# US 5,707,750 A · Retortable, high oxygen barrier polymeric films > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,750 A - Document ID: US5707750A - Status: Granted - Kind: A - Application number: 08/328,300 - Filed: 1994-10-24 - Granted: 1998-01-13 - Earliest claimed: 1994-10-24 - Assignees: AlliedSignal Inc. - Inventors: Alfieri Degrassi; James Ivan Fryer; Andrew Gerard Hitzel; Michael Stanley Matas - Web page: https://patentgrep.com/patent/US5707750A ## CPC - B32B 27/08: of synthetic resin - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 27/306: {comprising vinyl acetate or vinyl alcohol (co)polymers} - B32B 27/34: comprising polyamides - B32B 2250/05: 5 or more layers - B32B 2250/24: All layers being polymeric - B32B 2307/7244: Oxygen barrier - B32B 2329/00: Polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals - B32B 2377/00: Polyamides - B32B 2439/70: Food packaging - Y10S 428/91: Product with molecular orientation - Y10T 428/31739: Nylon type - Y10T 428/31743: Next to addition polymer from unsaturated monomer[s] - Y10T 428/31746: Polymer of monoethylenically unsaturated hydrocarbon - Y10T 428/3175: Next to addition polymer from unsaturated monomer[s] - Y10T 428/31757: Polymer of monoethylenically unsaturated hydrocarbon - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A polymeric film having superior oxygen barrier properties comprising at least five layers with two exterior layers independently selected from the group consisting of an aliphatic polyamide and an aliphatic/aromatic polyamide, an interior layer of ethylene vinyl alcohol copolymer or a blend of poly(m-xylylene adipamide) and ethylene vinyl alcohol copolymer, and a modified polyolefin adhesive layer between each exterior layer and the interior layer. ## Claims ### Claim 1 A film having at least five layers comprised of: a) a first and second exterior layer independently comprised of a polymer selected from the group consisting of polyamides, aliphatic/aromatic polyamides having the formula ##STR3## and blends thereof, b) an interior layer which comprises a blend of an aliphatic/aromatic polyamide having the formula ##STR4## and an ethylene vinyl alcohol copolymer; and c) a modified polyolefin adhesive layer positioned between each exterior layer and the interior layer, wherein said film is retortable, and wherein R.sup.2 and R.sup.3 are different and are an alkylene group having at least 2 carbon atoms or an arylene group, with the proviso that when R.sup.2 is alkylene, R.sup.3 is arylene and when R.sup.2 is arylene, R.sup.3 is alkylene. ### Claim 2 (depends on 1) A film according to claim 1 wherein said aliphatic polyamide is selected from the group consisting of polyamides having recurring monomeric units of the formula ##STR5## and a combination thereof wherein: R and R.sup.1 are the same or different and are alkylene having from about 2 to about 12 carbon atoms. ### Claim 3 (depends on 2) A film according to claim 2 wherein said aliphatic polyamide is selected from the group consisting of poly(hexamethylene adipamide), poly(4-aminobutyric acid), poly(caprolactam), poly(7-aminoheptanoic acid) and copolymers of caprolactam and hexamethylene adipamide. ### Claim 4 (depends on 2) A film according to claim 2 wherein said aliphatic polyamide is poly(caprolactam), poly(hexamethylene adipamide) or a combination thereof. ### Claim 5 (depends on 2) A film according to claim 2 wherein said aliphatic polyamide is poly(caprolactam). ### Claim 6 (depends on 1) A film according to claim 1 wherein each of said adhesive layers independently comprises a modified poly(C.sub.2 to C.sub.6 .alpha.-olefin), and about 0.1 to about 15 weight percent, based on the total weight of said modified poly(C.sub.2 to C.sub.6 .alpha.-olefin), of a functional moiety selected from the group consisting of unsaturated polycarboxylic acids and acid anhydrides. ### Claim 7 (depends on 6) A film according to claim 6 wherein said functional moiety is selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, crotonoic acid, citraconic anhydride, and itaconic anhydride. ### Claim 8 (depends on 7) A film according to claim 7 wherein said functional moiety is maleic anhydride. ### Claim 9 (depends on 6) A film according to claim 6 wherein said modified poly(.alpha.-olefin) is selected from the group consisting of low, medium or high density polyethylene, linear low density polyethylene, polypropylene, polybutylene, polybutene-1, polypentene-1, poly-3-methylbutene-1, poly-4-methylpentene-1, polyhexene, and copolymers and blends thereof. ### Claim 10 (depends on 9) A film according to claim 9 wherein said modified poly(C.sub.2 to C.sub.6 .alpha.-olefin) further comprises from about 0.01 to about 1 weight percent, based on the total weight of said modified poly(C.sub.2 to C.sub.6 .alpha.-olefin), of vinyl acetate moiety. ### Claim 11 (depends on 10) A film according to claim 10 wherein said modified poly(C.sub.2 to C.sub.6 .alpha.-olefin) further comprises a thermoplastic elastomer selected from the group consisting of ethylene/propylene rubber, ethylene/1-butene rubber, butyl rubber, butadiene rubber, sytrene/butadiene rubber, ethylene/butadiene rubber, isopropene rubber, and isobutylene. ### Claim 12 (depends on 10) A film according to claim 10 wherein said modified poly(C.sub.2 to C.sub.6 .alpha.-olefin) comprises .alpha.-olefin, about 0.01 to about 0.5 weight percent of vinyl acetate and about 0.1 to about 12 weight percent, based on the total weight of the modified poly(C.sub.2 to C.sub.6 .alpha.-olefin), of maleic anhydride. ### Claim 13 (depends on 1) A film according to claim 1 having an oxygen permeability at 90% relative humidity equal to or less than about 0.06 cm.sup.3 /100 in .sup.2 /24 hrs./Atm. when measured according to ASTM D 3985. ### Claim 14 (depends on 1) A film according to claim 1 wherein each said aliphatic/aromatic polyamide is selected from the group consisting of poly(hexamethylene isophthalamide), poly(2,2,2-trimethyl hexamethylene terephthalamide), poly(m-xylylene adipamide), poly(p-xylylene adipamide), poly(hexamethylene terephthalamide), and poly(dodecamethylene terephthalamide). ### Claim 15 (depends on 1) A film according to claim 1 wherein said interior layer is a blend of EVOH copolymer and poly(m-xylylene adipamide). ### Claim 16 (depends on 15) A film according to claim 15 wherein said interior layer contains, based upon the total weight of the interior layer, between about 65 wt % to about 85 wt % of said poly(m-xylylene adipamide) blended with about 15 wt % to about 35 wt % of said EVOH copolymer. ### Claim 17 (depends on 1) A film according to claim 1 wherein: said exterior layers are comprised of poly(caprolactam); and said adhesive layer is comprised of modified poly(.alpha.-olefin) comprising .alpha.-olefin, about 0.01 to about 0.3 weight percent of vinyl acetate and about 5 to about 10 weight percent, based on the total weight of the modified poly(.alpha.-olefin), of maleic anhydride, wherein said film having an oxygen permeability at 90% relative humidity equal to or less than about 0.06 cm.sup.3 /100 in .sup.2 /24 hrs./Atm. when measured according to ASTM D 3985. ### Claim 18 (depends on 1) A film according to claim 1 wherein: said exterior layers are independently comprised of a polymer selected from the group consisting of poly(caprolactam), poly(hexamethylene adipamide) and caprolactam/hexamethylene adipamide copolymer; and said adhesive layer is comprised of modified poly(.alpha.-olefin) comprising ethylene about 0.01 to about 0.3 weight percent of vinyl acetate and about 0.1 to about 12 weight percent, based on the total weight of the modified poly(.alpha.-olefin), of maleic anhydride, said film having an oxygen permeability at 90% relative humidity equal to or less than about 0.06 cm.sup.3 /100 in .sup.2 /24 hrs./Atm. when measured according to ASTM D 3985. ### Claim 19 (depends on 18) A film according to claim 18 wherein said aliphatic polyamide is poly(caprolactam). ### Claim 20 (depends on 1) A film according to claim 1 wherein said film is oriented. ### Claim 21 (depends on 1) A film according to claim 1 wherein said film is oriented uniaxially. ### Claim 22 (depends on 21) A film according to claim 21 wherein said film is oriented at a draw ratio from about 3:1 to about 6:1. ### Claim 23 A process for producing a retortable film comprising: a) juxtaposing a modified polyolefin adhesive layer onto both sides of an interior layer comprised of a blend of an aliphatic/aromatic polyamide having the formula ##STR6## and an ethylene vinyl alcohol copolymer, to form a three-layered combination; b) juxtaposing a first and second exterior layer independently comprised of a polymer selected from the group consisting of aliphatic polyamides, aliphatic/aromatic polyamides having the formula ##STR7## and blends thereof, onto both sides of said three-layered combination, whereby said interior and exterior layers are bonded together through said adhesive layers, wherein R.sup.2 and R.sup.3 are different and are an alkylene group having at least 2 carbon atoms or an arylene group, with the proviso that when R.sup.2 is alkylene, R.sup.3 is arylene and when R.sup.2 is arylene, R.sup.3 is alkylene.