Oxygen scavenging films

Abstract

The invention discloses oxygen scavenging films having at least one oxygen scavenging layer comprising a blend of ethylene/methyl acrylate/cyclohexene methyl acrylate copolymer (EMCM) as oxygen scavenger resin and a catalyst in a carrier resin, and an outer substrate layer having a thickness greater than 5% with respect to the total thickness of the film. The invention also relates to a process for the manufacturing of such films, to the use of said films in food packaging and to the packages obtained therefrom.

Claims

1. A multilayer oxygen scavenging film comprises: A) a first outer sealant layer, comprising from 5 to 25% by weight of a masterbatch comprising a zeolite and zinc oxide and from 5 to 15% by weight of a masterbatch comprising a zeolite, B) one oxygen scavenging layer comprising a blend of from 15 to 5% by weight of a catalyst in a carrier resin and from 85 to 95% by weight of ethylene/methyl acrylate/cyclohexene methyl acrylate copolymer (EMCM), wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA), C) one bulk layer comprising from 10 to 50% by weight of very low density ethylene/butene copolymer, and from 50 to 90% by weight of low density polyethylene homopolymer, D) one adhesive layer comprising a binary blend of from 48 to 58% by weight of isocyanate- aromatic and from 42 to 52% by weight of polyol-polyester coreactant or a ternary blend of from 3 to 13% by weight of polyol-polyester coreactant, from 48 to 58% by weight of ethyl acetate and from 34 to 44% by weight of isocyanate-aromatic isocyanate, and E) a second outer substrate layer comprising PET, wherein said second outer substrate layer E) has a thickness greater than 5% with respect to the total thickness of the film.

2. A multilayer oxygen scavenging film according to claim 1, wherein the first outer sealant layer further comprises a material selected from very low density ethylene/alpha olefin copolymer and low density polyethylene homopolymer.

3. A multilayer oxygen scavenging film according to claim 1, wherein the first outer sealant layer comprises at least an antiblock agent.

4. A multilayer oxygen scavenging film according to claim 1, wherein the at least one adhesive layer further comprises a material selected from one or more polyolefins, one or more modified polyolefins and a blend thereof.

5. A multilayer oxygen scavenging film according to claim 1, wherein the second outer substrate layer comprising the PET is coated with a metal oxide.

6. A multilayer oxygen scavenging film according to claim 1, wherein the total thickness of the film may vary from 10 to 100 microns.

7. A multilayer oxygen scavenging film according to claim 1, wherein the thickness of the oxygen scavenging layer may vary from 10 to 30 microns.

8. A multilayer oxygen scavenging film according to claim 1, wherein the oxygen scavenging layer may represent from 10 to 47% of the total thickness of the film.

9. A multilayer oxygen scavenging film according to claim 1, wherein the thickness of the second outer substrate layer may vary from 10 to 30 microns; and wherein the second outer substrate layer represent from 6 to 47% of the total thickness of the film.

10. A multilayer oxygen scavenging film comprising A) a first outer sealant layer optionally comprising from 5 to 15% by weight of a masterbatch comprising a zeolite, zinc oxide and magnesium oxide; B) one oxygen scavenging layer comprising a blend of from 15 to 5% by weight of a catalyst in a carrier resin and from 85 to 95% by weight of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA); C) one bulk layer comprising from 5 to 15% by weight of a masterbatch comprising a zeolite, from 25 to 35% by weight of very low density ethylene/butene copolymer, and from 70 to 50% by weight of low density polyethylene homopolymer; D) one adhesive layer comprising a binary blend of from 48 to 58% by weight of isocyanate- aromatic and from 42 to 52% by weight of polyol-polyester coreactant or a ternary blend of from 3 to 13% by weight of polyol-polyester coreactant, from 48 to 58% by weight of ethyl acetate and from 34 to 44% by weight of isocyanate-aromatic isocyanate; E) a second outer substrate layer comprising PET, optionally aluminum oxide coated, having a thickness greater than 5% with respect to the total thickness of the film.

11. A multilayer oxygen scavenging film according to claim 10, wherein the thickness of the second outer substrate layer may vary from 10 to 30 microns; and wherein the second outer substrate layer represent from 6 to 47% of the total thickness of the film.

12. A multilayer oxygen scavenging film according to claim 10, wherein the thickness of the oxygen scavenging layer may vary from 10 to 30 microns and represents 10 to 47% of the total thickness of the film.

13. A multilayer oxygen scavenging film comprising A) a first outer sealant layer comprising from 5 to 15% by weight of a masterbatch comprising ceramic spheres (beads)-alkali-alumino-silicate ceramic; B) one oxygen scavenging layer comprising a blend of from 15 to 5% by weight of a catalyst in a carrier resin and from 85 to 95% by weight of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA); C) one bulk layer comprising from 10 to 50% by weight of very low density ethylene/butene copolymer, and from 50 to 90% by weight of low density polyethylene homopolymer; D) one adhesive layer comprising a binary blend of from 48 to 58% by weight of isocyanate- aromatic and from 42 to mm % by weight of polyol-polyester coreactant or a ternary blend of from 3 to 13% by weight of polyol-polyester coreactant, from 48 to 58% by weight of ethyl acetate and from 34 to 44% by weight of isocyanate-aromatic isocyanate; E) a second outer substrate layer comprising PET, optionally aluminum oxide coated, having a thickness greater than 5% with respect to the total thickness of the film.

14. A multilayer oxygen scavenging film according to claim 13, wherein the thickness of the second outer substrate layer may vary from 10 to 30 microns; and wherein the second outer substrate layer represent from 6 to 47% of the total thickness of the film.

15. A multilayer oxygen scavenging film according to claim 13, wherein the thickness of the oxygen scavenging layer may vary from 10 to 30 microns and represents from 10 to 47% of the total thickness of the film.

16. A process for manufacturing a film according to claim 1 comprises: a) providing a coextruded film comprising the first outer sealant layer, the oxygen scavenging layer and the at least one bulk layer; b) providing a substrate comprising PET; and c) adhering the coextruded film to the substrate with the adhesive.

17. A package comprising a container, a product and a lid comprising the oxygen scavenging film according to claim 1 sealed onto the container.

18. A bag, or pouch or multi-compartment tray-less package made of the oxygen scavenging film according to claim 1 sealed onto itself.

19. A bag, a pouch or multi-compartment tray-less package made of the oxygen scavenging film according to claim 1 sealed onto itself and containing a product.

20. A method of using the oxygen scavenging film according to claim 1 comprising the step of packaging food within the scavenging film.

Description

DETAILED DESCRIPTION OF INVENTION

(1) In one aspect, the present invention is a multilayer oxygen scavenging film comprising:

(2) A) a first outer sealant layer, optionally comprising at least one odour absorber,

(3) B) at least one oxygen scavenging layer,

(4) C) at least one bulk layer,

(5) D) at least one adhesive layer, and

(6) E) a second outer substrate layer comprising a material selected from polyester, aromatic polyester, and PET,

(7) wherein

(8) said at least one oxygen scavenging layer B) comprises a blend of ethylene/methyl acrylate/cyclohexene methyl acrylate copolymer (EMCM) as oxygen scavenger resin and a catalyst in a carrier resin, and

(9) said second outer substrate layer E) has a thickness greater than 5% with respect to the total thickness of the film.

(10) Suitable catalysts used in said blend are transition metals that can readily interconvert between at least two oxidation states. The catalyst can be in the form of a transition metal salt, compound or complex, with the metal selected from the first, second or third transition series of the Periodic Table. The oxidation state of the metal when introduced is not necessarily that of the active form The metal preferably is Rh, Ru, or one of the elements in the series of Sc to Zn (i.e., Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), more preferably at least one of Ti, Mn, Fe, Co, Ni, and Cu, and most preferably Ti and Co. Suitable anions for such metals include, but are not limited to, chloride, acetate, oleate, stearate, palmitate, caprylate, linoleate, tallate, 2-ethylhexanoate, neodecanoate, and naphthenate as well as their mixtures. Representative salts include cobalt (II) 2-ethylhexanoate, cobalt oleate, cobalt stearate and cobalt (II) neodecanoate, as well as titanium alkoxydes such as titanium (IV) isopropoxide. The metal salt may also be an ionomer, in which case a polymeric counterion is employed. Such ionomers are well known in the art.

(11) Suitable carrier resins are polyester carrier resins such as ethylene vinyl acetate (EVA) or ethylene methyl acrylate (EMA).

(12) Optionally, said blend may further comprise a photoinitiator.

(13) Suitable photoinitiators are known to those skilled in the art., see e.g., PCT publication WO97/07161, WO97/44364, WO98/51758, and WO98/51759, the teaching of which are incorporated herein by reference. Specific examples of suitable photoinitiators include, but are not limited to, benzophenone, and its derivatives, such as methoxybenzophenone, dimethoxybenzophenone, dimethylbenzophenone, diphenoxybenzophenone, allyloxybenzophenone, diallyloxybenzophenone, dodecyloxybenzophenone, dibenzosuberone, 4,4′-bis(4-isopropylphenoxy)benzophenone, 4-morpholinobenzophenone, 4-aminobenzophenone, tribenzoyl triphenylbenzene, tritoluoyl triphenylbenzene, 4,4′-bis(dimethylamino)-benzophenone, acetophenone and its derivatives, such as, o-methoxy-acetophenone, 4′-methoxyacetophenone, valerophenone, hexanophenone, a-phenyl-butyrophenone, p-morpholinopropiophenone, benzoin and its derivatives, such as, benzoin methyl ether, benzoin butyl ether, benzoin tetrahydropyranyl ether, 4-o-morpholinodeoxybenzoin, substituted and unsubstituted anthraquinones, a-tetralone, acenaphthenequinone, 9-acetylphenanthrene, 2-acetyl-phenanthrene, 10-thioxanthenone, 3-acetyl-phenanthrene, 3-acetylindole, 9-luorenone, 1-indanone, 1,3,5-triacetylbenzene, thioxanthen-9-one, isopropylthioxanthen-9-one, 3 xanthene-9-one, 7-H-benz[de]anthracen-7-one, 1′-acetonaphthone, 4 2′-acetonaphthone, acetonaphthone, benz[de]anthracen-7-one, 1′-acetonaphthone, 2′-acetonaphthone, acetonaphthone, benz[a]anthracene-7,12-dione, 2,2-dimethoxy-2-henylacetophenone, a,a-diethoxyacetophenone, a,a-dibutoxyacetophenone, 4-benzoyl-4′-methyl(diphenyl sulfide) and the like. Single oxygen-generating photosensitizers such as Rose Bengal, methylene blue, and tetraphenylporphine as well as polymeric initiators such as poly(ethylene carbon monoxide) and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] also can be used. The photoinitiator if present, may be carried on a polyester resin. When a photoinitiator is present, it can enhance and/or facilitate the initiation of oxygen scavenging by the oxygen scavenger blend upon exposure to radiation. When actinic radiation is used, photoinitiators can provide initiation at longer wavelengths which are less costly to generate and present less harmful side effects than shorter wavelengths. Oxygen scavenging can be initiated by exposing an article containing the oxygen scavenger blend to actinic or electron beam radiation, as described below.

(14) One or more antioxidants can be optionally incorporated into said blend to retard degradation of its components during compounding and film formation.

(15) Suitable antioxidants used in said blend include, but are not limited to, 2,6-di(t-butyl)-4-methylphenol (BHT), 2,2′-methylene-bis(6-t-butyl-p-cresol), triphenylphosphite, tris-(nonylphenyl)phosphite, dilauryithiodipropionate, vitamin E (a-tocopherol), octadecyl 3,5,-di-tert-butyl-4-hydroxyhydrocinnamate, tetrakis[methylene(3, 5-di-tert-butyl-4-hydroxyhydrocin namate)] methane and the like. When an antioxidant is included as part of the blend, the amount preferably is less than that which interferes with the scavenging activity of the resultant layer, film, or article after initiation has occurred. The amount needed in a given oxygen scavenger blend can depend on the components present therein, the particular antioxidant used, the degree and amount of thermal processing used to form the shaped article, and the dosage and wavelength of radiation applied to initiate oxygen scavenging.

(16) Other additives that also can be included in said blend include, but are not necessarily limited to, fillers, pigments, dyestuffs, processing aids, plasticizers, antifog agents, antiblocking agents, and the like. The mixing of the components listed above can be accomplished by melt blending at a temperature in the range of 50° C. to 300° C. However, alternatives such as the use of a solvent followed by evaporation may also be employed.

(17) The amounts of the components used in the blend affect the use and effectiveness of the blend itself. Thus, the amounts of the oxygen scavenger component (EMCM), catalyst, and anyone of photoinitiator, antioxidant, polymeric diluent(s), additive(s), etc. if any, can vary depending on the desired packaging article and its end use. For example, one of the primary functions of the oxygen scavenger component is to react irreversibly with oxygen during the scavenging process, while a primary function of the catalyst is to facilitate this process. Thus, to a large extent, the amount of the oxygen scavenger component affects the oxygen scavenging capacity of the packaging article, i.e., the amount of oxygen that the layer can consume, while the amount of catalyst affects the rate at which oxygen is consumed as well as the induction period.

(18) The amount of EMCM contained in the blend can range from about 1 to almost about 100%, such as from about 5 to about 97.5%, from about 10 to about 95%, from about 15 to about 92.5%, and from about 20 to about 90%, with all the foregoing percentages being by weight of the blend or layer made therefrom.

(19) Typically, the amount of catalyst can range from 0.001 to 1% by wt. of the total weight of the blend, based on the metal content only (i.e., excluding ligands, counterions, etc.).

(20) The amount of photoinitiator, if present, can depend on the amount and type of cyclic unsaturation present in the oxygen scavenger component, the wavelength and intensity of radiation used, the nature and amount of antioxidants used, and the type of photoinitiator used. The amount of the photoinitiator, if present, may range from about 0.01 to about 10% by wt. of the total weight of the blend.

(21) The antioxidant(s), if present, can be used in an amount of from about 0.01 to about 1% by wt. of the total weight of the composition.

(22) Any further additives employed, if present, normally do not make up more than 10%, preferably no more than about 5% by weight of the total weight of the blend.

(23) The multilayer oxygen scavenging film of the present may comprise from 1 to 5, preferably from 1 to 3, more preferably one oxygen scavenging layer(s).

(24) In one embodiment, said at least one oxygen scavenging layer comprises a blend of from about 15 to about 5% of a catalyst in a carrier resin and from about 85 to about 95% of EMCM; such as a blend of about 10% of a catalyst in a carrier resin and about 90% of EMCM.

(25) Said catalyst carrier resin in one embodiment comprises ethylene vinyl acetate copolymer (EVA) or ethylene methyl acrylate copolymer (EMA).

(26) In one embodiment, said catalyst comprises cobalt oleate or cobalt (II) neodecanoate.

(27) Polymers that may be used for the first outer sealant layer include any resin typically used to formulate packaging films with heat seal properties such as polyolefin copolymers including ethylene polymer or copolymer, ethylene/alpha olefin copolymers, ethylene/vinyl acetate copolymer, ionomer resin, ethylene/acrylic acid or methacrylic acid copolymer, ethylene/acrylate or methacrylate copolymer, or blends of any of these materials. Preferably the sealant layer of the invention comprises very low density ethylene/alpha olefin copolymer and low density polyethylene homopolymer. More preferably the sealant layer comprises very low density ethylene/butene copolymer and low density polyethylene homopolymer.

(28) In one embodiment said first outer sealant layer comprises at least an odour absorber agent.

(29) Suitable odour absorber agents are zeolites, metal oxides, such as zinc oxide and magnesium oxide, or a mixture thereof. Said agents are preferably carried on a resin to produce a masterbatch. Suitable resins that may be used in the odour absorber masterbatch are the same listed with reference to the sealant layer above. Preferred resins used in said masterbatch are ethylene polymer and copolymer and ethylene/alpha olefin copolymers. More preferred polymers are low density ethylene/hexene copolymer, low density ethylene/octene copolymer, propylene/ethylene copolymer, low density polyethylene or very low density polyethylene. The percentage of the at least an odour absorber agent is preferably from about 20 to about 40% in weight of the total weight of the masterbatch, according to the quantities of Volatile Compounds (VOCs) generated by the oxygen scavenging chemistry to be scavenged and removed.

(30) In one embodiment the sealant layer comprises one odour adsorber masterbatch, comprising a zeolite and optionally zinc oxide and/or magnesium oxide; preferably, the first outer sealant layer comprises from about 5 to about 15% by weight of a masterbatch comprising a zeolite, zinc oxide and magnesium oxide.

(31) In another embodiment the sealant layer comprises two odour adsorber masterbatches, one comprising a zeolite and zinc oxide and the other comprising a zeolite; preferably, the first outer sealant layer comprises from about 15 to about 25% by weight of a masterbatch comprising a zeolite and zinc oxide and from about 5 to about 20% by weight of a masterbatch comprising a zeolite.

(32) In another embodiment the first outer sealant layer comprises at least an antiblock agent.

(33) Suitable antiblock agents that may be used in the present films are ceramic spheres (beads)—alkali-alumino-silicate ceramic. Said agents can be carried on a resin to produce a masterbatch. The percentage of the at least an antiblock agent is preferably from about 5 to about 15% in weight of the total weight of the masterbatch. Suitable resins that may be used in antiblock masterbatch are the same listed with reference to the sealant layer above. In one embodiment, the sealant layer comprises from about 5 to about 15% by weight a masterbatch comprising ceramic spheres (beads)—alkali-alumino-silicate ceramic.

(34) In another embodiment the first outer sealant layer does not comprise nor an odour absorber agent nor an antiblock agent.

(35) Polymers that may be used for the at least one bulk layer are the same listed with reference to the sealant layer above. In one embodiment said at least one bulk layer comprises at least an odour absorber agent, optionally carried on a resin to produce a masterbatch. Suitable odour absorber agents and suitable resins to produce a masterbatch are the same listed above.

(36) The multilayer oxygen scavenging film of the present may comprise from 1 to 5, such as from 1 to 3, such as one bulk layer(s).

(37) The at least one adhesive layer is disposed between the respective layers in case a sufficient adhesion is not ensured between adjacent layers. The adhesive is selected for adhesion, flexibility, and favorable organoleptic properties as required so that the resultant film is substantially free of wrinkles, exhibits good flatness, and has the appropriate coefficient of friction (COF) for winding, slitting and final converting processes.

(38) Polymers that may be used for the adhesive layer are selected among the group consisting of one or more polyolefins, one or more modified polyolefins and a blend of the above. Specific, not limitative, examples thereof include ethylene-vinyl acetate copolymers, ethylene-(meth)acrylate copolymers, ethylene-alpha-olefin copolymers, any of the above modified with carboxylic or preferably anhydride functionalities, elastomers, and a blend of these resins.

(39) Suitable resins are ADMER NF 538E by Mitsui Chemical, Plexar PX3227X09 or Plexar PX3227 by Lyondell Basell, OREVAC 18211 by Arkema and BYNEL 3101, Bynel 39E660 or Bynel CXA21E6787 by DuPont. Other suitable adhesive resins are blend of isocyanate aromatic and polyol-polyester coreactant such as PURELAM™ supplied by Ashland. Other adhesive resins are blends of polyol-polyester coreactant, ethyl acetate and isocyanate-aromatic isocyanate, such as those supplied by Dow Chemical and ethyl acetate supplied by Eastman Chemical.

(40) The multilayer oxygen scavenging film of the present may comprise from 1 to 5, such as from 1 to 3, such as one adhesive layer(s).

(41) Polymers that may be used for the second outer substrate layer are selected from the group consisting of polyamides, polyesters and styrene-based (co)polymers. Blends of such classes of resins can be used. For example, polyesters of ethylene glycol and terephthalic acid, i.e. poly(ethylene terephthalate) (PET) are used; optionally PET may be coated with a metal oxide, such as aluminum oxide or silicon oxide. Preferably the polyester is 100% PET, optionally coated with aluminum oxide. In one embodiment, the substrate is printed prior to lamination.

(42) The multilayer oxygen scavenging film of the present invention may have from 5 to 17 layers, such as 11, or 5 layers.

(43) Preferred multilayer structures according to the present invention are:

(44) A/B/C/D/E, A/C/B/D/E (5 layers),

(45) A/B/C/B/D/E, A/C/B/C/D/E (6 layers),

(46) A/B/D/C/B/D/E, A/C/D/B/C/D/E, A/D/B/C/B/D/E, (7 layers),

(47) A/D/B/D/C/B/D/E, A/D/C/D/B/C/D/E, A/D/C/D/B/B/D/E, (8 layers),

(48) A/D/B//BD/C/B/D/E, A/D/C/D/B/B/C/D/E, A/D/C/D/B/D/B/D/E, (9 layers),

(49) A/C/D/B//B/D/C/B/D/E, A/C/D/C/D/B/B/C/D/E, A/C/D/C/D/B/D/B/D/E, (10 layers),

(50) A/D/B/D/C/D/B/D/C/D/E, A/D/B/D/C/D/B/D/B/D/E (11 layers);

(51) wherein:

(52) A=first outer sealant layer,

(53) B=oxygen scavenging layer,

(54) C=bulk layer,

(55) D=adhesive layer,

(56) E=second outer substrate layer.

(57) In one embodiment the multilayer oxygen scavenging film of the present invention comprises

(58) A) a first outer sealant layer comprising from about 5 to about 25% by weight a masterbatch comprising a zeolite and zinc oxide and from about 5 to about 15% by weight a masterbatch comprising a zeolite;

(59) B) one oxygen scavenging layer comprising a blend of from about 15 to about 5% of a catalyst in a carrier resin and from about 85 to about 95% of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA);
C) one bulk layer comprising from about 10 to about 50% by weight of very low density ethylene/butene copolymer, from about 50 to about 90% by weight of low density polyethylene homopolymer;
D) one adhesive layer comprising a binary blend of from about 48 to about 58% by weight of isocyanate-aromatic and from about 42 to 52% by weight of polyol-polyester coreactant or a ternary blend of from about 3 to about 13% by weight of polyol-polyester coreactant, from about 48 to 58% by weight of ethyl acetate and from about 34 to about 44% by weight of isocyanate-aromatic isocyanate;
E) a second outer substrate layer comprising PET, optionally aluminum oxide coated, having a thickness greater than 5% with respect to the total thickness of the film.

(60) In another embodiment the multilayer oxygen scavenging film of the present invention comprises

(61) A) a first outer sealant layer optionally comprising from about 5 to about 15% by weight a masterbatch comprising a zeolite, zinc oxide and magnesium oxide;

(62) B) one oxygen scavenging layer comprising a blend of from about 15 to about 5% of a catalyst in a carrier resin and from about 85 to about 95% of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA);
C) one bulk layer comprising from about 5 to about 15% by weight a masterbatch comprising a zeolite, from about 25 to about 35% by weight of very low density ethylene/butene copolymer, from about 70 to about 50% by weight of low density polyethylene homopolymer;
D) one adhesive layer comprising a binary blend of from about 48 to about 58% by weight of isocyanate-aromatic and from about 42 to mm % by weight of polyol-polyester coreactant or a ternary blend of from about 3 to about 13% by weight of polyol-polyester coreactant, from about 48 to 58% by weight of ethyl acetate and from about 34 to about 44% by weight of isocyanate-aromatic isocyanate;
E) a second outer substrate layer comprising PET, optionally aluminum oxide coated, having a thickness greater than 5% with respect to the total thickness of the film.

(63) In another embodiment the multilayer oxygen scavenging film of the present invention comprises

(64) A) a first outer sealant layer comprising from about 5 to about 15% by weight a masterbatch comprising ceramic spheres (beads)—alkali-alumino-silicate ceramic;

(65) B) one oxygen scavenging layer comprising a blend of from about 15 to about 5% of a catalyst in a carrier resin and from about 85 to about 95% of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate copolymer (EMA);
C) one bulk layer comprising from about 10 to about 50% by weight of very low density ethylene/butene copolymer, from about 50 to about 90% by weight of low density polyethylene homopolymer;
D) one adhesive layer comprising a binary blend of from about 48 to about 58% by weight of isocyanate-aromatic and from about 42 to mm % by weight of polyol-polyester coreactant or a ternary blend of from about 3 to about 13% by weight of polyol-polyester coreactant, from about 48 to 58% by weight of ethyl acetate and from about 34 to about 44% by weight of isocyanate-aromatic isocyanate;
E) a second outer substrate layer comprising PET, optionally aluminum oxide coated, having a thickness greater than 5% with respect to the total thickness of the film.

(66) The total thickness of the film of the present invention may vary within wide limits, e.g. from 10 to 100 microns, such as from 5 to 80 microns, 8 to 70 microns, and from 15 to 70 microns.

(67) The thickness of the at least one oxygen scavenging layer may vary within wide limits, e.g. from 10 to 30 microns, and from 15 to 25 microns. The at least one oxygen scavenging layer may represent about from 10 to about 47% of the total thickness of the film; such as about from 23 to about 39%; or about 30%.

(68) The thickness of the second outer substrate layer may vary within wide limits, e.g. from 10 to 30 microns, and from 15 and 25 micron. The second outer substrate layer may represent about from 6 to about 47% of the total thickness of the film; such as from 10 to about 39%; or about 20%.

(69) One or more of the layers of the film of the present invention may contain any of the additives conventionally employed in the manufacture of polymeric films. Thus, agents such as pigments, lubricants, anti-oxidants, radical scavengers, UV absorbers, thermal stabilisers, anti-blocking agents, surface active agents, slip aids, optical brighteners, gloss improvers, viscosity modifiers may be incorporated as appropriate. In particular, to improve the processing of the film in high speed packaging equipment, slip and/or anti-blocking agents may be added to one or both of the surface layers. The additives may be added in the form of a concentrate in a polyester carrier resin. The amount of additive is typically in the order of 0.2 to 5% by weight of the total weight of the layer.

(70) Multilayer films of the invention can be made using conventional extrusion, coextrusion, and/or lamination processes. Likewise, conventional manufacturing processes can be used to make a pouch, a bag, or other container from the film. Hermetic sealing of a pouch, bag, or other container made from the film of the invention will typically be preferable. The exact requirements of a container made from the film will depend on a variety of factors, including the chemical nature of the oxygen scavenger, amount of the oxygen scavenger, concentration of the oxygen scavenger in a host material or diluent, physical configuration of the oxygen scavenger, presence of hermetic sealing, vacuumization and/or modified atmosphere inside the container, initial oxygen concentration inside the container, intended end use of the oxygen scavenger, intended storage time of the container before use, level of initial dose of actinic radiation, etc.

(71) Another aspect of the present invention is a process for the manufacture of a film according to the first aspect of the present invention.

(72) Multilayer films of the present invention typically are prepared using coextrusion, extrusion coating, lamination or extrusion/lamination as taught in, for example, U.S. Pat. Nos. 5,350,622 and 5,529,833, the teachings of which are incorporated herein by reference.

(73) The process of the present invention also includes exposing the film according to the first aspect of the present invention to radiation so as to initiate oxygen scavenging at desired rates. The thermal radiation used in heating and processing polymers typically used in packaging films (e.g., 100-250° C.) advantageously does not trigger the oxygen scavenging reaction. The initiating radiation preferably is actinic, e.g., UV or visible light having a wavelength of from about 200 to about 750 nm, preferably of from about 200 4 to 600 nm, and most preferably from about 200 to 400 nm. Such light can be delivered in a continuous or pulsed manner. The film of the invention can be exposed to such radiation until it receives at least about 1 J/g of radiation, such as a dose in the range of about 10 to about 2000 J/g. The radiation also can be in the form of electron-beam radiation at a dosage of at least about 2 kiloGray 10 (kG), such as from about 10 to about 100 kG. Other potential sources of radiation include ionizing radiation such as gamma, X-ray, and corona discharge. Duration of exposure depends on several factors including, but not limited to, the amount and type of photoinitiator present, thickness of the layers to be exposed, thickness and opacity of intervening layers, amount of any antioxidant present, and the wavelength and intensity of the radiation source. Irradiation can occur during or after the film is prepared. If the resulting film is to be used to package an oxygen sensitive product, exposure can be just prior to, during, or after packaging. For best uniformity of radiation, exposure preferably occurs at a processing stage where the film is in the form of a flat sheet. For further information on initiation via irradiation, the reader is directed to PCT publications WO 98/05555 and WO 98/05703, as well as WO 97/13598, 97/13370, 97/13369, the teachings of which are incorporated herein by reference.

(74) The process described above assumes all processing steps plus the triggering can be done in the same location. If the triggering is to be accomplished at a different location, then a different process can be considered, such as activating the extruded film just after extrusion, placing the extruded film in barrier bags and shipping them to a converter. The converter can then laminate, cure, and slit the film before repackaging the film in an oxygen free environment. All these steps should be completed in as short a period as possible to enhance the scavenging capacity.

(75) One process for the manufacture of the multilayer oxygen scavenging film of the present invention described above comprises the following steps: 1) coextrusion of the first outer sealant layer, the at least one odour absorber, the at least one oxygen scavenging layer and the at least one bulk layer, 2) lamination of the resultant co-extruded film with the adhesive layer to the second outer substrate layer 3) curing and, 4) optionally, irradiation.

(76) Irradiation can be performed either on the extruded film (i.e. after step 1) or on the laminated film, after curing. Curing is typically done for a minimum of 24 hours.

(77) In one embodiment, irradiation is accomplished using electron-beam radiation, e.g. at a dosage of at least about 2 kiloGray 10 (kG), such as from about 10 to about 100 kG.

(78) A third aspect of the present invention is a package comprising a container, a product and a lid comprising the oxygen scavenging film of the first aspect of the present invention sealed onto said container.

(79) Typically the surface of the container in contact with the product, i.e. the surface involved in the formation of the seal with the lidding film, comprises a polyester resin, usually an amorphous polyester resin (APET). For instance, the container can comprise a cardboard coated with polyester, or it can be integrally comprise a polyester resin. Examples of suitable containers for the package of the invention are CPET, APET, APET/CPET, either foamed or non-foamed, i.e. solid, or aluminum containers.

(80) The package is produced by techniques well-known to those skilled in the art. Once the food to be packaged has been introduced into the container, the bi-axially oriented coated polyester film of the invention is sealed to the container by means of temperature and/or pressure using conventional sealing techniques and equipment. The film is placed on the container such that the heat-sealable coating is in contact with the surface of the container. Sealing is carried out by means of a heated frame at temperatures of from 100° C. to 200° C., 120° C. to 200° C. at a pressure of 2 to 10 bar, 4 to 8 bar. Sealing times are typically in the order of 0.3 to 2.0 seconds, 0.5 to 1.0 seconds. The heat generated by the sealing frame, regardless of the short sealing times, promotes the shrinkage of the film in both directions without distortion of the container to give a taut hermetically sealed lid. No film excess is needed to seal the container as the shrink of the film takes place only after the film is tightly held between the sealing frame and the rim of the container.

(81) A fourth aspect of the present invention is a bag, or pouch or multi-compartment tray-less package made of the oxygen scavenging film of the first aspect of the present invention sealed onto itself. A common method of forming said bags, or pouches or multi-compartment tray-less packages is by means of form-fill-seal (FFS) machines, such as a horizontal form-fill-seal (HFFS) or a vertical form-fill seal (VFFS) machine.

(82) A FFS machine, either horizontal or vertical, typically includes a former for forming a flat web of film into a tubular configuration, a longitudinal sealer to seal the overlapped longitudinal edges of the film in the tubular configuration, a conveyor for feeding the products into the tubular film one after the other in suitably spaced configuration, or a feeding tube in case of a VFFS machine, and a transverse sealer for sealing the tubular film in a cross-wise direction to separate the products into discrete packages.

(83) The transverse sealer may be operated to simultaneously seal the bottom of the leading pouch and the front of the following pouch and sever the two seals as well as the leading package from the front sealed tubing.

(84) In the HFFS process, a method of making a package comprises:

(85) providing a lay-flat web;

(86) advancing the lay-flat web to a forming device to convert the lay-flat web into a folded web;

(87) advancing a food product to the forming device such that the folded web envelopes the product;

(88) longitudinally sealing the folded web to make a longitudinal seal;

(89) transversely sealing the folded web, with the product therein, to produce a leading transverse seal to define a first pouch;

(90) advancing the folded web, with the leading transverse seal, forward a predetermined distance;

(91) transversely sealing the folded web to produce a trailing transverse seal in the first pouch, and a leading transverse seal in a second pouch, the second pouch disposed upstream of the first pouch; and

(92) cutting the folded web to separate the first pouch from the second pouch to form an individual package. In the FFS processes, while the transverse seals are always fin seals, the longitudinal seal can be either a fin seal or a lap seal, i. e. a seal where the heat sealable layer of the film is sealed to the outermost layer of the same film.

(93) The outermost or external layer is selected for its heat resistance during the sealing step. For example, it is advantageous to select for this layer a polymer having a melting point higher than the sealing temperature.

(94) The bag, pouch or multi-compartment tray-less package can be irradiated in case the oxygen scavenging film has not been irradiated during its manufacturing, in order to initiate oxygen scavenging. The packages described above have wide applications, including for food packaging, such as for, dried milk, meat and cheese, smoked and processed luncheon meats.

(95) When the product will be loaded into, for example, a bag made of the film of the invention, its open end will be closed by heat-sealing or by applying a clip, e.g. of metal.

(96) A fifth aspect of the present invention is a bag, a pouch or multi-compartment tray-less package made of the oxygen scavenging film of the first aspect of the present invention sealed onto itself and containing the product.

(97) A sixth aspect of the present invention is the use of the oxygen scavenging film according to the first aspect of the present invention for packaging food, in particular for food containing oxygen sensitive unsaturated oils, such as dried milk.

(98) The multilayer oxygen scavenging film for use according to the sixth aspect of the present invention comprises in one embodiment:

(99) A) a first outer sealant layer comprising from about 5 to about 25% by weight a masterbatch comprising zeolite and zinc oxide from about 5 to about 15% by weight a masterbatch comprising zeolite;

(100) B) an oxygen scavenging layer comprising a blend of from about 15 to about 5% by weight of a catalyst in a carrier resin and from about 85 to about 95% by weight of EMCM, wherein the catalyst is cobalt oleate or cobalt (II) neodecanoate and the catalyst carrier resin is ethylene methyl acrylate (EMA);
C) a bulk layer comprising from about 10 to about 50% by weight of very low density ethylene/butene copolymer, from about 50 to about 90% by weight of low density polyethylene homopolymer;
D) an adhesive layer comprising a binary blend of from about 48 to about 58% by weight of isocyanate-aromatic and from about 42 to 52% by weight of polyol-polyester coreactant or a ternary blend of from about 3 to about 13% by weight of polyol-polyester coreactant, from about 48 to 58% by weight of ethyl acetate and from about 34 to about 44% by weight of isocyanate-aromatic isocyanate; and
E) a second outer substrate layer comprising PET, optionally coated with aluminum oxide and having a thickness greater than 5% with respect to the total thickness of the film.

EXAMPLES

(101) The present invention can be further understood by reference to the following examples that are merely illustrative and are not to be interpreted as a limitation to the scope of the present invention that is defined by the appended claims.

(102) In the following examples the polymers indicated in Table 1 below have been employed.

(103) TABLE-US-00001 TABLE 1 Polymers Parameters Tradename Supplier Chemical Nature Acronym/Name Analysis Value Units EXACT 3024 ExxonMobil Polyethylene, VLDPE1 Density 0.905 g/cm.sup.3 Very Low Melt Flow 4.50 g/10 min Density Rate (Cond. Ethylene/Butene 190° C./ Copolymer - 02.16 kg Linear, Single (E)) Site Melting 97 ° C. Point Vicat 87 ° C. softening point Crystallization 82 ° C. point AFFINITY PL DOW Polyethylene, VLDPE2 Comonomer 12 % 1850G Very Low content Density Density 0.9020 g/cm.sup.3 Ethylene/Octene Melt Flow 3 g/10 min Copolymer - Rate (Cond. Branched, 200° C./ Single Site 02.16 kg) Melting 97 ° C. Point Vicat 85 ° C. softening point ATTANE DOW Polyethylene, VLDPE3 Additives 200 ppm 4203 Very Low Bulk 0.53 g/cm.sup.3 Density (apparent) Ethylene/Octene Density Copolymer - Comonomer 11.5 % Linear, content Ziegler/Natta Density 0.9052 g/cm.sup.3 Gel area 0.82 mm.sup.2 Melt Flow 0.8 g/10 min Rate (Cond. 190° C./ 02.16 kg) Melt flow 8.6 ratio Melting 123 ° C. Point MB50-802 Dow Polydimethylsiloxane LDPE1 Additives 50 % Corning in Density 1.03 g/cm.sup.3 Polyethylene, Bulk 0.6 g/cm.sup.3 Low Density - (Apparent) High Molecular Density Weight Siloxane Melt Flow 8.0 g/10 min Rate 10414-08 Colortech Zeolite in LDPE2 Ash 19.6 % Polyethylene, Density 1.02 g/cm.sup.3 Low Density Melt Flow 6 g/10 min (odour absorber) Rate (Cond. 190° C./ 02.16 kg) Petrothene LyondellBasell Polyethylene LDPE3 Density 0.9185 g/cm.sup.3 NA952000 Industries Low Density Melt Flow 2.0 g/10 min Homopolymer - Rate Free Radical Toppan Toppan Polyester, PET1 Density 1.4 g/cm.sup.3 GX-P-F Biaxially Thickness 12 micron Oriented - Aluminum Oxide Coated FlexPET FLEX Polyester, PET2 Density 1.4 g/cm.sup.3 F-CHE AMERICA Biaxially Thickness 0.48 Mils S, S.A DE Oriented; One C. V. side Chemicall/PET - FlexPET FLEX Polyester, PET3 F-PLF AMERICA Biaxially S, S.A DE Oriented - C. V. Aluminum Oxide Coated Orrex Orrex Cobalt Catalyst Oxygen Comonomer 23 % OSP110M Plastic in Scavenging MB content Ethylene/Methyl (OSMB1) (MethylAcrylate) Acrylate Density 0.955 g/cm.sup.3 Copolymer Melt Flow 3.5 g/10 min Rate n.a. in-house Titanium Oxygen n.a. n.a. n.a. catalysed Scavenging MB Ethylene/Methyl (OSMB2) Acrylate/Cyclohexene Methyl Acrylate Copolymer, 50% by weight EMA 50% by weight Cyclohexene units POLYBATCH Schulman AntiBlock and LDPE4 Additives 10 % FSU 105E Slip in Melt Flow 20 g/10 min Polyethylene, Rate (Cond. Low Density 190° C./ 02.16 kg (E)) Ash 10 % Density 0.98 g/cm.sup.3 Moisture 1.5 % content Number 43 No./g Pellets Polybatch Schulman Silica in LDPE5 Melt Flow 17 g/10 min AB-5 Polyethylene, Rate (Cond. Low Density - 190° C./ Amorphous 02.16 kg Silica (E)) Density 0.96 g/cm.sup.3 LDPE 312E DOW Polyethylene LDPE6 Melt Flow 0.75 g/10 min Low Density Rate (Cond. Homopolymer - 190° C./ Free Radical 02.16 kg (E)) Density 0.923 g/cm.sup.3 POLYBATCH Schulman AntiBlock and LDPE7 Melt Flow 1.1 g/10 min FSU 105E Slip in Rate (Cond. Polyethylene, 190° C./ Low Density 02.16 kg (E)) Melting 99 ° C. Point Density 0.902 g/cm.sup.3 Vicat 86 ° C. Softening point POLYBATCH Schulman Primary and LDPE8 Density 0.93 g/cm.sup.3 AO-25 Secondary AO in Polyethylene, Low Density - Proprietary POLYBATCH Schulman Fluoropolymer in LDPE9 Density 0.918 g/cm.sup.3 AMF 702 Polyethylene, Low Density AMPLIFY TY DOW Maleic LLDPE-md1 Melt Flow 1.4 g/10 min 1451 Anhydride- Rate (Cond. Modified 190° C./ Polyethylene, 02.16 kg Linear Low (E)) Density Blend - Density 0.9080 g/cm.sup.3 Rubber-Modified SOARNOL Nippon Hydrolyzed EVOH Comonomer 38.00 % ET3803 Gohsei Ethylene/Vinyl content Acetate Crystallization 58 ° C. Copolymer - point Between 30-40 Melting 173 ° C. mole % Ethylene Point Density 1.17 g/cm.sup.3 Moisture Max. % Content 0.3 LDPE 310E DOW Polyethylene LDPE10 Melt Flow 0.75 g/10 min Low Density Rate (Cond. Homopolymer - 190° C./ Free Radical 02.16 kg (E)) Density 0.9235 g/cm.sup.3 ENGAGE DOW Polyethylene, VLDPE5 Melt Flow 0.5 g/10 min 8150 Very Low Rate (Cond. Density 190° C./ Ethylene/Octene 02.16 kg Copolymer - (E)) Linear, Single Crystallization 42 ° C. Site point Melting 55 ° C. Point Density 0.868 g/cm.sup.3 Vicat 46 ° C. softening point Engage 8402 DOW Polyethylene, VLDPE6 Melt Flow 30 g/10 min Very Low Rate (Cond. Density 190° C./ Ethylene/Octene 02.16 kg Copolymer - (E)) Branched, Density 0.902 g/cm.sup.3 Single Site n.a. In-House Adhesive made ADHESIVE 2 by 53.27% PURELAM 9500 and 46.73% PURELAM 9240 as defined below: PURELAM Ashland Isocyanate - Aromatic Percent Min. % 9500 NCO 19.5-Max. 21.5 Viscosity Min. mPa .Math. sec 1800-Max. 4000 PURELAM Ashland Polyol - Polyester Coreactant Hydroxyl 230 mg 9240 Value KOH/g Viscosity 1450 mPa .Math. sec n.a. In-House Adhesive made ADHESIVE 1 by ADCOTE 532B 8.00%, TRUE 53.00%, ADCOTE 532A 39.00% as defined below: ADCOTE Dow Polyol - Polyester Coreactant Density 1.1260 g/cm.sup.3 532B Chemical High Purity Eastman Ethyl Acetate Acid 0.010 mg Ethyl Chemical Number KOH/g Acetate Density 0.9015 g/cm.sup.3 Moisture 0.03 % Content Purity 99.5 % ADCOTE Dow Isocyanate - Aromatic Isocyanate Density 1.0540 g/cm.sup.3 532A Chemical n.a. In-House Adhesive made ADHESIVE 3 by HERBERTS EPS 72 EA 44.84%, HARDENER KN 75 4.94%, ETHYL ACETATE 50.22% as defined below: HERBERTS Bostik Polyol - Density 1.15 g/cm.sup.3 EPS 72 EA Polyester Coreactant Viscosity Solution 1800 mPa .Math. sec HARDENER Bostik Isocyanate - Viscosity Solution 1.17 mPa .Math. sec KN 75 Aromatic Isocyanate ETHYL Brenntag Ethyl Acetate Boiling Point Range 80 ° C. ACETATE Density 0.8990 g/cm.sup.3 Moisture Content max % 0.1 Purity min 95 % Refractive Index min max 1.365 1.373

(104) The composition of Masterbatches 1-3 is reported in Table 2.

(105) TABLE-US-00002 TABLE 2 Masterbatch composition Chemical Parameters % Tradename Supplier Nature Acronym Analysis Value Units Masterbatch 1 25% Exceed ExxonMobil linear Low LLDPE1 density 0.9 g/cc 1012HA Density melt 1 g/10 min Ethylene/Hexene flow Copolymer - rate, Linear, Single 190, ° C., Site 2.16 kg, ASTM D1238 melting 115 ° C. point 25% DOWLEX DOW Linear Low LLDPE2 density 0.92 g/cc 2045.03 Density melt 1.1 g/10 min Ethylene/Octene flow Copolymer - rate, Linear, 190, ° C., Ziegler/Natta 2.16 kg, ASTM D1238 melting 124.5 ° C. point 25% Z9450 Total Propylene/Ethylene EPC density 0.89 g/cc Petrochemicals Copolymer - melt 5 g/10 min Single Site flow rate, 230, ° C., 2.16 kg, ASTM D1238 melting 128 ° C. point 20% 10414-08 Colortech Zeolite in LDPE2 density 1.02 g/cc Polyethylene, melt 6 g/10 min Low Density flow (odour rate, absorber) 190, ° C., 2.16 kg, ASTM D1238 ash 19.6 % 5% IT-815 Ingenia Zinc Oxide in LLDPE3 density 1.17 g/cc Polymers Polyethylene, melt 15 g/10 min Linear Low flow Density (odour rate, absorber) 190, ° C., 2.16 kg, ASTM D1238 Masterbatch 2 100% n.a. in house 35% by weight density 2.1 g/cc of 13X molecular sieve zeolite in LDPE or VLDPE (odour absorber) Masterbatch 3 10% ZEEOSPHERE 3M Ceramic AntiBlock density 2.4 g/cc W410 Spheres (beads) - Alkali-Alumino- Silicate Ceramic 90% Engage 8137 Dow Polyethylene, VLDPE4 density 0.866 g/cc Chemical Very Low melt flow 13 g/10 min Density rate, 190, ° C., 2.16 kg, ASTM D1238 melting 56 ° C. point Masterbatch 4 88% SP2260 Westlake Ethylene/Methyl EMA density 0.944 g/cc (Westlake) Chemical Acrylate melt flow 2.1 g/10 min Copolymer - rate, More than 20 wt. % 190, ° C., comonomer 2.16 kg, ASTM D1238 melting 77 ° C. point 7% Irganox 1076 BASF Phenolic Additive1 density 1.02 g/cc (primary) (?) melting 51 ° C. point 5% Cobalt Shepherd Cobalt Additive2 density 1.23 g/cc Neodecanoate Chemical Neodecanoate (?) Masterbatch 5 42% Exceed ExxonMobil linear Low LLDPE1 density 0.9 g/cc 1012HA Density melt flow 1 g/10 min Ethylene/Hexene rate, Copolymer - 190, ° C., Linear, Single 2.16 kg, Site ASTM D1238 melting 115 ° C. point 35% DOWLEX DOW Linear Low LLDPE2 density 0.92 g/cc 2045.03 Density melt flow 1.1 g/10 min Ethylene/Octene rate, Copolymer - 190, ° C., Linear, 2.16 kg, Ziegler/Natta ASTM D1238 melting 124.5 ° C. point 23% Z9450 Total Propylene/Ethylene EPC density 0.89 g/cc Petrochemicals Copolymer - melt flow 5 g/10 min Single Site rate, 230, ° C., 2.16 kg, ASTM D1238 melting 128 ° C. point Masterbatch 6 70% 10414-08 Colortech Zeolite in LDPE2 density 1.02 g/cc Polyethylene, melt flow 6 g/10 min Low Density rate, (odour 190, ° C., absorber) 2.16 kg, ASTM D1238 ash 19.6 % 20% IT-748 Ingenia Magnesium LLDPE4 density 1.02 g/cc Polymers Oxide in melt flow 6 g/10 min Polyethylene, rate, Linear Low 190, ° C., Density 2.16 kg, ASTM D1238 ash 19.6 % 10% IT-815 Ingenia Zinc Oxide in LLDPE3 density 1.19 g/cc Polymers Polyethylene, melt flow 20 g/10 min Linear Low rate, Density (odour 190, ° C., absorber) 2.16 kg, ASTM D1238

(106) The examples according to the invention have been collected in Tables 3, 4 and 5.

(107) TABLE-US-00003 TABLE 3 Examples No Layer (thickness) Ex. 1 Ex. 2 Ex. 3 Ex. 4 3-layers layer 1 VLDPE1 66.00% VLDPE1 66.00% VLDPE1 66.00% VLDPE1 66.00% barrier (10.2μ) LDPE1 4.00% LDPE1 4.00% LDPE1 4.00% LDPE1 4.00% laminate MASTERBATCH1 25.00% MASTERBATCH1 25.00% MASTERBATCH1 25.00% MASTERBATCH1 25.00% (50.9μ) MASTERBATCH2 5.00% MASTERBATCH2 5.00% MASTERBATCH2 5.00% MASTERBATCH2 5.00% layer 2 OSMB2 90.00% OSMB2 90.00% OSMB2 90.00% OSMB2 90.00% (19.1μ) OSMB1 10.00% OSMB1 10.00% OSMB1 10.00% OSMB1 10.00% layer 3 LDPE3 70.00% LDPE3 70.00% LDPE3 70.00% LDPE3 70.00% (21.6μ) VLDPE3 30.00% VLDPE3 30.00% VLDPE3 30.00% VLDPE3 30.00% layer 4 ADHESIVE 1 - 100% ADHESIVE 1 - 100% ADHESIVE 1 - 100% ADHESIVE 2 - 100.% (0.5μ) layer 5 PET2 - 100% PET1 - 100% PET3 - 100% PET1 - 100% (12.7μ)

(108) TABLE-US-00004 TABLE 4 Examples No Layer (thickness) Ex. 5 Ex. 6 3-layers layer 1 VLDPE2 76.00% layer 1 VLDPE2 76.00% barrier (10.2μ) LDPE2 10.00% (7.9μ) LDPE2 10.00% laminate LDPE1 4.00% LDPE1 4.00% (Ex. 5: MASTERBATCH3 10.00% MASTERBATCH3 10.00% 50.9μ; layer 2 OSMB2 90.00% layer 2 OSMB2 90.00% Ex. 6: (19.1μ) OSMB1 10.00% (19.1μ) OSMB1 10.00% 50.1μ) layer 3 LDPE3 70.00% layer 3 LDPE3 70.00% (21.6μ) VLDPE3 30.00% (23.1μ) VLDPE3 30.00% layer 4 ADHESIVE 1 - 100% ADHESIVE 1 - 100% (0.5μ) layer 5 PET1 100.00% PET1 - 100% (12.2μ)

(109) TABLE-US-00005 TABLE 5 Examples No Layer (thickness) Ex. 7 Ex. 8 3-layer layer 1 VLDPE1 96.00% VLDPE1 59.00% barrier (10.2μ) LDPE1 4.00% LDPE1 4.00% laminate MASTERBATCH5 23.00% (50.9μ) MASTERBATCH6 10.00% VLDPE5 2.00% VLDPE6 2.00% layer 2 OSMB2 90.00% OSMB2 90.00% (19.1μ) MASTERBATCH4 10.00% MASTERBATCH4 10.00% layer 3 LDPE3 70.00% LDPE3 55.00% (21.6μ) VLDPE3 30.00% VLDPE3 30.00% MASTERBATCH2 15.00% layer 4 ADHESIVE 1 - 100% ADHESIVE 1 - 100% (0.5μ) layer 5 PET1 100.00% PET1 - 100% (12.2μ)

(110) The comparative example is reported in Table 6.

(111) TABLE-US-00006 TABLE 6 Comparative example No Layer (thickness) Comparative example. 5-layers layer 1 LDPE4 1.00% barrier (29μ) LDPE5 2.00% laminate LDPE6 47.00% (57μ) LDPE7 49.00% LDPE8 0.50% LDPE9 0.50% layer 2 LLDPE-md1 (4μ) 100.00% layer 3 EVOH 100.00% (5μ) layer 4 LLDPE-md1 100.00% (4μ) layer 5 LDPE6 50.00% (15μ) LDPE10 50.00% layer 6 ADHESIVE 3 (4μ) Layer 7 biaxially oriented PET film chemically primed/ (12μ) Monolayer PET film Corona treated, sold as Nuroll PKR 12 microns

(112) The films of the present invention have been prepared as follows:

(113) Layers 1-3, that is the sealant layer, oxygen scavenging layer, and bulk or abuse layer were co-extruded on a round die system on a blown film process. The extrusion system was configured to control blend ratios of layer components particularly for the oxygen scavenging layer to assure the desired ratio of oxygen scavenger component versus catalyst. Additionally, the extrusion system was configured to control layer thickness particularly for the oxygen scavenging layer as the amount of scavenging capacity is proportional to the layer thickness. Sealant layer thickness is also important to insure the desired seal strength for specific applications. Finally, the extrusion system—follows a well-defined set of conditions (SOC's) with limits to maintain good film flatness by stabilizing bubble geometry and quench rates, also important for further converting processes. Once the film is extruded it can be triggered and then laminated and slit or laminated and then triggered prior to slitting or several other logistical plans to achieve the final slit rolls to use for the packaging application.

(114) The extruded three-layers film was then laminated with an adhesive layer to a substrate layer made of PET that had been coated with aluminum oxide. The substrate was printed prior to lamination.

(115) Lamination of the three layer film to the substrate combines the properties of both to fit the needs of the final converting process that makes the final bags or pouches for the end use product.

(116) The laminated film is cured for the appropriate time and then activated. This activation utilizes electron beam energy at a dosage from about 70 to about 130 kGy, with a target of 100 kGy. The dosage level measured in kilograys (kGy) is verified by measuring percent gel in a specific PE sent through the activating unit adhered to the film; the percent gel is proportional to the dosage. A scavenging test is also carried out to insure the film is triggered and begins scavenging.

(117) From this point in the process, the film is time monitored during its exposure to ambient air.

(118) The comparative film was prepared as follows:

(119) Layers 1-5 were coextruded on a round die system on a blown film process. The coextruded five-layer film was then laminated with an adhesive layer to a substrate layer comprising PET that was corona treated.

(120) Peroxide Value.

(121) Peroxide Value is one of the most widely used tests for oxidative rancidity in oils and fats. Peroxide value is a measure of the concentration of peroxides and hydroperoxides formed in the initial stages of lipid oxidation. Milliequivalents of peroxide per kg of fat are measured by titration with iodide ion. It is difficult to provide a specific guideline relating peroxide value to rancidity. High peroxide values are a definite indication of a rancid fat, but moderate values may be the result of depletion of peroxides after reaching high concentrations. Peroxide value is applicable to all normal fats and oils, Peroxide testing can only be accurately performed on oils.

(122) AOCS Cd8-53 Standard Method

(123) Reagents and Solution

(124) 1. Acetic Acid—chloroform solution (7.2 ml Acetic Acid and 4.8 ml Chloroform).

(125) 2. Saturated Potassium Iodide solution. Store in the dark.

(126) 3. Sodium thiosulfate solution, 0.1N. Commercially available.

(127) 4. 1% Starch solution. Commercially available.

(128) 5. Distilled or deionized water.

(129) Procedure

(130) 1. Weigh 2.00 (±0.02)g of sample into a 100 ml glass stoppered Erlenmeyer flask. Record weight to the nearest 0.01 g.

(131) 2. By graduated cylinder, add 12 ml of the acetic acid—chloroform solution.

(132) 3. Swirl the flask until the sample is completely dissolved (careful warming on a hot plate may be necessary).

(133) 4. Using 1 ml Mohr pipette, add 0.2 ml of saturated potassium iodide solution.

(134) 5. Stopper the flask and swirl the contents of the flask for exactly one minute.

(135) 6. Immediately add by graduated cylinder, 12 ml of either distilled or deionized water, stopper and shake vigorously to liberate the iodine from the chloroform layer.

(136) 7. Fill the burette with 0.1N sodium thiosulfate.

(137) 8. If the starting color of the solution is deep red orange, titrate slowly with mixing until the color lightens. If the solution is initially a light amber color, go to step 9.

(138) 9. Using a dispensing device, add 1 ml of starch solution as indicator.

(139) 10. Titrate until the blue gray color disappears in the aqueous (upper layer).

(140) 11. Accurately record the mls of titrant used to two decimal places.

(141) Peroxide values of fresh oils are less than 10 milliequivalents/kg, when the peroxide value is between 30 and 40 milliequivalents/kg, a rancid taste is noticeable.

(142) A product containing unsaturated oils, namely corn and/or sunflower oil, was packed in with the oxygen scavenging film of the present invention; a product containing the same unsaturated oils was packed in with a conventional barrier film.

(143) The amount of peroxides produced in the package of the invention and in the conventional barrier package was measured as described above. The amount of peroxides produced in the package of the invention is significantly lower than the amount of peroxides produced in the comparative package.

(144) These findings support the fact that the oxygen scavenging film of the present invention is able to capture the oxygen present in the headspace thus reducing the degree of oxidation of the unsaturated oils contained in the packaged food.

(145) The excellent performance of the film of the present invention in term of oxygen capture provides a way to address the trend existing in the food marketplace to avoid the use of highly saturated oils in favor of unsaturated alternatives which are healthier but more oxygen sensitive.

(146) Furthermore, the film of the present invention is able to substantially capture the volatile compounds that are due to byproducts of the oxidation of the oxygen scavenging component, thus these films do not lead to significant deterioration of the organoleptic qualities of the packaged product due to the oxidation of the fats in cases more oxygen sensitive unsaturated oils are present in the product.

(147) The film of the present invention offers improvement in both shelf life and quality of the oxygen sensitive packaged products, in particular in the case of products wherein oxygen sensitive unsaturated oils are present, such as dried milk.