Easy-open reclosable films having an interior frangible interface and articles made therefrom
The present invention relates to peelable resealable multilayer films which include at least a first polymer layer, a second polymer layer of pressure-sensitive adhesive in direct contact with and bonded to both the first and third layers. The bond formed between the second and third layers includes a peelable resealable interface having a first interfacial peel strength, A, and a second interfacial peel strength, B. The peelable resealable interface includes a first interfacial peel strength, A, having a value of less than 3500 gram-force/inch (1350 newton/meter) as measured in accordance with ASTM F-904-98 test method when the films of the present invention are peeled from a second thermoplastic film to which the film has been heat-sealed. The second interfacial peel strength, B, has a value of at least 400 gram-force/inch (154 newton/meter) as measured in accordance with ASTM F-904-98 test method when the films are peeled from and re-adhered to a second film.
1. A peelable resealable multilayer film comprising:
at least a first thermoplastic layer, a second thermoplastic layer and a third thermoplastic layer;
wherein said first layer is an exterior film layer and comprises a homopolymer or copolymer selected from the group consisting of polyolefin, ionomer and blends thereof;
wherein said second layer is in direct contact with and bonded to both said first and third layers; wherein said second layer comprises a tacky pressure-sensitive adhesive;
wherein said third layer comprises an ethylene/vinyl alcohol copolymer or blends thereof;
wherein said bond between said second and third layers comprises a peelable resealable interface having a first interfacial peel strength “A” and a second interfacial peel strength “B” such that the value of A is less than 3500 gram-force/inch (1350 newton/meter) as measured in accordance with ASTM F-904 test method when peeled from a second thermoplastic film to which said film has been heat-sealed, and the value of B is at least 330 gram-force/inch (127 newton/meter) as measured in accordance with ASTM F-904 when peeled from and resealed to said second film;
and wherein the relative values of A and B satisfy the relationship A≧B.
2. The film according to claim 1 , wherein said film is coextruded by either slot cast or blown film coextrusion.
3. The film according to claim 1 , wherein said polyolefin comprises a homopolymer or copolymer selected from the group consisting of polyethylene, polypropylene, polybutylene and blends thereof.
4. The film according to claim 1 , wherein said first layer comprises an ionomer or blend thereof.
5. The film according to claim 1 , wherein said bond between said first and second layers has an interfacial peel strength of at least 3500 gram-force/inch (1350 newton/meter) as measured in accordance with ASTM F-904 test method when peeled from a second thermoplastic film to which said film has been heat-sealed.
6. The film according to claim 1 , wherein said value of B is at least 400 gram-force/inch (154 newton/meter) as measured in accordance with ASTM F-904.
7. The film according to claim 1 , wherein said tacky pressure sensitive adhesive comprises a tackifier first component and an elastomer second component of styrene/rubber copolymer.
8. The film according to claim 1 , wherein said third layer comprises a polymer having a glass transition temperature of at least 5° C. as measured in accordance with ASTM D-3418 test method.