Heat shrinkable, heat sealable food packaging wrap and method

Abstract

A heat-shrinkable bi-oriented, multi-layer laminate is described, the laminate comprising a core layer comprising: 75-85 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, 10-20 percent by weight of a linear low density polyethylene (LLDPE) and 1-10 percent by weight of ethylene-based compatibilizer; at least one surface layer comprising: 70-80 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 10-20 percent by weight of ethylene-based compatibilizer; and at least one inner layer between at the least one surface layer and the core layer, the at least one inner layer comprising: less than 70 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 10-20 percent by weight of ethylene-based compatibilizer, 10-20 percent by weight of a linear low density polyethylene (LLDPE). Methods of manufacture and use as a food packaging film are provided.

Description

Attorney Docket No.: 045389-001055HEAT SHRINKABLE, HEAT SEALABLE FOOD PACKAGING WRAP AND METHODINCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified, for example, in the Application Data Sheet or Request as filed with the present application, are hereby incorporated by reference under 37 CFR 1.57, and Rules 4.18 and 20.6, including U.S. Provisional Application Nos. 63 / 715,798, filed November 4, 2024 and 63 / 765,265, filed February 28, 2025.Technical Field

[0002] This disclosure is directed to heat shrinkable, heat sealable packaging. In examples, the heat shrinkable, heat sealable packaging is used in food production and manufacturing.BACKGROUND

[0003] Current heat shrink films, while providing adequate performance, require heat shrink temperatures that may impact production.SUMMARY

[0004] In examples, heat-shrinkable bi-oriented, multi-layer laminate is provided, the laminate comprising a first surface layer comprising: 70-80 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of ethylene-based compatibilizer; a second, opposing surface layer comprising: less than 70 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of ethylene-based compatibilizer, 10-20 percent by weight of a linear low density polyethylene (LLDPE); and an core layer positioned between the two surface layers, the core layer comprising: 75-85 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of a linear low density LLDPE, and 1-10 percent by weight of ethylene-based compatibilizer. The ethylene a-olefin polyolefin plastomer polymer of the first surface layer and the second surface layer can be the same or different. The ethylene-based compatibilizer of the first surface layer, the second surface layer, and the core can be the same or be of a different density or chemical composition.

[0005] In aspects, the ethylene-based compatibilizer is one or more of ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), ethylene butylAttorney Docket No.: 045389-001055 acrylate (EBA), anhydride modified ethylene acrylate copolymer, or anhydride-grafted copolymer of ethylene and higher olefins.

[0006] In aspects, the first surface layer comprises a remainder of less than 12 percent by weight of additives so as to total 100 percent by weight. In aspects, the second surface layer comprises a remainder of less than 2 percent by weight of additives so as to total 100 percent by weight. In aspects, the core layer comprises a remainder of less than 5 percent by weight of additives so as to total 100 percent by weight.

[0007] In aspects, alone or in combination with any of the previous aspects, the laminate is crosslinked. In aspects, alone or in combination with any other aspect, the laminate is crosslinked before orientation.

[0008] In aspects, alone or in combination with any of the previous aspects, the first and the second layers are directly adjacent the core layer. In aspects, alone or in combination with any of the previous aspects, the first and the second layers are extrusion laminated to the core layer.

[0009] In aspects, alone or in combination with any of the previous aspects, the weight of core layer is at least three times the weight of the first layer or the second layer. In aspects, alone or in combination with any of the previous aspects, the weight percent of ethylene-based compatibilizer is 5-10 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of LLDPE is 10-14 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of polyolefin plastomer (POP) is 75-85 wt. % of the total film weight.

[0010] In aspects, alone or in combination with any of the previous aspects, the heat- shrinkable bi-oriented, multi-layer laminate is devoid of polyester, polyamide, polystyrene and copolymers thereof.

[0011] In other examples, a crosslinked biaxially oriented heat shrinkable, heat sealable multilayer shrink film is provided, comprising: a first outer layer; a second outer layer; and an core layer between said first and second outer layers; the first and second outer layers each comprising a blend of between about 70 wt. % and about 80 wt. % polyolefin plastomer (POP), and between about 10 wt. % and about 20 wt. % ethylene-vinyl acetate copolymer, where the combined weight of the first and the second outer layers comprise less than about 40 wt. % of the total film weight; and the core layer comprising: 75-85Attorney Docket No.: 045389-001055 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of a linear low density polyethylene ( LLDPE), and a remainder of less than 5 percent by weight of additives including 1-10 weight percent ethylene-based compatibilizer, where the weight of core layer is at least 60 wt. % of the total film weight. In aspects, the crosslinked biaxially oriented heat shrinkable, heat sealable multilayer stretch film is heat shrinkable at a contact surface temperature range between about 160 °C to about 200 °C (about 320 °F to about 392 °F).

[0012] In aspects, alone or in combination with any of the previous aspects, only one of the first layer or the second layer comprises LLDPE polymer.

[0013] In aspects, alone or in combination with any of the previous aspects, the weight of core layer is at least three times the weight of the first layer or the second layer. In aspects, alone or in combination with any of the previous aspects, the weight percent of ethylene-based compatibilizer is 5-10 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of LLDPE is 10-14 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of polyolefin plastomer (POP) is 75-85 wt. % of the total film weight.

[0014] In aspects, alone or in combination with any of the previous aspects, the LLDPE comprises at least 30 wt. % of the at least one inner layer. In aspects, alone or in combination with any of the previous aspects, the LLDPE comprises 30-70 wt. % of the at least one inner layer.

[0015] In aspects, alone or in combination with any of the previous aspects, the crosslinked biaxially oriented heat shrinkable, heat sealable multilayer shrink film is devoid of polyester, polyamide, polystyrene and copolymers thereof.

[0016] In examples, a heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate is provided, the laminate comprising a core layer comprising an ethylene a-olefin polyolefin plastomer polymer, a linear low density polyethylene (LLDPE), and optionally an ethylenebased compatibilizer; at least one surface layer comprising an ethylene a-olefin polyolefin plastomer polymer and an ethylene-based compatibilizer; and at least one inner layer between at the least one surface layer and the core layer, the at least one inner layer comprising an ethylene a-olefin polyolefin plastomer polymer, and an ethylene-based compatibilizer, and a linear low density polyethylene (LLDPE).Attorney Docket No.: 045389-001055

[0017] In aspects, alone or in combination with any of the previous aspects, the core layer comprises an ethylene-based compatibilizer. In aspects, alone or in combination with any of the previous aspects, the at least one surface layer further comprises a linear low density polyethylene (LLDPE). In aspects, alone or in combination with any of the previous aspects, the at least one inner layer further comprises an anti-fog agent.

[0018] In aspects, alone or in combination with any of the previous aspects, the core layer comprises 65-85 percent by weight of the linear low density polyethylene, 5-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of the ethylene-based compatibilizer. In aspects, alone or in combination with any of the previous aspects, the at least one inner layer comprises 30-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a- olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer. In aspects, alone or in combination with any of the previous aspects, the at least one inner layer can further comprise 10-30 percent by weight of the anti-fog agent. In aspects, alone or in combination with any of the previous aspects, the at least one surface layer comprises 40-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer.

[0019] In aspects, alone or in combination with any of the previous aspects, the core layer comprises 65-85 percent by weight of the linear low density polyethylene, 5-25 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of the ethylene-based compatibilizer; the at least one inner layer comprises 30-55 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; 5-20 percent by weight of the ethylene-based compatibilizer; and 10-30 percent by weight of the anti-fog agent; and the at least one surface layer comprises 50-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer.

[0020] In aspects, alone or in combination with any of the previous aspects, the core layer comprises 65-80 percent by weight of the linear low density polyethylene, 10-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10Attorney Docket No.: 045389-001055 percent by weight of the ethylene-based compatibilizer; the at least one inner layer comprises 50-70 percent by weight of the linear low density polyethylene, 15-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; 5-15 percent by weight of the ethylene-based compatibilizer; and the at least one surface layer comprises 40-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a- olefin polyolefin plastomer polymer; and 5-15 percent by weight of the ethylene-based compatibilizer.

[0021] In aspects, alone or in combination with any of the previous aspects, the laminate excludes or is devoid of polyester, polyamide, polystyrene, and copolymers thereof.

[0022] In aspects, alone or in combination with any of the previous aspects, the laminate is crosslinked. In aspects, alone or in combination with any of the previous aspects, the laminate is crosslinked before orientation.

[0023] In aspects, alone or in combination with any of the previous aspects, the at least one inner layer is directly adjacent the core layer. In aspects, alone or in combination with any of the previous aspects, the at least one inner layer is extrusion laminated to the core layer and the at least one surface layer is extrusion laminated to the at least one inner layer.

[0024] In aspects, alone or in combination with any of the previous aspects, a weight of the core layer is at least three times a combined weight of the at least one inner layer and the at least one surface layer.

[0025] In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is one or more of ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), ethylene butyl acrylate (EBA), anhydride modified ethylene acrylate copolymer, or anhydride-grafted copolymer of ethylene and higher olefins. In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is ethylene vinyl acetate (EVA). In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is ethylene methyl acrylate (EMA).

[0026] In aspects, alone or in combination with any of the previous aspects, the weight percent of LLDPE is 50-75 wt. % of the total film weight. In aspects, alone or in combinationAttorney Docket No.: 045389-001055 with any of the previous aspects, the weight percent of the ethylene ct-olefin polyolefin plastomer (POP) is 15-35 wt. % of the total film weight.

[0027] In aspects, alone or in combination with any of the previous aspects, the core layer comprises a remainder of less than 5 percent by weight of additives so as to total 100 percent by weight of the core layer. In aspects, alone or in combination with any of the previous aspects, each of the at least one surface layer comprises a remainder of less than 10 percent by weight of additives so as to total 100 percent by weight of each of the at least one surface layer. In aspects, alone or in combination with any of the previous aspects, each of the at least one inner layer comprises a remainder of less than 5 percent by weight of additives so as to total 100 percent by weight of each of the at least one inner layer.

[0028] In examples, a crosslinked, biaxially oriented, heat shrinkable, heat sealable multilayer laminate film is provided comprising a first outer layer; a first inner layer adjacent the outer layer; a core layer adjacent the first inner layer; a second inner layer adjacent the core layer; and a second outer layer adjacent the second inner layer; the first and the second outer layers each comprising a blend of an ethylene a-olefin polyolefin plastomer (POP) and an ethylene-based compatibilizer; the first and the second inner layers each comprising a blend of an ethylene a-olefin polyolefin plastomer (POP) and an ethylenebased compatibilizer; and the core layer comprising an ethylene a-olefin polyolefin plastomer polymer, of a linear low density polyethylene (LLDPE), and optionally an ethylenebased compatibilizer, where the weight of core layer is at least 60 wt. % of the total film weight.

[0029] In aspects, alone or in combination with any of the previous aspects, the core layer comprises an ethylene-based compatibilizer. In aspects, alone or in combination with any of the previous aspects, the first and second outer layers further comprise a linear low density polyethylene (LLDPE). In aspects, alone or in combination with any of the previous aspects, at least one of the first inner layer and the second inner layerfurther comprises an anti-fog agent.

[0030] In aspects, alone or in combination with any of the previous aspects, the core layer comprises 65-85 percent by weight of the linear low density polyethylene, 5-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of the ethylene-based compatibilizer; the first inner layer and secondAttorney Docket No.: 045389-001055 inner layer each comprise 30-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer; and the first outer layer and second outer layer each comprise 40-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer. In aspects, alone or in combination with any of the previous aspects, the at least one of the first inner layer and second inner layer can comprise 10-30 percent by weight of the anti-fog agent.

[0031] In aspects, alone or in combination with any of the previous aspects, the laminate film is configured to heat shrink at a contact surface temperature range between about 160 °C to about 200 °C (about 320 °F to about 392 °F).

[0032] In aspects, alone or in combination with any of the previous aspects, a weight of the core layer of the laminate film is at least three times a combined weight of the first and the second inner layer and the first and the second surface layer.

[0033] In aspects, alone or in combination with any of the previous aspects, the laminate film excludes or is devoid of polyester, polyamide, polystyrene, and copolymers thereof.

[0034] In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is one or more of ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), ethylene butyl acrylate (EBA), anhydride modified ethylene acrylate copolymer, or anhydride-grafted copolymer of ethylene and higher olefins. In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is vinyl acetate (EVA). In aspects, alone or in combination with any of the previous aspects, the ethylene-based compatibilizer is ethylene methyl acrylate (EMA).

[0035] In aspects, alone or in combination with any of the previous aspects, the weight percent of LLDPE is 50-75 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of LLDPE is 55-75 wt. % of the total film weight. In aspects, alone or in combination with any of the previous aspects, the weight percent of the ethylene a-olefin polyolefin plastomer (POP) is 15-35 wt. % of the total film weight.Attorney Docket No.: 045389-001055

[0036] In aspects, a crosslinked, biaxially oriented, heat shrinkable, heat sealable multilayer laminate film is provided, the laminate film comprising: a first outer layer; a first inner layer adjacent the outer layer; a core layer adjacent the first inner layer; a second inner layer adjacent the core layer; and a second outer layer adjacent the second inner layer. The first and the second outer layers each comprising a blend of an ethylene a-olefin polyolefin plastomer (POP), an ethylene-based compatibilizer. The first and the second inner layers each comprising a blend of an ethylene a-olefin polyolefin plastomer (POP) and an ethylene-based compatibilizer. The core layer comprising a blend of an ethylene a-olefin polyolefin plastomer polymer and a linear low density polyethylene (LLDPE), and optionally an ethylene-based compatibilizer, where the weight of core layer is at least 60 wt. % of the total film weight. In examples, at least one of the first inner layer and the second inner layer further comprises an anti-fog agent.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to understand and to see how the present disclosure may be carried out in practice, examples will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0038] FIG. 1A is a schematic of an exemplary heat-shrinkable laminate film in accordance with the broadest aspect of the present disclosure.

[0039] FIG. IB is a schematic of an exemplary a heat-shrinkable package formed from the laminates of FIGs. 1A in accordance with the broadest aspect of the present disclosure.

[0040] FIG. 2 is a schematic of an exemplary process used to make a heat-shrinkable film configured to make a heat-shrinkable bag or for use in a flow wrap packaging process in accordance with the broadest aspect of the present disclosure.

[0041] FIG. 3 is a schematic of another exemplary process used to make a heat- shrinkable film configured to make a heat-shrinkable bag or for use in a flow wrap packaging process in accordance with the broadest aspect of the present disclosure.DETAILED DESCRIPTION

[0042] An improved polyolefin-type heat-shrinkable oriented stretch film suitable for use as a platen heat sealed overwrap material for food or a food tray with a low temperature sealing range and good machinability is provided. This film is characterized byAttorney Docket No.: 045389-001055 good elongation, good elastic memory, puncture resistance, abrasion resistance and heat sealable at lower temperatures.

[0043] The polyolefin multilayer film of this present disclosure requires at least three layers, two outer layers and a core or inner layer between the outer layers, has biaxial heat shrink properties and is crosslinked. Stretch recovery, abrasion resistance, and food contact acceptability of the film meets the requirements of the food packaging industry. It exhibits good machinability, overcomes the problems associated with an irradiated film, has adequate slip properties, is resistant to burn through and has no flap pull back.

[0044] The heat-shrinkable material in accordance with the present disclosure is a coextruded multi-layer film. In examples the multi-layer film comprises at least 5 layers and may be a barrier or non-barrier material. Barrier materials according to the present disclosure are those having an oxygen permeability (measured with a film having a thickness of 25 microns) lower than 300 cm3 / m224h bar, preferably lower than 10 cm3 / m224h bar.

[0045] The multi-layer material in accordance with the present disclosure is characterized in that it may be used universally, for example, both in the packaging by heatsealing (on polystyrene, polyethylene terephthalate, or polyethylene / polypropylene trays) as well as in flow-pack packaging. In particular, the material of the present disclosure may be used in conventional packaging processes, such as LID, Flow-Pack, sous-vide, Skin and L- sealer.

[0046] FIG. 1A is a schematic of an exemplary 5-layer heat-shrinkable multi-layer laminate film 100 having outer surface layers 140, inner layers 120, and core layer 130. In examples, outer surface layers 140 of the multi-layer laminate film 100 comprises 70-80 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of ethylenebased compatibilizer. In examples, outer surface layer 140 is devoid of LLDPE. In examples, outer surface layer 140 of the multi-layer laminate film 100 comprises 40-70 percent by weight LLPDE, 15-35 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 5-20 percent by weight of an ethylene-based compatibilizer. In examples, additives may comprise a remainder of less than 10% by weight so as to total 100 percent by weight of each of outer surface layer 140.

[0047] In examples, inner layer 120 comprises less than 70 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 10-20 percent by weight of ethylene-Attorney Docket No.: 045389-001055 based compatibilizer, 10-20 percent by weight of a linear low density polyethylene (LLDPE). In examples, the inner layer 120 of the multi-layer laminate film 100 comprises 30-70 percent by weight of LLDPE, 15-35 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 5-20 percent by weight of an ethylene-based compatibilizer. In examples, inner layers 120 of the multi-layer laminate film 100 can comprise 10-30 percent by weight of an anti-fog agent. In examples, additives may comprise a remainder of less than 5% by weight so as to total 100 percent by weight of inner layers 120.

[0048] In examples, core layer 130 is positioned between two inner layers 120, the core layer comprising: 75-85 percent by weight of a polyolefin plastomer polymer, 10-20 percent by weight of a linear low density polyethylene (LLDPE). In examples, core layer 130 is positioned between two inner layers 120, the core layer comprising 65-85 percent by weight LLPDE, 5-30 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of an ethylene-based compatibilizer. In examples, additives may comprise a remainder of less than 5% by weight so as to total 100 percent by weight of core layer 130. Various additives, fillers etc. can be added to any of the layers 120, 130, 140. In examples, core layer 130 is devoid of ethylene vinyl acetate copolymer or ethylene methyl acrylate copolymer.

[0049] In examples, the core layer excludes an ethylene-based compatibilizer, where the weight of the core layer is at least 60 wt. % of the total film weight. In examples, the weight of the core layer is at least 3 times the weight of eitherthe core film or combined weight of the inner and the surface layers.

[0050] In examples, the crosslinked biaxially oriented heat shrinkable, heat sealable multilayer laminate film 100 is heat shrinkable at a contact surface temperature range between about 135 °C to about 177 °C (about 275 °F to about 351 °F) at a contact time of between about 2 and about 4 seconds, and does not burn through.

[0051] The simultaneous presence of such components in the surface layers and core layer allows the multi-layer material of the present disclosure to be used universally, on any tray, in heat-sealing processes, as well as in flow-pack packaging processes. The presence of the ethylene-based compatibilizer throughout the laminate has the function of a tie-layer for all of the laminate layers and / or favoring the heat-sealing of the material at low temperature, among other benefits.Attorney Docket No.: 045389-001055

[0052] Exemplary ethylene-based compatibilizer, a material suitable for compatibilizing the skin layers to each other and / orthe core layer(s) is used. In examples, one or more ethylene-based compatibilizers, individually, comprise a molecular structure with a pendant or terminal group capable of anchoring and / or compatibilizing materials, e.g., to anchor or secure one layer to another. Non-limiting examples of suitable ethylene-based compatibilizer include anhydride modified materials, alkoxysilane materials, etc. In examples, the ethylene-based compatibilizer comprises an anhydride modified material. The anhydride modified material is not particularly limited. In examples, the anhydride modified material is an anhydride modified ethylene copolymer. The ethylene co-polymer can comprise comonomer units derived from acrylic acid, alkyl acrylic acid, vinyl acetate, or an alpha-olefin. In examples, the ethylene copolymer is an anhydride modified ethylene acrylate copolymer. An example of a suitable ethylene acrylate copolymer is ethylene methyl acrylate (EMA). In examples, the ethylene copolymer is an anhydride modified ethylene vinyl acetate. In examples, the ethylene-based compatibilizer can comprise an anhydride-grafted copolymer of ethylene and higher olefins. Non-functionalized ethylene copolymers such as EMA or EVA may be used as the compatibilizer or substituted for the functionalized ethylene copolymers. In examples, the ethylene-based compatibilizer is one or more of ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), and ethylene butyl acrylate (EBA).

[0053] Non-limiting examples of suitable ethylene-based compatibilizer include commercially available materials under the trademark "Bynel" (Dupont Co.) and "Primacor" (Dow Chemical Co.). Non-limiting examples of suitable materials for the ethylene-based compatibilizer include, but are not limited to, anhyd ride-modified ethylene acrylate copolymer such as Bynel 2169, Bynel 2174, Bynel 21E787, Bynel 21E810, or Bynel 21E533 available from DuPont Co.

[0054] FIG. IB is a schematic of an exemplary a heat-shrinkable package 200 formed from the laminate film 100 of FIGs. 1A. As shown, when used in food packaging, outer surface layer 140 is designated as a food contact surface. In examples, outer surface layer 140 is configured for printing by any means common in the industry. In examples, outer surface layer 140 is configured for receiving a label, e.g., an adhesive label. In examples, heat-shrinkable package 200 is shown sealed at end 210.Attorney Docket No.: 045389-001055

[0055] Using an exemplary apparatus illustrated in FIG. 2, resins are extruded by a plurality of extruders "A." For simplicity, only one extruder A is illustrated in FIG. 2. The melted resins were introduced into an annular die "B" such that the layers have a laminate configuration from the outer side to the core side of the film, and each of the layers has a given thickness. In examples, annular die B provides a 5-layer extrudate from three extruders. A melted tubular body is discharged from the outlet of the annular die B into a water ring / tank "C" onto a pinch roller "D" to form a film. Next, the film-shaped tubular body is heated in an in-line oven, then into air ring "E" formed into a bubble-shaped tubular film by inflation. Then, the bubble-shaped tubular film is simultaneously biaxially stretched and annealed in annealing unit "F" Thereafter, the tubular film is taken up on pinch roller D for slitting "G" and winding "H."

[0056] In FIG. 3, a more detailed exemplary process is depicted, where solid polymer beads (not illustrated) are fed into a plurality of extruders 300. For simplicity, only one extruder 300 is illustrated in FIG. 3. The melt (optionally degassed) from each extruder 300 is introduced into annular multilayer die 301. In examples, three extruders 300 provide for a 5-layer extrudate exiting multilayer die 301.

[0057] The melt streams from extruders 300 are fed into and exit multilayer annular die 301 as discrete layers, resulting in annular multilayer extrudate 303. In examples, the number of extruders 300 corresponds is less than the discrete layers in multilayer annular extrudate 303. In examples, the extrudate from a single extruder 300 is split into two or more streams, with each stream being used to form a discrete layer of multilayer annular extrudate 303 (as shown in FIG. 1A).

[0058] In examples, as annular extrudate 303 exits annular die 301, and passes inside calibrator 305 positioned below annular die 301 to control the diameter of extrudate. In examples, calibrator 305 can be surrounded by vacuum chamber 307 connected to a source of vacuum (not shown). In examples, cold water sprayers 309 are provided inside vacuum chamber 307. In examples, the bottom edge of vacuum chamber 307 is provided with sealing ring 311.

[0059] In examples, collapse of annular extrudate 303 is prevented by maintaining a slight super-atmospheric pressure inside annular extrudate via centrally positioned pipe 313 passing through the center of annular die 301, and extending downward from annular dieAttorney Docket No.: 045389-001055301. Alternatively, or in addition to maintaining a slight positive pressure inside annular extrudate 303 (i.e., inside the "first bubble"), a slight vacuum, e.g. 10-30 millibars, is provided in internal region 315.

[0060] In examples, the diameter of annular extrudate 303 is closely controlled while the thermoplastic resins emitted from annular die 301 are quenched upon extrusion. In examples, the rate of extrusion of resin from annular die 301, in combination with control over the downward speed of annular extrudate 303 using control of the surface speed of nip rollers 317, and control of necking down of annular extrudate 303 as it exits annular die 301.

[0061] In examples, annular extrudate 303 moves downward into water bath 319, and is collapsed into lay-flat configuration by nip rollers 317 within water bath 319. The resulting lay-flat configuration then passes over idler rollers 323 and 325, and then through irradiation chamber 327 and around idler roller 329, and then through upper nip rollers 331. In examples, an E-beam in-line process of about 4-5 megarads (MRads) for a 60 gauge material is used.

[0062] In examples, immediately after passage thru upper nip rollers 331, extrudate 321 is re-inflated to a predetermined extruded diameter as it passes through one or more ovens 333 positioned around the entirety of annular extrudate 335. In examples, heaters 333 progressively heat inflated annular extrudate 335 to a softening point characteristic of the extrudate, after which the inflated, softened annular extrudate 337 passes through a set of supporting guide rollers 339. In examples, guide rollers 339 are configured to maintain inflated annular extrudate 335 and bubble 341 in a central position in the oven, so that annular extrudate 335 and bubble 341 can be heated evenly. After passing through guide rollers 339, extrudate 337 is blown into bi-axia lly oriented bubble 341.

[0063] In examples, the entirety of bubble 341 contains trapped air 343 between upper nip rollers 331 and lower nip rollers 345. In examples, lower nip rollers 345 have a surface speed higher than upper nip rollers 331, thereby stretching softened bubble 341 in the machine direction, while the greater diameter of oriented bubble 341 provides transverse orientation of bubble 341. In examples, annealing heaters 346 are provided along bioriented bubble 341.

[0064] In examples, lower nip rollers 345 collapse biaxial ly oriented bubble 341 into a lay-flat configuration 349 and is wound upon roll 367. Flat configuration 349 can beAttorney Docket No.: 045389-001055 dispensed in conventional food packing equipment for heat-shrinking, heat sealing operations.

[0065] As used here, ethylene a-olefin plastomers include terpolymers of ethylene and higher a-olefin comonomers (butene, hexene, octene). In examples, the ethylene a-olefin plastomers are prepared using the Ziegler-Natta heterogeneous catalyst systems or ethylene a- homogeneous metallocene single-site catalyst systems. In examples, ethylene a-olefin plastomers (POP) of about 0.902g / cm3density and melt index of about MF lg / 10 minutes were used. The ethylene a-olefin polyolefin plastomer polymer of the first surface layer and the second surface layer of the presently disclosed laminate can be the same or different.

[0066] Examples of ethylene a-olefin polyolefin plastomer polymers include Exxon EXACT® grades 3025, 3027, 3033, 3034, 4011; Dow ATTANE® grades 4001, 4003, Dow AFFINITY® grades PL 1840, PL 1880; Mitsui TAFMER® grades A-4085, A-4090, A-1085, Exxon Exxtra™ Seal Pop grades 2008, 7500, 17000, or blends. Other ethylene a-olefin polyolefin plastomer polymers can be used and / or blended together.

[0067] In examples, LLDPE of about 0.92g / cm3density and melt index of about MF lg / 10 minutes were used. In examples, LLDPE of 0.92g / cm3density and melt index of about MF lg / 10 minutes were used.

[0068] Examples of LLDPE include, but are not limited to, Nova Sclair® FP120 grades FP120-A, FP120-AS, FP120-C, FP120-CO2, FP120-CE02, FP120-CN02, FP120-D, or blends thereof. Other LLDPE can be used and / or blended together.

[0069] In examples, ethylene-vinyl-acetate-copolymer with a co-monomer content of between 5-15 weight percent vinyl acetate are used. In examples, ethylene-vinyl-acetate- copolymer with a melt index of about 1 g / 10 minutes to about 3 g / 10 minutes is used. In examples, ethylene-vinyl-acetate-copolymer with a density of about 0.93 g / cm3is used. Examples of ethylene-vinyl-acetate-copolymer include EVATANE® grades (Arkema), ATEVA® grades (Celanese), EVAX* grades (Dow), and the like.

[0070] In examples, ethylene methyl acrylate copolymer with a co-monomer content of between 15-25 weight percent methyl acrylate is used. In examples, ethylene methyl acrylate copolymer with a co-monomer content of about 21.5 weight percent is used. In examples, ethylene methyl acrylate copolymer with a melt index of about 1.0 g / 10 minutesAttorney Docket No.: 045389-001055 to about 3 g / 10 minutes is used. In examples, ethylene methyl acrylate copolymer with a melt index of about 2.0 g / 10 minutes is used. In examples, ethylene methyl acrylate copolymer with a density of about 0.943 g / cm3is used. Examples of ethylene methyl acrylate copolymer include, but are not limited to, Elvaloy™ AC grades (Dow), Exxtra™ Soft EMA grades (Exxon), EMAC® grades (Westlake), and the like.

[0071] In examples, FDA approved (for direct food contact) one or more processing aids, antioxidant additives, fillers, preservatives, anti-block agents, anti-slip agents, UV stabilizers, etc., are used. In examples, an anti-fog agent can be used in the inner layer composition of the laminate. In examples, the anti-fog agent may be at least 5 wt. %, at least 10 wt. %, at least 15 wt. %, at least 20 wt. %, at least 25 wt. %, or at least 30 wt. % of one or more inner layers of the laminate. In examples, the anti-fog agent may be 15-30 wt. % of the at least one inner layer of the laminate. In examples, the anti-fog agent may be up to 5% wt. % of the multilayer laminate composition. In examples, the anti-fog agent may be 0.5 wt. % and 5 wt. % of the multilayer laminate composition. In examples, an anti-fog agent with a density of about 0.93 g / cm3is used. Exemplary suitable anti-fog agents include anti-fog agents that are compatible with polyethylene / plastomer films and can include, but are not limited to, AF4953LL, AF5979PE, AF7380PE, BR7483PE, and BR7783DP available from Tosaf, Atmer™ 100, 1006, 1010, and 1440 NV available from Cargill, and Cesa™ Nofog Plus and Nofog 2101 available from Avient, or combinations thereof.

[0072] An "anti-fog agent" as used herein refers to an agent that modifies at least one surface of a film to reduce, minimize, or ameliorate the effects of moisture condensation on the film. One or more anti-fog agents may be dispersed or incorporated into the film before extruding the film. Exemplary anti-fog agents can include, but are not limited to, polyethers, polyhydric alcohols, esters of polyhydric aliphatic alcohols, polyethoxylated aromatic alcohols, non-ionic ethoxylates, and hydrophilic fatty acid esters.

[0073] Table 1 represents an exemplary core layer composition of the laminate, Table 2 represents an exemplary inner layer composition of the laminate. Table 3 represents an exemplary surface layer composition of the laminate, and Table 4 represents the exemplary laminate. Remainder is understood to be the weight percent required for totaling 100 weight percent when combined with all other components representing a layer or the laminate.Attorney Docket No.: 045389-001055

[0074] It is understood that the relative weight percentages of the plastomer polymer and LLDPE polymer described in the exemplary multilayer laminate composition of Table 4Attorney Docket No.: 045389-001055 comprising ethylene vinyl acetate as the ethylene-based compatibilizer can be reversed to provide cost savings provided that such a formulation maintains the functional performance as presently disclosed. In examples, the exemplary multilayer laminate composition of Table 4 comprising ethylene vinyl acetate as the ethylene-based compatibilizer can further include an anti-fog agent as disclosed herein.

[0075] Table 5 represents an exemplary core layer composition of a laminate comprising an ethylene-based compatibilizer. Table 6 represents the exemplary inner layer composition of the laminate comprising ethylene methacrylate copolymer. Table 7 represents the exemplary surface layer composition of the laminate. Table 8 represents exemplary weight percents of the total multilayer composition. The remainder, if any, is understood to be the weight percent required for totaling 100 weight percent when combined with all other components representing a layer of the laminate. The laminate compositions can be used as wraps or films for food packaging, e.g., wraps suitable for meat packaging, such as poultry and seafood.Table 5. Exemplary Core Layer CompositionTable 6. Exemplary Inner Layer CompositionAttorney Docket No.: 045389-001055Table 7. Exemplary Surface Layer CompositionTable 8. Exemplary Multilayer Laminate Composition

[0076] Table 9 represents an exemplary core layer composition of a laminate comprising ethylene methacrylate copolymer and an anti-fog agent. Table 10 represents an exemplary inner layer composition of the laminate comprising ethylene methacrylate copolymer. Table 11 represents the surface layer composition of the laminate. Table 12 represents weight percents of the total multilayer composition. The remainder, if any, is understood to be the weight percent required for totaling 100 weight percent when combined with all other components representing a layer of the laminate. The laminate compositions can be used as wraps or films for food packaging, e.g., wraps suitable for meat packaging, poultry, or seafood.Attorney Docket No.: 045389-001055Table 9. Exemplary Core Layer Composition

[0077] The introduction of ethylene-based compatibilizer to the laminate formulation in one or more inner and / or surface layers and core layer provided a wider processing window than current commercial products as demonstrated by performance benefits compared to commercial products. Performance benefits included a smoother tactile feel compared toAttorney Docket No.: 045389-001055Control (Cryovac™ film (Sealed Air)), which was described as tacky, reduced Heat Seal temperatures ranging from about 135 °C to about 177 °C (about 275 °F to about 351 °F) without burn through, compared to > 200 °C for Control, cross-seal and bottom seal and seal integrity was exceptionally good, and pressure tank test at standard threshold@ 10-12 PSI passed, with further testing up to 18 PSI, without leakage.

[0078] While certain embodiments of the present disclosure have been illustrated with reference to specific combinations of elements, various other combinations may also be provided without departing from the teachings of the present disclosure. Thus, the present disclosure should not be construed as being limited to the particular exemplary embodiments described herein and illustrated in the Figures, but may also encompass combinations of elements of the various illustrated embodiments and aspects thereof.

Claims

Attorney Docket No.: 045389-001055WE CLAIM:

1. A heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate, comprising(i) a core layer comprising: an ethylene a-olefin polyolefin plastomer polymer, a linear low density polyethylene (LLDPE), and optionally an ethylene-based compatibilizer;(ii) at least one surface layer comprising: an ethylene a-olefin polyolefin plastomer polymer, an ethylene-based compatibilizer; and(iii) at least one inner layer between at the least one surface layer and the core layer, the at least one inner layer comprising: an ethylene a-olefin polyolefin plastomer polymer, and an ethylene-based compatibilizer, and a linear low density polyethylene (LLDPE).

2. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of claim 1, excluding polyester, polyamide, polystyrene, and copolymers thereof.

3. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of claim 1 or 2, wherein the laminate is crosslinked.

4. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-3, wherein the laminate is crosslinked before orientation.

5. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-4, wherein the at least one inner layer is directly adjacent the core layer.

6. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-5, wherein the at least one inner layer is extrusion laminated to the core layer and the at least one surface layer is extrusion laminated to the at least one inner layer.Attorney Docket No.: 045389-0010557. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-6, wherein the at least one inner layer further comprises an anti-fog agent.

8. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of claim 7, wherein the at least one inner layer further comprises 10-30 percent by weight of the antifog agent.

9. The heat-shrinkable, heat sealable, bi-oriented multi-layer laminate of claim 7 or 8, wherein the anti-fog agent is up to 5 wt. % of the total film weight.

10. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-9, wherein the at least one surface layer further comprises a linear low density polyethylene (LLDPE).

11. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-10, wherein the weight percent of LLDPE is 50-75 wt. % of the total film weight.

12. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-11, wherein the weight percent of the ethylene a-olefin polyolefin plastomer (POP) is 15-35 wt. % of the total film weight.

13. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-12, wherein the LLDPE comprises at least 30 wt. % of the at least one inner layer.

14. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-13, wherein the LLDPE comprises 30-70 percent wt. % of the at least one inner layer.

15. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-14, wherein: the core layer comprises 65-85 percent by weight of the linear low density polyethylene, 5-25 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of the ethylene-based compatibilizer;Attorney Docket No.: 045389-001055 the at least one inner layer comprises 30-55 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; 5-20 percent by weight of the ethylene-based compatibilizer; and 10-30 percent by weight of the anti-fog agent; and the at least one surface layer comprises 50-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-20 percent by weight of the ethylene-based compatibilizer.

16. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-7, wherein: the core layer comprises 65-80 percent by weight of the linear low density polyethylene, 10-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer, and up to 10 percent by weight of the ethylene-based compatibilizer; the at least one inner layer comprises 50-70 percent by weight of the linear low density polyethylene, 15-30 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; 5-15 percent by weight of the ethylene-based compatibilizer; and the at least one surface layer comprises 40-70 percent by weight of the linear low density polyethylene, 15-35 percent by weight of the ethylene a-olefin polyolefin plastomer polymer; and 5-15 percent by weight of the ethylene-based compatibilizer.

17. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-7, wherein the weight percent of LLDPE is 10-14 wt. % of the total film weight.

18. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-7, wherein the weight percent of the ethylene a-olefin polyolefin plastomer (POP) is 75-85 wt. % of the total film weight.

19. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-7, wherein:(i) the core layer comprises:Attorney Docket No.: 045389-00105575-85 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, 10-20 percent by weight of a linear low density polyethylene (LLDPE), and 1-10 percent by weight of ethylene-based compatibilizer;(ii) the least one surface layer comprises:70-80 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, and 10-20 percent by weight of ethylene-based compatibilizer; and(iii) the at least one inner layer comprises: less than 70 percent by weight of an ethylene a-olefin polyolefin plastomer polymer, 10-20 percent by weight of ethylene-based compatibilizer, and 10-20 percent by weight of a linear low density polyethylene (LLDPE).

20. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-19, wherein a weight of the core layer is at least three times a combined weight of the at least one inner layer and the at least one surface layer.

21. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-20, wherein the ethylene-based compatibilizer is one or more of ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), ethylene ethyl acrylate (EEA), ethylene butyl acrylate (EBA), anhydride modified ethylene acrylate copolymer, or anhydride-grafted copolymer of ethylene and higher olefins.

22. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-21, wherein the ethylene-based compatibilizer is ethylene vinyl acetate (EVA).

23. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-22, wherein the ethylene-based compatibilizer is ethylene methyl acrylate (EMA).

24. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-23, comprising: a first outer layer;Attorney Docket No.: 045389-001055 a first inner layer adjacent the outer layer; a core layer adjacent the first inner layer; a second inner layer adjacent the core layer; and a second outer layer adjacent the second inner layer; where the weight of core layer is at least 60 wt. % of the total film weight.

25. The heat-shrinkable, heat sealable, bi-oriented, multi-layer laminate of any one of claims 1-24, configured to heat shrink at a contact surface temperature range between about 160 °C to about 200 °C (about 320 °F to about 392 °F).

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