Formable films, laminate structures, and related methods
Formable films are provided that include one or more biaxially-oriented polyethylene terephthalate layers. The formable films include a metaphase with a metaphase transition of about 180° C. to 200° C. as measured by differential scanning calorimetry (DSC). The formable films further include a molded volume of greater than 200%. Laminate structures including the formable films and processes for producing and using the formable films and laminate structures are also provided.
1. A film, comprising one or more biaxially-oriented polyethylene terephthalate layers, the film having:
a metaphase with a metaphase transition present at about 180° C. to about 200° C. as measured by differential scanning calorimetry (DSC) upon a first heating; and
a molded volume of greater than about 200%.
2. The film of claim 1 , wherein the film has a machine direction total elongation percentage of about 180% to about 300%.
3. The film of claim 1 , wherein the film has a transverse direction total elongation percentage of about 100% to about 300%.
4. The film of claim 1 , wherein the film has a thickness of about 9 μm to about 50 μm.
5. The film of claim 1 , wherein the film further comprises an acrylic coating, a polyurethane coating, a polysulphonester coating, or a quaternary ammonium-based coating.
6. The film of claim 1 , wherein the metaphase is configured to increase a property of the film selected from the group consisting of tensile strength, drawability, formability, and combinations thereof.
7. The film of claim 1 , wherein the film includes:
a machine direction tensile strength of greater than about 2000 kgf/cm at 25° C.;
a transverse direction tensile strength of greater than about 2500 kgf/cm at 25° C.;
a machine direction total elongation percentage measured at 25° C. of greater than about 200%; and/or
a ratio of transverse direction:machine direction tensile strength of greater than about 1.25.
8. The film of claim 1 , wherein at least one of the one or more biaxially-oriented polyethylene terephthalate layers is comprised of a polyethylene terephthalate homopolymer or is comprised of polyethylene terephthalate copolyester.
9. The film of claim 1 , wherein the film includes at least two biaxially-oriented polyethylene terephthalate layers.
10. The film of claim 9 , wherein the film includes three biaxially-oriented polyethylene terephthalate layers.
11. The film of claim 10 , wherein at least one of the three biaxially-oriented polyethylene terephthalate layers includes silica.
12. The film of claim 10 , wherein the film includes an A/B/A structure comprising a first polyethylene terephthalate layer, a silica-containing polyethylene terephthalate layer, and a second polyethylene terephthalate layer.
13. The film of claim 1 , wherein the film has a machine direction tensile strength of greater than about 2000 kgf/cm at 25° C.
14. The film of claim 1 , wherein the film has a transverse direction tensile strength of greater than about 2500 kgf/cm at 25° C.
15. The film of claim 1 , wherein the film has a machine direction total elongation percentage of greater than about 200% at 25° C.
16. The film of claim 1 , wherein the film has a transverse direction total elongation percentage of greater than about 90% at 25° C.
17. A film, comprising one or more biaxially-oriented polyethylene terephthalate layers, the film including a metastable phase having a phase transition temperature of about 50° C. less than the crystalline melting point of the film as measured by differential scanning calorimetry (DSC).
18. The film of claim 17 , wherein the film is capable of forming a cavity with little spring-back force.
19. A laminate structure, comprising:
a film including one or more biaxially-oriented polyethylene terephthalate layers, the film having
a metaphase with a metaphase transition present at about 180° C. to about 200° C. as measured by differential scanning calorimetry (DSC) upon a first heating, and
a molded volume of greater than about 200%; and
one or more additional layers laminated to the one or more biaxially-oriented polyethylene terephthalate layers.
20. The laminate structure of claim 19 , wherein the metaphase has a phase transition temperature of about 50° C. less than the crystalline melting point of the film as measured by differential scanning calorimetry (DSC).
21. The laminate structure of claim 19 , wherein the one or more additional layers are selected from an aluminum foil layer and a polyvinyl chloride layer.
22. The laminate structure of claim 19 , wherein the one or more biaxially-oriented polyethylene terephthalate layers comprises a single biaxially-oriented polyethylene terephthalate layer, and wherein the one or more additional layers comprises an aluminum foil layer laminated to the single biaxially-oriented polyethylene terephthalate layer and a polyvinyl chloride layer laminated to the aluminum foil layer.
23. The laminate structure of claim 19 , wherein the one or more biaxially-oriented polyethylene terephthalate layers comprises a first biaxially-oriented polyethylene terephthalate layer and a second biaxially-oriented polyethylene terephthalate layer, and wherein the one or more additional layers comprises an aluminum foil layer interposed between the first biaxially-oriented polyethylene terephthalate layer and the second biaxially-oriented polyethylene terephthalate layer.
24. The laminate structure of claim 23 , wherein the first biaxially-oriented polyethylene terephthalate layer includes an isophthalate copolyester skin layer.
25. The laminate structure of claim 19 , wherein the one or more additional layers are laminated to the one or more biaxially-oriented polyethylene terephthalate layers with an adhesive.
26. The laminate structure of claim 19 , wherein the laminate structure has a puncture strength greater than about 9.00 N/mm 2 .
27. The laminate structure of claim 19 , wherein the laminate structure has a dart impact strength greater than about 650 g/cm 2 .