WO2001094111A1

WO2001094111A1 - Thermoformable film structures useful for packaging food products

Info

Publication number: WO2001094111A1
Application number: PCT/US2001/018035
Authority: WO
Inventors: Jay D. Hodson; Kevin Douglass; Duane H. Buelow
Original assignee: Pechiney Emballage Flexible Europe
Priority date: 2000-06-08
Filing date: 2001-06-04
Publication date: 2001-12-13
Also published as: AR029936A1; PA8518901A1; AU2001265353A1

Abstract

Thermoplastic films having at least two layers wherein the first layer comprises a polymer or a blend of polymer selected from the group consisting of polypropylene, high density polyethylene, PVC, PET, polyester poly(acrylonitrile) or HIPS and the second layer is a sealant layer wherein said layer comprises a sealant polymer and a cheese release additive are disclosed. The film structures can be thermoformed into rigid structures of various shapes. The thermoplastic films are useful in the packaging of cheese.

Description

THERMOFORMABLE FILM STRUCTURES USEFUL FOR PACKAGING FOOD PRODUCTS

This invention relates to thermoplastic polymeric films useful in the packaging of food products, especially, cheese and other diary products. More specifically, the invention is in the field of polymeric thermoplastic films that are thermoformable i.e. , may be softened through the application of heat, distorted to a desired shape, and cooled.

Polymeric films are useful in the packaging field for the packaging of products, especially food products. Films used for the packaging of food, generally contain multiple layers in which each layer adds certain desired physical or chemical properties to the completed film. Food packaging methods utilizing polymeric films can be exemplified in many ways, i.e. , enveloping the product in a polymeric clear film or placing the product in a rigid structure which is formed from a polymeric thermoplastic film. It is the latter of these methods to which this invention is directed.

The use of thermoformable film structures to form rigid structures such as trays or tubs is known. It is also known that these rigid structures usually require a lidding component. The lidding component can be a flexible sheet material which is adhered to the structure to form a closing and sealing lid. The lidding component can also be a rigid plastic cap. The lidding component can also be a combination of the two. The use of formed, rigid structures and lidding, in general, is known and applicable to the packaging of food products. For examples, jellies, jams, dressing yogurt and pudding are commonly packaged in individual servings in formed trays with peelable sheet materials used for lids sealed to the trays. Larger trays and accompanying lids have been used in the packaging of complete servings of prepared foods. However, in the packaging of some food products such as a processed cheese loaf, the packaging is limited to a corrugated box in which the cheese loaf is placed. This type of packaging has the following disadvantages (a) lack of portion control, i.e. , smaller individual servings; (b) lack of reclosability; and (c) lack of resealability. Therefore, there is a need to develop a package for this type of product that will overcome the disadvantages of the old package and yet meet the processing and packaging requirements of the product.

The package for the cheese product must withstand relatively severe processing conditions either at the points where the package is being filled or sealed or at the point where the package and/or its contents is to be used. Such packaging typically encounters substantial heat at the point where the package is filled and sealed, and may be subjected to significant heat at the point where the package is used. At the point of packaging, the packaging may be subjected to, for example, hot-filled product at approximately 165 °F. The package must also provide protection to the contained food from the permeation of substances into the package from the outside environment. Substances which can have undesirable affects on the contained product are, for example, oxygen, moisture, contaminants and light. It is especially important to protect the packaged contents from oxygen, moisture and light, in addition to the typical containing and protecting functions of the package. The rigid package also serves as a cheese mold to shape the final product when cooled. The package also needs cheese release or the ability to allow easy removal of the cheese loaf by the consumer without significant residue and adhesion of the product to the container walls. Resins for providing these individually desired protective properties are known and are available, and are commonly used in packaging applications. For example, oxygen penetration can be successfully impeded through the use of vinyl alcohol polymers such as ethylene vinyl alcohol copolymer and vinylidene chloride copolymers. Moisture penetration may be prevented by use of certain polymers, for example, polyolefins.

Description of the Prior Art

Ramesh, et al., U.S. Patent No. 5,763,095 discloses a multilayer film having a combination of relatively low oxygen transmission and relatively high carbon dioxide transmission. The film includes at least one layer containing a nylon copolymer. Nan der Ploeg, et al., U.S. Patent No. 4,472,339 discloses a process of manufacturing a plastic cheese mold, comprising: providing a mold having a cavity defined in it, which cavity is shaped to define the exterior wall of the container, and which mold is further comprised of a mandrel, or the like, fitted into the cavity, wherein the mold defines an outer, inwardly facing wall of the cavity and the mandrel, or the like, defines an opposite, inner, outwardly facing wall, and the mold and the mandrel, or the like, being shaped to define a relatively thin walled opening between the outer and opposite inner walls thereof; applying a porous non-woven layer of polyolefin fibers to the inner wall of the mold; and filling the cavity by injection molding with a liquid mass of polyolefin material at an elevated temperature selected for the polyolefin material to heat seal to the fibers of the non-woven layer.

Lulham, et al., U.S. Patent No. 5,595,623 discloses a method of making a film comprising: blending from about 5% to about 95% by weight of ethylene vinyl acetate copolymer having from about 3% to about 18% by weight of vinyl acetate with from about 5 % to about 95 % by weight of ethylene/alpha-olefin copolymer having a density of less than about 0.915 g/cc; extruding said blend through a circular coextrusion die; immediately blowing the extrudate to a diameter appropriate for achieving the desired thickness for the final film; cooling the coextruded film; and collapsing the cooled film. Temple, U.S. Patent No. 4,977,931 discloses a packing material, generally in sheet form, made from a combination of a support sheet and a water-retentive material that is intimately connected to the support sheet. Moisture or exudate originating from a product enclosed by the packing material is absorbed and retained by the water-retentive material without affecting the physical strength of the support sheet or the packaged product. In a preferred embodiment, the support sheet is made of paper or a polymeric material, such as polyethylene, and the water retentive material is formed from poly aery lonitrile, or a polyacrylonitrile based co-polymer, treated with an alkaline aqueous solution of aliphatic or cycloaliphatic monofunctional or polyfunctional alcohols that have melting points greater than or equal to 110°C. The packaging material is ideal for the packaging of moisture sensitive foods, such as cheese.

It is an object of this invention to provide novel thermoplastic film structures, sheet materials and novel packages made from said thermoplastic film structures and said sheet materials.

The rigid structures which are molded from the thermoplastic film structures of the present invention are capable of withstanding hot-fill temperatures of about 165 °F. The rigid structures are also capable of protecting the package contents from penetration, moisture and light and in certain preferred embodiments from oxygen. It is a specific object of the invention to provide thermoplastic film structures having at least two layers wherein one of said layers contains a polymer and a cheese release additive.

It is another specific object of the invention to provide a novel thermoplastic film structure having an oxygen barrier resin core layer. It is another specific object of the invention to provide a rigid structure which is produced from the thermoplastic film structures of the present invention wherein said structure is capable of withstanding a hot-fill temperature of about 165 °F.

It is another specific object of the present invention to provide a package comprising a rigid structure which is made from the film structures of the present invention and a lidding component. Definition of Terms

Unless specifically set forth and defined or otherwise limited, the following terms as used herein have the following meanings.

Adhesive shall mean substances which bind/adhere; adhesives as used herein can generally be classified either as tie resins or laminating adhesives. Caliper shall mean the thickness of a film layer.

Cheese release additive shall mean GMS, GMO or other fatty acids or a blend of GMS, GMO or other fatty acids and a polyolefin such as poly ropylene). Core or core layer shall mean an interior layer of a multilayer film having an odd number of layers wherein the same number of layers is present on either side of the core layer.

Ethylene vinyl acetate copolymer (EVA) shall mean a copolymer formed from ethylene and vinyl acetate monomers wherein the ethylene derived units in the copolymer are present in major amounts and the vinyl acetate derived units in the copolymer are present in minor amounts.

Ethylene vinyl alcohol copolymer (ENOH) shall mean a copolymer formed by the hydrolysis of poly (vinyl acetate). GMO shall mean glycerol mono-oleate.

GMS shall mean glycerol mono-stearate.

HIPS shall mean high impact poly(styrene).

Interior or interior layer shall mean a layer of a multilayer film which is not a skin or surface layer of the film. Intermediate or intermediate layer shall mean an interior layer of a multilayer film which is positioned between a core layer and a surface layer of said film.

LDPE shall mean low density poly (ethylene).

LLDPE shall mean linear low density poly(ethylene).

Polyethylene shall mean families of resins obtained by substantially polymerizing the gas ethylene. By varying the comonomers, catalyst and methods of polymerization, properties such as density, melt index, crystallinity, degree of branching, molecular weight and molecular weight distribution can be regulated over wide ranges. Polyethylenes include low density polyethylenes (LDPE); medium density polyethylenes (MDPE); and high density polyethylenes (HDPE). Comonomers which are useful in the polyethylene resin family are alpha-olefins having from 4 to 20 carbons.

PET shall mean poly(ethylene) terephthalate.

Polymer or polymer resin include but are not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc., and blends and modifications thereof. Polymer or polymer resin shall also include all possible molecular configurations of the material. These structures include but are not limited to, isotactic, syndiotactic and random molecular configurations.

Polyolefins shall mean polymers of olefins such as, for example, ethylene, propylene, butenes, isoprenes and pentenes; including but not limited to homopolymers, copolymers, blends and modifications of said olefins. PVC shall mean poly(vinylchloride).

Re grind shall mean recycled material from the film structure; regrind shall also include in addition to the recycled material "virgin" material wherein said material is selected from any of the components of the film structure.

Surface or surface layer or skin or skin layer shall mean a layer of a multilayer film which comprises a surface thereof.

Thermoformable shall mean softened through the application of heat, distorted to a desired shape, and cooled. Tie resin or layer shall mean an adhesive comprised of thermoplastic polymer that has some affinity for materials it is meant to adhere to or bind together; typically tie resins are used in coextrusion or extrusion lamination and typically are polyolefin copolymers such as EVA, EAA or EM A, or polyolefins that are grafted with maleic anhydride (examples of grafted materials are Plexar^® from Equistar and Bynel^® from DuPont).

Summary of the Invention

The present invention provides a multiple layer thermoplastic film structure comprising at least two layers, a first layer comprising a polymer selected from the group consisting of polypropylene, high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS and second sealant layer wherein said sealant layer also contains a cheese release additive and wherein the sealant is selected from the group consisting of LLDPE, LDPE, ENA and other polyolefins. The present invention further provides a multiple layer thermoplastic fihn structure comprising five layers, a first layer comprising an oxygen barrier polymer, a second layer comprising an adhesive or tie layer wherein said second layer is disposed in contact with said first , layer, a third layer comprising an adhesive or tie polymer wherein said third layer is disposed in contact with said first layer and opposite said third layer, a fourth layer comprising a polymer selected from the group consisting of polypropylene, high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS wherein said fourth layer is disposed in contact with said second layer, and a fifth sealant layer wherein said sealant layer also contains a cheese release additive and wherein the sealant is selected from the group consisting of LLDPE, LDPE ENA and other polyolefins and wherein said five layer structure may optionally contain one or more regrind layers. The present invention also provides for a thermoformed rigid structure which is capable of withstanding a hot-filled temperature of about 165 °F. The thermoformed rigid structure is produced from a thermoplastic film structures of the present invention.

The present invention also provides a package comprising a thermoformed rigid structure which is produced from a thermoplastic multiple layer film structure and a lidding component. Said lidding component being a flexible sheet material, a rigid polymeric cap or a combination a sheet material and a rigid polymeric cap. Brief Description of the Drawings

Figure 1 depicts a two layer film structure of the present invention; Figure 2 depicts a five layer film structure of the present invention; Figure 2A depicts a seven layer film structure of the present invention;

Figure 3 depicts a rigid structure of the present invention; and Figure 4 depicts a package of the present invention. Detailed Description of the Invention

In its first embodiment, the thermoplastic films of the present invention is a two-layer structure comprising a first layer comprising a polymer or a blend of polymer wherein the polymer is selected from the group consisting of polypropylene, high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS and a second sealant layer wherein said sealant layer also contains a cheese release additive and wherein the sealant is selected from the group consisting of LLDPE, LDPE, ENA and other polyolefins. In the second sealant layer the cheese release additive is selected from the group consisting of GMS, GMO or other fatty acids and starch. The cheese release additive comprising from about 2% to 10% of the total second layer, preferably 5%. A preferred cheese release additive is GMS. A preferred sealant is LLDPE. A preferred LLDPE is Exxon 1001.29 from Exxon-Mobil, Bay Town, Texas. The rigid package serves as a cheese mold to shape the final product when cooled. The package also needs cheese release or the ability to allow easy removal of the cheese loaf by the consumer without significant residue and adhesion of the produce to the container walls. In the first layer a preferred polymer is polypropylene. A preferred polypropylene is Exxon PD-5132 from Exxon-Mobil, Bay Town, Texas. A preferred first layer contains 100% of the selected polymer; however, the first layer may also contain a blend of the polymers which have been recited above. A typical blend could be about 30% poly(propylene) to about 70% high density poly(ethylene). In its second embodiment, the thermoplastic films of the present invention is a five layer structure. The total film structure may have any thickness and preferably has thickness from 20 to 80 mils, most preferably from 40 to 50 mils.

The first layer is an oxygen barrier layer which contains ethylene vinyl alcohol copolymer ("ENOH") or polyvinylidene dichloride (PNdC). The first layer may have a thickness of between 2% to 5 % of the total film structure, preferably about 2.5% of the total film structure. A suitable ethylene vinyl alcohol copolymer for practice in the present invention is exemplified by Evalca LC-F101AZ from ENALCA of Lisle, Illinois. A suitable polyvinylidene dichloride for practice in the present invention is exemplified by Saran from Dow Chemical Co., Midland, Michigan. Ethylene vinyl alcohol copolymer is a preferred oxygen barrier polymer. Evalca LCF-101A2 is a most preferred ENOH from Evalca, Lisle, Illinois.

Disposed in contact with and on either side of the oxygen barrier layer are the tie or adhesive layers, layers 2 and 3. Each of layers 2 and 3 may have a thickness of from 2% to 5% of the total thickness of the film, preferably about 2.5%. Suitable adhesives or tie polymers for the practice of the invention are exemplified by maleic anhydride modified polyolefins wherein the polyolefins are selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene vinyl acetate copolymer or polypropylene. A preferred adhesive is maleic anhydride modified polypropylene. A most preferred adhesive Admer QF-500A from Mitsui Chemicals, Tokyo, Japan.

Layer 4 comprises a polymer selected from the group consisting of polypropylene, high density polyethylene, PNC, PET, poly (aery lonitrile) or HIPS. Layer 4 may comprises a single polymer selected from the group recited above or may compromise a blend of two or more of the polymers recited above. A typical blend could be about 30% polypropylene) to about 70% high density poly (ethylene). A preferred polymer for layer 4 is polypropylene. A preferred polypropylene is Exxon PD-5132 from Exxon-Mobil, Bay Town, Texas. Layer 4 may have a thickness of from 10 to 50% preferably 25% .

Layer 5 is a sealant layer comprising a sealant and a cheese release additive. Suitable sealant are selected from the group consisting of LLDPE, LDPE, ENA and other polyolefins. A preferred sealant is linear low density polyethylene. A preferred LLDPE is Exxon 1001.29 from Exxon-Mobil, Bay Town, Texas. The cheese release additive is selected from the group consisting of GMS, GMO or other fatty acids and starch. A preferred cheese release additive is GMS. The cheese release additive is present from about 2% to 10% of the sealant layer, preferably 5%. The cheese release additive allows for separation of the product from the polyolefin sealant.

The five layer thermoplastic film structure of the present invention may also contain one or more regrind layers. The regrind layer or layers comprises recycled trim from the processed film structure. The regrind layer may also contain in addition to recycled trim "virgin" material or non-processed material wherein said material may be any one of the components of the five layer structure. In a preferred embodiment of the present invention in which a regrind layer or layers is present, the regrind layer comprises about 80% recycled trim and 20% "virgin" material. The regrind layer or layers are positioned in the interior portion of the film structure. For example in the five layer film structure of the present invention the regrind layer or layers may be placed in contact with adhesive or tie layers.

In another embodiment, the present invention is a rigid structure which is made from the thermoplastic film structures of the present invention. In a preferred embodiment of the rigid structure, the structure is a tub having the following dimensions 4"x9'x2.5" and depicted in Figure 3. The rigid structure is made by a thermoformed process. The thermoformed process involves heating of the sheet, clamping the hot sheet to a flange on the mold or die and then using either vacuum or air pressure or both to form into the shape of the die and cool the finished product. While a particular rigid structure has been exemplified, it is to be understood that the rigid structure may have many shapes depending on the shape of the mold.

In the present invention the rigid structures which are formed from the thermoplastic film structures of the invention are capable of withstanding hot-filled temperature of about 165 °F. In still another embodiment, the present invention is a package comprising a rigid structure which is made from the thermoplastic fihn structures of the present invention and a lidding structure.

The rigid structures of the present invention have been described above. The lidding structure can be a sheet material, a rigid plastic cap or a combination of the two. A sheet material can be exemplified by a foil-based polyolefin film structure wherein the polyolefin is polyethylene. An example of a lidding structure is PET/adh/foil/adh/PEsealalnt. A rigid plastic cap can be exemplified by 20ml polypropylene rigid structure in a shape to effect a closure over the bottom rigid structure. The rigid lidding structure can be placed directly over the bottom rigid structure or can be placed over the sheet material which has been affixed to the bottom rigid structure.

Films of the present invention can be formed by any of the conventional processes for making multilayer films, including, extrusions, coextrusions, blown extrusion, cast extrusion, tubular water quenched extrusion, extrusion coatings, and the like, and combinations thereof. Coextrusion is presently preferred for forming a multilayer film structures of the present invention .

The total film structures of the present invention may have any thickness, and preferably has thickness of from 2 to 5 mils, most preferably 3 mils.

The following non-limiting examples are given by way of the illustration and are not intended to be considered a limitation on the invention.

EXAMPLE 1

By coextrusion a seven layer thermoplastic film structure was produced comprising a first layer of ethylene vinyl alcohol copolymer; a second and third tie layer wherein each tie layer comprises maleic anhydride modified polypropylenes and wherein each tie layer is adjacent said first layer; a fourth and fifth layer wherein each layer comprises regrind; and wherein each of said regrind layers are adjacent each of said tie layers, a sixth layer wherein said layer comprises polypropylene and wherein said sixth layer is adjacent one of the regrind layers and a seventh layer comprising linear low density polyethylene and GMS wherein said seventh layer is adjacent the other regrind layer. The film structure of Example 1 has the following specification:

EXAMPLE 2

By coextrusion, a two layer thermoplastic film structure is produced comprising a first layer of polypropylene and a second sealant layer comprising linear low density poly ethylene and a cheese release additive. EXAMPLE 3

By coextrusion, a five layer thermoplastic film structure is produced comprising a first layer of ethylene vinyl alcohol copolymer; a second and third tie layer wherein each tie layer comprises a maleic anhydride modified polypropylene and wherein each of said tie layer is adjacent said first layer; a fourth layer comprising polypropylene wherein said fourth layer is adjacent one of the tie layer; and a fifth layer comprising linear low density polyethylene and a cheese release additive wherein said fifth layer is adjacent the other tie layer.

EXAMPLE 4 By coextrusion, a five layer thermoplastic film structure is produced comprising a first layer of ethylene vinyl alcohol copolymer; a second and third tie layer wherein each tie layer comprises a maleic anhydride modified polypropylene and wherein each of said tie layer is adjacent said first layer; a fourth layer comprising high density polyethylene wherein said fourth layer is adjacent one of the tie layer; and a fifth layer comprising linear low density polyethylene and a cheese release additive wherein said fifth layer is adjacent the other tie layer.

EXAMPLE 5 By coextrusion, a five layer thermoplastic film structure is produced comprising a first layer of ethylene vinyl alcohol copolymer; a second and third tie layer wherein each tie layer comprises a maleic anhydride modified polypropylene and wherein each of said tie layer is adjacent said first layer; a fourth layer comprising polypropylene wherein said fourth layer is adjacent one of the tie layer; and a fifth layer comprising low density polyethylene and a cheese release additive wherein said fifth layer is adjacent the other tie layer. EXAMPLE 6

By coextrusion, a five layer thermoplastic film structure is produced comprising a first layer of ethylene vinyl alcohol copolymer; a second and third tie layer wherein each of said tie layer comprises a maleic anhydride modified polypropylene and wherein each tie layer is adjacent said first layer; a fourth layer comprising a blend of high density poly(ethylene) and polypropylene wherein said fourth layer is adjacent one of the tie layer; and a fifth layer comprising linear low density polyethylene and a cheese release additive wherein said fifth layer is adjacent the other tie layer. In Examples 2 to 6 a preferred (poly)propylene is Exxon PD-5132 Exxon¬

Mobil, Bay Town, Texas; a preferred linear low density poly (ethylene) is Exxon 1001.29 from Exxon-Mobil, Bay Town, Texas; a preferred ethylene vinyl alcohol copolymer is Evalca LC-F101AZ Evalca, Lisle, Illinois; a preferred tie adhesive is Admer QF-500A from Mitsui Chemicals, Tokyo, Japan; a preferred cheese release additive is GMS from manufacturer. Detailed Description of the Drawings

Figure 1 shows a multi-layer film (14) which comprises two layers first layer (20) comprising a polymer selected from the group consisting of polypropylene, high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS and a second sealant layer (22). Sealants which are suitable for practice in this invention have been discussed in detail under Detailed Description of the Invention. Sealant layer (22) also contains a cheese release additive.

Figure 2 shows a multilayer film (14) which comprises five layers, an oxygen barrier layer (24); a tie layer (26) and a second tie layer (28) where said tie layers are disposed in contact with and on either side of the oxygen barrier layer (24); a layer (20) comprising a polymer selected from the group consisting of polypropylene), high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS and wherein said layer (20) is disposed in contact with tie layer (26); and a layer (22) comprising a sealant polymer and a cheese additive wherein said layer (22) is disposed in contact with tie layer (28). Polymers which are suitable for use in the film structures described above have been discussed in detail under Detailed Description of the

Invention.

Figure 2 A shows a multilayer film (14) comprising seven layers, an oxygen barrier layer (24); a tie layer (26) and a second tie layer (28) wherein said tie layers are disposed in contact with and on either side of the oxygen barrier layer (24); a regrind layer (32)wherein said regrind layer is disposed in contact with tie layer (28); a regrind layer (30) wherein said regrind layer is disposed in contact with tie layer

(26); a layer (20) comprising a polymer selected from the group consisting of polyφropylene), high density polyethylene, PNC, PET, poly(acrylonitrile) or HIPS and wherein said layer (20) is disposed in contact with regrind layer (30); and a sealant (22) layer comprising a sealant and a cheese release additive wherein said sealant layer is disposed in contact with regrind layer (32). The components which are useful in the various layers described above have been discussed in detail under

"Detailed Description of the Invention." Figure 3 depicts a tub made from the thermoformable films of the present invention.

Figure 4 depicts a tub made from the thermoformable films of the present invention with a sheet material lidding component.

Claims

CLAIMSWe claim:

1. A thermoplastic film structure having at least two layers comprising:

(a) a first layer comprising a polymer or a blend of polymers selected from the group consisting of polyφropylene), high density poly (ethylene), poly(acrylonitrile), PNC, PET or HIPS; and

(b) a second sealant layer comprising a sealant polymer selected from the group consisting of linear low density poly(ethylene) low density poly(ethylene) or ethylene vinyl acetate copolymer and a cheese release additive.

2. The thermoplastic film of claim 1 wherein said first layer comprises polyφropylene).

3. The thermoplastic film of claim 1 wherein said first layer comprises high density poly (ethylene).

4. The thermoplastic film of claim 1 wherein said second layer comprises linear low density poly (ethylene) and a cheese release additive.

5. The thermoplastic film of claim 4 wherein the cheese release additive of said second layer is present from about 2% to 10%.

6. The thermoplastic film of claim 5 wherein the cheese release additive is present from about 5 % .

7. A rigid structure made from the thermoplastic film of claim 1.

8. A rigid structure made from the thermoplastic film of claim 2.

9. The rigid structure according to claim 7 in the form of a tub having dimensions of 4"x9"x2.5" .

10. The thermoplastic film of claim 1 further comprising one or more layers of regrind.

11. A thermoplastic film structure having five layers comprising a first layer comprising a polymer selected from ethylene vinyl alcohol copolymer or polyvinylidene dichloride; a second layer comprising a maleic anhydride modified poly(olefin) wherein said polyolefin is selected from the group consisting of high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene vinyl acetate copolymer or poly(propylene) and wherein said second layer is disposed in contact with said first layer; a third layer comprising a maleic anhydride modified poly(olefin) wherein said polyolefin is selected from the group consisting of high density polyethylene, low density polyethylene linear low density polyethylene, ethylene vinyl acetate copolymer of poly(propylene) and wherein said third layer is disposed in contact with said first layer and opposite said second layer; a fourth layer comprising a polymer selected from the group consisting of poly ropylene), high density poly (ethylene), PNC, PET; poly (aery lonitrile) or HIPS wherein said fourth layer is disposed in contact with said second layer; and a fifth layer comprising a polymer selected from the group consisting of LLDPE, LDPE or ENA wherein said fifth layer is disposed in contact with said third layer and wherein said fifth layer contains a cheese release additive.

12. The thermoplastic film structure according to claim 10 further comprising one or more regrind layers.

13. The thermoplastic film structure according to claim 11 wherein a regrind layer is disposed in contact with layer two and layer three.

14. A rigid structure made from the thermoplastic film of claim 10.

15. The rigid structure according to claim 13 in the form of a tub having dimensions of 4"x9"x2.5" .

16. The thermoplastic film structure according to claim 11 wherein the first layer comprises ethylene vinyl alcohol copolymer.

17. A thermoplastic film structure having five layers comprising a first layer comprising ethylene vinyl alcohol copolymer; a second layer comprising maleic anhydride modified poly ropylene) wherein said second layer is disposed in contact with said first layer; a third layer comprising maleic anhydride modified polyφropylene) wherein said third layer is disposed in contact with said first layer and opposite said second layer; a fourth layer comprising poly ropylene) wherein said fourth layer is disposed in contact with said second layer; and a fifth layer comprising linear low density poly(ethylene) and a cheese release additive wherein said fifth layer is disposed in contact with third layer.

18. The thermoplastic film structure according to claim 17 further comprising one or more regrind layers.

19. The thermoplastic structure according to claim 18 wherein a regrind layer is disposed in contact with layer two and layer three.

20. A rigid structure made from the thermoplastic film of claim 17.

21. The rigid structure according to claim 20 in the form of a tub having dimensions of 4"x9"x2.5".