Barrier packaging webs having metallized non-oriented film

(54) Title: IMPROVEMENT INTRODUCED IN BARRIER BRACES / STRIPS FOR PACKAGING WITH AN UNIENTED METALLIZED FILM (30) Unionist Priority: 10/31/2007 us 11 / 932,031 (73) Owner (s): Bemis Company, Inc (72 ) Inventor (s): chris scott mussell, curtis RANDOLPH BARR, SAM EDWARD WUEST, STEVEN JAMES DENNIS (57) Summary: The present invention provides flexible packaging straps comprising a non-oriented metallized sealant film characterized by a drying module of less than 120,000 psi and an elongation to break greater than 150%, where the non-oriented metallized sealant film comprises (1) a base layer thermoplastic of a material selected from a group consisting of ethylene / vinyl alcohol copolymer, ethylene / acrylic acid copolymer, ethylene / norbornene copolymer, polyamide and any mixtures thereof; (2) a metallic covering deposited on the base layer and having an optical density of 1.0 to 3.0; and (3) a heat sealing layer. The packaging straps of the present invention each exhibit an oxygen transmission rate between 0 and 10.0 cm3 / 100 in2 / 24 hours at 73 ° F. (0 to 155 cm3 / m2 / 24 hours at 23 ° C.) And 0% relative humidity and a water vapor transmission rate between 0 to 0.1 g / 100pol2 / 24 hours at 100 ° F. (0 to 1.55 g / m2 / 24 hours at 38 ° C.) And 90% relative humidity. The sealing films are formed using a blown coextrusion method.

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1/43 ”10004143-1

IMPROVEMENT INTRODUCED IN BARRIER BRACES / STRIPS FOR PACKAGING WITH A METALIZED FILM NOT ORIENTED

Technical field

This invention is related to the field of packaging.

In particular, the present invention relates to flexible straps / strips for packaging suitable for use in packaging applications and, more particularly, straps / strips for packaging food and non-food products sensitive to oxygen and moisture.

History of the invention

Plastic materials such as polymeric films have been widely used for packaging various food and non-food products.

In order to ensure the proper preservation of products packaged in such polymeric films, it is necessary to provide films with barriers against the transmission of air, moisture, harmful odors, etc.

Unmodified polymeric films, however, typically lack sufficient gas moisture barrier characteristics necessary for the appropriate packaging requirements.

For example, polyolefin films are particularly preferred in the manufacture of packaging films due to their low cost and easy fabrication.

Such films, however, typically allow the transmission of oxygen and water vapor from the outer portion of the film to the inner portion of the packaging made from the film.

2/43

As will be recognized by those skilled in the art, the transmission of oxygen and water vapor through food packaging materials promote the deterioration of food within said packaging.

The use of a metallized film to improve the barrier properties of flexible packaging films is known in the art.

Typically, such barrier films are formed by depositing a thin layer of a metal, most typically aluminum, on a thermoplastic substrate oriented prior to the deposition of the metal.

A requirement of these polymer substrates or films is that they are uniaxially oriented, ie, pulled in one direction or, more commonly, biaxially oriented, ie, pulled in both longitudinal and transversal directions before being metallized.

For example, United States patent number 5,283,118 by Murakami et al., The disclosure of which is hereby incorporated by reference, reveals oriented metallized films having water vapor transmission rate (VWTR) values ​​between 0.011 to 0, 10 g / 100in²/ 24 hours and oxygen transmission values ​​(O₂TR) between 1 and 30 cm³/ 100in²/24 hours.

Metallization is achieved by vacuum deposition of aluminum vapor and aluminum alloys on a surface of a biaxially oriented propylene copolymer or homopolymer substrate.

United States patent number 5,698,317 by Kurokawa et al., The disclosure of which is hereby incorporated by

3/43 reference, teaches that the oxygen transmission rate between 0.4 and 1.14 cm³/ 100in²/ 24 hours for the films can be obtained by means of vacuum deposition of metal vapor on the surface of the biaxially oriented multilayer film of the packaging straps / strips having a polypropylene-based composition.

United States patent number 5,827,615 by Touhsaent et al., The disclosure of which is hereby incorporated by reference, discloses a biaxially oriented film substrate of ethylene / vinyl alcohol (EVOH) surface having an aluminum coating applied by means of conventional vacuum deposition.

The resulting films have excellent barrier properties, ie, WVTR values ​​below 0.1 g / 100in²/ 24 hours and OTR values ​​less than 0.1cm³/ 100in²/24 hours.

A need exists for a metallized packaging material having sufficient gas and moisture barrier properties, formed from a non-oriented substrate.

Brief description of the invention

It is an object of the present invention to provide a flexible packaging strap / strip having a non-oriented metallized sealing film coextruded with an oxygen barrier and an improved water vapor barrier and / or sealing properties.

It is also an object of the present invention to provide a flexible strip / strip for packaging having a coextruded, non-oriented metallized sealing film with improved barrier properties. be simple and inexpensive to manufacture.

These and other objects are achieved in the present invention which provides a flexible packaging strap / strip

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a) comprising a coextruded, non-oriented, metallized, sealant film characterized by a drying module of less than 120,000 psi and an elongation to break greater than 150%, where the non-oriented metallization sealant film comprises (1) a thermoplastic base layer of a material selected from a group consisting of ethylene / vinyl alcohol copolymer, ethylene / acrylic acid copolymer, ethylene / norbornene copolymer, polyamide and any mixtures thereof; (2) a metallic covering deposited on the base layer and having an optical density of 1.0 to 3.0; and (3) a heat sealing layer.

b) Where the packing belt / strip has an oxygen transmission rate between 0 and 10.0 cm³/ 100in²/ 24 hours at 73 ° F (0 to 155 cm³/ m²/ 24 hours at 23 ° C) and 0% relative humidity and a water vapor transmission rate between 0 to 0.1 g / 100in²/ 24 hours at 100 ° F (0 to 1.55 g / m²/ 24 hours at 38 ° C) and 90% relative humidity.

Preferably, the non-oriented film is coextruded using the blow coextrusion method.

Within an embodiment of the present invention, the base layer is a copolymer of ethylene / vinyl alcohol and the strap / packaging strip has an oxygen transmission rate between 0 and 0.5 cm³/ 100in²/ 24 hours at 73 ° F (0 to 7.75 cm³/ m²/ 24 hours at 23 ° C).

In another embodiment of the present invention, the base layer is an ethylene / acrylic acid copolymer and the belt / strip has an oxygen transmission rate between 0 and 0.5 cm³/ 100in²/ 24 hours at 73 ° F (0 to 7.75 cm³/ m²/ 24 hours at 23 ° C).

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In yet another embodiment of the present invention, the base layer is a polyamide and the strap / packaging strip has an oxygen transmission rate between 0 and 0.5 cm³/ 100in²/ 24 hours at 73 ° F (0 to 7.75 cm³/ m²/ 24 hours at 23 ° C).

Even in yet another embodiment of the present invention, the base layer is an ethylene / norbornene copolymer and the belt / strip has an oxygen transmission rate between 0 and 5.0 cm³/ 100in²/ 24 hours at 73 ° F (0 to 77.5 cm³/ m²/ 24 hours at 23 ° C).

In some embodiments, the packaging strap / strip has a heat seal resistance of 2,000 g / inch (2,000 g / 2.54 cm) at 280 ° F (138 ° C).

The flexible belt / strip of the present invention may further include a second layer of oriented or non-oriented film.

The oriented films of the second layer can comprise any thermoplastic material and, preferably, include a thermoplastic film having at least one layer of polyethylene terephthalate, polypropylene, polyamide, polylactic acid or any mixtures thereof.

Non-oriented films can include any thermoplastic or non-thermoplastic material such as, for example, paper, cardboard, cardboard, regenerated cellulose and the like.

Within an embodiment the present invention is a multilayer packaging strip / strip having a oriented film adjacent the metal layer of the non-oriented metallized sealant film.

Within another embodiment, the present invention is a multilayer packaging strap / strip having an unoriented film adjacent to the metal layer of the metallized sealant film

6/43 not oriented.

In yet another embodiment, the present invention is a two-layer packaging strip / strip having an oriented film adjacent to the meta-layer of the non-oriented metallized sealant film.

Brief description of the drawings

FIGURE 1. is an illustration of a cross-sectional view of an incorporation of a metallized sealant film not oriented in accordance with the present invention.

FIGURE 2. is an illustration of a cross-sectional view of an incorporation of a two-layer packaging strap / strip in accordance with the present invention.

FIGURE 3. is an illustration of a cross-sectional view of another embodiment of a two-layer packaging strap / strip in accordance with the present invention.

FIGURE 4. is an illustration of yet another cross-sectional view of an incorporation of a two-layer packaging strap / strip in accordance with the present invention.

Definitions

As used herein, the terms "lamination" and "laminate" refer to the process and the resulting product, made from the joint joining of two or more continuous film surfaces to form a multi-film structure.

Lamination can be achieved by joining films with an adhesive using adhesive lamination or with a bonding layer using cover extrusion.

Lamination is described in the United States patent of

America number 5,374,459, by Munpower et al., Which is here

7/43 incorporated by reference.

The term "thermoplastic" refers to a material that softens when exposed to heat and that substantially returns to an undoed condition when cooled to room temperature.

In some embodiments of the present invention, the first strap / strip or the second strap / strip and preferably at least the second strap / strip of the strap / packaging strip comprises a thermoplastic material.

Alternatively, both the first and second straps / strips of the strap / packaging strip include a thermoplastic material.

The term "polymer" includes, but is not limited to, homopolymers and copolymers, such as, for example, copolymers, terpolymers and etc., block, grafted, random and alternate and any of their mixtures and modifications.

In addition, unless otherwise specifically limited, the term "polymer" must include all possible configurational isomers of the material.

These configurations include, but are not limited to, isotactic, syndiotactic and atactic symmetries.

As used here, the term "copolymer" refers to polymers formed from the copolymerization reaction of at least two different monomers.

For example, the phrase “ethylene / norbornene copolymer 25 can include the product of the ethylene and norbornene copolymerization reaction.

The term "copolymer" refers to a copolymer in which each monomer can copolymerize by weight or percentage

8/43 molar higher than other monomer or monomers.

However, the first listed monomer preferably polymerizes at a higher weight percentage than the second listed monomer.

The terminology employing a 7 ”with respect to the chemical identity of a copolymer (eg, ethylene / norbornene copolymer) identifies the comonomers to which they are copolymerized to produce the copolymer.

As used here, the term "extrusion" refers to the process of continuous molding of shapes by forcing a melted plastic material through a tool, followed by chemical cooling or hardening.

As used herein, the terms "coextrusion" and coextruded "refer to a process by which the resin coming out of two or more extruders is gently brought together within a feed block to form a multilayer flow that is fed into a tool to produce a layered extrudate.

Coextrusion can be used in blown and molded film coextrusion methods.

As used herein, the phrase “blow film coextrusion refers to the coextrusion process that includes an apparatus having a heated multi-slit circular tool through which the film layers are forced and molded into a multilayer cylindrical bubble.

The bubble can be hardened eg, via cold water bath, solid surface and / or air and then finally coiapsada and formed in a multilayer film.

Films produced using the blown film process

9/43 are known in the art and have been described, for example, in The Encyclopedia of Chemical Technology, Kirk-Othmer, 3^The ed., John Wiley &amp; Sons, New York, 1981, Vol. 16 pp 416-417 and Vol 18, pp 191192, the disclosures of which are hereby incorporated by reference.

Typically, resins and additives forming one or more layers of film are introduced into an extruder where the resins are plastically melted by means of heat and then transferred to an extrusion (or coextrusion) tool for molding in a bubble or tube.

If desired, resins can be mixed or mechanically mixed using well-known methods using commercially available equipment including concrete mixers, agitators or mixers and well-known additives such as processing aids, sliding agents, anti-blocking agents, pigments and any mixtures thereof can be incorporated into the resin by the pre-extrusion mixture.

Extruder and tool temperatures will generally depend on the particular resin (s) containing the mixtures being processed and desired temperature ranges for commercially available resins are generally known in the art or are provided in technical bulletins made available by resin manufacturers.

Processing temperatures may vary depending on the processing parameters used.

After molding the bubble is cooled, collapsed and wrapped around a reel! for further processing.

The terms "treated surface" and "surface treatment" both refer to any technique that changes the energy of the

10/43 surface (or surface tension) of a film layer and may include techniques such as, but not limited to, corona, flame and plasma treatment, οζδοηίο, ultra high frequency electrical discharge, laser or UV bombardment, chemical primer and the like.

The phrase “corona treatment” refers in general to the process where an electrical discharge generated by a high voltage electric field passes through the polymer substrate.

It is believed that the electrical discharge or "corona" can ionize the oxygen molecules around the substrate which then interact chemically with the atoms of the substrate surface thereby modifying the energy of the polymer substrate surface.

As used herein, the phrase “non-oriented multilayer film refers to a multilayer film structure that is substantially free of post-formation guidance.

It is known to those skilled in the art that the post-extrusion orientation will significantly affect the tensile properties of a film.

Stress properties can include, for example, but are not limited to, stress resistance to pressure, resistance to stress at break (or ultimate stress resistance), stress modulus (or Young modulus) and percentage of elongation at pressure and it breaks.

The phrase “secant module” refers to an approximation of the elastic module or Young module of a sample of plastic film.

The secant modulus is defined as the peak of a line from the origin of a curve (zero effort) to a specific stress point of the stress-stress curve.

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Procedures for measuring the drying module of a plastic film are defined in ASTM D 882, Standard Test Method for Tension Properties of Thin Plastic Sheets, which are hereby incorporated by reference.

For the purposes of the present invention, the drying module is measured in an effort of 1% and 2%.

The phrase “elongation to break” refers to the extension, ie, elongation or stretching produced by a tensile force at the moment of breaking a plastic film sample.

The procedures for measuring the elongation to break of a plastic film are defined in the ASTM D 882 standard, Test Method Standard for Tension Properties of Thin Plastic Sheets, which are hereby incorporated by reference.

As used herein, the phrase “ethylene / norbornene copolymer refers to a class of polymeric materials based on cyclic olefin monomers and ethane.

Ethylene / norbornene copolymers are commercially known as "COC" cyclic olefin copolymers, with one or more different cyclic olefin units randomly or alternately aggregated to the ethylene polymer column.

In general, COCs exhibit a high glass transition temperature (greater than 50 ° C), optical clarity, low heat shrinkage, low moisture absorption and low birefringence.

These materials can be produced through a number of polymerization techniques which include chain polymerization of cyclic monomers such as 8,9,10 trinorborn-2-ene (norbornene) from 1,2,3,4,4a, 5 , 8,8a-octahydro-1,4: 5,812 / 43 dimethanonaphthalene (tetracyclododecene) with ethane; open ring metathesis of several cyclic monomers followed by hydrogenation.

As used herein, the phrase “ethylene / vinyl alcohol copolymer” and the term “EVOH” both refer to a polymerized ethyl alcohol.

Ethylene / vinyl alcohol copolymers include saponified (or hydrolyzed) ethylene / vinyl acrylate copolymers and refer to a vinyl alcohol copolymer having an ethylene comonomer prepared by, for example, hydrolysis of vinyl acrylate copolymers or by means of chemical reactions with vinyl alcohol.

The degree of hydrolysis is preferably at least 50% and most preferably at least 85%.

Preferably the ethylene / vinyl alcohol copolymers 15 comprise approximately 28-48 mole% ethylene, more preferably approximately 32-44 mole% ethylene and even more preferably approximately 38-44 mole% ethylene.

As used herein, the term "polyamide" refers to 20 homopolymers or copolymers having an amide bond between units of monomers which can be formed by any method known to those skilled in the art.

In general, polyamides can include materials characterized as being crystalline, semi-crystalline and amorphous.

The phrase "amorphous polyamide" refers to polyamides or nylon with the absence of a regular three-dimensional arrangement of molecules or subunits of molecules extending over distances which are large in relation to dimensions

Atomic 13/43.

However, regularity of the structure exists on a local scale.

See “Amorphous Polymers”, in Encyclopedia of Polymer Science and Engineering, 2^The Ed. Pp. 789-842 (J. Wiley &amp; Sons, Inc. 1985), which is incorporated herein by reference.

In particular, an amorphous polyamide is a material generally recognized by anyone skilled in the art of calorimetry differential scanning (DSC) as having an unmeasurable melting point (less than 0.5 cal / gr) or having no melting heat. as measured by the DSC in accordance with that measured in accordance with test method ASTM 3417-83, which is hereby incorporated by reference.

In contrast, crystalline and semi-crystalline polyamides can be identified as having at least one melting point or heat of fusion as measured by the calorimetry differential scan.

Usable polyamide homopolymers include nylon 6 (polycaprolactam), nylon 11 (polyundecanolactam), nylon 12 (polyilaurillactam) and the like.

Other usable polyamide homopolymers also include nylon 4.2 (polytetramethylene ethylenediamide), nylon 4.6 (polytetramethylene adipamide), nylon 6.6 (polyhexamethylene adipamide), nylon 6.9 (polyhexamethylene nonanodamide), nylon 6,10. ), nylon 6.12 (polyhexamethylene dodecanediamide), nylon 7.7 (polyheptamethylene pimelamide), nylon 8.8 (polyoctamethylene suberamide), nylon 9.9 (polyamethylene azelamide), nylon 10.9 (polyamethylene azide) nylon 12.12 (polydodecamethylene dodecanediamide), and the like.

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Usable polyamide copolymers include the nylon 6.6 / 6 copolymer (polyhexamethylene adipamide / caprolactam copolymer), nylon 6.2 / 6.2 copolymer (ethylene diamine / hexamethylene ethylamine 6, copolymer 6, nylon 6 / copolymer) 9/6 (polyhexamethylene adipamide / hexamethylene azelamide / copolymer caprolactam) as well as other nylon, which are not particularly outlined in this description.

Examples of even more suitable polyamides include nylon 4, 1, nylon 6, l, nylon copolymer 6.6 / 61, nylon copolymer 6.6 / 6T, nylon MXD6 (poly-m-xylylene adipamide), copolymer of 6T / 6I nylon, 6 / MXDT / l nylon copolymer, MXDI nylon, adipamide poly-p-xylylene, polyhexamethylene terephthalamide and the like.

Commercially available polyamides include resins sold under the Ultramid® brand, particularly 6 / 6.6 crystalline copolyamide identified as Ultramid® C33 01 having a melting point of 195 to 197 ° C and a density of 1.12 g / cm³ which is sold by BASF Aktiengesellschaft, Ludwigshafen, Germany.

As used herein, the term "polyolefin" refers to homopolymers and copolymers, including eg, bipolymers, terpolymers, etc., having a methylene bond between monomer units, which can be formed using any methods known to those skilled in the art .

Suitable examples of polyolefins include polyethylene (PE), such as low density polyethylene (LDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE);

polyethylenes comprising ethylene copolymers with one or more alpha-olefins (α-olefins) such as butene-1, hexene-1, octene-1 or

5/43 similar as a comonomer, such as linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE), ultra low density polyethylene (ULDPE), ethylene / propylene copolymers, polypropylene, propylene / copolymer / ethylene, polyisoprene, polybutylene, polybutene, poly-3-methylbutene-1, poly-4-methylpentene-1, ionomers and the like.

Examples of available polyethylenes include, for example, HDPE resins such as those sold under the brand Alathon®, particularly Alathon® M6020 having a density of 0.960 g / cm³ and a melt index of 2.0 g / 10min, which can be obtained from Lyondell Chemical Company of Houston, Texas, United States of America; and LDPE resins such as those sold under the Equistar Petrothene® brand, particularly Equistar Petrothene® NA 216000 having a density of 0.923 g / cm³ and a melt index of 3.7 g / 10 min, which can be obtained from Equistar Chemical Company of Houston, Texas, United States of America.

As used herein, the phrase “metallocene-catalyzed polyethylene” here identified as “m-PE”, “m-VLDPE”, “m-MDPE” and the like, refer to any polypropylene formed through the copolymerization reaction with metallocene catalysis which include strained geometry catalysts, ie, monocyclopentadienyl transition metal complexes taught in United States patent number 5,026,798, by Canich, which is hereby incorporated by reference.

Metallocene-catalyzed polyethylenes can be characterized by one or more methods known to those skilled in the art such as molecular weight distribution (M_w/ M_n) composition of the width distribution index (CDBI), band

16/43 narrow melting point and singular melting point behavior.

The molecular weight distribution (M_w/ M_n) also known as “polydispersion”, can be determined by gel permeation chromatography (GPC), where M_w is defined as the average molecular weight and M_n is defined as the average number of the molecular weight.

The determination of the molecular weight of polymers and copolymers can be measured in accordance with the standards of ASTM D-3593-80, which are hereby incorporated by reference.

Metallocene-catalyzed polyethylenes suitable for use in the present invention can be homogeneous catalyzed copolymers of ethylene and an alpha-olefin which may have an M_w/ M_nless than 2.7; more preferably from 1.9 to 2.5; and even more preferably from approximately 1.9 to 2.3.

An alpha-olefin 3-20 carbon atoms hanging; preferably, 3-12 pending carbon atoms; and more preferably 3-6 pendant carbon atoms.

The composition of the width distribution index (CDBI) of homogeneous catalyzed copolymers of ethylene and an alphaolefin will generally be greater than approximately 70%.

This is contrasted with heterogeneous catalyzed copolymers of ethylene and an alpha-olefin which may have a width of distribution index of generally less than 55%.

The (CDBI) composition of the width distribution index is defined by the percentage of weight of the copolymer molecules having the content of a comonomer within 50% (ie, more or less 50%) of the average total molar content of

7/43 comonomer.

The (CDBI) composition of the width distribution index can be determined by the temperature rise fractionation elution (TREF) technique as described by Wild, et al., In the Journal of Polymer Science, Poly. Phys. Ed., Vol. 20, p. 441 (1982) and United States patent number 4,798,081, both of which are incorporated herein in their entirety, by reference.

Examples of metallocene-catalyzed polyethylene (m-PE) include metallocene-catalyzed (m-MDPE) medium density polyethylene such as those having a density of 0.934 g / cm³, a melting index of 0.9 g / 10min and a melting point of 124 ° C and sold by Total Petrochemicals USA, Inc., of Houston, Texas, United States of America.

As used herein, the terms "polylactic acid" and "polylactide" are used interchangeably to refer to homopolymers or copolymers having an ester bond between monomer units and can be represented by the general formula [-OCH (R) C (O) -]_n where R = CH₃.

Polylactic acid can be manufactured by the polymerization of lactic acid, which is mostly produced by fermenting corn carbohydrate.

Polylactic acid can also be produced by polymerizing lactide which is obtained by condensing two molecules of lactic acid.

Polylactic acid has a glass transition temperature ranging from 50-80 ° C, while the melting temperature varies from 130180 ° C.

Polylactic acid is known to those skilled in the art

18/43 and is fully disclosed in United States Patent Numbers 5,698,322; 5,142,023; 5,760,144; 5,593,788; 5,807,973; and 5,010,145, of which the full disclosure is hereby incorporated by reference.

Examples of commercially available polylactic acid are sold under the NatureWorks® PLA Polymer brand in grades 4031-D, 4032-D and 4041-D from Cargill Dow LLC, Minneapolis, Minnesota, United States of America.

As used herein, the term "modified anhydride" refers to any form of anhydride functionality, such as maleic acid anhydride, fumaric acid, etc., either copolymerized with a monomer containing anhydride or with a different second monomer grafted onto a polymer or copolymer or mixed with one or more polymers and is inclusive of derivatives of such functionalities, such as acids, esters and metal salts derived therefrom.

In accordance with the present invention, examples of suitable modified anhydride materials include, but are not limited to, a modified ethylene / vinyl acetate anhydride copolymer (mod-EVA) and modified anhydride polyolefins, preferably a modified anhydride polyethylene copolymer (modified -PE) having 0.05-1% by weight of maleic anhydride and 9999.95% by weight of polyolefin relative to the total weight of said modified anhydride polyolefin.

Those skilled in the art will recognize that the modified anhydride materials can serve as a suitable adhesive or bonding material in the preparation of coextruded packaging films or straps / strips.

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An example of a commercially available modified polyethylene anhydride (mod-PE) copolymer may include resins sold under the Bynel® brand, particularly Bynel® 41E712 which has a melting index of 1.5 g / 10min, a melting point 125 ° C and can be obtained from El from Pont de Nemours and Company, Wilmington, Dlaware, United States of America and those sold under the Plexar® brand, particularly Plexar® PX3308 having a melting index of 4.0 g / 10min, a melting point of 127 ° C and a density of 0.939 g / cm3 which is available from Equistar Chemicals LP of Houston, Texas, United States of America.

As used here, the phrase “regenerated cellulose” refers to a film produced from wood pulp using the viscose process. Regenerated cellulose can also be referred to as cellophane.

As used herein, the phrase “metallic coating” (which when applied forms the metallic layer) refers to a coating that can be applied to one or both surfaces of a film by any known method such as dispersion, deposition to vacuum or electrodeposition (all of which fall within the definition of film “metallization” and involve some act or method of “depositing” a layer of continuous metal, oxide or metal alloy on the surface of a polymer substrate).

The metal used can vary, although aluminum, zinc, gold, silver or appropriate alloys thereof are preferred, with aluminum or aluminum-containing alloys being particularly preferred.

As will be recognized by those skilled in the art, while the metallic covering predominantly consists of a

20/43 identified metal (such as aluminum), amounts of additives may be present to improve the various physical and optical properties of the deposited metal layer.

On some occasions, pure aluminum (or the metal of choice) may be used.

Other additives can be used in smaller quantities such that aluminum (or the metal of choice) is the largest component.

Vacuum deposition is a preferred method of metallization in terms of processing and cost.

Preferred values ​​of average thicknesses of the metallic covering layers are in the range of approximately 1.0 to 100 nanometers, with the preferred average thickness being in the range of approximately 3 to 25 nanometers. (1 micron is equal to 10 '⁷meters and 1 nanometer is equal to 10 '⁸ meters).

Regardless, the metal cover preferably has a thickness less than that of the polymer substrate on which it is deposited, preferably substantially less than said substrate.

In contrast, typical foils used in packaging film applications are 4.3 to 150 microns thick, as noted in “Foil, Aluminum in The Wiley Encyciopedia of Packaging Techmology, 2^The Ed., By the Foil Division of the Aluminum Association, Inc., pp. 458-463, which is incorporated herein by reference.

For a layer of aluminum cover, the key conditions are optical density (target deposition) of approximately 0.75 to 4, preferably 1.0-3.0.

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As used herein, the phrase “sealing film” refers to the portion of the packaging strap / strip surface (ie, formed from a single layer or multiple layers) which is capable of forming a melt bond to a second surface portion of a film or packaging strap / strip.

A sealing film is capable of melting together by means of indirect or conventional heating which generates sufficient heat on at least one contact surface of the film to guide the surface of the adjoining film and form a bonding interface between them without loss of film integrity.

Those skilled in the art will appreciate that the bonding interface between contiguous inner layers preferably has sufficient physical strength to withstand the packaging process and subsequent handling, including, for example, stresses resulting from the stretching or shrinkage that occurs with the presence of a body present in the package using a sealing film.

Advantageously, the coupling interface is preferably sufficiently thermally stable to prevent leakage of liquid or liquid gas into the packaging when exposed to temperature above or below ambient temperature, such as during packaging, storage, handling, transportation, display or processing operations. food.

Heat seals can be designed to correspond to different expected conditions of use and various heat-seeding formulations are known in the art and can be employed with the present disclosure.

For use in cooked food in the packaging,

22/43 heat seals must withstand high temperatures up to approximately 160-180 ° F (71-82 ° C), or higher, for example, 212 ° F (100 ° C), for long periods of time, such as 4 to 12 hours in environments that can vary from humidified air heated by water vapor to submersion in hot water.

Preferably the sealing layer is heat sealable to itself, but it can be sealable to other objects, films or layers such as a tray when using a cover film or to an outer layer when using a back seal or in certain embodiments of over-wrapped trays.

Also, in certain embodiments, the sealing layer is also a contact layer with the food.

In other embodiments, the sealing layer can be adapted to provide a detachable bonding interface between the film surfaces without losing sufficient physical strength.

Methods for forming a peelable bonding interface in packaging films using a sealing layer or in combination with other layers are known in the art and have been described, for example, in United States patent number RE37,171 by Busch et al. And in the published United States patent application number 2006/0269707 by Berbert, both of which are incorporated herein by reference.

In yet another embodiment, the sealing films can be further adapted to provide a detachable and resealable bonding interface.

Known examples of detachable and re-sealable sealants and film layers that include such a structure are described in published patent applications from the United States of America

23/43 numbers 2006/0172131 by Haedt et al. And 2007/0082161 by Cruz et al., Which are hereby incorporated by reference.

Those skilled in the art will recognize that a packaging strip / strip can be described in terms of its “peel strength which refers to the force required to separate at least a portion of the interface between two adjacent film surfaces joined together after the film has been sealed to a target substrate.

One method for determining peel strength is the ASTM F-904 test method entitled “Standard Test Method for Comparing Bond Strength or Adhesion of Similar Layer of Packaging Straps / Strips Made from Flexible Materials” published by ASTM International, West Conshohocken, Pennsylvania, United States of America, which is hereby incorporated by reference.

Although specific embodiments of the present invention are now described with reference to the drawings, it should be understood that such embodiments are a means of example only and merely illustrative of nothing more than a small number among the various specific possible embodiments which may represent applications of principles of present invention.

Detailed Description

The present invention is directed to flexible packaging straps / strips having a metallized, non-oriented coextruded seal film .

One method of distinguishing between an oriented and non-oriented belt / strip is to measure the relative tension properties before and after orientation.

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For example, the United States patent application number 2005/0287359 by Breese, which is hereby incorporated by reference, demonstrates the influence of the posformation orientation on the tension properties, for example, of a 6,000 mm monolayer film. high density polyethylene.

In particular, Breese teaches that with the increase in the orientation of the film (in the machine direction), the modulus increases and the percentage of elongation until the break decreases (in the machine direction) relative to samples of non-oriented films.

The sealing films of the present invention are non-oriented and have stress resistance properties which do not reflect post-formation orientation.

Preferably, the sealing films of the present invention exhibit a drying modulus less than 120,000 psi and an elongation to break greater than 150%.

In contrast, oriented films have a drying module greater than 120,000 psi and an elongation to break less than 150%.

For example, biaxially oriented polyamide (OPA) films such as those marketed under the Honeywell Capran® brand, particularly Honeywell Capran® Emblem ™ 1000 have a 400,000 psi drying module at 564,000 psi in the machine direction (MD) and 385,000 psi at 537,000 psi in the transverse direction (TD) and an elongation to break of 65% to 90% in the machine direction (MD) and 55% to 90% in the transverse direction (TD).

Biaxially oriented polyethylene terephthalate (ÕPET) films such as those marketed under the Mylar® brand by Teijin Dupont Films Japan Limited, Tokyo, Japan have a module

25/43 reported 550,000 psi and an elongation to break of 110% in the machine direction (MD) and 80% in the transverse direction (TD).

Biaxially oriented polypropylene (OPP) films such as those available from ExxonMobil Chemical Company have a reported module of 343,000 psi in the machine direction (MD) and 687,000 psi in the transverse direction (TD).

FIGURE 1 shows a partial diagram in perpendicular section of an incorporation of a non-oriented metallized coextruded seal film 10 in accordance with the present invention.

Film 10 is shown comprising at least one thermoplastic base layer 11, a metallic cover 12 deposited on the surface of the base layer 11 and a heat sealing layer.

The base layer 11 can comprise any synthetic or natural thermoplastic material, preferably polyolefins such as polyethylene; polypropylene; polybutylene; polyethylene copolymers which include, but are not limited to, ethylene / a-olefin copolymers, ethylene / vinyl alcohol copolymers (EVOH), ethylene / norbornene copolymers (COC), ethylene / vinyl acetate (EVA) and copolymers of ethylene / acrylic acid (EAA); polyamides, in particular amorphous polyamides; polyesters such as polyethylene terephthalate (PET), polyethylene isophthalate and polyethylene naphthalate; polycarbonates; ionomers and any mixtures thereof.

Examples of ethylene / acrylic acid (EAA) copolymers include the Dow Primacor® resin family, eg, Dow Primacor® 1430 grade having a reported density of 0.938 g / cm³, a melting flow of 5g / 10min, a melting point of 96 ° C and

26/43 available from The Dow Chemical Company, Midland, Michigan, USA.

Within a more preferred embodiment, the base layer 11 may comprise ethylene / vinyl alcohol (EVOH) copolymers, ethylene / norbornene (COC) copolymers, amorphous polyamides and any mixtures thereof.

Examples of available ethylene / vinyl alcohol (EVOH) copolymers suitable for use in the present invention include, but are not limited to, the SOARNOL® resin family, eg, SOARNOL® ET3803 graduation having a reported total density of 0.64-0, 74 g / cm³, a relative density of 1.13-1.22 g / cm³, a melting point of 164-188 ° C, an ethylene content of 38 mole% and available from The Nippon Synthetic Chemical Industry Company, Ltd. (Nippon Gohsei), Osaka, Japan.

Preferable examples of ethylene / norbornene copolymers suitable for use in the present invention include, but are not limited to, those commercially available and marketed under the APEL ™ trademark by Mitsui Chemicals America, Inc. Rye Brook, New York, United States of America; ARTON ™ by JSR Corporation (formerly Japan Synthetic Rubber, Ltd.), Chiba, Japan; and TOPAS® by TOPAS Advanced Polymers GmbH, Frankfurt-HÒchst, Germany.

A more preferable example from the TOPAS® family of resins includes TOPAS® 8007 which has a glass transition temperature of 136 ° C, a density of 1.02 g / cm³ and a water absorption of 0.01% at 23 ° C and 100% relative humidity.

Preferred examples of available amorphous polyamides suitable for use in the present invention include, but are not limited to

27/43 are limited to resins sold under the DuPont ™ Selar® brand by El de Pont de Nemours and Company, Wilmington, DE, United States of America.

An example of a more preferable polyamide includes 5 DuPont ™ Selar®PA 3426 which is a 6I / 6T nylon copolymer having a density of 1.19 g / cm³ and a glass transition temperature of 125 ° C.

Preferably the base layer 11 has a total thickness between 0.05 to 10 mils.

The metal cover 12 can be deposited on one or more surfaces of the base layer 11 by any conventional method known to those skilled in the art of metal deposition. The metal cover 12 can comprise any metal, metal oxide or metal alloy and is preferably an aluminum or aluminum alloy.

Preferably a metal vapor deposition technique is used to apply a layer of aluminum or aluminum alloy to a surface of the base layer 11.

Preferably, the metallic layer 12 has a thickness between 1.0 to 100 nanometers.

As shown in the drawings, the sealing layer 13 is positioned adjacent to the base layer 11 and can comprise any desired sealing material.

Preferably, the sealing layer 13 comprises a single polyolefin, for example, polyethylene, ionomer, polyester such as polyethylene terephthalate, or any mixtures thereof.

In a preferred embodiment, layer 13 comprises a polyethylene or polyethylene copolymer and more preferably,

28/43 comprises low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene catalyzed by metallocene (m-VLDPE), linear low density polyethylene catalyzed by metallocene (m-LLDPE ), an ethylene / vinyl acetate copolymer or any mixtures thereof.

Examples of a low density polyethylene include those supplied by The Dow Chemical Company, Midland, Michigan, United States of America, particularly, Dow Polyethylene 608A which has a density of 0.923 g / cm³, a melting index of 2.60 g / 10min and a melting point of 113 ° C.

Non-limiting examples of commercially available LLDPE suitable for the present invention include those sold under the brand name Dowlex®, in particular Dowlex® 2045G which has a density of 0.920 g / cm³, a melting index of 1.0 g / 10min, a melting point of 122 ° C and can be obtained from The Dow Chemical Company of Midland, Michigan United States of America; and those marketed by ExxonMobil Chemical Company, eg, ExxonMobil ™ LLDPE LL1001 having a density of 0.918 g / cm³, a melting index of 1.0 g / 10min and a melting point of 120 ° C.

M-LLDPE resins for use in the present invention include, but are not limited to, for example, those sold under the Exact ™ brand, particularly Exact ™ 3139 which is an ethylene α-olefin copolymer having a density of 0.900 g / cm³, a melting index of 7.5 g / 10min and a melting point of 95 ° C.

Suitable m-VLDPE resins include, for example, those sold under the brand name Exceed ™, in particular Exceed ™ 1012CA which is an ethylene α-olefin copolymer having a

29/43 density of 0.912 g / cm³, a melting index of 1.0 g / 10min and a melting point of 116 ° C.

Examples of m-LLDPE and m-VLDPE can each be obtained from ExxonMobii Chemical Company of Houston,

Texas, United States of America.

Non-limiting examples of suitable commercially available ethylene / vinyl acetate copolymers include the DuPont ™ Elvax® resin family, particularly DuPont ™ Elvax® 3169Z which has a density of 0.95 g / cm³, a melting index of 1.5 g / 10min, a melting point of 89 ° C, a vinyl acetate content of 18% per mole and is sold by El de Pont de Nemours and Company of Wilmington, DE, United States United States of America.

It is also contemplated that the sealing film 10 may comprise any number of additional film layers, including, for example, but not limited to oxygen and moisture barrier layers, coarse layers and adhesive layers.

Within another embodiment, the sealing film 10 further comprises a second sealing layer (not shown) which is in contact with the heat sealing layer 13 and is positioned between the heat sealing layer 13 and the base layer 11.

Preferably, the second sealing layer (not shown) comprises one or more antioxidants.

Suitable antioxidants within the present invention include, for example, Vitamin E, citric acid, ascorbic acid, ascorbyl pamitate, butylated phenolic antioxidant, tert-butyl hydroquinone (TBHQ) and propyl gallate (PG).

Preferably, the antioxidants used are those

30/43 butylated phenolic antioxidants including, for example, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).

Those skilled in the art recognize that antioxidants, particularly volatile antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) can migrate out of the film during storage, reducing the amount of antioxidant remaining in the packaging film over time where the packaging material is actually used to pack and store items, including, but not limited to food products.

Heat-sealing layer 13 is believed to control the migration of antioxidants through the second sealing layer and heat-sealing layer 13 to the surface of the sealing film 10, thus allowing the sealing film 10 to retain a high percentage of the amount original antioxidant.

In FIGURE 2, another embodiment of the packaging strap / strip in accordance with the present invention is illustrated.

The packaging strip / strip 100 comprises a non-oriented metallized coextruded sealing film 10 (as described above in FIGURE 1, ie, comprising a thermoplastic base layer 11, a metallic cover 12 and a heat sealing layer 13) and a oriented film 20.

As shown, the oriented film 20 is positioned adjacent to the surface of the metallic covering layer and opposite to the base layer 11 and may or may not be in contact with the metallic covering 12.

The oriented film 20 can comprise any thermoplastic material oriented as desired, and preferably includes a

31/43 oriented polyethylene terephthalate, oriented polypropylene or oriented polyamide.

It is noted that several combinations of additional layers and materials can be used in the formation of the oriented film 20.

FIGURE 3 shows another embodiment of the present invention.

As demonstrated, the belt / strip 200 comprises a non-oriented metallized coextruded sealing film 10 (comprising a thermoplastic base layer 11, a metallic covering 12 and a heat sealing layer 13), a oriented film 20 and an adhesive layer 21.

Preferably, the oriented film 20 is a biaxially oriented polyethylene terephthalate (OPET) film.

Adhesive layer 21 serves to affix film 20 to film 10. 15 Within an embodiment, adhesive 21 is a two-part polyurethane adhesive.

Non-limiting examples of OPET films include those sold under the Skyrol® brand, particularly Skyrol® SP65 48 gauge produced by SKC Co., Ltd., Seoul, South Korea.

FIGURE 4 illustrates yet another embodiment of the present invention.

The belt / strip 300 comprises a non-oriented metallized coextruded sealant film 10 (comprising a thermoplastic base layer 11, a metallic cover 12 and a heat seal layer 13), a oriented film 20, a first intermediate layer 31 and a second layer intermediate 32.

As shown, layer 31 is positioned between oriented film 20 and layer 32.

32/43

In one embodiment, oriented film 20 is a biaxially oriented polyethylene terephthalate (OPET) film, layer 31 is low density polyethylene (LDPE) and layer 32 is an ethylene / acrylic acid (EAA) copolymer.

Layer 32 can serve to fix both film 20 and layer 31 to film 10.

In the practice of this invention it may be desirable to treat the outer surface of either film 20 or film 10 before lamination.

Example 1

A base layer of 100.00% by weight of ethylene / vinyl alcohol copolymer (EVOH) was coextruded to a thickness of 0.125 thousand together with an adhesive (bonding) layer of 0.125 thousand of 100.00% of the weight of polyethylene of anhydridomodified linear low density (mod-LLDPE) and a 1.0 mil thick heat seal (sealant) layer comprising 61.20% by weight of a linear low density polyethylene (LLDPE), 33.50% by weight of a linear metallocene-catalyzed low density polyethylene (m-LLDPE) and 5.30% by weight of processing additives.

The three-layer film was coextruded using a blowing coextrusion method.

The resulting non-oriented coextruded film had a total thickness of approximately 1.25 mils, was tested for tension properties and then wound onto a coil.

The coil was then metallized by depositing aluminum vapor on the outer surface of the base layer to an optical density of 2.2.

The non-oriented metallized coextruded film had the

33/43 following structure: metal / EVOH / mod-LLDPE / LLDPE + m-LLDPE.

Example 2

A base layer of 100.00% by weight of ethylene / acrylic acid (EAA) copolymer was coextruded to a thickness of 0.26 mil along with a 0.14 mil layer comprising 56.10% by weight of density polyethylene low (LDPE), 25.00% by weight of linear low density polyethylene (LLDPE), 18.00% by weight of a concentrated linear low density polyethylene and 0.90% by weight of processing additives, a 0.10 mil thick bonding layer of 100.00% by weight of anhydride-modified linear low density polyethylene (mod-LLDPE), a 0.25 mil thick layer of 100.00% by weight of ethylene / vinyl alcohol copolymer (EVOH), a 0.10 mil thick joining layer of 100.00% by weight of anhydride-modified linear low density polyethylene (mod-LLDPE), a 0.2 mil layer thick comprising 56.10% by weight of a linear low density polyethylene (LLDPE), 25.00% by weight of linear low density polyethylene (LLDPE), 18.00% by weight of a concentrated linear low density polyethylene and 0.90% by weight of processing additives, and a sealing layer by heat (sealant) of 0.20 mil thick, 50.00% of the weight of a metallocene-catalyzed linear low density polyethylene (m-LLDPE), 42.20% of the weight of low density polyethylene (LDPE) and 7 , 80% by weight of a mixture of linear low density polyethylene and additive.

The resulting non-oriented coextruded film had a total thickness of approximately 1.25 mils, was tested for tension properties and then wound onto a coil.

34/43

The coil was then metallized by depositing aluminum vapor on the outer surface of the base layer to an optical density of 2.2.

The non-oriented metallized coextruded film had the following structure: metal / EAA / LDPE + LLDPE / mod-LLDPE / EVOH / mod-LLDPE / LDPE + LLDPE / m-LLDPE + LDPE.

Example 3

A base layer of 90.00% by weight of ethylene / norbornene copolymer (COC) and 10.00% by weight of a linear low density polyethylene (LLDPE) was coextruded to a thickness of 0.188 thousand together with a layer (thick) ) of 0.500 mil thick and 100.00% by weight of linear low density polyethylene catalyzed by metallocene (m-LLDPE), a layer of 0.188 thousand thick, 90.00% by weight of ethylene / norbornene copolymer (COC) and 10.00% by weight of a linear low density polyethylene (LLDPE), a layer of 0.188 thousand thick comprising 50 , 00% by weight of a very low density polyethylene catalyzed by metallocene (m-VLDPE), 27.00% by weight of an ethylene / vinyl acetate (EVA) copolymer having an acetate content of 18% per mole, 20.00% by weight of a mixture of 90:10 polyethylene (PE) and butylated hydroxytoluene (BHT) and 3.00% by weight of processing additives, and a second sealing layer (heat sealing layer) of 0.188 mil thickness of 60.00% of the weight of a very low density polyethylene catalyzed by metallocene (m-VLDPE), 34.00% of the weight of an ethylene / vinyl acetate (EVA) copolymer having an acetate content of 18% by mole and 6.00% by weight of a mixture of processing additives.

35/43

The five-layer film was coextruded using a blowing coextrusion method.

The resulting non-oriented coextruded film had a total thickness of approximately 1.25 mils, was tested for tension properties and then wound onto a coil.

The coil was then metallized by depositing aluminum vapor on the outer surface of the base layer to a target optical density of 2.0.

The non-oriented metallized coextruded film had the following structure: metal / COC + LLDPE / m-MDPE / COC + LLDPE / m-VLDPE + EVA + (PE + BHT) / m-VLDPE + EVA.

Example 4

A base layer of 90.00% by weight of ethylene / norbornene copolymer (COC) and 10.00% by weight of a linear low density polyethylene (LLDPE) was coextruded to a thickness of 0.188 thousand together with an adhesive layer ( of 0.188 thousand thickness comprising 85.00% of the weight of linear low density polyethylene (LLDPE), and 15.00% of the weight of linear low density polyethylene anhydride-modified (mod-LLDPE), a layer of 0.125 thousand thick of 100.00% by weight of copolyamide gradation 6 / 6.6 crystalline (c-PA), an adhesive (bonding) layer of 0.188 thousand in thickness of 85.00% by weight of polyethylene linear low density (LLDPE), and 15.00% by weight of anhydride-modified linear low density polyethylene (modLLDPE), a 0.188 mil thick layer comprising 98.00% of the weight of high density polyethylene (HDPE) and 2.00% by weight of polymer additives (antioxidants, stabilizers, etc.), a first sealing layer of 0.188 thousand thickness of 50.00% of the

36/43 weight of a very low density polyethylene catalyzed by metallocene (m-VLDPE), 27.00% by weight of an ethylene / vinyl acetate (EVA) copolymer having an acetate content of 18% per mole, 20 , 00% by weight of a mixture of 90:10 polyethylene (PE) and butylated hydroxytoluene (BHT) and 3.00% by weight of processing additives, and a second sealing layer (heat sealing layer) of 0.188 thousand thickness, 60.00% by weight of a very low density polyethylene catalyzed by metallocene (m-VLDPE), 34.00% by weight of a copolymer of ethylene / vinyl acetate (EVA) having an acetate content of 18% by mole and 6.00% by weight of a mixture of processing additives.

The seven-layer film was coextruded using a blowing coextrusion method.

The resulting non-oriented coextruded film had a total thickness of approximately 1.25 mils, was tested for tension properties and then wound onto a coil.

The coil was then metallized by depositing aluminum vapor on the outer surface of the base layer to a target optical density of 2.0.

The non-oriented metallized coextruded film had the following structure: metal / COC + LLDPE / LLDPE + mod-LLDPE / cPA / LLDPE + mod-LLDPE / HDPE / m-VLDPE + EVA + (PE + BHT) / mVLDPE + EVA.

The stress properties of the non-metallized films of

Examples 1 to 4 were measured in an Instron stress test.

The stress values ​​were determined in both machine (MD) and transverse (TD) directions.

The secant modulus at 1% and 2% and elongation to break

37/43 have been substantially tested in accordance with ASTM D 822.

A 2 inch initial footprint separation was used for this measurement.

The films were initially pulled at a rate of 0.5 inches / minutes; then at 4% effort, the speed changed to a rate of 20 inches / minute and pulled until the film broke.

The results are reported in Table 1 Table 1

Comparison of Voltage Properties

<td>MD 1% secant module (psi)</td><td>Example 1 74,733</td><td>Example 2 97,867</td><td>Example 3 97,188</td><td>Example 4 77.273</td>

<td>TD 2% secant module (psi)</td><td> 70.331</td><td> 103.445</td><td> 95.611</td><td> 88.181</td>

<td>MD 1% secant module (psi)</td><td> 62.976</td><td> 83.036</td><td> 85.646</td><td> 68.853</td>

<td>TD 2% secant module (psi)</td><td> 63.429</td><td> 85.088</td><td> 82.912</td><td> 75.464</td>

<td>MD elongation (%)</td><td> 185</td><td> 197</td><td> 175</td><td> 244</td>

<td>TD elongation (%)</td><td> 346</td><td> 360</td><td> 255</td><td> 313</td>

Example 5

A non-oriented metallized coextruded sealant film as described in Example 1 was laminated to a biaxially oriented polyethylene terephthalate film of 48 gauge by an adhesive lamination method.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET 48 gauge / adhesive / metal / EVOH / mod-LLDPE / LLDPE + m-LLDPE.

Example 6

A non-oriented metallized coextruded seal film, as described in Example 1, was laminated to an anchor film covered by 48-gauge biaxially oriented polyethylene terephthalate corona by an extrusion lamination method.

The two-layer flexible packaging strap / strip

The resulting 38/43 had the following structure: OPET gauge 48 / LDPE / EAA / metal / EVOH / mod-LLDPE / LLDPE + m-LLDPE.

Example 7

A process similar to that of Example 5 was repeated except that the metallized non-oriented metallized sealing film, as described in Example 2, was laminated to a biaxially oriented polyethylene terephthalate film of 48 gauge.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET 48 gauge / adhesive / metal / EAA / LDPE + LLDPE / mod-LLDPE / EVOH / mod-LLDPE / LDPE + LLDPE / m-LLDPE + LDPE.

Example 8

A process similar to that of Example 6 was repeated except that the metallized non-oriented metallized sealing film, as described in Example 2, was laminated to a biaxially oriented polyethylene terephthalate film of 48 gauge.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET gauge 48 / LDPE / EAA / metal / EAA / LDPE + LLDPE / mod-LLDPE / EVOH / mod-LLDPE / LDPE + LLDPE / m-LLDPE + LDPE.

Example 9

A process similar to that of Example 5 was repeated except that the metallized non-oriented metallized sealing film, as described in Example 3, was laminated to a biaxially oriented polyethylene terephthalate film of 48 gauge.

The resulting two-layer flexible clutch strap / strip had the following structure: OPET 48 gauge / adhesive / metal / COC + LLDPE / m-MDPE / COC + LLDPE / m-VLDPE + EVA + (PE +

I

39/43

BHT) / m-VLDPE + EVA.

Example 10

A process similar to that of Example 5 was repeated except that the metallized non-oriented metallized film, as described in Example 4, was laminated to a biaxially oriented polyethylene terephthalate film of 48 gauge.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET 48 gauge / adhesive / metal / COC + LLDPE / LLDPE + mod-LLDPE / c-PA / LLDPE + mod-LLDPE /

HDPE / m-VLDPE + EVA + (PE + BHT) / m-VLDPE + EVA.

Example 11

A process similar to that of Example 5 was repeated except that the metallized non-oriented metallized seal film, as described in Example 4, was laminated to a oriented polypropylene film.

The resulting two-layer flexible packaging strap / strip had the following structure: OPP / adhesive / metal / COC + LLDPE / LLDPE + mod-LLDPE / c-PA / LLDPE + mod-LLDPE / HDPE / m-VLDPE + EVA + (PE + BHT) / m-VLDPE + EVA.

Comparative Example 1

A process similar to that of Example 5 was repeated except that a 28 micron thick metallized oriented polypropylene sealing film was laminated to a biaxially oriented 48 gauge polyethylene terephthalate film.

The metallized oriented seal film was an OPP film identified as Metallyte® X-28 U BW-ES and obtained from ExxonMobil Chemical of Houston, Texas, United States of America.

The two-layer flexible packaging strap / strip

The resulting 40/43 had the following structure: OPET gauge 48 / adhesive / OPP metallic sealant 28 microns thick.

Comparative Example 2

A process similar to that of Example 5 was repeated except that a 40 micron oriented metallized polypropylene sealant film was laminated to a biaxially oriented 48-gauge polyethylene terephthalate film.

The metallized oriented sealing film was an OPP film identified as Metallyte® X-408 UBW-ES and obtained from ExxonMobil

Chemical from Houston, Texas, United States of America.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET 48 gauge / adhesive / OPP metallic sealant 40 microns thick.

Comparative Example 3

A process similar to that of Example 5 was repeated except that the 140 micron metallized oriented polypropylene sealing film was laminated to a biaxially oriented 48 gauge polyethylene terephthalate film.

The metallized oriented seal film was an OPP film identified as Treofan® QCM ™ and obtained from Treofan Group, Raunheim, Germany.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET 48 gauge / adhesive / OPP metallic sealant 140 microns thick.

Comparative Example 4

A process similar to that of Example 6 was repeated except that the 28 micron-thick metallized oriented polypropylene sealing film was laminated to a polyethylene terephthalate film

41/43 biaxially oriented with 48 gauge.

The metallized oriented seal film was an OPP film identified as Metallyte® X-28 UBW-ES and obtained from ExxonMobil Chemical of Houston, Texas, United States of America.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET gauge 48 / LDPE / EAA / OPP metallic sealant 28 microns thick.

Comparative Example 5

A process similar to that of Example 6 was repeated except that the 40 micron-oriented metallized polypropylene sealing film was laminated to a biaxially oriented 48-gauge polyethylene terephthalate film.

The metallized oriented sealing film was an OPP film identified as Metallyte® X-40 UBW-ES and obtained from ExxonMobil Chemical of Houston, Texas, United States of America.

The resulting two-layer flexible packaging strap / strip had the following structure: OPET gauge 48 / LDPE / EAA / OPP metallic sealant 40 microns thick.

The oxygen transmission rate (O₂TR) and water vapor transmission (WVTR) of Examples 5 to 11 and Comparative Examples 1 to 5 were measured.

The oxygen transmission rate was determined using Mocon Oxtran® 2/20 and 2/21 Oxygen Permeability Test Models substantially in accordance with ASTM D 3985, which is hereby incorporated by reference.

The oxygen transmission rate is reported in cm³/ 100 inches²/ 24 hours (cm³/ 645.16cm²/24 hours).

The rate of water vapor transmission was determined

42/43 using the Mocon Water Vapor Transmission Test

Permatran W® 3/31 substantially in accordance with ASTM F 1249, which is hereby incorporated by reference.

The rate of water vapor transmission is reported at 5 g / 100 inches²/ 24 hours (g / 645.16cm²/24 hours).

The results of said examples (“Ex”) and comparative examples (“CEx”) are shown in Table 2.

Table 2

Comparison of Barrier Properties

Thickness of

<td>Ex.5</td><td>samples (thousand) / (thousand) 1.80 / 1.80</td>

<td>Ex.6</td><td> 2,50/2,40</td>

<td>Ex.7</td><td> 1,70/1,70</td>

<td>Ex.8</td><td> 2,30/2,30</td>

<td>Ex.9</td><td> 1,68</td>

<td>Exx.10</td><td> 1,98</td>

<td>Ex.11</td><td> 2,04</td>

<td>CEx.1</td><td> 1,60/1,60</td>

<td>CEx.2</td><td> 2,00/2,00</td>

<td>CEx.3</td><td> 1,90/1,90</td>

<td>CEx.4</td><td> 2,10/2,20</td>

<td>CEx.5</td><td> 2,30/2,40</td>

O₂TR at 0% relative humidity and 23 ° C

<td> 0,00110</td><td> 0,02920</td>

<td> 0,00822</td><td> 0,00605</td>

<td> 0,11000</td><td> 0,10000</td>

<td> 0,23000</td><td> 0,23000</td>

<td> 0,80000</td><td></td>

<td> 0,32000</td><td></td>

<td> 0,36000</td><td></td>

<td> 0,07160</td><td> 0,02130</td>

<td> 0,04000</td><td> 0,08200</td>

<td> 0,20000</td><td> 0,18000</td>

<td> 0,23830</td><td> 0,21290</td>

<td> 0,15000</td><td> 0,21000</td>

VWTR at 90% relative humidity and 38 ° C

<td> 0,10810</td><td> 0,11950</td>

<td> 0,00980</td><td> 0,01170</td>

<td> 0,02100</td><td> 0,01300</td>

<td> 0,05800</td><td> 0,02900</td>

<td> 0,01100</td><td></td>

<td> 0,01940</td><td></td>

<td> 0,01840</td><td></td>

<td> 0,02990</td><td> 0,02490</td>

<td> 0,02000</td><td> 0,01200</td>

<td> 0,00900</td><td> 0,00890</td>

<td> 0,06290</td><td> 0,05190</td>

<td> 0,00800</td><td> 0,00750</td>

The resistance of the heat seals of Examples 5, 6, 7 and

9 and Comparative Examples 1 to 4 were measured using a

Model 12AS Heat Sealer from Packaging Industries, Inc. and a

Tinius Olsen Stress Test.

Prior to the test, each packaging strap / strip of Examples 5, 6 and 9 and Comparative Examples 1 and 4 were heat sealed to themselves.

Example 7 and Comparative Examples 2 and 3 each were sealed to a polyethylene film prior to testing.

Heat seals have been achieved using a 1.0 inch sealing bar at a pressure

43/43 bar between 30 and 40 psi and a time duration of one second.

The heat seal strengths have been determined to be between 180 ° F (82 ° C) to 320 ° F (160 ° C) substantially in accordance with ASTM F 88-94 and D952, both of which are hereby incorporated by reference.

Heat sealing resistance is reported in grams per inch (1g / 2.54cm)

The results of said examples (“Ex”) and comparative examples (“CEx”) are shown in Table 3.

Table 3

Comparison of Heat Sealing Strength

<td>Temp. (° F)</td><td>Ex.5</td><td>Ex.6</td><td>Ex.7</td><td>Ex.9</td><td>CEx.1</td><td>CEx.2</td><td>CEx.3</td><td>CEx.4</td>

<td> .180</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td> 200</td><td> 0</td><td> 479</td><td> 0</td><td> 304</td><td> 349</td><td> 0</td><td> 0</td><td> 538</td>

<td> 220</td><td> 2149</td><td> 3571</td><td> 0</td><td> 1960</td><td> 829</td><td> 0</td><td> 0</td><td> 1289</td>

<td> 240</td><td> 2628</td><td> 4654</td><td> 151</td><td> 2622</td><td> 1212</td><td> 5</td><td> 4</td><td> 1349</td>

<td> 260</td><td> 2613</td><td> 5481</td><td> 2912</td><td> 2919</td><td> 1764</td><td> 91</td><td> 53</td><td> 1864</td>

<td> 280</td><td> 2605</td><td> 5947</td><td> 3720</td><td> 3249</td><td> 1829</td><td> 245</td><td> 314</td><td> 1881</td>

<td> 300</td><td> 3571</td><td> 5644</td><td> 3720</td><td> 3205</td><td> 1695</td><td> 706</td><td> 649</td><td> 1864</td>

<td> 320</td><td> 3763</td><td> 6316</td><td> 4087</td><td></td><td> 1641</td><td> 776</td><td> 698</td><td> 1562</td>

It will be apparent to those skilled in the art that modifications and additions can be made to the various embodiments described above, without departing from the true scope and spirit of the present invention.

It should be understood that this invention is not intended to be unduly limited to the illustrative embodiments noted herein and that such embodiments are present in an exemplary manner only with the scope of the invention intended to be limited only by the claims that follow here.

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