Recyclable films and packaging
A recyclable film contains a base film of polyethylene that has been oriented, annealed, and irradiatively crosslinked, and a sealant. The base film has a free shrink rate of less than 10% in both the machine direction and the transverse direction when exposed to heat of 90° C. These recyclable films are ideal for use as packaging components that can be hermetically heat sealed to themselves or other packaging components, while maintaining low shrink and excellent appearance.
1. A recyclable film comprising:
a. a base film comprising a composition consisting of high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, or combinations thereof, the base film being oriented, annealed and irradiatively cross-linked, and
b. a sealant,
wherein the base film has a free shrink rate of less than 10% in the machine direction and a free shrink rate of less than 10% in the transverse direction upon application of heat up to 90° C., and the base film has a clarity of at least 85%.
2. A recyclable film according to claim 1 wherein the base film has a free shrink rate of less than 5% in the machine direction and less than 5% in the transverse direction upon application of heat up to 90° C.
3. A recyclable film according to claim 1 wherein a logarithmic plot of the apparent shear viscosity of the base film versus apparent shear rate, of data points measured at 10 logarithmically spaced data points from 1 s −1 to 100,000 s −1 shear rate, results in a substantially straight line.
4. A recyclable film according to claim 1 wherein onset of sticking by an outer surface of the base film upon exposure to heat sealing conditions is at least 5 to 15° C. higher than a comparative outer surface of a comparative film comprising the same materials that is not irradiatively cross-linked.
5. A recyclable film according to claim 1 wherein the sealant is an extruded film comprising polyethylene, polyethylene copolymers or blends thereof.
6. A recyclable film according to claim 1 wherein the sealant comprises a surface layer and the surface layer comprises an ethylene vinyl acetate copolymer.
7. A recyclable film according to claim 1 wherein the sealant is a heat seal coating.
8. A recyclable film according to claim 7 wherein the heat seal coating has a heat seal initiation temperature lower than 250° F.
9. A recyclable film according to claim 1 wherein the sealant is an extruded film comprising:
a. an ethylene vinyl alcohol copolymer or polyamide, and
b. a polar polymer compatibilizer.
10. A recyclable film according to claim 1 further comprising printed indicia.
11. A package for a product comprising the recyclable film of claim 1 .
12. A package for a product, the package comprising a recyclable film according to claim 1 , heat sealed to itself or another packaging component, wherein the heat seal is manually openable.
13. A package for a product, the package comprising a recyclable film according to claim 1 , heat sealed to itself or another packaging component, wherein the heat seal strength is between about 200 g/in and 2,500 g/in when measured according to ASTM F88.
14. A package for a product comprising:
a. a lid comprising a recyclable film according to claim 1 ,
b. a tray or cup, and
c. a peelable heat seal connecting the lid and the tray or cup.
15. A package according to claim 14 wherein the tray or cup comprises polyester, polyethylene, polypropylene, coated paper, polystyrene, glass, ceramic or aluminum.
16. A recyclable film comprising:
a. a coextruded base film and comprising a medium density polyethylene layer positioned between an outer high density polyethylene layer and an inner high density polyethylene layer, the base film being oriented, annealed and irradiatively cross-linked, and
b. a sealant,
wherein the base film has a free shrink rate of less than 10% in the machine direction and a free shrink rate of less than 10% in the transverse direction upon application of heat up to 90° C., and the base film has a clarity of at least 85%.
17. A recyclable film according to claim 16 wherein the outer and inner high density polyethylene layers of the base film further comprise linear low density polyethylene.