Multilayer films for reclosable packaging
AssigneeE. I. Du Pont de Nemours and Company
InventorsYves M Trouilhet, Jacques Roulin
Life of this patent
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Abstract
Disclosed is a multilayer structure that comprises a heat sealable layer comprising amorphous polyethylene terephthalate with a melting point greater than 200° C., a pressure sensitive adhesive and at least one tie layer encapsulating the pressure sensitive adhesive. The structure can be coextruded without degrading the pressure sensitive adhesive. Also disclosed is a reclosable package comprising the structure and methods to make such structures.
Claims11
A multilayer structure comprising a heat sealable layer, a pressure-sensitive adhesive layer, a tie layer, a structure layer, and optionally an additional tie layer wherein
- the heat sealable layer comprises amorphous polyethylene terephthalate having a melting temperature above 200° C. and is a semi-aromatic polyethylene terephthalate;
- the tie layer comprising a polymer composition having a melting temperature of about 80 to about 120° C. wherein one face of the tie layer is in direct contact with the pressure-sensitive adhesive layer and the other face of the tie layer is in direct contact with the structure layer;
- the structure layer comprises an ethylene homopolymer, ethylene α-olefin copolymer, propylene homopolymer, propylene α-olefin copolymer, polyethylene terephthalate, metallized polyethylene terephthalate, oriented polypropylene, oriented polyamide, polyvinyl chloride, polyacrylonitrile, paper, foil, non-woven fabric, or combinations thereof;
- and wherein at least one of the compositions of the heat sealable layer or the structure layer has a melting point significantly higher than the degradation temperature of the pressure sensitive adhesive;
- the pressure-sensitive adhesive layer is characterized by cohesive failure when the multilayer structure is subjected to a peel force of less than or equal to about 11 N/cm;
- and
- one face of the additional tie layer, if present, is in direct contact with the heat sealable layer and the other face of layer the additional tie layer is in direct contact with the pressure-sensitive adhesive layer.
Dependencies are inferred from the claim text.