Multilayer film with transfer layer

Abstract

An improved multilayer film having a transfer layer is provided. The multilayer film may be laminated to another substrate, such as a film or a paper and further processed to remove a portion of the multilayer film that may not be needed in a final structure. The multilayer film comprises a transfer layer, a bonding layer, and one or more backing layers. The layered construction of the multilayer film allows for the later removal of the transfer layer at an interface of the bonding layer. This allows for the application of a relatively thin transfer layer to a surface that is not otherwise amenable to the construction of a similar layer upon its surface.

Description

MULTILAYER FILM WITH TRANSFER LAYERTECHNICAL FIELD

[0001] The present disclosure is related to a multilayer film with a transfer layer for forming laminates useful in packaging applications.BACKGROUND

[0002] There is a need within the marketplace to provide flexible packaging structures that are more sustainable. Increased sustainability may be in the form of using raw materials that are renewably resourced and / or providing an end-of-life solution that is something other than waste, such as reusable, compostable, or recyclable options. In some situations it can be difficult to provide these more sustainable packaging solutions with the required amount of materials that are considered to be sustainable while also meeting the performance demands certain packaged items require.

[0003] Generally, current flexible packaging structures are often a combination of multiple material types having specific purposes to create a cohesive structure that can be easily converted and formed into a package. Typically, this combination of materials must allow for printing and sealing while also simultaneously providing a barrier to moisture and / or oxygen that provides a protective enclosed space for packaged items. One such sustainable improvement is the use, choice, or substitution of a more sustainable material for a material that is considered to be less sustainable or not sustainable at all. In particular, the substitution of a polymer-based film or layer with a fiber-based or paper material is often considered to be a more sustainable packaging solution. Another solution may be to reduce or lessen the amount of any non-sustainable materials within a given packaging structure.

[0004] To meet the aforementioned performance demands, these more sustainable solutions often require additional modifications to impart performance to the material that may not be inherent when utilized in a sustainable solution. A good example of this is the application of moisture and / or vapor barriers to paper or fiber-based materials to enhance the barrier properties to a level similar to a non-sustainable counterpart. Often these barriers are provided through an application of a coating or through a lamination process affixing a filmic material to a surface of the paper.

[0005] Within the disclosure of WO 2024 / 054210 entitled Paper-based Packaging Films Having a Multilayer Barrier Film a method is provided to impart a compostable barrier to a paper component through the use of a transfer substrate. The transfer substrate provides a compostable polymer type multilayer barrier film that is affixed to a paper substrate. After attachment of the paper substrate, a portion of the multilayer barrier film is removed to form a final packaging structure including the paper. By using a transfer layer processing technique, a thin compostable barrier layer can be formed on a stable web, transferred to the paper to provide barrier, and then these stabilizing materials can be removed to ensure that the end product has the maximum amount of sustainable materials and thin barrier layer. Although the packaging film of this disclosure is useful and helpful, this use of compostable polymers may not be desired in all situations and particularly when compostable disposal of a given package is not desired.

[0006] The transfer method disclosed above allows for a more efficient tailoring of performance to a given structure without the bulk of additional layers and / or materials that may not be needed in the final package. As these transfer methods have evolved, improvements are needed to develop base films that are particularly adapted for processing via transfer while also providing a structure that may be reused or alternately provide for a better separation of layers during processing.BRIEF SUMMARY

[0007] The developments herein provide an improved multilayer film having a transfer layer. The multilayer film may be laminated to another substrate, such as a film, a paper, and / or a fiber-based material, and further processed to remove a portion of the multilayer film that may not be needed in a final structure. Accordingly, the multilayer film comprises a transfer layer, a bonding layer, and one or more backing layers. This layered construction of the multilayer film allows for the later removal of the transfer layer at an interface of the bonding layer. In embodiments, the transfer layer is at a first major surface and has a thickness in a range of about 1 micron to 20 micron, the bonding layer is coupled to the transfer layer with the bonding layer including a polyamide in a range of 60% to 80%, by weight, and a polyolefin in a range of 20% to 40%, by weight, and the one or more backing layers. In some embodiments, themultilayer film may include a vacuum deposited barrier layer deposited on the first major surface.

[0008] In some embodiments, the transfer layer comprises at least a pair of sublayers in a first sublayer located at the first major surface and comprising a first polyolefin and a second sublayer located directly adjacent to the bonding layer and comprising a second polyolefin. In further embodiments, a vacuum deposited barrier layer is placed on the first major surface. In still further embodiments, the first sublayer is free from particulate antiblock. In other embodiments, the second sublayer comprises a particulate antiblock. In some embodiments, the first polyolefin is selected from the group consisting of an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer, and a linear low-density polyethylene.

[0009] In some embodiments the multilayer film comprises a transfer layer at a first major surface comprising an ethylene vinyl alcohol copolymer, a cyclic olefin polymer, or a linear low-density polyethylene with the transfer layer thickness in the range of about 1 micron to 20 micron, a bonding layer coupled to the transfer layer with the bonding layer having a polyamide in a range of 60% to 80%, by weight, and a polyolefin in a range of 20% to 40%, by weight, and at least one or more backing layers. In further embodiments, the multilayer film has a vacuum deposited barrier layer on the first major surface. In some embodiments, in locations where polyamide may be disfavored, the bonding layer may be a polypropylene homopolymer layer.

[0010] In some embodiments, the disclosure provides a multilayer barrier film comprising a transfer layer of a polyolefin and having a thickness in a range of 1 micron to 20 micron, a bonding layer comprising a polyamide in a range of 60% to 80%, by weight, and a polyolefin in a range of 20% to 40%, by weight, and a barrier layer, wherein the transfer layer is between and directly coupled to each of the bonding layer and the barrier layer. In some embodiments, the barrier layer is a vacuum deposited barrier layer having a thickness less than 1 micron.

[0011] In some embodiments the disclosure provides a method for the application of thin layers to a receiving film. In a first step of this method, a multilayer film is prepared that comprises a transfer layer having a polyolefin at a first major surface, a bonding layer comprising polyamide in a range of 60% to 80%, by weight, and polyolefin in a range of 20% to 40%, by weight, and one or more backing layers coupled to thebonding layer. This multilayer film is then adhesively laminated to a receiving film or substrate with an adhesive layer between the first major surface of the multilayer film and the receiving film or substrate to produce a resultant intermediate film. This intermediate film is then further processed to separate the intermediate film at an interface of the transfer layer and the bonding layer to produce a first film comprising the receiving film, the adhesive layer, and the transfer layer and a second film comprising the bonding layer and the one or more backing layers. In some embodiments, the method includes providing the multilayer film with the transfer layer having a thickness in a range of 1 micron to 20 micron. In some embodiments, the method includes the additional step of adding a barrier layer comprising a thickness of less than 2 micron to the transfer layer prior to the adhesive laminating step, and wherein the first film further comprises the barrier layer between the adhesive layer and the transfer layer. In some embodiments, the method includes the barrier layer being a vacuum deposited barrier layer.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0012] The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings, in which:

[0013] FIG. 1 is a cross sectional view of a multilayer film with transfer layer, according to the present disclosure;

[0014] FIG. 2 is a cross sectional view of an embodiment of the multilayer film, according to the present disclosure;

[0015] FIG. 3 is a cross sectional view of an embodiment of the transfer layer, according to the present disclosure; and

[0016] FIG. 4 is a cross sectional view of an embodiment of the multilayer film attached to a substrate to form an intermediate structure, according to the present disclosure.

[0017] The drawings show some but not all embodiments. The elements depicted in the drawings are illustrative and not necessarily to scale.DETAILED DESCRIPTION

[0018] Before the disclosure is further described, it is understood that this disclosure is not limited to the particular embodiments set forth herein. Additionally, it is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0019] Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s), to the objective(s), spirit or scope of the present invention. All such modifications are intended to be within the scope of the disclosure made herein.

[0020] Unless otherwise indicated, the words and phrases presented in this document have their ordinary meanings to one of skill in the art. Such ordinary meanings can be obtained by reference to their use in the art and by reference to general and scientific dictionaries.

[0021] References in the specification to “one embodiment” indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment.

[0022] Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.Definitions

[0023] The following explanations of certain terms are meant to be illustrative rather than exhaustive. These terms have their ordinary meanings given by usage in the art and in addition include the following explanations.

[0024] As used herein, the term “and / or” refers to any one of the items, any combination of the items, or all of the items with which this term is associated - for example, “A, B, and / or C” would mean “A, B, C, A and B, A and C, B and C, or the combination of A, B, and C.”

[0025] As used herein, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential.

[0026] A combination of materials can be described as a multilayer film (e.g., a structure or a laminate). The term "layer", as used herein, refers to a building block of films. In other words, a film is built from one or more layers. A layer is a structure of a single material type or a homogeneous blend of materials. A layer may be a single polymer, a blend of materials within a single polymer type or a blend of various polymers. A layer may contain metallic materials and may have additives. Layers may be continuous with the film or may be discontinuous or patterned. Both layers and films have a relatively insignificant thickness (z-direction) as compared to their respective length and width (x-y direction).

[0027] As used herein, the term “adjacent” means that the items, such as layers of a film, are near each other, with or without intervening material, such as adhesive. As used herein, the term “directly adjacent” or “in direct contact with” means that the items are in contact with each other, without intervening material.

[0028] As used herein, the term "unoriented" or “non-oriented” refers to a monolayer or multilayer film, sheet or web that is substantially free of post-extrusion orientation. A film is unoriented if each of the layers or films that are part of the film is substantially free of post extrusion orientation. As understood in the flexible packaging industry, orientation may be the result of monoaxially oriented (machine direction or transverse direction), or biaxially oriented (machine direction and transverse direction) stretching of the film, increasing the machine direction and / or transverse direction dimension and subsequently decreasing the thickness of the material. Orientation may be impartedinto a film in either or both directions at a temperature just below the melt temperature of the polymers in the film. In this manner, the stretching causes the polymer chains to "orient", changing the physical properties of the film. At the same time, the stretching thins the film. The resulting oriented films are thinner and can have significant changes in mechanical properties such as toughness, heat resistance, stiffness, tear strength and barrier. Orientation is typically accomplished by a double and / or triple bubble process, by a tenter-frame process or an MDO process using heated rolls. A typical blown film process or cast film process does impart some stretching of the film, but not enough to be considered oriented as described herein.

[0029] As used herein the term “substrate” may be another film or it may be another material such as a paper, paper component, or other fiber and / or fiber-based material. These paper and fiber materials, may include, but not be limited to, cellulose and / or cellulose-based fibers including virgin cellulose-based fibers, recycled fibers including materials like paper fibers and craft papers, textiles, non-wovens, wood-based fibers, cotton, linen, hemp, sugar cane or sorghum commonly known as bagasse fibers, or grains. These fibers may be untreated and / or treated to provide enhancements or improvements to their inherent properties. These fibers may be provided in a plurality of dimensions / lengths including micro and nano fibrillated types, such as, but not limited to, microfibrillated and / or nanofibrillated cellulose.

[0030] As used herein, the phrase “metallized" or "metal coating" (which when applied forms the metal layer) refers to a coating that may be applied to one or both surfaces of a film by any known method such as sputtering, vacuum deposition or electroplating (all of which fall within the definition of "metallizing" the film and involve some act or method of "depositing" a continuous metal, metal oxide or metal alloy layer onto the surface of a polymer substrate). The metal used can vary, though aluminum, zinc, gold, silver or appropriate alloys of such are preferred, with aluminum or aluminum-containing alloys being particularly preferred. As will be recognized by those skilled in the art, while the metal coating predominantly consists of the identified metal (such as aluminum), amounts of other additives may be present to improve assorted physical and optical properties of the deposited metal layer. In some occasions, pure aluminum (or the metal of choice) may be used. Other additives maybe used in minor amounts such that aluminum (or the metal of choice) is the major component. Vacuumdeposition is a preferred method of metallization in terms of processing and cost.Preferred values for the average thickness of the metal coating layer are within the range of about 1.0 to 100 nanometers, with the preferred average thickness being within the range of about 3 to 25 nanometers. (1 micron equals 10. sup. -7 meters, and 1 nanometer equals 10. sup. -8 meters.) Regardless, the metal coating preferably has a thickness less than the polymer substrate on which it is deposited, preferably substantially less than said substrate. In contrast, typical metal foils used in packaging film application have a thickness of between 4.3 to 150 microns, as noted in "Foil, Aluminum" in The Wiley Encyclopedia of Packaging Technology, 2. sup. nd. Ed., by Foil Division of the Aluminum Association, Inc., pp. 458-463, which is incorporated herein by reference. For an aluminized coating layer, the key conditions are optical density (metal deposition) of approximately 0.75 to 4, preferably 1.0-3.0.

[0031] Polyethylene is the name for a polymer whose basic structure is characterized by the chain -(CH2- CH2-)n. As used herein, the term "polyethylene” includes homopolymers and copolymers of ethylene. Polyethylene homopolymer is generally described as being a solid which has a partially amorphous phase and partially crystalline phase with a density of between 0.870 to 0.980 grams per cubic centimeter. The relative crystallinity of polyethylene is known to affect its physical properties. The amorphous phase imparts flexibility and high impact strength while the crystalline phase imparts a high softening temperature and rigidity.

[0032] "Linear low density polyethylene" (LLDPE) are copolymers of ethylene with alpha-olefins having densities from 0.915 to 0.940 grams per cubic centimeter. The alpha-olefin utilized is usually 1-butene, 1-hexene, or 1-octene and Ziegler-type catalysts are usually employed (although Phillips catalysts are also used to produce LLDPE having densities at the higher end of the range, and metallocene and other types of catalysts are also employed to produce other well-known variations of LLDPEs). An LLDPE produced with a metallocene or constrained geometry catalyst is often referred to as "mLLDPE".

[0033] "High density polyethylene" (HDPE) is ordinarily used in the art to refer to both (a) homopolymers of densities between about 0.960 to 0.980 grams per cubic centimeter and (b) copolymers of ethylene and an a-olefin (usually 1-butene, 1-hexene or 1-octene) which have densities between 0.940 and 0.958 grams per cubiccentimeter. HDPE includes polymers made with Ziegler, Phillips and single site, e.g., metallocene, type catalysts.

[0034] As used herein, “barrier” or “barrier film" or “barrier layer" or “barrier material” refers to providing for reduced transmission to gases such as oxygen (i.e. containing an oxygen barrier material). The barrier material may provide reduced transmission to moisture (i.e. containing a moisture barrier material). The barrier characteristic may be provided by one or more, or a blend, of multiple barrier materials. The barrier layer may provide the specific barrier required to preserve the product within a package throughout an extended shelf-life which may be several months or even more than one year.

[0035] The barrier may reduce the influx of moisture or water through the barrier film during the shelf-life of a packaged product (i.e., while the package is hermetically sealed). The moisture vapor transmission rate (MVTR or WVTR) of the barrier film is an indication of the barrier provided and can be measured according to ASTM F1249 using conditions of 1 atmosphere, 23°C and 90% RH.

[0036] As used herein, the phrase "sealant film" refers to a portion of the packaging web surface (i.e., formed from a single layer or multiple layers) which is capable of forming a fusion bond to a second portion of a film or packaging web surface. A sealant film is capable of fusion bonding by conventional, indirect heating means which generate sufficient heat on at least one film contact surface for conduction to the contiguous film contact surface and formation of a bond interface therebetween without loss of the film integrity. Those skilled in the art will appreciate that the bond interface between contiguous inner layers preferably has sufficient physical strength to withstand the packaging process and subsequent handling, including, for example, tensions resulting from stretching or shrinking attendant with the presence of a food body sealed within a package utilizing a sealant film. Advantageously, the bond interface is preferably sufficiently thermally stable to prevent gas or liquid leakage therethrough when exposed to above or below ambient temperatures, such as those during packaging operations, storage, handling, transport, display or processing of food. Heat seals may be designed to meet different conditions of expected use, and various heat seal formulations are known in the art and may be employed with the present disclosure. For use in cook-in applications, heat seals should withstandelevated temperatures up to about 160-180. degree. F. (71 -82. degree. C.) or higher, for example, 212. degree. F. (100. degree. C.), for extended periods of time, such as up to 4 to 12 hours in environments which may range from heated humidified air to steam to submersion in heated water. Preferably, the sealant layer is heat sealable to itself, but may be sealable to other objects, films or layers, such as to a tray when used as a lidding film or to an outer layer in a lap seal or in certain tray overwrap embodiments. Also, in certain embodiments, the sealing layer is also a food contact layer. In other embodiments, the sealant layer may be adapted to provide a peelable bond interface between film surfaces without the loss of sufficient physical strength. Methods of forming a peelable bond interface in packaging films using a sealant layer or in combination with other layers are known in the art and have been described in, for example, U. S. Pat. No. RE37,171 to Busche et al. and U. S. Patent Application Publication No. 2006 / 0269707 to Berbert, which are both incorporated herein by reference. In still other embodiments, the sealant film may be further adapted to provide a peelable and resealable bond interface. Exemplary of known peelable and resealable sealant and film layers include those structures described in U. S. Patent Application Publication Nos. 2006 / 0172131 to Haedt et al. and 2007 / 0082161 to Cruz et al., which are both incorporated herein by reference.

[0037] As used herein, the term "packaging film" refers to a film capable of being formed into a package. The packaging film may be flexible, semi-rigid or rigid. A flexible packaging film may be bent or flexed into a shape and then bonded to itself or other packaging components such that the package forms a cavity and generally retains the shape. A packaging film may be capable of forming hermetic seals and may provide oxygen and / or moisture barrier properties. A packaging film has two outer surfaces defined by a length and a width.

[0038] The term "polyamide" means a high molecular weight polymer having amide linkages (-CONH-)n which occur along the molecular chain, and includes "nylon" resins which are well known polymers having a multitude of uses including utility as packaging films, bags, and casings. See, e.g., Modern Plastics Encyclopedia, 88 Vol.64, No. 10A, pp 34-37 and 554-555 (McGraw-Hill, Inc., 1987) which is hereby incorporated by reference. Polyamides are preferably selected from nylon compoundsapproved for use in producing articles intended for use in processing, handling, and packaging food.

[0039] The term "nylon" as used herein refers more specifically to synthetic polyamides, either aliphatic or aromatic, either in crystalline, semi-crystalline, or amorphous form characterized by the presence of the amide group -CONH. It is intended to refer to both polyamides and co-polyamides.

[0040] A multilayer film with transfer layer is provided. The multilayer film is provided to enable for the transfer of a predetermined portion of a layer(s) from the multilayer film to another substrate resulting in a final first film and a final second film. Referring now to FIG. 1, a multilayer film 10 is shown. Multilayer film 10 is generally constructed as a base film comprising a transfer layer 101, a bonding layer 102, and one or more backing layers 103. The transfer layer 101 is aligned at a first major surface 11 of the multilayer film 10 and has a thickness in a range of about 1 micron to 20 micron. The bonding layer 102 is coupled to the transfer layer 101 with the bonding layer 102 comprising polyamide in a range of 60% to 80%, by weight, and a polyolefin in a range of about 20% to 40%, by weight.

[0041] The multilayer film 10 comprising the transfer layer 101, the bonding layer 102, and the one or more backing layers 103 may be formed as a polyethylene-based blown film with a thickness of about 1.5 mils. To enable for the intended use of providing the transfer layer 101, the multilayer film 10 is designed for delamination with the layers specifically constructed and selected to allow for a controlled separation at an interface of the transfer layer 101 and the bonding layer 102 when desired. Accordingly, in some embodiments it is preferred that the bonding layer 102 at this interface position contacting the transfer layer 101 is a blend of nylon. One such useful blend is combination of about 70% polyamide (PA) blended with 30% polyethylene (PE). This blend ensures a high enough bond strength to allow for later processing and substrate attachment while also allowing for the initiation of a controlled delamination when desired. The transfer layer 101 may alternately be referred to as a sealing layer or sealant film as use of the transfer layer 101 can provide for sealing functionality when utilized for a package film. In some embodiments, the transfer layer 101 comprises an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer, or a linear low-density polyethylene.

[0042] The transfer layer 101 thickness is thin by industry standards and provides benefits related to the percentage of a given material in reference to the total weight of polymeric materials when utilized in a package. This has particular significance when a goal of the package is to maintain and / or provide for recyclability within a paper-based or plastics-based recycling stream. The thickness of the transfer layer 101 is provided in a range of from about 2 micron to 15 micron or within a range from about 3 micron to 8 micron. The relatively thin dimension of the transfer layer 101 is selected to maintain recyclability when utilized in a transfer process. The transfer layer 101 is preferably comprised of a non-oriented polymer morphology. In some embodiments, the transfer layer 101 comprises a composition of greater than about 90% polyolefin, by weight. In some embodiments, the transfer layer 101 comprises a metallocene catalyzed linear low density polyethylene (mLLDPE) to achieve the preferred surface characteristics. In some embodiments, the transfer layer 101 may be ionomer-based.

[0043] In further embodiments, as is shown in FIG. 2, the multilayer film 10 includes a vacuum deposited barrier layer 104 positioned on the transfer layer 101 at the first major surface 11. The vacuum deposited barrier layer 104 may be a metalized layer to provide necessary properties for forming a barrier. The vacuum deposited barrier layer 104 is selected to provide for a reduced transmission of oxygen, moisture, and / or both oxygen and moisture. Accordingly, the vacuum deposited barrier layer 104 comprises a metal, a metal oxide, and / or inorganic oxide. In some embodiments, this vacuum deposited barrier layer 104 comprises an aluminum oxide (AIOx) and / or a silicon oxide (SiOx). Although vacuum deposited layer 104 provides for a specific type of deposition, the purpose is to provide barrier upon the transfer layer 101 and therefore, this barrier can be provided in alternate processes. In some embodiments, a package utilizing the vacuum deposited barrier layer 104 upon the transfer layer 101 has an average moisture vapor transmission rate (MVTR) value (sometimes referred to as water vapor transmission rate (WVTR)) that is less than or equal to 1 g / m2 / day, measured according to ASTM F1249 using conditions of 1 atmosphere, 38°C and 90% RH. In some embodiments, the average MVTR is less than or equal to 0.1 g / m2 / day. In embodiments, the vacuum deposited barrier layer 104 is metal or metal oxide and provided in layer having a thickness less than about 0.1 micron (μm). To enable for better formation of the barrier layer 104, the transfer layer 101 selected materials haveproperties that provide a generally very smooth and glossy surface to support the later formed and deposited barrier.

[0044] An alternate embodiment of the transfer layer 101, which may be incorporated into the previous teachings and overall structure of the previous embodiments, is shown in FIG. 3. Transfer layer 101 comprises a pair of distinct layers in the form of first sub-layer 110 and second sub-layer 111. First sub-layer 110 is aligned with the first major surface 11 and positioned adjacent to the second sub-layer 111. Second sub-layer’s 111 adjacent position is opposed the first major surface 11 and includes a second major surface 12 of the transfer layer 101 opposed the first major surface 11. In the configuration of this embodiment the transfer layer 101 first sub-layer 110 and second sub-layer 111 may be comprised of polyolefin of the same type or may be comprised of a first polyolefin polymer and / or a second polyolefin polymer.Accordingly, the first sub-layer 110 may comprise a first polyolefin and the second sublayer 111 may comprise a second polyolefin. In some embodiments, the transfer layer 101 is unoriented. In some embodiments, the first polyolefin polymer is an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer, or a linear low-density polyethylene. In some embodiments, the second polyolefin polymer is a polyethylene plastomer. In some embodiments, the first sub-layer 110 is free of anti-block particles. In some embodiments, the transfer layer 101 has a thickness of about between 2 micron to 15 micron. In some embodiments, the transfer layer 101 has a thickness of about between 2 micron and 10 micron. In some embodiments the transfer layer 101 thickness is further subdivided between the first sub-layer 110 and the second sub-layer 111, wherein the thickness of at least one of the first sub-layer 110 or the second sub-layer 111 is in a range from about 1 micron to 10 micron. In some embodiments, the thickness of at least one of the first sub-layer 110 or the second sub-layer 111 is less than about 5 micron.

[0045] Referring now to FIG. 4 an intermediate structure 20 that is further processed to form a second film is shown in cross-section. Intermediate structure 20 comprises one or more backing layers 201, a bonding layer 202, a transfer layer 203, a barrier layer 204, and a receiving substrate 205. Accordingly, intermediate structure 20 is an embodiment of multilayer film 10 having barrier and coupled to receiving substrate 205. In an embodiment, the coupling is through the use of adhesive lamination, wherein thereceiving substrate 205 is adhesively laminated to the transfer layer 203 with an adhesive layer 206. In the shown configuration of multilayer film 10 utilizing the optional barrier layer 204, the structure allows for the donation of the transfer layer 203 and barrier layer 204 to the receiving substrate 205. Intermediate structure 20 further represents an intermediate step in a method of applying a thin layer and / or sealing layer(s), such as transfer layer 203, to a receiving film, such as receiving substrate 205. To form a second film, intermediate structure 20 is further processed by separating the transfer layer 203 from the bonding layer 202 at their interface to provide the second film comprising the one or more backing layers 201 and the bonding layer 202 with the remaining portion being a first film comprising the receiving substrate 205 and the transfer layer 203. Accordingly, the use and specific composition of the bonding layer 202 and transfer layer 203 in the multilayer film of the present disclosure enables for the formation of a relatively thin sealing layer upon the receiving substrate 205.

[0046] To produce a packaging film utilizing the transfer layer, or to produce a packaging film utilizing the transfer layer and barrier layer of the present disclosure, a method of construction is provided. In a first step a multilayer film comprising one or more backing layers and a transfer layer with the transfer layer having an exposed surface is provided. The multilayer film provided has the transfer layer with a thickness in a range of from about 2 micron to 15 micron and in some embodiments comprises a composition including greater than 90% polyolefin by weight. In an optional step the transfer layer exposed surface may be coated with a vacuum deposited barrier layer by a vacuum deposition process to produce a multilayer barrier film. The vacuum deposited barrier layer comprises a metal, a metal oxide, and / or inorganic oxide. At a third step, a substrate (paper-based or film-based) is attached to the vacuum deposited barrier layer of the multilayer barrier film to produce an intermediate structure. In some embodiments, the third step may be an adhesive lamination utilizing an adhesive layer positioned between the paper and the vacuum deposited barrier layer. In a fourth step, the bonding layer and the at least one or more backing layers are removed from the intermediate structure produced at the third step to yield a packaging film comprising the substrate, the vacuum deposited barrier layer, and the transfer layer. To accomplish an easy removal of the at least one or more backing layers and thebonding layer at the interface between it and the transfer layer, the materials comprising the layers are specifically constructed and selected to allow for a controlled separation at this interface. In some embodiments, a nylon blend in the bonding layer is positioned directly adjacent a polyethylene based transfer layer. In some embodiments, nylon may not be desired and the bonding layer is a polypropylene homopolymer layer.

[0047] EXAMPLES

[0048] An exemplary multilayer film with a transfer layer is shown in Table 1 below. The multilayer film of Table 1 is a 1.5 mils thick blown film having seven layers including an about 6 micron combined transfer layer. The double lines shown in Table 1 represent the interface between the transfer layer and the bonding layer of the exemplary film. Accordingly, the Red and Yellow layers in Table 1 comprise the transfer layer which is useful as a sealing layer.TABLE 1: MULTILAYER FILM

[0049] An exemplary multilayer film with a transfer layer is shown in Table 2 below. The multilayer film of Table 2 has an improved transfer layer with optimized sub-layers to provide better sealing when compared to the exemplary film of Table 1. The multilayer film of Table 2 is also a 1.5 mils thick blown film having seven layers including an about 6 micron combined transfer layer. The double lines shown in Table 2 represent the interface between the transfer layer and the bonding layer of the exemplary film. Accordingly, the Red and Yellow layers in Table 2 comprise thetransfer layer functioning as a sealant and / or the sealing layer of the multilayer film with the remaining layers comprising the bonding layer and the at least one or more backing layers.TABLE 2: MULTILAYER FILM

[0050] An exemplary multilayer film with transfer layer is shown in Table 3 below. The multilayer film of Table 3 has an alternate bonding layer comprising a polypropylene-based structure to provide a multibarrier film that is constructed without nylon to provide an alternate sustainable structure by using a majority of polyolefin -based polymers. The multilayer film of Table 3 is also a 1.5 mils thick blown film having seven layers including an about 6 micron combined transfer layer useful for sealing. The double lines shown in Table 3 represent the interface between the transfer layer and the bonding layer of the exemplary film. Accordingly, the Brown and Blue layers in Table 3 comprise the transfer layer of the multilayer film with the remaining layers comprising the bonding layer and the at least one or more backing layers.TABLE 3: MULTILAYER FILM

[0051] An exemplary multilayer film useful for a high barrier paper packaging film is shown in Table 4 below. The multilayer film of Table 4 is similar to Table 3 and has a bonding layer comprising a polypropylene-based structure to provide a multibarrier film that is constructed without nylon to provide a more sustainable structure by using a majority of polyolefin-based polymers. Compared to Table 3, the exemplary film of Table 4 includes an alternate ionomer-based transfer layer. The ionomer may be an ionomer of ethylene acid copolymer. The ionomer may be of the type having a melting point of 93°C and a melt index of 14g / 10 min according to ASTM D1238 or may be of the type having a melting point of 100°C and a melt index of 5.5g / 10 min according to ASTM D1238. The antiblock may be an antiblock compound comprising about 75 percent by weight of ethylene methacrylic acid copolymer (EMAA) or ethylene acrylic acid copolymer (EAA) and 25 percent by weight of antiblock additive. The multilayer film of Table 4 is also a 1.5 mils thick blown film having seven layers including an about 6 micron combined transfer layer. The double lines shown in Table 4 represent the interface between the sealing layer portion and base layer portion of the exemplary film. Accordingly, the Brown and Blue layers in Table 4 comprise the transfer layer and / or the sealing layer of the multilayer film with the remaining layers comprising the bonding layer and at least one or more backing layers.TABLE 4: MULTILAYER FILM

[0052] The exemplary multilayer films of Table 1 and Table 2 were metalized upon the surface of the Red layer opposite the Yellow layer. The exemplary multilayer films of Table 3 and Table 4 were metalized upon the surface of the Blue layer opposite the Brown layer. The metallization upon the above indicated surfaces comprising mLLDPE, ionomer, and EA / antiblock formed a multilayer barrier film having an MVTR of 0.1g / m2 / day. This transmission rate is comparable to a traditional metallized biaxially oriented polypropylene film.

[0053] MULTILAYER FILM WITH TRANSFER LAYER EMBODIMENTS

[0054] Embodiment A. A multilayer film comprising:

[0055] a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising a thickness in a range of 1 micron to 20 micron;

[0056] a bonding layer coupled to the transfer layer, the bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; and

[0057] one or more backing layers.

[0058] Embodiment B. The multilayer film according to Embodiment A, further comprising a vacuum deposited barrier layer on the first major surface.

[0059] Embodiment C. The multilayer film of Embodiment A, wherein the transfer layer comprises a first sub-layer located at the first major surface, comprising a first polyolefin; and a second sub-layer located directly adjacent to the bonding layer, the second sub-layer comprising a second polyolefin.

[0060] Embodiment D. The multilayer film of Embodiment C, further comprising a vacuum deposited barrier layer on the first major surface, and wherein the first sublayer is free from a particulate antiblock.

[0061] Embodiment E. The multilayer film of Embodiment C, wherein the first polyolefin is selected from the group consisting of an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer and a linear low-density polyethylene.

[0062] Embodiment F. The multilayer film of Embodiment C, wherein the second sublayer comprises a particulate antiblock.

[0063] Embodiment G. A multilayer film configured for transfer operations comprising:

[0064] a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer or a linear low-density polyethylene and a thickness in a range of 1 micron to 20 micron;

[0065] a bonding layer coupled to the transfer layer, the bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; and

[0066] one or more backing layers.

[0067] Embodiment H. The multilayer film of Embodiment G, further comprising a vacuum deposited barrier layer on the first major surface.

[0068] Embodiment I. A multilayer barrier film comprising:

[0069] a transfer layer comprising a polyolefin and a thickness in a range of 1 micron to 20 micron;

[0070] a bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; and

[0071] a barrier layer;

[0072] wherein the transfer layer is between and directly coupled to each of the bonding layer and the barrier layer.

[0073] Embodiment J. The multilayer barrier film of Embodiment I wherein the barrier layer is a vacuum deposited barrier layer and has a thickness less than 1 micron.

[0074] Embodiment K. A method of applying thin layers to a receiving substrate comprising the steps of:

[0075] preparing a multilayer film comprising a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising a polyolefin;

[0076] a bonding layer coupled to the transfer layer, the bonding layer comprising polyamide in a range of 60% to 80%, by weight and polyolefin in a range of 20% to 40%, by weight; and one or more backing layers coupled to the bonding layer;

[0077] adhesive laminating the first major surface of the multilayer film to a receiving film with an adhesive layer to produce an intermediate film;

[0078] separating the intermediate film at an interface of the transfer layer and the bonding layer to produce a first film comprising the receiving film, the adhesive layer and the transfer layer and a second film comprising the one or more backing layers and the bonding layer.

[0079] Embodiment L. The method of Embodiment K wherein the transfer layer has a thickness in a range of 1 micron to 20 micron.

[0080] Embodiment M. The method of Embodiment K further comprising a step of adding a barrier layer comprising a thickness of less than 2 micron to the transfer layer of the multilayer film prior to the adhesive laminating step;

[0081] wherein the first film further comprises the barrier layer between the adhesive layer and the transfer layer.

[0082] Embodiment N. The method of Embodiment M wherein the barrier layer is a vacuum deposited barrier layer.

Claims

CLAIMSWhat is claimed is:

1. A multilayer film comprising:a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising a thickness in a range of 1 micron to 20 micron;a bonding layer coupled to the transfer layer, the bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; andone or more backing layers.

2. The multilayer film of claim 1 further comprising a vacuum deposited barrier layer on the first major surface.

3. The multilayer film of claim 1 wherein the transfer layer comprises:a first sub-layer located at the first major surface, comprising a first polyolefin; and a second sub-layer located directly adjacent to the bonding layer, the second sublayer comprising a second polyolefin.

4. The multilayer film of claim 3 further comprising a vacuum deposited barrier layer on the first major surface, andwherein the first sub-layer is free from a particulate antiblock.

5. The multilayer film of claim 3 wherein the first polyolefin is selected from the group consisting of an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer and a linear low-density polyethylene.

6. The multilayer film of claim 3 wherein the second sub-layer comprises a particulate antiblock.

7. A multilayer film configured for transfer operations comprising:a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising an ethylene vinyl alcohol copolymer, a cyclic olefin copolymer or a linear low-density polyethylene and a thickness in a range of 1 micron to 20 micron;a bonding layer coupled to the transfer layer, the bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; andone or more backing layers.

8. The multilayer film configured of claim 7 further comprising a vacuum deposited barrier layer on the first major surface.

9. A multilayer barrier film comprising:a transfer layer comprising a polyolefin and a thickness in a range of 1 micron to 20 micron;a bonding layer comprising a polyamide in a range of 60% to 80%, by weight and a polyolefin in a range of 20% to 40%, by weight; anda barrier layer;wherein the transfer layer is between and directly coupled to each of the bonding layer and the barrier layer.

10. The multilayer barrier film of claim 9 wherein the barrier layer is a vacuum deposited barrier layer and has a thickness less than 1 micron.

11. A method of applying thin layers to a receiving substrate comprising the steps of:preparing a multilayer film comprising a transfer layer located at a first major surface of the multilayer film, the transfer layer comprising a polyolefin; a bonding layer coupled to the transfer layer, the bonding layer comprising polyamide in a range of 60% to 80%, by weight and polyolefin in a range of 20% to 40%, by weight; and one or more backing layers coupled to the bonding layer;adhesive laminating the first major surface of the multilayer film to a receiving film with an adhesive layer to produce an intermediate film;separating the intermediate film at an interface of the transfer layer and the bonding layer to produce a first film comprising the receiving film, the adhesive layer and the transfer layer and a second film comprising the one or more backing layers and the bonding layer.

12. The method of claim 11 wherein the transfer layer has a thickness in a range of 1 micron to 20 micron.

13. The method of claim 11 further comprising a step of adding a barrier layer comprising a thickness of less than 2 micron to the transfer layer of the multilayer film prior to the adhesive laminating step; wherein the first film further comprises the barrier layer between the adhesive layer and the transfer layer.

14. The method of claim 13 wherein the barrier layer is a vacuum deposited barrier layer.

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