Multilayer sealant film
AssigneeDuPont Teijin Films U.S. Limited Partnership
InventorFenghua Deng
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Abstract
A multilayer film suitable for sealing containers such as used for food packaging, and methods of making the film, are described. The film is particularly suitable for sealing containers made from polylactic acid (PLA). The multilayer film includes a) a substrate that includes a polymeric base layer; and b) on the substrate, a heatseal layer containing a PLA homopolymer or copolymer. The heatseal layer further includes dispersed therein an adhesion promoter, or alternatively the substrate further includes the adhesion promoter in a layer on a surface of the polymeric base layer between and adjacent the base layer and the heatseal layer. An antifog agent may also be included in the heatseal layer or on the surface of the heatseal layer opposite the substrate.
Claims24
A multilayer film comprising
- a) a substrate comprising a polymeric base layer;
- and
- b) on the substrate, a heatseal layer comprising a PLA polymer;
- wherein the heatseal layer further comprises dispersed therein an adhesion promoter;
- and
- wherein the adhesion promoter is a copolyester resin derived from one or more glycols, at least one aromatic dicarboxylic acid, and at least one aliphatic dicarboxylic acid, and wherein the polymeric base layer comprises a biaxially oriented polyester.
A multilayer film comprising
- a) a substrate comprising a polymeric base layer;
- and
- b) on the substrate, a heatseal layer comprising a PLA polymer;
- wherein the heatseal layer further comprises dispersed therein an adhesion promoter, wherein the adhesion promoter is a copolyester;
- and
- wherein the heatseal layer comprises a dispersed polymeric phase and a continuous polymeric phase of different composition therefrom, wherein the adhesion promoter constitutes more than 50 wt % of one of said phases and the PLA polymer constitutes more than 50 wt % of the other of said phases.
Dependencies are inferred from the claim text.