Scented multilayer films and method of making
This invention relates to flexible packaging materials based on multi-layered films. Specifically, it relates to multi-layered flexible packaging films wherein the individual films or webs are bonded to each other through an adhesive layer. More specifically, the invention relates to such flexible packaging materials that have at least one aroma embedded within at least one adhesive layer, and wherein the two films on either side of the aroma-embedded adhesive layer may have different permeation characteristics to the aroma. Thus, this invention relates to multi-layered film-based flexible packaging materials with enhanced aroma characteristics. Finally, this invention also relates to a process for making such flexible packaging materials.
1 . A laminated structure used for flexible packaging material, comprising:
(a) a first web;
(b) a second web; and
(c) an adhesive layer positioned between and in contact with said first web and said second web, said adhesive layer comprising a bonding material and at least one aroma generating substance;
wherein said first web's permeability of said aroma generating substance is greater than said second web's permeability of said aroma generating substance.
2 . The laminated structure recited in claim 1 , wherein said aroma generating substance permeates out from said laminated structure in one direction.
3 . The laminated structure recited in claim 1 , wherein said bonding material in said adhesive layer is selected from the group consisting of extrusion-laminating adhesive, water-borne adhesive, solvent-borne adhesive, radiation-curable adhesive, multiple-part reactive adhesive, and mixtures thereof.
4 . The laminated structure recited in claim 1 , wherein said first web and/or said second web comprises at least one film layer, said film layer comprising polymeric compound selected from the group consisting of polyethylene, polypropylene, polybutylene, copolymers of propylene with ethylene, copolymers of propylene with butene-1, copolymers of butene-1 with ethylene, copolymers of ethylene and butylene, terpolymers of propylene-ethylene-butylene, cyclic olefins, styrene-butadiene copolymer, polystyrene, polyester, polyamide, and ionomers.
5 . The multi-layered structure recited in claim 4 , wherein said first web and/or said second web comprises a biaxially oriented polypropylene film.
6 . A process for preparing a flexible packaging material capable of releasing aroma, comprising:
(a) providing a first web;
(b) providing a second web; and
(c) providing an adhesive layer positioned between and in contact with said first web and said second web, said adhesive layer comprising a bonding material and at least one aroma generating substance;
wherein said first web's permeability of said aroma generating substance is greater than said second web's permeability of said aroma generating substance.
7 . The process recited in claim 6 , wherein said aroma generating substance permeates out from said laminated structure in one direction.
8 . The process recited in claim 6 , wherein said bonding material in said adhesive layer is selected from the group consisting of extrusion-laminating adhesive, water-borne adhesive, solvent-borne adhesive, radiation-curable adhesive, multiple-part reactive adhesive, and mixtures thereof.
9 . The process recited in claim 6 , wherein said first web and/or said second web comprises at least one film layer, said film layer comprising polymeric compound selected from the group consisting of polypropylene, polyethylene, copolymers of propylene with ethylene, copolymers of propylene with butene-1, polystyrene, polyester, polyamide, and ionomers.
10 . The multi-layered structure of claim 9 , wherein said first web and/or said second web comprises a biaxially oriented polypropylene film.