s). This technique may result in a better bond between adjacent adhesive layers. A tandem extruder (i.e., dual extruder heads) has also been used with success to simultaneously apply adjacent layers of adhesive to the PET layer. An important advantage to such a configuration is the possibility of increased production speed. The speed increase is the result of having the use of two chill roll stations to cool the extruded material as opposed to one chill roll station for a single head extruder.

While specific embodiments have been illustrated and described, numerous modifications are possible without departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying claims.

Claims

CLAIMSWe claim:

1. A laminating film for thermal adhesion to a substrate compπsing: an over-laminate layer of a heat-sealable film; a first adhesive layer of a low-density polyethylene contacting the over- laminate layer; and a second adhesive layer contacting the first adhesive layer, the second adhesive layer including a mateπal having an amount of maleic anhydπde to increase adhesion of the second adhesive layer to the substrate.

2. The film of Claim 1, wherein the over-laminate layer is selected from the group including polypropylene, nylon, and polyethylene terephthalate.

3. The film of Claim 1, wherein the amount of maleic anhydπde is within the range of from about 0.01% to about 1.5% by weight, based on the weight of the second adhesive layer.

4. The film of Claim 3, wherein the amount of maleic anhydπde is within the range of from about 0.05% to about 0.5% by weight, based on the weight of the second adhesive layer

5. The film of Claim 4, wherein the amount of maleic anhydπde is within the range of from about 0.1 % to about 0.3% by weight, based on the weight of the second adhesive layer.

6. The film of Claim 1, wherein the mateπal of the second adhesive layer has a melt index within the range of from about 2 to about 200 g/10 min.

7. The film of Claim 6, wherein the material of the second adhesive layer has a melt index within the range of from about 5 to about 40 g/10 min.

8. The film of Claim 6, wherein the material of the second adhesive layer has a melt index within the range of from about 11 to about 30 g/lOmin.

9. The film of Claim 1, wherein the material of the second adhesive layer comprises an ethylene/vinyl acetate (EVA) copolymer.

10. The film of Claim 9, wherein the EVA has a VA content within the range of from about 5% to about 40%> by weight, based on the total weight of the EVA.

11. The film of Claim 10, wherein the VA content is within the range of from about 10%) to about 30% by weight, based on the total weight of the EVA.

12. The film of Claim 1, wherein the material of the second adhesive layer comprises an ethylene/methyl acrylate (EMA) copolymer.

13. The film of Claim 12, wherein the EMA has a MA content within the range of from about 18% to about 22%> by weight, based on the total weight of the

EMA.

14. The film of Claim 1, wherein the material of the second adhesive layer comprises an ethylene/n-butyl acrylate (EnBA) copolymer.

15. The film of Claim 14, wherein the EnBA has a nBA content within the range of from about 18% to about 22% by weight, based on the total weight of the EnBA.

16. The film of Claim 1 , wherein the adhesion of the second adhesive layer to the substrate is at least 60 N/25mm.

17. The film of Claim 1 , wherein the adhesion of the second adhesive layer to the substrate is at least 70 N/25mm.

18. A laminating film for thermal adhesion to a substrate comprising: an over-laminate layer of a heat-sealable film; and at least one adhesive layer contacting the over-laminate layer including a material having an amount of maleic anhydride to increase adhesion properties of the adhesive layer with the substrate.

19. The film of Claim 18, wherein the at least one adhesive layer comprises: a low density polyethylene layer contacting the over-laminate layer; and a copolymer having the amount of maleic anhydride and contacting the low density polyethylene layer.

20. The film of Claim 19, wherein the copolymer is an ethylene/vinyl acetate copolymer.

21. The film of Claim 19, wherein the copolymer is an ethylene/methyl acrylate copolymer.

22. The film of Claim 19, wherein the copolymer is an ethylene/n-butyl acrylate copolymer.

23. The film of Claim 18, wherein the over-laminate layer is selected from the group including polypropylene, nylon, and polyethylene terephthalate.

24. The film of Claim 18, wherein the amount of maleic anhydride is within the range of from about 0.01% to about 1.5% by weight, based on the weight of the second adhesive layer.

25. The film of Claim 24, wherein the amount of maleic anhydride is within the range of from about 0.05%> to about 0.5%> by weight, based on the weight of the second adhesive layer.

26. The film of Claim 25, wherein the amount of maleic anhydride is within the range of from about 0.1 % to about 0.3% by weight, based on the weight of the second adhesive layer.

27. - The film of Claim 20, wherein the amount of maleic anhydride is within the range of from about 0.01 % to about 1.5% by weight, based on the weight of the second adhesive layer.

28. The film of Claim 27, wherein the amount of maleic anhydride is within the range of from about 0.05% to about 0.5% by weight, based on the weight of the second adhesive layer.

29. The film of Claim 28, wherein the amount of maleic anhydride is within the range of from about 0.1 % to about 0.3% by weight, based on the weight of the second adhesive layer.

30. The film of Claim 21 , wherein the amount of maleic anhydride is within the range of from about 0.01% to about 1.5% by weight, based on the weight of the second adhesive layer.

31. The film of Claim 30, wherein the amount of maleic anhydride is within the range of from about 0.05% to about 0.5% by weight, based on the weight of the second adhesive layer.

32. The film of Claim 31, wherein the amount of maleic anhydride is within the range of from about 0.1 % to about 0.3% by weight, based on the weight of the second adhesive layer.

33. The film of Claim 22, wherein the amount of maleic anhydride is within the range of from about 0.01% to about 1.5% by weight, based on the weight of the second adhesive layer.

34. - The film of Claim 33, wherein the amount of maleic anhydride is within the range of from about 0.05% to about 0.5% by weight, based on the weight of the second adhesive layer.

35. The film of Claim 34, wherein the amount of maleic anhydride is within the range of from about 0.1 %> to about 0.3% by weight, based on the weight of the second adhesive layer.

36. The film of Claim 19, wherein the copolymer has a melt index within the range of from about 2 to about 200 g/10 min.

37. The film of Claim 19, wherein the copolymer has a melt index within the range of from about 5 to about 40 g/10 min.

38. The film of Claim 19, wherein the copolymer has a melt index within the range of from about 1 1 to about 30 g/10 min.