Patent ID: 8507097

Claim:
A transparent multilayer film comprising: A. a first film layer comprising a fluorinated copolymer resin composition wherein i) the fluorinated copolymer comprises copolymerized units of tetrafluoroethylene and copolymerized units of comonomers selected from the group consisting of ethylene, perfluorinated comonomer, and combinations thereof, and ii) at least one surface of the first film layer has been modified by a surface treatment; and B. a second film layer consisting essentially of a blend composition, said blend composition comprising about 10 to about 90 wt % of an Ethylene Copolymer 1 and about 90 to about 10 wt % of an Ethylene Copolymer 2, based on the total weight of the blend composition, and said blend composition consisting essentially of an Ethylene Copolymer 1 and an Ethylene Copolymer 2; said Ethylene Copolymer 1 consists essentially of copolymerized units of ethylene, optionally about 5 to about 40 wt % of copolymerized units of a first olefin having a formula of CH 2 ═C(R 1 )CO 2 R 2 , and about 2 to about 30 wt % of copolymerized units of a second olefin having a formula of CH 2 ═C(R 3 )COOH, wherein the weight percentages of the copolymerized units of the first olefin and of the second olefin are based on the total weight of said Ethylene Copolymer 1; wherein about 10 to about 90 wt % of the carboxylic acid groups are neutralized to form carboxylate salts; wherein R 1 represents hydrogen or an alkyl group, R 2 represents an alkyl group, and R 3 represents hydrogen or an alkyl group; and wherein said Ethylene Copolymer 2 consists essentially of copolymerized units of ethylene, optionally up to about 40 wt % of copolymerized units of the first olefin, and about 3 to about 15 wt % of copolymerized units of a third olefin having a formula of CH 2 ═C(R 4 )-D, wherein the weight percentages of the copolymerized units of the first olefin and of the third olefin are based on the total weight of said Ethylene Copolymer 2; wherein R 4 represents hydrogen or an alkyl group; wherein -D represents a moiety selected from the group consisting of —CO 2 R 5 , —CO 2 R 6 —R 5 , —R 6 —R 5 , —O—R 5 , and —R 5 ; wherein R 5 represents a moiety containing an epoxy group and R 6 represents an alkylene group; wherein the blend composition, being held at 120° C. for up to about 15 minutes, does not cross-link to the extent that the blend composition becomes intractable for further processing; and with the proviso that none of said first, second or third olefins is a dicarboxylic acid or a di-ester, mono-ester or anhydride of the dicarboxylic acid; and wherein a surface of the second film layer is adhered to the modified surface of the first film layer.